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At least 469 records · Page 26Linked to original sources
PubMed1997

Novel smooth muscle cell lines from transgenic mice harboring temperature-sensitive SV40 large T-antigen gene. Temperature-dependent expression of smooth muscle myosin heavy chain-1 and calponin genes.

We have established novel vascular smooth muscle cell lines (SVS30 and SVS24 cells) which retain the expression of specific markers for smooth muscle cells, such as alpha-actin, smooth muscle myosin heavy chain-1, and calponin, from transgenic mice harboring the temperature-sensitive SV40 large T-antigen gene. SVS cell lines showed temperature-dependent growth and the expression of SV40 large T-antigen. Interestingly, protein and mRNA levels of smooth muscle myosin heavy chain-1 and calponin seen in culture at the non-permissive temperature (39 degrees C) were higher than those at the permissive temperature (33 degrees C). These results suggest that SV40 large T-antigen affects the expression of smooth muscle-specific markers in SVS cell lines, and that some of the characters in SVS cell lines can be controlled by culture temperature. SVS cell lines should be quite valuable tools with which to study the regulation of phenotypic modulation of smooth muscle cells, and to identify smooth muscle specific transcription factors which involve the expression of smooth muscle myosin heavy chain-1 and calponin genes.

Animals↗
PubMed1986

Temperature measurements by nuclear magnetic resonance and its possible use as a means of in vivo noninvasive temperature measurement and for hyperthermia treatment assessment.

In the foregoing we have tried to give a broad survey of the parameters which are of importance for irradiation experiments and which can be measured by NMR. Since it is the temperature change during irradiation that is of immediate interest, we have tried to emphasize the ways in which this quantity can be measured. This has shown that temperature measurement by means of the chemical shift has experimental limits as well as the fact that overlapping signals may cause problems. Hence, more experiments must be carried out in order to clarify the possibilities of its use. Although experimentally this is no easy task, it is feasible. In particular, the possibility of determining the temperature by external markers introduced into the tissue should be studied. The development of new nontoxic thermometric compounds with greater sensitivity would be a great step forward. The possibility of determining the temperature through the relaxation times of water represents a real alternative, especially since this can be carried out by low-resolution NMR. Additional experiments are necessary in order to see whether the sensitivity attainable is satisfactory. Chemical exchange processes and changes in metabolite concentration could also be used to measure the temperature or the effect of an irradiation experiment. In conclusion, one can say that the measurement of control parameters (especially for irradiation experiments by means of NMR) represents a difficult experimental problem. It does not promise success in all cases but probably represents the only noninvasive measurement possibility. For this reason, wide-ranging experiments should be initiated in order to obtain definitive results.

Body Temperature↗
PubMed1996

Bilateral skin temperature, handedness, and the biofeedback control of skin temperature.

There are differences in physiological variables when they are recorded from the left and right side of the body simultaneously. In some cases, handedness has been found to have a significant relationship to bilateral differences. The present study examined the relationship between handedness and baseline heart rate and skin temperature, as well as bilateral differences in skin temperature during visual and auditory biofeedback. Subjects were 32 college females, 24 right-handed and 8 left-handed. Recordings of heart rate and skin temperature from both the dominant and the nondominant hand were made during baseline and during the 10-min experimental session while subjects attempted to warm their dominant hand. Both groups showed significantly increased skin temperature during the experimental session. No prominent bilateral differences in skin temperature were found. These results do not support bilateral differences as a generalizable construct.

Adult↗
PubMed1983

An X-ray diffraction study on phase transition temperatures of various membranes isolated from Tetrahymena pyriformis cells grown at different temperatures.

