جستجوی مقالات مرتبط با کلیدواژه « Marine actinobacteria » در نشریات گروه « زیست شناسی »

Screening bacteria for bioactive compounds is the first step in the drug discovery programs. The aim of the present research was to achieve cytotoxic and antioxidant metabolites from actinobacteria of Persian Gulf sediments and to investigate the effects of combinations of seven treatments and six isolation media on the selective isolation process. A total of 395 actinobacterial isolates were collected from 12 sediment samples. Heat treatment and M6 medium were exhibited maximum efficiency of 34.59% and 32.82% isolation, respectively. Preliminary characterization results revealed the dominant distribution of Streptomyces like isolates in all investigated stations. Streptomyces isolates distribution followed a depth dependent frequency pattern. Approximately, 27.45% of the examined isolates could scavenge 90% of DPPH radicals in 1250 µg/ml final concentration. Exudated metabolites of potent isolates could scavenge DPPH radicals with IC50 ranges from 411 to 670 µg/ml. The results of cytotoxic activity showed that 54.9% of examined isolates exhibited LC50 lower than 1000µg/mL against Artemia cells. Extracted metabolites from 12 potent isolates exhibited LC50 range from 236.3 to 565.3 µg/ml. These results suggest the widespread distribution of the antioxidant and cytotoxic producing actinobacteria in Persian Gulf sediments and represent actinobacterial isolates as promising candidates for the discovery of microbial derived bioactive compounds.

Marine actinobacteria are virtually unlimited sources of novel secondary metabolites and are very important from therapeutic and industrial points of view. There are more than 22,000 known microbial secondary metabolites, 70% of which are produced by actinobacteria. Actinobacteria from terrestrial sources have been examined and identified since the 1950s, for many significant antibiotics, anticancer, anti-tumor and immunosuppressive activities. However, obtaining the previously discovered metabolites from terrestrial actinobacteria habitats attracted studies to different ecological habitats. The ecological role of actinobacteria in the marine environment is greatly neglected.  Currently, the existence of marine actinobacteria have received considerable attention due to the structural diversity, unique biological activities of their secondary metabolites and a growing need for the development of new and potent therapeutic agents. In recent years, newly discovered secondary metabolites have shown a range of biological activities such as antibacterial, antifungal, anticancer, antitumor, cytotoxic, anti-inflammatory, anti-parasitic, anti malaria, antiviral, antioxidant, etc. In this review, an evaluation is made on the current status of research on marine actinobacteria yielding pharmaceutically active secondary metabolites. Bioactive compounds from marine actinobacteria possess distinct chemical structures that may form the basis for synthesis of new drugs that could be used to combat resistant pathogens. With the increasing advancement in science and technology, there would be a greater demand for new bioactive compounds synthesized by actinobacteria from various marine sources in future.