Effets de la température d'élevage sur la croissance et l'équilibre hormonal deSchistocerca gregaria au cours des deux derniers stades larvaires

Summary A fall in diurnal rearing temperature (from 33°C to 28°C) during the 2 last larval instars ofSchistocerca gregaria induces a lengthening of development and a slowing down of growth. At 28°C, circulating levels of juvenile hormones, particularly those of JH₃, diminish from the middle of the 4th instar but ecdysteroids and proteins accumulate in haemolymph.     

Photoperiod-induced changes in temperature-metabolism curve,shivering threshold and body temperature in the pigeon

Summary A short photphase combined with cold-acclimation changed the shivering threshold of the pigeon from 21 to 14 °C. The change of critical temperature was also found in the temperature-metabolism curve. A long photophase both alone and combined with warm-acclimation induced a reduction of body temperature to a lower level (about 2°C) at all ambient temperatures, ranging from 5 40°C.     

Effect of temperature on in vitro proliferative activity of human umbilical vein endothelial cells

Human umbilical vein endothelial cells, skin fibroblasts, and retinal pigment epithelial cells are cultivated in medium supplemented with 15 to 20% serum in our laboratory. The effects of various incubation temperatures on the proliferation of these cells was examined. Our study shows that the mitogenic response of the endothelial cells to a change of temperature differed markedly from that of the fibroblasts and epithelial cells. Cultivation of human umbilical vein endothelial at 37°C required seeding densities as high as 1–2×10⁴ cells/cm², and yet resulted in a low growth rate and premature senescence. However, under the same culture conditions, but at 33°C, the proliferative capacity of these endothelial cells was potentiated. The results were striking; at 33°C the cells grew actively and the life span was extended. The number of cumulative population doublings increased fourfold compared with that for the same cells cultivated at 37°C. The inoculum size could be reduced, since at 33°C the endothelial cells were able to replicate at seeding densities as low as 20 cells/cm². The cells serially subcultured at 33°C retained morphological features and specific immunological markers of endothelial cells.     

Effect of water temperature on the motility ofPelagia noctiluca (Forksal)

Summary Laboratory tests have been performed, on the behavior of the jellyfishPelagia noctiluca as a function of the water temperature. It has been found that the usual contractions of the umbrella are almost completely missing at 6°C; they begin to appear at about 7–8°C and they reach frequencies of about 10 and 40 per min at 11 and 15°C respectively. An ambient temperature of about 11°C appears to be a threshold value below which this kind of medusa ceases to move actively and sinks, while at higher temperatures it gradually begins to shift, showing a positive thermotropism in the presence of temperature gradients greater than about 0.01 °C/cm.This work was supported by grant No. 80.00748.88 from the National Research Coucil of Italy (CNR).     

Influence of posttreatment temperature on the toxicity of pyrethroid insecticides to susceptible and resistant larvae of the Egyptian cotton leafworm,Spodoptera littoralis (Boisd.)

Summary The organophosphorus insecticides chlorpyrifos, leptophos, and phosfolan and the carbamate methomyl was found to be more toxic to larvae of a susceptible strain ofSpodoptera littoralis (Boisd.) when the posttreatment temperature was increased from 20 to 35°C. In contrast, the pyrethroids permethrin, fenvalerate, deltamethrin, cypermethrin, and flucythrinate were more toxic at 20°C than at 35°C. This effect was more pronounced in the pyrethroid-resistant strains. Evidently, resistance levels were reduced at low temperature. However, the application of piperonyl butoxide or DEF in combinations with the tested pyrethroids on R-strains resulted in reducing the effect of temperature.     

The growth of Atlantic salmon (Salmo salar L.) myosatellite cells in culture at two different temperatures

Temperature is known to affect fish growth, and in Atlantic salmon there is an influence on muscle cellularity. Primary muscle cell culture makes it possible to investigate direct effects of temperature on myogenic cells. Salmon myosatellite cells were cultured for the first time in this study. The cells were cultured at either 5°C or 11°C. Increased temperature led to an increase in differentiation rate and especially hypertrophic growth (Q₁₀=4.0). No nuclear proliferation was evident in the satellite cell population isolated at either temperature. This may be due to the presence of different subpopulations of myogenic cells at different developmental ages or the presence of indirect factors in vivo.     

