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1.
Øivind Andersen Johan B. Steen 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1986,156(6):823-828
Summary Nest humidity (
) under an incubating bantam hen was measured at ambient
ranging from 1.3 to 25.0 mmHg. Weight loss of eggs was recorded in clutches of varying size. Nest
and ambient
were also measured in wild incubating willow ptarmigan nests in dry and wet habitats.Nest
increased linearly with ambient
in a way predictable on the assumption that the water vapour conductance (
) of brood patch skin, plumage and eggs were constant and independent of ambient
. Nest
was also dependent of clutch size. Egg dehydration was quantitatively predicted from measured values and the laws of diffusion.Our findings confirm earlier conclusions that the adult bird does not actively regulate nest
at varying ambient
. Birds can presumably achieve appropriate egg dehydration by a strategy combining nest site, nest construction, egg shell conductance and incubation behaviour which meets the requirements of their breeding climate.Abbreviations
water vapur pressure
-
water vapur conductance
-
water flux 相似文献
2.
Pierre Dejours Jean-Paul Truchot 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1988,158(3):387-391
Summary In the intertidal shore crab,Carcinus maenas, pH and
values of the prebranchial venous hemolymph,
and
, the PO2 values of the arterialized cardiac hemolymph,
, were measured, and the ventilatory activity was assessed by measuring the hydrostatic pressures at the exits of the epibranchial cavities, under four environmental conditions: normoxic water, normoxic air, hypoxic gas, hyperoxic gas.In the crab breathing normoxic air,
was lower and
higher than in animals breathing normoxic water. With the switch to hypoxic gas, ventilation increased and
and
decreased. With the switch to hyperoxic gas, ventilation decreased,
and
increased and
decreased.Thus these crabs breathing air were not as well oxygenated as when breathing air-equilibrated water, and because of their low
, they were relatively hypervetilating and hypocapnic compared to air-breathing vertebrates. Hyperoxic breathing, increasing
and reducing ventilatory drive, led to increased
. Conversely,
was reduced by hypoxic breathing. These observations suggest that the gas exchanger of intertidal crabs is not as successfully designed for air breathing as that of land-colonizing insects and air-breathing vertebrates. 相似文献
3.
Gregory K. Snyder Wesley W. Weathers 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1977,117(3):291-301
Summary Resting rates of O2 consumption
against
, exercise endurance times and
during recovery from vigorous exercise were measured inSceloporus occidentalis captured near sea level and inS. graciosus captured above 2850 m. Oxygen consumption against
was also measured inS. occidentalis captured above 2850 m. When
was recorded continuously, as ambient
was slowly reduced from 155 Torr, it became directly dependent upon ambient
between 110 and 120 Torr. The critical
for the high altitude lizards was lower than that for the lowland lizards, which enabled the former to maintain relatively higher
's when ambient
was reduced below 120 Torr. The high altitude lizards also had significantly greater endurance when stimulated to exercise at 1600 m (
130 Torr). Both the higher
under hypoxia and the greater endurance roughly parallel a significantly greater maximum
in the high altitude lizards. At a simulated altitude of 3600 m (
100 Torr), maximum
and rate of recovery of the O2 debt calculated from post active
were significantly reduced in the lowland but not the high altitude lizards. The effects of simulated altitude conditions on the lowland but not the mountaine animals indicate adaptations to altitude in these sceloporine lizards. We did not find any consistent relationship between organ/body weight ratios or hematocrit and our measures of
endurance or the altitude at which the lizards were captured. 相似文献
4.