Mitochondrial, microsomal and pellicular membranes were isolated from Tetrahymena cells grown at 39 degrees C or 15 degrees C, and phospholipids, in turn, were separated from total lipids extracted from these membranes. The effect of growth temperature on their solid-to-fluid phase transition temperature was examined by wide-angle X-ray diffraction. The transition temperatures of phospholipids from mitochondria, microsomes and pellicles were 21, 19 and 26 degrees C for cells grown at 39 degrees C and -8, -3 and 6 degrees C for cells grown at 15 degrees C, respectively. All phospholipids were found in a completely fluid state at these growth temperatures. From a comparison between the phospholipids and total lipids from pellicles of cells grown at 39 degrees C, a triterpenoid alcohol, tetrahymanol, caused the transition temperature to increase. The alignment of tetrahymanol in membranes was examined with pellicle'a total lipid oriented in a sample holder.

Cholesterol↗
PubMed1977

Effect of temperature on arginine incorporation by ribosomeless extracts of cells transformed by a temperature-sensitive mutant of Rous sarcoma virus.

The effect of transformation of normal rat kidney cells by a temperature-sensitive mutant of the Prague strain of Rous sarcoma virus (ts LA 24 PR-A) on the post-translational addition of arginine to the NH2-terminus of preformed acceptor molecules has been studied. Cells maintained at the permissive (35 degrees C) temperature show a high arginine-incorporating activity in ribosome free extracts compared to that found in extracts of cells grown at the non-permissive (40 degrees C) temperature. Temperature shift experiments as well as studies with cells transformed by wild type Rous sarcoma virus suggest that the decreased activity in cells grown at 40 degrees C is not due to a high temperature per se. The lower arginine incorporation in the 40 degrees C cell extracts is partially due to a decrease in the activity of arginyl transferase which catalyses the transfer of arginine from arginyl tRNA to the acceptor protein. Polyacrylamide gel electrophoresis of the radioactive product shows that the acceptor molecules present in extracts of cells grown at 40 degrees C are larger and qualitatively different from those found in extracts of cells grown at 35 degrees C.

Acyltransferases↗
PubMed1989

Conformational transition of aquomethemoglobin: intramolecular histidine E7 binding reaction to the heme iron in the temperature range between 220 K and 295 K as seen by EPR and temperature-jump measurements.

Temperature-dependent EPR and temperature-jump measurements have been carried out, in order to examine the high-spin to low-spin transition of aquomethemogobin (pH 6.0). Relaxation rates and equilibrium constants could be determined as a function of temperature. As a reaction mechanism for the high-spin to low-spin transition, the binding of N epsilon of His E7 to the heme iron had been proposed; the same mechanism had been suggested for the ms-effect, found in temperature-jump experiments on aquomethemoglobin. A comparison of the thermodynamic quantities, deduced form the measurements in this paper, gives evidence that indeed the same reaction is investigated in both cases. Our results and most of the findings of earlier studies on the spin-state transitions of aquomethemoglobin, using susceptibility, optical, or EPR measurements, can be explained by the transition of methemoglobin with H2O as ligand (with high-spin state at all temperatures) and methemoglobin with ligand N epsilon of His E7 (with a low-spin ground state). Thermal fluctuations of large amplitude have to be postulated for the reaction to take place, so this reaction may be understood as a probe for the study of protein dynamics.

Animals↗
PubMed2006

Temperature-dependent stress response in oysters, Crassostrea virginica: pollution reduces temperature tolerance in oysters.

Combined effects of temperature and a toxic metal, cadmium (Cd), on energy metabolism were studied in a model marine bivalve, the eastern oyster Crassostrea virginica, acclimated at 20, 24 and 28 degrees C and exposed to 50microgl(-1) of Cd. Both increasing temperature and Cd exposure led to a rise in standard metabolic rates, and combined stressors appeared to override the capability for aerobic energy production resulting in impaired stress tolerance. Oysters exposed to elevated temperature but not Cd showed no significant change in condition, survival rate and lipid peroxidation, whereas those exposed to both Cd and temperature stress suffered high mortality accompanied by low condition index and elevated lipid peroxidation. Furthermore, RNA/DNA ratios indicative of protein synthesis rate, and levels of glutathione, which is involved in metal detoxification, increased in Cd-exposed oysters at 20 degrees C but not at 28 degrees C. Implications of the synergism between elevated temperatures and cadmium stress on energy metabolism of oysters are discussed in the light of the potential effects of climate change on oyster populations in polluted areas.

