外源甜菜碱提高恶臭假单胞菌(Pseudomonas putida)DLL-1耐盐性的研究

研究了外源甜菜碱对恶臭假单胞菌(Pseudomonas putida)DLL-1耐盐性的影响并对其渗透保护机制进行了初步的探讨;结果表明培养基中添加甜菜碱可以改善DLL-1细胞在高盐培养基中的生长情况,添加150mg/L的甜菜碱可以使DLL-1在1.2mol/L NaCl的基础盐培养基中生长,添加10mg/L的甜菜碱就足以显著缩短渗透胁迫条件下DLL-1细胞的延滞期和代时,增加生长量;和不添加对照相比,延滞期由24h缩短到6h,代时由60min缩短到35.7min,最大生长量OD610由1.29增长到1.57。在渗透胁迫条件下,细胞从外界快速吸收外源甜菜碱来代替自身相容性溶质的合成。

Glycine betaine supplied exogenously enhance salinity tolerance of Pseudomonas putida DLL-1

The salinity tolerance characteristic of Pseudomonas putida DLL-1 and the environmental factors offecting 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 osmoprotection 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 OD_(610) 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.