BIOLOGICAL PROPERTIES OF ACTINOBACTERIA ISOLATED FROM THE BLACK SEA MUSSELS
Odesa I.I. Mechnikov National University
Today, among various marine microorganisms, marine actinobacteria are one of the most promising groups due to their ability to produce secondary metabolites with various types of biological activity, including antimicrobial and antitumor action.
The study aimed to isolate actinobacteria from mussels of the Black Sea, to characterize some of their biological properties and to carry out primary identification by fatty acid composition.
The study was based on deep-sea samples of Black Sea mussels. Isolation was performed on oat agar with sea salt, Gause №1 and Gause №2. During the study, 14 isolates of marine actinobacteria were obtained. The morphology of colonies and cells was studied according to generally accepted methods. Identification of strains by fatty acid composition was performed by gas chromatography using an automatic system for the identification of microorganisms MIDI Sherlock, antibiotic sensitivity was evaluated by disc-diffusion method.
Microscopy of the slides stained with Pfeiffer’s magenta detected short rods located alone, in chains, V-shaped or chaotic in the cultures of most actinobacteria. In addition, filamentous cells were found in the preparations along with short rods. The cells of some of the studied strains were represented by coccal forms. The ability of strains Myt 2, Myt 6, Myt 7b to produce melanoid pigment was detected on ISP-6 and ISP-7 media. The study of the fatty acid spectrum of selected strains of actinobacteria revealed that they belong to Streptomyces genus. For actinobacteria of the Streptomyces genus, fatty acids 15:0 anteiso (from 36.05% to 33.05%), 16:0 iso (15.05% – 12.75%), 14:0 iso (4.13% – 1.87%), 17:0 anteiso (10.41% – 7.75%), 15:0 iso (14.89% – 6.64%). Evaluation of antibiotic susceptibility of isolated actinobacteria to 13 antimicrobials showed that strains were sensitive to streptomycin, kanamycin, tetracycline, gentamicin, amikacin, chloramphenicol and neomycin; resistant to penicillin, oleandomycin and nystatin. Sensitivity to amicillin, erythromycin and rifamycin was variable and strain-specific.
Primary identification of 14 cultures of marine actinobacteria isolated from deep-sea mussels of the Black Sea by fatty acid profile allowed classifying them as representatives of the Streptomyces genus. The strains were characterized by typical morphological and culture properties and showed variable susceptibility to antibiotics. According to the literature data, the Streptomyces genus alone can produce a wide spectrum of bioactive molecules. Therefore, isolation of actinobacteria from marine environments and study of their metabolite profiles is promising for the subsequent search for new antimicrobial compounds.