Characterization and phylogenetic analysis of novel polyene type antimicrobial metabolite producing actinomycetes from marine sediments: Bay of Bengal India

详细信息    查看全文

• 作者：Arasu M Valan ; KRT Asha ; V Duraip ; iyan ; S Ignacimuthu ; P Agastian
• 关键词：Marine Streptomyces sp. ; 16S rDNA ; Polyene antimicrobial activity ; Minimum inhibitory concentration
• 刊名：Asian Pacific Journal of Tropical Biomedicine
• 出版年：2012
• 出版时间：October, 2012
• 年：2012
• 卷：2
• 期：10
• 页码：803-810
• 全文大小：317 K

文摘

Objective

To isolate and indentify the promising antimicrobial metabolite producing Streptomyces strains from marine sediment samples from Andrapradesh coast of India.

Methods

Antagonistic actinomycetes were isolated by starch casein agar medium and modified nutrient agar medium with 1 % glucose used as a base for primary screening. Significant antimicrobial metabolite producing strains were selected and identified by using biochemical and 16S rDNA level. Minimum inhibitory concentrations of the organic extracts were done by using broth micro dilution method.

Results

Among the 210 actinomycetes, 64.3 % exhibited activity against Gram positive bacteria, 48.5 % showed activity towards Gram negative bacteria, 38.8 % exhibited both Gram positive and negative bacteria and 80.85 % isolates revealed significant antifungal activity. However, five isolates AP-5, AP-18, AP-41 and AP-70 showed significant antimicrobial activity. The analysis of cell wall hydrolysates showed the presence of LL-diaminopimelic acid and glycine in all the isolates. Sequencing analysis indicated that the isolates shared 98.5 % -99.8 % sequence identity to the 16S rDNA gene sequences of the Streptomyces taxons. The antimicrobial substances were extracted using hexane and ethyl acetate from spent medium in which strains were cultivated at 30¡ãC for five days. The antimicrobial activity was assessed using broth micro dilution technique. Each of the culture extracts from these five strains showed a typical polyene-like property. The lowest minimum inhibitory concentrations of ethyl acetate extracts against Escherichia coli and Curvularia lunata were 67.5 and 125.0 ¦Ìg/mL, respectively.

Conclusion

It can be concluded that hexane and ethyl acetate soluble extracellular products of novel isolates are effective against pathogenic bacteria and fungi.