不同降压过程对深海海水中可培养细菌群落组成的影响

【目的】控制不同的压力变化过程,比较对深海水样中可培养细菌组成的影响,探讨马里亚纳海沟深海水样中可培养细菌在不同降压处理过程下的丰度变化和群落组成。【方法】利用保压技术采集无污染、深度6001 m的深海水样后,模拟缓慢降压和快速降压过程,通过2216E培养基及2216E加氧化三甲胺(TMAO)富集培养基,对分离得到的可培养菌株进行16S rRNA基因测序分析和丰度检测。【结果】通过缓慢降压和快速降压处理后,深海海水样品中可培养细菌的丰度和群落组成差异较大。其中,在缓慢降压处理的样品中,平均丰度约为190 CFU/mL,且种群组成单一,以Bacillus属为主(占总菌落数的96%);而快速降压处理的样品中,平均丰度约为437 CFU/mL,主要分布在4个属中:Bacillus (占总菌落数的27.8%)、Achromobacter (24.4%)、Microbacterium (34.4%)和Pseudomonas (13.7%)。值得一提的是,添加TMAO后,2种降压过程处理的样品中,可培养细菌的平均丰度均没有明显提升,但样品中的可培养细菌种类明显提升,部分种属的丰度也发生了明显的变化。此外,一些种属仅在特定的压力和底物存在的条件下出现。【结论】不同的降压方式能够影响深海海水中可培养细菌的丰度和群落组成,添加TMAO的富集实验表明可以增加分离到的细菌的种类,为下一步的深入研究提供良好的研究基础。

Effect of different depressurization process on cultivable bacterial community composition of deep-sea water

Objective] The aim of this study was to compare the effect of pressure change styles on cultivable bacteria in deep-sea water sample by controlling the different pressure change process, and discuss the cultivable bacteria abundance and community composition of Mariana trench deep-sea water sample under different depressurization process. Methods] We sampled the uncontaminated deep-sea water at the depth of 6001 m without depressurization. Then, samples were treated with short-time fast depressurization and long-time slow depressurization. After that, bacteria were enriched in the 2216E or 2216E media added trimethylamine N-oxide (TMAO). The 16S rRNA gene of cultivable bacteria and their abundance were analyzed. Results] Deep-sea water treated with slow and fast depressurization differed greatly in diversity and abundance of cultivable bacteria. In sample treated with slow depressurization process, the average abundance was approximately 190 CFU/mL and Bacillus was the dominant group (96% of total colonies). However, the average abundance of fast depressurized sample was approximately 437 CFU/mL, and diverse groups including Bacillus (27.8%), Achromobacter (24.4%), Microbacterium (34.4%) and Pseudomonas (13.7%) were observed. Noticeable, addition of TMAO had little effect on abundance of cultivable bacteria of both different depressurization samples, but the diversity of both samples increased and abundance of some species obviously changed.Conclusion] Depressurization process could change the composition and abundance of cultivable bacteria in deep-sea water sample, addition of TMAO during the enrichment could increase the isolated bacterial species. These results made a solid foundation for further in-depth study of deep-sea bacteria.