9423182 Kaiser The bacterium myxococcus exhibits multicellular gliding movements that are highly coordinated. Coordination spans the range of few to many thousands of cells. While growing, a dozen cells may associate and move as a cohort. In fruiting body development, many thousands of cells move coordinately. The aim of this project is to work out the cellular and molecular basis for movement coordination. Despite the apparent complexity of their movements, myxobacterial cells have the structural, chemical and genetic simplicity of Gram-negative bacteria. Previous work on Myxococcus had distinguished two motility patterns called "adventurous" and "social". This project is seeking to identify many of the genes that control social motility and to learn their biochemical functions. For this purpose, mutants defective in social motility are being isolated. Earlier work had identified pili, long thin hairs that projected from one pole of each cell, as necessary for social motility. This project is investigating the way that pili support social motility, by seeking mutants that assemble normal pili, yet fail to show social motility. Steps in transducing a pilus "signal" might be found in this way. The motors responsible for gliding movement have not yet been uncovered in any of the gliding bacteria. The search for mutants is being structured in a way that should allow mutations which inactivate the gliding engines to be detected, a step toward understanding the mechanism of gliding. %%% Multicellular movements are particularly important in the embryonic development of vertebrates, but little is known about how they are organized or regulated. Myxobacteria offer a realistic way to begin to investigate this general problem. ***
