Molecular Cold Adaptation Research Articles

Comparative genomics and molecular adaptational analysis of Arthrobacter from Sikkim Himalaya provided insights into its survivability under multiple high-altitude stress

Arthrobacter is a dominant aerobic bacterium under the class Actinobacteria, known for its nutritionally versatile nature and wide prevalence in stressful environments. In the current study representative two strains of Arthrobacter, ERGS1:01 and ERGS4:06, with efficient survivability under high altitude stress conditions were selected for comparative genomic studies with their mesophilic counterparts. Physiological analysis and genome insights supported the survival of these strains under multiple high-altitude stress conditions. Molecular cold-adaptation and substitution analysis of the studied strains supported the incidence of more cold-adapted proteins for functionality at low temperatures. Studied strains preferred amino acids like serine, asparagine, lysine, tryptophan for favoring increased flexibility supporting their broad temperature survivability. To the best of our knowledge, this is the first molecular cold adaptation analysis performed for the genus Arthrobacter and has revealed that ‘aromaticity’, one of the cold-adaptor indicators, should be carefully considered while evaluating cold adaptation strategies in psychrotrophic/psychrophilic bacteria.

Complete genome sequence of Pseudomonas frederiksbergensis ERDD5:01 revealed genetic bases for survivability at high altitude ecosystem and bioprospection potential

Pseudomonas frederiksbergensis ERDD5:01 is a psychrotrophic bacteria isolated from the glacial stream flowing from East Rathong glacier in Sikkim Himalaya. The strain showed survivability at high altitude stress conditions like freezing, frequent freeze-thaw cycles, and UV-C radiations. The complete genome of 5,746,824 bp circular chromosome and a plasmid of 371,027 bp was sequenced to understand the genetic basis of its survival strategy. Multiple copies of cold-associated genes encoding cold active chaperons, general stress response, osmotic stress, oxidative stress, membrane/cell wall alteration, carbon storage/starvation and, DNA repair mechanisms supported its survivability at extreme cold and radiations corroborating with the bacterial physiological findings. The molecular cold adaptation analysis in comparison with the genome of 15 mesophilic Pseudomonas species revealed functional insight into the strategies of cold adaptation. The genomic data also revealed the presence of industrially important enzymes.