鲵鱼消化道细菌群落结构及多样性初步研究

采用常规分离纯化与构建16S rDNA克隆文库相结合的方法对（鲵）鱼（Miichthys miiuy）消化道细菌多样性进行了初步研究.结果表明,（鲵）鱼消化道各部位可培养细菌的菌落数量从大到小依次为前肠＞幽门胃＞中肠＞后肠＞前胃＞后胃＞口咽腔,其中肠道部位菌落数量最多.分离细菌菌株主要为杆状细菌和革兰氏阴性菌,对其中的50株典型菌株进行分子鉴定,发现它们主要属于变形菌门的γ-变形菌纲（占52.7％）和β-变形菌纲（占36.8％）,以及厚壁菌门的芽孢杆菌纲（占10.5％）;不可培养细菌16S rDNA文库克隆子主要属于γ-变形菌纲、α-变形菌纲和脱铁杆菌纲,部分序列与已报道的物种相似性较低,说明消化道中可能存在新的有待开发的肠道菌株.

Preliminary research on bacterial community structure and diversity in digestive tract of Miichthys miiuy

In this study, traditional culture-based techniques and the 16S rDNA sequencing method were used to investigate the mi- crobial community of the intestinal mucosal layer in the intestine of Miichthys miiuy. We find that the culturable bacteria in each part of M. miiuy digestive tract, sorted from most to least in number, are forefut, pylorus, midgut, hindgut, proventriculus, masticatory stomach and oropharyngeal cavity, and the intestinal tract have the largest number of bacteria colonies; the cultivable bacteria are mainly rod-shaped bacterium and gram-negative bacterium. According to molecular identification of 50 typical strains, the bacteria a- bove are affiliated with 3,-proteobacteria （52. 7% ） and 13-proteobacteria （36. 8% ） in Proteobacteria, and Bacillus in Firmicutes （10. 5% ）; uncultured bacterial 16SrDNA library clones are affiliated with γ-proteobacteria, α-proteobacteria and Deferribacteres. Their partial sequences have low similarity to the reported species, which demonstrates that a new strain may be needed to develop in the digestive tract of M. miiuy.