明永冰川垂直气候带中可培养低温细菌多样性分析

本研究对位于云南滇西北的明永冰川地区暖温带、中温带和寒温带三个不同垂直气候带中可培养低温细菌的多样性进行了研究。利用四种不同培养基对该地区可培养低温细菌进行了分离纯化,共得到细菌37 513株,根据菌落形态特征分为了391种,其中LB培养基分离到99种,Organic培养基分离到78种,PSG培养基分离到96种,PYGV培养基分离得到118种,可以看出寡营养培养基PYGV分离得到的细菌种类多于LB和Organnic等富营养培养基,表明PYGV针对冰川地区细菌的分离与鉴定更为合适;通过革兰氏染色和扫描电镜观察表明大部分菌株为革兰阴性杆菌;对已分离得到的优势菌进行了16S rRNA基因测序并构建系统发育树,分析得出:假单胞菌属(Pseudomonas)、耶尔森氏菌属(Yersinia)和黄杆菌属(Flavobacterium)在明永冰川不同垂直气候带上均有分布,其中假单胞菌属最多占据35%;而寡养单胞菌属(Stenotrophomonas)是寒温带上特有的菌属。本研究证明明永冰川地区垂直气候带中可培养低温细菌多样性非常丰富,也为下一步了解这一特殊地理生态环境下微生物的群落演替规律、研究冰川环境中微生物群落如何响应气候变化提供了参考。

Diversity of Culturable Low-temperature Bacteria in Vertical Climate Zones of Mingyong Glacier

In this study, we studied the diversity of culturable low-temperature bacteria in three vertical climatic zones that included warm temperate, middle temperate and cold temperate zones distributed along the Mingyong glacier in northwest of Yunnan province. Using four different media, 37 513 bacterial isolates were obtained.According to the morphological characteristics of isolate colony, 391 bacterial trains form the isolates were identified. Among them, the strains coded No. 99, 78, 96 and 118 were cultured with LB, Organic, PSG and PYGV medium respectively. PYGV medium showed more effective than that of eutrophic LB and Organnic medium in bacteria isolation in this area, which indicated that oligotrophic medium should be suitable to isolate bacteria from the glacier region. Most of isolates were gram-negative bacilli according to the results of Gram staining and scanning electron microscopic observation;parts of dominant bacterial 16 S rRNA sequences were sequenced and the phylogenetic trees were constructed as well. The studies have shown that the species of Pseudomonas, Yersinia and Flavobacterium were presence in all three vertical climatic zones in Mingyong glacier. Among them,Pseudomonas is the dominant population and occupies up to 35%, and Stenotrophomonas is a unique species distributed in cold temperate zone. Through studying the diversity of culturable low-temperature bacteria in Mingyong glacier, it would provide valuable information for the further study of microbial community in this special geographical environment as well as the reference for the understanding of how the microbial community of the glacier environment response to climate changes.