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1.
Summary
D. melanogaster males of
bb/O genetic constitution undergoing rDNA magnification were mated singly to XXbb
+/O females, yielding
bb/O male progeny, and to XNO-w sn bb
+ fameles, yielding
bb/XNO- females. The male and female offspring were scored for the bb
+ phenotype.Results show that there is a higher percentage of bb
+ flies in the
bb/O male progeny than in
bb/XNO- females progeny, in single crosses as well as in the combined data. rRNA/DNA hybridization experiments agree with this observation, by showing that the rDNA content in the progeny of premagnified flies was higher in the sons than in the daughters.These data indicate that the increase of ribosomal RNA genes is not due to a stable event such as an unequal mitotic sister exchange, whereas they do not contrast with the extracopy model. 相似文献
2.
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
3.
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
4.
Romualdo Belardinelli Thomas J. Barstow Janos Porszasz Karlman Wasserman 《European journal of applied physiology and occupational physiology》1995,70(6):487-492
To determine the change in muscle oxygenation in response to progressively increasing work rate exercise, muscle oxyhemoglobin + oxymyoglobin saturation was measured transcutaneously with near infrared spectroscopy in the vastus lateralis muscle during cycle ergometry. Studies were done in 11 subjects while gas exchange was measured breath-by-breath. As work rate was increased, tissue oxygenation initially either remained constant near resting levels or, more usually, decreased. Near the work rate and metabolic rate where significant lactic acidosis was detected by excess CO2 production (lactic acidosis threshold, LAT), muscle oxygenation decreased more steeply. As maximum oxygen uptake (
) was approached, the rate of desaturation slowed. In 8 of the 11 subjects, tissue O2 saturation reached a minimum which was sustained for 1–3 min before
was reached. The LAT correlated with both the
(r = 0.95,P < 0.0001) and the work rate (r = 0.94,P < 0.0001) at which the rate of tissue O2 desaturation accelerated. These results describe a consistent pattern in the rate of decrease in muscle oxygenation, slowly decreasing over the lower work rate range, decreasing more rapidly in the work rate range of the LAT and then slowing at about 80% of
, approaching or reaching a minimum saturation at
. 相似文献
5.
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
6.
Desulfovibrio vulgaris (strain Marburg) was grown on H2 and sulfate as sole energy source in a chemostat limited by the sulfate supply. The biomass concentration and the sulfate concentration in the culture were determined as a function of the dilution rate. From the data a K
S (saturation constant) for sulfate of 10 M, a max of 0.23 h–1, and a
of 13 g/mol were calculated. The organism was also grown in chemostat culture on H2 and sulfite, H2 and thiosulfate, and pyruvate (without sulfate).
was found to be 35 g/mol,
36 g/mol, and Y
pyr
max
10 g/mol. The growth yields are discussed with respect to ATP gains in dissimilatory sulfate reduction. 相似文献
7.
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
8.
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
9.
Summary Our report presents an analysis of the development and dynamics of the female germ line inDrosophila. Females were produced that were mosaic either for attached-X chromosomes
and a ring-X (triplo-X-diplo-X), or for
and a marked Y-chromosome
. The germ-line and genitalia of these females were analysed by direct microscopic observation or by examination of the progeny.Eggs derived from triplo-X germ cells were hardly capable of supporting development, with most of the zygotes dying during embryonic development. The analysis of the germ line was therefore carried out mainly by direct observation of histochemically stained developing oocytes in the ovaries of mosaic females.The total germ cell population of both ovaries of a female was mosaic in 22–29% of the tested animals. From this frequency of mosaicism we estimated the number of functional primordial germ cells to be betwen 3 and 6 cells at the blastoderm stage. At this stage the cell lineages for the left and right ovary are not yet separated.The germ cell population of individual ovarioles was frequently mosaic which shows that the few stem cells in an ovariole are recruited as a group and are not clonal descendants of a single ancestor cell per ovariole. An analysis of the sequential pattern of oocyte-nurse cell cysts in mosaic ovarioles revealed that neighbouring cysts tend to be of the same genotype. This suggests that the stem cells of the adult ovaries preferentially divide in bursts, one of them giving rise to two, three and sometimes even more cystocytes in a row.In addition, the foci for lethality and sterility of the triplo-X condition were determined. Non-mosaic triplo-X females (metafemales) are hardly viable and invariably sterile. Using our mosaics, the focus forlethality could be mapped to a region very near the ventral prothoracic discs. The focus forsterility resides in the genitalia, since flies with triplo-X genitalia never laid any eggs, regardless of the genotype of their ovaries. 相似文献
10.
