Hofmann G E, Hand S C
Department of Environmental, Population and Organismic Biology, University of Colorado, Boulder 80309-0334.
Am J Physiol. 1990 May;258(5 Pt 2):R1184-91. doi: 10.1152/ajpregu.1990.258.5.R1184.
We have examined cytochrome-c oxidase (COX) biosynthesis in brine shrimp (Artemia franciscana) embryos during preemergence development (PED), as well as its inhibition under anaerobic dormancy, to determine whether transitions in intracellular pH (pHi) have a regulatory influence on anabolic processes. Under control aerobic conditions (embryo pHi greater than or equal to 7.9), incorporation of radiolabeled amino acids shows that substantial biosynthesis of COX occurs during 12 h of PED (500% increase when corrected for enzyme turnover). This anabolic process is blocked under anoxia, a condition known to foster intracellular acidification (pHi less than or equal to 6.8). The arrest of COX synthesis is quantitatively identical when embryos are incubated aerobically during artifical acidification with CO2 (pHi = 6.8). The data suggest that pHi, directly or indirectly, is a regulator of protein synthesis in Artemia embryos during anaerobic dormancy. Previous work has established a fundamental role for pHi in the arrest of carbohydrate catabolism under anoxia. Thus there appears to be a coordinated suppression of energy-producing and energy-utilizing events as Artemia embryos enter quiescence that involves pHi as the common intracellular signal.
我们研究了卤虫（Artemia franciscana）胚胎在出膜前发育（PED）过程中细胞色素c氧化酶（COX）的生物合成，以及其在厌氧休眠状态下的抑制情况，以确定细胞内pH值（pHi）的转变是否对合成代谢过程具有调节作用。在对照需氧条件下（胚胎pHi大于或等于7.9），放射性标记氨基酸的掺入表明，在PED的12小时内发生了大量COX的生物合成（校正酶周转后增加了500%）。这种合成代谢过程在缺氧条件下被阻断，缺氧是一种已知会促进细胞内酸化的条件（pHi小于或等于6.8）。当胚胎在人工用CO2酸化（pHi = 6.8）期间进行需氧孵育时，COX合成的停滞在数量上是相同的。数据表明，pHi直接或间接地是卤虫胚胎在厌氧休眠期间蛋白质合成的调节因子。先前的工作已经确立了pHi在缺氧条件下阻止碳水化合物分解代谢中的基本作用。因此，当卤虫胚胎进入静止状态时，似乎存在对能量产生和能量利用事件的协同抑制，其中pHi作为共同的细胞内信号。
