Ice Slurry Ingestion and Physiological Strain During Exercise in Non-Compensable Heat Stress.

PubMed

Ng, Jason; Wingo, Jonathan E; Bishop, Phillip A; Casey, Jason C; Aldrich, Elizabeth K

2018-05-01

Precooling with ice slurry ingestion attenuates the increase in rectal temperature (Tre) during subsequent running and cycling. It remains unclear how this cooling method affects physiological strain during work while wearing protective garments. This study investigated the effect of ice slurry ingestion on physiological strain during work in hot conditions while wearing firefighter protective clothing. In three counterbalanced trials, eight men (mean ± SD; age = 21 ± 2 yr, height = 179.5 ± 3.5 cm, mass = 79.1 ± 4.1 kg, body fat = 11.4 ± 3.7%) wore firefighter protective clothing and walked (4 km · h-1, 12% incline, ∼7 METs) for 30 min in hot conditions (35°C, 40% RH). Every 2.5 min, subjects ingested 1.25 g · kg-1 (relative total: 15 g · kg-1, absolute total: 1186.7 ± 61.3 g) of a tepid (22.4 ± 1.7°C), cold (7.1 ± 1.5°C), or ice slurry (-1.3 ± 0.2°C) beverage. Heart rates (HR) were lower with ice slurry ingestion compared to both fluid trials starting 5 min into exercise (tepid = 158 ± 14, cold = 157 ± 11, ice slurry = 146 ± 13 bpm) and persisting for the remainder of the bout (min 30: tepid = 196 ± 10, cold = 192 ± 10, ice slurry = 181 ± 13 bpm). Tre was lower with ice slurry ingestion compared to cold and tepid trials (min 5: tepid = 37.17 ± 0.38, cold = 37.17 ± 0.39, ice slurry = 37.05 ± 0.43°C; min 30: tepid = 38.15 ± 0.29, cold = 38.31 ± 0.36, ice slurry = 37.95 ± 0.32°C). The physiological strain index (PSI) was lower with ice slurry ingestion compared to fluid trials starting at min 5 (tepid = 3.8 ± 0.7, cold = 3.8 ± 0.6, ice slurry = 3.0 ± 0.5) and remained lower throughout exercise (min 30: tepid = 8.2 ± 0.6, cold = 8.3 ± 0.9, ice slurry = 6.9 ± 1.2). A large quantity of ice slurry ingested under non-compensable heat stress conditions mitigated physiological strain during exercise by blunting the rise in heart rate and rectal temperature.Ng J, Wingo JE, Bishop PA, Casey JC, Aldrich EK. Ice slurry ingestion and physiological strain during exercise in non-compensable heat stress. Aerosp Med Hum Perform. 2018; 89(5):434-441.

In Vivo Assessment of Cold Tolerance through Chlorophyll-a Fluorescence in Transgenic Zoysiagrass Expressing Mutant Phytochrome A

PubMed Central

Gururani, Mayank Anand; Venkatesh, Jelli; Ganesan, Markkandan; Strasser, Reto Jörg; Han, Yunjeong; Kim, Jeong-Il; Lee, Hyo-Yeon; Song, Pill-Soon

2015-01-01

Chlorophyll-a fluorescence analysis provides relevant information about the physiology of plants growing under abiotic stress. In this study, we evaluated the influence of cold stress on the photosynthetic machinery of transgenic turfgrass, Zoysia japonica, expressing oat phytochrome A (PhyA) or a hyperactive mutant phytochrome A (S599A) with post-translational phosphorylation blocked. Biochemical analysis of zoysiagrass subjected to cold stress revealed reduced levels of hydrogen peroxide, increased proline accumulation, and enhanced specific activities of antioxidant enzymes compared to those of control plants. Detailed analyses of the chlorophyll-a fluorescence data through the so-called OJIP test exhibited a marked difference in the physiological status among transgenic and control plants. Overall, these findings suggest an enhanced level of cold tolerance in S599A zoysiagrass cultivars as reflected in the biochemical and physiological analyses. Further, we propose that chlorophyll-a fluorescence analysis using OJIP test is an efficient tool in determining the physiological status of plants under cold stress conditions. PMID:26010864

Physiological response to low temperature in the freshwater apple snail, Pomacea canaliculata (Gastropoda: Ampullariidae).

PubMed

Matsukura, Keiichiro; Tsumuki, Hisaaki; Izumi, Yohei; Wada, Takashi

2009-08-01

Cold hardiness of the freshwater apple snail, Pomacea canaliculata, varies seasonally. We investigated lethal factors and physiological changes arising from exposure of P. canaliculata to low temperatures. Snails did not survive freezing. The supercooling point of cold-acclimated (cold tolerant) snails (-6.6+/-0.8 degrees C) did not differ significantly from that of non-acclimated ones (-7.1+/-1.5 degrees C) under laboratory conditions. Furthermore, snails died even under more moderately low temperatures approaching 0 degrees C. These results indicate that indirect chilling injury is a factor in the death of P. canaliculata at low temperatures. Regardless of whether the snails were acclimated to low temperatures, all of the dead, and even some of the snails still alive at 0 degrees C, had injured mantles, indicating that the mantle may be the organ most susceptible to the effects of low temperatures. The concentration of glucose in the posterior chamber of the kidney and concentration of glycerol in the digestive gland were significantly higher in cold-acclimated snails than in non-acclimated ones, suggesting carbohydrate metabolic pathways are altered in snails during cold acclimation.

Intermittent whole-body cold immersion induces similar thermal stress but different motor and cognitive responses between males and females.

PubMed

Solianik, Rima; Skurvydas, Albertas; Mickevičienė, Dalia; Brazaitis, Marius

2014-10-01

The main aim of this study was to compare the thermal responses and the responses of cognitive and motor functions to intermittent cold stress between males and females. The intermittent cold stress continued until rectal temperature (TRE) reached 35.5°C or for a maximum of 170 min. Thermal response and motor and cognitive performance were monitored. During intermittent cold stress, body temperature variables decreased in all subjects (P < 0.001) and did not differ between sexes. The presence of fast and slow cooling types for participants with similar effect on physiological variables were observed; thus the different rate coolers were grouped together and were attributed only sex specific responses. Overall, TRE cooling rate and cold strain index did not differ between sexes. Maximal voluntary contraction (MVC) decreased after intermittent cold exposure only in males (P < 0.001), whereas changes in muscle electromyography (EMG) activity did not differ between sexes. The effects of intermittent cold stress on electrically evoked muscle properties, spinal (H-reflex), and supraspinal (V-waves) reflexes did not differ between sexes. Intermittent cold-induced cognitive perturbation of attention and memory task performance was greater in males (P < 0.05). Contrary to our expectations, the results of the present study indicated that males and females experience similar thermal stress induced by intermittent whole-body cold immersion. Although no sex-specific differences were observed in muscle EMG activity, involuntary muscle properties, spinal and supraspinal reflexes, some of the sex differences observed (e.g., lower isometric MVC and greater cognitive perturbation in males) support the view of sex-specific physiological responses to core temperature decrease. Copyright © 2014 Elsevier Inc. All rights reserved.

Physiological Evaluation of A1 (Extreme-Cold-Weather) and A2 (Buoyant, Intermediate-Cold-Weather) Jackets.

DTIC Science & Technology

1983-08-01

the resting metabolic heat will be dissipated through the clothing with the remaining 25% lost through the respiratory tract and insensible sweating...AD-A258 410 PHYSIOLOGICAL EVALUATION OF Al (EXTREME-COLD-WEATHER) AND A2 (BUOYANT, INTERMEDIATE-COLD-WEATHER) JACKETS NAVY CLOTHING AND TEXTILE...Navy Clothing and Textile Research Facility 523-003-30-06 21 Strathmore Road 523-003-30-08 Natick, MA 01760 11. CONTROLLING OFFICE NAME AND ADDRESS

Plasticity and local adaptation explain lizard cold tolerance.

PubMed

Card, Daren C; Schield, Drew R; Castoe, Todd A

2018-05-01

How does climate variation limit the range of species and what does it take for species to colonize new regions? In this issue of Molecular Ecology, Campbell-Staton et al. () address these broad questions by investigating cold tolerance adaptation in the green anole lizard (Anolis carolinensis) across a latitudinal transect. By integrating physiological data, gene expression data and acclimation experiments, the authors disentangle the mechanisms underlying cold adaptation. They first establish that cold tolerance adaptation in Anolis lizards follows the predictions of the oxygen- and capacity-limited thermal tolerance hypothesis, which states that organisms are limited by temperature thresholds at which oxygen supply cannot meet demand. They then explore the drivers of cold tolerance at a finer scale, finding evidence that northern populations are adapted to cooler thermal regimes and that both phenotypic plasticity and heritable genetic variation contribute to cold tolerance. The integration of physiological and gene expression data further highlights the varied mechanisms that drive cold tolerance adaptation in Anolis lizards, including both supply-side and demand-side adaptations that improve oxygen economy. Altogether, their work provides new insight into the physiological and genetic mechanisms underlying adaptation to new climatic niches and demonstrates that cold tolerance in northern lizard populations is achieved through the synergy of physiological plasticity and local genetic adaptation for thermal performance. © 2018 John Wiley & Sons Ltd.

Physiological reaction to work in cold microclimate.

PubMed

Bortkiewicz, Alicja; Gadzicka, Elzbieta; Szymczak, Wiesław; Szyjkowska, Agata; Koszada-Włodarczyk, Wiesława; Makowiec-Dabrowska, Teresa

2006-01-01

In Poland, occupational exposure to cold microclimate is quite common (5.1 workers/1000 occupationally active people). Reports on health effects of this exposure are rather scarce. The aim of the study was to evaluate the physiological reaction in workers occupationally exposed to cold microclimate. Examinations were performed in a group of 102 workers (41 women and 61 men) employed at cold storage units. The mean age in the group was 39.1 +/- 9.9 years and the duration of employment under conditions of cold environment was over 12 years. The study population was divided into four groups, according to microclimate conditions (group I, ambient temperature -26 degrees C; group II, 10-14 degrees C; group III, 18-20 degrees C, control group; and group IV, 0-10 degress C). The workers underwent the following procedures: general medical examinations, cold pressor test, ambulatory blood pressure monitoring, and heart rate variability (HRV) analysis (time- and frequency-domain parameters). The results were adjusted for confounding factors (age, smoking and drinking habits). The analysis of HRV parameters did not reveal any significant differences between the study groups. However, systolic and diastolic blood pressure (BP) in the daytime and at night was significantly higher in group IV compared to group II. Mean heart rate (HR) in the daytime and at night and the BP and HR day/night ratio did not differ between the groups. The analysis of BP by gender revealed that in women, systolic BP during the day and at night was significantly higher in group IV than in group II. In the group of workers with hypertension (18 men and 5 women), men reacted to the cold pressor test either by increased or decreased BP while all the women reacted by the increased BP. Our findings indicated that in workers exposed to cold microclimate, the physiological reaction was dependent on gender and ambient temperature. Women seemed to be more sensitive to cold stress than men. However, this finding must be further investigated.

