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Kato H, Okino N, Kijitori H, Izawa Y, Wada Y, Maki M, Yamamoto T, Yano T. Analysis of biofilm and bacterial communities in the towel environment with daily use. Sci Rep 2023; 13:7611. [PMID: 37165063 PMCID: PMC10172380 DOI: 10.1038/s41598-023-34501-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 05/03/2023] [Indexed: 05/12/2023] Open
Abstract
Towels differ remarkably from other textile products in their fibre structure and usage, and microbial behaviours on towels remain underexplored. Thus, we evaluated biofilm formation on towels during use for 6 months in daily life and analysed its relationship with odour, dullness, and laundry habits. The towels exhibited odour and dullness after 2 months of use and biofilm structures were observed over the 6 months, especially in the ground warp part. Polysaccharides, proteins, nucleic acids, and viable counts on the towels increased over time. The microbiota was significantly different from that on human skin and clothing. Several species of Alphaproteobacteria were correlated with dullness intensity and the quantity of biofilm components. Therefore, bacterial species that specifically adapt to the towel fibre environment could form biofilms. Our results demonstrate bacterial diversity in textile products and suggest careful consideration of the textile fibre material, structure, and usage pattern to control bacterial communities.
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Affiliation(s)
- Haruro Kato
- Safety Science Research Laboratories, Kao Corporation, 2606 Ichikai, Haga, Tochigi, 321-3497, Japan
| | - Nagisa Okino
- Household Products Research Laboratories, Kao Corporation, 1334 Minato, Wakayama, Wakayama, 640-8580, Japan
| | - Hiroki Kijitori
- Household Products Research Laboratories, Kao Corporation, 1334 Minato, Wakayama, Wakayama, 640-8580, Japan
| | - Yoshifumi Izawa
- Biological Science Research Laboratory, Kao Corporation, 1334 Minato, Wakayama, Wakayama, 640-8580, Japan
| | - Yasunao Wada
- Household Products Research Laboratories, Kao Corporation, 1334 Minato, Wakayama, Wakayama, 640-8580, Japan
| | - Masataka Maki
- Intellectual Property Organization, Kao Corporation, 1334 Minato, Wakayama, Wakayama, 640-8580, Japan
| | - Takako Yamamoto
- Safety Science Research Laboratories, Kao Corporation, 2606 Ichikai, Haga, Tochigi, 321-3497, Japan
| | - Takehisa Yano
- Safety Science Research Laboratories, Kao Corporation, 2606 Ichikai, Haga, Tochigi, 321-3497, Japan.
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HfaE Is a Component of the Holdfast Anchor Complex That Tethers the Holdfast Adhesin to the Cell Envelope. J Bacteriol 2022; 204:e0027322. [PMID: 36165621 PMCID: PMC9664946 DOI: 10.1128/jb.00273-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Bacteria use adhesins to colonize different surfaces and form biofilms. The species of the Caulobacterales order use a polar adhesin called holdfast, composed of polysaccharides, proteins, and DNA, to irreversibly adhere to surfaces. In Caulobacter crescentus, a freshwater Caulobacterales species, the holdfast is anchored at the cell pole via the holdfast anchor (Hfa) proteins HfaA, HfaB, and HfaD. HfaA and HfaD colocalize with holdfast and are thought to form amyloid-like fibers that anchor holdfast to the cell envelope. HfaB, a lipoprotein, is required for the translocation of HfaA and HfaD to the cell surface. Deletion of the anchor proteins leads to a severe defect in adherence resulting from holdfast not being properly attached to the cell and shed into the medium. This phenotype is greater in a ΔhfaB mutant than in a ΔhfaA ΔhfaD double mutant, suggesting that HfaB has other functions besides the translocation of HfaA and HfaD. Here, we identify an additional HfaB-dependent holdfast anchoring protein, HfaE, which is predicted to be a secreted protein. HfaE is highly conserved among Caulobacterales species, with no predicted function. In planktonic culture, hfaE mutants produce holdfasts and rosettes similar to those produced by the wild type. However, holdfasts from hfaE mutants bind to the surface but are unable to anchor cells, similarly to other anchor mutants. We showed that fluorescently tagged HfaE colocalizes with holdfast and that HfaE forms an SDS-resistant high-molecular-weight species consistent with amyloid fiber formation. We propose that HfaE is a novel holdfast anchor protein and that HfaE functions to link holdfast material to the cell envelope. IMPORTANCE For surface attachment and biofilm formation, bacteria produce adhesins that are composed of polysaccharides, proteins, and DNA. Species of the Caulobacterales produce a specialized polar adhesin, holdfast, which is required for permanent attachment to surfaces. In this study, we evaluate the role of a newly identified holdfast anchor protein, HfaE, in holdfast anchoring to the cell surface in two different members of the Caulobacterales with drastically different environments. We show that HfaE plays an important role in adhesion and biofilm formation in the Caulobacterales. Our results provide insights into bacterial adhesins and how they interact with the cell envelope and surfaces.