Thermoregulation,gas exchange,and ventilation in Adelie penguins (Pygoscelis adeliae) 总被引:1,自引:0,他引:1
Mark A. Chappell Sherrie L. Souza 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1988,157(6):783-790
Summary Adelie penguins (Pygoscelis adeliae) experience a wide range of ambient temperatures (T
a) in their natural habitat. We examined body temperature (T
b), oxygen consumption (
), carbon dioxide production (
), evaporative water loss (
), and ventilation atT
a from –20 to 30 °C. Body temperature did not change significantly between –20 and 20°C (meanT
b=39.3°C).T
b increased slightly to 40.1 °C atT
a=30°C. Both
and
were constant and minimal atT
a between –10 and 20°C, with only minor increases at –20 and 30°C. The minimal
of adult penguins (mean mass 4.007 kg) was 0.0112 ml/[g·min], equivalent to a metabolic heat production (MHP) of 14.9 Watt. The respiratory exchange ratio was approximately 0.7 at allT
a. Values of
were low at lowT
a, but increased to 0.21 g/min at 30°C, equivalent to 0.3% of body mass/h. Dry conductance increased 3.5-fold between –20 and 30°C. Evaporative heat loss (EHL) comprised about 5% of MHP at lowT
a, rising to 47% of MHP atT
a=30°C. The means of ventilation parameters (tidal volume [VT], respiration frequency [f], minute volume [I], and oxygen extraction [
]) were fairly stable between –20 and 10°C (VT did not change significantly over the entireT
a range). However, there was considerable inter- and intra-individual variation in ventilation patterns. AtT
a=20–30°C,f increased 7-fold over the minimal value of 7.6 breaths/min, and I showed a similar change.
fell from 28–35% at lowT
a to 6% atT
a=30°C.Abbreviations
C
thermal conductance
-
EHL
evaporative heat loss
-
oxygen extraction
-
f
respiratory frequency
-
MHP
metabolic heat production
-
evaporative water loss
-
LCT
lower critical temperature
-
RE
respiratory exchange ratio
-
T
a
ambient temperature
-
T
b
body temperature
-
rate of oxygen consumption
-
rate of carbon dioxide production
- I
inspiratory minute volume
-
VT
tidal volume 相似文献
11.
Summary We have isolated a bobbed (bb) mutant on the free duplication Dp(1; f)122bb
+ and we have measured the rDNA content of the bb
+ and the bb loci in genetic combinations in which none of the phenomena involved in the change of the rDNA redundancy occurs. We have also measured the rDNA content of the two bb loci carried by the free duplications in two different genetic combinations: (1)
and
females in which there are two attached X chromosomes completely deleted for the nucleolus organizer (NO) regions and there-fore the only rDNA is contributed by the free duplication; (2) X/Dp122bb
+ and X/Dp122bb males, in which there are two bb loci, one on the X chromosome and the other on the X free duplication.The bb
+ and the bb duplications produced an overall increase of the rDNA content in the two genetic conditions tested.These results are not in favour of both a cis and trans effect of the regulator locus (cr
+ locus) hypothesised as being involved in the disproportionate replication of rRNA genes. 相似文献
12.
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
13.
