Buttke T M, Pyle A L
J Bacteriol. 1982 Nov;152(2):747-56. doi: 10.1128/jb.152.2.747-756.1982.
The effects of unsaturated fatty acid deprivation on lipid synthesis in Saccharomyces cerevisiae strain GL7 were determined by following the incorporation of [14C]acetate. Compared to yeast cells grown with oleic acid, unsaturated fatty acid-deprived cells contained 200 times as much 14C label in squalene, with correspondingly less label in 2,3-oxidosqualene and 2,3;22,23-dioxidosqualene. Cells deprived of either methionine or cholesterol did not accumulate squalene, demonstrating that the effect of unsaturated fatty acid starvation on squalene oxidation was not due to an inhibition of cell growth. Cells deprived of olefinic supplements displayed additional changes in lipid metabolism: (i) an increase in 14C-labeled diacylglycerides, (ii) a decrease in 14C-labeled triacylglycerides, and (iii) increased levels of 14C-labeled decanoic and dodecanoic fatty acids. The changes in squalene oxidation and acylglyceride metabolism in unsaturated fatty acid-deprived cells were readily reversed by adding oleic acid. Pulse-chase studies demonstrated that the [14C]squalene and 14C-labeled diacylglycerides which accumulated during starvation were further metabolized when cells were resupplemented with oleic acid. These results demonstrate that unsaturated fatty acids are essential for normal lipid metabolism in yeasts.
通过追踪[14C]乙酸盐的掺入情况，确定了不饱和脂肪酸剥夺对酿酒酵母GL7菌株脂质合成的影响。与用油酸培养的酵母细胞相比，缺乏不饱和脂肪酸的细胞中角鲨烯的14C标记量是其200倍，而2,3-氧化角鲨烯和2,3;22,23-二氧化角鲨烯中的标记量相应减少。缺乏甲硫氨酸或胆固醇的细胞不会积累角鲨烯，这表明不饱和脂肪酸饥饿对角鲨烯氧化的影响并非由于细胞生长受到抑制。缺乏烯烃补充剂的细胞在脂质代谢方面还表现出其他变化：（i）14C标记的二酰基甘油增加，（ii）14C标记的三酰基甘油减少，以及（iii）14C标记的癸酸和月桂酸水平增加。添加油酸后，缺乏不饱和脂肪酸的细胞中角鲨烯氧化和酰基甘油代谢的变化很容易逆转。脉冲追踪研究表明，饥饿期间积累的[14C]角鲨烯和14C标记的二酰基甘油在细胞重新补充油酸后会进一步代谢。这些结果表明，不饱和脂肪酸对酵母的正常脂质代谢至关重要。
