Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Life Sciences
Diurnal Variation In Mass, Metabolic Rate, And Respiratory Quotient In Anna's And Costa's Hummingbirds, Donald R. Powers
Diurnal Variation In Mass, Metabolic Rate, And Respiratory Quotient In Anna's And Costa's Hummingbirds, Donald R. Powers
Faculty Publications - Department of Biological & Molecular Science
To examine how hummingbirds that do not enter torpor at night store and utilize energy, open-circuit respirometry and a strain gauge were used to measure daily variation in 0 2 consumption (Vo2 ), C02 production, respiratory quotient (RQ), and body mass in Anna's hummingbird, Calypte anna, and Costa's hummingbird, Calypte costae. During the day, Vo2 was highly variable primarily because of dif ferences in activity among individuals. At night Vo2 varied little between individuals, but mean Vo2 was more than two times that predicted from body mass for resting, postabsorptive birds. F0.85), indicating the use of carbohydrate as a …
Osmotic Effects On Mitochondria From Two Species Of Amphibian, Bufo Marinus And Rana Catesbeiana, Jeff Duerr
Osmotic Effects On Mitochondria From Two Species Of Amphibian, Bufo Marinus And Rana Catesbeiana, Jeff Duerr
Faculty Publications - Department of Biological & Molecular Science
The effects ql ionic and/or osmotic change on skeletal muscle mitochondrial performance were investigated. Two substrates, pyruvate and glutamate, and variation in osmotic pressure from 205 to 360 mosm in KCl or mannitol/sucrose media had no effect on maximal respiratory rate (state 3) or coupling (respiratory control ratio) in either species. Over an equivalent range of osmolalities associated with dehydration, organismic maximal 02-consumption rates are severely diminished with increasing osmolalities. The data do not support a mitochondria/limit to organismic 02 consumption under dehydration. There were interspecies differences in state 3 respiration and coupling that were similar to differences noted in …