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Zappa S, Berne C, Morton Iii RI, Whitfield GB, De Stercke J, Brun YV. The HmrABCX pathway regulates the transition between motile and sessile lifestyles in Caulobacter crescentus by a mechanism independent of hfiA transcription. mBio 2024:e0100224. [PMID: 39230277 DOI: 10.1128/mbio.01002-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 06/03/2024] [Indexed: 09/05/2024] Open
Abstract
During its cell cycle, the bacterium Caulobacter crescentus switches from a motile, free-living state, to a sessile surface-attached cell. During this coordinated process, cells undergo irreversible morphological changes, such as shedding of their polar flagellum and synthesis of an adhesive holdfast at the same pole. In this work, we used genetic screens to identify genes involved in the regulation of the transition from the motile to the sessile lifestyle. We identified a predicted hybrid histidine kinase that inhibits biofilm formation and promotes the motile lifestyle: HmrA (holdfast and motility regulator A). Genetic screens and genomic localization led to the identification of additional genes that form a putative phosphorelay pathway with HmrA. We postulate that the Hmr pathway acts as a rheostat to control the proportion of cells harboring a flagellum or a holdfast in the population. Further genetic analysis suggests that the Hmr pathway impacts c-di-GMP synthesis through the diguanylate cyclase DgcB pathway. Our results also indicate that the Hmr pathway is involved in the regulation of motile to sessile lifestyle transition as a function of various environmental factors: biofilm formation is repressed when excess copper is present and derepressed under non-optimal temperatures. Finally, we provide evidence that the Hmr pathway regulates motility and adhesion without modulating the transcription of the holdfast synthesis regulator HfiA. IMPORTANCE Complex communities attached to a surface, or biofilms, represent the major lifestyle of bacteria in the environment. Such a sessile state enables the inhabitants to be more resistant to adverse environmental conditions. Thus, having a deeper understanding of the underlying mechanisms that regulate the transition between the motile and the sessile states could help design strategies to improve biofilms when they are beneficial or impede them when they are detrimental. For Caulobacter crescentus motile cells, the transition to the sessile lifestyle is irreversible, and this decision is regulated at several levels. In this work, we describe a putative phosphorelay that promotes the motile lifestyle and inhibits biofilm formation, providing new insights into the control of adhesin production that leads to the formation of biofilms.
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Affiliation(s)
- Sébastien Zappa
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, Quebec, Canada
| | - Cécile Berne
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, Quebec, Canada
| | | | - Gregory B Whitfield
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, Quebec, Canada
| | - Jonathan De Stercke
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, Quebec, Canada
| | - Yves V Brun
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, Quebec, Canada
- Department of Biology, Indiana University, Bloomington, Indiana, USA
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Lin Q, Lin S, Fan Z, Liu J, Ye D, Guo P. A Review of the Mechanisms of Bacterial Colonization of the Mammal Gut. Microorganisms 2024; 12:1026. [PMID: 38792855 PMCID: PMC11124445 DOI: 10.3390/microorganisms12051026] [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: 04/18/2024] [Revised: 05/12/2024] [Accepted: 05/15/2024] [Indexed: 05/26/2024] Open
Abstract
A healthy animal intestine hosts a diverse population of bacteria in a symbiotic relationship. These bacteria utilize nutrients in the host's intestinal environment for growth and reproduction. In return, they assist the host in digesting and metabolizing nutrients, fortifying the intestinal barrier, defending against potential pathogens, and maintaining gut health. Bacterial colonization is a crucial aspect of this interaction between bacteria and the intestine and involves the attachment of bacteria to intestinal mucus or epithelial cells through nonspecific or specific interactions. This process primarily relies on adhesins. The binding of bacterial adhesins to host receptors is a prerequisite for the long-term colonization of bacteria and serves as the foundation for the pathogenicity of pathogenic bacteria. Intervening in the adhesion and colonization of bacteria in animal intestines may offer an effective approach to treating gastrointestinal diseases and preventing pathogenic infections. Therefore, this paper reviews the situation and mechanisms of bacterial colonization, the colonization characteristics of various bacteria, and the factors influencing bacterial colonization. The aim of this study was to serve as a reference for further research on bacteria-gut interactions and improving animal gut health.