Seasonal changes in the critical arousal temperature of the marsupialSminthopsis crassicaudata correlate with the thermal transition in mitochondrial respiration

Summary During periods of torporSminthopsis crassicaudata, a dasyurid marsupial, regulated its body temperature above about 16.3°C in summer and 13.0°C in winter. Animals with lower body temperatures were unable to arouse. Liver, heart and brain mitohondrial succinate:cytochrome c reductase showed a thermal transition at 16°C in summer and at 12.5°C in winter. Thus the lowest regulated body temperature was just above the temperature where changes were detected in mitochondrial respiration.Acknowledgments. This work was supported by a Flinders University Research Scholarship Award to F. Geiser. We thank Prof. J. H. Bennett for the supply of animals and M. O'Driscoll for the animal maintenance.     

Growth ofEchinococcus multilocularis in gerbils exposed to different environmnntal temperature

Summary Gerbils kept at high (35°C) temperature harbored a significantly largerEchinococcus multilocularis cyst biomass than those kept at room (21°C) and low (5°C) temperature. Parasite induced adrenomegaly was observed in all temperature groups.Acknowledgments. I am indebted to Miss Marianne Hardy and Mr Terry Durham for their excellent technical assistance.     

Temperature dependence of neurotransmitter release in the antarctic fishPagothenia borchgrevinki

Summary The quantal contents of endplate potentials from extraocular muscles of an antarctic fishPagothenia borchgrevinki were measured over a range of temperatures. Quantal release was maximal at about 5°C but showed little dependence on temperature between –2°C and 10°C. Above 10°C quantal content declined until release ceased about 18°C. In view of the fact that the ambient temperature at which these fish live is constant at –1.9°C, the results suggest thatPagothenia borchgrevinki is only partially adapted to its environment despite 25 million years acclimatization.The authors wish to thank the staff of New Zealand's Scott Base, Antarctica, without whose cooperation the work would have been impossible. Mr J. Quinn of the Auckland University Physiology Department gave invaluable assistance with computing and electronics and the Antarctic Division of the New Zealand Department of Scientific and Industrial Research provided transportation and logistic support. The project was financially supported by the New Zealand University Grants Committee and the Auckland University Research Committee. S.P. was a Senior Fellow of the N.Z. Medical Research Council.     

Ein Beitrag zur irreversiblen Temperaturinaktivierung der Gewebsatmung

Summary (1) Tissue slices of the liver and pieces of the skin of summer-frogs were incubated at 47.5°C for 30–150 min. Their respiration was measured during this incubation period and thereafter at a temperature of 37.5°C.(2) As a sign of an irreversible inactivation of the enzymes, the average respiration was inhibited. However, after certain periods of incubation at 47.5°C, over-shoot phenomena in the O₂-uptake at the temperature of 37.5°C were seen.     

Haloperidol produces hypothermic effects in rats

Summary Intraperitoneal administration of either haloperidol or chlorpromazine produced hypothermia both in the cold (8° C) and at room temperature (22°C). The hypothermia was brought about both by a decrease in metabolic heat production and an increase in the cutaneous temperature of tail and foot skin. However, at a higher temperature (29°C), there were no changes in rectal temperature and other thermoregulatory responses.The work reported here was supported by grants from the National Science Council of Republic of China and J. Aron Charitable Foundation (New York, N.Y.). The authors are grateful to Dr C.Y. Chai for his advice during the experimentation. The generous support of Dr C.J. Shih was much appreciated by the authors. Also, we thank Dr C.D. Bloomer (Smith, Kline and French Co.) for the supply of chlorpromazine.     

Untersuchungen zur Thermodynamik des peripheren Sehprozesses

Summary In a range from 6 to 30°C, the influence of temperature on the relation between the light intensity and the amplitude of the b-wave of the exposure potential has been investigated for the isolated frog retina. Between 10 and 25°C, the gross activation energy of the response to light leads to a temperature coefficient which shows that the formation of the b-wave is mainly checked by diffusion processes. While at 6°C the b-wave has vanished, a complete delayed off-response can still be registered.     