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Liu Q, Hao LF, Chen Y, Liu ZC, Xing WW, Zhang C, Fu WL, Xu DG. The Screening and Expression of Polysaccharide Deacetylase from Caulobacter crescentus and Its Function Analysis. Biotechnol Appl Biochem 2022; 70:688-696. [PMID: 35932185 DOI: 10.1002/bab.2390] [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: 08/23/2021] [Accepted: 07/12/2022] [Indexed: 11/06/2022]
Abstract
The bacterium Caulobacter crescentus secretes an adhesive polysaccharide called holdfast which is the known strongest underwater adhesive in nature. The deacetylase encoded by hfs (holdfast synthesis) H gene is a key factor affecting the adhesion of holdfast. Its structure and function are not yet clear, and whether other polysaccharide deacetylases exist in C. crescentus is still unknown. The screening of both HfsH and its structural analogue as well as their purification from the artificial expression products of E. coli. is the first step to clarify these questions. Here, we determined the conserved domains of HfsH via sequence alignment among Carbohydrate Esterase family 4 enzymes and screened out its structural analogue (CC_2574) in C. crescentus. The recombinant HfsH and CC_2574 were effectively expressed in E. coli. Both of them were purified by chromatography from their corresponding productions in E. coli., and were then functionally analyzed. The results indicated that a high deacetylase activity (61.8 U/mg) was observed in recombinant HfsH but not in CC_2574, which suggesting that HfsH might be the irreplaceable gene mediating adhesion of holdfast in C. crescentus. Moreover, the divalent metal ions Zn2+ , Mg2+ , Mn2+ could promote the activity of recombinant HfsH at the concentration from 0.05mM to 1mM, but inhibit its activity when the concentration exceeds 1mM. In sum, our study firstly realized the artificial production of polysaccharide deacetylase HfsH and its structural analogue, and further explored their functions, both of which laid the foundation for the development of new adhesive materials. Expression of polysaccharide deacetylase HfsH promoting the adhesion of holdfast The effects of various metal ions on the deacetylase activity of recombinant HfsH Functional analysis of recombinant polysaccharide deacetylase Screening of functional analogue of HfsH in Caulobacter crescentus based on ts conserved domains This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Qing Liu
- Beijing Institute of Basic Medical Sciences, Beijing, 100850, China
| | - Li-Fang Hao
- College of Pharmaceutical Sciences, Hebei University, Baoding, Hebei, 071002, China
| | - Yao Chen
- Beijing Institute of Basic Medical Sciences, Beijing, 100850, China
| | - Zhong-Cheng Liu
- College of Pharmaceutical Sciences, Hebei University, Baoding, Hebei, 071002, China
| | - Wei-Wei Xing
- Beijing Institute of Basic Medical Sciences, Beijing, 100850, China
| | - Chao Zhang
- Beijing Institute of Basic Medical Sciences, Beijing, 100850, China
| | - Wen-Liang Fu
- Beijing Institute of Basic Medical Sciences, Beijing, 100850, China
| | - Dong-Gang Xu
- Beijing Institute of Basic Medical Sciences, Beijing, 100850, China
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4
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Onyeziri MC, Hardy GG, Natarajan R, Xu J, Reynolds IP, Kim J, Merritt PM, Danhorn T, Hibbing ME, Weisberg AJ, Chang JH, Fuqua C. Dual adhesive unipolar polysaccharides synthesized by overlapping biosynthetic pathways in Agrobacterium tumefaciens. Mol Microbiol 2022; 117:1023-1047. [PMID: 35191101 PMCID: PMC9149101 DOI: 10.1111/mmi.14887] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 01/28/2022] [Accepted: 02/07/2022] [Indexed: 11/29/2022]
Abstract
Agrobacterium tumefaciens is a member of the Alphaproteobacteria that pathogenises plants and associates with biotic and abiotic surfaces via a single cellular pole. A. tumefaciens produces the unipolar polysaccharide (UPP) at the site of surface contact. UPP production is normally surface-contact inducible, but elevated levels of the second messenger cyclic diguanylate monophosphate (cdGMP) bypass this requirement. Multiple lines of evidence suggest that the UPP has a central polysaccharide component. Using an A. tumefaciens derivative with elevated cdGMP and mutationally disabled for other dispensable polysaccharides, a series of related genetic screens have identified a large number of genes involved in UPP biosynthesis, most of which are Wzx-Wzy-type polysaccharide biosynthetic components. Extensive analyses of UPP production in these mutants have revealed that the UPP is composed of two genetically, chemically, and spatially discrete forms of polysaccharide, and that each requires a specific Wzy-type polymerase. Other important biosynthetic, processing, and regulatory functions for UPP production are also revealed, some of which are common to both polysaccharides, and a subset of which are specific to each type. Many of the UPP genes identified are conserved among diverse rhizobia, whereas others are more lineage specific.
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Affiliation(s)
| | - Gail G. Hardy
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Ramya Natarajan
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Jing Xu
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Ian P. Reynolds
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Jinwoo Kim
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Peter M. Merritt
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Thomas Danhorn
- Department of Biology, Indiana University, Bloomington, IN 47405
| | | | - Alexandra J. Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
| | - Jeff H. Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
| | - Clay Fuqua
- Department of Biology, Indiana University, Bloomington, IN 47405
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Nguyen AQ, Nguyen LN, Xu Z, Luo W, Nghiem LD. New insights to the difference in microbial composition and interspecies interactions between fouling layer and mixed liquor in a membrane bioreactor. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2021.120034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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6
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Chepkwony NK, Brun YV. A polysaccharide deacetylase enhances bacterial adhesion in high-ionic-strength environments. iScience 2021; 24:103071. [PMID: 34568792 PMCID: PMC8449245 DOI: 10.1016/j.isci.2021.103071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 07/19/2021] [Accepted: 08/27/2021] [Indexed: 11/30/2022] Open
Abstract
Differences in ionic strength, pH, temperature, shear forces, and other environmental factors impact adhesion, and organisms have evolved various strategies to optimize their adhesins for their specific environmental conditions. Many species of Alphaproteobacteria, including members of the order Caulobacterales, use a polar adhesin, called holdfast, for surface attachment and subsequent biofilm formation in both freshwater and marine environments. Hirschia baltica, a marine member of Caulobacterales, produces a holdfast adhesin that tolerates a drastically higher ionic strength than the holdfast produced by its freshwater relative, Caulobacter crescentus. In this work, we show that the holdfast polysaccharide deacetylase HfsH plays an important role in adherence in high-ionic-strength environments. We show that increasing expression of HfsH improves holdfast binding in high-ionic-strength environments. We conclude that HfsH plays a role in modulating holdfast binding at high ionic strength and hypothesize that this modulation occurs through varied deacetylation of holdfast polysaccharides. The polysaccharide deacetylase HfsH is required for H. baltica adhesion Holdfast polysaccharides in H. baltica ΔhfsH lack cohesive and adhesive properties HfsH expression correlates positively with holdfast binding in high ionic strength HfsH is an important factor for adherence in high-ionic-strength environments
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Affiliation(s)
- Nelson K Chepkwony
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, C.P. 6128, succ. Centre-ville, Montréal, QC H3C 3J7, Canada
| | - Yves V Brun
- Département de microbiologie, infectiologie et immunologie, Université de Montréal, C.P. 6128, succ. Centre-ville, Montréal, QC H3C 3J7, Canada
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7
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Pérez-Burgos M, García-Romero I, Valvano MA, Søgaard Andersen L. Identification of the Wzx flippase, Wzy polymerase and sugar-modifying enzymes for spore coat polysaccharide biosynthesis in Myxococcus xanthus. Mol Microbiol 2020; 113:1189-1208. [PMID: 32064693 DOI: 10.1111/mmi.14486] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/11/2020] [Indexed: 12/28/2022]
Abstract
The rod-shaped cells of Myxococcus xanthus, a Gram-negative deltaproteobacterium, differentiate to environmentally resistant spores upon starvation or chemical stress. The environmental resistance depends on a spore coat polysaccharide that is synthesised by the ExoA-I proteins, some of which are part of a Wzx/Wzy-dependent pathway for polysaccharide synthesis and export; however, key components of this pathway have remained unidentified. Here, we identify and characterise two additional loci encoding proteins with homology to enzymes involved in polysaccharide synthesis and export, as well as sugar modification and show that six of the proteins encoded by these loci are essential for the formation of environmentally resistant spores. Our data support that MXAN_3260, renamed ExoM and MXAN_3026, renamed ExoJ, are the Wzx flippase and Wzy polymerase, respectively, responsible for translocation and polymerisation of the repeat unit of the spore coat polysaccharide. Moreover, we provide evidence that three glycosyltransferases (MXAN_3027/ExoK, MXAN_3262/ExoO and MXAN_3263/ExoP) and a polysaccharide deacetylase (MXAN_3259/ExoL) are important for formation of the intact spore coat, while ExoE is the polyisoprenyl-phosphate hexose-1-phosphate transferase responsible for initiating repeat unit synthesis, likely by transferring N-acetylgalactosamine-1-P to undecaprenyl-phosphate. Together, our data generate a more complete model of the Exo pathway for spore coat polysaccharide biosynthesis and export.
