2.2. Sampling and Actinobacteria Isolation

Endemic mollusks Benedictia baicalensis (Gerstfeldt, 1859) [37] were collected from Lake Baikal near Bolshiye Koty village (51°54′19″ N 105°4′31″ E, western shore of Lake Baikal) at depths of 50 and 100 m in February 2016 using deep-water traps. Each mollusks’ sample included up to 5 specimens. Mollusks were surface-washed with sterile water, 70% ethanol, and again with sterile water to eliminate transient microorganisms. Afterwards, prepared samples were homogenized in 20% sterile glycerol and stored at −20 °C. Homogenates were thawed on ice and plated on MS plates supplemented with phosphomycin (50 µg/mL) and cycloheximide (100 µg/mL). Plates were incubated at 28 °C for 14 days. Colonies with typical for actinobacteria morphology were picked on a fresh MS plate and further characterized.