Biodiversity And Secondary Metabolite Of Antartic Fungi

Microbial secondary metabolites have been an important source of drug leadcompounds. However, with the developing of research in the general habitatmicroorganisms, the probability of discovering new strains, new activity from them isdeclining. Researchers start to look for the microbial resources of extremeenvironments. Because of unique and severe environment, the polar-derived microbeshave shown novelty in biological species and secondary metabolite, and have beenbecame new research hotspots.In this paper, we investigate the diversity of Antarctic fungi isolated from theChinese Antarctic Great Wall Station, in George King Island. In addition, we brieflyassay the cytotoxic bioactivity of these fungi, and the secondary metabolities of twoAntactic fungi were closen to research.As a result,136strains of filamentous fungi were isolated from10Antarticsamples. After dereplicated by morphologies, TLC and BOX-PCR, there are65different strains remained. All65strains were identified by ITS rDNA sequences.BLAST results of the sequences showed that the65strains belong to two groupsAscomycete and Zygomycetes, including genus Antarctomyces, Aspergillus,Cladosporium, Geomyces, Oidiodendron, Penicillium, Thelebolus, Mortierella,respectively. There are11strains which similarities are less than98%compared withthose of standard strains in NCBI database according to the BLAST results. Thesestrains can be considered as novel species. Through antitumor bioassay screening,there are12strains show cytotoxic bioactivity. Comprehensive considered theidentification results and HPLC analysis results, two strains were choose to furtherstudy.Sixteen compounds were isolated from the fermentation extracts by columnchromatography of silica gel, Sephadex LH-20and semi-preparative HPLC. Eight compounds (1-8) were isolated from strain GW31-8, including7polyketonecompounds (1-7), one benzene derivate (8). Eight compounds (9-16) were isolatedfrom strain GW8-24, including5dipeptides (9-13),1amino acid derivates (14) and2benzene derivates (15-16). Their bioactivities were on the study.Form the research above, it can be conclude that Anarctic fungi revealed thenovelty and diversity both species and secondary metabolites. So, Antarctic fungi areimportant resources for bioactive secondary metabolites and they have great value forfurther study and development.