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Affiliation(s)
- María Pérez-Burgos
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | | | - Miguel A Valvano
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Lotte Søgaard Andersen
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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8
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Comparative Analysis of Ionic Strength Tolerance between Freshwater and Marine Caulobacterales Adhesins. J Bacteriol 2019; 201:JB.00061-19. [PMID: 30858293 DOI: 10.1128/jb.00061-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 03/08/2019] [Indexed: 11/20/2022] Open
Abstract
Bacterial adhesion is affected by environmental factors, such as ionic strength, pH, temperature, and shear forces. Therefore, marine bacteria must have developed adhesins with different compositions and structures than those of their freshwater counterparts to adapt to their natural environment. The dimorphic alphaproteobacterium Hirschia baltica is a marine budding bacterium in the clade Caulobacterales H. baltica uses a polar adhesin, the holdfast, located at the cell pole opposite the reproductive stalk, for surface attachment and cell-cell adhesion. The holdfast adhesin has been best characterized in Caulobacter crescentus, a freshwater member of the Caulobacterales, and little is known about holdfast compositions and properties in marine Caulobacterales Here, we use H. baltica as a model to characterize holdfast properties in marine Caulobacterales We show that freshwater and marine Caulobacterales use similar genes in holdfast biogenesis and that these genes are highly conserved among the species in the two genera. We determine that H. baltica produces a larger holdfast than C. crescentus and that the holdfasts have different chemical compositions, as they contain N-acetylglucosamine and galactose monosaccharide residues and proteins but lack DNA. Finally, we show that H. baltica holdfasts tolerate higher ionic strength than those of C. crescentus We conclude that marine Caulobacterales holdfasts have physicochemical properties that maximize binding in high-ionic-strength environments.IMPORTANCE Most bacteria spend a large part of their life spans attached to surfaces, forming complex multicellular communities called biofilms. Bacteria can colonize virtually any surface, and therefore, they have adapted to bind efficiently in very different environments. In this study, we compare the adhesive holdfasts produced by the freshwater bacterium C. crescentus and a relative, the marine bacterium H. baltica We show that H. baltica holdfasts have a different morphology and chemical composition and tolerate high ionic strength. Our results show that the H. baltica holdfast is an excellent model to study the effect of ionic strength on adhesion and provides insights into the physicochemical properties required for adhesion in the marine environment.
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9
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Composition of the Holdfast Polysaccharide from Caulobacter crescentus. J Bacteriol 2019; 201:JB.00276-19. [PMID: 31209074 DOI: 10.1128/jb.00276-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 06/06/2019] [Indexed: 02/07/2023] Open
Abstract
Surface colonization is central to the lifestyles of many bacteria. Exploiting surface niches requires sophisticated systems for sensing and attaching to solid materials. Caulobacter crescentus synthesizes a polysaccharide-based adhesin known as the holdfast at one of its cell poles, which enables tight attachment to exogenous surfaces. The genes required for holdfast biosynthesis have been analyzed in detail, but difficulties in isolating analytical quantities of the adhesin have limited efforts to characterize its chemical structure. In this report, we describe a method to extract the holdfast from C. crescentus cultures and present a survey of its carbohydrate content. Glucose, 3-O-methylglucose, mannose, N-acetylglucosamine, and xylose were detected in our extracts. Our results provide evidence that the holdfast contains a 1,4-linked backbone of glucose, mannose, N-acetylglucosamine, and xylose that is decorated with branches at the C-6 positions of glucose and mannose. By defining the monosaccharide components in the polysaccharide, our work establishes a framework for characterizing enzymes in the holdfast pathway and provides a broader understanding of how polysaccharide adhesins are built.IMPORTANCE To colonize solid substrates, bacteria often deploy dedicated adhesins that facilitate attachment to surfaces. Caulobacter crescentus initiates surface colonization by secreting a carbohydrate-based adhesin called the holdfast. Because little is known about the chemical makeup of the holdfast, the pathway for its biosynthesis and the physical basis for its unique adhesive properties are poorly understood. This study outlines a method to extract the C. crescentus holdfast and describes the monosaccharide components contained within the adhesive matrix. The composition analysis adds to our understanding of the chemical basis for holdfast attachment and provides missing information needed to characterize enzymes in the biosynthetic pathway.
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10
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Thompson MA, Onyeziri MC, Fuqua C. Function and Regulation of Agrobacterium tumefaciens Cell Surface Structures that Promote Attachment. Curr Top Microbiol Immunol 2019; 418:143-184. [PMID: 29998422 PMCID: PMC6330146 DOI: 10.1007/82_2018_96] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Agrobacterium tumefaciens attaches stably to plant host tissues and abiotic surfaces. During pathogenesis, physical attachment to the site of infection is a prerequisite to infection and horizontal gene transfer to the plant. Virulent and avirulent strains may also attach to plant tissue in more benign plant associations, and as with other soil microbes, to soil surfaces in the terrestrial environment. Although most A. tumefaciens virulence functions are encoded on the tumor-inducing plasmid, genes that direct general surface attachment are chromosomally encoded, and thus this process is not obligatorily tied to virulence, but is a more fundamental capacity. Several different cellular structures are known or suspected to contribute to the attachment process. The flagella influence surface attachment primarily via their propulsive activity, but control of their rotation during the transition to the attached state may be quite complex. A. tumefaciens produces several pili, including the Tad-type Ctp pili, and several plasmid-borne conjugal pili encoded by the Ti and At plasmids, as well as the so-called T-pilus, involved in interkingdom horizontal gene transfer. The Ctp pili promote reversible interactions with surfaces, whereas the conjugal and T-pili drive horizontal gene transfer (HGT) interactions with other cells and tissues. The T-pilus is likely to contribute to physical association with plant tissues during DNA transfer to plants. A. tumefaciens can synthesize a variety of polysaccharides including cellulose, curdlan (β-1,3 glucan), β-1,2 glucan (cyclic and linear), succinoglycan, and a localized polysaccharide(s) that is confined to a single cellular pole and is called the unipolar polysaccharide (UPP). Lipopolysaccharides are also in the outer leaflet of the outer membrane. Cellulose and curdlan production can influence attachment under certain conditions. The UPP is required for stable attachment under a range of conditions and on abiotic and biotic surfaces. Other factors that have been reported to play a role in attachment include the elusive protein called rhicadhesin. The process of surface attachment is under extensive regulatory control and can be modulated by environmental conditions, as well as by direct responses to surface contact. Complex transcriptional and post-transcriptional control circuitry underlies much of the production and deployment of these attachment functions.
