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Burke Ó, Zeden MS, O'Gara JP. The pathogenicity and virulence of the opportunistic pathogen Staphylococcus epidermidis. Virulence 2024; 15:2359483. [PMID: 38868991 DOI: 10.1080/21505594.2024.2359483] [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: 02/02/2024] [Accepted: 05/19/2024] [Indexed: 06/14/2024] Open
Abstract
The pervasive presence of Staphylococcus epidermidis and other coagulase-negative staphylococci on the skin and mucous membranes has long underpinned a casual disregard for the infection risk that these organisms pose to vulnerable patients in healthcare settings. Prior to the recognition of biofilm as an important virulence determinant in S. epidermidis, isolation of this microorganism in diagnostic specimens was often overlooked as clinically insignificant with potential delays in diagnosis and onset of appropriate treatment, contributing to the establishment of chronic infection and increased morbidity or mortality. While impressive progress has been made in our understanding of biofilm mechanisms in this important opportunistic pathogen, research into other virulence determinants has lagged S. aureus. In this review, the broader virulence potential of S. epidermidis including biofilm, toxins, proteases, immune evasion strategies and antibiotic resistance mechanisms is surveyed, together with current and future approaches for improved therapeutic interventions.
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Affiliation(s)
- Órla Burke
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | | | - James P O'Gara
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
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2
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Moreno-Gámez S, Hochberg ME, van Doorn GS. Quorum sensing as a mechanism to harness the wisdom of the crowds. Nat Commun 2023; 14:3415. [PMID: 37296108 PMCID: PMC10256802 DOI: 10.1038/s41467-023-37950-7] [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: 03/16/2022] [Accepted: 04/05/2023] [Indexed: 06/12/2023] Open
Abstract
Bacteria release and sense small molecules called autoinducers in a process known as quorum sensing. The prevailing interpretation of quorum sensing is that by sensing autoinducer concentrations, bacteria estimate population density to regulate the expression of functions that are only beneficial when carried out by a sufficiently large number of cells. However, a major challenge to this interpretation is that the concentration of autoinducers strongly depends on the environment, often rendering autoinducer-based estimates of cell density unreliable. Here we propose an alternative interpretation of quorum sensing, where bacteria, by releasing and sensing autoinducers, harness social interactions to sense the environment as a collective. Using a computational model we show that this functionality can explain the evolution of quorum sensing and arises from individuals improving their estimation accuracy by pooling many imperfect estimates - analogous to the 'wisdom of the crowds' in decision theory. Importantly, our model reconciles the observed dependence of quorum sensing on both population density and the environment and explains why several quorum sensing systems regulate the production of private goods.
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Affiliation(s)
- Stefany Moreno-Gámez
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, P.O. Box 11103, 9700 CC, Groningen, The Netherlands.
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Michael E Hochberg
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, 34095, Montpellier, France
- Santa Fe Institute, Santa Fe, NM, 87501, USA
| | - G S van Doorn
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, P.O. Box 11103, 9700 CC, Groningen, The Netherlands
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3
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Chopra A, Mongad D, Satpute S, Mazumder PB, Rahi P. Quorum sensing activities and genomic insights of plant growth-promoting rhizobacteria isolated from Assam tea. World J Microbiol Biotechnol 2023; 39:160. [PMID: 37067647 DOI: 10.1007/s11274-023-03608-1] [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: 11/09/2022] [Accepted: 04/05/2023] [Indexed: 04/18/2023]
Abstract
Secretion of quorum sensing (QS) molecules is important for the effective colonization of host plants by plant growth-promoting rhizobacteria. The current study aims at the isolation and characterization of tea rhizo bacteria, which produce the QS molecules, acyl homoserine lactone (AHLs), along with multiple plant growth-promoting (PGP) activities. Thirty-one isolates were isolated from the tea rhizosphere, and screening for PGP activities resulted in the selection of isolates RTE1 and RTE4 with multiple PGP traits, inhibiting the growth of tea fungal pathogens. Both isolates also showed production of AHL molecules when screened using two biosensor strains, Chromobacterium violaceum CV026 and Escherichia coli MT 102(jb132). The isolates identified as Burkholderia cepacia RTE1 and Pseudomonas aeruginosa RTE4 based on genome-based analysis like phylogeny, dDDH, and fastANI calculation. Detailed characterization of AHLs produced by the isolates using reverse-phase TLC, fluorometry, and LC-MS indicated that the isolate RTE1 produced a short chain, C8, and a long chain C12 AHL, while RTE4 produced short-chain AHLs C4 and C6. Confocal microscopy revealed the formation of thick biofilm by RTE1 and RTE4 (18 and 23 μm, respectively). Additionally, we found several genes involved in QS, and PGP, inducing systemic resistance (ISR) activities such as lasI/R, qscR, pqq, pvd, aldH, acdS, phz, Sod, rml, and Pch, and biosynthetic gene clusters like N-acyl homoserine lactone synthase, terpenes, pyochelin, and pyocyanin. Based on the functional traits like PGP, biofilm formation and production of AHL molecules, and genetic potential of the isolates B. cepacia RTE1 and P. aeruginosa RTE4 appear promising candidates to improve the health and growth of tea plantations.
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Affiliation(s)
- Ankita Chopra
- Department of Biotechnology, Assam University, Silchar, India
| | - Dattatray Mongad
- National Centre for Microbial Resource, National Centre for Cell Science, Pune, India
| | - Surekha Satpute
- Department of Microbiology, Savitribai Phule Pune University, Pune, India
| | | | - Praveen Rahi
- National Centre for Microbial Resource, National Centre for Cell Science, Pune, India.
- Institut Pasteur, Université Paris Cité, Biological Resource Center of Institut Pasteur (CRBIP), Paris, France.
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4
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Current Techniques to Study Beneficial Plant-Microbe Interactions. Microorganisms 2022; 10:microorganisms10071380. [PMID: 35889099 PMCID: PMC9317800 DOI: 10.3390/microorganisms10071380] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 06/28/2022] [Accepted: 07/05/2022] [Indexed: 02/04/2023] Open
Abstract
Many different experimental approaches have been applied to elaborate and study the beneficial interactions between soil bacteria and plants. Some of these methods focus on changes to the plant and others are directed towards assessing the physiology and biochemistry of the beneficial plant growth-promoting bacteria (PGPB). Here, we provide an overview of some of the current techniques that have been employed to study the interaction of plants with PGPB. These techniques include the study of plant microbiomes; the use of DNA genome sequencing to understand the genes encoded by PGPB; the use of transcriptomics, proteomics, and metabolomics to study PGPB and plant gene expression; genome editing of PGPB; encapsulation of PGPB inoculants prior to their use to treat plants; imaging of plants and PGPB; PGPB nitrogenase assays; and the use of specialized growth chambers for growing and monitoring bacterially treated plants.
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5
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Pennerman KK, Yin G, Bennett JW. Eight-carbon volatiles: prominent fungal and plant interaction compounds. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:487-497. [PMID: 34727164 DOI: 10.1093/jxb/erab438] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 09/24/2021] [Indexed: 06/13/2023]
Abstract
Signaling via volatile organic compounds (VOCs) has historically been studied mostly by entomologists; however, botanists and mycologists are increasingly aware of the physiological potential of chemical communication in the gas phase. Most research to date focuses on the observed effects of VOCs on different organisms such as differential growth or metabolite production. However, with the increased interest in volatile signaling, more researchers are investigating the molecular mechanisms for these effects. Eight-carbon VOCs are among the most prevalent and best-studied fungal volatiles. Therefore, this review emphasizes examples of eight-carbon VOCs affecting plants and fungi. These compounds display different effects that include growth suppression in both plants and fungi, induction of defensive behaviors such as accumulation of mycotoxins, phytohormone signaling cascades, and the inhibition of spore and seed germination. Application of '-omics' and other next-generation sequencing techniques is poised to decipher the mechanistic basis of volatiles in plant-fungal communication.
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Affiliation(s)
- Kayla K Pennerman
- Joint Institute for Food Safety and Applied Nutrition, University of Maryland, College Park, MD 20742, USA
- United States Department of Agriculture, Toxicology and Mycotoxin Research Unit, Athens, GA 30605, USA
| | - Guohua Yin
- United States Department of Agriculture, Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Peoria, IL 61604, USA
- Department of Plant Biology, Rutgers University, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Joan W Bennett
- Department of Plant Biology, Rutgers University, The State University of New Jersey, New Brunswick, NJ 08901, USA
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6
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Patel N, Curtis JC, Plotkin BJ. Insulin Regulation of Escherichia coli Abiotic Biofilm Formation: Effect of Nutrients and Growth Conditions. Antibiotics (Basel) 2021; 10:antibiotics10111349. [PMID: 34827287 PMCID: PMC8615133 DOI: 10.3390/antibiotics10111349] [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: 09/15/2021] [Revised: 10/21/2021] [Accepted: 11/02/2021] [Indexed: 11/23/2022] Open
Abstract
Escherichia coli plays an important role in biofilm formation across a wide array of disease and ecological settings. Insulin can function as an adjuvant in the regulation of biofilm levels. The modulation of insulin-regulated biofilm formation by environmental conditions has not been previously described. In the present study, the effects that various environmental growth conditions and nutrients have on insulin-modulated levels of biofilm production were measured. Micropipette tips were incubated with E. coli ATCC® 25922™ in a Mueller Hinton broth (MH), or a yeast nitrogen base with 1% peptone (YNBP), which was supplemented with glucose, lactose, galactose and/or insulin (Humulin®-R). The incubation conditions included a shaking or static culture, at 23 °C or 37 °C. After incubation, the biofilm production was calculated per CFU. At 23 °C, the presence of insulin increased biofilm formation. The amount of biofilm formation was highest in glucose > galactose >> lactose, while the biofilm levels decreased in shaking cultures, except for galactose (3-fold increase; 0.1% galactose and 20 μU insulin). At 37 °C, regardless of condition, there was more biofilm formation/CFU under static conditions in YNBP than in MH, except for the MH containing galactose. E. coli biofilm formation is influenced by aeration, temperature, and insulin concentration in combination with the available sugars.
