普通和稀释培养基研究太湖沉积物可培养细菌的多样性

Bacterial diversity in the sediments of Taihu Lake by using traditional nutrient medium and dilution nutrient medium

采用普通牛肉汁培养基和 10倍稀释的普通牛肉汁培养基 (以下简称稀释培养基 )研究太湖沉积物中细菌多样性 ,发现在稀释培养基上生长的细菌数量普遍是在普通牛肉汁琼脂培养基上生长的细菌数量的 3～ 5倍。分离得到纯培养物的 16SrDNA部分序列 (5′端约 5 0 0bp)分析表明 ,不同培养基上生长的优势细菌类群存在差别 :普通培养基生长的细菌主要为γ_Proteobacteria(35. 1% ) ,其次为Actinobacteria(2 4 5 % )和Firmicutes(2 2 . 3% )等类群 ,其中大部分细菌与假单胞菌属 (Pseudomoas)、芽孢杆菌属 (Bacillus)和节杆菌属 (Archrobacter)细菌的系统关系密切 ;稀释培养基生长的细菌则主要为Actinobacteria(2 7. 1% )、Firmicutes(2 5 . 7% )、α_Proteobacteria(2 1. 4 % )和γ_Proteobacteria(15. 7% )等类群 ,与芽孢杆菌属 (Bacillus) (2 5. 7% )发育系统关系密切的细菌为优势属。研究结果表明同时采用两种培养基有助于从太湖沉积物中分离到更多种微生物。

Bacterial diversity in the sediments of Taihu Lake was studied by using traditional nutrient medium (NM) and 10-fold dilution of traditional nutrient medium (DNM). Results showed that the amount of the bacteria cultured on DNM was 3～5 times higher of those on NM. The similarities of 16S rRNA gene sequences (about 500bp of 5’-end) of 164 isolates were analyzed. The results indicated that the different concentrations of nutrient medium did have effects on the dominant bacteria. On traditional nutrient medium, the dominant bacterial groups were γ-Proteobacteria (35 1), Actinobacteria (24 5) and Firmicutes (22 3). Most of the bacteria isolated from NM were closely related to genera Pseudomonas, Bacillus and Archrobacter. However, the dominant bacterial groups isolated from DNM were Actinobacteria (27 1), Firmicutes (25 7), α-Proteobacteria (21 4) andγ-Proteobacteria (15 7). Bacillus-related strains were predominant bacteria. The conclusion is that using different concentration media will assist to isolate more and comprehensive bacteria from the sediments of Taihu Lake.