Marine myxobacteria as a source of antibiotics

Abstract

Terrestrial myxobacteria have been deeply researched over last three decades and are known for production of bioactive substances. However, there is much less compounds known from marine myxobacteria and thus it is an interesting field for the search of antibiotics. In the study three marine myxobacteria strains, namely Enhygromyxa Salina, Pseudenhygromyxa salsuginisis and Haliangium ochraceum were cultivated and screened for bioactive secondary metabolites. The strains were successfully cultivated and the most effective media for their growth was determined. Enhygromyxa Salina showed the best growth in VY/2 SWS, Pseudenhygromyxa salsuginisis in E.S. and Haliangium ochraceum in VY/2 SWS. All strains were analyzed for bioactive compounds with serial dilution tests and HPLC-MS. The analysis revealed interesting results for Pseudenhygromyxa salsuginisis. To date, no substances from this strain were known, however it was discovered that P. Salsuginis grown in VY/2 and E.S. media can produce enhygrolides. It is known that E. salina can produce this compound, which was also proved in this study. Also, H. ochraceum demonstrated production of haliangicin in this study. Haliangicin is a typical substance for H.ochaceum, thus it is a known substance from H. ochraceum. One more marine myxobacterial strain which was obtained for investigation was Plesiocystis pacifica. However, due to its slow growth and limitation of time frame of this Bachelor work, the strain had to be excluded from the experiments

The second task of this study was to isolate myxobacteria from marine soil samples. Out of 33 samples obtained from HZI storage, nine strains managed to be isolated. The strains were identified with sequencing of 16SrRNA gene and nine strains could be divided into two dominant groups. These were terrestrial myxobacteria Myxococcus fulvus (halotolerant) and Myxococcus xanthus. The strains were screened for production of bioactive substance and only known myxalamid variants were discovered.