Isolation, Identification and Molecular Characterization of Rare Actinomycetes from Mangrove Ecosystem of Nizampatnam

Aims: Isolate and characterize the antimicrobial actinomycetes from sediments of Mangrove ecosystems of Nizampatnam located in the south coastal region of Andhra Pradesh, India. Methodology and Results: The Mangrove soil samples were collected, pre-treated and plated on asparagine-glucose agar medium. Identification of the strain was carried out by employing the polyphasic taxonomical studies including the 16S rRNA sequence based analysis. Phylogenetic tree was constructed using the Molecular Evolutionary Genetic Analysis (MEGA) version 5. The potent bioactive metabolite strain was isolated and designated as VUK-10. Further polyphasic studies revealed that the Isolate VUK-10 belongs to the genera Pseudonocardia. Phylogenetic analysis of 16S rRNA sequencing studies revealed that the strain is closely related to Pseudonocardia endophytica and the bioactive metabolites produced by the isolate inhibited Gram positive, Gram negative and Fungi. Conclusion, significance and impact of study: The isolation, characterization of the rare actinomycetes from the mangrove ecosystem will be useful for the discovery of the novel bioactive metabolites that are effective against wide range of pathogens.

Optimization of Culturing Conditions for Improved Production of Bioactive Metabolites by Pseudonocardia sp. VUK-10.

The purpose of the present study was to investigate the influence of cultural and environmental parameters affecting the growth and bioactive metabolite production of the rare strain VUK-10 of actinomycete Pseudonocardia, which exhibits a broad spectrum of in vitro antimicrobial activity against bacteria and fungi. Production of bioactive metabolites by the strain was high the in modified yeast extract-malt extract-dextrose (ISP-2) broth, as compared to other tested media. Glucose (1%) and tryptone (0.25%) were found to be the most suitable carbon and nitrogen sources, respectively, for optimum production of growth and bioactive metabolites. Maximum production of bioactive metabolites was found in the culture medium with initial pH 7 incubated with the strain for four days at 30℃, under shaking conditions. This is the first report on the optimization of bioactive metabolites by Pseudonocardia sp. VUK-10.

Regulation studies of telomerase gene in cancer cells by lentinan.

Lentinan a polysaccharide from medicinal mushroom i.e Lentinus, has been known to have anticancer properties. Telomerase activity is not observed in normal healthy cells, whereas in cancerous cells telomerase expression is high. Telomerase represents a promising cancer therapeutic target. We investigated the inhibitory effect of lentinan on telomerase reverse transcriptase gene (hTERT) which is essential for telomerase activity. To assess the transcriptional effect, DLD -1 cancer cells were cultured in the presence of various concentrations of lentinan. TRAP assay, RT-PCR analysis were performed to find telomerase activity and hTERT gene expression respectively. Since C-myc is known to regulate hTERT, expression of C-myc was also determined. Culturing cells with lentinan resulted in down regulation of hTERT and C-myc expression. These results indicate that lentinan inhibits telomerase activity by down regulating hTERT expression via suppression of C-myc in cancer cells.