Abundance and Activity of Soil Actinomycetes from Livingston Island, Antarctica

M. ENCHEVA1, N. ZAHARIEVA1, A. KENAROVA1, N. CHIPEV2, V. CHIPEVA1, P. HRISTOVA1, I. IVANOVA1 and P. MONCHEVA1
1 Sofia University, Biological Faculty, BG – 1164 Sofia, Bulgaria
2 Institute of Biodiversity and Ecosystem Research, BG – 1113 Sofia, Bulgaria

Abstract

Encheva, M., N. Zaharieva, A. Kenarova, N. Chipev, V. Chipeva, P. HRISTOVA, I. Ivanova and P. Moncheva, 2013. Abundance and activity of soil actinomycetes from Livingston Island, Antarctica. Bulg. J. Agric. Sci., Supplement 2, 19: 68–71

 

The soils of Antarctica are severe environments inhabited by well adapted microorganisms, the knowledge of which is scarce. The study on their abundance, diversity and physiology will provide the investigators with new data on the mechanisms of their adaptation and gives new opportunities to isolate microorganisms with unique properties for practical use. The aim of the present work was to study bacterial abundance including actinomycetes and physiological diversity of Antarctic soils, by agar plate method and BIOLOG EcoPlates technique, respectively, and based on this actinomycete strains to be isolated, identified and screened for antimicrobial activity against different test bacteria. The objectives of our investigation were seven Antarctic soils taken from moss, Deschampsia vegetated and fell field habitats of Livingston Island. Some of the soil physicochemical parameters, like pH, moisture and humus, were determined. Bacterial physiological activity and diversity were assessed based on the average color development of EcoPlate wells, and community capacity to utilize different chemical categories of carbon sources, respectively. The results showed that highest physiological diversity and more intensive utilization of polyols, amino acids and phenolic compounds, and high abundance of actinomycetes characterized soil bacteria from habitats with cryptogam (moss) coverage. Most morphologically different actinomycete strains were isolated from the moss habitat denoted in the study as S6. The affiliation of the strains to genus Streptomyces was proved by the PCRamplification of 16S rDNA, using genus-specific primers. The screening of antimicrobial activity of the isolates by diffusion bioassay, using agar plugs showed that the strains synthesized antibacterial substances, active against both Gram-negative and Gram-positive bacteria. We conclude that the soils of moss habitats are favorable environments supporting high bacterial physiological activity, and high number and diversity of actinomycetes most of which are active producers of antibacterial metabolites.

Key words: Actinomycetes, antimicrobial activity, Biolog EcoPlates, PCR-amplification
Abbreviations: AWCD: average well color development; AWCDN: normalized average well color development

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