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Affiliation(s)
- Nina Patel
- Department of Microbiology and Immunology, College of Osteopathic Medicine, Midwestern University, Downers Grove, IL 60515, USA; (N.P.); (J.C.C.)
- Feinberg School of Medicine, Northwestern University, Chicago, IL 60625, USA
| | - Jeremy C. Curtis
- Department of Microbiology and Immunology, College of Osteopathic Medicine, Midwestern University, Downers Grove, IL 60515, USA; (N.P.); (J.C.C.)
| | - Balbina J. Plotkin
- Department of Microbiology and Immunology, College of Osteopathic Medicine, Midwestern University, Downers Grove, IL 60515, USA; (N.P.); (J.C.C.)
- Correspondence:
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7
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Schoenborn AA, Yannarell SM, Wallace ED, Clapper H, Weinstein IC, Shank EA. Defining the Expression, Production, and Signaling Roles of Specialized Metabolites during Bacillus subtilis Differentiation. J Bacteriol 2021; 203:e0033721. [PMID: 34460312 PMCID: PMC8544424 DOI: 10.1128/jb.00337-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/11/2021] [Indexed: 11/20/2022] Open
Abstract
Bacterial specialized (or secondary) metabolites are structurally diverse molecules that mediate intra- and interspecies interactions by altering growth and cellular physiology and differentiation. Bacillus subtilis, a Gram-positive model bacterium commonly used to study biofilm formation and sporulation, has the capacity to produce more than 10 specialized metabolites. Some of these B. subtilis specialized metabolites have been investigated for their role in facilitating cellular differentiation, but only rarely has the behavior of multiple metabolites been simultaneously investigated. In this study, we explored the interconnectivity of differentiation (biofilm and sporulation) and specialized metabolites in B. subtilis. Specifically, we interrogated how development influences specialized metabolites and vice versa. Using the sporulation-inducing medium DSM, we found that the majority of the specialized metabolites examined are expressed and produced during biofilm formation and sporulation. Additionally, we found that six of these metabolites (surfactin, ComX, bacillibactin, bacilysin, subtilosin A, and plipastatin) are necessary signaling molecules for proper progression of B. subtilis differentiation. This study further supports the growing body of work demonstrating that specialized metabolites have essential physiological functions as cell-cell communication signals in bacteria. IMPORTANCE Bacterially produced specialized metabolites are frequently studied for their potential use as antibiotics and antifungals. However, a growing body of work has suggested that the antagonistic potential of specialized metabolites is not their only function. Here, using Bacillus subtilis as our model bacterium, we demonstrated that developmental processes such as biofilm formation and sporulation are tightly linked to specialized metabolite gene expression and production. Additionally, under our differentiation-inducing conditions, six out of the nine specialized metabolites investigated behave as intraspecific signals that impact B. subtilis physiology and influence biofilm formation and sporulation. Our work supports the viewpoint that specialized metabolites have a clear role as cell-cell signaling molecules within differentiated populations of bacteria.
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Affiliation(s)
- Alexi A. Schoenborn
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sarah M. Yannarell
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - E. Diane Wallace
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Haley Clapper
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Ilon C. Weinstein
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Elizabeth A. Shank
- Program in Systems Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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8
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Luzak V, López-Escobar L, Siegel TN, Figueiredo LM. Cell-to-Cell Heterogeneity in Trypanosomes. Annu Rev Microbiol 2021; 75:107-128. [PMID: 34228491 DOI: 10.1146/annurev-micro-040821-012953] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Recent developments in single-cell and single-molecule techniques have revealed surprising levels of heterogeneity among isogenic cells. These advances have transformed the study of cell-to-cell heterogeneity into a major area of biomedical research, revealing that it can confer essential advantages, such as priming populations of unicellular organisms for future environmental stresses. Protozoan parasites, such as trypanosomes, face multiple and often hostile environments, and to survive, they undergo multiple changes, including changes in morphology, gene expression, and metabolism. But why does only a subset of proliferative cells differentiate to the next life cycle stage? Why do only some bloodstream parasites undergo antigenic switching while others stably express one variant surface glycoprotein? And why do some parasites invade an organ while others remain in the bloodstream? Building on extensive research performed in bacteria, here we suggest that biological noise can contribute to the fitness of eukaryotic pathogens and discuss the importance of cell-to-cell heterogeneity in trypanosome infections. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Vanessa Luzak
- Division of Experimental Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich 82152, Germany.,Biomedical Center, Division of Physiological Chemistry, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich 82152, Germany
| | - Lara López-Escobar
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal;
| | - T Nicolai Siegel
- Division of Experimental Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich 82152, Germany.,Biomedical Center, Division of Physiological Chemistry, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich 82152, Germany
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal;
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9
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Patel K, Rodriguez C, Stabb EV, Hagen SJ. Wavelike propagation of quorum activation through a spatially distributed bacterial population under natural regulation. Phys Biol 2021; 18. [PMID: 34114973 DOI: 10.1088/1478-3975/ac02ac] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 05/18/2021] [Indexed: 11/11/2022]
Abstract
Many bacteria communicate using diffusible pheromone signals known as autoinducers. When the autoinducer concentration reaches a threshold, which requires a minimum population density or 'quorum', the bacteria activate specific gene regulatory pathways. Simple diffusion of autoinducer can activate quorum-dependent pathways in cells that are located at substantial distances from the secreting source. However, modeling has predicted that autoinducer diffusion, coupled with positive feedback regulation in autoinducer synthesis, could also allow a quorum-regulated behavior to spread more rapidly through a population by moving as a self-sustaining front at constant speed. Here we show that such propagation can occur in a population of bacteria whose quorum pathway operates under its own natural regulation. We find that in unstirred populations ofVibrio fischeri, introduction of autoinducer at one location triggers a wavelike traveling front of natural bioluminescence. The front moves with a well-defined speed ∼2.5 mm h-1, eventually outrunning the slower diffusional spreading of the initial stimulus. Consistent with predictions from modeling, the wave travels until late in growth, when population-wide activation occurs due to basal autoinducer production. Subsequent rounds of waves, including waves propagating in the reverse direction, can also be observed late in the growth ofV.fischeriunder natural regulation. Using an engineered,lac-dependent strain, we show that local stimuli other than autoinducers can also elicit a self-sustaining, propagating response. Our data show that the wavelike dynamics predicted by simple mathematical models of quorum signaling are readily detected in bacterial populations functioning under their own natural regulation, and that other, more complex traveling phenomena are also present. Because a traveling wave can substantially increase the efficiency of intercellular communication over macroscopic distances, our data indicate that very efficient modes of communication over distance are available to unmixed populations ofV.fischeriand other microbes.
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Affiliation(s)
- Keval Patel
- Physics Department, University of Florida, Gainesville, FL 32611-8440, United States of America
| | - Coralis Rodriguez
- Department of Microbiology, University of Georgia, Athens, GA 30602, United States of America
| | - Eric V Stabb
- Department of Microbiology, University of Georgia, Athens, GA 30602, United States of America.,Biological Sciences, College of Liberal Arts and Sciences, University of Illinois, Chicago, IL 60607, United States of America
| | - Stephen J Hagen
- Physics Department, University of Florida, Gainesville, FL 32611-8440, United States of America
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10
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The establishment of the CBE launched biofilms as a field of specialized research. Biofilm 2021; 2:100020. [PMID: 33447806 PMCID: PMC7798467 DOI: 10.1016/j.bioflm.2020.100020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/25/2019] [Accepted: 02/01/2020] [Indexed: 01/17/2023] Open
Abstract
The Center for Biofilm Engineering was the first center of excellence focused on biofilms and was originally funded through the Engineering Research Center Program from the U.S. National Science Foundation. After almost 30 years, biofilm continues to be a stand-alone scientific topic of inquiry that has broad implications for fundamental and applied science and engineering of bio-systems. However, much remains to be done, not only for research discovery but also education and outreach, to increase and grow the biofilm paradigm as well as our understanding of the microbial world.
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11
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Huang Y, Lu Z, Jiang T, Zeng Y, Zeng Y, Chen B. Oxygen availability affects the synthesis of quorum sensing signal in the facultative anaerobe Novosphingobium pentaromativorans US6-1. Appl Microbiol Biotechnol 2021; 105:1191-1201. [PMID: 33439275 DOI: 10.1007/s00253-021-11089-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 12/13/2020] [Accepted: 01/03/2021] [Indexed: 01/01/2023]
Abstract
Bacterial populations rely on quorum sensing (QS) to coordinate their behaviors and are often challenged by the fluctuation in oxygen concentrations in their habitats. Oxygen is a crucial factor that affects bacterial metabolism in multiple ways. However, little is known about whether and how oxygen availability affects QS activities. To fill this gap, we used the facultative anaerobe Novosphingobium pentaromativorans US6-1 as a model system, and observed that the QS signal acyl homoserine-lactones (AHLs) were produced only in anoxic environments, such as biofilm, or liquid medium that initially contained less than 2 mg/L dissolved oxygen, but not in highly oxic environments. Comparative transcriptome analysis revealed that oxygen availability significantly affected the physiological activities in US6-1, including fatty acid metabolism, oxidative phosphorylation, citrate cycle, QS activities, and flagellar assembly. The absence of AHLs in the oxic culture was not due to degradation, but to the very low expression of the AHL synthase gene novI. High concentration of NADH during the middle log phase under static cultivation may be a trigger for AHL synthesis. This is the first report that production of AHLs is coupled with anoxic metabolism in a facultative anaerobe, which extends our knowledge on factors affecting bacterial QS occurrence. KEY POINTS: • AHL production is anoxic cultivation related. • Oxygen availability affects AHL synthesis by influencing novI expression. • Oxygen availability changes many metabolism activities including NADH production.
