Author Keywords: Epididymis; smooth muscle; electrical activity; temperature; Q10 相似文献
1. 1.|Regional differences in the frequency of electrical activity in rat epididymis were maintained at all temperatures below 39°C.
2. 2.|The change in frequency per deg C increased with temperature and was highest in the temperature region of 34–39°C and the Arrhenius plots of the frequency were linear and parallel in all parts of the epididymis.
3. 3.|The Q10 of the frequency varied between 2.2.–4.3.
4. 4.|The conduction velocity at the cauda epididymis was highest (2.8 mm/s) at 37°C. The Q10 of the conduction velocity was 2.3 in the temperature region of 24–37°C.
1. 1.|The turtle Mauremys caspica cools significantly faster than it heats in air. The heating/cooling ratio is 0.49.
2. 2.|The variation of body temperature in relation to time-course in response to a step-function change of environmental temperature, fitted to a second-order system improves that of a first-order system.
3. 3.|The gradient between ambient temperature (Ta) and equilibrium body temperature (Tb) increases significantly and progressively when ambient temperature rises over 25°C.
4. 4.|At 40°C thermoregulatory hyperventilation was detected, implying an increase in air convection requirement (ventilation relative to O2 consumption, ).
Author Keywords: Turtles; heating and cooling rates; thermoregulation; ventilation; Mauremys caspica; reptile 相似文献
1. 1.|Dinitrophenol (DNP) was administered to rats in two equal dosages (20 mg/kg, 30 min interval); the second injection was followed immediately by exercise (9.14 m/min) in the heat (30°C) or at room temperature (21°C).
2. 2.|At 21°C control (saline-treated) rats manifested a mean endurance of 94 min which was reduced to 32 min among DNP-treated animals.
3. 3.|At 30°C, control rats ran for 65 min (δTre/min = 0.05°C) while DNP-treated animals had a mean endurance of only 12 min (δTre/min = 0.22°C).
4. 4.|DNP-treated rats (30°C) manifested no decrements in tail-skin heat loss (δTsk/min = 0.17°C vs 0.10°C) or saliva secretion (0.78 g/min, DNP vs. 0.19 g/min, control) for their brief treadmill duration.
5. 5.|The increased metabolic heat production of DNP severely reduced performance.
Author Keywords: Dinitrophenol; exercise; heat stress; endurnace; temperature regulation 相似文献
1. 1.|The development times and reproduction were measured for Daphnia pulex and Daphnia magna from 5 to 30°C at 5°C increments.
2. 2.|The general trends for D. pulex and D. magna were for the duration of all juvenile instars to be less than that of adults and for the last juvenile (or adolescent) instar to be longer than all previous juvenile instars.
3. 3.|The number of juvenile instars both species pass through before adulthood is influenced by temperature with increasing numbers occurring at temperature extremes.
4. 4.|Duration of development time decreased over the entire range of increasing temperatures measured for D. pulex but increased for D. magna at 30°C in relation to 25°C.
5. 5.|Quadratic models were less desirable than simple linear logarithmic transformations of the form ln Y = ln a + b ln X for describing the temperature/development relationship.
6. 6.|The greatest young production occurs at 15 and 20°C with significant decreases occurring at temperatures above and below these.
7. 7.|The observed temperature-dependent phenomena an the ecological relationships for the two species are discussed.
Author Keywords: Daphnia; development; reproduction; zooplankton; temperature; thermal; crustacea; cladocera; productivity; stress 相似文献
1. 1.|Body temperatures (Tb) and contaneous evaporative water loss rates (CWL) were measured in tree frogs (Hyla cinerea) and toads (Bufo valliceps) exposed to cyclical ramp changes in water vapor density (WVD) between 7.5 and 9.8 gm−3 (1 cycle h−1 at an air temperature of 27.0°C.
2. 2.|CWL was 3.3 times greater in toads than in tree frogs.
3. 3.|Tb in toads cycled directly with WVd; WVD accounted for 98% of the variation in toad Tb.
4. 4.|Tb in tree frogs was independent of WVD, probably due to changes in skin resistance to water loss.
Author Keywords: Body temperature; evaporative water loss; skin resistance; water vapor density; relative humidity; Anura; Hyla cinerea; Bufo valliceps 相似文献
1. 1.|The jumping behaviour of the Mexican jumping bean (Laspeyresia solitans) is stereotyped and predictable and has the characteristics of behaviour which is under the control of a central programme.
