Comparative studies of high performance swimming in sharks II. Metabolic biochemistry of locomotor and myocardial muscle in endothermic and ectothermic sharks
| العنوان: | Comparative studies of high performance swimming in sharks II. Metabolic biochemistry of locomotor and myocardial muscle in endothermic and ectothermic sharks |
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| المؤلفون: | D. Weitz, T. Grimminger, David Smith, Jeffrey B. Graham, Diego Bernal, Kathryn A. Dickson, G. Lopez |
| المصدر: | Journal of Experimental Biology. 206:2845-2857 |
| بيانات النشر: | The Company of Biologists, 2003. |
| سنة النشر: | 2003 |
| مصطلحات موضوعية: | Physiology, Adaptation, Biological, Zoology, chemical and pharmacologic phenomena, Citrate (si)-Synthase, Aquatic Science, chemistry.chemical_compound, Lactate dehydrogenase, Animals, Citrate synthase, Thresher shark, Creatine Kinase, Molecular Biology, Swimming, Ecology, Evolution, Behavior and Systematics, chemistry.chemical_classification, L-Lactate Dehydrogenase, biology, Myocardium, Anatomy, biology.organism_classification, Enzyme assay, Enzyme, Salmon shark, chemistry, Spectrophotometry, Insect Science, Ectotherm, Muscle Fibers, Fast-Twitch, Sharks, biology.protein, Animal Science and Zoology, Creatine kinase, human activities, Body Temperature Regulation |
| الوصف: | SUMMARYMetabolic enzyme activities in red (RM) and white (WM) myotomal muscle and in the heart ventricle (HV) were compared in two lamnid sharks (shortfin mako and salmon shark), the common thresher shark and several other actively swimming shark species. The metabolic enzymes measured were citrate synthase(CS), an index of aerobic capacity, and lactate dehydrogenase (LDH), an index of anaerobic capacity. WM creatine phosphokinase (CPK) activity, an index of rapid ATP production during burst swimming, was also quantified. Enzyme activities in RM, WM and HV were similar in the two lamnid species. Interspecific comparisons of enzyme activities at a common reference temperature (20°C) show no significant differences in RM CS activity but higher CS activity in the WM and HV of the lamnid sharks compared with the other species. For the other enzymes, activities in lamnids overlapped with those of other shark species. Comparison of the HV spongy and compact myocardial layers in mako, salmon and thresher sharks reveals a significantly greater spongy CS activity in all three species but no differences in LDH activity. Adjustment of enzyme activities to in vivo RM and WM temperatures in the endothermic lamnids elevates CS and LDH in both tissues relative to the ectothermic sharks. Thus, through its enhancement of both RM and WM enzyme activity, endothermy may be an important determinant of energy supply for sustained and burst swimming in the lamnids. Although lamnid WM is differentially warmed as a result of RM endothermy, regional differences in WM CS and LDH activities and thermal sensitivities (Q10 values) were not found. The general pattern of the endothermic myotomal and ectothermic HV muscle metabolic enzyme activities in the endothermic lamnids relative to other active, ectothermic sharks parallels the general pattern demonstrated for the endothermic tunas relative to their ectothermic sister species. However, the activities of all enzymes measured are lower in lamnids than in tunas. Relative to lamnids, the presence of lower WM enzyme activities in the thresher shark (which is in the same order as the lamnids, has an RM morphology similar to that of the mako and salmon sharks and may be endothermic) suggests that other factors, such as behavior and swimming pattern, also affect shark myotomal organization and metabolic function. |
| تدمد: | 1477-9145 0022-0949 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fafd729d70613d06d7a007491a027834Test https://doi.org/10.1242/jeb.00504Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....fafd729d70613d06d7a007491a027834 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 14779145 00220949 |
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