Antibacterial potential of streptomycete strains from Antarctic soils

Abstract

The exploration of habitats with unusual environment and poorly explored areas such as Antarctica is one of the strategies for discovery of new biologically active substances and/or new producers. The aim of this study was to identify the actinomycetes isolated from the soils of the island Livingston – Antarctica and to investigate their potential to synthesize antibacterial agents against phytopathogens. Twenty-three actinomycete strains were the object of this study. Using PCR (polymerase chain reaction) amplification all strains were affiliated to genus Streptomyces.The sequencing of the 16S rRNA for three of the strains showed greatest similarity to Streptomyces tendae for one of them, and revealed that the other strains had closest relations to streptomycetes isolated from anthropogenically unaltered regions including Antarctica.The isolates were studied for production of antibacterial substances both by molecular and culture methods. PCR targeting specific biosynthetic genes involved in the production of some groups of antibiotics was performed. The screening showed that all strains possessed the gene for Type-II polyketide synthase, 11 strains – for non-ribosomal peptide synthetase; 6 strains – for polyene antibiotics; and 4 strains – for glycopeptide antibiotics. The production of antibacterial substances by the strains was tested in vitro against phytopathogenic bacteria. The strains differed in the number of inhibited test – bacteria and in their spectrum of action. Four strains showed a wide range of activity against Gram-positive and Gram-negative phytopathogens.The results obtained revealed that the Antarctic soils are potential source for isolation of streptomycetes producing antibiotics from different groups.

Isolation and characterization of Antarctic psychrotrophStreptomycessp. strain INACH3013

“…Antarctic Streptomyces spp. with broadspectrum antibacterial activity against both Grampositive and Gram-negative bacteria were previously reported by Encheva-Malinova et al (2014). The inhibition assay was performed on different foodborne pathogenic bacteria and may not reflect the actual bacterial community in the Antarctic environment.…”

A Review on Mangrove Actinobacterial Diversity: The Roles of Streptomyces and Novel Species Discovery

“…Interestingly, Streptomyces bacteria happen to be widely distributed in extreme and underexplored environments such as deserts [70] , caves [71] , hot springs [72] , mangroves [33,73] , mountain plantations [55] , Arctic and Antarctic regions [74,75] . These environments are often characterized by certain fluctuations in environmental conditions, extreme high/low temperature, acidic/alkaline pH, limitation of nutrients, or high radiation [1] .…”

Molecular Characterization of Plasmids Harbored by Actinomycetes Isolated From the Great Salt Plains of Oklahoma Using PFGE and Next Generation Whole Genome Sequencing

“…While the majority of actinomycetes studied to date are found in terrestrial environments, these organisms have been identified in a wide range of extreme environments and marine locations. These bacteria occupy environments where the soil has a high salt concentration such as the Great Salt Plains of Oklahoma, Antarctica, and several marine locations (Hotta et al, 1980 ; Lam, 2006 ; Encheva-Malinova et al, 2014 ; Gad, 2014 ). Another variation seen in the growth pattern of actinomycetes is in the wide range of temperatures where they occur.…”