Plasticity and stress tolerance override local adaptation in the responses of Mediterranean holm oak seedlings to drought and cold.

PubMed

Gimeno, Teresa E; Pías, Beatriz; Lemos-Filho, José P; Valladares, Fernando

2009-01-01

Plant populations of widely distributed species experience a broad range of environmental conditions that can be faced by phenotypic plasticity or ecotypic differentiation and local adaptation. The strategy chosen will determine a population's ability to respond to climate change. To explore this, we grew Quercus ilex (L.) seedlings from acorns collected at six selected populations from climatically contrasting localities and evaluated their response to drought and late season cold events. Maximum photosynthetic rate (A(max)), instantaneous water use efficiency (iWUE), and thermal tolerance to freeze and heat (estimated from chlorophyll fluorescence versus temperature curves) were measured in 5-month-old seedlings in control (no stress), drought (water-stressed), and cold (low suboptimal temperature) conditions. The observed responses were similar for the six populations: drought decreased A(max) and increased iWUE, and cold reduced A(max) and iWUE. All the seedlings maintained photosynthetic activity under adverse conditions (drought and cold), and rapidly increased their iWUE by closing stomata when exposed to drought. Heat and freeze tolerances were similarly high for seedlings from all the populations, and they were significantly increased by drought and cold, respectively; and were positively related to each other. Differences in seedling performance across populations were primarily induced by maternal effects mediated by seed size and to a lesser extent by idiosyncratic physiologic responses to drought and low temperatures. Tolerance to multiple stresses together with the capacity to physiologically acclimate to heat waves and cold snaps may allow Q. ilex to cope with the increasingly stressful conditions imposed by climate change. Lack of evidence of physiologic seedling adaptation to local climate may reflect opposing selection pressures to complex, multidimensional environmental conditions operating within the distribution range of this species.

Thermal and metabolic responses of military divers during a 6-hour static dive in cold water.

PubMed

Riera, Florence; Horr, Reed; Xu, Xiaojiang; Melin, Bruno; Regnard, Jacques; Bourdon, Lionel

2014-05-01

Human thermal responses during prolonged whole-body immersion in cold water are of interest for the military, especially French SEALS. This study aims at describing the thermo-physiological responses. There were 10 male military divers who were randomly assigned to a full immersion in neutral (34 degrees C), moderately cold (18 degrees C), and cold (10 degrees C) water wearing their operational protective devices (5.5 mm wetsuit with 3.0 mm thick underwear) for 6 h in a static position. Rectal temperature (T(re)) and 14 skin temperatures (T(sk)), blood analysis (stress biomarkers, metabolic substrates), and oxygen consumption (Vo2) were collected. At 34 degrees C, there were no significant modifications of the thermo-physiological responses over time. The most interesting result was that rates of rectal temperature decrease (0.15 +/- 0.02 degrees C x min(-1)) were the same between the two cold stress experimental conditions (at 18 degrees C and 10 degrees C). At the final experiment, rectal temperature was not significantly different between the two cold stress experimental conditions. Mean T(sk) decreased significantly during the first 3 h of immersion and then stabilized at a lower level at 10 degrees C (25.6 +/- 0.8 degrees C) than at 18 degrees C (29.3 +/- 0.9 degrees C). Other results demonstrate that the well-trained subjects developed effective physiological reactions. However, these reactions are consistently too low to counterbalance the heat losses induced by cold temperature conditions and long-duration immersion. This study shows that providing divers with thermal protection is efficient for a long-duration immersion from a medical point of view, but not from an operational one when skin extremities were taken into account.

Methyl parathion and fenvalerate toxicity in American kestrels: Acute physiological responses and effects of cold

USGS Publications Warehouse

Rattner, B.A.; Franson, J.C.

1984-01-01

Physiological and toxicological effects of p.o. methyl parathion (0.375-3.0 mg/kg) or fenvalerate (1000-4000 mg/kg) were examined over a 10-h period in American kestrels (Falco sparverius) maintained in thermoneutral (22?C) and cold (-5?C) environments. Methyl parathion was highly toxic (estimated median lethal dose of 3.08 mg/kg, 95% confidence limits of 2.29 -4.14 mg/kg), producing dose-dependent inhibition of brain and plasma cholinesterase activity, hyperglycemia, and elevated plasma corticosterone concentration. Brain and plasma cholinesterase inhibition in excess of 50% was associated with transient but pronounced hypothermia 2 h after intubation, although the magnitude of this response was yariable. Fenvalerate, at doses far exceeding those encountered in the environment, caused mild intoxication and elevated plasma alanine aminotransferase activity. Cold intensified methyl parathion toxicity, but did not affect that of fenvalerate. Thus, it would appear that organophosphorus insecticides pose far greater hazard than pyrethroids to raptorial birds.

Teaching in a Cold Environment.

ERIC Educational Resources Information Center

Ewert, Alan

1979-01-01

Designed to help teachers deal with students in a cold environment, this article explains cold physiology and fundamental laws of heat; describes 14 common cold injuries and their current treatment; and lists a number of useful teaching techniques for cold environments. (SB)

Human cold stress of strong local-wind "Hijikawa-arashi" in Japan, based on the UTCI index and thermo-physiological responses

NASA Astrophysics Data System (ADS)

Ohashi, Yukitaka; Katsuta, Takumi; Tani, Haruka; Okabayashi, Taiki; Miyahara, Satoshi; Miyashita, Ryoji

2018-03-01

We investigated the cold stress caused by a strong local wind called "Hijikawa-arashi," through in situ vital measurements and the Universal Thermal Climate Index (UTCI). This wind is a very interesting winter phenomenon, localized in an area within 1 km of the seashore in Ozu City, Ehime Prefecture in Japan. When a strong Hijikawa-arashi (HA) occurred at 14-15 m s-1, the UTCI decreased to - 30 °C along the bridge where commuting residents are the most exposed to strong and cold winds. On the bridge, most participants in our experiment felt "very cold" or "extremely cold." The UTCI of HA can be predicted from a multiple regression equation using wind speed and air temperature. The cold HA wind is also harmful to human thermo-physiological responses. It leads to higher blood pressure and increased heart rate, both of which act as cardiovascular stress triggers. Increases of 6-10 mmHg and 3-6 bpm for every 10 °C reduction in UTCI were seen on all observational days, including HA and non-HA days. In fact, the participants' body skin temperatures decreased by approximately 1.2 to 1.7 °C for every 10 °C reduction in UTCI. Thus, the UTCI variation due to the HA outbreak corresponded well with the cold sensation and thermo-physiological responses in humans. This result suggests that daily UTCI monitoring enables the prediction of thermo-physiological responses to the HA cold stress.

What is the biochemical and physiological rationale for using cold-water immersion in sports recovery? A systematic review.

PubMed

Bleakley, Chris M; Davison, Gareth W

2010-02-01

Cold-water immersion (CWI) is a popular recovery intervention after exercise. The scientific rationale is not clear, and there are no clear guidelines for its use. The aim of this review was to study the physiological and biochemical effect of short periods of CWI. A computer-based literature search, citation tracking and related articles searches were undertaken. Primary research studies using healthy human participants, immersed in cold water (<15 degrees C), for 5 min durations or less were included. Data were extracted on body temperature, cardiovascular, respiratory and biochemical response. 16 studies were included. Sample size was restricted, and there was a large degree of study heterogeneity. CWI was associated with an increase in heart rate, blood pressure, respiratory minute volume and metabolism. Decreases in end tidal carbon dioxide partial pressure and a decrease in cerebral blood flow were also reported. There was evidence of increases in peripheral catecholamine concentration, oxidative stress and a possible increase in free-radical-species formation. The magnitude of these responses may be attenuated with acclimatisation. CWI induces significant physiological and biochemical changes to the body. Much of this evidence is derived from full body immersions using resting healthy participants. The physiological and biochemical rationale for using short periods of CWI in sports recovery still remains unclear.

Radiative and Physiological Effects of Increased CO2. How does this interaction affect Climate in the Mediterranean Region?

NASA Technical Reports Server (NTRS)

Bounoua, Lahouari

2007-01-01

the radiative and physiological effects of doubled atmospheric carbon dioxide concentration (CO2) on climate are described using climate simulations. When CO2 was increased for vegetation only assuming no radiative effect, the response was a decrease in stomatal conductance followed by a temperature increase. This temperature increase was stronger when the vegetation physiological down-regulation was allowed in the model. The radiative forcing alone did not affect the global mean photosynthesis, however, some stimulation was observed in cold places. The interactions between the physiological and the radiative effects of doubled CO2 are not linearly additive and when acting together they tend to reduce the warming in the Mediterranean region.

Evolutionary stasis and lability in thermal physiology in a group of tropical lizards.

PubMed

Muñoz, Martha M; Stimola, Maureen A; Algar, Adam C; Conover, Asa; Rodriguez, Anthony J; Landestoy, Miguel A; Bakken, George S; Losos, Jonathan B

2014-03-07

Understanding how quickly physiological traits evolve is a topic of great interest, particularly in the context of how organisms can adapt in response to climate warming. Adjustment to novel thermal habitats may occur either through behavioural adjustments, physiological adaptation or both. Here, we test whether rates of evolution differ among physiological traits in the cybotoids, a clade of tropical Anolis lizards distributed in markedly different thermal environments on the Caribbean island of Hispaniola. We find that cold tolerance evolves considerably faster than heat tolerance, a difference that results because behavioural thermoregulation more effectively shields these organisms from selection on upper than lower temperature tolerances. Specifically, because lizards in very different environments behaviourally thermoregulate during the day to similar body temperatures, divergent selection on body temperature and heat tolerance is precluded, whereas night-time temperatures can only be partially buffered by behaviour, thereby exposing organisms to selection on cold tolerance. We discuss how exposure to selection on physiology influences divergence among tropical organisms and its implications for adaptive evolutionary response to climate warming.

Evolutionary stasis and lability in thermal physiology in a group of tropical lizards

PubMed Central

Muñoz, Martha M.; Stimola, Maureen A.; Algar, Adam C.; Conover, Asa; Rodriguez, Anthony J.; Landestoy, Miguel A.; Bakken, George S.; Losos, Jonathan B.

2014-01-01

Understanding how quickly physiological traits evolve is a topic of great interest, particularly in the context of how organisms can adapt in response to climate warming. Adjustment to novel thermal habitats may occur either through behavioural adjustments, physiological adaptation or both. Here, we test whether rates of evolution differ among physiological traits in the cybotoids, a clade of tropical Anolis lizards distributed in markedly different thermal environments on the Caribbean island of Hispaniola. We find that cold tolerance evolves considerably faster than heat tolerance, a difference that results because behavioural thermoregulation more effectively shields these organisms from selection on upper than lower temperature tolerances. Specifically, because lizards in very different environments behaviourally thermoregulate during the day to similar body temperatures, divergent selection on body temperature and heat tolerance is precluded, whereas night-time temperatures can only be partially buffered by behaviour, thereby exposing organisms to selection on cold tolerance. We discuss how exposure to selection on physiology influences divergence among tropical organisms and its implications for adaptive evolutionary response to climate warming. PMID:24430845

The effects of a hot drink on nasal airflow and symptoms of common cold and flu.

