Schäfer H, Servais P, Muyzer G
Max-Planck-Institut für Marine Mikrobiologie, Bremen, Germany.
Arch Microbiol. 2000 Feb;173(2):138-45. doi: 10.1007/s002039900121.
The successional changes in the genetic diversity of Mediterranean bacterioplankton subjected to confinement were studied in an experimental 300 1 seawater enclosure. Five samples were taken at different times and analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprinting to rapidly monitor changes in the bacterial genetic diversity. DGGE analysis clearly showed variations between the samples. Three of the five samples, with different DGGE banding patterns, were further analyzed by cloning and sequencing of 16S rRNA genes. Comparative sequence analysis indicated a shift from a mixed bacterial assemblage to a community dominated by bacteria closely affiliated to a single genus, Alteromonas. Sequences obtained at the start of the experiment were affiliated with two alpha-proteobacterial and three gamma-proteobacterial lineages known from other studies of marine picoplankton. One sequence was affiliated with the Verrucomicrobiales. After 161 h of incubation two sequences represented a gamma-proteobacterial lineage also present at 0 h, but the majority of sequences clustered around that of Alteromonas macleodii. After 281 h only the dominant Alteromonas-like bacteria and bacteria distantly related to Legionella were found by cloning and sequencing. Mortality rates of bacteria indicated that grazing was the dominant mortality process when heterotrophic protozoa were abundant. Hence, changes in the genetic diversity of bacteria were partly influenced by the differential mortality of bacterial populations during the course of incubation.
在地中海一个300升的海水实验围隔中，研究了受限制的地中海浮游细菌遗传多样性的演替变化。在不同时间采集了五个样本，并通过聚合酶链反应-变性梯度凝胶电泳（PCR-DGGE）指纹图谱进行分析，以快速监测细菌遗传多样性的变化。DGGE分析清楚地显示了样本之间的差异。对五个样本中具有不同DGGE条带模式的三个样本，进一步通过16S rRNA基因的克隆和测序进行分析。比较序列分析表明，从混合细菌群落转变为以与单属密切相关的细菌为主导的群落，即交替单胞菌属。实验开始时获得的序列与其他海洋微微型浮游生物研究中已知的两个α-变形菌纲和三个γ-变形菌纲谱系相关。一个序列与疣微菌目相关。孵育161小时后，两个序列代表在0小时也存在的γ-变形菌纲谱系，但大多数序列聚集在麦氏交替单胞菌周围。孵育281小时后，通过克隆和测序仅发现了占主导地位的类交替单胞菌和与军团菌关系较远的细菌。细菌死亡率表明，当异养原生动物丰富时，捕食是主要的死亡过程。因此，细菌遗传多样性的变化部分受到孵育过程中细菌种群不同死亡率的影响。
