LOW-TEMPERATURE ENVIRONMENTAL STRESS AND THE METABOLISM OF VITAMIN A IN THE RAT

Carotene and vitamin A metabolism in the rat were studied at two environmental temperatures. The utilization of carotene is greater in animals maintained at a low environmental temperature (2°) than at room temperature (22°). This occurred within a period of 3 days. Both the hepatic storage and the rate of metabolism of orally administered vitamin A were unaffected by environmental temperature. The response of Wistar and Sprague–Dawley strains was similar.

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Effects of 7°C environmental temperature acclimation during a 3-week training period

Journal of Applied Physiology ◽

10.1152/japplphysiol.00500.2019 ◽

2020 ◽

Vol 128 (4) ◽

pp. 768-777

Author(s):

Robert Shute ◽

Katherine Marshall ◽

Megan Opichka ◽

Halee Schnitzler ◽

Brent Ruby ◽

...

Keyword(s):

Room Temperature ◽

Environmental Temperature ◽

Cellular Signaling ◽

Temperature Acclimation ◽

Peroxisome Proliferator ◽

Peroxisome Proliferator Activated Receptor ◽

Training Adaptations ◽

Before And After ◽

The Impact ◽

Environmental Temperatures

Cold environmental temperatures during exercise and recovery alter the acute response to cellular signaling and training adaptations. Approximately 3 wk is required for cold temperature acclimation to occur. To determine the impact of cold environmental temperature on training adaptations, fitness measurements, and aerobic performance, two groups of 12 untrained male subjects completed 1 h of cycling in 16 temperature acclimation sessions in either a 7°C or 20°C environmental temperature. Fitness assessments before and after acclimation occurred at standard room temperature. Muscle biopsies were taken from the vastus lateralis muscle before and after training to assess molecular markers related to mitochondrial development. Peroxisome proliferator-activated receptor-γ coactivator 1α ( PGC-1α) mRNA was higher in 7°C than in 20°C in response to acute exercise before training ( P = 0.012) but not after training ( P = 0.813). PGC-1α mRNA was lower after training ( P < 0.001). BNIP3 was lower after training in the 7°C than in the 20°C group ( P = 0.017) but not before training ( P = 0.549). No other differences occurred between temperature groups in VEGF, ERRα, NRF1, NRF2, TFAM, PINK1, Parkin, or BNIP3L mRNAs ( P > 0.05). PGC-1α protein and mtDNA were not different before training, after training, or between temperatures ( P > 0.05). Cycling power increased during the daily training ( P < 0.001) but was not different between temperatures ( P = 0.169). V̇o2peak increased with training ( P < 0.001) but was not different between temperature groups ( P = 0.460). These data indicate that a 3-wk period of acclimation/training in cold environmental temperatures alters PGC-1α gene expression acutely but this difference is not manifested in a greater increase in V̇o2peak and is dissipated as acclimation takes place. NEW & NOTEWORTHY This study examines the adaptive response of cellular signaling during exercise in cold environmental temperatures. We demonstrate that peroxisome proliferator-activated receptor-γ coactivator 1α mRNA is different between cold and room temperature environments before training but after training this difference no longer exists. This initial difference in transcriptional response between temperatures does not lead to differences in performance measures or increases in protein or mitochondria.

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The effect of environmental temperature on prandial changes in leucocyte sodium transport in man

British Journal Of Nutrition ◽

10.1079/bjn19890064 ◽

1989 ◽

Vol 62 (3) ◽

pp. 639-645 ◽

Cited By ~ 3

Author(s):

L. L. Ng ◽

T. D. R. Hockaday

Keyword(s):

Sodium Transport ◽

Room Temperature ◽

Environmental Temperature ◽

Normal Subjects ◽

Efflux Rate ◽

Intracellular Electrolytes ◽

Daily Energy ◽

Na Efflux ◽

Efflux Rate Constant ◽

Environmental Temperatures

Cellular sodium transport via the Na+, K+-ATPase contributes significantly to daily energy expenditure. The effect of a meal on leucocyte Na+ transport and intracellular electrolytes was therefore investigated in lean normal subjects at room temperatures of 23° and 33°, to determine if the Na pump responds to the need for thermogenesis. In the fasting state, the ouabain-sensitive efflux rate which reflects active Na+ transport, and the intracellular electrolytes were similar. At 2 h after eating a 4·2 MJ (1000 kcal) meal, the ouabain-sensitive efflux rate constant rose when the room temperature was 23° but not at 33°. The ouabain-sensitive Na+ efflux rate, an index of active Na+ transport, 0rose post-prandially at 23° only. The post-prandial activation of leucocyte active Na efflux in normal subjects was blunted at higher environmental temperatures, when the need for thermogenesis was reduced.