PubMed

Sanu, A; Eccles, R

2008-12-01

Hot drinks are a common treatment for common cold and flu but there are no studies reported in the scientific and clinical literature on this mode of treatment. This study investigated the effects of a hot fruit drink on objective and subjective measures of nasal airflow, and on subjective scores for common cold/flu symptoms in 30 subjects suffering from common cold/flu. The results demonstrate that the hot drink had no effect on objective measurement of nasal airflow but it did cause a significant improvement in subjective measures of nasal airflow. The hot drink provided immediate and sustained relief from symptoms of runny nose, cough, sneezing, sore throat, chilliness and tiredness, whereas the same drink at room temperature only provided relief from symptoms of runny nose, cough and sneezing. The effects of the drinks are discussed in terms of a placebo effect and physiological effects on salivation and airway secretions. In conclusion the results support the folklore that a hot tasty drink is a beneficial treatment for relief of most symptoms of common cold and flu.

Human whole body cold adaptation.

PubMed

Daanen, Hein A M; Van Marken Lichtenbelt, Wouter D

2016-01-01

Reviews on whole body human cold adaptation generally do not distinguish between population studies and dedicated acclimation studies, leading to confusing results. Population studies show that indigenous black Africans have reduced shivering thermogenesis in the cold and poor cold induced vasodilation in fingers and toes compared to Caucasians and Inuit. About 40,000 y after humans left Africa, natives in cold terrestrial areas seems to have developed not only behavioral adaptations, but also physiological adaptations to cold. Dedicated studies show that repeated whole body exposure of individual volunteers, mainly Caucasians, to severe cold results in reduced cold sensation but no major physiological changes. Repeated cold water immersion seems to slightly reduce metabolic heat production, while repeated exposure to milder cold conditions shows some increase in metabolic heat production, in particular non-shivering thermogenesis. In conclusion, human cold adaptation in the form of increased metabolism and insulation seems to have occurred during recent evolution in populations, but cannot be developed during a lifetime in cold conditions as encountered in temperate and arctic regions. Therefore, we mainly depend on our behavioral skills to live in and survive the cold.

Human whole body cold adaptation

PubMed Central

Daanen, Hein A.M.; Van Marken Lichtenbelt, Wouter D.

2016-01-01

ABSTRACT Reviews on whole body human cold adaptation generally do not distinguish between population studies and dedicated acclimation studies, leading to confusing results. Population studies show that indigenous black Africans have reduced shivering thermogenesis in the cold and poor cold induced vasodilation in fingers and toes compared to Caucasians and Inuit. About 40,000 y after humans left Africa, natives in cold terrestrial areas seems to have developed not only behavioral adaptations, but also physiological adaptations to cold. Dedicated studies show that repeated whole body exposure of individual volunteers, mainly Caucasians, to severe cold results in reduced cold sensation but no major physiological changes. Repeated cold water immersion seems to slightly reduce metabolic heat production, while repeated exposure to milder cold conditions shows some increase in metabolic heat production, in particular non-shivering thermogenesis. In conclusion, human cold adaptation in the form of increased metabolism and insulation seems to have occurred during recent evolution in populations, but cannot be developed during a lifetime in cold conditions as encountered in temperate and arctic regions. Therefore, we mainly depend on our behavioral skills to live in and survive the cold. PMID:27227100

Human cold stress of strong local-wind "Hijikawa-arashi" in Japan, based on the UTCI index and thermo-physiological responses.

PubMed

Ohashi, Yukitaka; Katsuta, Takumi; Tani, Haruka; Okabayashi, Taiki; Miyahara, Satoshi; Miyashita, Ryoji

2018-03-30

We investigated the cold stress caused by a strong local wind called "Hijikawa-arashi," through in situ vital measurements and the Universal Thermal Climate Index (UTCI). This wind is a very interesting winter phenomenon, localized in an area within 1 km of the seashore in Ozu City, Ehime Prefecture in Japan. When a strong Hijikawa-arashi (HA) occurred at 14-15 m s -1 , the UTCI decreased to - 30 °C along the bridge where commuting residents are the most exposed to strong and cold winds. On the bridge, most participants in our experiment felt "very cold" or "extremely cold." The UTCI of HA can be predicted from a multiple regression equation using wind speed and air temperature. The cold HA wind is also harmful to human thermo-physiological responses. It leads to higher blood pressure and increased heart rate, both of which act as cardiovascular stress triggers. Increases of 6-10 mmHg and 3-6 bpm for every 10 °C reduction in UTCI were seen on all observational days, including HA and non-HA days. In fact, the participants' body skin temperatures decreased by approximately 1.2 to 1.7 °C for every 10 °C reduction in UTCI. Thus, the UTCI variation due to the HA outbreak corresponded well with the cold sensation and thermo-physiological responses in humans. This result suggests that daily UTCI monitoring enables the prediction of thermo-physiological responses to the HA cold stress.

Brown adipose tissue (BAT) specific vaspin expression is increased after obesogenic diets and cold exposure and linked to acute changes in DNA-methylation.

PubMed

Weiner, Juliane; Rohde, Kerstin; Krause, Kerstin; Zieger, Konstanze; Klöting, Nora; Kralisch, Susan; Kovacs, Peter; Stumvoll, Michael; Blüher, Matthias; Böttcher, Yvonne; Heiker, John T

2017-06-01

Several studies have demonstrated anti-diabetic and anti-obesogenic properties of visceral adipose tissue-derived serine protease inhibitor (vaspin) and so evoked its potential use for treatment of obesity-related diseases. The aim of the study was to unravel physiological regulators of vaspin expression and secretion with a particular focus on its role in brown adipose tissue (BAT) biology. We analyzed the effects of obesogenic diets and cold exposure on vaspin expression in liver and white and brown adipose tissue (AT) and plasma levels. Vaspin expression was analyzed in isolated white and brown adipocytes during adipogenesis and in response to adrenergic stimuli. DNA-methylation within the vaspin promoter was analyzed to investigate acute epigenetic changes after cold-exposure in BAT. Our results demonstrate a strong induction of vaspin mRNA and protein expression specifically in BAT of both cold-exposed and high-fat (HF) or high-sugar (HS) fed mice. While obesogenic diets also upregulated hepatic vaspin mRNA levels, cold exposure tended to increase vaspin gene expression of inguinal white adipose tissue (iWAT) depots. Concomitantly, vaspin plasma levels were decreased upon obesogenic or thermogenic triggers. Vaspin expression was increased during adipogenesis but unaffected by sympathetic activation in brown adipocytes. Analysis of vaspin promoter methylation in AT revealed lowest methylation levels in BAT, which were acutely reduced after cold exposure. Our data demonstrate a novel BAT-specific regulation of vaspin gene expression upon physiological stimuli in vivo with acute epigenetic changes that may contribute to cold-induced expression in BAT. We conclude that these findings indicate functional relevance and potentially beneficial effects of vaspin in BAT function.

Mechanisms underpinning the beneficial effects of fluctuating thermal regimes in insect cold tolerance

USDA-ARS?s Scientific Manuscript database

Insects exposed to low temperature often have high mortality or exhibit sublethal effects. A growing number of recent studies have shown beneficial effects of exposing insects to recurrent brief warm pulses during low temperature stress (fluctuating thermal regimes, FTR). The physiological underpinn...

Physiological responses to cold (10° C) in men after six months' practice of yoga exercises

NASA Astrophysics Data System (ADS)

Selvamurthy, W.; Ray, U. S.; Hegde, K. S.; Sharma, R. P.

1988-09-01

A study was conducted on 30 healthy soldiers (age: 40 46 years) to assess the effect of selected yogic exercises (asanas) on some physiological responses to cold exposure. They were randomly divided into two groups of 15 each. One group performed regular physical exercises of physical training (PT), while the other group practised yogic exercises. At the end of 6 months of training, both the groups were exposed together to cold stress at 10°C for 2 h, and the following parameters were periodically monitored during cold exposure: heart rate ( fH), blood pressure ( BP), cardiac output(dot Q_c ), oral temperature (Tor), skin temperature ( T sk), respiratory rate ( fR), minute ventilation(dot V_E ), oxygen consumption(dot V_{O_2 } ), and shivering response by integrated electromyogram (EMG). There were progressive increases in BP, fR,dot V_E ,dot V_{O_2 } , anddot Q_c and decreases in fH, T or and T sk during cold exposure in both the groups. However, the decrease in T or and the increases indot V_{O_2 } anddot V_E were relatively lower ( P<0.01) in the yoga group as compared to the PT group. The shivering response appeared much earlier and was more intense in the PT group. These findings suggest that practice of yoga exercises may improve cold tolerance.

Body temperature and cold sensation during and following exercise under temperate room conditions in cold-sensitive young trained females.

PubMed

Fujii, Naoto; Aoki-Murakami, Erii; Tsuji, Bun; Kenny, Glen P; Nagashima, Kei; Kondo, Narihiko; Nishiyasu, Takeshi

2017-11-01

We evaluated cold sensation at rest and in response to exercise-induced changes in core and skin temperatures in cold-sensitive exercise trained females. Fifty-eight trained young females were screened by a questionnaire, selecting cold-sensitive (Cold-sensitive, n  = 7) and non-cold-sensitive (Control, n  = 7) individuals. Participants rested in a room at 29.5°C for ~100 min after which ambient temperature was reduced to 23.5°C where they remained resting for 60 min. Participants then performed 30-min of moderate intensity cycling (50% peak oxygen uptake) followed by a 60-min recovery. Core and mean skin temperatures and cold sensation over the whole-body and extremities (fingers and toes) were assessed throughout. Resting core temperature was lower in the Cold-sensitive relative to Control group (36.4 ± 0.3 vs. 36.7 ± 0.2°C). Core temperature increased to similar levels at end-exercise (~37.2°C) and gradually returned to near preexercise rest levels at the end of recovery (>36.6°C). Whole-body cold sensation was greater in the Cold-sensitive relative to Control group during resting at a room temperature of 23.5°C only without a difference in mean skin temperature between groups. In contrast, cold sensation of the extremities was greater in the Cold-sensitive group prior to, during and following exercise albeit this was not paralleled by differences in mean extremity skin temperature. We show that young trained females who are sensitive to cold exhibit augmented whole-body cold sensation during rest under temperate ambient conditions. However, this response is diminished during and following exercise. In contrast, cold sensation of extremities is augmented during resting that persists during and following exercise. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

A primer on clothing systems for cold-weather field work

USGS Publications Warehouse

Denner, Jon

1990-01-01

Conducting field work in cold weather is a demanding task. The most important safety consideration for field personnel is to maintain normal body temperature and avoid hypothermia.The human body adjusts to cold temperatures through different physiological processes. Heat production is enhanced by increases in the rates of basal metabolism, specific dynamic action, and physical exercise, and heat loss is reduced by vasoconstriction.Physiological adaptations alone are inadequate to stop rapid heat loss in cold temperatures. Additional insulation in the form of cold-weather clothing is necessary to retain heat.The most practical method of dressing for winter conditions is the layering system. Wearing multiple thin layers allows one to fine tune the insulation needed for different temperatures and activity levels.

