Mitochondrial Function in Seasonal Acclimatization versus Latitudinal Adaptation to Cold in the Lugworm Arenicola marina (L.)
Mitochondrial Function in Seasonal Acclimatization versus Latitudinal Adaptation to Cold in the Lugworm Arenicola marina (L.)
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沙蚕海沙沙蚕季节性适应与纬度寒冷适应中的线粒体功能 (L.)
DOI：
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发表时间：
2004
影响因子：
1.6
通讯作者：
H. Pörtner
中科院分区：
文献类型：
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作者：
A. Sommer;H. Pörtner
以前的研究在海洋外温动物从纬度渐变导致的假设，广温适应低的年平均温度是能量昂贵的。为了获得更多关于热适应的权衡和限制的信息，研究了亚极地沙蚕（Arenicola marina L.）适应夏季寒冷的白色海，并进行了比较，与北方标本从北海，无论是适应夏季温度或冬季寒冷。在夏季，从亚极地和北方蠕虫的线粒体的比较显示较高的琥珀酸氧化率和减少Arrhenius活化能（Ea）在状态3呼吸在低温下，以及较高的质子泄漏率在亚极地沙蚕。这些差异反映了亚极地蠕虫较高的有氧能力，这是需要在低但多变的环境温度下保持运动活性，然而，以代谢率升高为代价。在亚极地蠕虫中发现的柠檬酸合酶（CS）的活性较低，可能表明线粒体内代谢控制的转变。与此相反，北方沙蚕驯化冬季条件下引起线粒体CS活动平行增强线粒体呼吸速率。随着驯化温度的下降，在寒冷的条件下，在较低水平的Arabius活化能下，状态3呼吸中的显着Arabius突破温度（11°C）变得不显着（5°C）甚至消失（0°C），类似于冬眠脊椎动物的现象。冬季线粒体有氧能量生产的效率上升，质子泄漏与状态3下降与冷驯化，表示较高的呼吸控制比值和增加腺苷二磷酸/氧（ADP/O）的比率。这些转变表明代谢灵活性降低，可能是由于冬季寒冷时有氧范围的丧失和代谢抑制。因此，这些模式与高纬度地区夏季活跃，冷适应广温动物中发现的模式形成对比。
Previous studies in marine ectotherms from a latitudinal cline have led to the hypothesis that eurythermal adaptation to low mean annual temperatures is energetically costly. To obtain more information on the trade‐offs and with that the constraints of thermal adaptation, mitochondrial functions were studied in subpolar lugworms (Arenicola marina L.) adapted to summer cold at the White Sea and were compared with those in boreal specimens from the North Sea, either acclimatized to summer temperatures or to winter cold. During summer, a comparison of mitochondria from subpolar and boreal worms revealed higher succinate oxidation rates and reduced Arrhenius activation energies (Ea) in state 3 respiration at low temperatures, as well as higher proton leakage rates in subpolar lugworms. These differences reflect a higher aerobic capacity in subpolar worms, which is required to maintain motor activity at low but variable environmental temperatures—however, at the expense of an elevated metabolic rate. The lower activity of citrate synthase (CS) found in subpolar worms may indicate a shift in metabolic control within mitochondria. In contrast, acclimatization of boreal lugworms to winter conditions elicited elevated mitochondrial CS activities in parallel with enhanced mitochondrial respiration rates. With falling acclimation temperatures, the significant Arrhenius break temperature in state 3 respiration (11°C) became insignificant (5°C) or even disappeared (0°C) at lower levels of Arrhenius activation energies in the cold, similar to a phenomenon known from hibernating vertebrates. The efficiency of aerobic energy production in winter mitochondria rose as proton leakage in relation to state 3 decreased with cold acclimation, indicated by higher respiratory control ratio values and increased adenosine diphosphate/oxygen (ADP/O) ratios. These transitions indicate reduced metabolic flexibility, possibly paralleled by a loss in aerobic scope and metabolic depression during winter cold. Accordingly, these patterns contrast those found in summer‐active, cold‐adapted eurytherms at high latitudes.