Department of Marine Biology and Oceanography, Institut de Ciències del Mar, Consejo Superior de Investigaciones Científicas (CSIC), Barcelona, Spain.
ISME J. 2013 May;7(5):1026-37. doi: 10.1038/ismej.2012.169. Epub 2013 Jan 10.
Bacteroidetes are commonly assumed to be specialized in degrading high molecular weight (HMW) compounds and to have a preference for growth attached to particles, surfaces or algal cells. The first sequenced genomes of marine Bacteroidetes seemed to confirm this assumption. Many more genomes have been sequenced recently. Here, a comparative analysis of marine Bacteroidetes genomes revealed a life strategy different from those of other important phyla of marine bacterioplankton such as Cyanobacteria and Proteobacteria. Bacteroidetes have many adaptations to grow attached to particles, have the capacity to degrade polymers, including a large number of peptidases, glycoside hydrolases (GHs), glycosyl transferases, adhesion proteins, as well as the genes for gliding motility. Several of the polymer degradation genes are located in close association with genes for TonB-dependent receptors and transducers, suggesting an integrated regulation of adhesion and degradation of polymers. This confirmed the role of this abundant group of marine bacteria as degraders of particulate matter. Marine Bacteroidetes had a significantly larger number of proteases than GHs, while non-marine Bacteroidetes had equal numbers of both. Proteorhodopsin containing Bacteroidetes shared two characteristics: small genome size and a higher number of genes involved in CO2 fixation per Mb. The latter may be important in order to survive when floating freely in the illuminated, but nutrient-poor, ocean surface.
拟杆菌门通常被认为专门降解高分子量 (HMW) 化合物，并偏爱附着在颗粒、表面或藻类细胞上生长。最初测序的海洋拟杆菌门基因组似乎证实了这一假设。最近已经测序了更多的基因组。在这里，对海洋拟杆菌门基因组的比较分析揭示了一种与海洋浮游细菌的其他重要门（如蓝细菌和变形菌门）不同的生活策略。拟杆菌门有许多适应附着在颗粒上生长的特性，有降解聚合物的能力，包括大量的肽酶、糖苷水解酶 (GHs)、糖基转移酶、粘附蛋白，以及滑行运动的基因。一些聚合物降解基因与 TonB 依赖性受体和转导蛋白的基因密切相关，这表明对粘附和聚合物降解的综合调控。这证实了这一丰富的海洋细菌群体作为颗粒物质降解者的作用。海洋拟杆菌门的蛋白酶数量明显多于 GHs，而非海洋拟杆菌门的两者数量相当。含蛋白菌的拟杆菌门有两个特点：基因组小，每 Mb 参与 CO2 固定的基因数量多。后者可能很重要，因为在富含营养的光照海洋表面自由漂浮时，需要以此来生存。