Comparison of UTCI with Other Thermal Indices in the Assessment of Heat and Cold Effects on Cardiovascular Mortality in the Czech Republic

PubMed Central

Urban, Aleš; Kyselý, Jan

2014-01-01

We compare the recently developed Universal Thermal Climate Index (UTCI) with other thermal indices in analysing heat- and cold-related effects on cardiovascular (CVD) mortality in two different (urban and rural) regions in the Czech Republic during the 16-year period from 1994–2009. Excess mortality is represented by the number of deaths above expected daily values, the latter being adjusted for long-term changes, annual and weekly cycles, and epidemics of influenza/acute respiratory infections. Air temperature, UTCI, Apparent Temperature (AT) and Physiologically Equivalent Temperature (PET) are applied to identify days with heat and cold stress. We found similar heat effects on CVD mortality for air temperature and the examined thermal indices. Responses of CVD mortality to cold effects as characterised by different indices were much more varied. Particularly important is the finding that air temperature provides a weak cold effect in comparison with the thermal indices in both regions, so its application—still widespread in epidemiological studies—may underestimate the magnitude of cold-related mortality. These findings are important when possible climate change effects on heat- and cold-related mortality are estimated. AT and PET appear to be more universal predictors of heat- and cold- related mortality than UTCI when both urban and rural environments are of concern. UTCI tends to select windy rather than freezing days in winter, though these show little effect on mortality in the urban population. By contrast, significant cold-related mortality in the rural region if UTCI is used shows potential for UTCI to become a useful tool in cold exposure assessments. PMID:24413706

Hand immersion in cold water alleviating physiological strain and increasing tolerance to uncompensable heat stress.

PubMed

Khomenok, Gennadi A; Hadid, Amir; Preiss-Bloom, Orahn; Yanovich, Ran; Erlich, Tomer; Ron-Tal, Osnat; Peled, Amir; Epstein, Yoram; Moran, Daniel S

2008-09-01

The current study examines the use of hand immersion in cold water to alleviate physiological strain caused by exercising in a hot climate while wearing NBC protective garments. Seventeen heat acclimated subjects wearing a semi-permeable NBC protective garment and a light bulletproof vest were exposed to a 125 min exercise-heat stress (35 degrees C, 50% RH; 5 km/h, 5% incline). The heat stress exposure routine included 5 min rest in the chamber followed by two 50:10 min work-rest cycles. During the control trial (CO), there was no intervention, whilst in the intervention condition the subjects immersed their hands and forearms in a 10 degrees C water bath (HI). The results demonstrated that hand immersion in cold water significantly reduced physiological strain. In the CO exposure during the first and second resting periods, the average rectal temperature (T (re)) practically did not decrease. With hand immersion, the mean (SD) T (re) decreased by 0.45 (0.05 degrees C) and 0.48 degrees C (0.06 degrees C) during the first and second rest periods respectively (P < 0.005). Significant decreases in skin temperature, sweat rate, heart rate, and heat storage was also noted in the HI vs. the CO trials. Tolerance time in the HI exposure were longer than in the CO exposure (only 12 subjects in the CO trial endured the entire heat exposure session, as opposed to all 17 subjects in the HI group). It is concluded that hand immersion in cold water for 10 min is an effective method for decreasing the physiological strain caused by exercising under heat stress while wearing NBC protective garments. The method is convenient, simple, and allows longer working periods in hot or contaminated areas with shorter resting periods.

An Individualized, Perception-Based Protocol to Investigate Human Physiological Responses to Cooling

PubMed Central

Coolbaugh, Crystal L.; Bush, Emily C.; Galenti, Elizabeth S.; Welch, E. Brian; Towse, Theodore F.

2018-01-01

Cold exposure, a known stimulant of the thermogenic effects of brown adipose tissue (BAT), is the most widely used method to study BAT physiology in adult humans. Recently, individualized cooling has been recommended to standardize the physiological cold stress applied across participants, but critical experimental details remain unclear. The purpose of this work was to develop a detailed methodology for an individualized, perception-based protocol to investigate human physiological responses to cooling. Participants were wrapped in two water-circulating blankets and fitted with skin temperature probes to estimate BAT activity and peripheral vasoconstriction. We created a thermoesthesia graphical user interface (tGUI) to continuously record the subject's perception of cooling and shivering status during the cooling protocol. The protocol began with a 15 min thermoneutral phase followed by a series of 10 min cooling phases and concluded when sustained shivering (>1 min duration) occurred. Researchers used perception of cooling feedback (tGUI ratings) to manually adjust and personalize the water temperature at each cooling phase. Blanket water temperatures were recorded continuously during the protocol. Twelve volunteers (ages: 26.2 ± 1.4 years; 25% female) completed a feasibility study to evaluate the proposed protocol. Water temperature, perception of cooling, and shivering varied considerably across participants in response to cooling. Mean clavicle skin temperature, a surrogate measure of BAT activity, decreased (−0.99°C, 95% CI: −1.7 to −0.25°C, P = 0.16) after the cooling protocol, but an increase in supraclavicular skin temperature was observed in 4 participants. A strong positive correlation was also found between thermoesthesia and peripheral vasoconstriction (ρ = 0.84, P < 0.001). The proposed individualized, perception-based protocol therefore has potential to investigate the physiological responses to cold stress applied across populations with varying age, sex, body composition, and cold sensitivity characteristics. PMID:29593558

Effect of rapid warming of boar semen on sperm morphology and physiology.

PubMed

Bamba, K; Cran, D G

1985-09-01

The effect of rapid dilution (1:8 with BTS or 1:6.5 with KRP) and temperature change on sperm morphology and physiology were studied using boar spermatozoa pre-diluted in BF5 diluent. Rapid dilution of cold semen (5 degrees C) with a warm solution (37 degrees C) caused marked acrosomal changes which were most prominent in the anterior region. The acrosomal damage appeared to be caused mainly by rapid warming. In contrast to rapid cooling, rapid warming had little effect upon motility, glutamic-oxaloacetic transaminase release and respiration.

Repetitive cryotherapy attenuates the in vitro and in vivo mononuclear cell activation response.

PubMed

Lindsay, Angus; Othman, Mohd Izani; Prebble, Hannah; Davies, Sian; Gieseg, Steven P

2016-07-01

What is the central question of this study? Acute and repetitive cryotherapy are routinely used to accelerate postexercise recovery, although the effect on resident immune cells and repetitive exposure has largely been unexplored and neglected. What is the main finding and its importance? Using blood-derived mononuclear cells and semi-professional mixed martial artists, we show that acute and repetitive cryotherapy reduces the in vitro and in vivo T-cell and monocyte activation response whilst remaining independent of the physical performance of elite athletes. We investigated the effect of repetitive cryotherapy on the in vitro (cold exposure) and in vivo (cold water immersion) activation of blood-derived mononuclear cells following high-intensity exercise. Single and repeated cold exposure (5°C) of a mixed cell culture (T cells and monocytes) was investigated using in vitro tissue culture experimentation for total neopterin production (neopterin plus 7,8-dihydroneopterin). Fourteen elite mixed martial art fighters were also randomly assigned to either a cold water immersion (15 min at 10°C) or passive recovery protocol, which they completed three times per week during a 6 week training camp. Urine was collected and analysed for neopterin and total neopterin three times per week, and perceived soreness, fatigue, physical performance (broad jump, push-ups and pull-ups) and training performance were also assessed. Single and repetitive cold exposure significantly (P < 0.001) reduced total neopterin production from the mixed cell culture, whereas cold water immersion significantly (P < 0.05) attenuated urinary neopterin and total neopterin during the training camp without having any effect on physical performance parameters. Soreness and fatigue showed little variation between the groups, whereas training session performance was significantly (P < 0.05) elevated in the cold water immersion group. The data suggest that acute and repetitive cryotherapy attenuates in vitro T-cell and monocyte activation. This may explain the disparity in in vivo neopterin and total neopterin between cold water immersion and passive recovery following repetitive exposure during a high-intensity physical impact sport that remains independent of physical performance. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

The physiological response to cold-water immersion following a mixed martial arts training session.

PubMed

Lindsay, Angus; Carr, Sam; Cross, Sean; Petersen, Carl; Lewis, John G; Gieseg, Steven P

2017-05-01

Combative sport is one of the most physically intense forms of exercise, yet the effect of recovery interventions has been largely unexplored. We investigated the effect of cold-water immersion on structural, inflammatory, and physiological stress biomarkers following a mixed martial arts (MMA) contest preparation training session in comparison with passive recovery. Semiprofessional MMA competitors (n = 15) were randomly assigned to a cold-water immersion (15 min at 10 °C) or passive recovery protocol (ambient air) completed immediately following a contest preparation training session. Markers of muscle damage (urinary myoglobin), inflammation/oxidative stress (urinary neopterin + total neopterin (neopterin + 7,8-dihydroneopterin)), and hypothalamic-pituitary axis (HPA) activation (saliva cortisol) were determined before, immediately after, and 1, 2, and 24 h postsession. Ratings of perceived soreness and fatigue, counter movement jump, and gastrointestinal temperature were also measured. Concentrations of all biomarkers increased significantly (p < 0.05) postsession. Cold water immersion attenuated increases in urinary neopterin (p < 0.05, d = 0.58), total neopterin (p < 0.05, d = 0.89), and saliva cortisol after 2 h (p < 0.05, d = 0.68) and urinary neopterin again at 24 h (p < 0.01, d = 0.57) in comparison with passive recovery. Perceived soreness, fatigue, and gastrointestinal temperatures were also lower for the cold-water immersion group at several time points postsession whilst counter movement jump did not differ. Combative sport athletes who are subjected to impact-induced stress may benefit from immediate cold-water immersion as a simple recovery intervention that reduces delayed onset muscle soreness as well as macrophage and HPA activation whilst not impairing functional performance.

