Gliding motility and polarized slime secretion

Abstract

SummaryMyxococcus leaves a trail of slime on agar as it moves. A filament of slime can be seen attached to the end of a cell, but it is seen only at one end at any particular moment. To identify genes essential for A motility, transposon insertion mutations with defective A motility were studied. Fifteen of the 33 mutants had totally lost A motility. All these mutant cells had filaments of slime emerging from both ends, indicating that bipolar secretion prevents A motility. The remaining 18 A motility mutants, also produced by gene knockout, secreted slime only from one pole, but they swarmed at a lower rate than A + and are called 'partial' gliding mutants, or pgl. For each pgl mutant, the reduction in swarm expansion rate was directly proportional to the reduction in the coefficient of elasticotaxis. The pgl mutants have a normal reversal frequency and normal gliding speed when they move. But their probability of movement per unit time is lower than pgl + cells. Many of the pgl mutants are produced by transposon insertions in glycosyltransferase genes. It is proposed that these glycosyltransferases carry out the synthesis of a repeat unit polysaccharide that constitutes the slime.

Gliding Motility Revisited: How Do the Myxobacteria Move without Flagella?

“…2), indicating the presence of an additional motility system which they called A motility (41). Extensive genetic screens, especially by the Hartzell and Kaiser laboratories, have identified numerous genes involved in A motility (143,144,146). Specifically, over 35 genes were identified as being involved in A motility, although none of these genes encoded obvious motility structures or machinery (143).…”

Macroscopic model of self-propelled bacteria swarming with regular reversals

“…To test that the diffusion curves in Figure 6b actually predict the diffusion in the stochastic model, we compared numerical solutions of the diffusion equation (1) with D(p) derived using BM analysis of MSM simulations with different reversal periods at an early and a later times (see Figure 7). Very good match is demonstrated for p > p 0 , where the critical density p 0 is defined in (4).…”

“…These bacteria have elongated rod-type shapes (about 7µm in length and 0.5µm in width) and they move by gliding over a substrate in the direction of their longer axis [1,2,4,5]. They align and travel together in the same direction (see Figure 1a) as well as reverse direction of their motion about every eight minutes [1,5,6].…”

Hdsp, a horizontally transferred gene required for social behavior and halotolerance in salt-tolerant Myxococcus fulvus HW-1

“…Proteins that contain TPRs are normally involved in a variety of biological processes, such as cell cycle regulation, transcriptional control, mitochondrial and peroxisomal protein transport, neurogenesis and protein folding (Blatch and Lässle, 1999). Proteins containing TPR were also reported to be involved in motility and fruiting body formation in DK1622 (Youderian et al, 2003;Nariya and Inouye, 2005;Yu and Kaiser, 2007;Scott et al, 2008). It is therefore possible that the putative TPR motifs in Hdsp also have a role in mediating interactions between Hdsp and other proteins.…”