Animals↗
PubMed2004

Monitoring effective column temperature by using shape selectivity and hydrophobicity and the effects of mobile phase temperature.

Relative changes in the hydrophobicity and shape selectivity of standard analytes are shown to be a valuable method to monitor the reproducibility of the effective temperature experienced by the analytes in a chromatographic column in different ovens. Significant differences were observed between ovens with the same nominal temperature and could be a major cause of problems encountered in transferring methods between instruments or laboratories. By using two parameters, changes due to the column temperature can be distinguished from those caused by mobile phase composition differences. In addition marked increases in column efficiency were noted as the mobile phase temperature was reduced below the column temperature in contrast to claims that thermal equilibration is essential.

Chromatography, Liquid↗
PubMed2004

When body temperature changes, does rectal temperature lag?

By using temporal artery and rectal thermometers, we followed temperatures in 45 febrile (>38.5 degrees C) infants given an antipyretic drug. Sixty and 90 minutes after drug administration, temporal artery temperatures had decreased significantly more than rectal temperatures. When body arterial temperature changes rapidly, changes in rectal temperature may lag.

Analgesics, Non-Narcotic↗
PubMed2006

A T7-expression system under temperature control could create temperature-sensitive phenotype of target gene in Escherichia coli.

Temperature-sensitive (TS) mutants of a gene are ones of which the activity or phenotype is very similar to that of wild type only at certain temperature and they provide extremely powerful tool for studying protein function in vivo. Here we report a novel strategy to generate TS phenotype of the interest gene in Escherichia coli based on a temperature-sensitive T7-expression system. A TS T7-RNA polymerase is generated by interrupting it with a TS intein from Saccharomyces cerevisiae vacuolar ATPase subunit (VMA), resulting that the gene flanked by T7-promoter and T7-terminator will be transcribed only at the permissive temperature (18 degrees C), not at the restrictive temperature (37 degrees C). The feasibility to create TS phenotype of this strategy was detected using lacZ as target. Reverse transcriptase polymerase chain reaction (PCR) indicated that at 18 degrees C, transcripts of T7-promoter controlled lacZ were at least 85 times more than those at 37 degrees C. Western blot analysis and enzymatic assay showed that large amounts of active His6-tagged LacZ produced at 18 degrees C but little at 37 degrees C. This strategy appears more promising than other TS creation methods because the target is pre-designed, no modification is introduced, and only simple DNA manipulation is required.

DNA-Directed RNA Polymerases↗
PubMed1985

The use of voided urine temperature in the determination of basal body temperature.

The temperature of freshly voided urine has been shown to be a reliable predictor of body temperature. This relationship was confirmed for the measurement of BBT. A method was described for patients to obtain their BBT in a way that they may find more convenient than obtaining either oral or rectal temperature. The BBT graph patterns generated from the temperature of freshly voided urine closely paralleled those generated by oral temperature.

Body Temperature↗
PubMed2000

High temperature and temperature programming in capillary electrochromatography.

In electrochromatography, solvent electrophoretic mobility and solute partitioning are temperature dependent processes. If temperature variations are controlled, solute selectivity and analysis times can be tailored. In this study the feasibility of temperature programming in capillary electrochromatography (CEC) was demonstrated using a reversed-phase CEC mode. The outcome of programmed separations was compared with isothermal, isocratic and isorheic (constant flow) separations. The combined effects of column temperature and mobile phase flow-rate changes during the separation run, resulted in up to a 50% reduction in the separation run time, without adversely affecting the quality of separation. For capillary electrochromatography, temperature programming may be a valuable alternative to solvent programming modes because of the great technical difficulties associated with carrying out solvent gradient elution.

Electrophoresis, Capillary↗
PubMed2003

Rapid responses to high temperature and desiccation but not to low temperature in the freeze tolerant sub-Antarctic caterpillar Pringleophaga marioni (Lepidoptera, Tineidae).

