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1
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Banerjee R. Tiny but Mighty: Small RNAs-The Micromanagers of Bacterial Survival, Virulence, and Host-Pathogen Interactions. Noncoding RNA 2025; 11:36. [PMID: 40407594 PMCID: PMC12101431 DOI: 10.3390/ncrna11030036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2025] [Revised: 04/07/2025] [Accepted: 04/28/2025] [Indexed: 05/26/2025] Open
Abstract
Bacterial pathogens have evolved diverse strategies to infect hosts, evade immune responses, and establish successful infections. While the role of transcription factors in bacterial virulence is well documented, emerging evidence highlights the significant contribution of small regulatory RNAs (sRNAs) in bacterial pathogenesis. These sRNAs function as posttranscriptional regulators that fine-tune gene expression, enabling bacteria to adapt rapidly to challenging environments. This review explores the multifaceted roles of bacterial sRNAs in host-pathogen interactions. Firstly, it examines how sRNAs regulate pathogenicity by modulating the expression of key virulence factors, including fimbriae, toxins, and secretion systems, followed by discussing the role of sRNAs in bacterial stress response mechanisms that counteract host immune defenses, such as oxidative and envelope stress. Additionally, this review investigates the involvement of sRNAs in antibiotic resistance by regulating efflux pumps, biofilm formation, and membrane modifications, which contribute to multi-drug resistance phenotypes. Lastly, this review highlights how sRNAs contribute to intra- and interspecies communication through quorum sensing, thereby coordinating bacterial behavior in response to environmental cues. Understanding these regulatory networks governed by sRNAs is essential for the development of innovative antimicrobial strategies. This review highlights the growing significance of sRNAs in bacterial pathogenicity and explores their potential as therapeutic targets for the treatment of bacterial infections.
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Affiliation(s)
- Rajdeep Banerjee
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
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2
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De Padua JC, Kikuchi T, Sakakibara F, De Leon AM, Bungihan ME, Ueno K, Dela Cruz TEE, Ishihara A. Novel compound, pleuropyronine, and other polyketides isolated from the edible mushroom Pleurotus ostreatus suppress bacterial biofilm formation. Biosci Biotechnol Biochem 2024; 89:11-21. [PMID: 39424595 DOI: 10.1093/bbb/zbae148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2024] [Accepted: 10/15/2024] [Indexed: 10/21/2024]
Abstract
An increase in the number of drug-resistant microbes is a major threat to human health. Bacterial drug resistance is mostly mediated by biofilm formation. In this study, the culture filtrate from the edible mushroom, Pleurotus ostreatus, was fractionated to isolate compounds that inhibit the biofilm formation of six pathogenic bacteria. Notably, we isolated compounds 1-6 using bioassay-guided chromatographic separations. Spectroscopic and X-ray diffraction analyses identified 1 as a novel fused bicyclic pyrone-furan, named pleuropyronine, whereas 2-6 were known polyketides. Pleuropyronine inhibited biofilm formation in four Gram-negative bacteria, with IC50 values ranging from 5.4 to 8.7 µg/mL, whereas 2-6 exhibited IC50 values between 1.0 and 5.3 µg/mL against five bacteria. Additionally, pleuropyronine bioactivity was confirmed by the inhibition of exopolysaccharide and biofilm formation induced by C6-homoserine lactone. Thus, this may serve as a pioneering study on the pharmacological potential of isolated compounds, offering valuable insights for future research.
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Affiliation(s)
- Jewel C De Padua
- The United Graduate School of Agricultural Sciences, Tottori University, Tottori, Japan
| | - Takashi Kikuchi
- Rigaku Corporation, Akishima-shi, Tokyo, Japan
- Novel Compounds Exploration Research Organization, Tsukuba, Japan
| | - Futa Sakakibara
- Novel Compounds Exploration Research Organization, Tsukuba, Japan
| | - Angeles M De Leon
- Department of Biological Sciences, College of Science, Central Luzon State University, Science City of Muñoz, Nueva Ecija, Philippines
| | - Melfei E Bungihan
- Department of Chemistry, College of Science, University of Santo Tomas, España Blvd., Manila, Philippines
- Research Center for the Natural and Applied Sciences, University of Santo Tomas, España Blvd., Manila, Philippines
| | - Kotomi Ueno
- Department of Agricultural, Life, Environmental Sciences, Faculty of Agriculture, Tottori University, Tottori, Japan
| | - Thomas Edison E Dela Cruz
- Department of Biological Sciences, College of Science, University of Santo Tomas, España Blvd., Manila, Philippines
| | - Atsushi Ishihara
- Novel Compounds Exploration Research Organization, Tsukuba, Japan
- Department of Agricultural, Life, Environmental Sciences, Faculty of Agriculture, Tottori University, Tottori, Japan
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3
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Xiong Q, Zhang H, Shu X, Sun X, Feng H, Xu Z, Kovács ÁT, Zhang R, Liu Y. Autoinducer-2 relieves soil stress-induced dormancy of Bacillus velezensis by modulating sporulation signaling. NPJ Biofilms Microbiomes 2024; 10:117. [PMID: 39489748 PMCID: PMC11532509 DOI: 10.1038/s41522-024-00594-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Accepted: 10/18/2024] [Indexed: 11/05/2024] Open
Abstract
The collective behavior of bacteria is regulated by quorum sensing (QS). Autoinducer-2 (AI-2) is a common QS signal that regulates the behavior of both Gram-positive and Gram-negative bacteria. Despite the plethora of processes described to be influenced by AI-2 in diverse Gram-negative bacteria, the AI-2-regulated processes in Bacilli are relatively unexplored. Here, we describe a novel function for AI-2 in Bacillus velezensis SQR9 related to the sporulation. AI-2 inhibited the initiation of sporulation through the phosphatase RapC and the DNA binding regulator ComA. Using biochemistry experiments, we demonstrated that AI-2 interacts with RapC to stimulate its binding to ComA, which leads to an inactive ComA and subsequently a sporulation inhibition. The AI-2 molecule could be shared across species for inhibiting Bacillus sporulation and it also plays the same role in different soil conditions. Our study revealed a novel function and regulatory mechanism of AI-2 in inhibiting sporulation in Bacilli.
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Affiliation(s)
- Qin Xiong
- National Engineering Research Center of Navel Orange, Gannan Normal University, Ganzhou, 341000, PR China
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, 100081, Beijing, PR China
- Jiangxi Provincial Key Laboratory of Pest and Disease Control of Featured Horticultural Plants, Gannan Normal University, Gznzhou, PR China
| | - Huihui Zhang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Xia Shu
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, 100081, Beijing, PR China
| | - Xiting Sun
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, 100081, Beijing, PR China
| | - Haichao Feng
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Zhihui Xu
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Ákos T Kovács
- Faculty of Science - Institute of Biology, Leiden University, Sylviusweg 73, 2333BE, Leiden, Netherlands
- DTU Bioengineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Ruifu Zhang
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, 100081, Beijing, PR China
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Yunpeng Liu
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, 100081, Beijing, PR China.
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4
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Faruque SN, Yamasaki S, Faruque SM. Quorum regulated latent environmental cells of toxigenic Vibrio cholerae and their role in cholera outbreaks. Gut Pathog 2024; 16:52. [PMID: 39343919 PMCID: PMC11441007 DOI: 10.1186/s13099-024-00647-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2024] [Accepted: 09/23/2024] [Indexed: 10/01/2024] Open
Abstract
BACKGROUND Diverse bacterial group behaviors are controlled by quorum sensing, a regulatory network of bacterial gene expression based on cell density, and involving communication through chemical signal molecules called autoinducers. Multidisciplinary research in toxigenic Vibrio cholerae the etiologic agent of cholera, appear to suggest group behavior in the ecology, epidemiology, pathogenesis and transmission of the pathogen. This review summarizes latest advances and known aspects of quorum regulated environmental survival form of V. cholerae, and their role in cholera outbreaks, as well as the significance of this knowledge in tracking the pathogen for prevention of cholera. MAIN BODY Pathogenic V. cholerae naturally exists in aquatic reservoirs, and infects humans, often leading to epidemic outbreaks of cholera. Effective detection and monitoring of the pathogen in surface waters have been a research focus in preventing cholera outbreaks. However, in the aquatic reservoirs, V. cholerae persists mostly in a quiescent state referred to as viable but non-culturable (VBNC), or conditionally viable environmental cells (CVEC), which fail to grow in routine bacteriological culture. The presence of CVEC can, however, be observed by fluorescent antibody based microscopy, and they appear as clumps of cells embedded in an exopolysaccharide matrix. Current studies suggest that CVEC found in water are derived from in-vivo formed biofilms excreted by cholera patients. The transition to CVEC occurs when dilution of autoinducers in water blocks quorum-mediated regulatory responses that would normally disperse the cellular aggregates. Consequently, CVEC are resuscitated to actively growing cells if autoinducers are replenished, either in the laboratory, or naturally by other environmental bacteria or the intestinal microbiota when CVEC are ingested by humans or aquatic animals. CONCLUSION Quorum sensing plays a crucial role in the environmental persistence of toxigenic V. cholerae in a latent state, and their periodic emergence to cause cholera outbreaks. Furthermore, the autoinducer driven resuscitation of these cells may be a basis for improving the detection of V. cholerae in water samples, and monitoring V. cholerae in their aquatic reservoirs in cholera endemic areas.
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Affiliation(s)
- Shah Nayeem Faruque
- Laboratory Sciences and Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, 1212, Bangladesh
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Shinji Yamasaki
- Department of Veterinary Science, Graduate School of Veterinary Science, Osaka Metropolitan University, Osaka, 598-8531, Japan
- Osaka International Research Centre for Infectious Diseases, Osaka Metropolitan University, Osaka, 545-8585, Japan
| | - Shah M Faruque
- School of Environment and Life Sciences, Independent University, Bangladesh, Bashundhara R/A, Dhaka, 1229, Bangladesh.
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De Padua JC, Tanaka T, Ueno K, Dela Cruz TEE, Ishihara A. Isolation of 2,2'-azoxybisbenzyl alcohol from Agaricus subrutilescens and its inhibitory activity against bacterial biofilm formation. Biosci Biotechnol Biochem 2024; 88:983-991. [PMID: 38925646 DOI: 10.1093/bbb/zbae089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Accepted: 06/19/2024] [Indexed: 06/28/2024]
Abstract
Virulence pathways in pathogenic bacteria are regulated by quorum sensing mechanisms, particularly biofilm formation through autoinducer (AI) production and sensing. In this study, the culture filtrate extracted from an edible mushroom, Agaricus subrutilescens, was fractionated to isolate a compound that inhibits biofilm formation. Four gram-negative bacteria (Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis, and Enterobacter cloacae) and two gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus) were used for the bioassay. The bioassay-guided chromatographic separations of the culture filtrate extract resulted in the isolation of the compound. Further, spectroscopic analyses revealed the identity of the compound as 2,2'-azoxybisbenzyl alcohol (ABA). The minimum inhibitory and sub-inhibitory concentrations of the compound were also determined. Azoxybisbenzyl alcohol was significantly effective in inhibiting biofilm formation in all tested bacteria, with half-maximal inhibitory concentrations of 3-11 µg/mL. Additionally, the bioactivity of ABA was confirmed through the bioassays for the inhibition of exopolysaccharide matrixes and AI activities.