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Affiliation(s)
- Melene A Thompson
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | | | - Clay Fuqua
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA.
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A Genome-Wide Analysis of Adhesion in Caulobacter crescentus Identifies New Regulatory and Biosynthetic Components for Holdfast Assembly. mBio 2019; 10:mBio.02273-18. [PMID: 30755507 PMCID: PMC6372794 DOI: 10.1128/mbio.02273-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Due to their intimate physical interactions with the environment, surface polysaccharides are critical determinants of fitness for bacteria. Caulobacter crescentus produces a specialized structure at one of its cell poles called the holdfast that enables attachment to surfaces. Previous studies have shown that the holdfast is composed of carbohydrate-based material and identified a number of genes required for holdfast development. However, incomplete information about its chemical structure, biosynthetic genes, and regulatory principles has limited progress in understanding the mechanism of holdfast synthesis. We leveraged the adhesive properties of the holdfast to perform a saturating screen for genes affecting attachment to cheesecloth over a multiday time course. Using similarities in the temporal profiles of mutants in a transposon library, we defined discrete clusters of genes with related effects on cheesecloth colonization. Holdfast synthesis, flagellar motility, type IV pilus assembly, and smooth lipopolysaccharide (SLPS) production represented key classes of adhesion determinants. Examining these clusters in detail allowed us to predict and experimentally define the functions of multiple uncharacterized genes in both the holdfast and SLPS pathways. In addition, we showed that the pilus and the flagellum control holdfast synthesis separately by modulating the holdfast inhibitor hfiA. This report defines a set of genes contributing to adhesion that includes newly discovered genes required for holdfast biosynthesis and attachment. Our data provide evidence that the holdfast contains a complex polysaccharide with at least four monosaccharides in the repeating unit and underscore the central role of cell polarity in mediating attachment of C. crescentus to surfaces.IMPORTANCE Bacteria routinely encounter biotic and abiotic materials in their surrounding environments, and they often enlist specific behavioral programs to colonize these materials. Adhesion is an early step in colonizing a surface. Caulobacter crescentus produces a structure called the holdfast which allows this organism to attach to and colonize surfaces. To understand how the holdfast is produced, we performed a genome-wide search for genes that contribute to adhesion by selecting for mutants that could not attach to cheesecloth. We discovered complex interactions between genes that mediate surface contact and genes that contribute to holdfast development. Our genetic selection identified what likely represents a comprehensive set of genes required to generate a holdfast, laying the groundwork for a detailed characterization of the enzymes that build this specialized adhesin.
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12
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Stankeviciute G, Miguel AV, Radkov A, Chou S, Huang KC, Klein EA. Differential modes of crosslinking establish spatially distinct regions of peptidoglycan in
Caulobacter crescentus. Mol Microbiol 2019; 111:995-1008. [DOI: 10.1111/mmi.14199] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/02/2019] [Indexed: 11/28/2022]
Affiliation(s)
- Gabriele Stankeviciute
- Center for Computational and Integrative Biology Rutgers University‐Camden Camden NJ 08102USA
| | - Amanda V. Miguel
- Department of Bioengineering Stanford University Stanford CA 94305USA
| | - Atanas Radkov
- Department of Biochemistry and Biophysics University of California San Francisco San Francisco CA 94158USA
| | - Seemay Chou
- Department of Biochemistry and Biophysics University of California San Francisco San Francisco CA 94158USA
- Chan Zuckerberg Biohub San Francisco CA 94158USA
| | - Kerwyn Casey Huang
- Department of Bioengineering Stanford University Stanford CA 94305USA
- Chan Zuckerberg Biohub San Francisco CA 94158USA
- Department of Microbiology and Immunology Stanford University School of Medicine Stanford CA 94305USA
| | - Eric A. Klein
- Center for Computational and Integrative Biology Rutgers University‐Camden Camden NJ 08102USA
- Biology Department Rutgers University‐Camden Camden NJ 08102USA
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13
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Berne C, Ellison CK, Agarwal R, Severin GB, Fiebig A, Morton RI, Waters CM, Brun YV. Feedback regulation of Caulobacter crescentus holdfast synthesis by flagellum assembly via the holdfast inhibitor HfiA. Mol Microbiol 2018; 110:219-238. [PMID: 30079982 DOI: 10.1111/mmi.14099] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2018] [Indexed: 12/23/2022]
Abstract
To permanently attach to surfaces, Caulobacter crescentusproduces a strong adhesive, the holdfast. The timing of holdfast synthesis is developmentally regulated by cell cycle cues. When C. crescentusis grown in a complex medium, holdfast synthesis can also be stimulated by surface sensing, in which swarmer cells rapidly synthesize holdfast in direct response to surface contact. In contrast to growth in complex medium, here we show that when cells are grown in a defined medium, surface contact does not trigger holdfast synthesis. Moreover, we show that in a defined medium, flagellum synthesis and regulation of holdfast production are linked. In these conditions, mutants lacking a flagellum attach to surfaces over time more efficiently than either wild-type strains or strains harboring a paralyzed flagellum. Enhanced adhesion in mutants lacking flagellar components is due to premature holdfast synthesis during the cell cycle and is regulated by the holdfast synthesis inhibitor HfiA. hfiA transcription is reduced in flagellar mutants and this reduction is modulated by the diguanylate cyclase developmental regulator PleD. We also show that, in contrast to previous predictions, flagella are not necessarily required for C. crescentus surface sensing in the absence of flow, and that arrest of flagellar rotation does not stimulate holdfast synthesis. Rather, our data support a model in which flagellum assembly feeds back to control holdfast synthesis via HfiA expression in a c-di-GMP-dependent manner under defined nutrient conditions.