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Affiliation(s)
- Yili Huang
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Bulding NongB, Hangzhou, 310058, China.
| | - Zejia Lu
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Bulding NongB, Hangzhou, 310058, China
| | - Tingting Jiang
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Bulding NongB, Hangzhou, 310058, China
| | - Yonghui Zeng
- Department of Environmental Science, Aarhus University, 4000, Roskilde, Denmark
| | - Yanhua Zeng
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Bulding NongB, Hangzhou, 310058, China
| | - Baoliang Chen
- Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Bulding NongB, Hangzhou, 310058, China
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12
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Melander RJ, Basak AK, Melander C. Natural products as inspiration for the development of bacterial antibiofilm agents. Nat Prod Rep 2020; 37:1454-1477. [PMID: 32608431 PMCID: PMC7677205 DOI: 10.1039/d0np00022a] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Natural products have historically been a rich source of diverse chemical matter with numerous biological activities, and have played an important role in drug discovery in many areas including infectious disease. Synthetic and medicinal chemistry have been, and continue to be, important tools to realize the potential of natural products as therapeutics and as chemical probes. The formation of biofilms by bacteria in an infection setting is a significant factor in the recalcitrance of many bacterial infections, conferring increased tolerance to many antibiotics and to the host immune response, and as yet there are no approved therapeutics for combatting biofilm-based bacterial infections. Small molecules that interfere with the ability of bacteria to form and maintain biofilms can overcome antibiotic tolerance conferred by the biofilm phenotype, and have the potential to form combination therapies with conventional antibiotics. Many natural products with anti-biofilm activity have been identified from plants, microbes, and marine life, including: elligic acid glycosides, hamamelitannin, carolacton, skyllamycins, promysalin, phenazines, bromoageliferin, flustramine C, meridianin D, and brominated furanones. Total synthesis and medicinal chemistry programs have facilitated structure confirmation, identification of critical structural motifs, better understanding of mechanistic pathways, and the development of more potent, more accessible, or more pharmacologically favorable derivatives of anti-biofilm natural products.
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Affiliation(s)
- Roberta J Melander
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
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13
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Guzman JPMD, De las Alas TPL, Lucban MC, Sevilla CEC. Green tea ( Camellia sinensis) extract inhibits biofilm formation in acyl homoserine lactone-producing, antibiotic-resistant Morganella morganii isolated from Pasig River, Philippines. Heliyon 2020; 6:e05284. [PMID: 33134581 PMCID: PMC7586116 DOI: 10.1016/j.heliyon.2020.e05284] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 08/12/2020] [Accepted: 10/14/2020] [Indexed: 12/25/2022] Open
Abstract
The drastic development of urban districts around the world has caused changes in the environment, specifically on metropolitan waterways such as the Pasig River in the Philippines. These significant changes resulted in diversity of microorganisms and their mechanisms employed such as antibiotic resistance and their communication system or quorum sensing (QS). In this study, four bacterial isolates from Pasig River, identified as Aeromonas salmonicida, Acinetobacter sp., Morganella morganii, and Citrobacter freundii, were observed to employ short-chain acyl homoserine lactone (AHL) as their signalling molecule based on in vitro assays using the biosensor strain Chromobacterium violaceum CV026. Furthermore, M. morganii isolate was shown to be resistant to chloramphenicol. This poses a significant threat not just to public health but also to the aquatic life present in the river. Thus, green tea (Camellia sinensis) extract was tested for its capability to inhibit in vitro biofilm formation in M. morganii, as well as the short-chain acyl homoserine lactone QS system using C. violaceum ATCC 12472. Results showed that the extract significantly (p < 0.05) inhibited biofilm formation in M. morganii at as low as 62.5 μg/mL (31.55%). Increasing the concentration (500 μg/mL) did not significantly (p > 0.05) enhance the activity (41.21%). Furthermore, the extract also inhibited pigmentation in C. violaceum ATCC 12472, suggesting QS inhibition. This study adds into record the production of short-chain AHLs by Aeromonas salmonicida, Acinetobacter sp., Morganella morganii, and Citrobacter freundii, as well as the potential of green tea extract as inhibitor of biofilm formation in antibiotic-resistant M. morganii possibly through QS inhibition.
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Affiliation(s)
- John Paul Matthew D. Guzman
- The Graduate School, University of Santo Tomas, Manila, Philippines
- Environment and Biotechnology Division, Industrial Technology Development Institute, Department of Science and Technology, Taguig City, Philippines
| | - Trisha Pamela L. De las Alas
- The Graduate School, University of Santo Tomas, Manila, Philippines
- Globetek Science Foundation, Inc., Makati City, Philippines
| | - Margie C. Lucban
- The Graduate School, University of Santo Tomas, Manila, Philippines
| | - Christine Eden C. Sevilla
- The Graduate School, University of Santo Tomas, Manila, Philippines
- Service Laboratory, Food and Nutrition Research Institute, Department of Science and Technology, Taguig City, Philippines
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14
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A Model Roseobacter, Ruegeria pomeroyi DSS-3, Employs a Diffusible Killing Mechanism To Eliminate Competitors. mSystems 2020; 5:5/4/e00443-20. [PMID: 32788406 PMCID: PMC7426152 DOI: 10.1128/msystems.00443-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Roseobacter clade is a group of alphaproteobacteria that have diverse metabolic and regulatory capabilities. They are abundant in marine environments and have a substantial role in marine ecology and biogeochemistry. However, interactions between roseobacters and other bacterioplankton have not been extensively explored. In this study, we identify a killing mechanism in the model roseobacter Ruegeria pomeroyi DSS-3 by coculturing it with a group of phylogenetically diverse bacteria. The killing mechanism is diffusible and occurs when cells are grown both on surfaces and in suspension and is dependent on cell density. A screen of random transposon mutants revealed that the killing phenotype, as well as resistance to killing, require genes within an ∼8-kb putative gamma-butyrolactone synthesis gene cluster, which resembles similar pheromone-sensing systems in actinomycetes that regulate secondary metabolite production, including antimicrobials. Transcriptomics revealed the gene cluster is highly upregulated in wild-type DSS-3 compared to a nonkiller mutant when grown in liquid coculture with a roseobacter target. Our findings show that R. pomeroyi has the capability to eliminate closely and distantly related competitors, providing a mechanism to alter the community structure and function in its native habitats.IMPORTANCE Bacteria carry out critical ecological and biogeochemical processes and form the foundations of ecosystems. Identifying the factors that influence microbial community composition and the functional capabilities encoded within them is key to predicting how microbes impact an ecosystem. Because microorganisms must compete for limited space and nutrients to promote their own propagation, they have evolved diverse mechanisms to outcompete or kill competitors. However, the genes and regulatory strategies that promote such competitive abilities are largely underexplored, particularly in free-living marine bacteria. Here, genetics and omics techniques are used to investigate how a model marine bacterium is capable of quickly eliminating natural competitors in coculture. We determined that a previously uncharacterized horizontally acquired gene cluster is required for this bacterium to kill diverse competitors. This work represents an important step toward understanding the mechanisms bacterial populations can use to become dominant members in marine microbial communities.
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15
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Aframian N, Eldar A. A Bacterial Tower of Babel: Quorum-Sensing Signaling Diversity and Its Evolution. Annu Rev Microbiol 2020; 74:587-606. [PMID: 32680450 DOI: 10.1146/annurev-micro-012220-063740] [Citation(s) in RCA: 31] [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
Quorum sensing is a process in which bacteria secrete and sense a diffusible molecule, thereby enabling bacterial groups to coordinate their behavior in a density-dependent manner. Quorum sensing has evolved multiple times independently, utilizing different molecular pathways and signaling molecules. A common theme among many quorum-sensing families is their wide range of signaling diversity-different variants within a family code for different signal molecules with a cognate receptor specific to each variant. This pattern of vast allelic polymorphism raises several questions-How do different signaling variants interact with one another? How is this diversity maintained? And how did it come to exist in the first place? Here we argue that social interactions between signaling variants can explain the emergence and persistence of signaling diversity throughout evolution. Finally, we extend the discussion to include cases where multiple diverse systems work in concert in a single bacterium.
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Affiliation(s)
- Nitzan Aframian
- Faculty of Life Sciences, School of Molecular Cell Biology and Biotechnology, Tel-Aviv University, 6997801 Tel-Aviv, Israel; ,
| | - Avigdor Eldar
- Faculty of Life Sciences, School of Molecular Cell Biology and Biotechnology, Tel-Aviv University, 6997801 Tel-Aviv, Israel; ,
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16
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Asif M, Imran M. Quorum Sensing Inhibition: Current Advances of the Natural Antimicrobial Agents. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2020. [DOI: 10.1134/s1068162019060049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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Chen D, Li J, Chen H, Zhang L, Zhang H, Ma Y. Electroosmotic Flow Behavior of Viscoelastic LPTT Fluid in a Microchannel. MICROMACHINES 2019; 10:E881. [PMID: 31847473 PMCID: PMC6952799 DOI: 10.3390/mi10120881] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 11/26/2019] [Accepted: 12/10/2019] [Indexed: 12/27/2022]
Abstract
In many research works, the fluid medium in electroosmosis is considered to be a Newtonian fluid, while the polymer solutions and biological fluids used in biomedical fields mostly belong to the non-Newtonian category. Based on the finite volume method (FVM), the electroosmotic flow (EOF) of viscoelastic fluids in near-neutral (pH = 7.5) solution considering four ions (K+, Cl-, H+, OH-) is numerically studied, as well as the viscoelastic fluids' flow characteristics in a microchannel described by the Linear Phan-Thien-Tanner (LPTT) constitutive model under different conditions, including the electrical double layer (EDL) thickness, the Weissenberg number (Wi), the viscosity ratio and the polymer extensibility parameters. When the EDL does not overlap, the velocity profiles for both Newtonian and viscoelastic fluids are plug-like and increase sharply near the charged wall. Compared with Newtonian fluid at Wi = 3, the viscoelastic fluid velocity increases by 5 times and 9 times, respectively, under the EDL conditions of kH = 15 and kH = 250, indicating the shear thinning behavior of LPTT fluid. Shear stress obviously depends on the viscosity ratio and different Wi number conditions. The EOF is also enhanced by the increase (decrease) in polymer extensibility parameters (viscosity ratio). When the extensibility parameters are large, the contribution to velocity is gradually weakened.