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Affiliation(s)
- Jewel C De Padua
- The United Graduate School of Agricultural Sciences, Tottori University, Tottori, Japan
| | - Tomoya Tanaka
- Graduate School of Sustainability Sciences, Tottori University, Tottori, Japan
| | - Kotomi Ueno
- Department of Agricultural, Life, Environmental Sciences, Faculty of Agriculture, Tottori University, Tottori, Japan
| | - Thomas Edison E Dela Cruz
- Department of Biological Sciences, College of Science, University of Santo Tomas, Manila, Philippines
| | - Atsushi Ishihara
- Department of Agricultural, Life, Environmental Sciences, Faculty of Agriculture, Tottori University, Tottori, Japan
- Fungus/Mushroom Resource and Research Center, Faculty of Agriculture, Tottori, Japan
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6
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Santoriello FJ, Bassler BL. The LuxO-OpaR quorum-sensing cascade differentially controls Vibriophage VP882 lysis-lysogeny decision making in liquid and on surfaces. PLoS Genet 2024; 20:e1011243. [PMID: 39078816 PMCID: PMC11315295 DOI: 10.1371/journal.pgen.1011243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 08/09/2024] [Accepted: 07/12/2024] [Indexed: 08/10/2024] Open
Abstract
Quorum sensing (QS) is a process of cell-to-cell communication that bacteria use to synchronize collective behaviors. QS relies on the production, release, and group-wide detection of extracellular signaling molecules called autoinducers. Vibrios use two QS systems: the LuxO-OpaR circuit and the VqmA-VqmR circuit. Both QS circuits control group behaviors including biofilm formation and surface motility. The Vibrio parahaemolyticus temperate phage φVP882 encodes a VqmA homolog (called VqmAφ). When VqmAφ is produced by φVP882 lysogens, it binds to the host-produced autoinducer called DPO and launches the φVP882 lytic cascade. This activity times induction of lysis with high host cell density and presumably promotes maximal phage transmission to new cells. Here, we explore whether, in addition to induction from lysogeny, QS controls the initial establishment of lysogeny by φVP882 in naïve host cells. Using mutagenesis, phage infection assays, and phenotypic analyses, we show that φVP882 connects its initial lysis-lysogeny decision to both host cell density and whether the host resides in liquid or on a surface. Host cells in the low-cell-density QS state primarily undergo lysogenic conversion. The QS regulator LuxO~P promotes φVP882 lysogenic conversion of low-cell-density planktonic host cells. By contrast, the ScrABC surface-sensing system regulates lysogenic conversion of low-cell-density surface-associated host cells. ScrABC controls the abundance of the second messenger molecule cyclic diguanylate, which in turn, modulates motility. The scrABC operon is only expressed when its QS repressor, OpaR, is absent. Thus, at low cell density, QS-dependent derepression of scrABC drives lysogenic conversion in surface-associated host cells. These results demonstrate that φVP882 integrates cues from multiple sensory pathways into its lifestyle decision making upon infection of a new host cell.
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Affiliation(s)
- Francis J. Santoriello
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Bonnie L. Bassler
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
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7
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Gao S, Mao C, Yuan S, Quan Y, Jin W, Shen Y, Zhang X, Wang Y, Yi L, Wang Y. AI-2 quorum sensing-induced galactose metabolism activation in Streptococcus suis enhances capsular polysaccharide-associated virulence. Vet Res 2024; 55:80. [PMID: 38886823 PMCID: PMC11184709 DOI: 10.1186/s13567-024-01335-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 05/29/2024] [Indexed: 06/20/2024] Open
Abstract
Bacteria utilize intercellular communication to orchestrate essential cellular processes, adapt to environmental changes, develop antibiotic tolerance, and enhance virulence. This communication, known as quorum sensing (QS), is mediated by the exchange of small signalling molecules called autoinducers. AI-2 QS, regulated by the metabolic enzyme LuxS (S-ribosylhomocysteine lyase), acts as a universal intercellular communication mechanism across gram-positive and gram-negative bacteria and is crucial for diverse bacterial processes. In this study, we demonstrated that in Streptococcus suis (S. suis), a notable zoonotic pathogen, AI-2 QS enhances galactose utilization, upregulates the Leloir pathway for capsular polysaccharide (CPS) precursor production, and boosts CPS synthesis, leading to increased resistance to macrophage phagocytosis. Additionally, our molecular docking and dynamics simulations suggest that, similar to S. pneumoniae, FruA, a fructose-specific phosphoenolpyruvate phosphotransferase system prevalent in gram-positive pathogens, may also function as an AI-2 membrane surface receptor in S. suis. In conclusion, our study demonstrated the significance of AI-2 in the synthesis of galactose metabolism-dependent CPS in S. suis. Additionally, we conducted a preliminary analysis of the potential role of FruA as a membrane surface receptor for S. suis AI-2.
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Affiliation(s)
- Shuji Gao
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- College of Life Science, Luoyang Normal University, Luoyang, 471934, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Chenlong Mao
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Shuo Yuan
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Yingying Quan
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Wenjie Jin
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Yamin Shen
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Xiaoling Zhang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Yuxin Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Li Yi
- College of Life Science, Luoyang Normal University, Luoyang, 471934, China.
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China.
| | - Yang Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China.
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China.
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8
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Spangler JR, Cooper DN, Malanoski AP, Walper SA. Promoter Identification and Optimization for the Response of Lactobacillus plantarum WCFS1 to the Gram-Negative Pathogen-Associated Molecule N-3-Oxododecanoyl Homoserine Lactone. ACS Biomater Sci Eng 2023; 9:5111-5122. [PMID: 35708239 DOI: 10.1021/acsbiomaterials.1c01191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Quorum sensing (QS) in bacteria has been well studied as a cellular communication phenomenon for decades. In recent years, such systems have been repurposed for the use of biosensors in both cellular and cell-free contexts as well as for inducible protein expression in nontraditional chassis organisms. Such biosensors are particularly intriguing when considering the association between the pathogenesis of some bacteria and their signaling intermediates. Considering this relationship and considering the recent demonstration of the species Lactobacillus plantarum WCFS1 as both a synthetic biology chassis and an organism capable of detecting a pathogen-associated QS molecule, we wanted to develop this organism as a QS sentinel. We used an approach combining techniques from both systems and synthetic biology to identify a number of native QS-response genes and to alter associated promoter activity to tune the output of L. plantarum cultures exposed to N-3-oxododecanoyl homoserine lactone. The resulting engineered QS sentinel reinforces the potential of modified lactic acid bacteria (LAB) for use in human-health-promoting applications and also demonstrates a simple rational workflow to engineer sentinel organisms to respond to any environmental or chemical stimuli.
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Affiliation(s)
- Joseph R Spangler
- United States Naval Research Laboratory, Center for Biomolecular Science and Engineering, 4555 Overlook Ave SW, Washington, D.C. 20375, United States
| | - Denver N Cooper
- Spelman College, 350 Spelman Ln SW, Atlanta, Georgia 30314, United States
| | - Anthony P Malanoski
- United States Naval Research Laboratory, Center for Biomolecular Science and Engineering, 4555 Overlook Ave SW, Washington, D.C. 20375, United States
| | - Scott A Walper
- United States Naval Research Laboratory, Center for Biomolecular Science and Engineering, 4555 Overlook Ave SW, Washington, D.C. 20375, United States
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9
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Caudal F, Rodrigues S, Dufour A, Artigaud S, Le Blay G, Petek S, Bazire A. Extracts from Wallis Sponges Inhibit Vibrio harveyi Biofilm Formation. Microorganisms 2023; 11:1762. [PMID: 37512934 PMCID: PMC10383632 DOI: 10.3390/microorganisms11071762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 06/29/2023] [Accepted: 07/04/2023] [Indexed: 07/30/2023] Open
Abstract
Pathogenic bacteria and their biofilms are involved in many human and animal diseases and are a major public health problem with, among other things, the development of antibiotic resistance. These biofilms are known to induce chronic infections for which classical treatments using antibiotic therapy are often ineffective. Sponges are sessile filter-feeding marine organisms known for their dynamic symbiotic partnerships with diverse microorganisms and their production of numerous metabolites of interest. In this study, we investigated the antibiofilm efficacy of different extracts from sponges, isolated in Wallis, without biocidal activity. Out of the 47 tested extracts, from 28 different genera, 11 showed a strong activity against Vibrio harveyi biofilm formation. Moreover, one of these extracts also inhibited two quorum-sensing pathways of V. harveyi.
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Affiliation(s)
- Flore Caudal
- Laboratoire de Biotechnologie et Chimie Marines, Université Bretagne Sud, EMR CNRS 6076, IUEM, 56100 Lorient, France
- IRD, Univ Brest, CNRS, Ifremer, LEMAR, F-29280 Plouzane, France
| | - Sophie Rodrigues
- Laboratoire de Biotechnologie et Chimie Marines, Université Bretagne Sud, EMR CNRS 6076, IUEM, 56100 Lorient, France
| | - Alain Dufour
- Laboratoire de Biotechnologie et Chimie Marines, Université Bretagne Sud, EMR CNRS 6076, IUEM, 56100 Lorient, France
| | | | | | - Sylvain Petek
- IRD, Univ Brest, CNRS, Ifremer, LEMAR, F-29280 Plouzane, France
| | - Alexis Bazire
- Laboratoire de Biotechnologie et Chimie Marines, Université Bretagne Sud, EMR CNRS 6076, IUEM, 56100 Lorient, France
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10
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Miller Conrad LC, Perez LJ. A Geneticist Transcribing the Chemical Language of Bacteria. Isr J Chem 2023; 63:e202200079. [PMID: 37469628 PMCID: PMC10353724 DOI: 10.1002/ijch.202200079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Indexed: 12/05/2022]
Abstract
The study of quorum sensing, bacterial cell-to-cell communication mediated by the production and detection of small molecule signals, has skyrocketed since its discovery in the last third of the 20th century. Building from early investigations of bacterial bioluminescence, the process has been characterized to control a numerous and growing number of group behaviors, including virulence and biofilm formation. Bonnie Bassler has made key contributions to the understanding of quorum sensing, leading interdisciplinary efforts to characterize key signaling pathway components and their respective signaling molecules across a range of gram-negative bacteria. This review highlights her work in the field, with a particular emphasis on the chemical contributions of her work.
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Affiliation(s)
- Laura C. Miller Conrad
- Department of Chemistry, San José State University, 1 Washington Sq, San Jose, CA 95192, USA
| | - Lark J. Perez
- Department of Chemistry & Biochemistry, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, USA
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11
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Patel R, Soni M, Soyantar B, Shivangi S, Sutariya S, Saraf M, Goswami D. A clash of quorum sensing vs quorum sensing inhibitors: an overview and risk of resistance. Arch Microbiol 2023; 205:107. [PMID: 36881156 DOI: 10.1007/s00203-023-03442-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 02/08/2023] [Accepted: 02/15/2023] [Indexed: 03/08/2023]
Abstract
Indiscriminate use of antibiotics to treat microbial pathogens has caused emergence of multiple drug resistant strains. Most infectious diseases are caused by microbes that are capable of intercommunication using signaling molecules, which is known as quorum sensing (QS). Such pathogens express their pathogenicity through various QS-regulated virulence factors. Interference of QS could lead to decisive results in controlling such pathogenicity. Hence, QS inhibition has become an attractive new approach for the development of novel drugs. Many quorum sensing inhibitors (QSIs) of diverse origins have been reported. It is imperative that more such anti-QS compounds be found and studied, as they have significant effect on microbial pathogenicity. This review attempts to give a brief account of QS mechanism, its inhibition and describes some compounds with anti-QS potential. Also discussed is the possibility of emergence of quorum sensing resistance.
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Affiliation(s)
- Rohit Patel
- Department of Microbiology and Biotechnology, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, 380009, India
| | - Mansi Soni
- Department of Microbiology and Biotechnology, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, 380009, India
| | - Bilv Soyantar
- Department of Microbiology and Biotechnology, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, 380009, India
| | - Suruchi Shivangi
- Department of Microbiology and Biotechnology, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, 380009, India
| | - Swati Sutariya
- Department of Microbiology and Biotechnology, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, 380009, India
| | - Meenu Saraf
- Department of Microbiology and Biotechnology, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, 380009, India
| | - Dweipayan Goswami
- Department of Microbiology and Biotechnology, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, 380009, India.
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12
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Sanchez S, Ng WL. Motility Control as a Possible Link Between Quorum Sensing to Surface Attachment in Vibrio Species. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1404:65-75. [PMID: 36792871 DOI: 10.1007/978-3-031-22997-8_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
In this chapter, we discuss motility control as a possible link between quorum sensing (QS) to surface attachment in Vibrio species. QS regulates a variety of behaviors that are important for the life cycle of many bacterial species, including virulence factor production, biofilm formation, or metabolic homeostasis. Therefore, without QS, many species of bacteria cannot survive in their natural environments. Here, we summarize several QS systems in different Vibrio species and discuss some of emerging features that suggest QS is intimately connected to motility control. Finally, we speculate the connection between motility and QS is critical for Vibrio species to detect solid surfaces for surface attachment.
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Affiliation(s)
- Sandra Sanchez
- Department of Molecular Biology and Microbiology, School of Medicine, Tufts University, Boston, MA, USA
| | - Wai-Leung Ng
- Department of Molecular Biology and Microbiology, School of Medicine, Tufts University, Boston, MA, USA.