2. 2.|Temperatures above and below about 25°C decrease the length of time that movements occur. The movements stop relatively abruptly and not gradually. The duration of movements is apparently controlled by an internal timer whose duration of operation is influenced by temperature.
3. 3.|The frequency of movements show instantaneous temperature compensation from about 21 to 45°C (Q10 = 1.23), whereas between 15 and 21°C there is a large temperature dependence (Q10 = 21.9).
Author Keywords: Behaviour; insect; Laspeyresia solitans Q10 相似文献
1. 1.|External heat exchangers acting on lower aortal blood temperature were used to dissociate hindleg muscle temperature (Thlm) from general internal temperature (Tint) during short-term exercise of moderate intensity.
2. 2.|In series 1 39°C Thlm was combined with 40.6°C Tint, and in series II 42°C Thlm was combined with 39.8°C Tint.
3. 3.|At constant work rates, the 3°C difference in muscle temperature did not result in significantly different concentrations of muscle metabolites.
4. 4.|It is concluded that high local muscle temperature without general hyperthermia does not influence muscle metabolism during short-term moderate excercise.
Author Keywords: Exercise; body temperature; high energy phosphates; glycogen; lactate 相似文献
1. 1.|Neural activity was recorded in hippocampal slices from noncold-acclimated, cold-acclimated and hibernating hamsters.
2. 2.|Action potentials from a population of hippocampal pyramidal neurons were evoked by stimulating an afferent fiber tract, the Schaffer collaterals. The temperature of the artificial cerebrospinal fluid bathing the slice was varied by controlling the temperature of a water chamber jacketing the recording chamber.
3. 3.|The temperature just below that at which a population spike could be evoked, Tt, was 15.8 ± 0.9°C (mean ± SEM) for noncold-acclimated hamsters, 13.9 ± 0.3°C for cold-acclimated hamsters and 12.3 ± 0.3°C for hibernating hamsters.
4. 4.|These thresholds for evoked activity were significantly different in noncold-acclimated, cold-acclimated and hibernating hamsters, and may reflect acclimation of hippocampal neurons to cold.
Author Keywords: Hibernation; Mesocricetus auratus; hippocampal slice; temperature; CA1 pyramidal cells 相似文献
1. 1.|Larval development and metamorphosis of Achaea junta were prolonged at 22°C, compared to 27, 32 and 35°C.
2. 2.|Overall rates of consumption, assimilation, production and metabolism of the larvae increased with temperature.
3. 3.|Efficiencies of assimilation and conversion of the digested food were significantly altered by life stage and temperature.
4. 4.|About 60% of the pupal energy was transferred to the imago at the tested temperatures.
Author Keywords: Lepidoptera; Noctuidae; Achaea junta; insect; development; bioenergetics; temperature effect; moths 相似文献
1. 1.|The effect of temperature on caecal function was examined in the naked mole-rat Heterocephalus glaber, a poikilothermic mammal, which consumes a high proportion of fibre in its natural diet.
2. 2.|The temperature of optimal caecal function was determined from fermentation data measure at three specifically chosen temperatures (28, 33 and 40°C).
3. 3.|There was no significant difference between gas production at 33 and 40°C, however, gas production was significantly lower at 28°C.
4. 4.|The relative proportions of the gases produced were markedly different at 33 and 40°C (P ≤ 0.01). More methane and hydrogen were produced at 33°C than at 40°C.
5. 5.|These data suggest that microbial organisms within the caecum were active and functioning more effectively at 33°C (the preferred body temperature of the naked mole-rat) than at the other two temperatures.
Author Keywords: Caecal fermentation; temperature effects; gas production; hind gut; naked mole-rat; Heterocephalus glaber 相似文献
1. 1.|The effect of thyroidectomy at 12 days of age on weight gain, and on heat production and thermoregulatory ability of 4- to 5-week-old chickens at temperatures within and below the thermo-neutral zone was investigated.
2. 2.|Despit the absence of thyroid tissue, as demonstrated with radioiodine, a small amount of thyroxine was found in the plasma of some thyroidectomized (TX) birds.
3. 3.|Thyroidectomy depressed weight gain; pair-fed controls grew significantly faster than TX birds.
4. 4.|Resting heat production of TX birds at thermoneutrality (30°C) was depressed by 18% (P < 0.001) and body temperature by 0.4°C (P < 0.001).