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Affiliation(s)
- Dilin Chen
- School of Energy and Power Engineering, Wuhan University of Technology, Wuhan 430070, China; (D.C.); (H.C.); (L.Z.)
| | - Jie Li
- School of Energy and Power Engineering, Wuhan University of Technology, Wuhan 430070, China; (D.C.); (H.C.); (L.Z.)
| | - Haiwen Chen
- School of Energy and Power Engineering, Wuhan University of Technology, Wuhan 430070, China; (D.C.); (H.C.); (L.Z.)
| | - Lai Zhang
- School of Energy and Power Engineering, Wuhan University of Technology, Wuhan 430070, China; (D.C.); (H.C.); (L.Z.)
| | - Hongna Zhang
- Institut Franco-Chinois de l’Energie Nucléaire, Sun Yat-sen University, Zhuhai 519000, China
| | - Yu Ma
- Institut Franco-Chinois de l’Energie Nucléaire, Sun Yat-sen University, Zhuhai 519000, China
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18
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Çam S, Brinkmeyer R. The effects of temperature, pH, and iron on biofilm formation by clinical versus environmental strains of Vibrio vulnificus. Folia Microbiol (Praha) 2019; 65:557-566. [DOI: 10.1007/s12223-019-00761-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 11/18/2019] [Indexed: 01/30/2023]
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19
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Eze EC, El Zowalaty ME. Combined Effects Of Low Incubation Temperature, Minimal Growth Medium, And Low Hydrodynamics Optimize Acinetobacter baumannii Biofilm Formation. Infect Drug Resist 2019; 12:3523-3536. [PMID: 31814741 PMCID: PMC6863185 DOI: 10.2147/idr.s203919] [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] [Received: 02/02/2019] [Accepted: 06/19/2019] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Biofilm formation is an important virulence factor expressed by Acinetobacter baumannii. It shields and protects microbial cells from host immune responses, antibiotics, and other anti-infectives. Its effects on Acinetobacter baumannii infection treatments notwithstanding, important environmental factors that influence its formation have not been fully investigated. METHODS Biofilm formation was assessed using the qualitative modified Congo red assay and quantitative microtiter plate methods. The combined effect of temperature, medium and shear force was determined by measuring adherence (OD570 nm) in microtiter plate after incubation at 26°C, 30°C, and 37°C when biofilm-grown cells were cultured in the presence of minimal nutrient medium (EAOB) and nutrient-rich medium (TSB) without or with agitation at 50 rpm. Antibiotics susceptibility of meropenem, imipenem, and ciprofloxacin were tested with Kirby-Bauer disc method. P<0.05 was considered statistically significant in all the tests. RESULTS A noticeable variation in adherence was observed among the isolates cultured with both media. Biofilm forming capacity of the isolates range from 0.09-0.33. The majority of the isolates had their relative biofilm-forming capacity significantly (p<0.05) higher than the positive control, Acinetobacter baumannii ATCC 19606. The biofilm biomass during growth in nutrient-rich medium (TSB) without shaking was significantly different (p<0.05; Tukey's test) among the three temperatures tested compared with when it was cultured in EAOB without shaking. A positive correlation was observed between biofilm formation and resistance to imipenem (r=0.2889; p=0.05). There was a statistically significant difference among the median of the three source groups (p<0.05) compared with the median between the source groups. CONCLUSION This observation extended further the view that A. baumannii biofilm formation is enhanced when nutrient-poor medium is used at room temperature (26°C) with or without agitation compared to growth at 37°C.
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Affiliation(s)
- Emmanuel C Eze
- Medical Microbiology and Infection Control, School of Laboratory Medicine and Medical Sciences, College of Health Science, University of KwaZulu-Natal, Durban, South Africa
| | - Mohamed E El Zowalaty
- Virology and Microbiology Research Group, School of Health Sciences, University of KwaZulu-Natal, Durban4000, South Africa
- Infectious Diseases and Anti-Infective Research Group, College of Pharmacy, University of Sharjah, Sharjah27272, UAE
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20
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Wang J, Liu Q, Wu B, Zhao F, Ma S, Hu H, Zhang X, Ren H. Quorum sensing signaling distribution during the development of full-scale municipal wastewater treatment biofilms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 685:28-36. [PMID: 31174122 DOI: 10.1016/j.scitotenv.2019.05.249] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/30/2019] [Accepted: 05/17/2019] [Indexed: 06/09/2023]
Abstract
Acylated homoserine lactone (AHL)-mediated quorum sensing (QS) is ecologically important in multi-species systems in laboratory-scale studies; however, little is known about QS in the biofilm formation process in full-scale wastewater treatment plants, which is driven by multiple environmental variables. Here, a model integrated fixed-film-activated sludge system was employed in full-scale municipal wastewater treatment plant to investigate the AHL distribution during the biofilm development process in response to variable environmental factors. The whole biofilm development process can be divided into three phases: initial biofilm attachment process (week 1 to 3), biofilm development and mature phase (week 4 to 6), and biofilm detachment and reformation process (week 7 to 17). N-decanoyl-DL-homoserine lactone (C10-HSL) and N-dodecanoyl-DL-homoserine lactone (C12-HSL) presented high concentrations during the biofilm formation process, which was closely related with the biofilm initial attachment process. The AHL concentration in biofilms was higher than in activated sludge. During the initial attachment process, tryptophan and protein-like substances related to biological substance were strongly positively correlated with all detected AHL concentrations (p < 0.05). Three environmental variables (total nitrogen, pH, and Na+) were closely related to AHL distribution in municipal wastewater biofilms. High wastewater pH was found to contribute to a low AHL concentration. AHLs in the biofilm were significantly (p < 0.01) influenced by the concentration of Na+, and higher concentrations of Na+ (10.84-18.58 mg/L) in wastewater treatment plants potentially contribute to the biofilm formation processes. In addition, bacteria with nitrogen removal ability showed QS functionality. The results of this study indicate that AHL-based regulation of tryptophan and protein-like substances related to biological substance production was significantly influenced by the surrounding chemical environment, which has been underestimated in previous studies. AHL-mediated QS potentially suggests a novel solution for the advanced AHL-based regulation of the biofilm development processes.
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Affiliation(s)
- Jinfeng Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Qiuju Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Bing Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Fuzheng Zhao
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Sijia Ma
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Haidong Hu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Xuxiang Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Hongqiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China.
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21
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Zaytseva YV, Sidorov AV, Marakaev OA, Khmel IA. Plant-Microbial Interactions Involving Quorum Sensing Regulation. Microbiology (Reading) 2019. [DOI: 10.1134/s0026261719040131] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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22
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Preparation and Formula Analysis of Anti-Biofouling Titania–Polyurea Spray Coating with Nano/Micro-Structure. COATINGS 2019. [DOI: 10.3390/coatings9090560] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This paper proposes the preparation and formula analysis of anti-biofouling Titania–polyurea (TiO2–SPUA) spray coating, which uses nano-scale antibacterial and photocatalytic agents, titanium dioxide, to construct regularly hydrophobic surface texture on the polyurea coating system. Through formulating analysis of anti-biofouling performance, it is found the causal factors include antibacterial TiO2, surface wettability and morphology in order of their importance. The most optimized formula group is able to obtain uniform surface textures, high contact angle (91.5°), low surface energy (32.5 mJ/m2), and strong hardness (74 A). Moreover, this newly fabricated coating can effectively prevent Pseudomonas aeruginosa and biofilm from enriching on the surface, and there is no toxins release from the coating itself, which makes it eco-friendly, even after long-time exposure. These studies provide insights to the relative importance of physiochemical properties of Titania–polyurea spray coatings for further use in marine, as well as bio medical engineering.
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23
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Wickramasinghe NN, Ravensdale J, Coorey R, Chandry SP, Dykes GA. The Predominance of Psychrotrophic Pseudomonads on Aerobically Stored Chilled Red Meat. Compr Rev Food Sci Food Saf 2019; 18:1622-1635. [DOI: 10.1111/1541-4337.12483] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 06/27/2019] [Accepted: 07/02/2019] [Indexed: 01/05/2023]
Affiliation(s)
- Nirmani N. Wickramasinghe
- School of Public HealthCurtin Univ. Perth Western Australia 6845 Australia
- Dept. of Agriculture and FoodCSIRO Werribee Victoria 3030 Australia
| | - Joshua Ravensdale
- School of Public HealthCurtin Univ. Perth Western Australia 6845 Australia
| | - Ranil Coorey
- School of Molecular an Health SciencesCurtin Univ. Perth Western Australia 6845 Australia
| | - Scott P. Chandry
- Dept. of Agriculture and FoodCSIRO Werribee Victoria 3030 Australia
| | - Gary A. Dykes
- School of Public HealthCurtin Univ. Perth Western Australia 6845 Australia
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24
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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: 13] [Impact Index Per Article: 2.6] [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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25
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Charlesworth JC, Watters C, Wong HL, Visscher PT, Burns BP. Isolation of novel quorum-sensing active bacteria from microbial mats in Shark Bay Australia. FEMS Microbiol Ecol 2019; 95:5382036. [PMID: 30877766 DOI: 10.1093/femsec/fiz035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 03/15/2019] [Indexed: 11/13/2022] Open
Abstract
Quorum sensing is a potent system of genetic control allowing phenotypes to be coordinated across localized communities. In this study, quorum sensing systems in Shark Bay microbial mats were delineated using a targeted approach analyzing whole mat extractions as well as the creation of an isolate library. A library of 165 isolates from different mat types were screened using the AHL biosensor E. coli MT102. Based on sequence identity 30 unique isolates belonging to Proteobacteria, Actinobacteria and Firmicutes were found to activate the AHL biosensor, suggesting AHLs or analogous compounds were potentially present. Several of the isolates have not been shown previously to produce signal molecules, particularly the members of the Actinobacteria and Firmicutes phyla including Virgibacillus, Halobacillius, Microbacterium and Brevibacterium. These active isolates were further screened using thin-layer chromatography (TLC) providing putative identities of AHL molecules present within the mat communities. Nine isolates were capable of producing several spots of varying sizes after TLC separation, suggesting the presence of multiple signalling molecules. This study is the first to delineate AHL-based signalling in the microbial mats of Shark Bay, and suggests quorum sensing may play a role in the ecosphysiological coordination of complex phenotypes across microbial mat communities.
