scholarly journals FUNCTIONAL GENOMICS OF ADAPTATION TO HYPOXIC COLD-STRESS IN HIGH-ALTITUDE DEER MICE: TRANSCRIPTOMIC PLASTICITY AND THERMOGENIC PERFORMANCE

Evolution ◽  
2013 ◽  
Vol 68 (1) ◽  
pp. 48-62 ◽  
Author(s):  
Zachary A. Cheviron ◽  
Alex D. Connaty ◽  
Grant B. McClelland ◽  
Jay F. Storz
Keyword(s):  
Cold Stress ◽  
Functional Genomics ◽  
High Altitude ◽  
Deer Mice

scholarly journals Cold stress in the harvest period: effects on tobacco leaf quality and curing characteristics

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yan Li ◽  
Ke Ren ◽  
Mengyang Hu ◽  
Xian He ◽  
Kaiyuan Gu ◽  
...  
Keyword(s):  
Cold Stress ◽  
High Altitude ◽  
Weather Forecast ◽  
Production Quality ◽  
Chemical Components ◽  
Leaf Quality ◽  
Tobacco Leaves ◽  
Tobacco Leaf ◽  
Antioxidant Enzyme System

Abstract Background Weather change in high-altitude areas subjects mature tobacco (Nicotiana tabacum L.) to cold stress, which damages tobacco leaf yield and quality. A brupt diurnal temperature differences (the daily temperature dropping more than 20 °C) along with rainfall in tobacco-growing areas at an altitude above 2450 m, caused cold stress to field-grown tobacco. Results After the flue-cured tobacco suffered cold stress in the field, the surface color of tobacco leaves changed and obvious large browning areas were appeared, and the curing availability was extremely poor. Further research found the quality of fresh tobacco leaves, the content of key chemical components, and the production quality were greatly reduced by cold stress. We hypothesize that cold stress in high altitude environments destroyed the antioxidant enzyme system of mature flue-cured tobacco. Therefore, the quality of fresh tobacco leaves, the content of key chemical components, and the production quality were greatly reduced by cold stress. Conclusion This study confirmed that cold stress in high-altitude tobacco areas was the main reason for the browning of tobacco leaves during the tobacco curing process. This adverse environment seriously damaged the quality of tobacco leaves, but can be mitigated by pay attention to the weather forecast and pick tobacco leaves in advance.

Population variation in the metabolic response of deer mice to infection with Capillaria hepatica (Nematoda)

2001 ◽  
Vol 79 (4) ◽  
pp. 554-561 ◽  
Author(s):  
Shawn Meagher ◽  
Timothy P O'Connor
Keyword(s):  
Cold Stress ◽  
Metabolic Response ◽  
Host Population ◽  
Population Variation ◽  
Deer Mice ◽  
Negative Consequences ◽  
Capillaria Hepatica ◽  
Generation Times ◽  
Stress Maximum ◽  
Host Parasite

The effects of parasites on their hosts can vary among host populations, but few studies have examined geographic variation in host-parasite interactions. We examined the effects of Capillaria hepatica (Nematoda) infection on deer mice (Peromyscus maniculatus gracilis) from two different populations. Specifically, we measured the basal metabolic rate (BMR), cold-stress maximum oxygen consumption (MRpeak), metabolic scope (MRpeak/BMR), and thermogenic endurance of infected and uninfected mice from one population with, and a second population without, a history with C. hepatica. Infection had no effect on BMR, but did have effects on cold-stress measures. A previous study documented a significant relationship between survival and MRpeak in wild deer mice; hence, the effects of infection on the parameters that we measured could influence fitness. Only mice that had no historical association with C. hepatica displayed negative consequences of infection, which suggests that the historical host population has evolved mechanisms to cope with infection. Models of the evolution of virulence should include evolutionary responses of both hosts and parasites, particularly when systems involve macroparasites that have long generation times.

