Correlation of energy-dependent cell cohesion with social motility in Myxococcus xanthus

Abstract

An agglutination assay was used to study cell cohesion in the myxobacterium Myxococcus xanthus. Vegetative cells agglutinated in the presence of the divalent cations Mg2+ and Ca2+. Agglutination was blocked by energy poisons that inhibit electron transport, uncouple oxidative phosphorylation, or inhibit the membrane-bound ATPase. However, energy was not required for the maintenance of cells in the multicellular aggregate. Cyanide, a strong inhibitor of agglutination, did not cause cells to dissociate from the aggregate even when shear forces were applied. While gliding motility was not necessary for agglutination, some gliding mutants exhibited aberrant agglutination that was generally correlated with cell behavior. Cells with an intact social motility system were cohesive and glided in large multicellular swarms. Cells with a mutation in their social motility system were 5- to 10-fold less cohesive and tended to glide as single cells. One group of social motility mutants, known as Dsp, did not agglutinate.

Inorganic polyphosphate in the social life of Myxococcus xanthus : Motility, development, and predation

“…Biogenesis of EPS involves genes eps and eas (35), a DnaK homolog (encoded by sglK) (36), chemotaxis homologues (dif ) genes (37), and some uncharacterized dsp genes. EPS-deficient mutants fail to bind calcofluor white dye (38) and are defective in cellular agglutination, S-motility, and fruiting body formation (25,26), phenotypes similar to those in the PPK1 mutant. Especially notable is that the S-motility of M. xanthus resembles the twitching motility of P. aeruginosa, which also depends on PPK1, mutants of which produce less alginate, a major component of P. aeruginosa EPS (K. Ishige and A.K., unpublished data).…”

“…Motility is important for vegetative growth and development because it helps aggregate cells into fruiting bodies and movement within the body so that a signaling threshold is reached that is adequate for sporulation (20)(21)(22). S-motility requires polarly localized type IV pili (TFP) (23,24), fibril polysaccharides (25)(26)(27), and LPS O-antigen (28). Specific sugar moieties of fibril polysaccharides provide binding targets for the TFP of adjacent cells; when pilus retraction is triggered, the cell is pulled forward (27).…”

Frozen motion of gliding bacteria outlines inherent features of the motility apparatus

“…1b, d). This may represent the morphological counterpart of impaired cell cohesion, which was found to be energy-dependent in myxobacteria (Gilmore & White, 1985 ;Shimkets, 1986).…”

Role of autocide AMI in development of Myxococcus xanthus

“…Release of fluorescent material into the supernatant fluid overlying submerged cultures of M. xanthus strains was determined as described previously (23). Cohesion assays were performed on strains DK1622, DK3260, and ER304 as described by Shiitts (26).…”