title: Low temperature adaptation and the effects of cryoprotectants on mesorhizobia strains.
abstract: In this study, the tolerance of Mesorhizobium sp. ACMP18, Mesorhizobium sp. USDA3350, and Mesorhizobium temperatum LMG23931 strains, to cold and freezing were investigated. The ability to withstand freezing at -20 °C and -70 °C for 24 months was different among the studied strains and depended on the cryoprotectant used. The survivability of mesorhizobial strains at -20 °C and -70 °C was significantly improved by some cryoprotectans (glycerol and sucrose/peptone). It is worth noting that the greatest resistance to freezing was detected when stress treatments were performed in glycerol as a cryoprotectant. Using PCR analysis, cspA genes were identified in the studied strains. Their nucleotide sequences were most similar to the sequences of the corresponding genes of the Mesorhizobium species. The expression of the cspA gene in the studied bacteria was analyzed using the RT-PCR technique. The fatty acid composition of the mesorhizobia was determined at 5, 10, 15, and 28 °C. It was noticed that growth temperature significantly affected the fatty acid composition and the amounts of unsaturated fatty acids, especially that of cis-vaccenic acid (18:1ɷ(11)), increased markedly in bacterial cells cultivated at 5, 10, and 15 °C.
authors.affiliation: Department of Genetics and Microbiology, Maria Curie Sklodowska University, Lublin, Poland.
authors.forename: Sylwia
authors.initials: S
authors.lastname: Wdowiak-Wróbel
authors.affiliation: Department of Genetics and Microbiology, Maria Curie Sklodowska University, Lublin, Poland.
authors.forename: Wanda
authors.initials: W
authors.lastname: Małek
authors.affiliation: Department of Genetics and Microbiology, Maria Curie Sklodowska University, Lublin, Poland.
authors.forename: Marta
authors.initials: M
authors.lastname: Palusińska-Szysz
mesh_terms: D000220:Adaptation, Biological / Q000502:physiology*; D001426:Bacterial Proteins / Q000502:physiology; D003080:Cold Temperature; D003451:Cryoprotective Agents / Q000494:pharmacology*; D059128:Mesorhizobium / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology*; D009829:Oleic Acids / Q000378:metabolism; D010802:Phylogeny; D013312:Stress, Physiological / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D003451:Cryoprotective Agents; D009829:Oleic Acids; C065593:cis-vaccenic acid
keywords: Cold stress; Cryoprotectants; Mesorhizobium; cspA gene