5. 5.|At 12°C heat production of TX birds was similar to that of controls but the body temperature of TX birds was 0.7°C lower (P < 0.001).
6. 6.|Thyroidectomized birds were unable to regulate body temperature at 5°C even if thyroxine was provided on the day before and at the time of cold-exposure. This inability to thermoregulate was probably due to inadequate insulation and poor nutritional status.
Author Keywords: Gallus domesticus; thyroidectomy; thyroxine; heat production; thermoregulation; body temperature 相似文献
1. 1.|The metabolic role of the thyroid gland was studied in intact snakes, Naja naja and Ptyas korros treated with tri-iodo-thyronine (T3) and thyroxine (T4) and in thyroidectomized (Tx) N. naja kept at 21°C by analyzing tissue composition and glycogen phosphorylase a activity.
2. 2.|Liver weight was unaffected by thyroid hormone injection in both species but decreases in liver glycogen followed T3 or T4 injection, and there was an increase in liver glycogen in N. naja. These changes in liver glycogen were accompanied by a decrease in glycogen phosphorylase a activity with T3 injection. T3 decreased muscle glycogen in Ptyas and Tx increased it in N. naja.
3. 3.|T3 increased % liver lipid in Ptyas but not in Naja.
4. 4.|Between species, there were differences in liver weight, blood glucose level, cholesterol level and % muscle lipid.
5. 5.|The results showed that thyroid hormones affected carbohydrate and lipid metabolism at a low temperature of 21°C, although the significance is not known.
Author Keywords: Snake, metabolism; liver glycogen and lipid; low temperature; Naja naja; Ptyas korros 相似文献
1. 1.|Alterations in the fatty acid composition of microsomes were most marked in the exponential phase of both 39.5- or 15°C- grown Tetrahymena pyriformis NT-1.
2. 2.|Activities of palmitoyl-CoA and stearoyl-CoA desaturases were lower in 15°C cells than in 39.5°C cells, while the activity of oleoyl-CoA desaturase was higher in 15°C cells.
3. 3.|Activities of the terminal component of the desaturation system as well as all three desaturases (palmitoyl-CoA, stearoyl-CoA, oleoyl-CoA) were higher in the exponential phase than in the stationary phase for cells grown at both temperatures.
4. 4.|NAD(P)H-cytochrome c reductase activity and cytochrome b5 content were reduced whereas NADH-ferricyanide reductase activity was increased in the stationary phase at both 39.5 and 15°C.
Author Keywords: Cyanide sensitive factor (CSF); cell growth in different temperatures; Δ9- and Δ12-desaturases; microsomal electron transport; temperature adaptation; Tetrahymena; protozoa 相似文献
1. 1.|Body temperature preferences were compared between cockroaches acclimated to different ambient temperatures and between 25°C acclimated cockroaches and cockroaches deprived of their peripheral temperature receptors.
2. 2.|Acclimation to 35°C resulted in a significantly higher mean body temperature and low body temperature selected compared with 25°C acclimated cockroaches.
3. 3.|Cockroaches deprived of their peripheral temperature receptors showed a significantly higher mean high body temperature selected when compared to normal 25°C acclimated cockroaches.
4. 4.|It is concluded that cockroach temperature regulation is more precise than expected and that central temperature receptors are the primary sensing elements for cockroach thermoregulation.
Author Keywords: Temperature preference; thermoregulation; Periplaneta americana; peripheral temperature receptors 相似文献
1. 1.|Gemmules of Ephydatia mülleri can withstand exposure to temperatures down to −80°C for 63 days without loss of hatchability.
2. 2.|Hatching is slowed following exposure to temperatures below −27°C.
3. 3.|There is a slight but significant relationship between gemmule size and the time to hatch.
4. 4.|This species can withstand long-term exposure to winter air temperatures occurring within its known geographic range.
Author Keywords: Porifera; Spongillidae; sponge; freshwater sponge; Ephydatia mülleri; gemmule; hatching; low temperature; cold exposure 相似文献
1. 1.|Oxygen consumption ( ) and body temperture (Tb) of Hawaiian brown noddies (Anous stolidus pileatus [Aves: Laridae]) during late incubation and in the first 24 h after hatching were measured at ambient temperatures (Ta) between 28 and 38°C and between 15 and 43°C, respectively. Evaporative cooling by hatchings at Ta of 36–43°C was also measured.
