Competition between cis, trans and cyclopropane fatty acid formation and its impact on membrane fluidity
Competition between cis, trans and cyclopropane fatty acid formation and its impact on membrane fluidity
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DOI：
10.1002/elsc.200620168
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发表时间：
2007-02-01
影响因子：
2.7
通讯作者：
Harms, H.
中科院分区：
文献类型：
--
作者：
Loffhagen, N.;Haertig, C.;Harms, H.
使用分批培养的恶臭假单胞菌P8和睾丸酮丛毛单胞菌ATCC 17454研究了顺式、反式和环丙烷脂肪酸对膜流动性的影响。在两种研究菌株之间观察到的主要差异是在丛毛单胞菌中缺乏合成反式不饱和脂肪酸的能力。当在30摄氏度下呈指数增长时，转移到35摄氏度增加了R putida P8的脂肪酸的反式/顺式比率从0到0.81和0到1.07，分别在脂质提取物和细胞水解产物中。在30摄氏度下延长生长时间，然后营养剥夺48小时后，反式脂肪酸不存在，但脂质提取物中的环/顺比从0.1上升到1.55，细胞水解物中的环/顺比从0.1上升到1.54。C.当在6小时后的指数期收获时，testosteroni ATCC 17454不含环脂肪酸，而在培养72小时后，在脂质提取物和细胞水解产物中，环/顺比率分别上升至0.49和0.47。在该菌株中从未观察到反式脂肪酸。增加的环/顺式和反/顺式的比例与降低的流动性测量的荧光各向异性的1，6-二苯基-1，3，5-己三烯（DPH）嵌入在双层脂质体和傅立叶变换红外（FTIR）光谱的脂质制备的细胞。环丙烷脂肪酸对膜流动性的具体影响远小于反式脂肪酸。完整细胞的R putida P8的FTIR测量证实了高效力的反式脂肪酸，以减少流动性。在诱导环丙烷脂肪酸合成的细胞中，膜保持更流化，表明这些脂肪酸的homeoviscosis的重要性较低。
The impact of cis, trans and cyclopropane fatty acids on membrane fluidity was investigated using batch-grown Pseudomonas putida P8 and Comamonas testosteroni ATCC 17454. A major difference observed between the two investigated strains is the absence of the ability to synthesize trans-unsaturated fatty acids in Comamonas. When grown exponentially at 30 degrees C, a shift to 35 degrees C increased the trans/cis ratios of the fatty acids of R putida P8 from 0 to 0.81 and 0 to 1.07, in lipid extracts and cell hydrolyzates, respectively. After prolonged growth followed by nutrient deprivation for 48 h, both at 30 degrees C, trans fatty acids were absent, but the cyclo/cis ratios rose from 0.1 to 1.55 in lipid extracts, and from 0.1 to 1.54 in cell hydrolyzates. C. testosteroni ATCC 17454 contained no cyclo fatty acids when harvested in the exponential phase after 6 h, whereas after 72 h cultivation, the cyclo/cis ratios rose to 0.49 and 0.47, in lipid extracts and cell hydrolyzates, respectively. Trans fatty acids were never observed in this strain. Increased cyclo/cis and trans/cis ratios correlated with decreased fluidity measured by the fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH) intercalated in the bilayers of liposomes and by Fourier Transform Infrared (FTIR) spectroscopy of lipids prepared from the cells. The specific effect of cyclopropane fatty acids on membrane fluidity was much smaller than that of trans fatty acids. FTIR-measurements of intact cells of R putida P8 confirmed the high potency of trans fatty acids to decrease the fluidity. In cells with induced cyclopropane fatty acid synthesis, the membranes remained more fluidized, indicating the lower importance of these fatty acids for homeoviscosis.