泥浸汁对太湖沉积物中的好氧可培养细菌多样性的影响

【目的】研究添加泥浸汁与否对太湖沉积物中可培养细菌的影响。【方法】采用R2A培养基和添加泥浸汁R2A培养基对沉积物中细菌进行分离培养,16S r RNA基因系统发育分析比较种群结构。【结果】培养基中添加泥浸汁,可使可培养细菌的种类数量增加到1.6倍。16S r RNA基因序列分析表明,培养的优势细菌类群存在明显差别。R2A培养基上生长的细菌主要为厚壁菌门(52%)、放线菌门(24%)、变形菌门(20%)和拟杆菌门(4%),其中大部分细菌与芽孢杆菌属、假单胞菌属、节杆菌属等关系密切;而添加泥浸汁的R2A培养基上生长的细菌则主要为变形菌门(40%)、放线菌门(35%)、厚壁菌门(22.5%)和拟杆菌门(2.5%),与鞘脂单胞菌属、芽孢杆菌属、副球菌属、节杆菌属等关系密切。【结论】添加泥浸汁原始营养因子可提高沉积物中可培养细菌的多样性,提高菌种可培养效率。

Effect of sediment extract on the culturable aerobic bacterial diversity in the sediments of Taihu Lake

Objective] The study is aimed to research the effect of adding sediment extract or not on the cultivable bacterial diversity in the sediment of Taihu Lake. Methods] By using R2A medium and sediment extract R2A medium to isolate and culture the bacteria in the sediment. Phylogenetic analysis based on the 16S rRNA gene was used to identify the bacterial diversity. Results] Results showed that the amount of the bacteria cultured on sediment extract R2A increased up to 1.6 times more than that of on R2A medium. Analysis based on the similarities of 16S rRNA gene sequences of isolates presented effects on the dominant bacteria. On the R2A medium, the dominant bacterial groups were Firmicutes (52%), Actinobacteria (24%), Proteobacteria (20%) and Bacteroidetes (4%), and most of the bacteria isolated from R2A were closely related to genera Bacillus, Pseudomonas and Archrobacter. However, the dominant bacterial groups isolated from sediment extract R2A were Proteobacteria (40%), Actinobacteria (35%), Firmicutes (22.5%), and Bacteroidetes (2.5%). They are closely related to Sphingomonas, Bacillus, Paracoccus and Arthrobacter. Conclusion] Adding the original nutrient factors of the sediment extract could increase the diversity of bacteria in the sediment and help to increase the cultivable efficiency.