The Myxococcus xanthuspilT locus is required for social gliding motility although pili are still produced

Wu, Samuel S.; Wu, Jie; Kaiser, Dale

doi:10.1046/j.1365-2958.1997.1791550.x

Cited by 175 publications

(209 citation statements)

References 24 publications

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“…Cellular cohesion is closely correlated with M. xanthus S motility. The cohesion of wild-type M. xanthus strains and S-motility-defective dif mutants (43) was examined using the agglutination assay (41). As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

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Myxococcus xanthus dif Genes Are Required for Biogenesis of Cell Surface Fibrils Essential for Social Gliding Motility

et al. 2000

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Myxococcus xanthus social (S) gliding motility has been previously reported by us to require the chemotaxis homologues encoded by the dif genes. In addition, two cell surface structures, type IV pili and extracellular matrix fibrils, are also critical to M. xanthus S motility. We have demonstrated here that M. xanthus dif genes are required for the biogenesis of fibrils but not for that of type IV pili. Furthermore, the developmental defects of dif mutants can be partially rescued by the addition of isolated fibril materials. Along with the chemotaxis genes of various swarming bacteria and the pilGHIJ genes of the twitching bacterium Pseudomonas aeruginosa, the M. xanthus dif genes belong to a unique class of bacterial chemotaxis genes or homologues implicated in the biogenesis of structures required for bacterial surface locomotion. Genetic studies indicate that the dif genes are linked to the M. xanthus dsp region, a locus known to be crucial for M. xanthus fibril biogenesis and S gliding.

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Section: Resultsmentioning

confidence: 99%

“…The cohesion of M. xanthus cells was initially measured by an agglutination assay developed by Shimkets (29) and later modified by Wu et al (41). Cells were grown and analyzed in CYE medium.…”

Section: Methodsmentioning

confidence: 99%

Myxococcus xanthus dif Genes Are Required for Biogenesis of Cell Surface Fibrils Essential for Social Gliding Motility

et al. 2000

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“…1A). Importantly, we note that both these strains contain a ΔpilA mutation that abolishes the cell-cell clumping or agglutination seen in WT cells (21). When viewed by transmission electron microscopy (TEM), offset cell chains were seen in detail (Fig.…”

Section: Overexpression Of Traab Triggers the Formation Of Cell-cell mentioning

confidence: 90%

Cell rejuvenation and social behaviors promoted by LPS exchange in myxobacteria

Vassallo

Pathak

Cao

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Bacterial cells in their native environments must cope with factors that compromise the integrity of the cell. The mechanisms of coping with damage in a social or multicellular context are poorly understood. Here we investigated how a model social bacterium, Myxococcus xanthus, approaches this problem. We focused on the social behavior of outer membrane exchange (OME), in which cells transiently fuse and exchange their outer membrane (OM) contents. This behavior requires TraA, a homophilic cell surface receptor that identifies kin based on similarities in a polymorphic region, and the TraB cohort protein. As observed by electron microscopy, TraAB overexpression catalyzed a prefusion OM junction between cells. We then showed that damage sustained by the OM of one population was repaired by OME with a healthy population. Specifically, LPS mutants that were defective in motility and sporulation were rescued by OME with healthy donors. In addition, a mutant with a conditional lethal mutation in lpxC, an essential gene required for lipid A biosynthesis, was rescued by Tradependent interactions with a healthy population. Furthermore, lpxC cells with damaged OMs, which were more susceptible to antibiotics, had resistance conferred to them by OME with healthy donors. We also show that OME has beneficial fitness consequences to all cells. Here, in merged populations of damaged and healthy cells, OME catalyzed a dilution of OM damage, increasing developmental sporulation outcomes of the combined population by allowing it to reach a threshold density. We propose that OME is a mechanism that myxobacteria use to overcome cell damage and to transition to a multicellular organism.Myxococcus xanthus | outer membrane | lipopolysaccharide | lpxC | fusion A fundamental question in biology is how cells cope with damage. Microbes occupy diverse habitats fraught with physical, biological, and chemical insults (1, 2). UV radiation, desiccation, predation, extracellular enzymes, antimicrobial compounds, pH, temperature, and osmolarity changes are all stresses to the individual cell. In addition, when cells are in nutrient-poor environments, cell division can be rare, taking days to months to complete (3). In a slow-growing state, cell-surface components that may not be undergoing active repair can accumulate damage through natural aging processes such as oxidation (4, 5) and protein denaturation. Although internal cell stress response pathways are known (6), mechanisms to cope with cell surface damage are less well understood.Although cell damage threatens the fitness of the individual, social organisms have strength in numbers. The strategy of kin selection allows evolutionarily viable cooperation between individuals in a closely related population (7). Communication between individuals and sharing of resources establishes the potential for assistance between individual population members. Social support can be beneficial when the fitness of individuals in a group depends on collaborative behaviors such as prey hunting or the developm...

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“…The agglutination assay described by Wu et al (1997) was used to determine the cellular cohesion of wildtype and mutant strains. Cells in the exponential phase were harvested, washed with aggregation buffer (10 mM MOPS, pH 7.0, 1 mM CaCl 2 and 1 mM MgCl 2 ) and resuspended to approximately 3610 8 c.f.u.…”

Section: Methodsmentioning

confidence: 99%

PhpA, a tyrosine phosphatase of Myxococcus xanthus, is involved in the production of exopolysaccharide

et al. 2012

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Protein-tyrosine phosphorylation plays a significant role in multiple cellular functions in bacteria. Bacterial tyrosine phosphatases catalyse the dephosphorylation of tyrosyl-phosphorylated proteins. Myxococcus xanthus PhpA shares homology with DNA polymerase and histidinol phosphatase family members. Recombinant His-tagged PhpA requires Mn 2+ or Co 2+ for phosphatase activity, and shows strict specificity for phosphorylated tyrosine residues. The k m values of PhpA for p-nitrophenyl phosphate (pNPP) and phosphotyrosine peptide, RRLIEDAEpYAARG, were 803 and 139 mM, respectively. The phosphatase activity of PhpA was inhibited by sodium orthovanadate with a k i of 33 mM. phpA gene expression was observed under both vegetative and developmental conditions, but peaked during late fruiting body formation. A phpA mutant exhibited an elevated level of tyrosine phosphorylation of a 79 kDa protein and cytoplasmic tyrosine kinase, BtkA. In M. xanthus, exopolysaccharide (EPS) is essential for cellcell adhesion and fruiting body formation. phpA mutant cells exhibited enhanced capacity for cellcell agglutination in agglutination buffer. Under starvation conditions, phpA mutation caused early aggregation and sporulation. The EPS production assay showed that the phpA mutant produced an increased amount of EPS in comparison with the wild-type. These results indicate that PhpA may negatively regulate the production of EPS in M. xanthus.

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**The Myxococcus xanthuspilT locus is required for social gliding motility although pili are still produced**

Cited by 175 publications

References 24 publications

Myxococcus xanthus dif Genes Are Required for Biogenesis of Cell Surface Fibrils Essential for Social Gliding Motility

Myxococcus xanthus dif Genes Are Required for Biogenesis of Cell Surface Fibrils Essential for Social Gliding Motility

Cell rejuvenation and social behaviors promoted by LPS exchange in myxobacteria

PhpA, a tyrosine phosphatase of Myxococcus xanthus, is involved in the production of exopolysaccharide

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