Homology among nearly all plasmids infecting three Bacillus species.
Homology among nearly all plasmids infecting three Bacillus species.
复制标题
感染三种芽孢杆菌属物种的几乎所有质粒之间具有同源性。
DOI：
10.1128/jb.178.1.191-198.1996
复制
发表时间：
1996
影响因子：
3.2
通讯作者：
Cohan,FM
中科院分区：
文献类型：
--
作者：
Zawadzki,P;Riley,MA;Cohan,FM
我们调查了枯草芽孢杆菌菌株和密切相关的菌种B中天然存在的质粒。mojavensis和B.地衣形的以前的研究没有发现这些物种的质粒的宿主受益功能，这表明这些质粒是非互惠的。结果表明，在各菌株中只发现了一种质粒，这表明大多数感染这些芽孢杆菌的质粒属于同一不亲和群。来自这些物种的18个质粒的样品大小从6.9到16 kb不等，除了6个质粒外，所有质粒都分为三个大小组。这些群体的寄主范围和地理范围的大小不同。来自这三种宿主物种的18个质粒中，除1个外，其余均彼此同源。来自这三个物种的隐蔽质粒远不如已知有益于其细菌宿主的质粒（来自其他物种）多样。这些隐蔽质粒之间的低水平的多样性是一致的假设，宿主受益的适应发挥了重要作用，促进质粒种群的共存，但低水平的质粒多样性的其他解释是可能的。质粒与其宿主质粒的同源性的比较表明，芽孢杆菌质粒在自然界中以类似于大肠杆菌的大肠杆菌素质粒的低速率水平转移。
We have surveyed naturally occurring plasmids in strains of Bacillus subtilis and the closely related species B. mojavensis and B. licheniformis. Previous studies have failed to find host-benefitting functions for plasmids of these species, suggesting that these plasmids are nonmutualistic. Only one type of plasmid was found in each plasmid-bearing strain, suggesting that most of the plasmids infecting these Bacillus species are in the same incompatibility group. A sample of 18 plasmids from these species ranged in size from 6.9 to 16 kb, with all but 6 plasmids falling into three size groups. These groups differed in the sizes of their host ranges and geographical ranges. All but 1 of the 18 plasmids from these three host species are homologous with one another. The cryptic plasmids from these three species are far less diverse than are plasmids (from other species) that are known to benefit their bacterial hosts. The low-level diversity among these cryptic plasmids is consistent with the hypothesis that host-benefitting adaptations play an important role in fostering the coexistence of plasmid populations, but other explanations for the low-level plasmid diversity are possible. Comparison of the phylogenies of the plasmids with those of their hosts suggests that Bacillus plasmids are horizontally transferred in nature at a low rate similar to that found for the colicin plasmids of Escherichia coli.