2. 2.|Throughout the late incubation stages studied, and Tb both varied directly with Ta in an ectothermic pattern.
3. 3.|The hatchlings successfully regulated Tb at Ta between ca. 29 and 43°C.
4. 4.|The functional basis of the abrupt increase in thermoregulatory capacity with hatching is discussed.
Author Keywords: Anous stolidus pileatus; bird; late incubation embryos; pipping; hatchlings; metabolic level; development of homeothermy; regulatory thermogenesis; evaporative cooling 相似文献
1. 1.|The difference between tissue temperatures and ambient water temperatures (ΔT) of the ectothermic Arctic charr (Salvelinus alpinus L.) ranged between 0.2 and 0.6°C.
2. 2.|For fish held at 5.7°C there were no significant differences in ΔT of exercising fish and those of controls.
3. 3.|By contrast, for fish held at 1.7°C sustained exercise led to a significant increase in ΔT of all body compartments compared with fish held in standing water (controls).
4. 4.|It is suggested that Arctic charr are capable of a limited control of metabolic heat exchange between body compartments and surrounding water when subjected to sustained exercise and ambient temperatures <2°C.
Author Keywords: Salmonidae; sustained exercise; body temperature; Arctic charr; Salvelinus alpinus 相似文献
1. 1.|In 15 conscious Pekin ducks, 40 “warm sensitive” hypothalamic neurons were identified according to their discharge rates at 40°C Thy (F40), local temperature coefficients (Δ/ΔT) and Q10.
2. 2.|Q10 and either F40 or ΔF/ΔT were little or not related.
3. 3.|A positive correlation between F40 and ΔF/ΔT was observed which was particularly close (r = 0.94 and 0.96) when the neurons were classified according to their Q10 of <2 and >2.
4. 4.|The results suggest that neurons with positive temperature coefficients in the duck's hypothalamus mostly exhibit linear to exponential temperature-discharge relationships.
5. 5.|This is an contrast to observations on mammalian hypothalamic thermosensitive neurons and may relate to the absence of the thermosensory function in the duck's rostral brainstem.
Author Keywords: Neuronal thermosensitivity; hypothalamic thermosensory function; Temperature and synaptic transmission; avian thermoregulation; mammalian thermoregulation 相似文献
1. 1.|The hyperhermia induced haemolysis of cells and resealed ghosts suspended in isotonic NaCl/sucrose media was studied upon transient heating.
2. 2.|At 61.5°C a process of temperature accelerated disturbance of membrane permeability barrier was initiated, wich was sensed by the consequent volume changes. Concomitantly with this process the thermohaemolysis appeared as a threshold colloid-osmotic lysis.
3. 3.|The initial temperature of this successive barrier disturbance was decreased linearly by ethanol. At 18% ethanol this barrier disturbance took place at 39°C while spectrin was denaturated at about 45°C. Apparently, the spectrin denaturation was not sufficient, nor was involved in, the initiation of this membrane disturbance.
4. 4.|The membrane of cells made ion permeable in the presence of 18% ethanol by heating to 39°C contained irreversible pores with a radius of about 0.45 nm.
5. 5.|This suggests a conformational change of a protein(s) in their formation, but not spectrin nor the anion channel.
6. 6.|Using specific amino reagents it was ascertained, that a superficial NH3+ group dissociable at neutral pH impeded this thermo-induced pore formation.
7. 7.|Consistent results show that this formation of membrane pores initiated at 61.5°C may be included in the still unknown mechanism of thermohaemolysis.
Author Keywords: Thermohaemolysis; permeability barrier disturbance; pore formation; colloid-osmotic lysis 相似文献
1. 1.|Goldfish acclimated to a range of temperatures between 5 and 35°C were found to only compensate the specific activity of their myofibrillar ATPase enzyme between 10 and 30°C.
2. 2.|The preferred temperatures of goldfish acclimated to 5°C and to 30°C were determined to be about 10 and 26°C respectively.
3. 3.|It is conlcuded that goldfish are only able to acclimate their myofibrillar ATPase system to temperatures between 10 and 30°C, but acclimation to these temperatures enables them to tolerate extremes.
Author Keywords: Acclimation; myofibrillar ATPase activity; temperature preference; adaption and tolerance limits; goldfish; Carassus auratus 相似文献