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首页> 外文期刊>The Journal of Experimental Biology >The ontogeny of aerobic and diving capacity in the skeletal muscles of Weddell seals.
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The ontogeny of aerobic and diving capacity in the skeletal muscles of Weddell seals.

机译：Weddell海豹骨骼肌中有氧运动能力和潜水能力的个体存在。

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Our objective was to determine the ontogenetic changes in the skeletal muscles of Weddell seals that transform a non-diving pup into an elite diving adult. Muscle biopsies were collected from pups, juveniles and adults and analyzed for changes in fiber type, mitochondrial density, myoglobin concentrations and aerobic, lipolytic and anaerobic enzyme activities. The fiber type results demonstrated a decrease in slow-twitch oxidative (Type I) fibers and a significant increase in fast-twitch oxidative (Type IIA) fibers as the animals mature. In addition, the volume density of mitochondria and the activity of lipolytic enzymes significantly decreased as the seals matured. To our knowledge, this is the first quantitative account describing a decrease in aerobic fibers shifting towards an increase in fast-twitch oxidative fibers with a significant decrease in mitochondrial density as animals mature. These differences in the muscle physiology of Weddell seals are potentially due to their three very distinct stages of life history: non-diving pup, novice diving juvenile, and elite deep diving adult. During the first few weeks of life, pups are a non-diving terrestrial mammal that must rely on lanugo (natal fur) for thermoregulation in the harsh conditions of Antarctica. The increased aerobic capacity of pups, associated with increased mitochondrial volumes, acts to provide additional thermogenesis. As these future elite divers mature, their skeletal muscles transform to a more sedentary state in order to maintain the low levels of aerobic metabolism associated with long-duration diving.
机译：我们的目标是确定Weddell海豹骨骼肌的个体发育变化，从而将非潜水幼崽转变为成人潜水精英。从幼犬，少年和成年人身上采集肌肉活检样品，分析其纤维类型，线粒体密度，肌红蛋白浓度以及需氧，脂解和厌氧酶活性的变化。纤维类型的结果表明，随着动物的成熟，慢肌氧化性（I型）纤维减少，而快肌氧化性（IIA型）纤维显着增加。另外，随着密封的成熟，线粒体的体积密度和脂解酶的活性显着降低。据我们所知，这是第一个定量描述，描述了随着动物的成熟，有氧纤维的减少向快速抽搐的氧化纤维的增加转移，线粒体密度显着减少。韦德尔海豹在肌肉生理方面的这些差异可能是由于它们的生活史上三个非常不同的阶段造成的：不潜水的幼崽，初学者的潜水少年和成年的深潜成年人。在生命的最初几周内，幼崽是一种非潜水的陆生哺乳动物，在南极的恶劣条件下，它们必须依靠胎毛（天生的毛皮）进行温度调节。幼犬有氧能力的增加与线粒体体积的增加有关，可提供额外的生热作用。随着这些未来的精英潜水员的成熟，他们的骨骼肌转变为久坐状态，以维持与长时间潜水相关的低水平有氧代谢。

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