J. Baldwin A. K. Lee 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1979,129(4):361-364
Summary Oxygen consumption rates (
) and a number of possible anaerobic end products were determined forLimaria fragilis at rest, and following active swimming.
increased up to 8-fold (=4) during swimming. Swimming did not change the concentrations ofl-lactate, alanine or arginine phosphate in the single striated fast adductor muscle. Octopine, succinate andd-lactate were not detected in the adductor muscles of resting or active animals (<0.2 moles/g wet weight).It is concluded that the slow sustained swimming displayed byLimaria utilises predominantly aerobic mechanisms of ATP production. 相似文献
14.
Roger S. Seymour David Vleck Carol M. Vleck David T. Booth 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1987,157(4):413-422
Summary Eggs of the brush turkey (BT) and mallee fowl (MF) are incubated in mounds of soil and plant litter. Humidity in BT mounds is always near saturation (>99% RH), but in MF mounds it drops to lower values in summer (x=77% RH). Despite these high humidities, the eggs lose an average of 9.5% (BT) and 12.0% (MF) of their initial mass by evaporation before hatching. The rate of evaporation
increases during incubation several-fold due to large changes in water vapor conductance of the shell
and embryonic heat production. Values of
in fully incubated eggs in mound material are about 3–6 times higher than values obtained from unincubated eggs in desiccators. This effect depends on two factors: (1)
increases with ambient humidity, especially above 80% RH, possibly because the effective site of evaporation moves out along the walls of the pores in the eggshell. (2) Structural changes of the pores due to calcium absorption by the embryo directly increase
. The first factor is most important in BT eggs and the second is dominant in MF eggs. Production of metabolic heat by the embryo increases the vapor pressure difference across the shell and further increases
, especially in mounds of high humidity. The changes in pore structure are adaptive because they produce high conductances to respiratory gases and cause normal gas tensions within the egg at the end of development, yet
is low enough in early development to prevent excessive water loss. Water not lost by evaporation or taken up by the embryo is stored and released during hatching. A small amount of mass is lost during incubation by respiratory gas exchange.Abbreviations
BT
brush turkey
-
MF
mallee fowl
-
RH
relative humidity 相似文献
15.
Methanobacterium thermoautotrophicum was grown in continuous culture in a fermenter gassed with H2 and CO2 as sole carbon and energy sources, and in a medium which contained either NH4Cl or gaseous N2 as nitrogen source. Growth was possible with N2. Steady states were obtained at various gas flow rates with NH4Cl and with
and the maintenance coefficient varied with the gas input and with the nitrogen source. Growth of Methanococcus thermolithotrophicus in continuous culture in a fermenter gassed with H2, CO2 as nitrogen, carbon and energy sources was also examined.Abbreviations
molecular growth yield (g dry weight of cells per mol of CH4 evolved)
-
growth rate (h-1)
-
D
dilution rate (h-1)
- rate (h-1);
relation of Neijssel and Tempest and of Stouthamer and Bettenhaussen
-
energy 相似文献
16.
The growth yield of Chlorella vulgaris, Y
kJ defined as g cells harvested per kJ of light energy absorbed by the cells, was assessed in a turbidostat culture by varying CO2 and O2 partial pressures (
and
). The value of Y
kJ ranged from 3.1×10-3 to 5.0×10-3 g cells/kJ under light-limited conditions [
= 1.02.4%,
= 065%; total pressure of gas (composed of CO2, O2 and N2)=1 atm]. In the light-limited environment, the algal specific growth rate deteriorated appreciably with the increase of
. The deterioration accounts for the above range of Y
kJ observed. The growth inhibition due to oxygen that was defined by subtracting from 1.0 the ratio of at given values of
to that at
= 0% extended from 0.07–0.30 (7–30%). However, glycolate could not be detected in the turbidostat culture. Isotopic experiments on the specific rate of 14CO2 uptake also revealed that the inhibition due to oxygen was from 22–38% when
was varied from 0 to nearly 100%. These effects of oxygen were discussed, referring to the activity of ribulose-1,5-bisphosphate carboxylase that is inhibited competitively by oxygen.Non-Standard Abbreviations INH
isonicotinic acid hydrazide
- PPO
2,5-diphenyloxazole
- DCMU
3-(-3,4-dichlorophenyl)-1,1-dimetylurea
- CA
carbonic anhydrase
- RuP2
ribulose-1,5-bisphosphate 相似文献
17.
