Allometric scaling in centrarchid fish: origins of intra- and inter-specific variation in oxidative and glycolytic enzyme levels in muscle
Allometric scaling in centrarchid fish: origins of intra- and inter-specific variation in oxidative and glycolytic enzyme levels in muscle
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DOI：
10.1242/jeb.003897
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发表时间：
2007-11-01
影响因子：
2.8
通讯作者：
Moyes, Christopher D.
中科院分区：
文献类型：
--
作者：
Davies, Rhiannon;Moyes, Christopher D.
探讨了个体大小对代谢率、肌肉酶活性及其mRNA表达模式的影响，试图解释代谢酶异速生长变异的遗传基础。我们研究了两对姐妹物种的中央鱼类：黑鲈鱼（大口鲈鱼Micropterus salmoides和小口鲈鱼Micropterus gulieui）和太阳鱼（南瓜籽Lepomis gibbosus和蓝鳃Lepomis macrochirus）。我们的目标是评估种内和种间变异相对于身体大小的监管基础，以及深入了解谱系内的进化约束。全动物常规代谢率显示标度系数与1无显著差异，范围为（+0.87至+0.96）。然而，有显着的影响，身体大小的氧化和糖酵解酶的比活性。在每个物种中，氧化酶柠檬酸合酶（CS）的质量比活性与体型呈负比例关系，比例系数范围为-0.15至-0.19，而糖酵解酶丙酮酸激酶（PK）显示出正比例关系，比例系数范围为+0.08至+0.23。PK与CS的质量特异性酶活性的比率随体型的增加而增加，而PK与CS的mRNA转录物的比率不受影响，这表明酶的关系不仅仅是由于两个基因的转录调控。PK活性的质量依赖性差异最好解释为肌肉PK基因的转录调控; PK mRNA是种内和种间PK特异性酶活性的良好预测因子。相反，CS mRNA与CS特异性酶活性不相关，这表明转录后机制可以解释所观察到的种间和种内氧化酶的差异。
The influence of body size on metabolic rate, muscle enzyme activities and the underlying patterns of mRNA for these enzymes were explored in an effort to explain the genetic basis of allometric variation in metabolic enzymes. We studied two pairs of sister species of centrarchid fish: black bass (largemouth bass Micropterus salmoides and smallmouth bass Micropterus dolomieui) and sunfish (pumpkinseed Lepomis gibbosus and bluegill Lepomis macrochirus). Our goal was to assess the regulatory basis of both intraspecific and interspecific variation relative to body size, as well as to gain insights into the evolutionary constraints within lineages. Whole animal routine metabolic rate showed scaling coefficients not significantly different from 1, ranging from (+0.87 to +0.96). However, there were significant effects of body size on the specific activities of oxidative and glycolytic enzymes. Mass-specific activity of the oxidative enzyme citrate synthase (CS) scaled negatively with body size in each species, with scaling coefficients ranging from -0.15 to -0.19, whereas the glycolytic enzyme pyruvate kinase (PK) showed positive scaling, with scaling coefficients ranging from +0.08 to +0.23. The ratio of mass-specific enzyme activity in PK to CS increased with body size, whereas the ratio of mRNA transcripts of PK to CS was unaffected, suggesting the enzyme relationships were not due simply to transcriptional regulation of both genes. The mass-dependent differences in PK activities were best explained by transcriptional regulation of the muscle PK gene; PK mRNA was a good predictor of PK specific enzyme activity within species and between species. Conversely, CS mRNA did not correlate with CS specific enzyme activities, suggesting post-transcriptional mechanisms may explain the observed inter-specific and intraspecific differences in oxidative enzymes.