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13
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Collective decision-making in Pseudomonas aeruginosa involves transient segregation of quorum-sensing activities across cells. Curr Biol 2022; 32:5250-5261.e6. [PMID: 36417904 DOI: 10.1016/j.cub.2022.10.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/07/2022] [Accepted: 10/25/2022] [Indexed: 11/23/2022]
Abstract
A hallmark of bacterial sociality is that groups can coordinate cooperative actions through a cell-to-cell communication process called quorum sensing (QS). QS regulates key bacterial phenotypes such as virulence in infections and digestion of extracellular compounds in the environment. Although QS responses are typically studied as group-level phenotypes, it is unclear whether individuals coordinate their actions at the single-cell level or whether group phenotypes simply reflect the sum of their noisy members. Here, we studied the behavior of Pseudomonas aeruginosa individuals by tracking their temporal commitments to the two intertwined Las and Rhl-QS systems, from low to high population density. Using chromosomally integrated fluorescent gene reporters, we found that QS gene expression (signal, receptor, and cooperative exoproduct) was noisy with heterogeneity peaking during the build-up phase of QS. Moreover, we observed the formation of discrete subgroups of cells that transiently segregate into two gene expression states: low Las-receptor expressers that instantly activate exoproduct production and high Las-receptor expressers with delayed exoproduct production. Later, gene expression activities converged with all cells fully committing to QS. We developed general mathematical models to show that gene expression segregation can mechanistically be spurred by molecular resource limitations during the initiation phase of regulatory cascades such as QS. Moreover, our models indicate that gene expression segregation across cells can operate as a built-in brake enabling a temporary bet-hedging strategy in unpredictable environments. Altogether, our work reveals that studying the behavior of bacterial individuals is key to understanding emergent collective actions at the group level.
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14
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An RNA sponge controls quorum sensing dynamics and biofilm formation in Vibrio cholerae. Nat Commun 2022; 13:7585. [PMID: 36482060 PMCID: PMC9732341 DOI: 10.1038/s41467-022-35261-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 11/24/2022] [Indexed: 12/13/2022] Open
Abstract
Small regulatory RNAs (sRNAs) acting in concert with the RNA chaperone Hfq are prevalent in many bacteria and typically act by base-pairing with multiple target transcripts. In the human pathogen Vibrio cholerae, sRNAs play roles in various processes including antibiotic tolerance, competence, and quorum sensing (QS). Here, we use RIL-seq (RNA-interaction-by-ligation-and-sequencing) to identify Hfq-interacting sRNAs and their targets in V. cholerae. We find hundreds of sRNA-mRNA interactions, as well as RNA duplexes formed between two sRNA regulators. Further analysis of these duplexes identifies an RNA sponge, termed QrrX, that base-pairs with and inactivates the Qrr1-4 sRNAs, which are known to modulate the QS pathway. Transcription of qrrX is activated by QrrT, a previously uncharacterized LysR-type transcriptional regulator. Our results indicate that QrrX and QrrT are required for rapid conversion from individual to community behaviours in V. cholerae.
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15
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Bernabè G, Marzaro G, Di Pietra G, Otero A, Bellato M, Pauletto A, Scarpa M, Sut S, Chilin A, Dall’Acqua S, Brun P, Castagliuolo I. A novel phenolic derivative inhibits AHL-dependent quorum sensing signaling in Pseudomonas aeruginosa. Front Pharmacol 2022; 13:996871. [PMID: 36204236 PMCID: PMC9531014 DOI: 10.3389/fphar.2022.996871] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/05/2022] [Indexed: 11/13/2022] Open
Abstract
Increasing antibiotic resistance and the decline in the pharmaceutical industry’s investments have amplified the need for novel treatments for multidrug-resistant bacteria. Quorum sensing (QS) inhibitors reduce pathogens’ virulence without selective pressure on bacteria and provide an alternative to conventional antibiotic-based therapies. P. aeruginosa uses complex QS signaling to control virulence and biofilm formation. We aimed to identify inhibitors of P. aeruginosa QS acting on acyl-homoserine lactones (AHL)-mediated circuits. Bioluminescence and qRT-PCR assays were employed to screen a library of 81 small phenolic derivatives to reduce AHL-dependent signaling. We identified GM-50 as the most active compound inhibiting the expression of AHL-regulated genes but devoid of cytotoxic activity in human epithelial cells and biocidal effects on bacteria. GM-50 reduces virulence factors such as rhamnolipids, pyocyanin, elastase secretion, and swarming motility in P. aeruginosa PAO1 laboratory strain. By molecular docking, we provide evidence that GM-50 highly interacts with RhlR. GM-50 significantly improved aztreonam-mediated biofilm disruption. Moreover, GM-50 prevents adhesion of PAO1 and inflammatory damage in the human A549 cell line and protects Galleria mellonella from PAO1-mediated killing. GM-50 significantly reduces virulence factors in 20 P. aeruginosa clinical isolates from patients with respiratory tract infections. In conclusion, GM-50 inhibits AHL-signaling, reduces virulence factors, enhances the anti-biofilm activity of aztreonam, and protects G. mellonella larvae from damage induced by P. aeruginosa. Since GM-50 is active on clinical strains, it represents a starting point for identifying and developing new phenolic derivatives acting as QS-inhibitors in P. aeruginosa infections.
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Affiliation(s)
- Giulia Bernabè
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | - Giovanni Marzaro
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | | | - Ana Otero
- Departamento de Microbioloxía e Parasitoloxía, Facultade de Bioloxía-CIBUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Massimo Bellato
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Anthony Pauletto
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | - Melania Scarpa
- Laboratory of Advanced Translational Research, Veneto Institute of Oncology IOV—IRCCS, Padua, Italy
| | - Stefania Sut
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Adriana Chilin
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Stefano Dall’Acqua
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Paola Brun
- Department of Molecular Medicine, University of Padua, Padua, Italy
- *Correspondence: Paola Brun,
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16
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Host–Bacterial Interactions: Outcomes of Antimicrobial Peptide Applications. MEMBRANES 2022; 12:membranes12070715. [PMID: 35877918 PMCID: PMC9317001 DOI: 10.3390/membranes12070715] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 02/04/2023]
Abstract
The bacterial membrane is part of a secretion system which plays an integral role to secrete proteins responsible for cell viability and pathogenicity; pathogenic bacteria, for example, secrete virulence factors and other membrane-associated proteins to invade the host cells through various types of secretion systems (Type I to Type IX). The bacterial membrane can also mediate microbial communities’ communication through quorum sensing (QS), by secreting auto-stimulants to coordinate gene expression. QS plays an important role in regulating various physiological processes, including bacterial biofilm formation while providing increased virulence, subsequently leading to antimicrobial resistance. Multi-drug resistant (MDR) bacteria have emerged as a threat to global health, and various strategies targeting QS and biofilm formation have been explored by researchers worldwide. Since the bacterial secretion systems play such a crucial role in host–bacterial interactions, this review intends to outline current understanding of bacterial membrane systems, which may provide new insights for designing approaches aimed at antimicrobials discovery. Various mechanisms pertaining interaction of the bacterial membrane with host cells and antimicrobial agents will be highlighted, as well as the evolution of bacterial membranes in evasion of antimicrobial agents. Finally, the use of antimicrobial peptides (AMPs) as a cellular device for bacterial secretion systems will be discussed as emerging potential candidates for the treatment of multidrug resistance infections.
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17
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Sionov RV, Steinberg D. Targeting the Holy Triangle of Quorum Sensing, Biofilm Formation, and Antibiotic Resistance in Pathogenic Bacteria. Microorganisms 2022; 10:1239. [PMID: 35744757 PMCID: PMC9228545 DOI: 10.3390/microorganisms10061239] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 06/12/2022] [Accepted: 06/14/2022] [Indexed: 12/12/2022] Open
Abstract
Chronic and recurrent bacterial infections are frequently associated with the formation of biofilms on biotic or abiotic materials that are composed of mono- or multi-species cultures of bacteria/fungi embedded in an extracellular matrix produced by the microorganisms. Biofilm formation is, among others, regulated by quorum sensing (QS) which is an interbacterial communication system usually composed of two-component systems (TCSs) of secreted autoinducer compounds that activate signal transduction pathways through interaction with their respective receptors. Embedded in the biofilms, the bacteria are protected from environmental stress stimuli, and they often show reduced responses to antibiotics, making it difficult to eradicate the bacterial infection. Besides reduced penetration of antibiotics through the intricate structure of the biofilms, the sessile biofilm-embedded bacteria show reduced metabolic activity making them intrinsically less sensitive to antibiotics. Moreover, they frequently express elevated levels of efflux pumps that extrude antibiotics, thereby reducing their intracellular levels. Some efflux pumps are involved in the secretion of QS compounds and biofilm-related materials, besides being important for removing toxic substances from the bacteria. Some efflux pump inhibitors (EPIs) have been shown to both prevent biofilm formation and sensitize the bacteria to antibiotics, suggesting a relationship between these processes. Additionally, QS inhibitors or quenchers may affect antibiotic susceptibility. Thus, targeting elements that regulate QS and biofilm formation might be a promising approach to combat antibiotic-resistant biofilm-related bacterial infections.
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Affiliation(s)
- Ronit Vogt Sionov
- The Biofilm Research Laboratory, The Institute of Biomedical and Oral Research, The Faculty of Dental Medicine, Hadassah Medical School, The Hebrew University, Jerusalem 9112102, Israel;
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18
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Role of microalgal metabolites in controlling quorum-sensing-regulated biofilm. Arch Microbiol 2022; 204:163. [PMID: 35119531 DOI: 10.1007/s00203-022-02776-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 11/02/2022]
Abstract
Bacterial infections are primarily caused due to the formation of biofilms on the surfaces. The formation of bacterial biofilms results in 60-70% of nosocomial infections in hospital-acquired infections for multidrug-resistant bacteria. Quorum-sensing (QS) is the process of cell-cell communications among bacterial cells. The formation and regulation of biofilm-producing signaling molecules, competence for DNA uptake and factors responsible for virulence occur. When the bacterial cell population density increases, auto-inducers bind with QS receptors and induce gene expression. To suppress the expression of the virulence genes, certain antibiotics and small molecules are used against the pathogenic bacteria. Since the microorganisms are becoming resistant to antibiotics, there is a need of new compounds or molecules which can suppress or inhibit the expression or regulation of virulence genes. Microalgae are an important and rich source of bioactive compounds which have the antimicrobial property. Microalgae have various antibacterial metabolites, such as Portoamides (peptides), flavonoids, eicosapentaenoic acid, alkaloids, peptides and many other secondary metabolites. This review focuses on the signaling molecule-regulated QS mechanism, biofilm formation, and microalgae compounds' effects against pathogenic bacteria. Consequently, most of the compounds have made it to the different levels of clinical trials, even some of the compounds are used therapeutically. Despite the promising applications of antibacterial peptides and the importance of searching for new natural sources of antibiotics, limitations persist for their pharmaceutical applications. However, given due research impetus, these marine metabolites might emerge as a new wave of promising drugs.
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19
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Fan Q, Wang H, Mao C, Li J, Zhang X, Grenier D, Yi L, Wang Y. Structure and Signal Regulation Mechanism of Interspecies and Interkingdom Quorum Sensing System Receptors. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:429-445. [PMID: 34989570 DOI: 10.1021/acs.jafc.1c04751] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Quorum sensing (QS) is a signaling mechanism for cell-to-cell communication between bacteria, fungi, and even eukaryotic hosts such as plant and animal cells. Bacteria in real life do not exist as isolated organisms but are found in complex, dynamic, and microecological environments. The study of interspecies QS and interkingdom QS is a valuable approach for exploring bacteria-bacteria interactions and bacteria-host interaction mechanisms and has received considerable attention from researchers. The correct combination of QS signals and receptors is key to initiating the QS process. Compared with intraspecies QS, the signal regulation mechanism of interspecies QS and interkingdom QS is often more complicated, and the distribution of receptors is relatively wide. The present review focuses on the latest progress with respect to the distribution, structure, and signal transduction of interspecies and interkingdom QS receptors and provides a guide for the investigation of new QS receptors in the future.