A broad definition of rapid cold hardening (RCH) is that it is the process whereby insects increase their survival of a sub-zero temperature after a brief (h) pre-exposure to a less severe low temperature. The effects of various pre-treatments on survival of two h at -7.9 degrees C were investigated in the freeze tolerant sub-Antarctic caterpillar Pringleophaga marioni (Lepidoptera: Tineidae), the first time RCH has been investigated in a freeze tolerant arthropod. All caterpillars froze when exposed to -7.9 degrees C, and none of the low temperature pre-treatments (-5, 0, 5 and 15 degrees C, as well as -5 degrees C and 0 degrees C with a delay before freezing) nor slow cooling (0.1 degrees C/min) elicited any improvement in survival of -7.9 degrees C as compared to controls. However, high temperature treatments (25, 30 and 35 degrees C), desiccation and acclimation for 5 days at 0 degrees C did result in significant increases in survival of the test temperature, possibly as a result of heat shock protein production. Haemolymph osmolality was elevated only by the 35 degrees C pre-treatment. It is suggested that the unpredictable environment of Marion Island means that P. marioni must always be physiologically prepared to survive cold snaps, and that this year-round cold hardiness therefore supersedes a rapid cold hardening response.

Acclimatization↗
PubMed2002

Response surface models to predict potato tuber infection by Fusarium sambucinum from duration of wetness and temperature, and dry rot lesion expansion from storage time and temperature.

Dry rot (Fusarium sambucinum) of potatoes causes significant yield loss in storage and may also produce mycotoxins. Disease dynamics of dry rot development in potato tubers after harvest was studied and modeled. Potato tubers were surface sterilized, wounded, inoculated with a spore suspension of F. sambucinum and incubated in mist chambers placed in growth chambers at 4, 8, 12, 16 or 20 degrees C. After 0, 3, 6, 12, 24 and 48 h of incubation five tubers from each treatment were removed, dried and stored at 16 degrees C and 95% RH for 15 days. Inoculated tubers were also maintained in mist chambers for 24 h at 16 degrees C for the establishment of initial infections, dried, and stored at 4, 8, 12, or 16 degrees C for up to 90 days at 95% RH. At 15 days intervals, tubers were sliced, diameters and depths of diseased area measured, and data transformed to proportion of maximum volume diseased (PVD). The amount of infection was least at the lowest temperature tested and at the end of a 3-h wet period, but infection increased with an increase in wetness duration and temperature. At a storage temperature of 16 degrees C, lesions expanded rapidly reaching maxima in about 45 days of storage. A cubic regression model to predict infection potential from incubation temperature and duration of wetness explained 94.2% of the variation in PVD. A cubic regression model to predict lesion expansion potential as a function of storage temperature and duration explained 99.7% of the variation in PVD. These models could be used to manage potato dry rot, after validation under commercial conditions.

Food Contamination↗
PubMed2003

Conserved temperature-dependent expression of RNA-binding proteins in cyanobacteria with different temperature optima.

The expression of the rbp genes, which encode small RNA-binding proteins with a single RNA-recognition motif, is known to increase at low temperature in Anabaena variabilis M3. The 5'-untranslated region (UTR) of the rbpA1 gene is involved in the cold-regulation. We compared the regulation of the rbp genes in three strains of cyanobacteria having different temperature optima, namely, a mesophilic strain Anabaena sp. PCC 7120, a thermophilic strain Thermosynechococcus elongatus BP-1, and a psychrophilic Antarctic strain Oscillatoria sp. SU1. In Anabaena 7120 and T. elongatus, all the rbp gene sequences are known, and the 5'-UTR sequences of some rbp genes have a high similarity to the 5'-UTR of rbpA1. We found that transcripts as well as protein products of these rbp genes accumulated at low temperature. In addition, the expression of rbp genes increased at low temperature in the Oscillatoria sp. SU1. This suggests that a mechanism of cold-regulation of rbp genes is common among various species of cyanobacteria that belong to different taxa and have different temperature optima.