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Affiliation(s)
- Cécile Berne
- Department of Biology, Indiana University, 1001 E. 3rd Street, Bloomington, IN, 47405, USA
| | - Courtney K Ellison
- Department of Biology, Indiana University, 1001 E. 3rd Street, Bloomington, IN, 47405, USA
| | - Radhika Agarwal
- Department of Biology, Indiana University, 1001 E. 3rd Street, Bloomington, IN, 47405, USA.,Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - Geoffrey B Severin
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Aretha Fiebig
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Robert I Morton
- Department of Biology, Indiana University, 1001 E. 3rd Street, Bloomington, IN, 47405, USA
| | - Christopher M Waters
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Yves V Brun
- Department of Biology, Indiana University, 1001 E. 3rd Street, Bloomington, IN, 47405, USA
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Costa OYA, Raaijmakers JM, Kuramae EE. Microbial Extracellular Polymeric Substances: Ecological Function and Impact on Soil Aggregation. Front Microbiol 2018; 9:1636. [PMID: 30083145 PMCID: PMC6064872 DOI: 10.3389/fmicb.2018.01636] [Citation(s) in RCA: 384] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 06/30/2018] [Indexed: 11/15/2022] Open
Abstract
A wide range of microorganisms produce extracellular polymeric substances (EPS), highly hydrated polymers that are mainly composed of polysaccharides, proteins, and DNA. EPS are fundamental for microbial life and provide an ideal environment for chemical reactions, nutrient entrapment, and protection against environmental stresses such as salinity and drought. Microbial EPS can enhance the aggregation of soil particles and benefit plants by maintaining the moisture of the environment and trapping nutrients. In addition, EPS have unique characteristics, such as biocompatibility, gelling, and thickening capabilities, with industrial applications. However, despite decades of research on the industrial potential of EPS, only a few polymers are widely used in different areas, especially in agriculture. This review provides an overview of current knowledge on the ecological functions of microbial EPSs and their application in agricultural soils to improve soil particle aggregation, an important factor for soil structure, health, and fertility.
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Affiliation(s)
- Ohana Y. A. Costa
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
- Institute of Biology, Leiden University, Leiden, Netherlands
| | - Jos M. Raaijmakers
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
- Institute of Biology, Leiden University, Leiden, Netherlands
| | - Eiko E. Kuramae
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
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15
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Favre L, Ortalo-Magné A, Pichereaux C, Gargaros A, Burlet-Schiltz O, Cotelle V, Culioli G. Metabolome and proteome changes between biofilm and planktonic phenotypes of the marine bacterium Pseudoalteromonas lipolytica TC8. BIOFOULING 2018; 34:132-148. [PMID: 29319346 DOI: 10.1080/08927014.2017.1413551] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 11/29/2017] [Indexed: 06/07/2023]
Abstract
A number of bacteria adopt various lifestyles such as planktonic free-living or sessile biofilm stages. This enables their survival and development in a wide range of contrasting environments. With the aim of highlighting specific metabolic shifts between these phenotypes and to improve the overall understanding of marine bacterial adhesion, a dual metabolomics/proteomics approach was applied to planktonic and biofilm cultures of the marine bacterium Pseudoalteromonas lipolytica TC8. The liquid chromatography mass spectrometry (LC-MS) based metabolomics study indicated that membrane lipid composition was highly affected by the culture mode: phosphatidylethanolamine (PEs) derivatives were over-produced in sessile cultures while ornithine lipids (OLs) were more specifically synthesized in planktonic samples. In parallel, differences between proteomes revealed that peptidases, oxidases, transcription factors, membrane proteins and the enzymes involved in histidine biosynthesis were over-expressed in biofilms while proteins involved in heme production, nutrient assimilation, cell division and arginine/ornithine biosynthesis were specifically up-regulated in free-living cells.
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Affiliation(s)
- Laurie Favre
- a MAPIEM EA 4323 , Université de Toulon , Toulon , France
| | | | - Carole Pichereaux
- b Fédération de Recherche FR3450 , CNRS , Toulouse , France
- c Institut de Pharmacologie et de Biologie Structurale, IPBS , Université de Toulouse, CNRS, UPS , Toulouse , France
| | - Audrey Gargaros
- c Institut de Pharmacologie et de Biologie Structurale, IPBS , Université de Toulouse, CNRS, UPS , Toulouse , France
| | - Odile Burlet-Schiltz
- c Institut de Pharmacologie et de Biologie Structurale, IPBS , Université de Toulouse, CNRS, UPS , Toulouse , France
| | - Valérie Cotelle
- d Laboratoire de Recherche en Sciences Végétales , Université de Toulouse, CNRS, UPS , Castanet-Tolosan , France
| | - Gérald Culioli
- a MAPIEM EA 4323 , Université de Toulon , Toulon , France
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16
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More than a Tad: spatiotemporal control of Caulobacter pili. Curr Opin Microbiol 2017; 42:79-86. [PMID: 29161615 DOI: 10.1016/j.mib.2017.10.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 10/20/2017] [Accepted: 10/22/2017] [Indexed: 01/09/2023]
Abstract
The Type IV pilus (T4P) is a powerful and sophisticated bacterial nanomachine involved in numerous cellular processes, including adhesion, DNA uptake and motility. Aside from the well-described subtype T4aP of the Gram-negative genera, including Myxococcus, Pseudomonas and Neisseria, the Tad (tight adherence) pilus secretion system re-shuffles homologous parts from other secretion systems along with uncharacterized components into a new type of protein translocation apparatus. A representative of the Tad apparatus, the Caulobacter crescentus pilus assembly (Cpa) machine is built exclusively at the newborn cell pole once per cell cycle. Recent comprehensive genetic analyses unearthed a myriad of spatiotemporal determinants acting on the Tad/Cpa system, many of which are conserved in other α-proteobacteria, including obligate intracellular pathogens and symbionts.
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17
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Shanmugam M, Oyeniyi AO, Parthiban C, Gujjarlapudi SK, Pier GB, Ramasubbu N. Role of de-N-acetylase PgaB from Aggregatibacter actinomycetemcomitans in exopolysaccharide export in biofilm mode of growth. Mol Oral Microbiol 2017; 32:500-510. [PMID: 28548373 DOI: 10.1111/omi.12188] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2017] [Indexed: 11/29/2022]
Abstract
Aggregatibacter actinomycetemcomitans, a Gram-negative bacterium, is the causative agent of localized aggressive periodontitis. Attachment to a biotic surface is a critical first step in the A. actinomycetemcomitans infection process for which exopolysaccharides have been shown to be essential. In addition, the pga operon, containing genes encoding for biosynthetic proteins for poly-N-acetyl glucosamine (PNAG), plays a key role in A. actinomycetemcomitans virulence, as a mutant strain lacking the pga operon induces significantly less bone resorption. Among the genes in the pga operon, pgaB codes for a de-N-acetylase that is responsible for the deacetylation of the PNAG exopolysaccharide. Here we report the role of PgaB in regulation of virulence genes using a markerless, scarless deletion mutant targeting the coding region of the N-terminal catalytic domain of PgaB. The results demonstrate that the N-terminal, catalytic domain of PgaB is crucial for exopolysaccharide export.
