Effects of Fatty Acid Substitution on the Release of Enzymes by Osmotic Shock
Effects of Fatty Acid Substitution on the Release of Enzymes by Osmotic Shock
复制标题
脂肪酸替代对渗透压冲击酶释放的影响
DOI：
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发表时间：
1972
影响因子：
3.2
通讯作者：
S. L. Hackette
中科院分区：
文献类型：
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作者：
B. Rosen;S. L. Hackette
研究了大肠杆菌30E菌株（一种不饱和脂肪酸营养不良菌）在添加顺式和反式不饱和脂肪酸的培养基中通过渗透休克释放酶的情况。在补充了油酸的培养基中培养的细胞在渗透休克后释放出很大一部分环磷酸二酯酶、酸性己糖磷酸酶和5′-核苷酸酶。在精化培养基中培养的细胞在休克处理后释放的这些酶要少得多。用任何一种补充物培养的培养基在转化为球质体时都显示出这些酶的总释放，这表明在这两种情况下酶都在质周空间。用油酸或精酸作为脂肪酸来源的培养液洗涤并悬浮在含有另一种异构体的培养基中。从油酸到精料的变化导致细胞在渗透休克后释放这三种酶的能力迅速下降，因此在细胞质量增加25%的情况下，培养物对渗透休克有反应，就像在精料补充培养基中培养过夜一样。相反的实验结果是细胞对渗透休克的反应能力逐渐增强。电子显微镜数据显示，大肠杆菌的外膜因掺入酸盐而发生改变。
The release of enzymes by osmotic shock from Escherichia coli strain 30E, an unsaturated fatty acid auxotroph, was examined in culture supplemented with either cis- or trans-unsaturated fatty acids. Cultures grown in oleate-supplemented medium release a large fraction of the total cyclic phosphodiesterase, acid hexose phosphatase, and 5′-nucleotidase following osmotic shock. Cultures grown in elaidate-supplemented medium release much less of these same enzymes after shock treatment. Cultures grown with either supplementation show total release of these enzymes upon conversion to spheroplasts, demonstrating that the enzymes are in the periplasmic space in both cases. Cultures grown with either oleate or elaidate as fatty acid source were washed and suspended in medium containing the other isomer. The change from oleate to elaidate resulted in a rapid decrease in ability of the cells to release the three enzymes after osmotic shock so that within a 25% increase in cell mass the culture responded to osmotic shock as would a culture grown overnight in elaidate-supplemented medium. The reverse experiment resulted in a gradual increase in the ability of the cells to respond to osmotic shock. The outer membrane of E. coli is altered by the incorporation of elaidate, as indicated by electron microscopic data.