M. Christopher Barnhart 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1986,156(3):347-354
Summary Control of extracellular acid-base status was examined during activity and dormancy inOtala lactea (Pulmonata, Helicidae). Active snails showed little variation in hemolymph pH and
at constant temperature. With increase of temperature, hemolymph
increased from about 6 Torr at 5°C to 13 Torr at 24°C and pH decreased by about 0.017 pH units/°C, a pattern consistent with alphastat regulation of pH via ventilatory control of
.During dormancy, mean hemolymph
increased to about 50 Torr. Venous pH declined by about 0.4 units due to hypercapnia and fluctuated more widely than in active snails due to variability of
. Hemolymph pH declined further in prolonged dormancy due to progressive metabolic acidosis; after one year of dormancy the mean hemolymph pH was about 0.8 units lower than that of active snails at similar temperature.Active snails exposed experimentally to high
showed a large increase in hemolymph [HCO
3
–
]. However, [HCO
3
–
] declined by up to 50% during dormancy, despite the naturally occurring hypercapnia. Hemolymph osmolality and the concentrations of solutes other than [HCO
3
–
] increased with increasing duration of dormancy. Concentrations of magnesium and calcium increased about 2.5 times more rapidly than those of sodium and chloride, indicating that acidosis is partially offset by the dissolution of carbonates from the shell or tissues. 相似文献
5.
Roger S. Seymour David Vleck Carol M. Vleck 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1986,156(6):773-782
Summary The brush turkey (Alectura lathami) and mallee fowl (Leipoa ocellata) are megapode birds that incubate their eggs by burying them in mounds. Respiratory gas exchange between the buried eggs and the atmosphere occurs mainly by diffusion through about 60 cm of decomposing forest litter (brush turkey) or sand (mallee fowl).Gas fluxes in the brush turkey mound are greatly influenced by the respiration of thermophilic microorganisms which consume O2 at rates over eight times that of all of the eggs. The respiratory exchange ratio (
) of the microorganisms is 0.75 and theQ
10 for metabolism is 2.56. Fermentation and nitrogen fixation do not occur in the mounds.If the mound becomes too wet, gas tensions near the eggs can become critical because water increases rates of microbial respiration and impedes gas diffusion. However, field mounds are relatively dry, possibly because the adult bird modifies the shape of the mound and affects the entry of rain water. At egg level in field mounds,
and
are about 132 and 21 Torr, respectively, in both species. Embryonic respiration decreases
and increases
about 5 Torr in the immediate environment of individual eggs in late development. Due to a high eggshell gas conductance, which increases during incubation, the gas tensions within the shell of late embryos (
ca. 108 Torr,
ca. 47 Torr) are not far from the mean values found in species that nest above ground. 相似文献
6.
Ole Brix Gunnar Lykkeboe Kjell Johansen 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1979,129(2):97-103
Summary Oxygen binding properties of the hemocyanin-containing blood ofBuccinum undatum were examined in vitro and in vivo under normoxic (
150 mmHg) and hypoxic (
50 mmHg) conditions at 10°C. Blood pH and
showed a decrease in vivo under hypoxic conditions. Oxygen uptake at high water
, was about 18 ml O2/kg·h (wet weight) and the critical oxygen tension between 25 and 50 mm Hg. In vitro the O2 binding to hemocyanin showedn-values independent of pH, while both O2 affinity and oxygen carrying capacity were strongly pH dependent. Oxygen affinity increased below pH=8.1 and thus showed a pronounced reversed Bohr shift in the physiological pH range (7.5<pH<8.1). The oxygen carrying capacity similarly increased markedly with falling pH in the physiological pH range (reversed Root shift). Astrup titration curves showed a metabolic and respiratory acidosis under hypoxic conditions (
50 mm Hg). The role of hemocyanin in the transport of oxygen in relation to ambient O2 availability is discussed. 相似文献
7.
Mogens L. Glass James W. Hicks Marvin L. Riedesel 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1979,131(4):353-359
Summary In late February, seven box turtles were collected with body temperatures between 7 and 9°C. Ventilation, gas exchange and end-tidal
and
were recorded at 5, 10, 15 and 25°C, the animals being at each temperature for 2 to 3 weeks. There was a pronounced diurnal rhythm of breathing frequency at all temperatures. At 5°C the mean 24-h frequency was only 3.7 breaths h–1. At 15°C the frequency was 16 times higher with a 17-fold increase of ventilation. Oxygen uptake only changed from 3.4 to 12.7 ml·kg–1·h–1. Consequently, the ratio (ventilation, ml BTPS/O2 uptake, ml STPD) increased from 12.5 at 5°C to 48 at 15°C, but decreased to 24 at 25°C. The decrease of this ratio during cold exposure contrasts with an increase of the ratio during cooling earlier reported for fresh water turtles,Pseudemys. Cutaneous CO2 elimination was important at low temperature. This caused a decrease of the pulmonary gas exchange ratio so that end-tidal
remained low at 5°C in spite of an end-tidal
of only 54 Torr. 相似文献
8.