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Affiliation(s)
- M Shanmugam
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, USA
| | - A O Oyeniyi
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, USA
| | - C Parthiban
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, USA
| | - S K Gujjarlapudi
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, USA
| | - G B Pier
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - N Ramasubbu
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, USA
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18
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Cheng Q, Wu L, Tu R, Wu J, Kang W, Su T, Du R, Liu W. Mycoplasma fermentans deacetylase promotes mammalian cell stress tolerance. Microbiol Res 2017; 201:1-11. [PMID: 28602396 DOI: 10.1016/j.micres.2017.04.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Revised: 04/09/2017] [Accepted: 04/22/2017] [Indexed: 12/19/2022]
Abstract
Mycoplasma fermentans is a pathogenic bacterium that infects humans and has potential pathogenic roles in respiratory, genital and rheumatoid diseases. NAD+-dependent deacetylase is involved in a wide range of pathophysiological processes and our studies have demonstrated that expression of mycoplasmal deacetylase in mammalian cells inhibits proliferation but promotes anti-starvation stress tolerance. Furthermore, mycoplasmal deacetylase is involved in cellular anti-oxidation, which correlates with changes in the proapoptotic proteins BIK, p21 and BIM. Mycoplasmal deacetylase binds to and deacetylates the FOXO3 protein, similar with mammalian SIRT2, and affects expression of the FOXO3 target gene BIM, resulting in inhibition of cell proliferation. Mycoplasmal deacetylase also alters the performance of cells under drug stress. This study expands our understanding of the potential molecular and cellular mechanisms of interaction between mycoplasmas and mammalian cells.
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Affiliation(s)
- Qingzhou Cheng
- College of Health Sciences and Nursing, Wuhan Polytechnic University, Wuhan, Hubei, China
| | - Lijuan Wu
- College of Health Sciences and Nursing, Wuhan Polytechnic University, Wuhan, Hubei, China
| | - Rongfu Tu
- College of Life Sciences, Wuhan University, Wuhan, Hubei, China
| | - Jun Wu
- College of Health Sciences and Nursing, Wuhan Polytechnic University, Wuhan, Hubei, China
| | - Wenqian Kang
- College of Life Sciences, Wuhan University, Wuhan, Hubei, China
| | - Tong Su
- College of Life Sciences, Wuhan University, Wuhan, Hubei, China
| | - Runlei Du
- College of Life Sciences, Wuhan University, Wuhan, Hubei, China.
| | - Wenbin Liu
- College of Health Sciences and Nursing, Wuhan Polytechnic University, Wuhan, Hubei, China; College of Medicine, University of Florida, Gainesville, FL, USA.
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19
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Cohesive Properties of the Caulobacter crescentus Holdfast Adhesin Are Regulated by a Novel c-di-GMP Effector Protein. mBio 2017; 8:mBio.00294-17. [PMID: 28325767 PMCID: PMC5362036 DOI: 10.1128/mbio.00294-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
When encountering surfaces, many bacteria produce adhesins to facilitate their initial attachment and to irreversibly glue themselves to the solid substrate. A central molecule regulating the processes of this motile-sessile transition is the second messenger c-di-GMP, which stimulates the production of a variety of exopolysaccharide adhesins in different bacterial model organisms. In Caulobacter crescentus, c-di-GMP regulates the synthesis of the polar holdfast adhesin during the cell cycle, yet the molecular and cellular details of this control are currently unknown. Here we identify HfsK, a member of a versatile N-acetyltransferase family, as a novel c-di-GMP effector involved in holdfast biogenesis. Cells lacking HfsK form highly malleable holdfast structures with reduced adhesive strength that cannot support surface colonization. We present indirect evidence that HfsK modifies the polysaccharide component of holdfast to buttress its cohesive properties. HfsK is a soluble protein but associates with the cell membrane during most of the cell cycle. Coincident with peak c-di-GMP levels during the C. crescentus cell cycle, HfsK relocalizes to the cytosol in a c-di-GMP-dependent manner. Our results indicate that this c-di-GMP-mediated dynamic positioning controls HfsK activity, leading to its inactivation at high c-di-GMP levels. A short C-terminal extension is essential for the membrane association, c-di-GMP binding, and activity of HfsK. We propose a model in which c-di-GMP binding leads to the dispersal and inactivation of HfsK as part of holdfast biogenesis progression. Exopolysaccharide (EPS) adhesins are important determinants of bacterial surface colonization and biofilm formation. Biofilms are a major cause of chronic infections and are responsible for biofouling on water-exposed surfaces. To tackle these problems, it is essential to dissect the processes leading to surface colonization at the molecular and cellular levels. Here we describe a novel c-di-GMP effector, HfsK, that contributes to the cohesive properties and stability of the holdfast adhesin in C. crescentus. We demonstrate for the first time that c-di-GMP, in addition to its role in the regulation of the rate of EPS production, also modulates the physicochemical properties of bacterial adhesins. By demonstrating how c-di-GMP coordinates the activity and subcellular localization of HfsK, we provide a novel understanding of the cellular processes involved in adhesin biogenesis control. Homologs of HfsK are found in representatives of different bacterial phyla, suggesting that they play important roles in various EPS synthesis systems.
