| Abstract [eng] |
Human pathogenic bacteria are increasingly gaining antimicrobial resistance. For this reason, new natural bioactive substances are being sought. Caves, because of their oligotrophic conditions, are considered to be an excellent source of antimicrobials. Studies over the past decades have shown that the microorganisms detectable in caves are able to synthesize secondary metabolites which might inhibit the growth of pathogens. During this work, the search of genes for the synthesis of antimicrobials was carried out in strains characterized by phenotypic antimicrobial activity in the previous scientific group. Qualitative and quantitative expression analysis of the genes for the synthesis of the bioactive substances in selected strains was also performed. After gene search, it was decided to work with 3 strains - VR1, VR5 and VR26. The phylogenetic analysis of these strains showed that the VR1 strain belongs to the Rhodococcus genus and is closest to the species Rhodococcus erythreus and Nocardia coellaca. The VR5 strain belongs to the genus Arthrobacter and is the closest to the species Arthrobacter sulfureus, and the VR26 strain belongs to the genus Pseudomonas and is closest to the species Pseudomonas frederiksbergensis. The qualitative analysis of the expression revealed that the expression of the genes for the synthesis of antimicrobials took place in all 3 strains, at all stages of growth, independently to the richness of the nutrient medium. For quantitative expression analysis VR26 strain was selected. It was found that the weakest expression of the gene was carried out during exponential growth, most effectively during stationary growth. |