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Affiliation(s)
- Qingying Fan
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China
- Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang 471000, China
| | - Haikun Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China
- Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang 471000, China
| | - Chenlong Mao
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China
- Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang 471000, China
| | - Jinpeng Li
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China
- Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang 471000, China
| | - Xiaoling Zhang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China
- Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang 471000, China
| | - Daniel Grenier
- Groupe de Recherche en Écologie Buccale (GREB), Faculté de Médecine Dentaire, Université Laval, Quebec City, Quebec G1 V 0A6, Canada
| | - Li Yi
- College of Life Science, Luoyang Normal University, Luoyang 471023, China
| | - Yang Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China
- Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang 471000, China
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20
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Piatek P, Humphreys C, Raut MP, Wright PC, Simpson S, Köpke M, Minton NP, Winzer K. Agr Quorum Sensing influences the Wood-Ljungdahl pathway in Clostridium autoethanogenum. Sci Rep 2022; 12:411. [PMID: 35013405 PMCID: PMC8748961 DOI: 10.1038/s41598-021-03999-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 12/07/2021] [Indexed: 01/04/2023] Open
Abstract
Acetogenic bacteria are capable of fermenting CO2 and carbon monoxide containing waste-gases into a range of platform chemicals and fuels. Despite major advances in genetic engineering and improving these biocatalysts, several important physiological functions remain elusive. Among these is quorum sensing, a bacterial communication mechanism known to coordinate gene expression in response to cell population density. Two putative agr systems have been identified in the genome of Clostridium autoethanogenum suggesting bacterial communication via autoinducing signal molecules. Signal molecule-encoding agrD1 and agrD2 genes were targeted for in-frame deletion. During heterotrophic growth on fructose as a carbon and energy source, single deletions of either gene did not produce an observable phenotype. However, when both genes were simultaneously inactivated, final product concentrations in the double mutant shifted to a 1.5:1 ratio of ethanol:acetate, compared to a 0.2:1 ratio observed in the wild type control, making ethanol the dominant fermentation product. Moreover, CO2 re-assimilation was also notably reduced in both hetero- and autotrophic growth conditions. These findings were supported through comparative proteomics, which showed lower expression of carbon monoxide dehydrogenase, formate dehydrogenase A and hydrogenases in the ∆agrD1∆agrD2 double mutant, but higher levels of putative alcohol and aldehyde dehydrogenases and bacterial micro-compartment proteins. These findings suggest that Agr quorum sensing, and by inference, cell density play a role in carbon resource management and use of the Wood-Ljungdahl pathway as an electron sink.
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Affiliation(s)
- Pawel Piatek
- Department of Biotechnology and Nanomedicine, SINTEF Industry, 7465, Trondheim, Norway
- BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University Park, The University of Nottingham, Nottingham, UK
| | - Christopher Humphreys
- BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University Park, The University of Nottingham, Nottingham, UK
| | - Mahendra P Raut
- Department of Chemical and Biological Engineering, The ChELSI Institute, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - Phillip C Wright
- University of Southampton, University Road, Southampton, SO17 1BJ, UK
| | - Sean Simpson
- LanzaTech Inc., 8045 Lamon Ave, Suite 400, Skokie, IL, 60077, USA
| | - Michael Köpke
- LanzaTech Inc., 8045 Lamon Ave, Suite 400, Skokie, IL, 60077, USA
| | - Nigel P Minton
- BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University Park, The University of Nottingham, Nottingham, UK
| | - Klaus Winzer
- BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University Park, The University of Nottingham, Nottingham, UK.
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21
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Li J, Fan Q, Jin M, Mao C, Zhang H, Zhang X, Sun L, Grenier D, Yi L, Hou X, Wang Y. Paeoniflorin reduce luxS/AI-2 system-controlled biofilm formation and virulence in Streptococcus suis. Virulence 2021; 12:3062-3073. [PMID: 34923916 PMCID: PMC8923065 DOI: 10.1080/21505594.2021.2010398] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Streptococcus suis (S. suis), more specifically serotype 2, is a bacterial pathogen that threatens the lives of pigs and humans. Like many other pathogens, S. suis exhibits quorum sensing (QS) system-controlled virulence factors, such as biofilm formation that complicates treatment. Therefore, impairing the QS involving LuxS/AI-2 cycle in S. suis, may be a promising alternative strategy for overcoming S. suis infections. In this study, we investigated paeoniflorin (PF), a monoterpenoid glycoside compound extracted from peony, as an inhibitor of S. suis LuxS/AI-2 system. At a sub-minimal inhibitory concentration (MIC) (1/16 MIC; 25 μg/ml), PF significantly reduced biofilm formation by S. suis through inhibition of extracellular polysaccharide (EPS) production, without affecting bacterial growth. Moreover, evidence was brought that PF reduces AI-2 activity in S. suis biofilm. Molecular docking indicated that LuxS may be the target of PF. Monitoring LuxS enzymatic activity confirmed that PF had a partial inhibitory effect. Finally, we showed that the use of PF in a mouse model can relieve S. suis infections. This study highlighted the anti-biofilm potential of PF against S. suis, and brought evidence that it may as an inhibitor of the LuxS/AI-2 system to prevent S. suis biofilm-related infections. PF can thus be used as a new type of natural biofilm inhibitor for clinical application.
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Affiliation(s)
- Jinpeng Li
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China.,Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
| | - Qingying Fan
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China.,Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
| | - Manyu Jin
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China.,Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
| | - Chenlong Mao
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China.,Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
| | - Hui Zhang
- China Animal Health and Epidemiology Center, Qingdao, China
| | - Xiaoling Zhang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China.,Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
| | - Liyun Sun
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China.,Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
| | - Daniel Grenier
- Groupe de Recherche En Écologie Buccale (Greb), Faculté de Médecine Dentaire, Université Laval, Quebec City, Canada
| | - Li Yi
- Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China.,College of Life Science, Luoyang Normal University, Luoyang, China
| | - Xiaogai Hou
- College of Agriculture/College of Tree Peony, Henan University of Science and Technology Luoyang China
| | - Yang Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China.,Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
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22
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Gao C, Garren M, Penn K, Fernandez VI, Seymour JR, Thompson JR, Raina JB, Stocker R. Coral mucus rapidly induces chemokinesis and genome-wide transcriptional shifts toward early pathogenesis in a bacterial coral pathogen. THE ISME JOURNAL 2021; 15:3668-3682. [PMID: 34168314 PMCID: PMC8630044 DOI: 10.1038/s41396-021-01024-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 05/12/2021] [Accepted: 05/25/2021] [Indexed: 02/06/2023]
Abstract
Elevated seawater temperatures have contributed to the rise of coral disease mediated by bacterial pathogens, such as the globally distributed Vibrio coralliilyticus, which utilizes coral mucus as a chemical cue to locate stressed corals. However, the physiological events in the pathogens that follow their entry into the coral host environment remain unknown. Here, we present simultaneous measurements of the behavioral and transcriptional responses of V. coralliilyticus BAA-450 incubated in coral mucus. Video microscopy revealed a strong and rapid chemokinetic behavioral response by the pathogen, characterized by a two-fold increase in average swimming speed within 6 min of coral mucus exposure. RNA sequencing showed that this bacterial behavior was accompanied by an equally rapid differential expression of 53% of the genes in the V. coralliilyticus genome. Specifically, transcript abundance 10 min after mucus exposure showed upregulation of genes involved in quorum sensing, biofilm formation, and nutrient metabolism, and downregulation of flagella synthesis and chemotaxis genes. After 60 min, we observed upregulation of genes associated with virulence, including zinc metalloproteases responsible for causing coral tissue damage and algal symbiont photoinactivation, and secretion systems that may export toxins. Together, our results suggest that V. coralliilyticus employs a suite of behavioral and transcriptional responses to rapidly shift into a distinct infection mode within minutes of exposure to the coral microenvironment.
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Affiliation(s)
- Cherry Gao
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Civil and Environmental Engineering, Ralph M. Parsons Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, Zurich, Switzerland
| | - Melissa Garren
- Working Ocean Strategies LLC, Carmel, CA, USA
- Department of Applied Environmental Science, California State University Monterey Bay, Seaside, CA, USA
| | - Kevin Penn
- Department of Civil and Environmental Engineering, Ralph M. Parsons Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Vicente I Fernandez
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, Zurich, Switzerland
| | - Justin R Seymour
- Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, Australia
| | - Janelle R Thompson
- Singapore Center for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- Asian School of the Environment, Nanyang Technological University, Singapore, Singapore
| | - Jean-Baptiste Raina
- Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, Australia
| | - Roman Stocker
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, Zurich, Switzerland.
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23
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Quorum Sensing Regulation of Virulence Gene Expression in Vibrio harveyi during its Interaction with Marine Diatom Skeletonema marinoi. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2021. [DOI: 10.22207/jpam.15.4.78] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Communication between species from different kingdoms may be as important as intra-kingdom communication. It has recently been confirmed that co-existing bacteria and phytoplankton in aquatic ecosystems do cross-talk. This study examined the signs of possible cross signalling between V. harveyi, one of the predominant bacterial species of the marine ecosystem and a dominant diatom species, S.marinoi, to understand communication over species borders. It is known that V.harveyi employ quorum sensing for cell-to-cell communication, bioluminescence (luxR), and the regulation of the virulence gene (vhp, chiA). Former studies have also shown, this kind of interactions being disrupted by compounds secreted by a few algal species existing in the aquatic ecosystem. We investigated the QS communication by quantifying the expression levels of virulence regulator luxR and virulence factors metalloprotease (vhp) and chitinase (chiA) in four different V. harveyi strains grown in the presence of S. marinoi strain. Results obtained in this study indicate that quorum sensing was activated in strains of V. harveyi analysed but did not regulate the expressions of vhp and chiA virulence factors. This observation suggests that the existence of S. marinoi did not interfere with the QS behaviour of V. harveyi and its interaction with marine diatom; it may be due to the commensalism relationship.
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24
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Gao R, Helfant LJ, Wu T, Li Z, Brokaw SE, Stock AM. A balancing act in transcription regulation by response regulators: titration of transcription factor activity by decoy DNA binding sites. Nucleic Acids Res 2021; 49:11537-11549. [PMID: 34669947 PMCID: PMC8599769 DOI: 10.1093/nar/gkab935] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 09/13/2021] [Accepted: 09/28/2021] [Indexed: 11/30/2022] Open
Abstract
Studies of transcription regulation are often focused on binding of transcription factors (TFs) to a small number of promoters of interest. It is often assumed that TFs are in great excess to their binding sites (TFBSs) and competition for TFs between DNA sites is seldom considered. With increasing evidence that TFBSs are exceedingly abundant for many TFs and significant variations in TF and TFBS numbers occur during growth, the interplay between a TF and all TFBSs should not be ignored. Here, we use additional decoy DNA sites to quantitatively analyze how the relative abundance of a TF to its TFBSs impacts the steady-state level and onset time of gene expression for the auto-activated Escherichia coli PhoB response regulator. We show that increasing numbers of decoy sites progressively delayed transcription activation and lowered promoter activities. Perturbation of transcription regulation by additional TFBSs did not require extreme numbers of decoys, suggesting that PhoB is approximately at capacity for its DNA sites. Addition of decoys also converted a graded response to a bi-modal response. We developed a binding competition model that captures the major features of experimental observations, providing a quantitative framework to assess how variations in TFs and TFBSs influence transcriptional responses.
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Affiliation(s)
- Rong Gao
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University - Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
| | - Libby J Helfant
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University - Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
| | - Ti Wu
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University - Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
| | - Zeyue Li
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University - Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
| | - Samantha E Brokaw
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University - Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
| | - Ann M Stock
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University - Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
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25
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Coquant G, Aguanno D, Pham S, Grellier N, Thenet S, Carrière V, Grill JP, Seksik P. Gossip in the gut: Quorum sensing, a new player in the host-microbiota interactions. World J Gastroenterol 2021; 27:7247-7270. [PMID: 34876787 PMCID: PMC8611211 DOI: 10.3748/wjg.v27.i42.7247] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 08/17/2021] [Accepted: 10/27/2021] [Indexed: 02/06/2023] Open
Abstract
Bacteria are known to communicate with each other and regulate their activities in social networks by secreting and sensing signaling molecules called autoinducers, a process known as quorum sensing (QS). This is a growing area of research in which we are expanding our understanding of how bacteria collectively modify their behavior but are also involved in the crosstalk between the host and gut microbiome. This is particularly relevant in the case of pathologies associated with dysbiosis or disorders of the intestinal ecosystem. This review will examine the different QS systems and the evidence for their presence in the intestinal ecosystem. We will also provide clues on the role of QS molecules that may exert, directly or indirectly through their bacterial gossip, an influence on intestinal epithelial barrier function, intestinal inflammation, and intestinal carcinogenesis. This review aims to provide evidence on the role of QS molecules in gut physiology and the potential shared by this new player. Better understanding the impact of intestinal bacterial social networks and ultimately developing new therapeutic strategies to control intestinal disorders remains a challenge that needs to be addressed in the future.