Ekkehard Liefke Dieter Kaiser Ulfert Onken 《Applied microbiology and biotechnology》1990,32(6):674-679
Summary Influence of pressure (P) and oxygen partial pressure (
) on cultivation of various Streptomyces spp. and Micromonospora purpurea was examined in pressurized air-lift and stirred tank fermenters. The maximum
was 2100 mbar. Growth and product formation of all cultures tested were markedly influenced by
higher than 1000 mbar. There is evidence that wild strains are more oxygen tolerant than production strains. At a certain
the metabolic activities of all cultures were inhibited. However, results obtained with S. aureofaciens and S. rimosus indicated an increase in specific product formation rate at elevated pressure. With increase in oxygen tension incorporation of oxygen into tetracycline molecules was enhanced. Since elevated oxygen tension can either show inhibiting effects or may be used for regulation of product formation and selectivity, the influence of
should be determined in an appropriate experimental set-up for each process.Offprint requests to: U. Onken 相似文献
9.
D. L. Evans R. J. Rose 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1988,157(6):791-799
Summary Six Standardbred horses were used to evaluate the time course of pulmonary gas exchange, ventilation, heart rate (HR) and acid base balance during different intensities of constant-load treadmill exercise. Horses were exercised at approximately 50%, 75% and 100% maximum oxygen uptake (
max) for 5 min and measurements taken every 30 s throughout exercise. At all work rates, the minute ventilation, respiratory frequency and tidal volume reached steady state values by 60 s of exercise. At 100%
max, the oxygen consumption (
) increased to mean values of approximately 130 ml/kg·min, which represents a 40-fold increase above resting
. At the low and moderate work rates,
showed no significant change from 30 s to 300 s of exercise. At the high work rate, the mean
at 30 s was 80% of the value at 300 s. The HR showed no significant change over time at the moderate work rate but differing responses at the low and high work rates. At the low work rate, the mean HR decreased from 188 beats/min at 30 s to 172 beats/min at 300 s exercise, whereas at the high work rate the mean HR increased from 204 beats/min at 30 s to 221 beats/min at 300 s exercise. No changes in acid base status occurred during exercise at the low work rate. At the moderate work rate, a mild metabolic acidosis occurred which was nonprogressive with time, whereas the high work rate resulted in a progressive metabolic acidosis with a base deficit of 16 mmol/l by 300 s exercise. It is concluded that the kinetics of gas exchange during exercise are more rapid in the horse than in man, despite the relatively greater change in
in the horse when going from rest to high intensity exercise.Symbols and abbreviations E
minute ventilation
-
V
T
tidal volume
-
oxygen uptake
-
carbon dioxide output
-
oxygen pulse
-
ventilatory equivalent for oxygen
-
ventilatory equivalent for carbon dioxide
- R
respiratory exchange ratio
- HR
heart rate
- SBC
standard bicarbonate
- STPD
standard temperature and pressure dry
- BTPS
body temperature and pressure saturated
-
arterial oxygen content
-
arteriovenous oxygen content difference
- Rf
respiratory frequency 相似文献
10.
