盐胁迫培养下的雪藻Chlamydomonas nivalis脂类GC/MS分析

Analysis of lipid in Chlamydomonas nivalis to salt stress by GC/MS

建立了雪藻Chlamydomonas nivalis样品中中性脂和游离脂肪酸的GC/MS分析方法,同时分析了方法的系统误差,并用此方法分析研究雪藻在0.25%盐浓度下胁迫时间对游离脂肪酸和中性脂的影响。结果表明：软脂酸、α-亚麻酸含量随胁迫时间变化极为显著。对游离脂肪酸含量分析时,这两种脂肪酸含量前2h内略为减少,后大幅度增大,在3-5h时分别达到最大值89.05μg/mg,71.1μg/mg（干重含量）,比初始值分别增加142.42%,216.17%,24h时降至初始值的66.88%和58.64%。而在中性脂分析中软脂酸、α-亚麻酸含量在3-15h分别降到最小值0.19μg/mg和未检出,24h又分别增至3.90μg/mg和11.66μg/mg,增幅高达354%和418%。软脂酸、α-亚麻酸直接的协调变化最终使细胞内脂不饱和度增加以抵抗高盐环境,同时这两种脂肪酸的变化与游离脂肪酸、中性脂中的饱和及不饱和脂肪酸变化呈密切正相关。因此推测软脂酸、α-亚麻酸对于雪藻调节细胞内脂肪酸不饱和度来抵抗盐胁迫有着极其重要的作用。

A GC/MS method for analyzing the free fatty acid（FFA）and neutral fat（NF）in Chlamydomonas nivalis was established,the systematic error of this method was analyzed,and the stress effect to the FFA and NF in Chlamydomonas nivalis with 0.25% NaCl stress time was studied. The results indicated that the palmitic acid and α-linolenic acid changed markedly as the stress prolonged. In the analysis of free fatty acid,they increased sharply after slightly reducing in the first 2h,and achieved their maximum 89.05μg/mg and 71.41μg/mg at the rate of 142.42% and 216.17%,then lower to 66.88% and 58.64% of the initial value at 24h. However,in the analysis of neutral fat,the palmitic acid dropped to the minimum 0.19μg/mg,as the α-linolenic acid was not detected at 3-15h. They increased to 3.90μg/mg and 11.66μg/mg at the rate of 354% and 418% at 24h separately. The change of the palmitic acid and α-linolenic acid was positively correlated with the degree of lipid unsaturation（DLU）and the unsaturated fatty acid. Those results triggered speculation that the palmitic acid and α-linolenic acid play vitally important role in regulating the DLU in Chlamydomonas nivalis cell and resisting salt stress.