Metabolic enzymes in seasonally acclimatized and cold acclimated rufous-collared sparrow inhabiting a Chilean Mediterranean environment  

作　　者：Isaac PENA-VILLALOBOS Monica NUNEZ-VILLEGAS Francisco BOZINOVIC Pablo SABAT 

机构地区：[1]Departamento de Ciencias Ecologicas, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile [2]Departamento de Ecologia and Center of Applied Ecology & Sustainability (CAPES), Facultad de Ciencias Biol6gicas, Pontificia Universidad Cat61ica de Chile, Santiago 6513677, Chile

出　　处：《Current Zoology》2014年第3期338-350,共13页动物学报（英文版）

摘　　要：Due to the higher energy requirements of birds during winter, it is predicted that the activities of metabolic enzymes （e.g., citrate synthase, CS and cytochrome C oxidase, COX） should increase in tandem with increases in rates of energy expendi ture （e.g., basal metabolic rate, BMR）. However, there is mixed support for the hypothesis of enzymatic acclimatization. Fur thermore, there is little information about the effect of ambient temperature on energetics and tissue enzyme activity levels in passerines inhabiting seasonal Mediterranean environments. In this study we evaluated the interplay between BMR and enzyme activities of freshly caught individuals of the passerine Zonotrichia capensis in winter and summer in a Mediterranean environment from central Chile, and also in warm （30℃） and cold （15℃） labacclimated birds. The results revealed a lack of seasonal variation in BMR, thermal conductance and in the activity of CS and COX. However, we found higher BMR and lower thermal conductance in coldacclimated than in warmacclimated birds. Also, total CS activity was higher in the flight muscles of coldacclimated than in warmacclimated birds. We found also a significant correlation between BMR and total CS activity in pectoral muscle. Although some authors have suggested that BMR mainly depends on the metabolic intensity and mass of internal organs, our results revealed that skeletal muscles such as the flight muscles may also affect BMR. Finally, differences in the accli mation and acclimatization responses in Rufouscollared sparrows suggest that largescale oscillations in the physical environment might maintain the capacity for flexibility in thermogenic traits through generations .

关 键 词：Basal metabolic rate Citrate synthase Cytochrome C oxidase Phenotypic flexibility Thermal acclimation Zonotrichia capensis 

分 类 号：S831[农业科学—畜牧学] S435.112.3[农业科学—畜牧兽医]