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Affiliation(s)
- James C Charlesworth
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, 2052, Australia.,Australian Centre for Astrobiology, University of New South Wales, Sydney, 2052, Australia
| | - Cara Watters
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, 2052, Australia.,Australian Centre for Astrobiology, University of New South Wales, Sydney, 2052, Australia
| | - Hon Lun Wong
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, 2052, Australia.,Australian Centre for Astrobiology, University of New South Wales, Sydney, 2052, Australia
| | - Pieter T Visscher
- Australian Centre for Astrobiology, University of New South Wales, Sydney, 2052, Australia.,Department of Marine Sciences, University of Connecticut, Storrs, 06269, CT, USA
| | - Brendan P Burns
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, 2052, Australia.,Australian Centre for Astrobiology, University of New South Wales, Sydney, 2052, Australia
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26
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Lora-Tamayo J, Murillo O, Ariza J. Clinical Use of Colistin in Biofilm-Associated Infections. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1145:181-195. [PMID: 31364079 DOI: 10.1007/978-3-030-16373-0_13] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Biofilm is an adaptive bacterial strategy whereby microorganisms become encased in a complex glycoproteic matrix. The low concentration of oxygen and nutrients in this environment leads to heterogeneous phenotypic changes in the bacteria, with antimicrobial tolerance being of paramount importance. As with other antibiotics, the activity of colistin is impaired by biofilm-embedded bacteria. Therefore, the recommendation for administering high doses in combination with a second drug, indicated for planktonic infections, remains valid in this setting. Notably, colistin has activity against metabolically inactive biofilm-embedded cells located in the inner layers of the biofilm structure. This is opposite and complementary to the activity of other antimicrobials that are able to kill metabolically active cells in the outer layers of the biofilm. Several experimental models have shown a higher activity of colistin when used in combination with other agents, and have reported that this can avoid the emergence of colistin-resistant subpopulations. Most experience of colistin in biofilm-associated infections comes from patients with cystic fibrosis, where the use of nebulized colistin allows high concentrations to reach the site of the infection. However, limited clinical experience is available in other scenarios, such as osteoarticular infections or device-related central nervous system infections caused by multi-drug resistant microorganisms. In the latter scenario, the use of intraventricular or intrathecal colistin also permits high local concentrations and good clinical results. Overall, the efficacy of intravenous colistin seems to be poor, but its association with a second antimicrobial significantly increases the response rate. Given its activity against inner bioflm-embedded cells, its possible role in combination with other antibiotics, beyond last-line therapy situations, should be further explored.
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Affiliation(s)
- Jaime Lora-Tamayo
- Department of Internal Medicine, Hospital Universitario 12 de Octubre, Madrid, Spain.
| | - Oscar Murillo
- Department of Infectious Diseases, Hospital Universitario de Bellvitge, Barcelona, Spain
| | - Javier Ariza
- Department of Infectious Diseases, Hospital Universitario de Bellvitge, Barcelona, Spain
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27
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Puga CH, Dahdouh E, SanJose C, Orgaz B. Listeria monocytogenes Colonizes Pseudomonas fluorescens Biofilms and Induces Matrix Over-Production. Front Microbiol 2018; 9:1706. [PMID: 30108564 PMCID: PMC6080071 DOI: 10.3389/fmicb.2018.01706] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/09/2018] [Indexed: 12/26/2022] Open
Abstract
In food facilities, biofilms or their debris might act as helpers for attracting free floating microorganisms. In this sense, Pseudomonas fluorescens, a dense biofilm producer frequently isolated from food contact surfaces, could be a good candidate for sheltering other microorganisms, such as Listeria monocytogenes. The main objective of this work was to evaluate the ability of L. monocytogenes to colonize pre-established Pseudomonas biofilms. For this, the movement throughout mature Pseudomonas biofilms of a green fluorescent protein (GFP) - tagged strain of L. monocytogenes was tracked for 24 h by confocal laser scanning microscopy (CLSM). Moreover, in order to check the effect of the incorporation of Listeria on the overall matrix production, attached populations of both microorganisms and total biomass (cells + matrix) of the resulting biofilms were measured over time. Planktonic cells of L. monocytogenes efficiently migrated to preformed P. fluorescens biofilms. Moreover, they moved preferentially toward the bottom layers of these structures, suggesting some kind of tropism. When preformed P. fluorescens biofilms were conditioning the surfaces, the L. monocytogenes attached population was on average, 1-2 Log higher than when this organism grew on bare coupons. Furthermore, the arrival of L. monocytogenes to the already established P. fluorescens biofilms led to a matrix over-production. Indeed, biomass values [optical density (OD595nm)] of the resulting biofilms were double those of the ordinary L. monocytogenes-P. fluorescens mixed biofilms (1.40 vs. 0.6). The fact that L. monocytogenes cells accumulate in the bottom layers of preformed biofilms provides this microorganism an extra protection toward physical-chemical damages. This might partly explain why this microorganism can persist in food industry environments.
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Affiliation(s)
- Carmen H. Puga
- Department of Food Science and Technology, Faculty of Veterinary, University Complutense of Madrid, Madrid, Spain
| | - Elias Dahdouh
- Department of Animal Health, Faculty of Veterinary, University Complutense of Madrid, Madrid, Spain
| | - Carmen SanJose
- Department of Food Science and Technology, Faculty of Veterinary, University Complutense of Madrid, Madrid, Spain
| | - Belen Orgaz
- Department of Food Science and Technology, Faculty of Veterinary, University Complutense of Madrid, Madrid, Spain
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28
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Magana M, Sereti C, Ioannidis A, Mitchell CA, Ball AR, Magiorkinis E, Chatzipanagiotou S, Hamblin MR, Hadjifrangiskou M, Tegos GP. Options and Limitations in Clinical Investigation of Bacterial Biofilms. Clin Microbiol Rev 2018; 31:e00084-16. [PMID: 29618576 PMCID: PMC6056845 DOI: 10.1128/cmr.00084-16] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteria can form single- and multispecies biofilms exhibiting diverse features based upon the microbial composition of their community and microenvironment. The study of bacterial biofilm development has received great interest in the past 20 years and is motivated by the elegant complexity characteristic of these multicellular communities and their role in infectious diseases. Biofilms can thrive on virtually any surface and can be beneficial or detrimental based upon the community's interplay and the surface. Advances in the understanding of structural and functional variations and the roles that biofilms play in disease and host-pathogen interactions have been addressed through comprehensive literature searches. In this review article, a synopsis of the methodological landscape of biofilm analysis is provided, including an evaluation of the current trends in methodological research. We deem this worthwhile because a keyword-oriented bibliographical search reveals that less than 5% of the biofilm literature is devoted to methodology. In this report, we (i) summarize current methodologies for biofilm characterization, monitoring, and quantification; (ii) discuss advances in the discovery of effective imaging and sensing tools and modalities; (iii) provide an overview of tailored animal models that assess features of biofilm infections; and (iv) make recommendations defining the most appropriate methodological tools for clinical settings.
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Affiliation(s)
- Maria Magana
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
| | - Christina Sereti
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Microbiology, Thriassio General Hospital, Attiki, Greece
| | - Anastasios Ioannidis
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Nursing, Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese, Sparta, Greece
| | - Courtney A Mitchell
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Anthony R Ball
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
| | - Emmanouil Magiorkinis
- Department of Hygiene, Epidemiology and Medical Statistics, Medical School, University of Athens, Athens-Goudi, Greece
| | | | - Michael R Hamblin
- Harvard-MIT Division of Health Science and Technology, Cambridge, Massachusetts, USA
- Department of Dermatology, Harvard Medical School, Boston, Massachusetts, USA
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Maria Hadjifrangiskou
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - George P Tegos
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
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Kalantar M, Mardanpour MM, Yaghmaei S. A novel model for predicting bioelectrochemical performance of microsized-MFCs by incorporating bacterial chemotaxis parameters and simulation of biofilm formation. Bioelectrochemistry 2018; 122:51-60. [PMID: 29554553 DOI: 10.1016/j.bioelechem.2018.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 02/25/2018] [Accepted: 03/10/2018] [Indexed: 11/18/2022]
Abstract
Bacterial transport parameters play a fundamental role in microbial population dynamics, biofilm formation and bacteria dispersion. In this study, the novel model was extended based on the capability of microsized microbial fuel cells (MFCs) as amperometric biosensors to predict the cells' chemotactic and bioelectrochemical properties. The model prediction results coincide with the experimental data of Shewanella oneidensis and chemotaxis mutant of P. aeruginosa bdlA and pilT strains, indicating the complementary role of numerical predictions for bioscreening applications of microsized MFCs. Considering the general mechanisms for electron transfer, substrate biodegradation, microbial growth and bacterial dispersion are the main features of the presented model. In addition, the genetic algorithm method was implemented by minimizing the objective function to estimate chemotaxis properties of the different strains. Microsized MFC performance was assessed by analyzing the microbial activity in the biofilm and the anolyte.
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Affiliation(s)
- Mohammad Kalantar
- Faculty of Chemical Engineering, Tarbiat Modares University, Tehran, Iran.
| | - Mohammad Mahdi Mardanpour
- Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran; Technology and Innovation Group, Research Institute of Petroleum Industry, Tehran, Iran
| | - Soheila Yaghmaei
- Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran
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Ricker EB, Al-Jaafari H, Bader TM, Hundley BS, Nuxoll E. Thermal shock susceptibility and regrowth of Pseudomonas aeruginosa biofilms. Int J Hyperthermia 2018; 34:168-176. [PMID: 29498312 PMCID: PMC6150600 DOI: 10.1080/02656736.2017.1347964] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Biofilms on implanted medical devices cause thousands of patients each year to undergo multiple surgeries to remove and replace the implant, driving billions of dollars in increased health care costs due to the lack of viable treatment options for in situ biofilm eradication. Remotely activated localised heating is under investigation to mitigate these biofilms; however, little is known about the temperatures required to kill the biofilms. To better understand the required parameters this study investigated the thermal susceptibility of biofilms as a function of their fluidic and chemical environment during growth, as well as their propensity for regrowth following thermal shock. Pseudomonas aeruginosa biofilms were cultured in shaker plate fluidic conditions in four different growth media, then thermally shocked at various temperatures and exposure times. Biofilms were re-incubated to determine their regrowth potential following thermal shocks of various intensities. Results indicate that growth media has little impact on thermal susceptibility, while fluidic conditions strongly influence susceptibility to modest thermal shocks. This effect disappears, however, with increasingly aggressive shocks, reducing biofilm populations by up to 5 orders of magnitude. Regrowth studies indicate a critical post-shock bacterial loading (∼103 CFU/cm2) below which the biofilms were no longer viable, while biofilms above that loading slowly regrew to their previous population density.
