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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 167 (1997), S. 71-80 
    ISSN: 1432-136X
    Keywords: Key words Body temperature  ;  Metabolic rate  ;   Evaporative water loss  ;  Torpor  ;  Euthermy  ;   Thermal conductance  ;  Bat ; Chalinolobus gouldii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The thermal and metabolic physiology of Chalinolobus gouldii, an Australian vespertilionid bat, was studied in the laboratory using flow-through respirometry. Chalinolobus gouldii exhibits a clear pattern of euthermic thermoregulation, typical of endotherms with respect to body temperature and rate of oxygen consumption. The basal metabolic rate of euthermic Chalinolobus gouldii is approximately 86% of that predicted for a 17.5-g mammal and falls into the range of mass-specific basal metabolic rates ascribed to vespertilionid bats. However, like most vespertilionid bats, Chalinolobus gouldii displays extreme thermolability. It is able to enter into torpor and spontaneously arouse at ambient temperatures as low as 5 °C. Torpid bats thermoconform at moderate ambient temperature, with body temperature ≈ ambient temperature, and have a low rate of oxygen consumption determined primarily by Q 10 effects. At low ambient temperature (〈 10 °C), torpid C. gouldii begin to regulate their body temperature by increased metabolic heat production; they tend to maintain a higher body temperature at low ambient temperature than do many northern hemisphere hibernating bats. Use of torpor leads to significant energy savings. The evaporative water loss of euthermic bats is relatively high, which seems unusual for a bat whose range includes extremely arid areas of Australia, and is reduced during torpor. The thermal conductance of euthermic C. gouldii is less than that predicted for a mammal of its size. The thermal conductance is considerably lower for torpid bats at intermediate body temperature and ambient temperature, but increases to euthermic values for torpid bats when thermoregulating at low ambient temperature.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 166 (1996), S. 331-336 
    ISSN: 1432-136X
    Keywords: Respiration ; Air ; Skin ; Lamprey ; Geotria Agnatha
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract When covered by moistened lint-free gauze, the larvae (ammocoetes) of the lampreyGeotria australis survived, without apparent discomfort, for 4 days in water-saturated air at 10, 15 and 20°C. In air, the mean standard rates of O2 consumption of medium to large ammocoetes ofG. australis (000000000;=0.52 g) at 10, 15 and 20°C were 14.5, 35.7 and 52.1 μl·g−1·h−1, respectively. At 15°C, the slope of the relationship between log O2 consumption (μlO2·h−1) and log body weight for ammocoetes over a wide range in body weight was 0.987. TheQ 10s for rate of O2 consumption between 10 and 15°C, 15 and 20°C and 10 and 20°C were 4.9, 2.9 and 3.6, respectively. Our results and observations of the ammocoetes suggest that, when out of water, larvalG. australis derives most of its O2 requirements from cutaneous respiration, particularly at lower temperatures. This would be facilitated by the small size and elongate shape (and thus a relatively high surface-to-volume ratio), low metabolic rate, thin dermis, extensive subdermal capillary network and high haemoglobin concentration of larvalG. australis.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-136X
    Keywords: Key words Oxygen consumption ; Estivation ; Metabolic depression ; Acidosis ; Snail ; Helix aspersa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  We have examined metabolic depression in the land snail (Helix aspersa) during estivation, and have developed a tissue model of metabolic depression using an in vitro mantle preparation. The metabolic rate of H. aspersa is depressed by 84% in vivo within 4 weeks of onset of estivation, and this metabolic depression is accompanied by a decrease in haemolymph PO2 and pH, and an increase in haemolymph PCO2. The in vitro mantle preparation has a stable O2 consumption and energy charge, and an energy charge similar to that of mantle in vivo. The in vitro mantle is an O2-conforming tissue, with VO2 varying curvilinearly with PO2. Consequently, we have developed a mathematical method of calculating tissue VO2 at any PO2. These calculations show that under appropriate incubation conditions of pH and PO2, the mantle from estivating animals shows a stable in vitro metabolic depression of 48% compared to mantle from control snails. The extrinsic effects of PO2 and pH account for 70% of the total in vitro metabolic depression of mantle tissue; intrinsic effectors contribute a further 30%.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 166 (1996), S. 331-336 
    ISSN: 1432-136X
    Keywords: Key words Respiration ; Air ; Skin ; Lamprey ; Geotria Agnatha
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  When covered by moistened lint-free gauze, the larvae (ammocoetes) of the lamprey Geotria australis survived, without apparent discomfort, for 4 days in water-saturated air at 10, 15 and 20 °C. In air, the mean standard rates of O2 consumption of medium to large ammocoetes of G. australis (x¯=0.52 g) at 10, 15 and 20 °C were 14.5, 35.7 and 52.1 μl⋅g-1⋅h-1, respectively. At 15 °C, the slope of the relationship between log O2 consumption (μl O2⋅h-1) and log body weight for ammocoetes over a wide range in body weight was 0.987. The Q 10s for rate of O2 consumption between 10 and 15 °C, 15 and 20 °C and 10 and 20 °C were 4.9, 2.9 and 3.6, respectively. Our results and observations of the ammocoetes suggest that, when out of water, larval G. australis derives most of its O2 requirements from cutaneous respiration, particularly at lower temperatures. This would be facilitated by the small size and elongate shape (and thus a relatively high surface-to-volume ratio), low metabolic rate, thin dermis, extensive subdermal capillary network and high haemoglobin concentration of larval G. australis.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-136X
    Keywords: Oxygen consumption ; Estivation ; Metabolic depression ; Acidosis ; Snail,Helix aspersa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have examined metabolic depression in the land snail (Helix aspersa) during estivation, and have developed a tissue model of metabolic depression using an in vitro mantle preparation. The metabolic rate ofH. aspersa is depressed by 84% in vivo within 4 weeks of onset of estivation, and this metabolic depression is accompanied by a decrease in haemolymphPO2 and pH, and an increase in haemolymphPCO2. The in vitro mantle preparation has a stable O2 consumption and energy charge, and an energy charge similar to that of mantle in vivo. The in vitro mantle is an O2-conforming tissue, withVO2 varying curvilinearly withPO2. Consequently, we have developed a mathematical method of calculating tissueVO2 at anyPO2. These calculations show that under appropriate incubation conditions of pH andPO2, the mantle from estivating animals shows a stable in vitro metabolic depression of 48% compared to mantle from control snails. The extrinsic effects ofPO2 and pH account for 70% of the total in vitro metabolic depression of mantle tissue; intrinsic effectors contribute a further 30%.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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