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At least 1,099 records · Page 61Linked to original sources
PubMed1976

The effect of noradrenaline and 5-hydroxytryptamine injected into a lateral cerebral ventricle, on thermoregulation in the new-born lamb.

1. Respiratory frequency, shivering, ear skin temperatures and rectal temperatures were observed following intraventricular injections of noradrenaline (NA), 5-hydroxytryptamine (5-HT) and saline (NaCl) into new-born lambs exposed to ambient temperatures of 4, 21, or 30 degrees C. 2. Intraventricular NA caused respiratory rate to decrease and body temperature to increase in the 30 degrees C environment. At 21 degrees C, it increased ear skin temperature but did not significantly affect rectal temperature. At 4 degrees C, NA decreased shivering and rectal temperature fell. 3. 5-HT elevated respiratory rate in the 30 degrees C environment and increased ear skin temperature in the 21 and 4 degrees C environments. In the 4 degrees C environment rectal temperature decreased. 4. In general, the change in rectal temperature was related to the dosage of drug administered. Control injections of NaCl had no significant effect on any of the variables measured. 5. The monoaminergic pathways involved in thermoregulation in the new-born lamb appear to be organized in a manner similar to that of the adult sheep and are functional at birth.

Animals↗
PubMed1998

A temperature cline in copy number for 412 but not roo/B104 retrotransposons in populations of Drosophila simulans.

The copy number of the retrotransposable element 412 of Drosophila simulans from populations collected worldwide shows a negative correlation with minimum temperature. No association was detected for the roo/B104 element. The possibility that selective pressures might regulate the 412 copy number in these natural populations is supported by detection of selection against the detrimental effects of 412 insertions (estimated by the proportion of insertions on the X chromosome in comparison with the autosomes) but not roo/B104. These data reveal different spatial patterns for two element families, and strongly suggest that some factors in the environment, such as temperature, may interfere with the control of retrotransposition, thus affecting important aspects of genomic evolution.

Animals↗
PubMed1989

Tryptophan environments in glutathione transferase of human placenta from temperature-dependent phosphorescence studies.

An investigation of the tryptophan emission properties of glutathione transferase from human placenta was conducted in order to characterize the environments of the two aromatic residues. The low-temperature phosphorescence spectra and temperature dependence of the phosphorescence quantum yield of the tryptophan residues revealed a difference in the chemical nature and dynamical structure of the surrounding protein matrix. Thus, one tryptophan residue seems to be deeply embedded within the polypeptide in a rigid weakly polar environment, characteristic of a beta-type secondary structure. The other is located in a more polar site, probably near the surface, in a rather flexible region of the macromolecule. At high temperature, the heterogeneity in the triplet lifetime of the internal residue attests to the presence of multiple conformers which are not in rapid equilibrium in the phosphorescence time scale. The anisotropy of the phosphorescence emission of glutathione transferase indicates that no energy transfer occurs between the two residues, and measurement of the rotational correlation time yields an hydrodynamic volume which is in good agreement with the molecular weight reported in the literature for the dimer.

Female↗
PubMed2004

Effect of temperature on the survival and infectivity of Pseudotheraptus devastans vector.

The aim of this study was to investigate under a controlled environment, the effect of temperature on the survival and infectivity of Pseudotheraptus devastans Distant, a cassava anthracnose disease vector. The insect P. devastans was collected from young cassava (Manihot esculenta Crantz) field plots, at the International Institute of Tropical Agriculture, (IITA), Ibadan, Nigeria. A mixture of the different developmental stages of eggs, first to fifth instar nymphs, and adults, were incubated in controlled environment chambers, under various constant temperatures of: 15, 17, 22, 25, 27, 30, and 35 degrees C. Relative humidity at different temperature conditions were recorded and maintained at 90%, 85%, 80%, 75%, 70%, 65%, and 60%, respectively. A significant increase in insect survival was observed between 22 and 27 degrees C temperature conditions while a significant decrease in survival was observed at 15 degrees C and above 30 degrees C. Lesion number, lesion diameter and infectivity among the insect stages varied as a function of temperature and relative humidity. Infectivity was highest at 22-25 degrees C maintained at 75-80% RH and lowest at 15 degrees C and above 30 degrees C maintained respectively, at 65% RH and 90% RH. There was considerable low vector infectivity due to low survival of the insects at extreme temperatures.

