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

小行星9418842 聚球藻属的某些单细胞蓝细菌表现出一种独特的原核运动形式。 与其他活动的蓝细菌通过在表面上滑动而移动不同，这些活动的聚球藻能够在液体中游泳。 此外，虽然聚球藻的游泳行为类似于有鞭毛的细菌，但迄今为止，许多超微结构研究表明没有运动细胞器，游泳的实际机制仍然是一个谜。 争论的焦点是诸如生物体如何将化学能转化为运动等基本问题。 游泳的机制正在遗传和生物化学水平上得到解决。 通过插入子和化学诱变获得运动性受损的突变体。 这些突变通过将野生型聚球藻的基因组库接合到突变菌株中来补充。 负责的基因将被克隆，它们的核苷酸序列将被确定，它们的产物将被定位。 与运动性有关的蛋白酶敏感的细胞表面成分正在被纯化，编码它的基因将被分离、测序和灭活。 为了实现这一目标，Brahamsha博士正在利用她的实验室最近的以下发展：1）琼脂平板技术，该技术允许区分运动和非运动菌落，并将使选择非运动突变体成为可能; 2）将DNA引入海洋运动聚球藻并重组到染色体中的能力; 3）复制和自杀载体的可用性;和4）存在蛋白酶敏感的细胞表面组分的指示，其涉及在液体中游泳的能力。 这项研究的结果应该能为生物体将化学能转化为运动的机制提供深入的了解。

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.