Effects of Melatonin on Anti-oxidative Systems and Photosystem II in Cold-Stressed Rice Seedlings

PubMed Central

Han, Qiao-Hong; Huang, Bo; Ding, Chun-Bang; Zhang, Zhong-Wei; Chen, Yang-Er; Hu, Chao; Zhou, Li-Jun; Huang, Yan; Liao, Jin-Qiu; Yuan, Shu; Yuan, Ming

2017-01-01

Melatonin (N-acetyl-5-methoxytryptamine) plays important role in multiple plant developmental processes and stress responses. We investigated the possible mediatory role of melatonin in growth, photosynthesis, and the response to cold stress in rice by using three different experiments: soaking seed; immersing roots, and spraying to leaves with 0, 20, or 100 μM melatonin. After 6 days of cold stress, the growth of rice seedlings was significantly inhibited, but this inhibition was alleviated by exogenous melatonin. Furthermore, exogenous melatonin pretreatment alleviated the accumulation of reactive oxygen species, malondialdehyde and cell death induced by cold stress. Melatonin pretreatment also relieved the stress-induced inhibitions to photosynthesis and photosystem II activities. Further investigations showed that, antioxidant enzyme activities and non-enzymatic antioxidant levels were increased by melatonin pretreatments. The treatment methods of seed soaking and root immersion were more effective in improving cold stress resistance than the spraying method. The results also indicated the dose-dependent response of melatonin on rice physiological, biochemical, and photosynthetic parameters. PMID:28553310

From genotype to phenotype: unraveling the complexities of cold adaptation in forest trees

Treesearch

Glenn T. Howe; Sally N. Aitken; David B. Neale; Kathleen D. Jermstad; Nicholas C. Wheeler; Tony H.H Chen

2003-01-01

Adaptation to winter cold in temperate and boreal trees involves complex genetic, physiological, and developmental processes. Genecological studies demonstrate the existence of steep genetic clines for cold adaptation traits in relation to environmental (mostly temperature related) gradients. Population differentiation is generally stronger for cold adaptation traits...

Could behaviour and not physiological thermal tolerance determine winter survival of aphids in cereal fields?

PubMed

Alford, Lucy; Andrade, Thiago Oliveira; Georges, Romain; Burel, Françoise; van Baaren, Joan

2014-01-01

Traits of physiological thermotolerance are commonly measured in the laboratory as predictors of the field success of ectotherms at unfavourable temperatures (e.g. during harsh winters, heatwaves, or under conditions of predicted global warming). Due to being more complicated to measure, behavioural thermoregulation is less commonly studied, although both physiology and behaviour interact to explain the survival of ectotherms. The aphids Metopolophium dirhodum, Rhopalosiphum padi and Sitobion avenae are commercially important pests of temperate cereal crops. Although coexisting, these species markedly differ in winter success, with R. padi being the most abundant species during cold winters, followed by S. avenae and lastly M. dirhodum. To better understand the thermal physiology and behavioural factors contributing to differential winter success, the lethal temperature (physiological thermotolerance) and the behaviour of aphids in a declining temperature regime (behavioural thermotolerance) of these three species were investigated. Physiological thermotolerance significantly differed between the three species, with R. padi consistently the least cold tolerant and S. avenae the most cold tolerant. However, although the least cold tolerant of the study species, significantly more R. padi remained attached to the host plant at extreme sub-zero temperatures than S. avenae and M. dirhodum. Given the success of anholocyclic R. padi in harsh winters compared to its anholocyclic counterparts, this study illustrates that behavioural differences could be more important than physiological thermotolerance in explaining resistance to extreme temperatures. Furthermore it highlights that there is a danger to studying physiological thermotolerance in isolation when ascertaining risks of ectotherm invasions, the establishment potential of exotic species in glasshouses, or predicting species impacts under climate change scenarios.

Inducing Cold-Sensitivity in the Frigophilic Fly Drosophila montana by RNAi

PubMed Central

Cook, Nicola; Tournière, Océane; Sneddon, Tanya; Ritchie, Michael G.

2016-01-01

Cold acclimation is a critical physiological adaptation for coping with seasonal cold. By increasing their cold tolerance individuals can remain active for longer at the onset of winter and can recover more quickly from a cold shock. In insects, despite many physiological studies, little is known about the genetic basis of cold acclimation. Recently, transcriptomic analyses in Drosophila virilis and D. montana revealed candidate genes for cold acclimation by identifying genes upregulated during exposure to cold. Here, we test the role of myo-inositol-1-phosphate synthase (Inos), in cold tolerance in D. montana using an RNAi approach. D. montana has a circumpolar distribution and overwinters as an adult in northern latitudes with extreme cold. We assessed cold tolerance of dsRNA knock-down flies using two metrics: chill-coma recovery time (CCRT) and mortality rate after cold acclimation. Injection of dsRNAInos did not alter CCRT, either overall or in interaction with the cold treatment, however it did induced cold-specific mortality, with high levels of mortality observed in injected flies acclimated at 5°C but not at 19°C. Overall, injection with dsRNAInos induced a temperature-sensitive mortality rate of over 60% in this normally cold-tolerant species. qPCR analysis confirmed that dsRNA injection successfully reduced gene expression of Inos. Thus, our results demonstrate the involvement of Inos in increasing cold tolerance in D. montana. The potential mechanisms involved by which Inos increases cold tolerance are also discussed. PMID:27832122

AFM of the ultrastructural and mechanical properties of lipid-raft-disrupted and/or cold-treated endothelial cells.

PubMed

Wu, Li; Huang, Jie; Yu, Xiaoxue; Zhou, Xiaoqing; Gan, Chaoye; Li, Ming; Chen, Yong

2014-02-01

The nonionic detergent extraction at 4 °C and the cholesterol-depletion-induced lipid raft disruption are the two widely used experimental strategies for lipid raft research. However, the effects of raft disruption and/or cold treatment on the ultrastructural and mechanical properties of cells are still unclear. Here, we evaluated the effects of raft disruption and/or cold (4 °C) treatment on these properties of living human umbilical vein endothelial cells (HUVECs). At first, the cholesterol-depletion-induced raft disruption was visualized by confocal microscopy and atomic force microscopy (AFM) in combination with fluorescent quantum dots. Next, the cold-induced cell contraction and the formation of end-branched filopodia were observed by confocal microscopy and AFM. Then, the cell-surface ultrastructures were imaged by AFM, and the data showed that raft disruption and cold treatment induced opposite effects on cell-surface roughness (a significant decrease and a significant increase, respectively). Moreover, the cell-surface mechanical properties (stiffness and adhesion force) of raft-disrupted- and/or cold-treated HUVECs were measured by the force measurement function of AFM. We found that raft disruption and cold treatment induced parallel effects on cell stiffness (increase) or adhesion force (decrease) and that the combination of the two treatments caused dramatically strengthened effects. Finally, raft disruption was found to significantly impair cell migration as previously reported, whereas temporary cold treatment only caused a slight but nonsignificant decrease in cell migration performed at physiological temperature. Although the mechanisms for causing these results might be complicated and more in-depth studies will be needed, our data may provide important information for better understanding the effects of raft disruption or cold treatment on cells and the two strategies for lipid raft research.

Cold tolerance and photosystem function in a montane red spruce population: physiological relationships with foliar carbohydrates

Treesearch

P.G. Schaberg; G.R. Strimbeck; G.J. Hawley; D.H. DeHayes; J.B. Shane; P.F. Murakami; T.D. Perkins; J.R. Donnelly; B.L. Wong

2000-01-01

Red spruce (Picea rubens Sarg.) growing in northern montane forests of eastern North America appears to be distinctive with respect to at least two aspects of winter physiology. First, red spruce attains only a modest level of midwinter cold tolerance compared to other north temperate conifers and appears barely capable of avoiding freezing injury at...

Order-picking in deep cold--physiological responses of younger and older females. Part 2: body core temperature and skin surface temperature.

PubMed

Baldus, Sandra; Kluth, Karsten; Strasser, Helmut

2012-01-01

So far, it was unclear to what extent working in deep cold-storage depots has an influence on female order-pickers body core temperature and skin surface temperature considering different age groups. Physiological effects of order-picking in a chill room (+3°C) and cold store (-24°C) were examined on 30 female subjects (Ss), classified in two age groups (20- to 35- year-olds and 40- to 65-year-olds). The body core temperature was taken every 15 min at the tympanum and the skin surface temperature was recorded continuously at seven different positions. Working in the chill room induced a decrease of the body core temperature up to 0.5K in comparison to the value at the outset for both age groups which could be compensated by all Ss during the breaks. Working in the cold store caused a decline up to 1.1K for the younger Ss and 1.3K for the older Ss. A complete warming-up during the breaks was often not possible. Regarding the skin surface temperature, working in the chill room can be considered as unproblematic, whereas significantly lower temperatures at nose, fingers and toes, associated with substantial negative subjective sensations, were recorded while working in the cold store.

The effects of fasting and cold exposure on metabolic rate and mitochondrial proton leak in liver and skeletal muscle of an amphibian, the cane toad Bufo marinus.

PubMed

Trzcionka, M; Withers, K W; Klingenspor, M; Jastroch, M

2008-06-01

Futile cycling of protons across the mitochondrial inner membrane contributes significantly to standard metabolic rate in a variety of ectothermic and endothermic animals, but adaptations of the mitochondrial bioenergetics to different environmental conditions have rarely been studied in ectotherms. Changes in ambient temperature and nutritional status have a great effect on the physiological demands of ectothermic amphibians and may require the adjustment of mitochondrial efficiency. In order to investigate the effect of temperature and nutritional status on the mitochondrial level, we exposed male cane toads to either 10 degrees C or 30 degrees C and fasted half of the animals in each group. Cold exposure resulted in a fourfold reduction of the resting metabolic rate whereas nutritional status had only minor effects. The mitochondrial adjustments to each condition were observed by comparing the proton leak kinetics of isolated liver and skeletal muscle mitochondria at 25 degrees C. In response to cold exposure, liver mitochondria showed a decrease in proton conductance while skeletal muscle mitochondria were unchanged. Additional food deprivation had minor effects in skeletal muscle, but in liver we uncovered surprising differences in energy saving mechanisms between the acclimation temperatures: in warm-acclimated toads, fasting resulted in a decrease of the proton conductance whereas in cold-acclimated toads, the activity of the respiratory chain was reduced. To investigate the molecular mechanism underlying mitochondrial proton leakage, we determined the adenine-nucleotide transporter (ANT) content, which explained tissue-specific differences in the basal proton leak, but neither the ANT nor uncoupling protein (UCP) gene expression correlated with alterations of the proton leak in response to physiological stimuli.

The effects of cold water immersion and active recovery on inflammation and cell stress responses in human skeletal muscle after resistance exercise.