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Technological synthesis

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1990.0039 ◽

1990 ◽

Vol 326 (1237) ◽

pp. 687-692 ◽

Cited By ~ 3

Keyword(s):

Low Temperature ◽

Environmental Stress ◽

Minimum Temperature ◽

Biological Material ◽

Freezing Injury ◽

Crop Loss ◽

Field Crops ◽

Environmental Temperatures ◽

Reduced Temperature ◽

Separate Discipline

In agriculture and horticulture, chilling and freezing injury of plants often results in serious problems of reduced yield and crop loss. The geographical distribution of many field crops is, in many instances, determined by the minimum temperature encountered. If crop responses to reduced temperature could be modified major changes in productivity would result. In addition to the studies of the effects of environmental temperatures, a separate discipline has arisen in low-temperature biology concerned with the extended storage of viable biological material, generally at the temperature of liquid nitrogen. Until recently, there has been little dialogue between the disciplines of environmental studies and cryopreservation. It is probable that an understanding of the tolerance of organisms to environmental stress would accelerate progress in cryopreservation.

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RELATION OF OXYGEN UPTAKE TO BODY WEIGHT OF RATS AT DIFFERENT ENVIRONMENTAL TEMPERATURES

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y65-035 ◽

1965 ◽

Vol 43 (3) ◽

pp. 351-357 ◽

Cited By ~ 2

Author(s):

N. T. Gridgeman ◽

O. Heroux

Keyword(s):

Body Weight ◽

Oxygen Consumption ◽

Statistical Analysis ◽

Oxygen Uptake ◽

Linear Relation ◽

Environmental Temperature ◽

Analysis Of Covariance ◽

Sprague Dawley ◽

Experimental Conditions ◽

Environmental Temperatures

Statistical analysis of data on the oxygen consumption of rats (Sprague–Dawley strain; records covering several years of experimentation in one laboratory) indicated that the relation between oxygen uptake and body weight is not constant. Kleiber's case for a linear relation between oxygen uptake and the [Formula: see text] power of body weight for homeotherms in general under normal environmental conditions is not impugned by the present findings. Under abnormal experimental conditions, particularly as regards environmental temperature, the use of the analysis of covariance is recommended to best allow for the effect of body weight on oxygen uptake.

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Validity and reproducibility of commercial cycling power meters in hot and cold environmental temperatures

Journal Of Science & Cycling ◽

10.28985/jsc.v8i1.504 ◽

2019 ◽

Vol 8 (1) ◽

pp. 32-39

Author(s):

Robert Shute ◽

Roksana Zak ◽

Dustin Slivka

Keyword(s):

Power Output ◽

Room Temperature ◽

Environmental Temperature ◽

Validity And Reliability ◽

Improve Performance ◽

Training Tool ◽

Power Meter ◽

Temperature Environment ◽

Different Temperatures ◽

Environmental Temperatures

Power meters are a training tool used to help cyclists improve performance by objectively monitoring intensity. Some power meters are well established and validated, whereas others are relatively new. Most power meters have been tested for validity and reliability in laboratory and field settings of similar conditions; however, the reproducibility of these power meters across different temperatures has not been established. To examine the potential differences of the CompuTrainer, PowerTap, Stages, and Vector power meters in hot and cold compared to a room temperature environment. Recreationally trained male (n=7) and female (n=3) participants each completed three incremental cycling trials in hot (33°C), cold (7°C), or room temperature (RT, 20°C) conditions. The power meters were placed on a standard road bicycle and power output was logged and recorded. The CompuTrainer was higher in the room temperature trial compared to the cold and the hot, but not between the hot and cold trial. The PowerTap was not different in RT and cold, but was lower in hot compared to RT and compared to cold. The Stages was not different between RT and cold, but was lower in the hot compared to RT and compared to cold. The Vector was not different between RT and cold but was lower in the hot compared to RT and compared to cold. These data indicate that environmental temperature may affect the reproducibility of power meters. It is important to recognize the potential differences between temperatures when choosing a power meter.

