| Actinomycetes, as important sources of naturally occurred antibiotics, are strains for discovery of natural anti-infective agents. Also,actinomycetes was an extremely important kind of microbial resources, which produced many useful bioactive substances for human such enzymes, immunosuppressants, immune modulators, organic acids, amino acids, steroids and alkaloids,there are about45% were the secondary metabolites of actinomycetes in more than 20 000 kinds of bioactive substances till now. In order to further explore actinomycetes from the mangrove plants of Guangxi beibu gulf, 6 cultivation methods combined with14 different separation medium were used to isolate endophytic actinomycetes from 12 kinds of mangrove plants in 5 mangrove areas. The duplicate strains were removed by cultural and morphological characterization, then constructed phylogenetic tree based on 16 S r RNA gene sequence to study the diversity of endophytic actinomycetes resources in Guangxi Mangrove plant, and established bacteria repository;in order to obtain compounds with potential research value,and provide data support and practical foundation for the future development and utilization of Guangxi Beibu Gulf mangrove endophytic actinomycetes resources,provide a reference basis to protecte and investigate the actinomycetes resources of this region’s mangrove plants, The enzyme activity and antibacterial activity were tesed by point planted method and disk diffusion method, it also has great significance for the accumulation and develop the Guangxi Beibu Gulf mangrove endophytic actinomycetes medicinal microbial resources. The results can be summarized as follows:A total of 567 isolates were purified from 12 mangrove plants with 6 kinds of separation methods and media. After removing the duplicate isolates by culturaland morphological characterization on 3 kind of media, 231 purified endophytic strains were gain.Successfully identified 200 of them, by 16 S r RNA gene sequence analysis and blast with the typical strains in Ezbiocloud, they belong to 5 suborder 7 families 9genera 34 species, Nocardiopsis and Streptomyces were dominant strains, and found 12 strains’ homology lower than 98.6%, which may be a potential new species.231 purified endophytic strains were tested for their antimicrobial activities against 6 strains of bacteria, 5 drug-sensitive and 5 drug-resistant Candida albicans by point planted method and disk diffusion method. The result showed that 51, 96 and 175 isolates were found to show antimicrobial activity against at least one strain drug-sensitive Candida albicans, one strain drug-resistant Candida albicans and one tesed bacteria respectively, accounting for experimental strains 22.1%, 41.6% and 75.6% respectively. It showed that Streptomyces strains have broad antimicrobial spectrum, the rare strain as Nocardiopsis and others’ antimicrobial spectrum relative small, but the antimicrobial effect is good.The lipase, cellulase, amylase and protease activity of 231 strains of endophytic actinomycetes were tested. 147 strains showed at least one enzyme activity,there were 37 strains show four kinds of enzyme activity. Among them there are 139 strains showed lipase activity, 37 strains showed cellulase activity, 100 strains showed amylase activity, 99 strains showed protease activity.Determinated the protease activity, which produced by 5 strains endophytic actinomycetes at high salt and high alkaline reaction conditions, and compared with trypsin. The results showed the endphytic actinomycetes not only grow well at high salt and high alkaline conditions, but also has a high enzyme activity. |
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