Bacteria are involved in many vital biogeochemical functions in aquatic ecosystems. Owing to their small size and high growth rates, they tend to be highly responsive to any changes in their environment. This potential to reflect any kind of environmental change makes them sensitive indicators towards the effect of pollutants in aquatic systems. The present study focused on investigation of change in the bacterial community structure of Hindon River in Ghaziabad in North India, in relation to the river’s pollution levels. Both spatial and temporal variation in the resident as well as active bacterial community was determined using 16S rRNA gene and transcript as molecular markers through denaturing gradient gel electrophoresis. Sequence analysis of eluted bands showed that Bacteroidetes followed by γ-proteobacteria, Actinobacteria, β-proteobacteria, δ-proteobacteria, ε-proteobacteria and Nitrospirae, represented the dominant phyla. Moreover, the effect of pollutants on the bacterial diversity was more conspicuous at RNA level. In addition, when assessing the diversity of culturables, 8 bacterial strains, having minimum inhibitory concentrations in the range of 200–250 mg l⁻¹ for Ni, 75–200 mg l⁻¹ for Co and 75–200 mg l⁻¹ for Cd, were isolated and characterized. The identified bacteria have the potential to be used as sensitive biomarkers for the development of bioremediation strategies and their monitoring.

中文翻译：

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污染塑造了河流的细菌群落：一个案例研究

细菌参与水生生态系统的许多重要生物地球化学功能。由于它们的体积小和高增长率，它们倾向于对环境的任何变化做出高度响应。这种反映任何类型的环境变化的潜力使其成为对水生系统污染物影响的敏感指标。本研究的重点是调查印度北部加兹阿巴德的兴登河细菌群落结构与河流污染水平的关系。通过变性梯度凝胶电泳，使用16S rRNA基因和转录本作为分子标记，确定了居民以及活跃细菌群落的时空变化。洗脱带的序列分析表明，拟杆菌随后为γ-proteobacteria，放线菌，β- proteobacteria，δ- proteobacteria，ε- proteobacteria和硝化螺旋菌是优势菌群。此外，污染物在RNA水平上对细菌多样性的影响更为明显。此外，评估culturables，8个细菌菌株的多样性时，在200-250毫克L的范围内具有最低抑菌浓度^-1为镍，75-200毫克升^-1为Co和75-200毫克升^-1为分离镉并进行表征。鉴定出的细菌有潜力用作开发生物修复策略及其监测的敏感生物标记。