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Affiliation(s)
- Qingjie Lin
- College of Animal Science, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Fuzhou 350002, China; (Q.L.); (S.L.); (Z.F.)
| | - Shiying Lin
- College of Animal Science, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Fuzhou 350002, China; (Q.L.); (S.L.); (Z.F.)
| | - Zitao Fan
- College of Animal Science, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Fuzhou 350002, China; (Q.L.); (S.L.); (Z.F.)
| | - Jing Liu
- Institute of Animal Husbandry and Veterinary Medicine, Fujian Academy of Agricultural Sciences, Fuzhou 350013, China;
| | - Dingcheng Ye
- Institute of Animal Husbandry and Veterinary Medicine, Fujian Academy of Agricultural Sciences, Fuzhou 350013, China;
| | - Pingting Guo
- College of Animal Science, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Fuzhou 350002, China; (Q.L.); (S.L.); (Z.F.)
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Iaconis A, De Plano LM, Caccamo A, Franco D, Conoci S. Anti-Biofilm Strategies: A Focused Review on Innovative Approaches. Microorganisms 2024; 12:639. [PMID: 38674584 PMCID: PMC11052202 DOI: 10.3390/microorganisms12040639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 03/17/2024] [Accepted: 03/19/2024] [Indexed: 04/28/2024] Open
Abstract
Biofilm (BF) can give rise to systemic infections, prolonged hospitalization times, and, in the worst case, death. This review aims to provide an overview of recent strategies for the prevention and destruction of pathogenic BFs. First, the main phases of the life cycle of BF and maturation will be described to identify potential targets for anti-BF approaches. Then, an approach acting on bacterial adhesion, quorum sensing (QS), and the extracellular polymeric substance (EPS) matrix will be introduced and discussed. Finally, bacteriophage-mediated strategies will be presented as innovative approaches against BF inhibition/destruction.
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Affiliation(s)
- Antonella Iaconis
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (ChiBioFarAm), University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy; (A.I.); (L.M.D.P.); (A.C.)
| | - Laura Maria De Plano
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (ChiBioFarAm), University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy; (A.I.); (L.M.D.P.); (A.C.)
| | - Antonella Caccamo
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (ChiBioFarAm), University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy; (A.I.); (L.M.D.P.); (A.C.)
| | - Domenico Franco
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (ChiBioFarAm), University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy; (A.I.); (L.M.D.P.); (A.C.)
| | - Sabrina Conoci
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (ChiBioFarAm), University of Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy; (A.I.); (L.M.D.P.); (A.C.)
- Department of Chemistry “Giacomo Ciamician”, Alma Mater Studiorum—University of Bologna, 40126 Bologna, Italy
- URT Lab Sens Beyond Nano—CNR-DSFTM, Department of Physical Sciences and Technologies of Matter, University of Messina, Viale F. Stagno D’Alcontres 31, 98166 Messina, Italy
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Zappa S, Berne C, Morton RI, De Stercke J, Brun YV. The HmrABCX pathway regulates the transition between motile and sessile lifestyles in Caulobacter crescentus by a HfiA-independent mechanism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.13.571505. [PMID: 38168291 PMCID: PMC10760086 DOI: 10.1101/2023.12.13.571505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Through its cell cycle, the bacterium Caulobacter crescentus switches from a motile, free-living state, to a sessile surface-attached cell. During this coordinated process, cells undergo irreversible morphological changes, such as shedding of their polar flagellum and synthesis of an adhesive holdfast at the same pole. In this work, we used genetic screens to identify genes involved in the regulation of the motile to sessile lifestyle transition. We identified a predicted hybrid histidine kinase that inhibits biofilm formation and activates the motile lifestyle: HmrA (Holdfast and motility regulator A). Genetic screens and genomic localization led to the identification of additional genes that regulate the proportion of cells harboring an active flagellum or a holdfast and that form a putative phosphorelay pathway with HmrA. Further genetic analysis indicates that the Hmr pathway is independent of the holdfast synthesis regulator HfiA and may impact c-di-GMP synthesis through the diguanylate cyclase DgcB pathway. Finally, we provide evidence that the Hmr pathway is involved in the regulation of sessile-to-motile lifestyle as a function of environmental stresses, namely excess copper and non-optimal temperatures.
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Affiliation(s)
- Sébastien Zappa
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, Québec, CANADA
| | - Cecile Berne
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, Québec, CANADA
| | - Robert I. Morton
- Department of Biology, Indiana University, Bloomington, IN, USA
- Present address: Boston Scientific, Yokneam, Northern, ISRAEL
| | - Jonathan De Stercke
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, Québec, CANADA
- Present address: Unité de Recherche en Biologie des Micro-organismes, Université de Namur, 61 rue de Bruxelles, B-5000 Namur, BELGIUM
| | - Yves V. Brun
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, Montréal, Québec, CANADA
- Department of Biology, Indiana University, Bloomington, IN, USA
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