Jacopo P. Mortola anna Noworaj 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1985,155(2):171-176
Summary The resting oxygen consumption
and breathing pattern of nine newborn and adult species (ranging in body size from mouse to human) have been compared on the basis of data collected from the literature. Minute ventilation
is similarly linked to
at both ages, the percent of
extracted as O2
about 2.2. Tidal volume/kg is an interspecies constant in newborns and adults, approximately 8 ml/kg. Breathing frequency decreases with the increase in size in a different way at the two ages: large species have newborns breathing at rates 2–3 times above the corresponding adults' values, while in the small species newborns and adults breathe at almost the same rate. Therefore the newborns of the smallest species have both
and
below the expected values, implying a greater inability to cope with the external demands than newborns of larger species. Several considerations indicate that in the smallest newborns the mechanical properties of the respiratory system could be a constraint to resting ventilations larger than observed. It is therefore possible that their low
is the cause, and not the effect, of the relatively small
. 相似文献
11.
Jack P. Hayes 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1989,159(4):453-459
Summary I compared the maximal aerobic metabolic rates (
), field metabolic rates (FMR), aerobic reserves (
-FMR), and basal metabolic rates (BMR) of wild and recently captured deer mice from low (440 m) and high (3800 m) altitudes. To separate the effects of the thermal environment from other altitudinal effects, I examined mice from different altitudes, but similar thermal environments (i.e., summer mice from high altitude and winter mice from low altitude). When the thermal environment was similar,
, FMR, and aerobic reserve of low and high altitude mice did not differ, but BMR was significantly higher at high altitude. Thus, in the absence of thermal differences, altitude had only minor effects on the aerobic metabolism of wild or recently captured deer mice.At low altitude, there was significant seasonal variation in
, FMR, and aerobic reserve, but not BMR. BMR was correlated with
, but not with FMR. The significant positive correlation of BMR with
indicates a cost of high
, because higher BMR increases food requirements and energy use during periods of thermoneutral conditions.Abbreviations
BMR
basal metabolic rate
-
FMR
field metabolic rate
-
partial pressure of oxygen
-
T
a
ambient temperature
-
T
b
body temperature
-
T
e
operative temperature
-
maximal aerobic metabolic rate 相似文献
12.
Kenth Dimberg Lars B. Höglund 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1987,157(4):405-412
Summary Carbonic anhydrase (CA) activities in gills and venous blood, acid-base balance, and haematological variables were studied during environmental hypercapnia in rainbow trout (Salmo gairdneri). Batches of 8–10 fish were exposed to about 3 or 13 mmHg
in flow-through tests of various duration from 4 h to 80 days.After initial acidosis, blood pH rose above pre-experimental values. At 3 mmHg it became normal again within 21 days, while at 13 mmHg the overshoot lasted for 80 days. In fish acclimated for 3 weeks or more to 13 mmHg
, blood HCO
3
–
increased four to five times while plasma Cl– levels were lower and K+ higher. Na+ levels did not show any consistent trend associated with exposure to hypercapnia. After an initial acidaemia, Hct, Hb, and RBC remained relatively constant.Patterns of change in CA activity differed between gills and erythrocytes. Initially, blood CA decreased at both
levels. It then began rising after about 3 weeks and tended to reach pre-experimental values by 80 day's hypercapnia. At 13 mmHg
, gill CA increased to twice the pre-experimental level. Compared with blood CA, gill CA appeared to be more specifically involved in fish acclimation to hypercapnia, which demands an increase in blood bicarbonate to provide a sufficient buffering capacity. Increased CA indicates that the gill enzyme may play a more important role than blood CA in acid-base regulation in fish during hypercapnia.Abbreviations
CA
carbonic anhydrase
-
Hb
haemoglobin
-
Hct
haematocrit value
-
RBC
red blood cells 相似文献
13.
Gill function in an elasmobranch 总被引:1,自引:0,他引:1
Gordon C. Grigg John Read 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1971,73(4):439-451
Summary Highly efficient oxygen uptake in elasmobranchs, as indicated by frequent excess of
over
has previously been ascribed to the operation of multicapillary rather than counter-current gas exchange by the gills. Analysis of models shows that, at maximum efficiency, a multicapillary system cannot account for values of
greater than
. In Port Jackson sharks Heterodontus portusjacksoni)
commonly exceeds
, which indicates the operation of a functional counter-current at the respiratory surface. The anatomical basis of this counter-current is provided by the demonstration that a continuous flow of water passes between the secondary lamellae into septal canals and thence via the parabranchial cavities to the exterior.Queen Elizabeth II Fellow. 相似文献
14.
