Self-organized and highly ordered domain structures within swarms of Myxococcus xanthus.

Coordinated group movement (swarming) is a key aspect of Myxococcus xanthus' social behavior. Here we report observation of domain structures formed by multiple cells within large three-dimensional swarming groups grown on amorphous glass substrates, using the atomic force microscope (AFM). Novel analyses revealed that 90% of the wild type swarms displayed some form of preferential cell alignment.

Analysing protein-protein interactions of the Myxococcus xanthus Dif signalling pathway using the yeast two-hybrid system.

The dif operon is essential for fruiting body formation, fibril (exopolysaccharide) production and social motility of Myxococcus xanthus. The dif locus contains a gene cluster homologous to chemotaxis genes such as mcp (difA), cheW (difC), cheY (difD), cheA (difE) and cheC (difF), as well as an unknown ORF called difB. This study used yeast two-hybrid analysis to investigate possible interactions between Dif proteins, and determined that DifA, C, D and E interact in a similar fashion to chemotaxis proteins of Escherichia coli and Bacillus subtilis.

Characterization of a Myxococcus xanthus mutant that is defective for adventurous motility and social motility.

Myxococcus xanthus is a gliding bacterium that possesses two motility systems, the adventurous (A-motility) and social (S-motility) systems. A-motility is used for individual cell gliding, while S-motility is used for gliding in multicellular groups. Video microscopy studies showed that nla24 cells are non-motile on agar surfaces, suggesting that the nla24 gene product is absolutely required for both A-motility and S-motility under these assay conditions.