Regulated ploidy of Bacillus subtilis and three new isolates of Bacillus and Paenibacillus
Regulated ploidy of Bacillus subtilis and three new isolates of Bacillus and Paenibacillus
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DOI：
10.1093/femsle/fnx282
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发表时间：
2018-02-01
影响因子：
2.1
通讯作者：
Soppa, Joerg
中科院分区：
文献类型：
--
作者：
Boettinger, Benjamin;Semmler, Florian;Soppa, Joerg
长期以来，细菌一直被认为是单倍体，维持着一个环形染色体的副本。近年来，在原核生物的几个系统发育类群中，大多数物种都是寡倍体或多倍体。本研究旨在调查革兰氏阳性需氧内孢子形成菌的倍性。首先，对实验室广泛使用的枯草芽孢杆菌168菌株的起源和终止点进行了量化。该菌株在指数期为亚寡倍体(5.9个起始点，1.2个末端)，并在稳定期下调起始点的数量。在接种了静止相细胞的新鲜培养基后，复制的开始先于质量增加的开始。为了对新鲜菌株进行倍性分析，从土壤中分离到3株细菌，分别属于芽孢杆菌属和拟芽孢杆菌属。三个菌株均为指数期亚寡倍体，在稳定期表现出生长阶段依赖性的倍性下调。综上所述，这些结果表明亚寡倍体以及生长阶段相关的拷贝数调控可能在芽孢杆菌和相关属中广泛存在，并具有代表性。
Bacteria were long assumed to be monoploid, maintaining one copy of a circular chromosome. In recent years it became obvious that the majority of species in several phylogenetic groups of prokaryotes are oligoploid or polyploid. The present study aimed at investigating the ploidy in Gram-positive aerobic endospore-forming bacteria. First, the numbers of origins and termini of the widely used laboratory strain Bacillus subtilis 168 were quantified. The strain was found to be mero-oligoploid in exponential phase (5.9 origins, 1.2 termini) and to down-regulate the number of origins in stationary phase. After inoculation of fresh medium with stationary-phase cells the onset of replication preceded the onset of mass increase. For the analysis of the ploidy in fresh isolates, three strains were isolated from soil, which were found to belong to the genera of Bacillus and Paenibacillus. All three strains were found to be mero-oligoploid in exponential phase and exhibit a growth phase-dependent down-regulation of the ploidy level in stationary phase. Taken together, these results indicate that mero-oligoploidy as well as growth phase-dependent copy number regulation might be widespread in and typical for Bacillus and related genera.