The effects of temperature on ATPase activity and force generation in skinned muscle fibers from the Pacific blue marlin (Makaira nigricans)

Summary ATPase activity and force generation have been measured simultaneously in isolated, demembranated muscle fibers of the Pacific blue marlin (Makaira nigricans) between 0 and 30°C. Tension generation is relatively independent of temperature above 15°C and falls with a Q₁₀ of <1.5 on decreasing the temperature to 0°C. In contrast, the Q₁₀ for ATPase activity is 2.2 over the range 0–30°C. The results are interpreted in terms of the cross bridge theory of contraction.     

The length of hibernation affects temperature-induced (25°C) spermatogenic multiplication inHelix aspersa Müll

Summary In hibernating snails an increase in temperature from 5°C to 25°C induces DNA synthesis in the gonad but not in the albumen gland and intestine. Spermatogenic multiplication augments in response to increased temperature and this is dependent upon the duration of hibernation.     

Intraventricular administration of isoproterenol inhibits both heat production and heat loss mechanisms in rats

Summary At an ambient temperature (T_a) of 8°C, intraventricular administration of isoproterenol inhibited metabolic heat production and led to hypothermia in rats. In contrast, at a T_a of 22°C and of 30°C, isoproterenol decreased cutaneous circulation and led to hyperthermia. The data indicate that isoproterenol inhibits both heat production and heat loss mechanisms in rats.This work was supported by a grant from the National Science Council of the Republic of China. The authors are grateful to Dr C.Y. Chai for pertinent advice.     

Body temperatures of lambs and their mothers measured by radio-telemetry during parturition

Using temperature-sensitive radio-telemeters chronically implanted in the abdomens of 8 fetal lambs and their mothers, we measured body temperature changes induced by parturition. Maternal body temperature rose at 0.70±0.06 °C/hour (mean±SEM) in the final stages of labour. Fetal body temperature also rose, but at a significantly lower rate, 0.45±0.06 °C/hour (p<0.05). The fetus appears to be protected from excessive hyperthermia during the birth process.     

Effects of photoperiod,temperature and testosterone-treatment on plasma T3 and T4 levels in the Djungarian hamster,Phodopus sungorus

Summary The effects of photoperiod, temperature and testosterone treatment on plasma T₃ and T₄ levels were investigated in the Djungarian hamster. Plasma T₃ level was affected by temperature (25°C<7°C) but not by photoperiod. Plasma T₄ level was affected by photoperiod (short day < long day) at 25°C. Administration of testosterone increased plasma T₄ level under short photoperiod at 25°C. Thus, higher plasma T₄ level under long photoperiod at 25°C might be induced by testosterone.     

Eine neue Bestimmung der Koronatemperatur

Summary The paper deals with a new method to determine the temperature of the solar corona. The method starts from the observational result that the elements found in the corona are distributed over a multitude of consecutive ionisation-stages and leads to the value of 630000° C. Although this method is not an exact one, the result is in good agreement with other methods, leading to a temperature of about 10⁶ ° C.     

Environmental temperature and the growth ofTaenia crassiceps cysticerci in mice

Summary Mice kept at low (5±1 °C) and high (35±1 °C) temperature harboured significantly lessTaenia crassiceps cysticerci than controls kept at 21±1 °C. This effect was more pronounced in heat-stressed than in cold-stressed animals and more in males than in females.     

Stability of ceftizoxime in aqueous solution

Summary Ceftizoxime, when assayed using the disc agar-diffusion method withBacillus subtilis ATCC 6633 as the indicator microorganism in buffered (pH 6) medium, retains its potency in aqueous solution at 4°C for about 3 months. Even after 4 months, some residual activity can be found. However, when this solution was assayed on the non-buffered medium, a seemingly quicker but misleading loss of potency was observed. This resulted from inadequate sensitivity of the assay. The sensitivity of the ceftizoxime assay was increased by lowering the incubation temperature from 37°C to 30°C. The pH- and incubation temperature-dependent potency must be kept in mind when assaying ceftizoxime.