Exiguobacterium sibiricum 255-15

Exiguobacterium sibiricum (strain DSM 17290 / JCM 13490 / 255-15) was isolated from a depth of 43.6 m from a geological layer in the permafrost core of Kolyma Lowland (northeast of Siberia) estimated to be 2-3million years old. Exiguobacterium sibiricum is a psychrophilic non-spore forming Gram-positive bacterium. The cells are rod-shaped, motile with peritrichous flagella and their growth ranges are from -2.5 to 40 degrees Celsius. The cells can vary in shape and size depending on growth temperature. They occur singly, in pairs or infrequently in chains. Colonies appear orange-yellow (on TSA media). They are facultative anaerobes but grow more profusely aerobically. The nearest phylogenetic neighbors to isolate 255-15 were other Kolyma-Indigirka lowland permafrost isolates and grouped closely with the type strain (ATCC 953), isolated from skimmed milk and an Antarctic isolate of Exiguobacterium acetylicum. Through analysis of the transcriptome, experiments can be designed to study microbial survival under a variety of harsh conditions. The issue of long-term survival is of interest in the field of astrobiology. Organisms that survive such hostile environments may be used as models for understanding cellular responses on astral bodies. (EBI Integr8)