S. Zielinski H. O. Pörtner 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1996,166(8):492-500
The intertidal wormSipunculus nudus was exposed to various temperatures for an analysis of the integrated changes in energy and acid-base status. Animals were
incubated in sea water or maintained for up to 8 days at 4 and 0°C while dwelling in the sediment. Cannulation of the animals
prior to experimentation allowed the analysis of blood gas parameters (
,
and pH).
fell to 0 torr within 8 days at 0°C. A simultaneous reduction of ventilatory activity was derived from measurements of the
pattern of coelomic fluid pressure changes associated with ventilatory movements. The increase in
and an onset of anaerobic metabolism, indicated by the accumulation of end products like acetate and propionate both in the
coelomic fluid and the body wall musculature, led to the development of a progressive acidosis and a deviation from the alphastat
regulation of intracellular pH seen in unburied animals. The drop in intracellular pH together with the depletion of the adenylates
and the phosphagen, phospho-l-arginine, reflect a significant decrease in the Gibb's free-energy change of ATP hydrolysis. These changes are interpreted
to indicate lethal cold injuries, because recovery was not possible when the animals were returned to 12°C after more than
2 days of exposure to 0°C. A low critical temperature indicating the onset of cold-induced anaerobiosis is concluded to exist
below 4°C owing to the insufficient response of the ventilatory system to the developing hypoxia. 相似文献
15.
B. Grubb G. E. Folk Jr. 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1978,128(2):185-188
Summary The rate of oxygen consumption (
) by skeletal muscle was investigated in isolated perfused hindlimbs of laboratory rats and lemmings (Lemmus). In both species,
increased in proportion to blood flow rate, even at flow rates 4–5 times above resting level. The slope of the line relating
to skeletal muscle blood flow was significantly greater in the lemming than in the rat. This may be related to the inverse relationship between body weight and metabolic rate. These data support the hypothesis that in small animals a dependent relationship exists between blood flow and skeletal muscle
. 相似文献
16.
Ronald K. Gratz 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1978,127(4):299-305
Summary Simultaneous measurements of pulmonary and cutaneous oxygen and carbon dioxide exchange, pulmonary ventilation and heart rate were made on the diamondback water snake,Natrix rhombifera at 28°C using body plethysmography. Resting lung volume, maximum lung volume and tracheal volume were also measured.The following mean values were measured in undisturbed snakes breathing room air: total (pulmonary and cutaneous) O2 uptake 46 mol · (kg min)–1; total CO2 output, 49 mol · (kg min)–1; tidal volume, 12 ml (BTPS) · kg–1; ventilatory rate, 6.9 min–1; heart rate, 42 min–1. From the measurements of tracheal volume, the effective (alveolar) ventilation was estimated as approximately 70% of total ventilation resulting in effective pulmonary
and
of 130 Torr and 20 Torr respectively. Cutaneous exchange accounted for 8.1% of the total
and 12.4% of the total
.Resting lung volume of anaesthetized snakes was 75 ml (BTPS) · kg–1, maximum lung volume was 341 ml (BTPS) · kg–1 and tracheal volume was 3.9 ml (BTPS) · kg–1. 相似文献
17.
Summary The resting membrane potential data existing in the literature for the giant axon of the squid, frog muscle and barnacle muscle have been analyzed from the standpoint of the theory of membrane potential due to Kobatake and co-workers. The average values derived for the effective charge density
(where
is a constant,
, and represents the fraction of counterions that are free, and
is the stoichiometric charge density in the membrane) present on the different biomembranes existing in their normal ionic environment are 0.3, 0.325 and 0.17 M for the squid axon, frog and barnacle muscles, respectively. On the assumption that the values of
are 0.4 and 0.2 for nerve and muscle membranes, respectively, values of 0.75, 1.62 and 0.85 M have been derived for the stoichiometric charge density
present in the respective biological membranes. These correspond to 1 negative charge per 222, 103 and 195 Å of the membrane area of the squid axon, frog and barnacle muscles, respectively. 相似文献
18.
