Proteomics of Colwellia psychretheca at subzero temperatures

Currently awaiting publication in upcoming Special Issue: Microbiology of low water-activity habitats  (eprint available online)
Nunn, B.L., Slattery, K. Cameron, K.A., Timmins-Schiffman, E., Junge, K. (2015) Proteomics of Colwellia psychrerythraea at subzero temperatures - a life with limited movement, flexible membranes and vital DNA repair. Environmental Microbiology. 111, 9009-9014. 

 The mechanisms that enable bacteria to be metabolically active in ice at subzero temperatures have been of considerable interest to studies of polar marine and terrestrial ecology, cryobiology, astrobiology, climatology and atmospheric sciences . Despite numerous studies in the  mechanisms of sub-zero microbial activity, the true nature of these processes in marine bacteria remains elusive.  The microbial composition and metabolic activity of polar sea ice biota has been previously described using melted sea-ice samples (Deming, 2010; Junge et al., 2011). It is challenging to evaluate the adaptations that organisms adopt to facilitate their survival within these environments due to the difficulty of recreating environmental parameters within the laboratory.  For example, the simple introduction of a tracer or substrate to monitor uptake in bacteria at sub-zero temperatures requires the melting of the sample, thereby altering the natural environment. 

In this study we report the results of a long-term experiment monitoring subzero metabolic activity, growth, protein expression and new protein synthesis by Colwellia psychrerythraea strain 34H cells. In order to identify potential molecular strategies that enable 34H cells to maintain cellular integrity under sub-zero temperatures in hyper-saline environments, we examined proteomic profiles of 34H after 8 weeks of -10°C exposure.  This allowed us to confidently identify the proteins that were retained and primarily utilized in order to maintain cellular integrity.  

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