He Jian, Jiang Jian-dong, Jia Kai-zhi, Huang Xing, Li Shun-peng
Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Microbiology Department, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China.
Wei Sheng Wu Xue Bao. 2006 Feb;46(1):154-7.
The salinity tolerance characteristic of Pseudomonas putida DLL-1 and the environmental factors affecting the salinity tolerance of DLL-1 were investigated. The result showed that the enrichment of culture medium influenced the salt tolerance of DLL-1, in complete medium DLL-1 could survive higher salinities than in chemically defined medium. When inoculated to complete medium with 1mol/L NaCl, the least initial biomass guarantee DLL-1 surviving was 1/100(V/V) of the medium volumes. But when inoculated to chemically defined medium with 1mol/L NaCl, the least initial biomass guarantee DLL-1 surviving was 1/10(V/V) of the medium volumes. The effects of glycine betaine exogenously supplied on the salinity tolerance of DLL-1 and its osmo protection mechanisms were also studied. The results indicated that the glycine betaine present externally could promote the growth of DLL-1 under high salinity. 10mg/L of exogenous glycine betaine was sufficient to promote the growth condition of DLL-1 cells under high salinities. 150mg/L glycine betaine could support DLL-1 cells grow in chemically defined medium with 1.2mol/L NaCl. The presence of glycine betaine in chemically defined medium could reduce significantly the lag time and generation time and increase the final biomass of DLL-1 under salt stress. Compared with the control without exogenous glycine betaine, the lag time of the treatment with exogenous glycine betaine could be reduced from 24h to 6h, and the generation time from 60min to 35.7min, the final OD610 value of culture increased from 1.29 to 1.57. Under osmotic stress, DLL-1 cells could synthesis glycine betaine, trehalose and free amino acid as the main compatible solute. When exogenously supplied, DLL-1 cells accumulated exogenous glycine betaine rapidly from medium to balance the extracellular osmolality instead of the synthesis of compatible solutes.
研究了恶臭假单胞菌DLL-1的耐盐特性以及影响其耐盐性的环境因素。结果表明，培养基的富集影响了DLL-1的耐盐性，在完全培养基中DLL-1能在比化学限定培养基更高的盐度下存活。当接种到含1mol/L NaCl的完全培养基中时，保证DLL-1存活的最低初始生物量为培养基体积的1/100（V/V）。但当接种到含1mol/L NaCl的化学限定培养基中时，保证DLL-1存活的最低初始生物量为培养基体积的1/10（V/V）。还研究了外源添加甘氨酸甜菜碱对DLL-1耐盐性及其渗透保护机制的影响。结果表明，外源存在的甘氨酸甜菜碱可促进DLL-1在高盐度下的生长。10mg/L的外源甘氨酸甜菜碱足以促进DLL-1细胞在高盐度下的生长状况。150mg/L甘氨酸甜菜碱可支持DLL-1细胞在含1.2mol/L NaCl的化学限定培养基中生长。在化学限定培养基中存在甘氨酸甜菜碱可显著缩短盐胁迫下DLL-1的延迟期和代时，并增加其最终生物量。与不添加外源甘氨酸甜菜碱的对照相比，添加外源甘氨酸甜菜碱处理的延迟期可从24小时缩短至6小时，代时从60分钟缩短至35.7分钟，培养物的最终OD610值从1.29增加到1.57。在渗透胁迫下，DLL-1细胞可合成甘氨酸甜菜碱、海藻糖和游离氨基酸作为主要的相容性溶质。当外源添加时，DLL-1细胞从培养基中迅速积累外源甘氨酸甜菜碱以平衡细胞外渗透压，而不是合成相容性溶质。