Low P50 in deer mice native to high altitude

1985 ◽  
Vol 58 (1) ◽  
pp. 193-199 ◽  
Author(s):  
L. R. Snyder
Keyword(s):  
High Altitude ◽  
Significant Negative Correlation ◽  
Deer Mice ◽  
Hypoxic Stress ◽  
Hemoglobin Saturation ◽  
Partial Pressures ◽  
Theoretical Predictions ◽  
Low Altitude ◽  
The Difference

Whereas it is widely believed that animals native to high altitude show lower O2 partial pressures at 50% hemoglobin saturation (P50) than do related animals native to low altitude, that “fact” has not been well documented. Consequently, P50 at pH 7.4, PCO2(7.4), the CO2 Bohr effect, and the buffer slope (delta log PCO2/delta pH) were determined via the mixing technique in Peromyscus maniculatus native to a range of altitudes but acclimated to 340 or 3,800 m. PCO2(7.4) and buffer slope were substantially lower at high altitude. The change in P50(7.4) between acclimation altitudes was minimal (0.8% increase at 3,800 m), because of counterbalancing changes in PCO2, 2,3-diphospho-D-glycerate concentration, and perhaps other factors. At both acclimation altitudes there was a highly significant negative correlation between P50(7.4) and native altitude. Since pH in vivo probably increases slightly at high altitude, the data on P50 corrected to pH 7.4 are probably underestimates of the difference in in vivo P50 at low vs. high altitude. Hence these results corroborate theoretical predictions that low P50 is advantageous under severe hypoxic stress.

scholarly journals Plasticity of non-shivering thermogenesis and brown adipose tissue in high-altitude deer mice

2021 ◽  
Author(s):  
Soren Z. Coulson ◽  
Cayleih E. Robertson ◽  
Sajeni Mahalingam ◽  
Grant B. McClelland
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
High Altitude ◽  
Heat Production ◽  
Mitochondrial Function ◽  
Mitochondrial Respiration ◽  
Deer Mice ◽  
Brown Adipose ◽  
Hypoxia Acclimation ◽  
Shivering Thermogenesis

High altitude environments challenge small mammals with persistent low ambient temperatures that require high rates of aerobic heat production in face of low O2 availability. An important component of thermogenic capacity in rodents is non-shivering thermogenesis (NST) mediated by uncoupled mitochondrial respiration in brown adipose tissue (BAT). NST is plastic, and capacity for heat production increases with cold acclimation. However, in lowland native rodents, hypoxia inhibits NST in BAT. We hypothesize that highland deer mice (Peromyscus maniculatus) overcome the hypoxic inhibition of NST through changes in BAT mitochondrial function. We tested this hypothesis using lab born and raised highland and lowland deer mice, and a lowland congeneric (P. leucopus), acclimated to either warm normoxia (25°C, 760 mmHg) or cold hypoxia (5°C, 430 mmHg). We determined the effects of acclimation and ancestry on whole-animal rates of NST, the mass of interscapular BAT (iBAT), and uncoupling protein (UCP)-1 protein expression. To identify changes in mitochondrial function, we conducted high-resolution respirometry on isolated iBAT mitochondria using substrates and inhibitors targeted to UCP-1. We found that rates of NST increased with cold hypoxia acclimation but only in highland deer mice. There was no effect of cold hypoxia acclimation on iBAT mass in any group, but highland deer mice showed increases in UCP-1 expression and UCP-1 stimulated mitochondrial respiration in response to these stressors. Our results suggest that highland deer mice have evolved to increase the capacity for NST in response to chronic cold hypoxia, driven in part by changes in iBAT mitochondrial function.

scholarly journals Genetic variation in haemoglobin alters breathing in high-altitude deer mice

2021 ◽  
Author(s):  
Catherine M. Ivy ◽  
Oliver H. Wearing ◽  
Chandrasekhar Natarajan ◽  
Rena M. Schweizer ◽  
Natalia Gutiérrez-Pinto ◽  
...  
Keyword(s):  
Genetic Variation ◽  
High Altitude ◽  
Globin Gene ◽  
Respiratory Physiology ◽  
Deer Mice ◽  
Emergent Properties ◽  
Mixed Genetic Background ◽  
Hypoxia Adaptation ◽  
Globin Gene Expression

ABSTRACTPhysiological systems often have emergent properties but the effects of genetic variation on physiology are often unknown, which presents a major challenge to understanding the mechanisms of phenotypic evolution. We investigated the in vivo effects on respiratory physiology of genetic variants in haemoglobin (Hb) that contribute to hypoxia adaptation in high-altitude deer mice (Peromyscus maniculatus). We created F2 inter-population hybrids of highland and lowland deer mice to test the phenotypic effects of α- and β-globin variants on a mixed genetic background. High-altitude genotypes were associated with breathing phenotypes that enhance O2 uptake in hypoxia, including a deeper more effective breathing pattern and an augmented hypoxic ventilatory response. These effects could not be explained by erythrocyte Hb-O2 affinity or globin gene expression in the brainstem. Therefore, adaptive variation in haemoglobin can have unexpected effects on physiology that are distinct from the canonical function of this protein in circulatory O2 transport.