PubMed

Peake, Jonathan M; Roberts, Llion A; Figueiredo, Vandre C; Egner, Ingrid; Krog, Simone; Aas, Sigve N; Suzuki, Katsuhiko; Markworth, James F; Coombes, Jeff S; Cameron-Smith, David; Raastad, Truls

2017-02-01

Cold water immersion and active recovery are common post-exercise recovery treatments. A key assumption about the benefits of cold water immersion is that it reduces inflammation in skeletal muscle. However, no data are available from humans to support this notion. We compared the effects of cold water immersion and active recovery on inflammatory and cellular stress responses in skeletal muscle from exercise-trained men 2, 24 and 48 h during recovery after acute resistance exercise. Exercise led to the infiltration of inflammatory cells, with increased mRNA expression of pro-inflammatory cytokines and neurotrophins, and the subcellular translocation of heat shock proteins in muscle. These responses did not differ significantly between cold water immersion and active recovery. Our results suggest that cold water immersion is no more effective than active recovery for minimizing the inflammatory and stress responses in muscle after resistance exercise. Cold water immersion and active recovery are common post-exercise recovery treatments. However, little is known about whether these treatments influence inflammation and cellular stress in human skeletal muscle after exercise. We compared the effects of cold water immersion versus active recovery on inflammatory cells, pro-inflammatory cytokines, neurotrophins and heat shock proteins (HSPs) in skeletal muscle after intense resistance exercise. Nine active men performed unilateral lower-body resistance exercise on separate days, at least 1 week apart. On one day, they immersed their lower body in cold water (10°C) for 10 min after exercise. On the other day, they cycled at a low intensity for 10 min after exercise. Muscle biopsies were collected from the exercised leg before, 2, 24 and 48 h after exercise in both trials. Exercise increased intramuscular neutrophil and macrophage counts, MAC1 and CD163 mRNA expression (P < 0.05). Exercise also increased IL1β, TNF, IL6, CCL2, CCL4, CXCL2, IL8 and LIF mRNA expression (P < 0.05). As evidence of hyperalgesia, the expression of NGF and GDNF mRNA increased after exercise (P < 0.05). The cytosolic protein content of αB-crystallin and HSP70 decreased after exercise (P < 0.05). This response was accompanied by increases in the cytoskeletal protein content of αB-crystallin and the percentage of type II fibres stained for αB-crystallin. Changes in inflammatory cells, cytokines, neurotrophins and HSPs did not differ significantly between the recovery treatments. These findings indicate that cold water immersion is no more effective than active recovery for reducing inflammation or cellular stress in muscle after a bout of resistance exercise. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Cold resistance depends on acclimation and behavioral caste in a temperate ant

NASA Astrophysics Data System (ADS)

Modlmeier, Andreas P.; Pamminger, Tobias; Foitzik, Susanne; Scharf, Inon

2012-10-01

Adjusting to low temperatures is important for animals living in cold environments. We studied the chill-coma recovery time in temperate ant workers ( Temnothorax nylanderi) from colonies collected in autumn and spring in Germany. We experimentally acclimated these ant colonies to cold temperatures followed by warm temperatures. As expected, cold-acclimated workers recovered faster from freezing temperatures, but subsequent heat acclimation did not change the short recovery times observed after cold acclimation. Hence, either heat acclimation improves cold tolerance, possibly as a general response to stress, or at least it does not negate enhanced cold tolerance following cold acclimation. Colonies collected in spring showed similar cold tolerance levels to cold-acclimated colonies in the laboratory. Next, we compared the chill-coma recovery time of different worker castes and found that exterior workers recovered faster than interior workers. This difference may be related to their more frequent exposure to cold, higher activity level, or distinct physiology. Interior workers were also heavier and showed a higher gaster-to-head ratio and thorax ratio compared to exterior workers. An obvious difference between exterior and interior workers is activity level, but we found no link between activity and cold tolerance. This suggests that physiology rather than behavioral differences could cause the increased cold tolerance of exterior workers. Our study reveals the importance of acclimation for cold tolerance under natural and standardized conditions and demonstrates differences in cold tolerance and body dimensions in monomorphic behavioral castes of an ant.

Physiological disturbances and overwinter mortality of largemouth bass from different latitudes.

PubMed

VanLandeghem, Matthew M; Wagner, Curtis P; Wahl, David H; Suski, Cory D

2013-01-01

Thermal conditions associated with winter can influence the distribution of a species. Because winter severity varies along latitudes, populations of temperate fish located along a latitudinal gradient may display variation in both sublethal and lethal responses to cold stressors. Sublethal physiological disturbances were quantified in age 1 largemouth bass (Micropterus salmoides) from populations originating from Alabama and Illinois but raised in a common environment. Fish were exposed to 6 h of rapid cold shock from 20° to 8°C (controls were held at 20°C) and then sampled for white muscle, whole blood, and plasma. After cold shock, glucose concentrations were elevated in Alabama but not Illinois fish. Sodium was lower and chloride was higher in Alabama largemouth bass, but fish from Illinois had a greater propensity for potassium loss during cold shock. In Illinois ponds, Alabama largemouth bass exhibited lower overwinter survival (adult: 10%; age 0: 22%) than did those from Illinois (adult: 80%; age 0: 82%). Latitudinal variation in physiological responses to cold stressors may therefore influence overwinter survival of largemouth bass and the ability of a fish species to exist over large geographic areas.

Comparing cold-stored and freshly lifted water oak (Quercus nigra) seedlings based on physiological parameters

Treesearch

Rosa C. Goodman; Kent G. Apostol; Douglass F. Jacobs; Barrett C. Wilson; Emile S. Gardiner

2007-01-01

Water oak is often used in afforestation projects in the Lower Mississippi Alluvial Valley, but its field performance is often poor due to low survival rates and severe top dieback immediately after planting. The poor physiological quality of planting stock may be a contributing factor to this transplanting problem. In this study, cold storage was investigated to...

Thyroid hormone regulates muscle function during cold acclimation in zebrafish (Danio rerio).

PubMed

Little, Alexander G; Seebacher, Frank

2013-09-15

Thyroid hormone (TH) is a universal regulator of growth, development and metabolism during cold exposure in mammals. In zebrafish (Danio rerio), TH regulates locomotor performance and metabolism during cold acclimation. The influence of TH on locomotor performance may be via its effect on metabolism or, as has been shown in mammals, by modulating muscle phenotypes. Our aim was to determine whether TH influences muscle phenotypes in zebrafish, and whether this could explain changes in swimming capacity in response to thermal acclimation. We used propylthiouracil and iopanoic acid to induce hypothyroidism in zebrafish over a 3-week acclimation period to either 18 or 28°C. To verify that physiological changes following hypothyroid treatment were in fact due to the action of TH, we supplemented hypothyroid fish with 3,5-diiodothryronine (T2) or 3,5,3'-triiodothyronine (T3). Cold-acclimated fish had significantly greater sustained swimming performance (Ucrit) but not burst speed. Greater Ucrit was accompanied by increased tail beat frequency, but there was no change in tail beat amplitude. Hypothyroidism significantly decreased Ucrit and burst performance, as well as tail beat frequency and SERCA activity in cold-acclimated fish. However, myofibrillar ATPase activity increased in cold-acclimated hypothyroid fish. Hypothyroid treatment also decreased mRNA concentrations of myosin heavy chain fast isoforms and SERCA 1 isoform in cold-acclimated fish. SERCA 1 mRNA increased in warm-acclimated hypothyroid fish, and SERCA 3 mRNA decreased in both cold- and warm-acclimated hypothyroid fish. Supplementation with either T2 or T3 restored Ucrit, burst speed, tail beat frequency, SERCA activity and myosin heavy chain and SERCA 1 and 3 mRNA levels of hypothyroid fish back to control levels. We show that in addition to regulating development and metabolism in vertebrates, TH also regulates muscle physiology in ways that affect locomotor performance in fish. We suggest that the role of TH in modulating SERCA1 expression during cold exposure may have predisposed it to regulate endothermic thermogenesis.

Reestablishment of ion homeostasis during chill-coma recovery in the cricket Gryllus pennsylvanicus

PubMed Central

MacMillan, Heath A.; Williams, Caroline M.; Staples, James F.; Sinclair, Brent J.

2012-01-01

The time required to recover from cold-induced paralysis (chill-coma) is a common measure of insect cold tolerance used to test central questions in thermal biology and predict the effects of climate change on insect populations. The onset of chill-coma in the fall field cricket (Gryllus pennsylvanicus, Orthoptera: Gryllidae) is accompanied by a progressive drift of Na+ and water from the hemolymph to the gut, but the physiological mechanisms underlying recovery from chill-coma are not understood for any insect. Using a combination of gravimetric methods and atomic absorption spectroscopy, we demonstrate that recovery from chill-coma involves a reestablishment of hemolymph ion content and volume driven by removal of Na+ and water from the gut. Recovery is associated with a transient elevation of metabolic rate, the time span of which increases with increasing cold exposure duration and closely matches the duration of complete osmotic recovery. Thus, complete recovery from chill-coma is metabolically costly and encompasses a longer period than is required for the recovery of muscle potentials and movement. These findings provide evidence that physiological mechanisms of hemolymph ion content and volume regulation, such as ion-motive ATPase activity, are instrumental in chill-coma recovery and may underlie natural variation in insect cold tolerance. PMID:23184963

[Assessment on the yield loss risk of longan caused by cold damage in South China].

PubMed

Zhao, Jun-fang; Yu, Hui-kang

2016-02-01

Using daily climate variables gathered from 64 meteorological stations in South China from 1961 to 2012, recognized hazard indicators about disaster grades of cold damage for longan, and methods on agricultural meteorological disasters risk and simulation technology, the yield loss risks of longan caused by cold damage in South China during different developmental periods were assessed. The results showed that during the period of physiologic differentiation of flower bud, the disasters of longan affected by mild cold damage in South China were the most common, followed by severe cold damage and moderate cold damage. The hazards caused by cold damage under different grades varied. In particular, under mild cold damage, light disaster of longan was found in Fujian, followed by Guangdong and Hainan, and Guangxi was serious. Under moderate cold damage, light disaster of longan was found in Hainan, followed by Guangdong and Guangxi, and Fujian was serious. Under severe cold damage, light disaster of longan was found in Hainan, followed by Guangdong and Guangxi, Fujian was serious. During the period of morphologic differentiation of flower bud, the disasters of longan affected by mild cold damage in South China were the most common, followed by severe cold damage and moderate cold damage, while the disasters of longan under mild, moderate and severe cold damages within this period were similar. Specifically, light disasters of longan were all found in Hainan, followed by Guangdong, Guangxi and Fujian. During the period of dormancy, the disaster of longan affected by mild cold damage in South China was the most common, followed by severe cold damage and moderate cold damage. Under mild and severe cold damage, light disaster of longan was found in Fujian, followed by Guangdong and Hainan, and Guangxi was serious. However, under moderate cold damage, light disaster of longan was found in Hainan and Guangxi, followed by Guangdong, and Fujian was serious. At the same level of hazard, the largest risk indices of yield loss of longan during different developmental stages significantly differed. Under mild cold damage, serious disasters of longan were found in the period of physiologic differentiation of flower bud, followed by the period of morphologic differentiation of flower bud and the period of dormancy. However, under moderate and severe cold damage, serious disasters of longan were found in the period of physiologic differentiation of flower bud, followed by the period of dormancy and the period of morphologic differentiation of flower bud.

Comparative proteomic analysis of seedling leaves of cold-tolerant and -sensitive spring soybean cultivars.