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Affiliation(s)
- Garance Coquant
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
| | - Doriane Aguanno
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
- EPHE, PSL University, Paris 75014, France
| | - Sandrine Pham
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
- EPHE, PSL University, Paris 75014, France
| | - Nathan Grellier
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
| | - Sophie Thenet
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
- EPHE, PSL University, Paris 75014, France
| | - Véronique Carrière
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
| | - Jean-Pierre Grill
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
| | - Philippe Seksik
- Centre de Recherche Saint-Antoine, INSERM, Sorbonne Université, Paris 75012, France
- Department of Gastroenterology and Nutrition, Saint-Antoine Hospital, APHP, Paris 75012, France
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26
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Dimension-reduction simplifies the analysis of signal crosstalk in a bacterial quorum sensing pathway. Sci Rep 2021; 11:19719. [PMID: 34611201 PMCID: PMC8492804 DOI: 10.1038/s41598-021-99169-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 09/21/2021] [Indexed: 11/16/2022] Open
Abstract
Many pheromone sensing bacteria produce and detect more than one chemically distinct signal, or autoinducer. The pathways that detect these signals are typically noisy and interlocked through crosstalk and feedback. As a result, the sensing response of individual cells is described by statistical distributions that change under different combinations of signal inputs. Here we examine how signal crosstalk reshapes this response. We measure how combinations of two homoserine lactone (HSL) input signals alter the statistical distributions of individual cell responses in the AinS/R- and LuxI/R-controlled branches of the Vibrio fischeri bioluminescence pathway. We find that, while the distributions of pathway activation in individual cells vary in complex fashion with environmental conditions, these changes have a low-dimensional representation. For both the AinS/R and LuxI/R branches, the distribution of individual cell responses to mixtures of the two HSLs is effectively one-dimensional, so that a single tuning parameter can capture the full range of variability in the distributions. Combinations of crosstalking HSL signals extend the range of responses for each branch of the circuit, so that signals in combination allow population-wide distributions that are not available under a single HSL input. Dimension reduction also simplifies the problem of identifying the HSL conditions to which the pathways and their outputs are most sensitive. A comparison of the maximum sensitivity HSL conditions to actual HSL levels measured during culture growth indicates that the AinS/R and LuxI/R branches lack sensitivity to population density except during the very earliest and latest stages of growth respectively.
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27
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Naser IB, Shishir TA, Faruque SN, Hoque MM, Hasan A, Faruque SM. Environmental prevalence of toxigenic Vibrio cholerae O1 in Bangladesh coincides with V. cholerae non-O1 non-O139 genetic variants which overproduce autoinducer-2. PLoS One 2021; 16:e0254068. [PMID: 34214115 PMCID: PMC8253391 DOI: 10.1371/journal.pone.0254068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 06/19/2021] [Indexed: 12/02/2022] Open
Abstract
Prevalence of toxigenic Vibrio cholerae O1 in aquatic reservoirs in Bangladesh apparently increases coinciding with the occurrence of seasonal cholera epidemics. In between epidemics, these bacteria persist in water mostly as dormant cells, known as viable but non-culturable cells (VBNC), or conditionally viable environmental cells (CVEC), that fail to grow in routine culture. CVEC resuscitate to active cells when enriched in culture medium supplemented with quorum sensing autoinducers CAI-1 or AI-2 which are signal molecules that regulate gene expression dependent on cell density. V. cholerae O1 mutant strains with inactivated cqsS gene encoding the CAI-1 receptor has been shown to overproduce AI-2 that enhance CVEC resuscitation in water samples. Since V. cholerae non-O1 non-O139 (non-cholera-vibrios) are abundant in aquatic ecosystems, we identified and characterized naturally occurring variant strains of V. cholerae non-O1 non-O139 which overproduce AI-2, and monitored their co-occurrence with V. cholerae O1 in water samples. The nucleotide sequence and predicted protein products of the cqsS gene carried by AI-2 overproducing variant strains showed divergence from that of typical V. cholerae O1 or non-O1 strains, and their culture supernatants enhanced resuscitation of CVEC in water samples. Furthermore, prevalence of V. cholerae O1 in the aquatic environment was found to coincide with an increase in AI-2 overproducing non-O1 non-O139 strains. These results suggest a possible role of non-cholera vibrios in the environmental biology of the cholera pathogen, in which non-O1 non-O139 variant strains overproducing AI-2 presumably contribute in resuscitation of the latent pathogen, leading to seasonal cholera epidemics. Importance. Toxigenic Vibrio cholerae which causes seasonal epidemics of cholera persists in aquatic reservoirs in endemic areas. The bacteria mostly exist in a dormant state during inter-epidemic periods, but periodically resuscitate to the active form. The resuscitation is enhanced by signal molecules called autoinducers (AIs). Toxigenic V. cholerae can be recovered from water samples that normally test negative for the organism in conventional culture, by supplementing the culture medium with exogenous AIs. V. cholerae belonging to the non-O1 non-O139 serogroups which do not cause cholera are also abundant in natural waters, and they are capable of producing AIs. In this study we characterized V. cholerae non-O1 non-O139 variant strains which overproduce an autoinducer called AI-2, and found that the abundance of the cholera pathogen in aquatic reservoirs correlates with an increase in the AI-2 overproducing strains. Our results suggest a probable role of these variant strains in the environmental biology and epidemiology of toxigenic V. cholerae, and may lead to novel means for surveillance, prevention and control of cholera.
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Affiliation(s)
- Iftekhar Bin Naser
- School of Environment and Life Sciences, Independent University Bangladesh, Bashundhara, Dhaka, Bangladesh
- Department of Mathematics and Natural Sciences, BRAC University, Dhaka, Bangladesh
- Laboratory Sciences and Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Tushar Ahmed Shishir
- Department of Mathematics and Natural Sciences, BRAC University, Dhaka, Bangladesh
| | - Shah Nayeem Faruque
- Department of Biochemistry and Microbiology, North South University, Dhaka, Bangladesh
| | - M. Mozammel Hoque
- Laboratory Sciences and Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Anamul Hasan
- Laboratory Sciences and Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Shah M. Faruque
- School of Environment and Life Sciences, Independent University Bangladesh, Bashundhara, Dhaka, Bangladesh
- Laboratory Sciences and Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
- * E-mail: ,
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28
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Bruger EL, Snyder DJ, Cooper VS, Waters CM. Quorum sensing provides a molecular mechanism for evolution to tune and maintain investment in cooperation. THE ISME JOURNAL 2021; 15:1236-1247. [PMID: 33342998 PMCID: PMC8115533 DOI: 10.1038/s41396-020-00847-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 10/22/2020] [Accepted: 11/16/2020] [Indexed: 01/29/2023]
Abstract
As selection frequently favors noncooperating defectors in mixed populations with cooperators, mechanisms that promote cooperation stability clearly exist. One potential mechanism is bacterial cell-to-cell communication, quorum sensing (QS), which can allow cooperators to prevent invasion by defectors. However, the impact of QS on widespread maintenance of cooperation in well-mixed conditions has not been experimentally demonstrated over extended evolutionary timescales. Here, we use wild-type (WT) Vibrio campbellii that regulates cooperation with QS and an unconditional cooperating (UC) mutant to examine the evolutionary origins and dynamics of novel defectors during a long-term evolution experiment. We found that UC lineages were completely outcompeted by defectors, whereas functioning QS enabled the maintenance of cooperative variants in most WT populations. Sequencing evolved populations revealed multiple luxR mutations that swept the UC lineages. However, the evolution of mutant lineages with reduced levels of bioluminescence (dims) occurred in many WT lineages. These dim variants also decreased other cooperative phenotypes regulated by QS, including protease production, indicating they result from changes to QS regulation. This diminished investment phenotype optimizes a tradeoff between cooperative input and growth output and suggests that decreasing the cost of QS could be a favorable strategy for maintaining the cooperative behaviors it regulates.
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Affiliation(s)
- Eric L. Bruger
- grid.266456.50000 0001 2284 9900Department of Biological Sciences, University of Idaho, Moscow, ID USA ,grid.266456.50000 0001 2284 9900Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, ID USA ,grid.266456.50000 0001 2284 9900Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID USA ,grid.17088.360000 0001 2150 1785The BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI USA
| | - Daniel J. Snyder
- grid.21925.3d0000 0004 1936 9000Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA USA
| | - Vaughn S. Cooper
- grid.21925.3d0000 0004 1936 9000Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA USA
| | - Christopher M. Waters
- grid.17088.360000 0001 2150 1785The BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI USA ,grid.17088.360000 0001 2150 1785Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI USA
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29
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Liang X, Chen QY, Seabra GM, Matthew S, Kwan JC, Li C, Paul VJ, Luesch H. Bifunctional Doscadenamides Activate Quorum Sensing in Gram-Negative Bacteria and Synergize with TRAIL to Induce Apoptosis in Cancer Cells. JOURNAL OF NATURAL PRODUCTS 2021; 84:779-789. [PMID: 33480689 PMCID: PMC8209783 DOI: 10.1021/acs.jnatprod.0c01003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
New cyanobacteria-derived bifunctional analogues of doscadenamide A, a LasR-dependent quorum sensing (QS) activator in Pseudomonas aeruginosa, characterized by dual acylation of the pyrrolinone core structure and the pendant side chain primary amine to form an imide/amide hybrid are reported. The identities of doscadenamides B-J were confirmed through total synthesis and a strategic focused library with different acylation and unsaturation patterns was created. Key molecular interactions for binding with LasR and a functional response through mutation studies coupled with molecular docking were identified. The structure-activity relationships (SARs) were probed in various Gram-negative bacteria, including P. aeruginosa and Vibrio harveyi, indicating that the pyrrolinone-N acyl chain is critical for full agonist activity, while the other acyl chain is dispensable or can result in antagonist activity, depending on the bacterial system. Since homoserine lactone (HSL) quorum sensing activators have been shown to act in synergy with TRAIL to induce apoptosis in cancer cells, selected doscadenamides were tested in orthogonal eukaryotic screening systems. The most potent QS agonists, doscadenamides S10-S12, along with doscadenamides F and S4 with partial or complete saturation of the acyl side chains, exhibited the most pronounced synergistic effects with TRAIL in triple negative MDA-MB-231 breast cancer cells. The overall correlation of the SAR with respect to prokaryotic and eukaryotic targets may hint at coevolutionary processes and intriguing host-bacteria relationships. The doscadenamide scaffold represents a non-HSL template for combination therapy with TRAIL pathway stimulators.
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Affiliation(s)
- Xiao Liang
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
- Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, Florida 32610, United States
| | - Qi-Yin Chen
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
- Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, Florida 32610, United States
| | - Gustavo M. Seabra
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
- Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, Florida 32610, United States
| | - Susan Matthew
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
| | - Jason C. Kwan
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
| | - Chenglong Li
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
- Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, Florida 32610, United States
| | - Valerie J. Paul
- Smithsonian Marine Station, Fort Pierce, Florida 34949, United States
| | - Hendrik Luesch
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
- Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, Florida 32610, United States
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30
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Chang SC, Lee CY. Quorum-Sensing Regulator OpaR Directly Represses Seven Protease Genes in Vibrio parahaemolyticus. Front Microbiol 2020; 11:534692. [PMID: 33193123 PMCID: PMC7658014 DOI: 10.3389/fmicb.2020.534692] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 10/08/2020] [Indexed: 01/25/2023] Open
Abstract
Proteases play a key role in numerous bacterial physiological events. Microbial proteases are used in the pharmaceutical industry and in biomedical applications. The genus Vibrio comprises protease-producing bacteria. Proteases transform polypeptides into shorter chains for easier utilization. They also function as a virulence factor in pathogens. The mechanism by which protease genes are regulated in Vibrio parahaemolyticus, an emerging world-wide human pathogen, however, still remains unclear. Quorum sensing is the communication system of bacteria. OpaR is the master quorum-sensing regulator in V. parahaemolyticus. In the present study, quantitative reverse transcriptase-polymerase chain reaction and protease gene promoter-fusion reporter assays revealed that OpaR represses seven protease genes—three metalloprotease genes and four serine protease genes—which are involved in environmental survival and bacterial virulence. Furthermore, the electrophoresis mobility shift assay demonstrated that OpaR is bound directly to the promoter region of each of the seven protease genes. DNase I footprinting identified the sequence of these OpaR-binding sites. ChIP-seq analyses revealed 435 and 835 OpaR-binding sites in the late-log and stationary phases, respectively. These OpaR-binding sequences indicated a conserved OpaR-binding motif: TATTGATAAAATTATCAATA. These results advance our understanding of the protease regulation system in V. parahaemolyticus. This study is the first to reveal the OpaR motif within V. parahaemolyticus in vivo, using ChIP-seq, and to provide a database for OpaR direct regulon.
