Cell surface properties correlated with cohesion in Myxococcus xanthus

• Published in: Journal of Bacteriology Vol. 170; no. 12; pp. 5771 - 5777
• Main Authors: Arnold, J.W, Shimkets, L.J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01.12.1988
• Subjects: BACTERIA; BACTERIE; Bacteriology; Biological and medical sciences; Cell Communication; Cell Membrane - ultrastructure; CELLULE; CELULAS; Congo Red - pharmacology; CONTROL GENETICO; FLORA DEL SUELO; FLORE DU SOL; Fundamental and applied biological sciences. Psychology; LUTTE GENETIQUE; Microbiology; Microscopy, Electron; Microscopy, Electron, Scanning; Motility, taxis; Myxococcales - drug effects; Myxococcales - physiology; Myxococcales - ultrastructure; Myxococcus xanthus; REACCIONES DE AGLUTINACION; REACTION D'AGGLUTINATION; SECRECION; SECRETION; Myxococcales; Myxococcus xanthus; Bacteria; Colony swarming; Myxococcaceae; Agglutination; Electron microscopy; Cell surface
• ISSN: 0021-9193; 1098-5530; 1067-8832
• DOI: 10.1128/jb.170.12.5771-5777.1988

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 filaments (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 regualtion of cohesion.