Measurement of O2 consumption, CO2 production, and water vapor production in a closed system

SUMMARY We have discovered a modification of the uterus that appears to facilitate maternal-fetal communication during pregnancy in the scincid lizard Eulamprus quoyii. A vessel-dense elliptical area (VDE) on the mesometrial side of the uterus expands as the embryo grows, providing a large vascular area for physiological exchange between mother and embryo. The VDE is already developed in females with newly ovulated eggs, and is situated directly adjacent to the chorioallantois of the embryo when it develops. It is likely that signals from the early developing embryo determine the position of the VDE, as the VDE is off-centre in cases where the embryo sits obliquely in the uterus. The VDE is not a modification of the uterus over the entire chorioallantoic placenta, as the VDE is smaller than the chorioallantois after embryonic stage 33, but expansion of the VDE and growth of the chorioallantois during pregnancy are strongly correlated. The expansion of the VDE is also strongly correlated with embryonic growth and increasing embryonic oxygen demand (). We propose that angiogenic stimuli are exchanged between the VDE and the chorioallantois in E. quoyii, allowing the simultaneous growth of both tissues.

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“…Barometric pressure was recorded daily from a wall-mounted barometer. V O2 was calculated using the equations of Vleck (Vleck, 1987).…”

Section: Embryonic Respirometrymentioning

confidence: 99%

Angiogenesis of the uterus and chorioallantois in the eastern water skinkEulamprus quoyii

Murphy

Parker

Murphy

et al. 2010

Journal of Experimental Biology

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“…was measured in a closed system (Vleck 1987), Vo 2 using 60-cm 3 plastic syringes as metabolism chambers. We controlled temperature during measurement periods by submerging syringes in a circulating water bath held at 37.5ЊC.…”

Section: Measurement Of Egg Metabolismmentioning

confidence: 99%

Periodic Cooling of Bird Eggs Reduces Embryonic Growth Efficiency

Olson

Vleck

2006

Physiological and Biochemical Zoology

170

157

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For many bird embryos, periodic cooling occurs when the incubating adult leaves the nest to forage, but the effects of periodic cooling on embryo growth, yolk use, and metabolism are poorly known. To address this question, we conducted incubation experiments on eggs of zebra finches (Taeniopygia guttata) that were frequently cooled and then rewarmed or were allowed to develop at a constant temperature. After 12 d of incubation, embryo mass and yolk reserves were less in eggs that experienced periodic cooling than in controls incubated constantly at 37.5C. Embryos that regularly cooled to 20C had higher mass-specific metabolic rates than embryos incubated constantly at 37.5C. Periodic cooling delayed development and increased metabolic costs, reducing the efficiency with which egg nutrients were converted into embryo tissue. Avian embryos can tolerate periodic cooling, possibly by adjusting their physiology to variable thermal conditions, but at a cost to growth efficiency as well as rate of development. This reduction in embryo growth efficiency adds a new dimension to the fitness consequences of variation in adult nest attentiveness. Disciplines Ornithology | Other Ecology and Evolutionary Biology | Terrestrial and Aquatic Ecology | Zoology CommentsThis article is from Physiological and Biochemical Zoology 79 (2006) ABSTRACTFor many bird embryos, periodic cooling occurs when the incubating adult leaves the nest to forage, but the effects of periodic cooling on embryo growth, yolk use, and metabolism are poorly known. To address this question, we conducted incubation experiments on eggs of zebra finches (Taeniopygia guttata) that were frequently cooled and then rewarmed or were allowed to develop at a constant temperature. After 12 d of incubation, embryo mass and yolk reserves were less in eggs that experienced periodic cooling than in controls incubated constantly at 37.5ЊC. Embryos that regularly cooled to 20ЊC had higher mass-specific metabolic rates than embryos incubated constantly at 37.5ЊC. Periodic cooling delayed development and increased metabolic costs, reducing the efficiency with which egg nutrients were converted into embryo tissue. Avian embryos can tolerate periodic cooling, possibly by adjusting their physiology to variable thermal conditions, but at a cost to growth efficiency as well as rate of development. This reduction in embryo growth efficiency adds a new dimension to the fitness consequences of variation in adult nest attentiveness.

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“…We quantified _ VO 2 in offspring from both ecotypes (L-fast: n p 64, representing 20 litters from four populations; M-slow: n p 42, representing 17 litters from three populations) in each of four temperature-treatment groups (207, 247, 287, and 327C) using closed-system respirometry (Vleck 1987). Snakes were postabsorptive after fasting for 2 wk before the whole-body metabolic rate measurements, to eliminate the metabolic influence of digestion (i.e., specific dynamic action) and ensure that our measures were of maintenance metabolism (Stevenson et al 1985;Álvarez and Nicieza 2005).…”

Section: Metabolic Rate Measurementmentioning

confidence: 99%

“…Water and CO 2 were removed from air samples by injection through Drierite (Hammond Drierite, Xenio, OH) and Ascarite II (Thomas Scientific, Swedesboro, NJ), respectively, before entering the oxygen sensor. Following Vleck (1987), rates of oxygen consumption ( _ VO 2 ) were calculated as…”

Section: Metabolic Rate Measurementmentioning

confidence: 99%

Developmental and Immediate Thermal Environments Shape Energetic Trade-Offs, Growth Efficiency, and Metabolic Rate in Divergent Life-History Ecotypes of the Garter SnakeThamnophis elegans

Gangloff

Vleck²,

Bronikowski³

2015

Physiological and Biochemical Zoology

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Interactions at all levels of ecology are influenced by the rate at which energy is obtained, converted, and allocated. Tradeoffs in energy allocation within individuals in turn form the basis for life-history theory. Here we describe tests of the influences of temperature, developmental environment, and genetic background on measures of growth efficiency and resting metabolic rate in an ectothermic vertebrate, the western terrestrial garter snake (Thamnophis elegans). After raising captive-born snakes from divergent life-history ecotypes on thermal regimes mimicking natural habitat differences (2 # 2 experimental design of ecotype and thermal environment), we measured oxygen consumption rate at temperatures spanning the activity range of this species. We found ecotypic differences in the reaction norms of snakes across the measured range of temperatures and a temperature-dependent allometric relationship between mass and metabolic rate predicted by the metabolic-level boundaries hypothesis. Additionally, we present evidence of within-individual trade-offs between growth efficiency and resting metabolic rate, as predicted by classic lifehistory theory. These observations help illuminate the ultimate and proximate factors that underlie variation in these interrelated physiological and life-history traits.

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Measurement of O2 consumption, CO2 production, and water vapor production in a closed system

Cited by 151 publications

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Angiogenesis of the uterus and chorioallantois in the eastern water skinkEulamprus quoyii

Angiogenesis of the uterus and chorioallantois in the eastern water skinkEulamprus quoyii

Periodic Cooling of Bird Eggs Reduces Embryonic Growth Efficiency

Developmental and Immediate Thermal Environments Shape Energetic Trade-Offs, Growth Efficiency, and Metabolic Rate in Divergent Life-History Ecotypes of the Garter SnakeThamnophis elegans

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