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Affiliation(s)
- Erica B. Ricker
- Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA, USA
| | - Haydar Al-Jaafari
- Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA, USA
- Department of Chemical Engineering, University of Technology, Baghdad, Iraq
| | - Trigg M. Bader
- Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA, USA
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Bryce S. Hundley
- Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA, USA
| | - Eric Nuxoll
- Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA, USA
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W Patt M, Conte L, Blaha M, J Plotkin B. Steroid hormones as interkingdom signaling molecules: Innate immune function and microbial colonization modulation. AIMS MOLECULAR SCIENCE 2018. [DOI: 10.3934/molsci.2018.1.117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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32
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Side DD, Nassisi V, Pennetta C, Alifano P, Di Salvo M, Talà A, Chechkin A, Seno F, Trovato A. Bacterial bioluminescence onset and quenching: a dynamical model for a quorum sensing-mediated property. ROYAL SOCIETY OPEN SCIENCE 2017; 4:171586. [PMID: 29308273 PMCID: PMC5750040 DOI: 10.1098/rsos.171586] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 11/09/2017] [Indexed: 06/07/2023]
Abstract
We present an effective dynamical model for the onset of bacterial bioluminescence, one of the most studied quorum sensing-mediated traits. Our model is built upon simple equations that describe the growth of the bacterial colony, the production and accumulation of autoinducer signal molecules, their sensing within bacterial cells, and the ensuing quorum activation mechanism that triggers bioluminescent emission. The model is directly tested to quantitatively reproduce the experimental distributions of photon emission times, previously measured for bacterial colonies of Vibrio jasicida, a luminescent bacterium belonging to the Harveyi clade, growing in a highly drying environment. A distinctive and novel feature of the proposed model is bioluminescence 'quenching' after a given time elapsed from activation. Using an advanced fitting procedure based on the simulated annealing algorithm, we are able to infer from the experimental observations the biochemical parameters used in the model. Such parameters are in good agreement with the literature data. As a further result, we find that, at least in our experimental conditions, light emission in bioluminescent bacteria appears to originate from a subtle balance between colony growth and quorum activation due to autoinducers diffusion, with the two phenomena occurring on the same time scale. This finding is consistent with a negative feedback mechanism previously reported for Vibrio harveyi.
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Affiliation(s)
- Domenico Delle Side
- Dipartimento di Matematica e Fisica ‘Ennio De Giorgi’, Università del Salento, Lecce, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Lecce, Lecce, Italy
| | - Vincenzo Nassisi
- Dipartimento di Matematica e Fisica ‘Ennio De Giorgi’, Università del Salento, Lecce, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Lecce, Lecce, Italy
| | - Cecilia Pennetta
- Dipartimento di Matematica e Fisica ‘Ennio De Giorgi’, Università del Salento, Lecce, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Lecce, Lecce, Italy
| | - Pietro Alifano
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, Lecce, Italy
| | - Marco Di Salvo
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, Lecce, Italy
| | - Adelfia Talà
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, Lecce, Italy
| | - Aleksei Chechkin
- Akhiezer Institute for Theoretical Physics, Kharkov Institute of Physics and Technology, Kharkov 61108, Ukraine
- Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam, Germany
- Dipartimento di Fisica e Astronomia ‘Galileo Galilei’, Università di Padova, Padova, Italy
| | - Flavio Seno
- Dipartimento di Fisica e Astronomia ‘Galileo Galilei’, Università di Padova, Padova, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova, Italy
| | - Antonio Trovato
- Dipartimento di Fisica e Astronomia ‘Galileo Galilei’, Università di Padova, Padova, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova, Italy
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Singh PK, Bartalomej S, Hartmann R, Jeckel H, Vidakovic L, Nadell CD, Drescher K. Vibrio cholerae Combines Individual and Collective Sensing to Trigger Biofilm Dispersal. Curr Biol 2017; 27:3359-3366.e7. [PMID: 29056457 PMCID: PMC5678073 DOI: 10.1016/j.cub.2017.09.041] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 07/19/2017] [Accepted: 09/19/2017] [Indexed: 01/07/2023]
Abstract
Bacteria can generate benefits for themselves and their kin by living in multicellular, matrix-enclosed communities, termed biofilms, which are fundamental to microbial ecology and the impact bacteria have on the environment, infections, and industry [1, 2, 3, 4, 5, 6]. The advantages of the biofilm mode of life include increased stress resistance and access to concentrated nutrient sources [3, 7, 8]. However, there are also costs associated with biofilm growth, including the metabolic burden of biofilm matrix production, increased resource competition, and limited mobility inside the community [9, 10, 11]. The decision-making strategies used by bacteria to weigh the costs between remaining in a biofilm or actively dispersing are largely unclear, even though the dispersal transition is a central aspect of the biofilm life cycle and critical for infection transmission [12, 13, 14]. Using a combination of genetic and novel single-cell imaging approaches, we show that Vibrio cholerae integrates dual sensory inputs to control the dispersal response: cells use the general stress response, which can be induced via starvation, and they also integrate information about the local cell density and molecular transport conditions in the environment via the quorum sensing apparatus. By combining information from individual (stress response) and collective (quorum sensing) avenues of sensory input, biofilm-dwelling bacteria can make robust decisions to disperse from large biofilms under distress, while preventing premature dispersal when biofilm populations are small. These insights into triggers and regulators of biofilm dispersal are a key step toward actively inducing biofilm dispersal for technological and medical applications, and for environmental control of biofilms. Cells in V. cholerae biofilms decide to disperse by combining two sensory mechanisms Quorum sensing and RpoS provide information on different environmental parameters Integration of both sensory inputs yields robust and optimal dispersal decisions
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Affiliation(s)
- Praveen K Singh
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse 10, Marburg 35043, Germany
| | - Sabina Bartalomej
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse 10, Marburg 35043, Germany
| | - Raimo Hartmann
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse 10, Marburg 35043, Germany
| | - Hannah Jeckel
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse 10, Marburg 35043, Germany; Department of Physics, Philipps-Universität Marburg, Renthof 6, Marburg 35032, Germany
| | - Lucia Vidakovic
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse 10, Marburg 35043, Germany
| | - Carey D Nadell
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse 10, Marburg 35043, Germany
| | - Knut Drescher
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse 10, Marburg 35043, Germany; Department of Physics, Philipps-Universität Marburg, Renthof 6, Marburg 35032, Germany.
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Bacon CW, Hinton DM, Mitchell TR. Is Quorum Signaling by Mycotoxins a New Risk-Mitigating Strategy for Bacterial Biocontrol of Fusarium verticillioides and Other Endophytic Fungal Species? JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:7071-7080. [PMID: 27958725 DOI: 10.1021/acs.jafc.6b03861] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Bacterial endophytes are used as biocontrol organisms for plant pathogens such as the maize endophyte Fusarium verticillioides and its production of fumonisin mycotoxins. However, such applications are not always predictable and efficient. In this work, we hypothesize and review work that quorum sensing inhibitors are produced either by fungi or by pathogenic bacteria for competitive purposes, altering the efficiency of the biocontrol organisms. Recently, quorum sensing inhibitors have been isolated from several fungi, including Fusarium species, three of which are mycotoxins. Thus, we further postulate that other mycotoxins are inhibitors or quenching metabolites that prevent the protective abilities and activities of endophytic biocontrol bacteria within intercellular spaces. To test the aforementioned suppositions, we review work detailing the use of bioassay bacteria for several mycotoxins for quorum activity. We specifically focus on the quorum use of endophytic bacteria as biocontrols for mycotoxic fungal endophytes, such as the Fusarium species and the fumonisin mycotoxins.
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Affiliation(s)
- Charles W Bacon
- U.S. National Poultry Research Center, Toxicology & Mycotoxin Research Unit, Russell Research Center, Agricultural Research Service, U.S. Department of Agriculture , Athens, Georgia 30605, United States
| | - Dorothy M Hinton
- U.S. National Poultry Research Center, Toxicology & Mycotoxin Research Unit, Russell Research Center, Agricultural Research Service, U.S. Department of Agriculture , Athens, Georgia 30605, United States
| | - Trevor R Mitchell
- U.S. National Poultry Research Center, Toxicology & Mycotoxin Research Unit, Russell Research Center, Agricultural Research Service, U.S. Department of Agriculture , Athens, Georgia 30605, United States
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Decho AW, Gutierrez T. Microbial Extracellular Polymeric Substances (EPSs) in Ocean Systems. Front Microbiol 2017; 8:922. [PMID: 28603518 PMCID: PMC5445292 DOI: 10.3389/fmicb.2017.00922] [Citation(s) in RCA: 251] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 05/08/2017] [Indexed: 12/13/2022] Open
Abstract
Microbial cells (i.e., bacteria, archaea, microeukaryotes) in oceans secrete a diverse array of large molecules, collectively called extracellular polymeric substances (EPSs) or simply exopolymers. These secretions facilitate attachment to surfaces that lead to the formation of structured 'biofilm' communities. In open-water environments, they also lead to formation of organic colloids, and larger aggregations of cells, called 'marine snow.' Secretion of EPS is now recognized as a fundamental microbial adaptation, occurring under many environmental conditions, and one that influences many ocean processes. This relatively recent realization has revolutionized our understanding of microbial impacts on ocean systems. EPS occur in a range of molecular sizes, conformations and physical/chemical properties, and polysaccharides, proteins, lipids, and even nucleic acids are actively secreted components. Interestingly, however, the physical ultrastructure of how individual EPS interact with each other is poorly understood. Together, the EPS matrix molecules form a three-dimensional architecture from which cells may localize extracellular activities and conduct cooperative/antagonistic interactions that cannot be accomplished efficiently by free-living cells. EPS alter optical signatures of sediments and seawater, and are involved in biogeomineral precipitation and the construction of microbial macrostructures, and horizontal-transfers of genetic information. In the water-column, they contribute to the formation of marine snow, transparent exopolymer particles (TEPs), sea-surface microlayer biofilm, and marine oil snow. Excessive production of EPS occurs during later-stages of phytoplankton blooms as an excess metabolic by product and releases a carbon pool that transitions among dissolved-, colloidal-, and gel-states. Some EPS are highly labile carbon forms, while other forms appear quite refractory to degradation. Emerging studies suggest that EPS contribute to efficient trophic-transfer of environmental contaminants, and may provide a protective refugia for pathogenic cells within marine systems; one that enhances their survival/persistence. Finally, these secretions are prominent in 'extreme' environments ranging from sea-ice communities to hypersaline systems to the high-temperatures/pressures of hydrothermal-vent systems. This overview summarizes some of the roles of exopolymer in oceans.
