Lake Baikal’s ecosystem is among the oldest lacustrine ecosystems on the planet with a diverse and unique flora and fauna. Amphipods (Amphipoda, Crustacea) are one of the most diverse groups among the lake’s invertebrate animals. The lake contains more than 350 species and subspecies of amphipods, and each of these species play a significant role in the lake’s food webs. However, their relationships with microorganisms are poorly investigated, which leaves gaps in understanding the relations between aquatic crustaceans and bacteria. We studied the diversity of a specific group of culturable microorganisms (Actinobacteria), and their possible relations with deepwater endemic amphipods present in Lake Baikal. We found that while 73% of the isolated strains belong to the widely distributed genus of Streptomyces, 27% of the isolates belong to rare genera such as Amycolatopsis, Micromonospora, and Pseudonocardia. Fifty-three percent of the studied strains expressed antibiotic activity against Gram-positive bacteria and possess polyketide synthase (PKS) genes. Thus, Actinobacteria associated with Baikal’s endemic deepwater amphipods might both protect amphipods against pathogenic microorganisms and be an untapped source of new natural products with biosynthetic potential.

中文翻译：

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贝加尔湖深水地方性两栖动物与可培养放线菌的多样性及其生物合成能力的研究

贝加尔湖的生态系统是地球上最古老的湖泊生态系统之一，拥有多种多样且独特的动植物。两栖动物（两栖动物，甲壳纲动物）是该湖无脊椎动物中种类最多的一种。该湖包含超过350种两栖类动物和亚种，每种物种在该湖的食物网中都发挥着重要作用。但是，它们与微生物之间的关系研究很少，这在了解水生甲壳类动物与细菌之间的关系方面还存在空白。我们研究了特定种类的可培养微生物（放线菌）的多样性，以及它们与贝加尔湖中存在的深水地方性两栖动物的可能关系。我们发现，虽然73％的分离菌株属于链霉菌广泛分布的属，其中27％的分离物属于稀有属，如扁桃体病，微小单孢菌和假性心动过速。53％的研究菌株对革兰氏阳性细菌表达抗生素活性，并具有聚酮化合物合酶（PKS）基因。因此，与贝加尔湖的地方性深水两栖动物有关的放线菌可能既能保护两栖动物免受病原微生物的侵害，又可以作为具有生物合成潜力的新天然产物的未开发来源。