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
18.
Veronique Billat Jean C. Renoux Jacques Pinoteau Bernard Petit Jean P. Koralsztein 《European journal of applied physiology and occupational physiology》1994,69(3):271-273
The aim of this study was to measure running times to exhaustion (Tlim) on a treadmill at 100% of the minimum velocity which elicits
max
max in 38 elite male long - distance runners
max = 71.4 ± 5.5 ml.kg–1.min–1 and
max = 21.8 ± 1.2 km.h–1). The lactate threshold (LT) was defined as a starting point of accelerated lactate accumulation around 4 mM and was expressed in
max. Tlim value was negatively correlated with
max (r = -0.362, p< 0.05) and
max (r = –0.347, p< 0.05) but positively with LT (%v
max) (r = 0.378, p < 0.05). These data demonstrate that running time to exhaustion at
max in a homogeneous group of elite male long-distance runners was inversely related to
max and experimentally illustrates the model of Monod and Scherrer regarding the time limit-velocity relationship adapted from local exercise for running by Hughson et al. (1984) . 相似文献
19.
D. B. Sattelle K. H. Langley A. L. Obaid B. M. Salzberg 《European biophysics journal : EBJ》1987,15(2):71-76
Quasi-elastic laser light scattering has been used to investigate the size and dispersity of synaptosomes and synaptic vesicles isolated from optic lobes of the squid Loligo pealei. Synaptosomal fractions were highly polydisperse (
) and the mean diameter (
) ranged from 0.5–2.0 m. Size distribution histograms yielded two major components — smaller particles (
) and a larger group of particles (
). The heterogeneity of the synaptosomal particles detected in solution is in agreement with published data obtained using electron microscopy. Purified synaptic vesicle fractions also yielded complex particle size distribution data. A component with a mean diameter in the range 150–250 nm was detected, though a smaller particle (
) dominated the scattering signal. This smaller particle closely resembles in size the electron lucent vesicles seen in the majority of squid optic lobe nerve terminals when examined by electron microscopy. Osmotically-induced shirnkage and swelling of the synptosomes was detected. Depolarization by veratridine (1.0×10–4
M) did not result in a detectable change in the size of synaptosomal particles. 相似文献
20.
The natural abundance hydrogen-isotope composition of leaf water (
) and leaf organic matter (
D
org
) was measured in leaves of C3 and C4 dicotyledons and monocotyledons. The
value of leaf water showed a marked diurnal variation, greatest enrichment being observed about midday. However, this variation was greater in the more slowly transpiring C4 plants than in C3 plants under comparable environmental conditions. A model based on analogies with a constant feed pan of evaporating water was developed and the difference between C3 and C4 plants expressed in terms of either differences in kinetic enrichment or different leaf morphology. Microclimatic and morphological features of the leaves which may be associated with this factor are discussed. There was no daily excursion in the
D
org
value in leaves of either C3 or C4 plants. When
D
org
values were referenced to the mean
values during the period of active photosynthesis, the discrimination against deuterium during photosynthetic metabolism (D) was greater in C3 plants (-117 to -121) than in C4 plants (-86 to -109).These results show that the different water use strategies of C3 and C4 plants are responsible for the measured difference in deuterium-isotope composition of leaf water. However, it is unlikely that these physical processes account fully for the differences in hydrogen-isotope composition of the products of C3 and C4 photosynthetic metabolism.Symbols
Hydrogen-isotope composition of leaf water
-
D
org
hydrogen-isotope composition of leaf organic matter 相似文献