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20
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A Rhizobiales-Specific Unipolar Polysaccharide Adhesin Contributes to Rhodopseudomonas palustris Biofilm Formation across Diverse Photoheterotrophic Conditions. Appl Environ Microbiol 2017; 83:AEM.03035-16. [PMID: 27986718 DOI: 10.1128/aem.03035-16] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 12/08/2016] [Indexed: 12/25/2022] Open
Abstract
Bacteria predominantly exist as members of surfaced-attached communities known as biofilms. Many bacterial species initiate biofilms and adhere to each other using cell surface adhesins. This is the case for numerous ecologically diverse Alphaprotebacteria, which use polar exopolysaccharide adhesins for cell-cell adhesion and surface attachment. Here, we show that Rhodopseudomonas palustris, a metabolically versatile member of the alphaproteobacterial order Rhizobiales, contains a functional unipolar polysaccharide (UPP) biosynthesis gene cluster. Deletion of genes predicted to be critical for UPP biosynthesis and export abolished UPP production. We also found that R. palustris uses UPP to mediate biofilm formation across diverse photoheterotrophic growth conditions, wherein light and organic substrates are used to support growth. However, UPP was less important for biofilm formation during photoautotrophy, where light and CO2 support growth, and during aerobic respiration with organic compounds. Expanding our analysis beyond R. palustris, we examined the phylogenetic distribution and genomic organization of UPP gene clusters among Rhizobiales species that inhabit diverse niches. Our analysis suggests that UPP is a conserved ancestral trait of the Rhizobiales but that it has been independently lost multiple times during the evolution of this clade, twice coinciding with adaptation to intracellular lifestyles within animal hosts. IMPORTANCE Bacteria are ubiquitously found as surface-attached communities and cellular aggregates in nature. Here, we address how bacterial adhesion is coordinated in response to diverse environments using two complementary approaches. First, we examined how Rhodopseudomonas palustris, one of the most metabolically versatile organisms ever described, varies its adhesion to surfaces in response to different environmental conditions. We identified critical genes for the production of a unipolar polysaccharide (UPP) and showed that UPP is important for adhesion when light and organic substrates are used for growth. Looking beyond R. palustris, we performed the most comprehensive survey to date on the conservation of UPP biosynthesis genes among a group of closely related bacteria that occupy diverse niches. Our findings suggest that UPP is important for free-living and plant-associated lifestyles but dispensable for animal pathogens. Additionally, we propose guidelines for classifying the adhesins produced by various Alphaprotebacteria, facilitating future functional and comparative studies.
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21
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Nyarko A, Barton H, Dhinojwala A. Scaling down for a broader understanding of underwater adhesives - a case for the Caulobacter crescentus holdfast. SOFT MATTER 2016; 12:9132-9141. [PMID: 27812588 DOI: 10.1039/c6sm02163h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The adhesion of two materials in the presence of water is greatly impeded by a boundary layer of water between the adhesive and the adherend, resulting in adhesive failure of most synthetic adhesives; however, life evolved first in water and there are many aquatic organisms that have to overcome this impediment to underwater adhesion. For example, multicellular aquatic organisms like the mussel, sandcastle worm and the caddisfly larva employ well-studied adhesive mechanisms for sticking in the presence of water. Unicellular organisms such as bacteria also make use of various means for attaching to surfaces, within similar environmental conditions. Prominent among them is the aquatic bacteria, Caulobacter crescentus which utilizes a unique adhesive secretion, the holdfast, to adhere strongly in the presence of water. Here we review the attachment mechanisms of some multicellular aquatic organisms and compare the similarities and differences in the composition and structure of the C. crescentus holdfast, which holds promise as a potential source for bio-inspired synthetic underwater adhesives with prospective applications in medicine, engineering and biomimetics.
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Affiliation(s)
- Alex Nyarko
- Department of Polymer Science, The University of Akron, Akron, OH 44325-3909, USA.
| | - Hazel Barton
- Department of Biology, The University of Akron, Akron, OH 44325-3908, USA
| | - Ali Dhinojwala
- Department of Polymer Science, The University of Akron, Akron, OH 44325-3909, USA.
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22
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Abstract
During the first step of biofilm formation, initial attachment is dictated by physicochemical and electrostatic interactions between the surface and the bacterial envelope. Depending on the nature of these interactions, attachment can be transient or permanent. To achieve irreversible attachment, bacterial cells have developed a series of surface adhesins promoting specific or nonspecific adhesion under various environmental conditions. This article reviews the recent advances in our understanding of the secretion, assembly, and regulation of the bacterial adhesins during biofilm formation, with a particular emphasis on the fimbrial, nonfimbrial, and discrete polysaccharide adhesins in Gram-negative bacteria.
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23
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Wang Y, Andole Pannuri A, Ni D, Zhou H, Cao X, Lu X, Romeo T, Huang Y. Structural Basis for Translocation of a Biofilm-supporting Exopolysaccharide across the Bacterial Outer Membrane. J Biol Chem 2016; 291:10046-57. [PMID: 26957546 DOI: 10.1074/jbc.m115.711762] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Indexed: 12/14/2022] Open
Abstract
The partially de-N-acetylated poly-β-1,6-N-acetyl-d-glucosamine (dPNAG) polymer serves as an intercellular biofilm adhesin that plays an essential role for the development and maintenance of integrity of biofilms of diverse bacterial species. Translocation of dPNAG across the bacterial outer membrane is mediated by a tetratricopeptide repeat-containing outer membrane protein, PgaA. To understand the molecular basis of dPNAG translocation, we determined the crystal structure of the C-terminal transmembrane domain of PgaA (residues 513-807). The structure reveals that PgaA forms a 16-strand transmembrane β-barrel, closed by four loops on the extracellular surface. Half of the interior surface of the barrel that lies parallel to the translocation pathway is electronegative, suggesting that the corresponding negatively charged residues may assist the secretion of the positively charged dPNAG polymer. In vivo complementation assays in a pgaA deletion bacterial strain showed that a cluster of negatively charged residues proximal to the periplasm is necessary for biofilm formation. Biochemical analyses further revealed that the tetratricopeptide repeat domain of PgaA binds directly to the N-deacetylase PgaB and is critical for biofilm formation. Our studies support a model in which the positively charged PgaB-bound dPNAG polymer is delivered to PgaA through the PgaA-PgaB interaction and is further targeted to the β-barrel lumen of PgaA potentially via a charge complementarity mechanism, thus priming the translocation of dPNAG across the bacterial outer membrane.
