The function of fimbriae in Myxococcus xanthus. I. Purification and properties of M. xanthus fimbriae

Dobson, William J.; McCurdy, Howard D.

doi:10.1139/m79-179

Cited by 21 publications

(14 citation statements)

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“…The thin fibrils, about 5 nm wide, which were found on both wild-type and Dsp cells correspond in size to pili (also called fimbriae) which have previously been observed on myxobacteria (6,15,19). The strong correlation between pili and S motility observed by Kaiser (15) suggests a function in cohesion, because the role of pili as attachment organelles has been demonstrated in a variety of pathogenic bacteria (2,9,17,21,23).…”

Section: Discussionsupporting

confidence: 59%

Cell surface properties correlated with cohesion in Myxococcus xanthus

1988

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The gliding behavior of Myxococcus xanthus cells is controlled by two multigene systems, A and S, which encode information for adventurous and social behaviors, respectively. The S system can be genetically disrupted through mutation, such as a dsp mutation, or phenotypically disrupted by treating cells with the diazo dye Congo red (Arnold and Shimkets, J. Bacteriol. 170:5765-5770, 1988). One of the functions controlled by the S system is cell agglutination. Immediately after the induction of agglutination, wild-type cells begin to form aggregates, and within 30 min the cells are packed side-to-side in clumps containing thousands of cells. Changes in the cohesive properties of S+ cells are correlated with changes in the topology of the cell surface observed by electron microscopy. Two types of cell-associated appendages were observed on wild-type cells: thin filaments (ca. 5 nm in diameter), which have been called fimbriae or pili, at one cell pole, and thick, flaccid ifiaments (ca. 50 nm in diameter), referred to as fibrils, at both the sides and tips of cells. Cohesion was correlated with the secretion of the thick fibrils, which coat the cell surface and form an extracellular matrix in which the cells are interconnected. Several lines of evidence suggest that these thick fibrils are involved in cohesion. First, Dsp cells were unable to agglutinate or secrete this extracellular material. Second, wild-type cells which were treated with Congo red neither agglutinated nor secreted the extracellular fibrils. Finally, removal of the Congo red from wild-type cells restored cohesion and also restored production of the thick fibrils. Attempts to estimate the efficiency with which two cells cohered following collision suggested that under optimal conditions, one in three collisions resulted in stable contact. The collision efficiency decreased linearly as the cell density increased, suggesting a cell density-dependent regulation of cohesion. Some aspects of gliding behavior can be explained in terms of an inducer and an inhibitor of S motility.

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Section: Discussionsupporting

confidence: 59%

Cell surface properties correlated with cohesion in Myxococcus xanthus

1988

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“…hydrophila are composed of a biochemically unique pilin polypeptide. Flexible pilin is 4 kD, by far the smallest pilus subunit reported to date, even when compared with the 8-kD pilin of Myxococcus xanthus (27) . Moreover, its primary structure is entirely novel.…”

Section: Discussionmentioning

confidence: 90%

The pili of Aeromonas hydrophila: identification of an environmentally regulated "mini pilin".

Mietzner

Smith

et al. 1990

The Journal of Experimental Medicine

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SummaryUltrastructural studies ofAeromonas hydrophila strain AH26 revealed two distinctive pilus types: "straight" pili appear as brittle, rod-like filaments, whereas "flexible" pili are supple and curvilinear. Straight pili are produced constitutively under all tested conditions of growth. In contrast, the expression of flexible pili is regulated by physical and chemical variables, being produced at 22 vs. 37°C, in a liquid vs. a solid medium, and when the availability of free-iron is reduced by the presence of deferoxamine mesylate. Both pilus proteins were purified and biochemically and functionally characterized. The major repeating subunit of the straight pilus is a 17,000-mol wt polypeptide with amino acid sequence homology with Escherichia coli type 1 and Pap pili. The flexible pilus filament is a homopolymer composed of a novel 46 amino acid polypeptide. Resistance of the flexible pilus filament to disaggregation using various chemical treatments was demonstrated; its stability as a polymer and its apparent mechanical strength seem to be conferred by a 20 amino acid hydrophobic, COOH-terminal domain. Purified straight pili lack hemagglutinating function. In contrast, purified flexible pili cause the agglutinin of human, guinea pig, ovine, bovine, and avian erythrocytes, although this property could only be demonstrated in the presence of divalent cations and was most evident at 4 vs. 22°C. Taken together, these results suggest that the pathogenic and ecological roles of the flexible pilus are related to this species' existence as a free-living organism in aquatic environments and its ability to cause infections, both in cold-blooded vertebrates and the human intestine.

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“…While pili (fimbriae) have been shown to mediate some of these contact-mediated interactions (7,26), it is now beginning to appear that the extracellular fibrils of M. xanthus may also play a role in these interactions (1,2,52,53). The specificity of these interactions during development may be determined by fibrillar proteins such as dFA-1.…”

Section: Discussionmentioning

confidence: 99%

A development-specific protein in Myxococcus xanthus is associated with the extracellular fibrils

1991

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We have been using monoclonal antibodies (MAbs) as probes to study developmentally relevant cell surface antigens (CSA) that may be required for cellular interactions in Myxococcus xanthus. Three independently isolated MAbs, G69, G357, and G645, isolated by Gill and Dworkin recognize a CSA detectable only on developing cells (J. S. Gill and M. Dworkin, J. Bacteriol. 168:505-511, 1986). The CSA is made within the first 30 min of submerged development and increases until myxosporulation. The CSA is also produced at low levels after 24 h in shaken-starved cultures and during glycerol sporulation. No antigen can be detected in lysed, vegetative cells, and expression of the antigen is blocked in the presence of rifampin or chloramphenicol. The antigen is expressed in submerged, developmental cultures of asg, bsg, csg, dsg, and mgl mutants and is not expressed in a dsp mutant. All of the three MAbs immunoprecipitate the same protein of approximately 97,000 Da from lysed developmental cells. Competitive immunoprecipitations suggest that they recognize at least two different epitopes on the CSA. The epitopes recognized by MAbs G69, G357, and G645 are sensitive to protease digestion, whereas the epitopes recognized by MAbs G357 and G645 are resistant to periodate oxidation. The epitope recognized by MAb G69 is sensitive to periodate oxidation. Fractionation of lysed developing cells shows that most of the antigen is localized in the pellet after centrifugation at 100,000 x g. To determine whether the antigen is expressed on the cell surface, we labeled developing whole cells with either MAb G69, G357, or G645 and gold-labeled anti-mouse immunoglobulin G. Low-voltage scanning electron microscopy of labeled cells shows that the antigen is associated with the fibrillar matrix that surrounds the cells and that the antigen is retained on isolated, developmental fibrils from M. xanthus. The CSA has been designated dFA-1, for developmental fibrillar antigen 1.

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The function of fimbriae in Myxococcus xanthus. I. Purification and properties of M. xanthus fimbriae

Cited by 21 publications

References 0 publications

Cell surface properties correlated with cohesion in Myxococcus xanthus

Cell surface properties correlated with cohesion in Myxococcus xanthus

The pili of Aeromonas hydrophila: identification of an environmentally regulated "mini pilin".

A development-specific protein in Myxococcus xanthus is associated with the extracellular fibrils

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