Animals↗
PubMed2002

Factors influencing the precision of estimating the postmortem interval using the triple-exponential formulae (TEF). Part II. A study of the effect of body temperature at the moment of death on the postmortem brain, liver and rectal cooling in 117 forensic cases.

The temperatures of three body sites, namely, the brain, liver and the rectum as well as the temperature of the environment were continuously monitored, every 5-10 min, in 117 forensic cases commencing soon after death and in most cases, within 45 min postmortem. The body temperature at the moment of death was empirically determined by a computer-based extrapolation method. Thus, temperature data for the first 3h of each body site were fitted to single-exponential equations and the fitted curve was extrapolated backwards to obtain the intercept on the Y-axis (the temperature axis). The effect of body temperature at the moment of death on postmortem cooling rate is examined and factors influencing body temperature at death are discussed. Forensic fatalities associated with hyper and hypothermia are reviewed briefly.

Bedding and Linens↗
PubMed2005

A thermoregulatory center in hornets: IR photography.

In the Oriental hornet Vespa orientalis (Hymenoptera, Vespinae), there is on the dorsal side of the thorax, beneath the mesoscutum plate of the prothorax and around the median notal suture, a lump that, in the course of hornet activity, is warmer by 9 degrees C from the surrounding milieu and by up to 6 degrees C from other body parts of the hornet. This lump is about 1 mm in diameter, butterfly-shaped, and its upper, posterior border abuts the base of the forewings. During hornet activity and via Infra Red photography one can observe heat extensions stemming from the center of the lump and proceeding forward in the direction of the head, downward toward the legs and backwards toward the bases of the wings. The warmest region is the center of the lump, with its margins showing a lower temperature. As for the legs of the hornet, their upper part is warmer than the other parts. The temperature gradients along the hornet's body are dependent on the extent and nature of hornet activity. Thus, during flight or ventilation activity, the thorax is the warmest part of the body, while the wings, legs, and antennae, as well as the posterior part of the gaster are colder, yet all these body parts are still warmer to varying degrees than the surrounding milieu. Thus, at night, when sentry worker hornets stand guard around the nest entrance and remain practically motionless, the temperature differences between the various body parts are retained unchanged. We conjecture that the described butterfly-shaped lump is a thermoregulatory center (TC), which is neurogenically activated, since the changes occurring in it are rapid, a matter of one to several seconds and do not appear to be directly dependent on the hemolymph supply. The thermoregulatory center keeps a high constant temperature apparently related to hornet activity and the environmental conditions. The temperature cascade is most probably regulated via the tracheal system. Apparently another system activated by a heat pump mechanism keeps the gaster at a lower temperature than the environment.

Animals↗
PubMed2002

Effects of temperature on the sensitivity of sludge worm Tubifex tubifex Müller to selected heavy metals.

The present study evaluates the effect of temperature on the sensitivity of the freshwater tubificid sludge worm Tubifex tubifex Müller to 10 heavy metal ions. Metals used in this study were cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, and zinc. The acute toxicity of these heavy metals was studied at 15, 20, 25, and 30 degrees C. The percentage mortality, relative toxicity, and EC50 values and their 95% confidence limits from 24 to 96 h were determined at varying temperatures. The EC50 values (mg/liter) of metal ions at 15 degrees C were Hg2+, 0.034; Cu2+, 0.340; Cr6+, 1.846; Zn2+, 10.99; Ni2+, 25.10; Cd2+, 56; Fe3+, 86.09; Co2+, 239.39; Pb2+, 456.76; and Mn2+, 164.55. At 30 degrees C the values were Hg2+, 0.014; Cu2+, 0.031; Cr6+, 0.872; Zn2+, 3.37; Ni2+, 18; Cd2+, 28.55; Fe3+, 71.26; Co2+, 95.35; Pb2+, 165.22; and Mn2+, 239.39. The results indicate that the acute toxicity of cadmium, chromium, cobalt, copper, lead, mercury, nickel, and zinc increases with temperature increase. The toxicity of manganese was not influenced by temperature, and temperature had little effect on iron toxicity. The rank order of toxicity of metal ions at 15, 20, 25, and 30 degrees C is presented and discussed. It is concluded that temperature is an important factor in short-term acute toxicity tests. The study indicates that seasonal temperature changes are an important variable in determining the amount of heavy metals that may be safely released from metal industries and other similar sources into the aquatic environment. Influence of temperature on the short- and long-term toxicity of chemicals should be considered for establishing appropriate water-quality criteria and standards to protect aquatic flora and fauna and human health.

Adaptation, Physiological↗