PubMed

Tian, Xin; Liu, Ying; Huang, Zhigang; Duan, Huaping; Tong, Jianhua; He, Xiaoling; Gu, Weihong; Ma, Hao; Xiao, Langtao

2015-03-01

Cold stress adversely affects the growth and development of seedling of spring soybean. Revealing responses in seedling to cold stress at proteomic level will help us to breed cold-tolerant spring soybean cultivars. In this study, to understand the responses, a proteomic analysis on the leaves of seedlings of one cold-tolerant soybean cultivar and one cold-sensitive soybean cultivar at 5°C for different times (12 and 24 h) was performed, with some proteomic results being further validated by physiological and biochemical analysis. Our results showed that 57 protein spots were found to be significantly changed in abundance and identified by MALDI-TOF/TOF MS. All the identified proteins were found to be involved in 13 metabolic pathways and cellular processes, including photosynthesis, protein folding and assembly, cell rescue and defense, cytoskeletal proteins, transcription and translation regulation, amino acid and nitrogen metabolism, protein degradation, storage proteins, signal transduction, carbohydrate metabolism, lipid metabolism, energy metabolism, and unknown. Based on the majority of the identified cold-responsive proteins, the effect of cold stress on seedling leaves of the two spring soybean cultivars was discussed. The reason that soybean cv. Guliqing is more cold-tolerant than soybean cv. Nannong 513 was due to its more protein, lipid and polyamine biosynthesis, more effective sulfur-containing metabolite recycling, and higher photosynthetic rate, as well as less ROS production and lower protein proteolysis and energy depletion under cold stress. Such a result will provide more insights into cold stress responses and for further dissection of cold tolerance mechanisms in spring soybean.

Physiological Acceptance Criteria for Cold Weather Clothing

DTIC Science & Technology

1991-04-01

subjective feelings of thermal comfort and temperature sensation were examined. Under many conditions that Navy cold weather clothing items are worn, it...is not practical to expect that the optimal level of thermal comfort can be obtained. Allowing for a moderate level of cold sensation and thermal

Physiological behavior of bean's seeds and grains during storage.

PubMed

Cassol, Flávia D R; Fortes, Andréa M T; Mendonça, Lorena C; Buturi, Camila V; Marcon, Thaís R

2016-05-31

Beans are one of the most used foods to meet the energy needs of the Brazilian diet, requiring farmers to use high seed physiological potential. The aim was to evaluate the physiological quality of beans stored for 360 days. Analyses were performed at 0, 30, 90, 180, 270, and 360 days after receiving the seeds (S1 and S2) and grains (G1 and G2) of BRS Splendor. Tests of germination, accelerated aging, cold, speed of germination, average length of shoots, and root were performed. The experimental design was completely randomized split-plot in time and the means were compared through Tukey test at 5% probability. Seed germination was not affected in S2, while the drop in S1 and G1 was significant. The vigor of grains from field 1 declined from 91 to 50% and from 93% to 76% by accelerated aging and cold, respectively, after 360 days. The germination speed tests performed showed a decreased during the experiment. The grains from field 1 had lower physiological quality. The accelerated aging and cold tests, through the speed of germination parameter, showed decrease in the vigor of the Splendor BRS. The storage period influenced the physiological quality of the beans tested.

Bibliography on Cold Regions Science and Technology. Volume 47, Part 1, 1993

DTIC Science & Technology

1993-09-01

54 refs. • DLC TP884.A3 D87 1989 Tundra. Plant ecology. Plant physiology. Plant tissues.tions. Biomass. ice cover effect. Ice optics. Algae. Concrete...1992. 89(1). p.24-31. 15 refs. ty. Chemical properties. Nuclear power. Freeze 91i92. This included providing the fundamental life Plante . P.. Pleau. R...Arora. R., etal, Plant physiology. Aug. 1992.99(4). photography. North Sea. Wetlands sewage treatment tested in the north. p. 1 56 2 .1568. 30 refs

The effect of low ambient temperature on the febrile responses of rats to semi-purified human endogenous pyrogen.

PubMed

Stitt, J T; Shimada, S G

1985-01-01

The febrile responses of Sprague-Dawley rats to semi-purified human endogenous pyrogen were studied at a thermoneutral ambient temperature (26 degrees C) and in the cold (3 degrees C). It was found that while rats developed typical monophasic febrile responses at thermoneutrality, febrile responses were absent in the cold-exposed rats. Experiments were conducted to determine whether this lack of febrile responses in cold-exposed rats was due to an inability of these animals to generate or retain heat in the cold. Thermogenesis and vasoconstriction were stimulated in cold-exposed rats by selectively cooling the hypothalamus, using chronically implanted thermodes. It was shown that, using this stimulus, metabolic rate could be increased by more than 50 percent and body temperature could be driven up at a rate of 5 degrees C/hour in rats exposed to the cold. Therefore, it was concluded that the lack of febrile responses of cold-exposed rats to pyrogen is in no way due to a physical or physiological inability to retain heat. Instead, it appears that in some manner cold exposure suppresses the sensitivity or responsiveness of the rat to pyrogenic stimuli.

Physiological and transcriptomic analyses reveal a response mechanism to cold stress in Santalum album L. leaves

PubMed Central

Zhang, Xinhua; Teixeira da Silva, Jaime A.; Niu, Meiyun; Li, Mingzhi; He, Chunmei; Zhao, Jinhui; Zeng, Songjun; Duan, Jun; Ma, Guohua

2017-01-01

Santalum album L. (Indian sandalwood) is an economically important plant species because of its ability to produce highly valued perfume oils. Little is known about the mechanisms by which S. album adapts to low temperatures. In this study, we obtained 100,445,724 raw reads by paired-end sequencing from S. album leaves. Physiological and transcriptomic changes in sandalwood seedlings exposed to 4 °C for 0–48 h were characterized. Cold stress induced the accumulation of malondialdehyde, proline and soluble carbohydrates, and increased the levels of antioxidants. A total of 4,424 differentially expressed genes were responsive to cold, including 3,075 cold-induced and 1,349 cold-repressed genes. When cold stress was prolonged, there was an increase in the expression of cold-responsive genes coding for transporters, responses to stimuli and stress, regulation of defense response, as well as genes related to signal transduction of all phytohormones. Candidate genes in the terpenoid biosynthetic pathway were identified, eight of which were significantly involved in the cold stress response. Gene expression analyses using qRT-PCR showed a peak in the accumulation of SaCBF2 to 4, 50-fold more than control leaves and roots following 12 h and 24 h of cold stress, respectively. The CBF-dependent pathway may play a crucial role in increasing cold tolerance. PMID:28169358

Using stimulation of the diving reflex in humans to teach integrative physiology.

PubMed

Choate, Julia K; Denton, Kate M; Evans, Roger G; Hodgson, Yvonne

2014-12-01

During underwater submersion, the body responds by conserving O2 and prioritizing blood flow to the brain and heart. These physiological adjustments, which involve the nervous, cardiovascular, and respiratory systems, are known as the diving response and provide an ideal example of integrative physiology. The diving reflex can be stimulated in the practical laboratory setting using breath holding and facial immersion in water. Our undergraduate physiology students complete a laboratory class in which they investigate the effects of stimulating the diving reflex on cardiovascular variables, which are recorded and calculated with a Finapres finger cuff. These variables include heart rate, cardiac output, stroke volume, total peripheral resistance, and arterial pressures (mean, diastolic, and systolic). Components of the diving reflex are stimulated by 1) facial immersion in cold water (15°C), 2) breathing with a snorkel in cold water (15°C), 3) facial immersion in warm water (30°C), and 4) breath holding in air. Statistical analysis of the data generated for each of these four maneuvers allows the students to consider the factors that contribute to the diving response, such as the temperature of the water and the location of the sensory receptors that initiate the response. In addition to providing specific details about the equipment, protocols, and learning outcomes, this report describes how we assess this practical exercise and summarizes some common student misunderstandings of the essential physiological concepts underlying the diving response. Copyright © 2014 The American Physiological Society.

A primer on clothing systems for cold-weather field work

USGS Publications Warehouse

Denner, J.C.

1993-01-01

Hypothermia in cold environments can be prevented by physiological adaptation and by the proper use of cold weather clothing. The human body adjusts to cold temperature by increasing the rates of basal metabolism, specific dynamic action, and physical exercise. Heat loss is reduced by vasoconstriction. Clothing systems for cold weather reduce loss by providing insulation and protection from the elements. Satisfactory cold- weather clothing is constructed of wool fabrics or the synthetic fibers polypropylene and polyester. Outerwear suitable for cold climates is insulated with down, high-loft polyester fiberfills, or the new synthetic thin insulators. (USGS)

Psychrophiles

NASA Astrophysics Data System (ADS)

Siddiqui, Khawar S.; Williams, Timothy J.; Wilkins, David; Yau, Sheree; Allen, Michelle A.; Brown, Mark V.; Lauro, Federico M.; Cavicchioli, Ricardo

2013-05-01

Psychrophilic (cold-adapted) microorganisms make a major contribution to Earth's biomass and perform critical roles in global biogeochemical cycles. The vast extent and environmental diversity of Earth's cold biosphere has selected for equally diverse microbial assemblages that can include archaea, bacteria, eucarya, and viruses. Underpinning the important ecological roles of psychrophiles are exquisite mechanisms of physiological adaptation. Evolution has also selected for cold-active traits at the level of molecular adaptation, and enzymes from psychrophiles are characterized by specific structural, functional, and stability properties. These characteristics of enzymes from psychrophiles not only manifest in efficient low-temperature activity, but also result in a flexible protein structure that enables biocatalysis in nonaqueous solvents. In this review, we examine the ecology of Antarctic psychrophiles, physiological adaptation of psychrophiles, and properties of cold-adapted proteins, and we provide a view of how these characteristics inform studies of astrobiology.

Brown adipose tissue activation is linked to distinct systemic effects on lipid metabolism in humans

USDA-ARS?s Scientific Manuscript database

Recent studies suggest that brown adipose tissue (BAT) plays a role in energy and glucose metabolism in humans. However, the physiological significance of human BAT in lipid metabolism remains unknown. We studied 16 overweight/obese men during prolonged, non-shivering cold and thermoneutral conditio...

Acute effects of local cold therapy in superficial burns on pain, in vivo microcirculation, edema formation and histomorphology.

PubMed

Altintas, B; Altintas, A A; Kraemer, R; Sorg, H; Vogt, P M; Altintas, M A

2014-08-01

Local cold therapy for burns is generally recommended to relief pain and limit tissue damage, however, there is limited data of its physiological benefit. This study aimed to evaluate pathophysiological effects of cold therapy in superficial burn on microcirculation, edema formation, and histomorphology. In 12 volunteers (8f, 4m; aged 30.4±14.1 years) circumscribed superficial burn was induced on both hand back and either left untreated as control (control-group) or treated by local-cold-application (cold-treatment-group). Prior to burn (t0), immediately (t1), 15 min (t2), and 30 min (t3) following cold therapy, following parameter was evaluated using intravital-microscopy; epidermal-thickness (ET), granular-cell-size (GCS), individual-blood-cell-flow (IBCF), and functional-capillary-density (FCD). Both ET and GCS increased significantly more in control-group and slightly in cold-treatment-group in t1, while turns to insignificant t2 onwards. IBCF and FCD raised up in control-group compared to dramatically decrease in cold-treatment-group in t1. In t2 both parameter remains in control-group and increased in cold-treatment-group. Comparison of both groups for IBCF and FCD indicates significant difference in t1 and t2, however, insignificant in t0 and t3. Microcirculation, edema formation, and histomorphology of superficial burn has been significantly influenced through immediate cold therapy, however, this alterations are transient and turns to ineffective after 30 min. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

Thermal acclimation mitigates cold-induced paracellular leak from the Drosophila gut.

