Proteomics of Colwellia psychrerythraea at subzero temperatures - a life with limited movement, flexible membranes and vital DNA repair
Summary The mechanisms that allow psychrophilic bacteria to remain metabolically active at subzero temperatures result from form and function of their proteins. We present first proteomic evidence of physiological changes of the marine psychrophile Colwellia psychrerythraea 34H (Cp34H) after exposur...
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| Published in | Environmental microbiology Vol. 17; no. 7; pp. 2319 - 2335 |
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| Main Authors | , , , , |
| Format | Journal Article |
| Language | English |
| Published |
England
Blackwell Publishing Ltd
01.07.2015
Wiley Subscription Services, Inc |
| Subjects | |
| Online Access | Get full text |
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| Summary: | Summary
The mechanisms that allow psychrophilic bacteria to remain metabolically active at subzero temperatures result from form and function of their proteins. We present first proteomic evidence of physiological changes of the marine psychrophile Colwellia psychrerythraea 34H (Cp34H) after exposure to subzero temperatures (−1, and −10°C in ice) through 8 weeks. Protein abundance was compared between different treatments to understand the effects of temperature and time, independently and jointly, within cells transitioning to, and being maintained in ice. Parallel [3H]‐leucine and [3H]–thymidine incubations indicated active protein and DNA synthesis to −10°C. Mass spectrometry‐based proteomics identified 1763 proteins across four experimental treatments. Proteins involved in osmolyte regulation and polymer secretion were found constitutively present across all treatments, suggesting that they are required for metabolic success below 0°C. Differentially abundant protein groups indicated a reallocation of resources from DNA binding to DNA repair and from motility to chemo‐taxis and sensing. Changes to iron and nitrogen metabolism, cellular membrane structures, and protein synthesis and folding were also revealed. By elucidating vital strategies during life in ice, this study provides novel insight into the extensive molecular adaptations that occur in cold‐adapted marine organisms to sustain cellular function in their habitat. |
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| Bibliography: | Fig. S1. Average [3H]-leucine incorporation for biotriplicate samples with standard deviations of samples incubated for 24 h after either being flash frozen (black bars) in liquid nitrogen prior to incubation or being placed immediately at the incubation temperature (gray bars; see Appendix S2). Table S1. Average [3H]-leucine incorporation and [3H]-thymidine incorporation measurements from biotriplicate samples with respective standard deviations for all temperature conditions across eight time points. Table S2. Proteins that significantly decreased in abundance after 24 h at −10°C, suggesting turnover, but did not change in concentration when held at −1°C for 24 h. Table S3. Gene Ontology categories of enriched biological processes in the 137 proteins showing decreased abundance after exposure to −10°C for 8 weeks. When multiple enriched biological processes shared all contributing proteins they were combined into one row and each process's P-value is reported if it differed from the others. Count: total proteins present with significantly lower spectral counts at −10°C 8 weeks (compared to all proteins) that correlated with the Biological Process; P-value: probability that the number of proteins identified in the biological process is significant with respect to the total number of proteins from the C. psychrerythraea proteome associated with that process. Table S4. Gene Ontology categories of enriched biological processes in the 87 proteins showing increased abundance after exposure to −10°C for 8 weeks. When multiple enriched biological processes shared all contributing proteins, they were combined into one row and each process's P-value is reported if differed from the others. Count: total proteins present with significantly higher spectral counts at −10°C 8 weeks (compared with all proteins) that correlated with the Biological Process; P-value: probability that the number of proteins identified to increase in abundance in the biological process is significant with respect to the total number of proteins from the C. psychrerythraea proteome associated with that process. Appendix S1. All proteins identified from four experimental conditions in biotriplicate analyzed using MS-based proteomics with corresponding spectral counts and QSpec output signifying if significant higher or lower abundance was observed between cell states examined. Appendix S2. Details of experiments performed to test Cp34H response to flash-freezing prior to incubation at desired subzero temperature versus directly incubating at the desired temperature without flash freezing. istex:893A08D444403AD1D67D95D8969D814F7EB277A9 ArticleID:EMI12691 National Science Foundation - No. NSF-OCE 1233014; No. NSF -OPP 0739783; No. NSF-OPP 1023462; No. NSF-OPP 1304228 ark:/67375/WNG-XKBV42B5-0 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 1462-2912 1462-2920 |
| DOI: | 10.1111/1462-2920.12691 |