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Dealing with hot rocky environments: Critical thermal maxima and locomotor performance in Leptodactylus lithonaetes (Anura: Leptodactylidae)

Herpetological Journal ◽

10.33256/hj29.3.155161 ◽

2019 ◽

pp. 155-161 ◽

Cited By ~ 1

Author(s):

Ivan Beltran

Keyword(s):

Environmental Temperature ◽

Extreme Temperature ◽

Effect Of Temperature ◽

Maximum Speed ◽

Locomotor Performance ◽

Extreme Temperatures ◽

Physiological Limits ◽

Fitness Consequences ◽

Thermal Maximum ◽

Environmental Temperatures

Environmental temperature has fitness consequences on ectotherm development, ecology and behaviour. Amphibians are especially vulnerable because thermoregulation often trades with appropriate water balance. Although substantial research has evaluated the effect of temperature in amphibian locomotion and physiological limits, there is little information about amphibians living under extreme temperature conditions. Leptodactylus lithonaetes is a frog allegedly specialised to forage and breed on dark granitic outcrops and associated puddles, which reach environmental temperatures well above 40 ˚C. Adults can select thermally favourable microhabitats during the day while tadpoles are constrained to rock puddles and associated temperature fluctuations; we thus established microhabitat temperatures and tested whether the critical thermal maximum (CTmax) of L. lithonaetes is higher in tadpoles compared to adults. In addition, we evaluated the effect of water temperature on locomotor performance of tadpoles. Contrary to our expectations, puddle temperatures were comparable and even lower than those temperatures measured in the microhabitats used by adults in the daytime. Nonetheless, the CTmax was 42.3 ˚C for tadpoles and 39.7 ˚C for adults. Regarding locomotor performance, maximum speed and maximum distance travelled by tadpoles peaked around 34 ˚C, approximately 1 ˚C below the maximum puddle temperatures registered in the puddles. In conclusion, L. lithonaetes tadpoles have a higher CTmax compared to adults, suggesting a longer exposure to extreme temperatures that lead to maintain their physiological performance at high temperatures. We suggest that these conditions are adaptations to face the strong selection forces driven by this granitic habitat.

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Survival of mouse blastocysts after low-temperature preservation under high pressure

Acta Veterinaria Hungarica ◽

10.1556/avet.52.2004.4.10 ◽

2004 ◽

Vol 52 (4) ◽

pp. 479-487 ◽

Cited By ~ 7

Author(s):

Cs. Pribenszky ◽

M. Molnár ◽

S. Cseh ◽

L. Solti

Keyword(s):

Phase Transition ◽

Hydrostatic Pressure ◽

Low Temperature ◽

High Hydrostatic Pressure ◽

Room Temperature ◽

Freezing Point ◽

Significant Loss ◽

Embryo Cryopreservation ◽

Subzero Temperatures ◽

Survival Capacity

Cryoinjuries are almost inevitable during the freezing of embryos. The present study examines the possibility of using high hydrostatic pressure to reduce substantially the freezing point of the embryo-holding solution, in order to preserve embryos at subzero temperatures, thus avoiding all the disadvantages of freezing. The pressure of 210 MPa lowers the phase transition temperature of water to -21°C. According to the results of this study, embryos can survive in high hydrostatic pressure environment at room temperature; the time embryos spend under pressure without significant loss in their survival could be lengthened by gradual decompression. Pressurisation at 0°C significantly reduced the survival capacity of the embryos; gradual decompression had no beneficial effect on survival at that stage. Based on the findings, the use of the phenomena is not applicable in this form, since pressure and low temperature together proved to be lethal to the embryos in these experiments. The application of hydrostatic pressure in embryo cryopreservation requires more detailed research, although the experience gained in this study can be applied usefully in different circumstances.

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