Saghatelyan Ani, Margaryan Armine, Panosyan Hovik, Birkeland Nils-Kåre
Department of Biochemistry, Microbiology and Biotechnology, Yerevan State University, Alex Manoogian 1, Yerevan 0025, Armenia.
Research Institute of Biology, Yerevan State University, Alex Manoogian 1, Yerevan 0025, Armenia.
Microorganisms. 2021 Jul 9;9(7):1473. doi: 10.3390/microorganisms9071473.
The microbial diversity of high-altitude geothermal springs has been recently assessed to explore their biotechnological potential. However, little is known regarding the microbiota of similar ecosystems located on the Armenian Highland. This review summarizes the known information on the microbiota of nine high-altitude mineralized geothermal springs (temperature range 25.8-70 °C and pH range 6.0-7.5) in Armenia and Nagorno-Karabakh. All these geothermal springs are at altitudes ranging from 960-2090 m above sea level and are located on the Alpide (Alpine-Himalayan) orogenic belt, a seismically active region. A mixed-cation mixed-anion composition, with total mineralization of 0.5 mg/L, has been identified for these thermal springs. The taxonomic diversity of hot spring microbiomes has been examined using culture-independent approaches, including denaturing gradient gel electrophoresis (DGGE), 16S rRNA gene library construction, 454 pyrosequencing, and Illumina HiSeq. The bacterial phyla Proteobacteria, Bacteroidetes, Cyanobacteria, and Firmicutes are the predominant life forms in the studied springs. Archaea mainly include the phyla Euryarchaeota, Crenarchaeota, and Thaumarchaeota, and comprise less than 1% of the prokaryotic community. Comparison of microbial diversity in springs from Karvachar with that described for other terrestrial hot springs revealed that Proteobacteria, Bacteroidetes, Actinobacteria, and Deinococcus-Thermus are the common bacterial groups in terrestrial hot springs. Contemporaneously, specific bacterial and archaeal taxa were observed in different springs. Evaluation of the carbon, sulfur, and nitrogen metabolism in these hot spring communities has revealed diversity in terms of metabolic activity. Temperature seems to be an important factor in shaping the microbial communities of these springs. Overall, the diversity and richness of the microbiota are negatively affected by increasing temperature. Other abiotic factors, including pH, mineralization, and geological history, also impact the structure and function of the microbial community. More than 130 bacterial and archaeal strains (, , and ) have been reported, some of which may be representative of novel species (sharing 91-97% sequence identity with their closest matches in GenBank) and producers of thermozymes and biomolecules with potential biotechnological applications. Whole-genome shotgun sequencing of K1, as well as of the potentially new sp. J25 and sp. K1, were performed. Most of the phyla identified by 16S rRNA were also identified using metagenomic approaches. Detailed characterization of thermophilic isolates indicate the potential of the studied springs as a source of biotechnologically valuable microbes and biomolecules.
最近对高海拔地热泉的微生物多样性进行了评估，以探索其生物技术潜力。然而，对于亚美尼亚高原类似生态系统的微生物群落却知之甚少。本综述总结了亚美尼亚和纳戈尔诺-卡拉巴赫九个高海拔矿化地热泉（温度范围25.8-70°C，pH范围6.0-7.5）微生物群落的已知信息。所有这些地热泉海拔在海平面以上960-2090米之间，位于阿尔卑斯-喜马拉雅造山带这一地震活跃区域。已确定这些温泉具有混合阳离子-混合阴离子组成，总矿化度为0.5毫克/升。已使用非培养方法研究了温泉微生物群落的分类多样性，包括变性梯度凝胶电泳（DGGE）、16S rRNA基因文库构建、454焦磷酸测序和Illumina HiSeq。变形菌门、拟杆菌门、蓝细菌门和厚壁菌门是所研究温泉中的主要生命形式。古菌主要包括广古菌门、泉古菌门和奇古菌门，占原核生物群落的比例不到1%。将卡尔瓦恰尔温泉的微生物多样性与其他陆地温泉的微生物多样性进行比较发现，变形菌门、拟杆菌门、放线菌门和嗜热栖热菌-嗜热放线菌是陆地温泉中常见的细菌类群。同时，在不同温泉中观察到了特定的细菌和古菌类群。对这些温泉群落中碳、硫和氮代谢的评估揭示了代谢活性方面的多样性。温度似乎是塑造这些温泉微生物群落的一个重要因素。总体而言，微生物群落的多样性和丰富度受到温度升高的负面影响。其他非生物因素，包括pH值、矿化度和地质历史，也会影响微生物群落的结构和功能。已报道了130多种细菌和古菌菌株（、和），其中一些可能代表新物种（与GenBank中最相似的序列具有91-97%的序列同一性）以及具有潜在生物技术应用的热酶和生物分子的生产者。对K1以及潜在的新种J25和种K1进行了全基因组鸟枪法测序。通过16S rRNA鉴定的大多数门类也使用宏基因组学方法进行了鉴定。嗜热分离株的详细表征表明，所研究的温泉有潜力成为具有生物技术价值的微生物和生物分子的来源。
