Cytotoxic and antimicrobial activities of microbial proteins from mangrove soil actinomycetes of Mangalore, Dakshina Kannada

Abstract

Introduction and Aim: Actinomycetes are Gram-positive microbes that share characters of both bacteria and fungi, which are distributed uniformly across the world. The current work was focused on identification of bioactive protein compounds from soil actinomycetes isolated from mangrove region of Mangalore, Dakshina Kannada, Karnataka, India. Materials and Methods: The mangrove soil was subjected to preheat treatment; serial dilution of 10-7 was used for plating technique in triplicates. After 7 days of incubation, pure culture isolates were selected and maintained in Yeast Extract Agar (YEA) media. The isolates were examined for colony characteristics and cultivated on YEA media for detection of major metabolites including specific proteins. These extractions were tested for antimicrobial activity by well diffusion technique. Cytotoxicity assay was performed upon physical (UV) and chemical (5% H2O2) mutagen treated proliferative yeast cells. Results: In the present study, the selected mangrove habitat has proved a good source for isolating diversified actinomycetes cultures. These actinomycetes cultures served as the best source for microbial proteins having a biological activity. Protein extraction by ammonium sulfate precipitation and dialysis yielded protein components that showed antimicrobial activity against Gram positive and Gram-negative bacteria in comparison to standard streptomycin. The protein components that showed the highest antimicrobial activity were selected and preserved as antimicrobial peptides (AMPs). Further, these proteins also showed effective cytotoxic activity against proliferative yeast cells. Conclusion: Mangrove actinomycete isolates proved as one of the best natural sources for isolation of novel compounds. Specific proteins that could target antimicrobial activity as well as mechanism of programmed cell death in both cancerous and endothelial cells were initialized using yeast cells by performing cytotoxic activity against proliferative yeast cells. Keywords: Mangrove; actinomycetes; microbial protein; antimicrobial; cytotoxicity.