Lipid Oxidation during Thermogenesis in High-Altitude Deer Mice (Peromyscus maniculatus)

2021 ◽  
Author(s):  
Sulayman Aslan Lyons ◽  
Kevin B Tate ◽  
Kenneth Collins Welch ◽  
Grant B. McClelland
Keyword(s):  
Lipid Oxidation ◽  
Palmitic Acid ◽  
High Altitude ◽  
Deer Mice ◽  
Acid Oxidation ◽  
Cold Environments ◽  
Oxidation Rates ◽  
Low Altitude ◽  
Land Mammal ◽  
Specific Lipid

When at their maximum thermogenic capacity (cold-induced V̇O2max), small endotherms reach levels of aerobic metabolism as high, or even higher, than running V̇O2max. How these high rates of thermogenesis are supported by substrate oxidation is currently unclear. The appropriate utilization of metabolic fuels that could sustain thermogenesis over extended periods may be important for survival in cold environments, like high altitude. Previous studies show that high capacities for lipid use in high-altitude deer mice may have evolved in concert with greater thermogenic capacities. The purpose of this study was to determine how lipid utilization at both moderate and maximal thermogenic intensities may differ in high- and low- altitude deer mice, and strictly low-altitude white-footed mice. We also examined the phenotypic plasticity of lipid use after acclimation to cold hypoxia (CH), conditions simulating high altitude. We found that lipids were the primary fuel supporting both moderate and maximal rates of thermogenesis in both species of mice. Lipid oxidation increased 3-fold in mice from 30oC to 0oC, consistent with increases in oxidation of [13C]-palmitic acid. CH acclimation led to an increase in [13C]-palmitic acid oxidation at 30oC but did not affect total lipid oxidation. Lipid oxidation rates at cold-induced V̇O2max were two- to four-fold those at 0oC and increased further after CH acclimation, especially in high-altitude deer mice. These are the highest mass-specific lipid oxidation rates observed in any land mammal. Uncovering the mechanisms that allow for these high rates of oxidation will aid our understanding of the regulation of lipid metabolism.

scholarly journals High-altitude rodents have abundant collaterals that protect against tissue injury after cerebral, coronary and peripheral artery occlusion

2020 ◽  
pp. 0271678X2094260
Author(s):  
James E Faber ◽  
Jay F Storz ◽  
Zachary A Cheviron ◽  
Hua Zhang
Keyword(s):  
High Altitude ◽  
Guinea Pigs ◽  
Prolonged Exposure ◽  
Tissue Injury ◽  
Atmospheric Oxygen ◽  
Arterial Occlusion ◽  
Oxygen Demand ◽  
Artery Occlusion ◽  
Deer Mice ◽  
Collateral Arteries

Collateral number/density varies widely in brain and other tissues among strains of Mus musculus mice due to differences in genetic background. Recent studies have shown that prolonged exposure to reduced atmospheric oxygen induces additional collaterals to form, suggesting that natural selection may favor increased collaterals in populations native to high-altitude. High-altitude guinea pigs ( Cavia) and deer mice ( Peromyscus) were compared with lowland species of Peromyscus, Mus and Rattus (9 species/strains examined). Collateral density, diameter and other morphometrics were measured in brain where, importantly, collateral abundance reflects that in other tissues of the same individual. Guinea pigs and high-altitude deer mice had a greater density of pial collaterals than lowlanders. Consistent with this, guinea pigs and highlander mice evidenced complete and 80% protection against stroke, respectively. They also sustained significantly less ischemia in heart and lower extremities after arterial occlusion. Vessels of the circle of Willis, including the communicating collateral arteries, also exhibited unique features in the highland species. Our findings support the hypothesis that species native to high-altitude have undergone genetic selection for abundant collaterals, suggesting that besides providing protection in obstructive disease, collaterals serve a physiological function to optimize oxygen delivery to meet oxygen demand when oxygen is limiting.

Sign in / Sign up

Export Citation Format

Share Document