5' Untranslated Regions↗
PubMed1983

Ornithine decarboxylase activity in embryos depends on temperature of development rather than on the stage of development. Molecular adaptation to temperature changes in poikilothermic animals.

The activity of ornithine decarboxylase (ODC) (the key enzyme of polyamine synthesis) in different poikilothermic animals depends on the temperatures at which they were kept just before the enzyme assay. With an increase in temperature (within physiological limits) ODC activity rises 5-25-fold within several hours. With a decrease in temperature it falls at the same rate. This effect, studied on loach (Misgurnus fossilis) embryos in detail, was also shown for embryos, larvae and some adult tissues of many species. It is not, however, observed in homoiothermic animals (chick embryos and mammalian cells), nor in bacteria and plants. Changes in polyamine concentrations follow those in ODC activity, but more slowly and to a lesser extent. It is assumed that modulation of ODC activity changes as a result of its synthesis and degradation. We suggest that the temperature-dependence of ODC activity is a mechanism of adaptation which maintains the optimal cellular concentration of polyamines for each temperature.

Adaptation, Physiological↗
PubMed2003

The DNA-binding activity of an AP2 transcriptional activator HvCBF2 involved in regulation of low-temperature responsive genes in barley is modulated by temperature.

An HvCBF2 cDNA was isolated from barley leaves. It encoded a protein containing an AP2 DNA-binding domain homologous to C-repeat (CRT)/dehydration-responsive element (DRE) binding factors (CBF/DREB1). In contrast to the previously reported cold-inducible CBF/DREB1 genes, HvCBF2 was expressed in barley leaves under non-stress conditions. Only a transient increase in the HvCBF2 transcript level was observed during cold treatment. Transactivation analysis showed that HvCBF2 was a transcriptional activator, capable of activating expression of a reporter gene driven by a low-temperature and drought-responsive HVA1s promoter in barley leaves. The activity of HvCBF2 as a transcriptional activator was upregulated by low temperature. DNA-binding analysis revealed that HvCBF2 did not bind to the CRT/DRE motif at 30 degrees C. A low, but detectable, binding activity was observed at 25 degrees C and the binding activity gradually increased as the temperature decreased. The binding activity at 0 degrees C was the highest and more than 10 times higher than that at 25 degrees C. The activation and inactivation of HvCBF2 activity were reversible and were achieved in a cell-free system simply by temperature change. Analysis of the binding sequence showed that HvCBF2 bound to a (G/a)(T/c)CGAC core motif, where the lower-case letters are less efficient bases. These data suggest that HvCBF2 is a transcription factor interacting with the core CRT/DRE motif containing a preferred sequence of GTCGAC and its DNA-binding activity is regulated by temperature. This represents a new type of activation mechanism for transcriptional activators.

Amino Acid Sequence↗
PubMed1992

Low-temperature storage of bone marrow in nitrogen vapor-phase refrigerators: decreased temperature gradients with an aluminum racking system.

Large temperature gradients may exist in nitrogen vapor-phase refrigerators. Cryopreserved cells stored at higher levels may be considerably warmer than those stored closer to the liquid nitrogen reservoir. To decrease this temperature gradient, racking systems constructed of aluminum were placed in marrow storage refrigerators. The higher heat conductivity of aluminum resulted in a vapor-phase temperature gradient of only 5.9 degrees C at 22.5 inches above the liquid, as compared to the gradient of 86 degrees C seen with steel frames in a similar refrigerator. Temperature fluxes were minimal with lid opening or nitrogen filling. The thicker frame size and loss of the lowest storage level resulted in a storage capacity 63 percent of that achievable with steel frames and liquid immersion. Consumption of nitrogen was estimated to be 174 to 220 percent of the static usage in this model of refrigerator with 6 inches of nitrogen, but comparable to the consumption expected with full immersion of the racking system, regardless of frame construction. These data demonstrate the feasibility of achieving very low, stable, cryogenic temperatures in a vapor-phase refrigerator.

Aluminum↗