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Affiliation(s)
- San-Chi Chang
- Microbiology Laboratory, Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan
| | - Chia-Yin Lee
- Microbiology Laboratory, Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan
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31
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Fernandez NL, Hsueh BY, Nhu NTQ, Franklin JL, Dufour YS, Waters CM. Vibrio cholerae adapts to sessile and motile lifestyles by cyclic di-GMP regulation of cell shape. Proc Natl Acad Sci U S A 2020; 117:29046-29054. [PMID: 33139575 PMCID: PMC7682387 DOI: 10.1073/pnas.2010199117] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The cell morphology of rod-shaped bacteria is determined by the rigid net of peptidoglycan forming the cell wall. Alterations to the rod shape, such as the curved rod, occur through manipulating the process of cell wall synthesis. The human pathogen Vibrio cholerae typically exists as a curved rod, but straight rods have been observed under certain conditions. While this appears to be a regulated process, the regulatory pathways controlling cell shape transitions in V. cholerae and the benefits of switching between rod and curved shape have not been determined. We demonstrate that cell shape in V. cholerae is regulated by the bacterial second messenger cyclic dimeric guanosine monophosphate (c-di-GMP) by posttranscriptionally repressing expression of crvA, a gene encoding an intermediate filament-like protein necessary for curvature formation in V. cholerae. This regulation is mediated by the transcriptional cascade that also induces production of biofilm matrix components, indicating that cell shape is coregulated with V. cholerae's induction of sessility. During microcolony formation, wild-type V. cholerae cells tended to exist as straight rods, while genetically engineering cells to maintain high curvature reduced microcolony formation and biofilm density. Conversely, straight V. cholerae mutants have reduced swimming speed when using flagellar motility in liquid. Our results demonstrate regulation of cell shape in bacteria is a mechanism to increase fitness in planktonic and biofilm lifestyles.
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Affiliation(s)
- Nicolas L Fernandez
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824
| | - Brian Y Hsueh
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824
| | - Nguyen T Q Nhu
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824
| | - Joshua L Franklin
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824
| | - Yann S Dufour
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824
| | - Christopher M Waters
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824
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32
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Li J, Zhao X. Effects of quorum sensing on the biofilm formation and viable but non-culturable state. Food Res Int 2020; 137:109742. [DOI: 10.1016/j.foodres.2020.109742] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 09/08/2020] [Accepted: 09/18/2020] [Indexed: 02/07/2023]
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33
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Hoyos M, Huber M, Förstner KU, Papenfort K. Gene autoregulation by 3' UTR-derived bacterial small RNAs. eLife 2020; 9:58836. [PMID: 32744240 PMCID: PMC7398697 DOI: 10.7554/elife.58836] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/23/2020] [Indexed: 01/01/2023] Open
Abstract
Negative feedback regulation, that is the ability of a gene to repress its own synthesis, is the most abundant regulatory motif known to biology. Frequently reported for transcriptional regulators, negative feedback control relies on binding of a transcription factor to its own promoter. Here, we report a novel mechanism for gene autoregulation in bacteria relying on small regulatory RNA (sRNA) and the major endoribonuclease, RNase E. TIER-seq analysis (transiently-inactivating-an-endoribonuclease-followed-by-RNA-seq) revealed ~25,000 RNase E-dependent cleavage sites in Vibrio cholerae, several of which resulted in the accumulation of stable sRNAs. Focusing on two examples, OppZ and CarZ, we discovered that these sRNAs are processed from the 3' untranslated region (3' UTR) of the oppABCDF and carAB operons, respectively, and base-pair with their own transcripts to inhibit translation. For OppZ, this process also triggers Rho-dependent transcription termination. Our data show that sRNAs from 3' UTRs serve as autoregulatory elements allowing negative feedback control at the post-transcriptional level.
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Affiliation(s)
- Mona Hoyos
- Friedrich Schiller University Jena, Institute of Microbiology, Jena, Germany.,Faculty of Biology I, Ludwig-Maximilians-University of Munich, Martinsried, Germany
| | - Michaela Huber
- Friedrich Schiller University Jena, Institute of Microbiology, Jena, Germany.,Faculty of Biology I, Ludwig-Maximilians-University of Munich, Martinsried, Germany
| | - Konrad U Förstner
- TH Köln - University of Applied Sciences, Institute of Information Science, Cologne, Germany.,ZB MED - Information Centre for Life Sciences, Cologne, Germany
| | - Kai Papenfort
- Friedrich Schiller University Jena, Institute of Microbiology, Jena, Germany.,Faculty of Biology I, Ludwig-Maximilians-University of Munich, Martinsried, Germany.,Microverse Cluster, Friedrich Schiller University Jena, Jena, Germany
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34
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Erwinia carotovora Quorum Sensing System Regulates Host-Specific Virulence Factors and Development Delay in Drosophila melanogaster. mBio 2020; 11:mBio.01292-20. [PMID: 32576677 PMCID: PMC7315124 DOI: 10.1128/mbio.01292-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Integration of genetic networks allows bacteria to rapidly adapt to changing environments. This is particularly important in bacteria that interact with multiple hosts. Erwinia carotovora is a plant pathogen that uses Drosophila melanogaster as a vector. To interact with these two hosts, Ecc15 uses different sets of virulence factors: plant cell wall-degrading enzymes to infect plants and the Erwinia virulence factor (evf) to infect Drosophila. Our work shows that, despite the virulence factors being specific for each host, both sets are coactivated by homoserine lactone quorum sensing and by the two-component GacS/A system in infected plants. This regulation is essential for Ecc15 loads in the gut of Drosophila and minimizes the developmental delay caused by the bacteria with respect to the insect vector. Our findings provide evidence that coactivation of the host-specific factors in the plant may function as a predictive mechanism to maximize the probability of transit of the bacteria between hosts. Multihost bacteria have to rapidly adapt to drastic environmental changes, relying on a fine integration of multiple stimuli for an optimal genetic response. Erwinia carotovora spp. are phytopathogens that cause soft-rot disease. Strain Ecc15 in particular is a model for bacterial oral-route infection in Drosophila melanogaster as it harbors a unique gene, evf, that encodes the Erwinia virulence factor (Evf), which is a major determinant for infection of the D. melanogaster gut. However, the factors involved in the regulation of evf expression are poorly understood. We investigated whether evf could be controlled by quorum sensing as, in the Erwinia genus, quorum sensing regulates pectolytic enzymes, the major virulence factors needed to infect plants. Here, we show that transcription of evf is positively regulated by quorum sensing in Ecc15 via acyl-homoserine lactone (AHL) signal synthase ExpI and AHL receptors ExpR1 and ExpR2. We also show that the load of Ecc15 in the gut depends upon the quorum sensing-mediated regulation of evf. Furthermore, we demonstrate that larvae infected with Ecc15 suffer a developmental delay as a direct consequence of the regulation of evf via quorum sensing. Finally, we demonstrate that evf is coexpressed with plant cell wall-degrading enzymes (PCWDE) during plant infection in a quorum sensing-dependent manner. Overall, our results show that Ecc15 relies on quorum sensing to control production of both pectolytic enzymes and Evf. This regulation influences the interaction of Ecc15 with its two known hosts, indicating that quorum sensing signaling may impact bacterial dissemination via insect vectors that feed on rotting plants.
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35
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Vishwakarma J, V.L S. Unraveling the anti-biofilm potential of green algal sulfated polysaccharides against Salmonella enterica and Vibrio harveyi. Appl Microbiol Biotechnol 2020; 104:6299-6314. [DOI: 10.1007/s00253-020-10653-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 04/08/2020] [Accepted: 04/29/2020] [Indexed: 01/06/2023]
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Aqawi M, Gallily R, Sionov RV, Zaks B, Friedman M, Steinberg D. Cannabigerol Prevents Quorum Sensing and Biofilm Formation of Vibrio harveyi. Front Microbiol 2020; 11:858. [PMID: 32457724 PMCID: PMC7221000 DOI: 10.3389/fmicb.2020.00858] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/09/2020] [Indexed: 11/30/2022] Open
Abstract
Cannabigerol (CBG) is a non-psychoactive cannabinoid naturally present in trace amounts in the Cannabis plant. So far, CBG has been shown to exert diverse activities in eukaryotes. However, much less is known about its effects on prokaryotes. In this study, we investigated the potential role of CBG as an anti-biofilm and anti-quorum sensing agent against Vibrio harveyi. Quorum sensing (QS) is a cell-to-cell communication system among bacteria that involves small signaling molecules called autoinducers, enabling bacteria to sense the surrounding environment. The autoinducers cause alterations in gene expression and induce bioluminescence, pigment production, motility and biofilm formation. The effect of CBG was tested on V. harveyi grown under planktonic and biofilm conditions. CBG reduced the QS-regulated bioluminescence and biofilm formation of V. harveyi at concentrations not affecting the planktonic bacterial growth. CBG also reduced the motility of V. harveyi in a dose-dependent manner. We further observed that CBG increased LuxO expression and activity, with a concomitant 80% downregulation of the LuxR gene. Exogenous addition of autoinducers could not overcome the QS-inhibitory effect of CBG, suggesting that CBG interferes with the transmission of the autoinducer signals. In conclusion, our study shows that CBG is a potential anti-biofilm agent via inhibition of the QS cascade.
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Affiliation(s)
- Muna Aqawi
- The Biofilm Research Laboratory, The Faculty of Dental Medicine, The Institute of Dental Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ruth Gallily
- The Lautenberg Center for General and Tumor Immunology, The Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ronit Vogt Sionov
- The Biofilm Research Laboratory, The Faculty of Dental Medicine, The Institute of Dental Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Batya Zaks
- The Biofilm Research Laboratory, The Faculty of Dental Medicine, The Institute of Dental Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Michael Friedman
- The Department of Pharmaceutics, The Faculty of Medicine, The Institute of Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Doron Steinberg
- The Biofilm Research Laboratory, The Faculty of Dental Medicine, The Institute of Dental Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
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Copley SD. The physical basis and practical consequences of biological promiscuity. Phys Biol 2020; 17:10.1088/1478-3975/ab8697. [PMID: 32244231 PMCID: PMC9291633 DOI: 10.1088/1478-3975/ab8697] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Proteins interact with metabolites, nucleic acids, and other proteins to orchestrate the myriad catalytic, structural and regulatory functions that support life from the simplest microbes to the most complex multicellular organisms. These molecular interactions are often exquisitely specific, but never perfectly so. Adventitious "promiscuous" interactions are ubiquitous due to the thousands of macromolecules and small molecules crowded together in cells. Such interactions may perturb protein function at the molecular level, but as long as they do not compromise organismal fitness, they will not be removed by natural selection. Although promiscuous interactions are physiologically irrelevant, they are important because they can provide a vast reservoir of potential functions that can provide the starting point for evolution of new functions, both in nature and in the laboratory.