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Affiliation(s)
- Alan W. Decho
- Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, ColumbiaSC, United States
| | - Tony Gutierrez
- School of Engineering and Physical Sciences, Heriot-Watt UniversityEdinburgh, United Kingdom
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Peptide modification results in the formation of a dimer with a 60-fold enhanced antimicrobial activity. PLoS One 2017; 12:e0173783. [PMID: 28296935 PMCID: PMC5351969 DOI: 10.1371/journal.pone.0173783] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 02/27/2017] [Indexed: 12/21/2022] Open
Abstract
Cationic antimicrobial peptides (CAMPs) occur naturally in numerous organisms and are considered as a class of antibiotics with promising potential against multi-resistant bacteria. Herein, we report a strategy that can lead to the discovery of novel small CAMPs with greatly enhanced antimicrobial activity and retained antibiofilm potential. We geared our efforts towards i) the N-terminal cysteine functionalization of a previously reported small synthetic cationic peptide (peptide 1037, KRFRIRVRV-NH2), ii) its dimerization through a disulfide bond, and iii) a preliminary antimicrobial activity assessment of the newly prepared dimer against Pseudomonas aeruginosa and Burkholderia cenocepacia, pathogens responsible for the formation of biofilms in lungs of individuals with cystic fibrosis. This dimer is of high interest as it does not only show greatly enhanced bacterial growth inhibition properties compared to its pep1037 precursor (up to 60 times), but importantly, also displays antibiofilm potential at sub-MICs. Our results suggest that the reported dimer holds promise for its use in future adjunctive therapy, in combination with clinically-relevant antibiotics.
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Abstract
Quorum sensing (QS) is a form of chemical communication used by certain bacteria that regulates a wide range of biogeochemically important bacterial behaviors. Although QS was first observed in a marine bacterium nearly four decades ago, only in the past decade has there been a rise in interest in the role that QS plays in the ocean. It has become clear that QS, regulated by signals such as acylated homoserine lactones (AHLs) or furanosyl-borate diesters [autoinducer-2 (AI-2) molecules], is involved in important processes within the marine carbon cycle, in the health of coral reef ecosystems, and in trophic interactions between a range of eukaryotes and their bacterial associates. The most well-studied QS systems in the ocean occur in surface-attached (biofilm) communities and rely on AHL signaling. AHL-QS is highly sensitive to the chemical and biological makeup of the environment and may respond to anthropogenic change, including ocean acidification and rising sea surface temperatures.
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Affiliation(s)
- Laura R Hmelo
- School of Oceanography, University of Washington, Seattle, Washington 98195;
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Perry N, Nelson EM, Timp G. Wiring Together Synthetic Bacterial Consortia to Create a Biological Integrated Circuit. ACS Synth Biol 2016; 5:1421-1432. [PMID: 27346524 DOI: 10.1021/acssynbio.6b00002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The promise of adapting biology to information processing will not be realized until engineered gene circuits, operating in different cell populations, can be wired together to express a predictable function. Here, elementary biological integrated circuits (BICs), consisting of two sets of transmitter and receiver gene circuit modules with embedded memory placed in separate cell populations, were meticulously assembled using live cell lithography and wired together by the mass transport of quorum-sensing (QS) signal molecules to form two isolated communication links (comlinks). The comlink dynamics were tested by broadcasting "clock" pulses of inducers into the networks and measuring the responses of functionally linked fluorescent reporters, and then modeled through simulations that realistically captured the protein production and molecular transport. These results show that the comlinks were isolated and each mimicked aspects of the synchronous, sequential networks used in digital computing. The observations about the flow conditions, derived from numerical simulations, and the biofilm architectures that foster or silence cell-to-cell communications have implications for everything from decontamination of drinking water to bacterial virulence.
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Affiliation(s)
- Nicolas Perry
- University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Edward M. Nelson
- University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Gregory Timp
- University of Notre Dame, Notre Dame, Indiana 46556, United States
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Feraco D, Blaha M, Khan S, Green JM, Plotkin BJ. Host environmental signals and effects on biofilm formation. Microb Pathog 2016; 99:253-263. [DOI: 10.1016/j.micpath.2016.08.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 08/18/2016] [Indexed: 01/04/2023]
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Resilience of bacterial quorum sensing against fluid flow. Sci Rep 2016; 6:33115. [PMID: 27650454 PMCID: PMC5030672 DOI: 10.1038/srep33115] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 08/16/2016] [Indexed: 02/05/2023] Open
Abstract
Quorum sensing (QS) is a population-density dependent chemical process that enables bacteria to communicate based on the production, secretion and sensing of small inducer molecules. While recombinant constructs have been widely used to decipher the molecular details of QS, how those findings translate to natural QS systems has remained an open question. Here, we compare the activation of natural and synthetic Pseudomonas aeruginosa LasI/R QS systems in bacteria exposed to quiescent conditions and controlled flows. Quantification of QS-dependent GFP expression in suspended cultures and in surface-attached microcolonies revealed that QS onset in both systems was similar under quiescent conditions but markedly differed under flow. Moderate flow (Pe > 25) was sufficient to suppress LasI/R QS recombinantly expressed in Escherichia coli, whereas only high flow (Pe > 102) suppressed QS in wild-type P. aeruginosa. We suggest that this difference stems from the differential production of extracellular matrix and that the matrix confers resilience against moderate flow to QS in wild-type organisms. These results suggest that the expression of a biofilm matrix extends the environmental conditions under which QS-based cell-cell communication is effective and that findings from synthetic QS circuits cannot be directly translated to natural systems.
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Myszka K, Schmidt MT, Białas W, Olkowicz M, Leja K, Czaczyk K. Role of gallic and p-coumaric acids in the AHL-dependent expression of flgA gene and in the process of biofilm formation in food-associated Pseudomonas fluorescens KM120. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2016; 96:4037-4047. [PMID: 26710926 DOI: 10.1002/jsfa.7599] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 12/15/2015] [Accepted: 12/18/2015] [Indexed: 06/05/2023]
Abstract
BACKGROUND In the process of Pseudomonas fluorescens biofilm formation, N-acyl-l-homoserine lactone (AHL)-mediated flagella synthesis plays a key role. Inhibition of AHL production may attenuate P. fluorescens biofilm on solid surfaces. This work validated the anti-biofilm properties of p-coumaric and gallic acids via the ability of phenolics to suppress AHL synthesis in P. fluorescens KM120. The dependence between synthesis of AHL molecules, expression of flagella gene (flgA) and the ability of biofilm formation by P. fluorescens KM120 on a stainless steel surface (type 304L) was also investigated. RESULTS Research was carried out in a purpose-built flow cell device. Limitations on AHL synthesis in P. fluorescens KM120 were observed at concentrations of 120 and 240 µmol L(-1) of phenolic acids in medium. At such levels of gallic and p-coumaric acids the ability of P. fluorescens KM120 to synthesize 3-oxo-C6-homoserine lactone (HSL) was not observed. These concentrations caused decreased expression of flgA gene in P. fluorescens KM120. The changes in expression of AHL-dependent flgA gene significantly decreased the rate of microorganism colonization on the stainless steel surface. CONCLUSION Phenolic acids are able to inhibit biofilm formation. The results obtained in the work may help to develop alternative techniques for anti-biofilm treatment in the food industry. © 2015 Society of Chemical Industry.
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Affiliation(s)
- Kamila Myszka
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, Wojska Polskiego 48, PL-60-627, Poznan, Poland
| | - Marcin T Schmidt
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, Wojska Polskiego 48, PL-60-627, Poznan, Poland
| | - Wojciech Białas
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, Wojska Polskiego 48, PL-60-627, Poznan, Poland
| | - Mariola Olkowicz
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, Wojska Polskiego 48, PL-60-627, Poznan, Poland
| | - Katarzyna Leja
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, Wojska Polskiego 48, PL-60-627, Poznan, Poland
| | - Katarzyna Czaczyk
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, Wojska Polskiego 48, PL-60-627, Poznan, Poland
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Huang J, Shi Y, Zeng G, Gu Y, Chen G, Shi L, Hu Y, Tang B, Zhou J. Acyl-homoserine lactone-based quorum sensing and quorum quenching hold promise to determine the performance of biological wastewater treatments: An overview. CHEMOSPHERE 2016; 157:137-151. [PMID: 27213243 DOI: 10.1016/j.chemosphere.2016.05.032] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/21/2016] [Accepted: 05/11/2016] [Indexed: 06/05/2023]
Abstract
Quorum sensing (QS) is a communication process between cells, in which bacteria secrete and sense the specific chemicals, and regulate gene expression in response to population density. Quorum quenching (QQ) blocks QS system, and inhibits gene expression mediating bacterial behaviors. Given the extensive research of acyl-homoserine lactone (AHL) signals, existences and effects of AHL-based QS and QQ in biological wastewater treatments are being subject to high concern. This review summarizes AHL structure, synthesis mode, degradation mechanisms, analytical methods, environmental factors, AHL-based QS and QQ mechanisms. The existences and roles of AHL-based QS and QQ in biomembrane processes, activated sludge processes and membrane bioreactors are summarized and discussed, and corresponding exogenous regulation strategy by selective enhancement of AHL-based QS or QQ coexisting in biological wastewater treatments is suggested. Such strategies including the addition of AHL signals, AHL-producing bacteria as well as quorum quenching enzyme or bacteria can effectively improve wastewater treatment performance without killing or limiting bacterial survival and growth. This review will present the theoretical and practical cognition for bacterial AHL-based QS and QQ, suggest the feasibility of exogenous regulation strategies in biological wastewater treatments, and provide useful information to scientists and engineers who work in this field.
