三种碳源对乌梁素海好氧不产氧光合细菌群落结构的影响

好氧不产氧光合细菌(AAPB)营光合异养,在水体碳循环中起着重要作用.但是,碳源对AAPB群落结构的影响尚不明确.本文基于16S rDNA和光合反应中心合成中的关键基因——pufM基因,运用变性梯度凝胶电泳(DGGE)技术,比较分析了在微生物分离培养中常用的3种碳源(葡萄糖、丙酮酸钠、酵母提取物)对乌梁素海水体总细菌及AAPB群落结构的影响.结果表明,不同碳源诱导7~21 d后,水体总细菌群落丰富度及多样性指数均有不同程度的提升,AAPB群落则呈现先升后降的趋势.3种碳源中,丙酮酸钠添加后对总细菌及AAPB菌群的丰富度和多样性的提升效果最好.测序及系统发育结果表明,乌梁素海水体经诱导后新检测到了一些原环境中未发现的菌属,一些具有特殊碳代谢能力的菌属丰度得到了提升.本研究为充分认识和理解AAPB的生态学作用和意义,及其富集、分离和培养提供了基础依据.

Influence of three kinds of carbon source on community structure of aerobic anoxygenic phototrophic bacteria in Lake Ulansuhai

Aerobic anoxygenic phototrophic bacteria (AAPB) are photoheterotrophic microbes and play a significant role in carbon cycle in aquatic ecosystems. However, the effect of carbon source on the community structure of AAPB remains unknown presently. This study determined the influence of three carbon sources, glucose, sodium pyruvate and yeast extract common used in microbe isolation and culture on total bacteria and AAPB community structures of Lake Ulansuhai, using denaturing gradient gel electrophoresis based on the genes of 16S rDNA and pufM of photosynthetic reaction center respectively. The results showed that diversity and richness of total bacteria community had been enhanced while those of AAPB community been improved previous to 14 days then decreased, after inducing by different carbon sources for 7-21days. Among the three carbon sources, sodium pyruvate best increased the richness and diversity of both total bacteria and AAPB. Sequencing and phylogenetic analysis revealed that some taxonomic strains were discovered which failed to be determined before induction by carbon source and moreover the abundance of some strains harboring specific carbon metabolism were greatly elevated. These results may promote the appreciation for the function and significance of AAPB and provide the basis for their enrichment, isolation and culture.