Swimming Motility in the Cyanobacterium Synechococcus: A Genetic and Biochemical Approach

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9418842 Brahamsha Certain unicellular cyanobacteria of the genus Synechococcus exhibit a unique form of prokaryotic motility. Unlike other motile cyanobacteria which move by gliding on surfaces, these motile Synechococcus sp. are capable of swimming in liquids. Moreover, although the swimming behavior of Synechococcus resembles that of flagellated bacteria, numerous ultrastructural studies have so far revealed no organelles of motility and the actual mechanism of swimming remains a mystery. At issue are such fundamental questions as how organisms convert chemical energy into motion. The mechanism of swimming is being addressed at the genetic and biochemical levels. Mutants impaired in motility are being obtained by interposon and chemical mutagenesis. The mutations are being complemented by conjugation of a genomic bank of wild-type Synechococcus into the mutant strains. The genes responsible will be cloned, their nucleotide sequences determined, and their products localized. A protease-sensitive cell-surface component(s) implicated in motility is being purified, and the gene(s) encoding it will be isolated, sequenced and inactivated. To accomplish this Dr. Brahamsha is making use of the following recent developments in her laboratory: 1) an agar plating technique that allows the discrimination between motile and non-motile colonies and will make possible the selection of non-motile mutants; 2) the ability to introduce DNA into marine motile Synechococcus sp. and to get recombination into the chromosome; 3) the availability of both a replicative and a suicide vector; and 4) the indication that there is a protease-sensitive cell-surface component(s) that is involved in the ability to swim in liquids. %%% The results of this research should provide insights into the mechanisms by which organisms convert chemical energy into motion.