Barbara Grubb G. E. Folk 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1976,110(2):217-226
Summary The purpose of this study was to determine the effect of norepinephrine (NE) on oxygen consumption (
) of perfused (constant flow) muscle in cold acclimated (CA) and control rats. Infusion of NE for a five minute period caused an increase in
of similar magnitude in both groups. Infusion of NE for 30 min resulted in an elevated steady state
in the cold acclimated group, while the control group showed only an initial increase in
followed by a continual decline during the remainder of the 30 min infusion period. These results suggest that when rats are challenged by cold exposure, the magnitude of the initial muscle response to NE by control and acclimated rats is the same, but a useful sustained higher muscle oxygen consumption is found only in the cold acclimated animals.Abbreviations CA
cold acclimated
- NE
norepinephrine 相似文献
19.
Takayoshi Yoshida Koji Yamamoto Masao Udo 《European journal of applied physiology and occupational physiology》1993,66(2):155-160
The purpose of the present study was to assess the relationship between the rapidity of increased gas exchange (i.e. oxygen uptake
) and increased cardiac output (
) during the transient phase following the onset of exercise. Five healthy male subjects performed multiple rest-exercise or light exercise (25 W)-exercise transitions on an electrically braked ergometer at exercise intensities of 50, 75, or 100 W for 6 min, respectively. Each transition was performed at least eight times for each load in random order. The
was obtained by a breath-by-breath method, and
was measured by an impedance method during normal breathing, using an ensemble average. On transitions from rest to exercise,
rapidly increased during phase I with time constants of 6.8–7.3 s. The
also showed a similar rapid increment with time constants of 6.0–6.8 s with an apparent increase in stroke volume (SV). In this phase I,
increased to about 29.7%–34.1% of the steady-state value and
increased to about 58.3%–87.0%. Thereafter, some 20 s after the onset of exercise a mono-exponential increase to steady-state occurred both in
and
with time constants of 26.7–32.3 and 23.7–34.4 s, respectively. The insignificant difference between
and
time constants in phase I and the abrupt increase in both
and SV at the onset of exercise from rest provided further evidence for a cardiodynamic contribution to
following the onset of exercise from rest. 相似文献
20.
B. Culik A. J. Woakes D. Adelung R. P. Wilson N. R. Coria H. J. Spairani 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1990,160(1):61-70
Summary The energy requirements of Adélie penguin (Pygoscelis adeliae) chicks were analysed with respect to body mass (W, 0.145–3.35 kg, n=36) and various forms of activity (lying, standing, minor activity, locomotion, walking on a treadmill). Direct respirometry was used to measure O2 consumption (
) and CO2 production. Heart rate (HR, bpm) was recorded from the ECG obtained by both externally attached electrodes and implantable HR-transmitters. The parameters measured were not affected by hand-rearing of the chicks or by implanting transmitters. HR measured in the laboratory and in the field were comparable. Oxygen uptake ranged from
in lying chicks to
at maximal activity, RQ=0.76. Metabolic rate in small wild chicks (0.14–0.38 kg) was not affected by time of day, nor was their feeding frequency in the colony (Dec 20–21). Regressions of HR on
were highly significant (p< 0.0001) in transmitter implanted chicks (n=4), and two relationships are proposed for the pooled data, one for minor activities (
), and one for walking (
). Oxygen consumption, mass of the chick (2–3 kg), and duration of walking (T, s) were related as
, whereas mass-specific O2 consumption was related to walking speed (S, m·s-1) as
.Abbreviations
bpm
beats per minute
-
D
distance walked (m)
-
ECG
electrocardiogram
-
HR
heart rate (bpm)
-
ns
number of steps
-
RQ
respiratory quotient
-
S
walking speed (m·s-1)
-
T
time walked (s)
-
W
body mass (kg) 相似文献