期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1979
卷号：76
期号：11
页码：5952-5956
DOI：10.1073/pnas.76.11.5952
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Myxococcus xanthus, an organism whose motility involves cell interactions, normally bears pili. Myxococcal pili are found only at cell poles, are less than 10 nm in diameter, and may be longer than a cell. Myxococcus has two basic patterns of cell movement, adventurous (A-motility) and social (S-motility). Pili are found to be completely correlated with the presence of S-motility. (The S-motility pattern has many groups of cells, almost no single cells, and is governed by a set of genes called system S.) On the other hand, A-motility is in dependent of piliation. (The A-motility pattern has many single, isolated cells and it is governed by a second set of genes called system A.) Electron microscopic examination of more than 40 genetically different strains shows that all A+S+ (wild-type) and A-S+ strains have pili, but A+S- and A-S- strains lack them. Mutations in four different loci belonging to system S were tested and were found to stop productions of pili: the loci sg1A, sg1B, sg1G, and tg1. When brought into contact with tg1+ cells, cells of a tg1- strain, which lack pili, become phenotypically S+, produce pili, and become S-motile. Both motility and the production of pili are transient when initiated in this way. Thus it appears that pili permit cells that are close to one another to move.
