Abstract
The article presents the results of isolation of the bacterial pathogen Pseudomonas parafulva from a diseased Siberian sturgeon (Acipenser baerii) grown in a recirculating aquaculture system. The studied diseased individuals of the Siberian sturgeon (Acipenser baerii) were characterized by reduced activity, did not consume compound feed, on the body of some individuals there were hemorrhages at the bases of the fins, as well as deep penetrating ulcers. Internal organs (liver, spleen and kidneys) and washes from open ulcers were used to isolate the bacterium. As a result of studies of biological materials, the dominant bacterium was used for further identification. The bacterium is characterized as a gram-negative, motile oxidase-positive rod, in the Voges-Proskauer and methyl red test negative, in the O/F test it is characterized as oxidative. As a result of molecular genetic analysis of the 16S rRNA gene sequence of the isolated bacterium, 99% identity with other strains of P. parafulva was determined. Subsequently, the isolated strain was named AB004, and the 16S rRNA sequence was registered in the National Center for Biotechnology Information (NCBI) database under registration number OK634400. According to the results of the physiological characteristics of AB004, the optimal indicators of cultivation in the Luria-Bertani (LB) medium are: NaCl concentration - 1%, pH value - 7.0, temperature - 37°C.