Aguayo Paulina, González Paulina, Campos Víctor, Maugeri Teresa L, Papale Maria, Gugliandolo Concetta, Martinez Miguel A
Department of Microbiology, Laboratory of Basic Microbiology and Bioremedation, University of Concepción, Concepción, Chile.
Research Centre for Extreme Environments and Extremophiles, Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, V.le F. Stagno d'Alcontres, 31, 98166, Messina, Italy.
Curr Microbiol. 2017 May;74(5):598-613. doi: 10.1007/s00284-017-1209-y. Epub 2017 Mar 7.
The prokaryotic abundance and diversity in three cold, oligotrophic Patagonian lakes (Témpanos, Las Torres and Mercedes) in the northern region Aysén (Chile) were compared in winter and summer using 16S rRNA fluorescence in situ hybridization and PCR-denaturing gradient gel electrophoresis technique. Prokaryotic abundances, numerically dominated by Bacteria, were quite similar in the three lakes, but higher in sediments than in waters, and they were also higher in summer than in winter. The relative contribution of Archaea was greater in waters than in sediments, and in winter rather than in summer. Despite the phylogenetic analysis indicated that most sequences were affiliated to a few taxonomic groups, mainly referred to Proteobacteria (consisting of Beta-, Alpha- and Gammaproteobacteria) and Euryarchaeota (mainly related to uncultured methanogens), their relative abundances differed in each sample, resulting in different bacterial and archaeal assemblages. In winter, the abundance of the dominant bacterial phylotypes were mainly regulated by the increasing levels of total organic carbon in waters. Archaeal abundance and richness appeared mostly influenced by pH in winter and total nitrogen content in summer. The prokaryotic community composition at Témpanos lake, located most northerly and closer to a glacier, greatly differed in respect to the other two lakes. In this lake was detected the highest bacterial diversity, being Betaproteobacteria the most abundant group, whereas Alphaproteobacteria were distinctive of Mercedes. Archaeal community associated with sediments was mainly represent by members related to the order of Methanosarcinales at Mercedes and Las Torres lakes, and by Crenarchaeota at Témpanos lake. Our results indicate that the proximity to the glacier and the seasonality shape the composition of the prokaryotic communities in these remote lakes. These results may be used as baseline information to follow the microbial community responses to potential global changes and to anthropogenic impacts.
利用16S rRNA荧光原位杂交和PCR-变性梯度凝胶电泳技术，对智利艾森地区北部三个寒冷、贫营养的巴塔哥尼亚湖泊（Témpanos湖、Las Torres湖和Mercedes湖）冬季和夏季的原核生物丰度和多样性进行了比较。原核生物丰度以细菌为主，在三个湖泊中相当相似，但沉积物中的丰度高于水体，且夏季高于冬季。古菌在水体中的相对贡献大于沉积物，且冬季大于夏季。尽管系统发育分析表明大多数序列隶属于少数几个分类群，主要是变形菌门（包括β-、α-和γ-变形菌纲）和广古菌门（主要与未培养的产甲烷菌有关），但它们在每个样本中的相对丰度不同，导致细菌和古菌群落不同。冬季，优势细菌系统型的丰度主要受水体中总有机碳含量增加的调节。古菌丰度和丰富度在冬季似乎主要受pH值影响，夏季受总氮含量影响。位于最北部且靠近冰川的Témpanos湖的原核生物群落组成与其他两个湖泊有很大差异。在这个湖泊中检测到最高的细菌多样性，β-变形菌纲是最丰富的类群，而α-变形菌纲是Mercedes湖特有的。与沉积物相关的古菌群落，在Mercedes湖和Las Torres湖中主要由与甲烷八叠球菌目相关的成员代表，在Témpanos湖中由泉古菌门代表。我们的结果表明，靠近冰川和季节性塑造了这些偏远湖泊中原核生物群落的组成。这些结果可作为基线信息，以跟踪微生物群落对潜在全球变化和人为影响的响应。