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Affiliation(s)
- Yan Wang
- From the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Archana Andole Pannuri
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida 32611-0700
| | - Dongchun Ni
- Department of Cardiovascular Diseases, Tianjin Xiqing Hospital, Tianjin 300380, China
| | - Haizhen Zhou
- From the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiou Cao
- School of Life Sciences, Peking University, Beijing 100871, China, and
| | - Xiaomei Lu
- Dongguan Institute of Pediatrics, the Eighth People's Hospital of Dongguan, Dongguan 523325, Guangdong Province, China
| | - Tony Romeo
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida 32611-0700,
| | - Yihua Huang
- From the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China,
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24
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Baker P, Ricer T, Moynihan PJ, Kitova EN, Walvoort MTC, Little DJ, Whitney JC, Dawson K, Weadge JT, Robinson H, Ohman DE, Codée JDC, Klassen JS, Clarke AJ, Howell PL. P. aeruginosa SGNH hydrolase-like proteins AlgJ and AlgX have similar topology but separate and distinct roles in alginate acetylation. PLoS Pathog 2014; 10:e1004334. [PMID: 25165982 PMCID: PMC4148444 DOI: 10.1371/journal.ppat.1004334] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2014] [Accepted: 07/08/2014] [Indexed: 02/05/2023] Open
Abstract
The O-acetylation of polysaccharides is a common modification used by pathogenic organisms to protect against external forces. Pseudomonas aeruginosa secretes the anionic, O-acetylated exopolysaccharide alginate during chronic infection in the lungs of cystic fibrosis patients to form the major constituent of a protective biofilm matrix. Four proteins have been implicated in the O-acetylation of alginate, AlgIJF and AlgX. To probe the biological function of AlgJ, we determined its structure to 1.83 Å resolution. AlgJ is a SGNH hydrolase-like protein, which while structurally similar to the N-terminal domain of AlgX exhibits a distinctly different electrostatic surface potential. Consistent with other SGNH hydrolases, we identified a conserved catalytic triad composed of D190, H192 and S288 and demonstrated that AlgJ exhibits acetylesterase activity in vitro. Residues in the AlgJ signature motifs were found to form an extensive network of interactions that are critical for O-acetylation of alginate in vivo. Using two different electrospray ionization mass spectrometry (ESI-MS) assays we compared the abilities of AlgJ and AlgX to bind and acetylate alginate. Binding studies using defined length polymannuronic acid revealed that AlgJ exhibits either weak or no detectable polymer binding while AlgX binds polymannuronic acid specifically in a length-dependent manner. Additionally, AlgX was capable of utilizing the surrogate acetyl-donor 4-nitrophenyl acetate to catalyze the O-acetylation of polymannuronic acid. Our results, combined with previously published in vivo data, suggest that the annotated O-acetyltransferases AlgJ and AlgX have separate and distinct roles in O-acetylation. Our refined model for alginate acetylation places AlgX as the terminal acetlytransferase and provides a rationale for the variability in the number of proteins required for polysaccharide O-acetylation. Bacteria utilize many defense strategies to protect themselves against external forces. One mechanism used by the bacterium Pseudomonas aeruginosa is the production of the long sugar polymer alginate. The bacteria use this polymer to form a biofilm – a barrier to protect against antibiotics and the host immune response. During its biosynthesis alginate undergoes a chemical modification whereby acetate is added to the polymer. Acetylation of alginate is important as this modification makes the bacterial biofilm less susceptible to recognition and clearance by the host immune system. In this paper we present the atomic structure of AlgJ; one of four proteins required for O-acetylation of the polymer. AlgJ is structurally similar to AlgX, which we have shown previously is also required for alginate acetylation. To understand why both enzymes are required for O-acetylation we functionally characterized the proteins and found that although AlgJ exhibits acetylesterase activity – catalyzing the removal of acetyl groups from a surrogate substrate – it does not bind to short mannuornic acid polymers. In contrast, AlgX bound alginate in a length-dependent manner and was capable of transfering acetate from a surrogate substrate onto alginate. This has allowed us to not only understand how acetate is added to alginate, but increases our understanding of how acetate is added to other bacterial sugar polymers.
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Affiliation(s)
- Perrin Baker
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Tyler Ricer
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Patrick J. Moynihan
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Elena N. Kitova
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | | | - Dustin J. Little
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - John C. Whitney
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Karen Dawson
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Joel T. Weadge
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Howard Robinson
- Photon Sciences Division, Brookhaven National Laboratory, Upton, New York, United States of America
| | - Dennis E. Ohman
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center and McGuire Veterans Affairs Medical Center, Richmond, Virginia, United States of America
| | - Jeroen D. C. Codée
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - John S. Klassen
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Anthony J. Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - P. Lynne Howell
- Program in Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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25
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Sequential evolution of bacterial morphology by co-option of a developmental regulator. Nature 2014; 506:489-93. [PMID: 24463524 PMCID: PMC4035126 DOI: 10.1038/nature12900] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 11/20/2013] [Indexed: 01/03/2023]
Abstract
What mechanisms underlie the transitions responsible for the diverse shapes observed in the living world? While bacteria display a myriad of morphologies1, the mechanisms responsible for the evolution of bacterial cell shape are not understood. We investigated morphological diversity in a group of bacteria that synthesize an appendage-like extension of the cell envelope called the stalk2,3. The location and number of stalks varies among species, as exemplified by three distinct sub-cellular positions of stalks within a rod-shaped cell body: polar in the Caulobacter genus, and sub-polar or bi-lateral in the Asticcacaulis genus4. Here we show that a developmental regulator of Caulobacter crescentus, SpmX5, was co-opted in the Asticcacaulis genus to specify stalk synthesis at either the sub-polar or bi-lateral positions. We show that stepwise evolution of a specific region of SpmX led to the gain of a new function and localization of this protein, which drove the sequential transition in stalk positioning. Our results indicate that evolution of protein function, co-option, and modularity are key elements in the evolution of bacterial morphology. Therefore, similar evolutionary principles of morphological transitions apply to both single-celled prokaryotes and multicellular eukaryotes.
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Draft Genome Sequence of the Dimorphic Prosthecate Bacterium Brevundimonas abyssalis TAR-001T. GENOME ANNOUNCEMENTS 2013; 1:1/5/e00826-13. [PMID: 24136847 PMCID: PMC3798453 DOI: 10.1128/genomea.00826-13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the 3.0-Mb draft genome sequence of Brevundimonas abyssalis strain TAR-001T, isolated from deep-sea floor sediment. The draft genome sequence of strain TAR-001T consists of 2,979,700 bp in 128 contigs, with a G+C content of 68.2%, 2,946 potential coding sequences (CDS), 3 rRNAs, and 41 tRNAs.
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27
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Berne C, Ma X, Licata NA, Neves BRA, Setayeshgar S, Brun YV, Dragnea B. Physiochemical properties of Caulobacter crescentus holdfast: a localized bacterial adhesive. J Phys Chem B 2013; 117:10492-503. [PMID: 23924278 DOI: 10.1021/jp405802e] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
To colonize surfaces, the bacterium Caulobacter crescentus employs a polar polysaccharide, the holdfast, located at the end of a thin, long stalk protruding from the cell body. Unlike many other bacteria which adhere through an extended extracellular polymeric network, the holdfast footprint area is tens of thousands times smaller than that of the total bacterium cross-sectional surface, making for some very demanding adhesion requirements. At present, the mechanism of holdfast adhesion remains poorly understood. We explore it here along three lines of investigation: (a) the impact of environmental conditions on holdfast binding affinity, (b) adhesion kinetics by dynamic force spectroscopy, and (c) kinetic modeling of the attachment process to interpret the observed time-dependence of the adhesion force at short and long time scales. A picture emerged in which discrete molecular units called adhesins are responsible for initial holdfast adhesion, by acting in a cooperative manner.
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Affiliation(s)
- Cécile Berne
- Department of Biology, Indiana University , Bloomington, Indiana 47405, United States
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