Mesophilic and thermotolerant actinomycetes in strongly heated soils

Mesophilic and thermotolerant actinomycetes were identified in strongly heated desert-steppe soils of Mongolia, mountainous meadow soils of the Central Caucasus, and cyanobacterial films on volcanic ash near hot springs of Kamchatka. Thermotolerant actinomycetes in these soil objects were more abundant and had a greater taxonomic diversity in comparison with mesophilic actinomycetes. Thermotolerant Streptomyces were present in all the objects, except for sample 117 from the desert-steppe soil and the cyanobacterial film on volcanic ash. Thermotolerant actinomycetes from the Micromonospora and Actinomadura genera predominated in the desert-steppe soil; representatives of the Micromonospora genus predominated in the cyanobacterial film on volcanic ash, and representatives of the Microtetraspora genus predominated in the samples of geyserite near hot springs of Kamchatka.