南方鲇不同组织间线粒体代谢的比较研究

COMPARATIVE STUDIES ON METABOLISM OF MITOCHONDRIA ISOLATED|FROM VARIOUS TISSUES OF SOUTHERN CATFISH, SILURUS MERIDIONALIS|CHEN

  • 摘要: 采用人工繁殖的同批南方鲇(Silurus meridionalis Chen)幼鱼为研究对象,分别在7.5、10、12.5、17.5、22.5、27.5、32.5、35和37.5℃条件下测定其心脏、肾脏、肝脏、脑和白肌的线粒体呼吸率、细胞色素c氧化酶(CCO)的活性,以检测不同组织线粒体的含量及代谢特征的差异性。在27.5℃下,南方鲇心脏、肾脏、肝脏、脑和白肌线粒体状态3呼吸率分别为69.94、30.98、32.36、18.89和7.34 nmol O2/min.mg;CCO活性分别为676.54、327.46、294.34、153.23和65.73 nmol O2/min.mg。统计检验表明,状态3呼吸率和CCO活性均表现为:心脏显著高于其他4种组织(PPPPP<0.05)。在7.5℃—32.5℃范围内,南方鲇的心脏、肝脏、肾脏、脑和白肌5种组织的线粒体状态3呼吸率和CCO活性均随着温度的升高而增加,但在高温端,心脏中这两种代谢指标开始出现随温度上升而下降的趋势。在低温端(7.5℃—10℃)和高温端(35℃—37.5℃),各组织线粒体呼吸率RCR值多数小于4,在37.5℃下的心脏和7.5℃下的白肌的RCR值分别低至1.76和1.85。研究结果提示,南方鲇不同组织间线粒体含量可以由CS活性作为间接指标进行比较,而各组织间线粒体含量及其代谢能力存在较大的差异。心脏表现出高含量、高代谢能力和低的耐受高温能力;白肌为低含量、低代谢能力和低的耐受低温能力;肝脏、肾脏和脑表现为中等含量、中等活性和较高的耐受极端温度能力。

     

    Abstract: To investigate diversity of mitochondrial contents and metabolic features in various tissues, the respirationrates of mitochondria and activities of cytochrome c oxidase (CCO) in heart, kidney, liver, brain and white muscle ofsouthern catfish (Silurus meridionalis Chen) were measured at temperatures of 7.5, 10, 12.5, 17.5, 22.5, 27.5, 32.5, 35,and 37.5℃, respectively. At 27.5℃, state 3 rates were 69.94 in heart, 30.98 in kidney, 32.36 in liver, 18.89 in brain, and7.34 nmol O2 / min · mg in white muscle, respectively. And activities of CCO were 676.54 nmol O2 / min · mg in heart,compared with 327.46 in kidney, 294.34 in liver, 153.23 in brain, and 65.73 in white muscle. Statistical analysis indicatedthat either state 3 rates or activities of CCO showed the similar comparative trends among the five tissues. Eitherof the two values were significantly higher in heart than those in the other four tissues (P 0.05), and significantlylower in white muscle than those in the others (P 0.05). The two values in brain were significantly lower than those inkidney and liver, but there was no significant difference between kidney and liver. The global mitochondrial contentswere evaluated by the activity of citrate synthase (CS) in various tissues in the present study. At 27.5℃, the values were17.93 in heart, 7.20 in kidney, 8.42 in liver, 6.12 in brain, and 1.35 U / mg in white muscle, respectively. Heart presentedthe significantly highest value compared with the other four tissues, and white muscle presented the significantly lowestvalue (P 0.05). There was no significant difference for activities of CS among kidney, liver and brain. From 7.5 to32.5℃, either state 3 rates or activities of CCO increased respectively with increasing temperature in all of the five tissues.But both indexes in heart began to decline dramatically from 32.5℃ to 37.5℃. Values of the respiratory controlratio (RCR) almost were less than 4 at low (7.5℃—10℃) and high (35℃—37.5℃) temperature rang. RCR for whitemuscle at 7.5℃ and for heart at 37.5℃ presented very low values of 1.85 and 1.86, respectively. Based on the presentresults, it could be suggested that activity of CS could be used as an indirect index to compare mitochondrial contentamong various tissues in the southern catfish. And the mitochondrial content and metabolic capacity were significantlyvariable among different tissues. Heart presents with the higher mitochondrial content, higher metabolic capacity, andlower tolerable capacity against the extremely high temperatures. White muscle showed the lower mitochondrial content,lower metabolic capacity, and lower tolerable capacity against the extremely low temperature. Kidney, liver and braincharacterized by middle mitochondrial content, middle metabolic capacity of mitochondria and a higher tolerable capacityagainst the either extremely low or high temperatures.

     

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