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Affiliation(s)
- Jinhui Huang
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China.
| | - Yahui Shi
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Guangming Zeng
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Yanling Gu
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Guiqiu Chen
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Lixiu Shi
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Yi Hu
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Bi Tang
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Jianxin Zhou
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
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Local and global consequences of flow on bacterial quorum sensing. Nat Microbiol 2016; 1:15005. [PMID: 27571752 DOI: 10.1038/nmicrobiol.2015.5] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 10/01/2015] [Indexed: 12/19/2022]
Abstract
Bacteria use a chemical communication process called quorum sensing (QS) to control collective behaviours such as pathogenesis and biofilm formation(1,2). QS relies on the production, release and group-wide detection of signal molecules called autoinducers. To date, studies of bacterial pathogenesis in well-mixed cultures have revealed virulence factors and the regulatory circuits controlling them, including the overarching role of QS(3). Although flow is ubiquitous to nearly all living systems(4), much less explored is how QS influences pathogenic traits in scenarios that mimic host environments, for example, under fluid flow and in complex geometries. Previous studies(5-7) have shown that sufficiently strong flow represses QS. Nonetheless, it is not known how QS functions under constant or intermittent flow, how it varies within biofilms or as a function of position along a confined flow, or how surface topography (grooves, crevices, pores) influence QS-mediated communication. We explore these questions using two common pathogens, Staphylococcus aureus and Vibrio cholerae. We identify conditions where flow represses QS and other conditions where QS is activated despite flow, including characterizing geometric and topographic features that influence the QS response. Our studies highlight that, under flow, genetically identical cells do not exhibit phenotypic uniformity with respect to QS in space and time, leading to complex patterns of pathogenesis and colonization. Understanding the ramifications of spatially and temporally non-uniform QS responses in realistic environments will be crucial for successful deployment of synthetic pro- and anti-QS strategies.
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Luthuli BB, Purdy GE, Balagaddé FK. Confinement-Induced Drug-Tolerance in Mycobacteria Mediated by an Efflux Mechanism. PLoS One 2015; 10:e0136231. [PMID: 26295942 PMCID: PMC4546595 DOI: 10.1371/journal.pone.0136231] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 07/30/2015] [Indexed: 11/20/2022] Open
Abstract
Tuberculosis (TB) is the world's deadliest curable disease, responsible for an estimated 1.5 million deaths annually. A considerable challenge in controlling this disease is the prolonged multidrug chemotherapy (6 to 9 months) required to overcome drug-tolerant mycobacteria that persist in human tissues, although the same drugs can sterilize genetically identical mycobacteria growing in axenic culture within days. An essential component of TB infection involves intracellular Mycobacterium tuberculosis bacteria that multiply within macrophages and are significantly more tolerant to antibiotics compared to extracellular mycobacteria. To investigate this aspect of human TB, we created a physical cell culture system that mimics confinement of replicating mycobacteria, such as in a macrophage during infection. Using this system, we uncovered an epigenetic drug-tolerance phenotype that appears when mycobacteria are cultured in space-confined bioreactors and disappears in larger volume growth contexts. Efflux mechanisms that are induced in space-confined growth environments contribute to this drug-tolerance phenotype. Therefore, macrophage-induced drug tolerance by mycobacteria may be an effect of confined growth among other macrophage-specific mechanisms.
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Affiliation(s)
- Brilliant B. Luthuli
- KwaZulu-Natal Research Institute for Tuberculosis and HIV, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, 4001, South Africa
| | - Georgiana E. Purdy
- Dept. of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 S. W. Sam Jackson Park Rd., Mail Code L220, Portland, OR, 97239, United States of America
| | - Frederick K. Balagaddé
- KwaZulu-Natal Research Institute for Tuberculosis and HIV, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, 4001, South Africa
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Cell Differentiation in a Bacillus thuringiensis Population during Planktonic Growth, Biofilm Formation, and Host Infection. mBio 2015; 6:e00138-15. [PMID: 25922389 PMCID: PMC4436061 DOI: 10.1128/mbio.00138-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Bacillus thuringiensis (Bt) is armed to complete a full cycle in its insect host. During infection, virulence factors are expressed under the control of the quorum sensor PlcR to kill the host. After the host’s death, the quorum sensor NprR controls a necrotrophic lifestyle, allowing the vegetative cells to use the insect cadaver as a bioincubator and to survive. Only a part of the Bt population sporulates in the insect cadaver, and the precise composition of the whole population and its evolution over time are unknown. Using fluorescent reporters to record gene expression at the single-cell level, we have determined the differentiation course of a Bt population and explored the lineage existing among virulent, necrotrophic, and sporulating cells. The dynamics of cell differentiation were monitored during growth in homogenized medium, biofilm formation, and colonization of insect larvae. We demonstrated that in the insect host and in planktonic culture in rich medium, the virulence, necrotrophism, and sporulation regulators are successively activated in the same cell. In contrast, in biofilms, activation of PlcR is dispensable for NprR activation and we observed a greater heterogeneity than under the other two growth conditions. We also showed that sporulating cells arise almost exclusively from necrotrophic cells. In biofilm and in the insect cadaver, we identified an as-yet-uncharacterized category of cells that do not express any of the reporters used. Overall, we showed that PlcR, NprR, and Spo0A act as interconnected integrators to allow finely tuned adaptation of the pathogen to its environment. Bt is an entomopathogen found ubiquitously in the environment and is a widely used biopesticide. Studies performed at the population level suggest that the infection process of Bt includes three successive steps (virulence, necrotrophism, and sporulation) controlled by different regulators. This study aimed to determine how these phenotypes are activated at the cellular level and if they are switched on in all cells. We used an insect model of infection and biofilms to decipher the cellular differentiation of this bacterium under naturalistic conditions. Our study reveals the connection and lineage existing among virulent, necrotrophic, and sporulating cells. It also shows that the complex conditions encountered in biofilms and during infection generate great heterogeneity inside the population, which might reflect a bet-hedging strategy to ameliorate survival. These data generate new insights into the role of regulatory networks in the adaptation of a pathogen to its host.
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A mathematical model to investigate quorum sensing regulation and its heterogeneity in Pseudomonas syringae on leaves. ECOLOGICAL COMPLEXITY 2015. [DOI: 10.1016/j.ecocom.2014.12.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Nelson EM, Mirsaidov U, Sarveswaran K, Perry N, Kurz V, Timp W, Timp G. Ecology of a Simple Synthetic Biofilm. THE PHYSICAL BASIS OF BACTERIAL QUORUM COMMUNICATION 2015. [DOI: 10.1007/978-1-4939-1402-9_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Langebrake JB, Dilanji GE, Hagen SJ, De Leenheer P. Traveling waves in response to a diffusing quorum sensing signal in spatially-extended bacterial colonies. J Theor Biol 2014; 363:53-61. [DOI: 10.1016/j.jtbi.2014.07.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 06/18/2014] [Accepted: 07/28/2014] [Indexed: 10/24/2022]
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Zimmer BL, May AL, Bhedi CD, Dearth SP, Prevatte CW, Pratte Z, Campagna SR, Richardson LL. Quorum sensing signal production and microbial interactions in a polymicrobial disease of corals and the coral surface mucopolysaccharide layer. PLoS One 2014; 9:e108541. [PMID: 25268348 PMCID: PMC4182479 DOI: 10.1371/journal.pone.0108541] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 08/29/2014] [Indexed: 02/01/2023] Open
Abstract
Black band disease (BBD) of corals is a complex polymicrobial disease considered to be a threat to coral reef health, as it can lead to mortality of massive reef-building corals. The BBD community is dominated by gliding, filamentous cyanobacteria with a highly diverse population of heterotrophic bacteria. Microbial interactions such as quorum sensing (QS) and antimicrobial production may be involved in BBD disease pathogenesis. In this study, BBD (whole community) samples, as well as 199 bacterial isolates from BBD, the surface mucopolysaccharide layer (SML) of apparently healthy corals, and SML of apparently healthy areas of BBD-infected corals were screened for the production of acyl homoserine lactones (AHLs) and for autoinducer-2 (AI-2) activity using three bacterial reporter strains. AHLs were detected in all BBD (intact community) samples tested and in cultures of 5.5% of BBD bacterial isolates. Over half of a subset (153) of the isolates were positive for AI-2 activity. AHL-producing isolates were further analyzed using LC-MS/MS to determine AHL chemical structure and the concentration of (S)-4,5-dihydroxy-2,3-pentanedione (DPD), the biosynthetic precursor of AI-2. C6-HSL was the most common AHL variant detected, followed by 3OC4-HSL. In addition to QS assays, 342 growth challenges were conducted among a subset of the isolates, with 27% of isolates eliciting growth inhibition and 2% growth stimulation. 24% of BBD isolates elicited growth inhibition as compared to 26% and 32% of the bacteria from the two SML sources. With one exception, only isolates that exhibited AI-2 activity or produced DPD inhibited growth of test strains. These findings demonstrate for the first time that AHLs are present in an active coral disease. It is possible that AI-2 production among BBD and coral SML bacteria may structure the microbial communities of both a polymicrobial infection and the healthy coral microbiome.
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Affiliation(s)
- Beth L. Zimmer
- Department of Biological Sciences, Florida International University, Miami, Florida, United States of America
- Atkins North America, Miami, Florida, United States of America
| | - Amanda L. May
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Chinmayee D. Bhedi
- Department of Biological Sciences, Florida International University, Miami, Florida, United States of America
| | - Stephen P. Dearth
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Carson W. Prevatte
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Zoe Pratte
- Department of Biological Sciences, Florida International University, Miami, Florida, United States of America
| | - Shawn R. Campagna
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Laurie L. Richardson
- Department of Biological Sciences, Florida International University, Miami, Florida, United States of America
- * E-mail:
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