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Affiliation(s)
- Shelley D Copley
- Department of Molecular, Cellular and Developmental Biology and Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, UNITED STATES
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Parallel quorum-sensing system in Vibrio cholerae prevents signal interference inside the host. PLoS Pathog 2020; 16:e1008313. [PMID: 32059031 PMCID: PMC7046293 DOI: 10.1371/journal.ppat.1008313] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 02/27/2020] [Accepted: 01/08/2020] [Indexed: 12/26/2022] Open
Abstract
Many bacteria use quorum sensing (QS) to regulate virulence factor production in response to changes in population density. QS is mediated through the production, secretion, and detection of signaling molecules called autoinducers (AIs) to modulate population-wide behavioral changes. Four histidine kinases, LuxPQ, CqsS, CqsR and VpsS, have been identified in Vibrio cholerae as QS receptors to activate virulence gene expression at low cell density. Detection of AIs by these receptors leads to virulence gene repression at high cell density. The redundancy among these receptors is puzzling since any one of the four receptors is sufficient to support colonization of V. cholerae in the host small intestine. It is believed that one of the functions of such circuit architecture is to prevent interference on any single QS receptor. However, it is unclear what natural molecules can interfere V. cholerae QS and in what environment interference is detrimental. We show here mutants expressing only CqsR without the other three QS receptors are defective in colonizing the host large intestine. We identified ethanolamine, a common intestinal metabolite that can function as a chemical source of QS interference. Ethanolamine specifically interacts with the ligand-binding CACHE domain of CqsR and induces a premature QS response in V. cholerae mutants expressing only CqsR without the other three QS receptors. The effect of ethanolamine on QS gene expression and host colonization is abolished by mutations that disrupt CqsR signal sensing. V. cholerae defective in producing ethanolamine is still proficient in QS, therefore, ethanolamine functions only as an external cue for CqsR. Our findings suggest the inhibitory effect of ethanolamine on CqsR could be a possible source of QS interference but is masked by the presence of the other parallel QS pathways, allowing V. cholerae to robustly colonize the host. Many pathogens use quorum sensing (QS) to regulate virulence gene expression for their survival and adaptation inside hosts. QS depends on the production and detection of chemical signals called autoinducers made endogenously by the bacteria. However, chemicals present in the surrounding environment could potentially lead to quorum signal interference, resulting in mis-regulation of virulence factor production and preventing effective host colonization. We show here ethanolamine, a metabolite commonly found inside the mammalian intestine, modulates the activity of one of the QS receptors in Vibrio cholerae, the etiological agent of the disease cholera. Despite the abundance of this common metabolite inside the host, by integrating multiple parallel signal inputs into its QS system, V. cholerae has evolved to maintain QS fidelity and avoids signal interference to allow robust colonization of the host.
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Orazi G, O'Toole GA. "It Takes a Village": Mechanisms Underlying Antimicrobial Recalcitrance of Polymicrobial Biofilms. J Bacteriol 2019; 202:e00530-19. [PMID: 31548277 PMCID: PMC6932244 DOI: 10.1128/jb.00530-19] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Chronic infections are frequently caused by polymicrobial biofilms. Importantly, these infections are often difficult to treat effectively in part due to the recalcitrance of biofilms to antimicrobial therapy. Emerging evidence suggests that polymicrobial interactions can lead to dramatic and unexpected changes in the ability of antibiotics to eradicate biofilms and often result in decreased antimicrobial efficacy in vitro In this review, we discuss the influence of polymicrobial interactions on the antibiotic susceptibility of biofilms, and we highlight the studies that first documented the shifted antimicrobial susceptibilities of mixed-species cultures. Recent studies have identified several mechanisms underlying the recalcitrance of polymicrobial biofilm communities, including interspecies exchange of antibiotic resistance genes, β-lactamase-mediated inactivation of antibiotics, changes in gene expression induced by metabolites and quorum sensing signals, inhibition of the electron transport chain, and changes in properties of the cell membrane. In addition to elucidating multiple mechanisms that contribute to the altered drug susceptibility of polymicrobial biofilms, these studies have uncovered novel ways in which polymicrobial interactions can impact microbial physiology. The diversity of findings discussed highlights the importance of continuing to investigate the efficacy of antibiotics against biofilm communities composed of different combinations of microbial species. Together, the data presented here illustrate the importance of studying microbes as part of mixed-species communities rather than in isolation. In light of our greater understanding of how interspecies interactions alter the efficacy of antimicrobial agents, we propose that the methods for measuring the drug susceptibility of polymicrobial infections should be revisited.
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Affiliation(s)
- Giulia Orazi
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - George A O'Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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Quorum Sensing Regulators AphA and OpaR Control Expression of the Operon Responsible for Biosynthesis of the Compatible Solute Ectoine. Appl Environ Microbiol 2019; 85:AEM.01543-19. [PMID: 31519665 DOI: 10.1128/aem.01543-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 09/09/2019] [Indexed: 12/14/2022] Open
Abstract
To maintain the turgor pressure of the cell under high osmolarity, bacteria accumulate small organic compounds called compatible solutes, either through uptake or biosynthesis. Vibrio parahaemolyticus, a marine halophile and an important human and shellfish pathogen, has to adapt to abiotic stresses such as changing salinity. Vibrio parahaemolyticus contains multiple compatible solute biosynthesis and transporter systems, including the ectABC-asp_ect operon required for de novo ectoine biosynthesis. Ectoine biosynthesis genes are present in many halotolerant bacteria; however, little is known about the mechanism of regulation. We investigated the role of the quorum sensing master regulators OpaR and AphA in ect gene regulation. In an opaR deletion mutant, transcriptional reporter assays demonstrated that ect expression was induced. In an electrophoretic mobility shift assay, we showed that purified OpaR bound to the ect regulatory region indicating direct regulation by OpaR. In an aphA deletion mutant, expression of the ect genes was repressed, and purified AphA bound upstream of the ect genes. These data indicate that AphA is a direct positive regulator. CosR, a Mar-type regulator known to repress ect expression in V. cholerae, was found to repress ect expression in V. parahaemolyticus In addition, we identified a feed-forward loop in which OpaR is a direct activator of cosR, while AphA is an indirect activator of cosR Regulation of the ectoine biosynthesis pathway via this feed-forward loop allows for precise control of ectoine biosynthesis genes throughout the growth cycle to maximize fitness.IMPORTANCE Accumulation of compatible solutes within the cell allows bacteria to maintain intracellular turgor pressure and prevent water efflux. De novo ectoine production is widespread among bacteria, and the ect operon encoding the biosynthetic enzymes is induced by increased salinity. Here, we demonstrate that the quorum sensing regulators AphA and OpaR integrate with the osmotic stress response pathway to control transcription of ectoine biosynthesis genes in V. parahaemolyticus We uncovered a feed-forward loop wherein quorum sensing regulators also control transcription of cosR, which encodes a negative regulator of the ect operon. Moreover, our data suggest that this mechanism may be widespread in Vibrio species.
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Heckler I, Boon EM. Insights Into Nitric Oxide Modulated Quorum Sensing Pathways. Front Microbiol 2019; 10:2174. [PMID: 31608029 PMCID: PMC6769237 DOI: 10.3389/fmicb.2019.02174] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 09/05/2019] [Indexed: 11/13/2022] Open
Abstract
The emerging threat of drug resistant bacteria has prompted the investigation into bacterial signaling pathways responsible for pathogenesis. One such mechanism by which bacteria regulate their physiology during infection of a host is through a process known as quorum sensing (QS). Bacteria use QS to regulate community-wide gene expression in response to changes in population density. In order to sense these changes in population density, bacteria produce, secrete and detect small molecules called autoinducers. The most common signals detected by Gram-negative and Gram-positive bacteria are acylated homoserine lactones and autoinducing peptides (AIPs), respectively. However, increasing evidence has supported a role for the small molecule nitric oxide (NO) in influencing QS-mediated group behaviors like bioluminescence, biofilm production, and virulence. In this review, we discuss three bacteria that have an established role for NO in influencing bacterial physiology through QS circuits. In two Vibrio species, NO has been shown to affect QS pathways upon coordination of hemoprotein sensors. Further, NO has been demonstrated to serve a protective role against staphylococcal pneumonia through S-nitrosylation of a QS regulator of virulence.
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Girard L. Quorum sensing in Vibrio spp.: the complexity of multiple signalling molecules in marine and aquatic environments. Crit Rev Microbiol 2019; 45:451-471. [PMID: 31241379 DOI: 10.1080/1040841x.2019.1624499] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Quorum sensing (QS) is a density-dependent mechanism enabling bacteria to coordinate their actions via the release of small diffusible molecules named autoinducers (AIs). Vibrio spp. are able to adapt to changing environmental conditions by using a wide range of physiological mechanisms and many species pose a threat for human health and diverse marine and estuarine ecosystems worldwide. Cell-to-cell communication controls many of their vital functions such as niche colonization, survival strategies, or virulence. In this review, I summarize (1) the different known QS pathways (2) the diversity of AIs as well as their biological functions, and (3) the QS-mediated interactions between Vibrio and other organisms. However, the current knowledge is limited to a few pathogenic or bioluminescent species and in order to provide a genus-wide view an inventory of QS genes among 87 Vibrio species has been made. The large diversity of signal molecules and their differential effects on a particular physiological function suggest that the complexity of multiple signalling systems within bacterial communities is far from being fully understood. I question here the real level of specificity of such communication in the environment and discuss the different perspectives in order to better apprehend QS in natural habitats.
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Affiliation(s)
- Léa Girard
- Centre of Microbial and Plant Genetics , KU Leuven , Belgium
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43
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Friedman L, Smoum R, Feldman M, Mechoulam R, Steinberg D. Does the Endocannabinoid Anandamide Affect Bacterial Quorum Sensing, Vitality, and Motility? Cannabis Cannabinoid Res 2019. [DOI: 10.1089/can.2018.0055] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Liat Friedman
- Biofilm Research Laboratory, Bio-medicine Graduate Program, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Reem Smoum
- The Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Mark Feldman
- Biofilm Research Laboratory, Bio-medicine Graduate Program, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Raphael Mechoulam
- The Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Doron Steinberg
- Biofilm Research Laboratory, Bio-medicine Graduate Program, The Hebrew University of Jerusalem, Jerusalem, Israel
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44
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Francis VI, Porter SL. Multikinase Networks: Two-Component Signaling Networks Integrating Multiple Stimuli. Annu Rev Microbiol 2019; 73:199-223. [PMID: 31112439 DOI: 10.1146/annurev-micro-020518-115846] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Bacteria depend on two-component systems to detect and respond to threats. Simple pathways comprise a single sensor kinase (SK) that detects a signal and activates a response regulator protein to mediate an appropriate output. These simple pathways with only a single SK are not well suited to making complex decisions where multiple different stimuli need to be evaluated. A recently emerging theme is the existence of multikinase networks (MKNs) where multiple SKs collaborate to detect and integrate numerous different signals to regulate a major lifestyle switch, e.g., between virulence, sporulation, biofilm formation, and cell division. In this review, the role of MKNs and the phosphosignaling mechanisms underpinning their signal integration and decision making are explored.
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Affiliation(s)
- Vanessa I Francis
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, United Kingdom; ,
| | - Steven L Porter
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, United Kingdom; ,
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45
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Spangler JR, Dean SN, Leary DH, Walper SA. Response of Lactobacillus plantarum WCFS1 to the Gram-Negative Pathogen-Associated Quorum Sensing Molecule N-3-Oxododecanoyl Homoserine Lactone. Front Microbiol 2019; 10:715. [PMID: 31024494 PMCID: PMC6459948 DOI: 10.3389/fmicb.2019.00715] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 03/21/2019] [Indexed: 12/18/2022] Open
Abstract
The bacterial quorum sensing phenomenon has been well studied since its discovery and has traditionally been considered to include signaling pathways recognized exclusively within either Gram-positive or Gram-negative bacteria. These groups of bacteria synthesize structurally distinct signaling molecules to mediate quorum sensing, where Gram-positive bacteria traditionally utilize small autoinducing peptides (AIPs) and Gram-negatives use small molecules such as acyl-homoserine lactones (AHLs). The structural differences between the types of signaling molecules have historically implied a lack of cross-talk among Gram-positive and Gram-negative quorum sensing systems. Recent investigations, however, have demonstrated the ability for AIPs and AHLs to be produced by non-canonical organisms, implying quorum sensing systems may be more universally recognized than previously hypothesized. With that in mind, our interests were piqued by the organisms Lactobacillus plantarum, a Gram-positive commensal probiotic known to participate in AIP-mediated quorum sensing, and Pseudomonas aeruginosa, a characterized Gram-negative pathogen whose virulence is in part controlled by AHL-mediated quorum sensing. Both health-related organisms are known to inhabit the human gut in various instances, both are characterized to elicit distinct effects on host immunity, and some studies hint at the putative ability of L. plantarum to degrade AHLs produced by P. aeruginosa. We therefore wanted to determine if L. plantarum cultures would respond to the addition of N-(3-oxododecanoyl)-L-homoserine lactone (3OC12) from P. aeruginosa by analyzing changes on both the transcriptome and proteome over time. Based on the observed upregulation of various two-component systems, response regulators, and native quorum sensing related genes, the resulting data provide evidence of an AHL recognition and response by L. plantarum.
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Affiliation(s)
- Joseph R. Spangler
- National Research Council Postdoctoral Fellowships, NRC Research Associateship Programs, Washington, DC, United States
| | - Scott N. Dean
- National Research Council Postdoctoral Fellowships, NRC Research Associateship Programs, Washington, DC, United States
| | - Dagmar H. Leary
- United States Naval Research Laboratory, Center for Biomolecular Science and Engineering, Washington, DC, United States
| | - Scott A. Walper
- United States Naval Research Laboratory, Center for Biomolecular Science and Engineering, Washington, DC, United States
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46
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Ball AS, van Kessel JC. The master quorum-sensing regulators LuxR/HapR directly interact with the alpha subunit of RNA polymerase to drive transcription activation in Vibrio harveyi and Vibrio cholerae. Mol Microbiol 2019; 111:1317-1334. [PMID: 30742725 DOI: 10.1111/mmi.14223] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2019] [Indexed: 12/19/2022]
Abstract
In Vibrio species, quorum sensing controls gene expression for numerous group behaviors, including bioluminescence production, biofilm formation, virulence factor secretion systems, and competence. The LuxR/HapR master quorum-sensing regulators activate expression of hundreds of genes in response to changes in population densities. The mechanism of transcription activation by these TetR-type transcription factors is unknown, though LuxR DNA binding sites that lie in close proximity to the -35 region of the promoter are required for activation at some promoters. Here, we show that Vibrio harveyi LuxR directly interacts with RNA polymerase to activate transcription of the luxCDABE bioluminescence genes. LuxR interacts with RNA polymerase in vitro and in vivo and specifically interacts with both the N- and C-terminal domains of the RNA polymerase α-subunit. Amino acid substitutions in the RNAP interaction domain on LuxR decrease interactions between LuxR and the α-subunit and result in defects in transcription activation of quorum-sensing genes in vivo. The RNAP-LuxR interaction domain is conserved in Vibrio cholerae HapR and is required for activation of the HapR-regulated gene hapA. Our findings support a model in which LuxR/HapR bind proximally to RNA polymerase to drive transcription initiation at a subset of quorum-sensing genes in Vibrio species.
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Affiliation(s)
- Alyssa S Ball
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
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47
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Martín-Rodríguez AJ, Álvarez-Méndez SJ, Overå C, Baruah K, Lourenço TM, Norouzitallab P, Bossier P, Martín VS, Fernández JJ. The 9 H-Fluoren Vinyl Ether Derivative SAM461 Inhibits Bacterial Luciferase Activity and Protects Artemia franciscana From Luminescent Vibriosis. Front Cell Infect Microbiol 2018; 8:368. [PMID: 30467537 PMCID: PMC6236115 DOI: 10.3389/fcimb.2018.00368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 10/03/2018] [Indexed: 11/13/2022] Open
Abstract
Vibrio campbellii is a major pathogen in aquaculture. It is a causative agent of the so-called “luminescent vibriosis,” a life-threatening condition caused by bioluminescent Vibrio spp. that often involves mass mortality of farmed shrimps. The emergence of multidrug resistant Vibrio strains raises a concern and poses a challenge for the treatment of this infection in the coming years. Inhibition of bacterial cell-to-cell communication or quorum sensing (QS) has been proposed as an alternative to antibiotic therapies. Aiming to identify novel QS disruptors, the 9H-fluroen-9yl vinyl ether derivative SAM461 was found to thwart V. campbellii bioluminescence, a QS-regulated phenotype. Phenotypic and gene expression analyses revealed, however, that the mode of action of SAM461 was unrelated to QS inhibition. Further evaluation with purified Vibrio fischeri and NanoLuc luciferases revealed enzymatic inhibition at micromolar concentrations. In silico analysis by molecular docking suggested binding of SAM461 in the active site cavities of both luciferase enzymes. Subsequent in vivo testing of SAM461 with gnotobiotic Artemia franciscana nauplii demonstrated naupliar protection against V. campbellii infection at low micromolar concentrations. Taken together, these findings suggest that suppression of luciferase activity could constitute a novel paradigm in the development of alternative anti-infective chemotherapies against luminescent vibriosis, and pave the ground for the chemical synthesis and biological characterization of derivatives with promising antimicrobial prospects.
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Affiliation(s)
- Alberto J Martín-Rodríguez
- Instituto Universitario de Bio-Orgánica "Antonio González", Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, Tenerife, Spain.,Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Sergio J Álvarez-Méndez
- Instituto Universitario de Bio-Orgánica "Antonio González", Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, Tenerife, Spain
| | - Caroline Overå
- Institute of Biophysics and Biophysical Chemistry, University of Regensburg, Regensburg, Germany
| | - Kartik Baruah
- Laboratory of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.,Department of Animal Nutrition and Management, Faculty of Veterinary Medicine and Animal Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Tânia Margarida Lourenço
- Laboratory of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Parisa Norouzitallab
- Laboratory of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.,Laboratory of Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Ghent University, Ghent, Belgium
| | - Peter Bossier
- Laboratory of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Víctor S Martín
- Instituto Universitario de Bio-Orgánica "Antonio González", Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, Tenerife, Spain
| | - José J Fernández
- Instituto Universitario de Bio-Orgánica "Antonio González", Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, Tenerife, Spain
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The PedS2/PedR2 Two-Component System Is Crucial for the Rare Earth Element Switch in Pseudomonas putida KT2440. mSphere 2018; 3:3/4/e00376-18. [PMID: 30158283 PMCID: PMC6115532 DOI: 10.1128/msphere.00376-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The function of lanthanides for methanotrophic and methylotrophic bacteria is gaining increasing attention, while knowledge about the role of rare earth elements (REEs) in nonmethylotrophic bacteria is still limited. The present study investigates the recently described differential expression of the two PQQ-EDHs of P. putida in response to lanthanides. We demonstrate that a specific TCS is crucial for their inverse regulation and provide evidence for a dual regulatory function of the LuxR-type response regulator involved. Thus, our study represents the first detailed characterization of the molecular mechanism underlying the REE switch of PQQ-EDHs in a nonmethylotrophic bacterium and stimulates subsequent investigations for the identification of additional genes or phenotypic traits that might be coregulated during REE-dependent niche adaptation. In Pseudomonas putida KT2440, two pyrroloquinoline quinone-dependent ethanol dehydrogenases (PQQ-EDHs) are responsible for the periplasmic oxidation of a broad variety of volatile organic compounds (VOCs). Depending on the availability of rare earth elements (REEs) of the lanthanide series (Ln3+), we have recently reported that the transcription of the genes encoding the Ca2+-utilizing enzyme PedE and the Ln3+-utilizing enzyme PedH are inversely regulated. With adaptive evolution experiments, site-specific mutations, transcriptional reporter fusions, and complementation approaches, we now demonstrate that the PedS2/PedR2 (PP_2671/PP_2672) two-component system (TCS) plays a central role in the observed REE-mediated switch of PQQ-EDHs in P. putida. We provide evidence that in the absence of lanthanum (La3+), the sensor histidine kinase PedS2 phosphorylates its cognate LuxR-type response regulator PedR2, which in turn not only activates pedE gene transcription but is also involved in repression of pedH. Our data further suggest that the presence of La3+ lowers kinase activity of PedS2, either by the direct binding of the metal ions to the periplasmic region of PedS2 or by an uncharacterized indirect interaction, leading to reduced levels of phosphorylated PedR2. Consequently, the decreasing pedE expression and concomitant alleviation of pedH repression causes—in conjunction with the transcriptional activation of the pedH gene by a yet unknown regulatory module—the Ln3+-dependent transition from PedE- to PedH-catalyzed oxidation of alcoholic VOCs. IMPORTANCE The function of lanthanides for methanotrophic and methylotrophic bacteria is gaining increasing attention, while knowledge about the role of rare earth elements (REEs) in nonmethylotrophic bacteria is still limited. The present study investigates the recently described differential expression of the two PQQ-EDHs of P. putida in response to lanthanides. We demonstrate that a specific TCS is crucial for their inverse regulation and provide evidence for a dual regulatory function of the LuxR-type response regulator involved. Thus, our study represents the first detailed characterization of the molecular mechanism underlying the REE switch of PQQ-EDHs in a nonmethylotrophic bacterium and stimulates subsequent investigations for the identification of additional genes or phenotypic traits that might be coregulated during REE-dependent niche adaptation.
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Mechanisms of Bacterial Tolerance and Persistence in the Gastrointestinal and Respiratory Environments. Clin Microbiol Rev 2018; 31:31/4/e00023-18. [PMID: 30068737 DOI: 10.1128/cmr.00023-18] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Pathogens that infect the gastrointestinal and respiratory tracts are subjected to intense pressure due to the environmental conditions of the surroundings. This pressure has led to the development of mechanisms of bacterial tolerance or persistence which enable microorganisms to survive in these locations. In this review, we analyze the general stress response (RpoS mediated), reactive oxygen species (ROS) tolerance, energy metabolism, drug efflux pumps, SOS response, quorum sensing (QS) bacterial communication, (p)ppGpp signaling, and toxin-antitoxin (TA) systems of pathogens, such as Escherichia coli, Salmonella spp., Vibrio spp., Helicobacter spp., Campylobacter jejuni, Enterococcus spp., Shigella spp., Yersinia spp., and Clostridium difficile, all of which inhabit the gastrointestinal tract. The following respiratory tract pathogens are also considered: Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Burkholderia cenocepacia, and Mycobacterium tuberculosis Knowledge of the molecular mechanisms regulating the bacterial tolerance and persistence phenotypes is essential in the fight against multiresistant pathogens, as it will enable the identification of new targets for developing innovative anti-infective treatments.
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Outer Membrane Vesicles Facilitate Trafficking of the Hydrophobic Signaling Molecule CAI-1 between Vibrio harveyi Cells. J Bacteriol 2018; 200:JB.00740-17. [PMID: 29555694 DOI: 10.1128/jb.00740-17] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/06/2018] [Indexed: 11/20/2022] Open
Abstract
Many bacteria use extracellular signaling molecules to coordinate group behavior, a process referred to as quorum sensing (QS). However, some QS molecules are hydrophobic in character and are probably unable to diffuse across the bacterial cell envelope. How these molecules are disseminated between bacterial cells within a population is not yet fully understood. Here, we show that the marine pathogen Vibrio harveyi packages the hydrophobic QS molecule CAI-1, a long-chain amino ketone, into outer membrane vesicles. Electron micrographs indicate that outer membrane vesicles of variable size are predominantly produced and released into the surroundings during the stationary phase of V. harveyi, which correlates with the timing of CAI-1-dependent signaling. The large vesicles (diameter, <55 nm) can trigger a QS phenotype in CAI-1-nonproducing V. harveyi and Vibrio cholerae cells. Packaging of CAI-1 into outer membrane vesicles might stabilize the molecule in aqueous environments and facilitate its distribution over distances.IMPORTANCE Formation of membrane vesicles is ubiquitous among bacteria. These vesicles are involved in protein and DNA transfer and offer new approaches for vaccination. Gram-negative bacteria use hydrophobic signaling molecules, among others, for cell-cell communication; however, due to their hydrophobic character, it is unclear how these molecules are disseminated between bacterial cells. Here, we show that the marine pathogen Vibrio harveyi packages one of its QS molecules, the long-chain ketone CAI-1, into outer membrane vesicles (OMVs). Isolated CAI-1-containing vesicles trigger a QS phenotype in CAI-1 nonproducing V. harveyi and also in Vibrio cholerae cells. Packaging of CAI-1 into OMVs not only solubilizes, stabilizes, and concentrates this class of molecules, but facilitate their distribution between bacteria that live in aqueous environments.
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