PubMed

MacMillan, Heath A; Yerushalmi, Gil Y; Jonusaite, Sima; Kelly, Scott P; Donini, Andrew

2017-08-18

Chill susceptible insects suffer tissue damage and die at low temperatures. The mechanisms that cause chilling injury are not well understood but a growing body of evidence suggests that a cold-induced loss of ion and water homeostasis leads to hemolymph hyperkalemia that depolarizes cells, leading to cell death. The apparent root of this cascade is the net leak of osmolytes down their concentration gradients in the cold. Many insects, however, are capable of adjusting their thermal physiology, and cold-acclimated Drosophila can maintain homeostasis and avoid injury better than warm-acclimated flies. Here, we test whether chilling causes a loss of epithelial barrier function in female adult Drosophila, and provide the first evidence of cold-induced epithelial barrier failure in an invertebrate. Flies had increased rates of paracellular leak through the gut epithelia at 0 °C, but cold acclimation reduced paracellular permeability and improved cold tolerance. Improved barrier function was associated with changes in the abundance of select septate junction proteins and the appearance of a tortuous ultrastructure in subapical intercellular regions of contact between adjacent midgut epithelial cells. Thus, cold causes paracellular leak in a chill susceptible insect and cold acclimation can mitigate this effect through changes in the composition and structure of transepithelial barriers.

Effects of chronic environmental cold on growth, health, and select metabolic and immunologic responses of preruminant calves.

PubMed

Nonnecke, B J; Foote, M R; Miller, B L; Fowler, M; Johnson, T E; Horst, R L

2009-12-01

The physiological response of the preruminant calf to sustained exposure to moderate cold has not been studied extensively. Effects of cold on growth performance and health of preruminant calves as well as functional measures of energy metabolism, fat-soluble vitamin, and immune responsiveness were evaluated in the present study. Calves, 3 to 10 d of age, were assigned randomly to cold (n = 14) or warm (n = 15) indoor environments. Temperatures in the cold environment averaged 4.7 degrees C during the study. Frequent wetting of the environment and the calves was used to augment effects of the cold environment. Temperatures in the warm environment averaged 15.5 degrees C during the study. There was no attempt to increase the humidity in the warm environment. Preventative medications or vaccinations that might influence disease resistance were not administered. Nonmedicated milk replacer (20% crude protein and 20% fat fed at 0.45 kg/d) and a nonmedicated starter grain fed ad libitum were fed to all calves. Relative humidity was, on average, almost 10% higher in the cold environment. Warm-environment calves were moderately healthier (i.e., lower respiratory scores) and required less antibiotics. Scour scores, days scouring, and electrolyte costs, however, were unaffected by environmental temperature. Growth rates were comparable in warm and cold environments, although cold-environment calves consumed more starter grain and had lower blood glucose and higher blood nonesterified fatty acid concentrations. The nonesterified fatty acid and glucose values for cold-stressed calves, however, did not differ sufficiently from normal values to categorize these calves as being in a state of negative-energy balance. Levels of fat-soluble vitamin, antibody, tumor necrosis factor-alpha, and haptoglobin were unaffected by sustained exposure to moderate cold. These results support the contention that successful adaptation of the dairy calf to cold is dependent upon the availability of adequate nutrition.

Cholesterol-Independent Effects of Methyl-β-Cyclodextrin on Chemical Synapses

PubMed Central

Ormerod, Kiel G.; Coorssen, Jens R.; Mercier, A. Joffre

2012-01-01

The cholesterol chelating agent, methyl-β-cyclodextrin (MβCD), alters synaptic function in many systems. At crayfish neuromuscular junctions, MβCD is reported to reduce excitatory junctional potentials (EJPs) by impairing impulse propagation to synaptic terminals, and to have no postsynaptic effects. We examined the degree to which physiological effects of MβCD correlate with its ability to reduce cholesterol, and used thermal acclimatization as an alternative method to modify cholesterol levels. MβCD impaired impulse propagation and decreased EJP amplitude by 40% (P<0.05) in preparations from crayfish acclimatized to 14°C but not from those acclimatized to 21°C. The reduction in EJP amplitude in the cold-acclimatized group was associated with a 49% reduction in quantal content (P<0.05). MβCD had no effect on input resistance in muscle fibers but decreased sensitivity to the neurotransmitter L-glutamate in both warm- and cold-acclimatized groups. This effect was less pronounced and reversible in the warm-acclimatized group (90% reduction in cold, P<0.05; 50% reduction in warm, P<0.05). MβCD reduced cholesterol in isolated nerve and muscle from cold- and warm-acclimatized groups by comparable amounts (nerve: 29% cold, 25% warm; muscle: 20% cold, 18% warm; P<0.05). This effect was reversed by cholesterol loading, but only in the warm-acclimatized group. Thus, effects of MβCD on glutamate-sensitivity correlated with its ability to reduce cholesterol, but effects on impulse propagation and resulting EJP amplitude did not. Our results indicate that MβCD can affect both presynaptic and postsynaptic properties, and that some effects of MβCD are unrelated to cholesterol chelation. PMID:22590538

Influence of pyridostigmine bromide on human thermoregulation during cold-water immersion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cadarette, B.S.; Prusaczyk, W.K.; Sawka, M.N.

1991-03-11

This study examined the effects of an oral 30 mg dose of pyridostigmine bromide (PYR) on thermoregulatory and physiological responses during cold stress. Six men were immersed in chilled stirred water for up to 180 minutes; once 2 hours following ingestion of PYR and once 2 hours following ingestion of a placebo (CON). With PYR, mean ({plus minus} SD) red blood cell cholinesterase inhibition was 33 ({plus minus}12)% at 110 minutes post-ingestion. Cholinesterase inhibition was negatively related to lean body mass. Abdominal discomfort caused termination in 3 of 6 PYR experiments ({bar X} immersion time = 117 min) but inmore » no CON experiments ({bar X} immersion time = 142 min, p > 0.05). During immersion, metabolic rate increased significantly over pre-immersion levels, and increased with duration of immersion, but did not differ between conditions. PYR had no significant effect on rectal temperature, mean body temperature, thermal sensation, heart rate, or plasma cortisol concentration. It was concluded that a 30 mg dose of PYR does not increase susceptibility to hypothermia in humans immersed in cold-water; however, in combination with cold-stress, PYR may result in marked abdominal cramping and limit cold tolerance.« less

Climate change and temperature extremes: A review of heat- and cold-related morbidity and mortality concerns of municipalities.

PubMed

Gronlund, Carina J; Sullivan, Kyle P; Kefelegn, Yonathan; Cameron, Lorraine; O'Neill, Marie S

2018-08-01

Cold and hot weather are associated with mortality and morbidity. Although the burden of temperature-associated mortality may shift towards high temperatures in the future, cold temperatures may represent a greater current-day problem in temperate cities. Hot and cold temperature vulnerabilities may coincide across several personal and neighborhood characteristics, suggesting opportunities for increasing present and future resilience to extreme temperatures. We present a narrative literature review encompassing the epidemiology of cold- and heat-related mortality and morbidity, related physiologic and environmental mechanisms, and municipal responses to hot and cold weather, illustrated by Detroit, Michigan, USA, a financially burdened city in an economically diverse metropolitan area. The Detroit area experiences sharp increases in mortality and hospitalizations with extreme heat, while cold temperatures are associated with more gradual increases in mortality, with no clear threshold. Interventions such as heating and cooling centers may reduce but not eliminate temperature-associated health problems. Furthermore, direct hemodynamic responses to cold, sudden exertion, poor indoor air quality and respiratory epidemics likely contribute to cold-related mortality. Short- and long-term interventions to enhance energy and housing security and housing quality may reduce temperature-related health problems. Extreme temperatures can increase morbidity and mortality in municipalities like Detroit that experience both extreme heat and prolonged cold seasons amidst large socioeconomic disparities. The similarities in physiologic and built-environment vulnerabilities to both hot and cold weather suggest prioritization of strategies that address both present-day cold and near-future heat concerns. Copyright © 2018. Published by Elsevier B.V.

Ice age fish in a warming world: minimal variation in thermal acclimation capacity among lake trout (Salvelinus namaycush) populations

PubMed Central

Kelly, Nicholas I.; Burness, Gary; McDermid, Jenni L.; Wilson, Chris C.

2014-01-01

In the face of climate change, the persistence of cold-adapted species will depend on their adaptive capacity for physiological traits within and among populations. The lake trout (Salvelinus namaycush) is a cold-adapted salmonid and a relict from the last ice age that is well suited as a model species for studying the predicted effects of climate change on coldwater fishes. We investigated the thermal acclimation capacity of upper temperature resistance and metabolism of lake trout from four populations across four acclimation temperatures. Individuals were reared from egg fertilization onward in a common environment and, at 2 years of age, were acclimated to 8, 11, 15 or 19°C. Although one population had a slightly higher maximal metabolic rate (MMR), higher metabolic scope for activity and faster metabolic recovery across all temperatures, there was no interpopulation variation for critical thermal maximum (CTM) or routine metabolic rate (RMR) or for the thermal acclimation capacity of CTM, RMR, MMR or metabolic scope. Across the four acclimation temperatures, there was a 3°C maximal increase in CTM and 3-fold increase in RMR for all populations. Above 15°C, a decline in MMR and increase in RMR resulted in sharply reduced metabolic scope for all populations acclimated at 19°C. Together, these data suggest there is limited variation among lake trout populations in thermal physiology or capacity for thermal acclimatization, and that climate change may impact lake trout populations in a similar manner across a wide geographical range. Understanding the effect of elevated temperatures on the thermal physiology of this economically and ecologically important cold-adapted species will help inform management and conservation strategies for the long-term sustainability of lake trout populations. PMID:27293646

Polar Marine Microorganisms and Climate Change.

PubMed

Verde, C; Giordano, D; Bellas, C M; di Prisco, G; Anesio, A M

2016-01-01

The large diversity of marine microorganisms harboured by oceans plays an important role in planet sustainability by driving globally important biogeochemical cycles; all primary and most secondary production in the oceans is performed by microorganisms. The largest part of the planet is covered by cold environments; consequently, cold-adapted microorganisms have crucial functional roles in globally important environmental processes and biogeochemical cycles cold-adapted extremophiles are a remarkable model to shed light on the molecular basis of survival at low temperature. The indigenous populations of Antarctic and Arctic microorganisms are endowed with genetic and physiological traits that allow them to live and effectively compete at the temperatures prevailing in polar regions. Some genes, e.g. glycosyltransferases and glycosylsynthetases involved in the architecture of the cell wall, may have been acquired/retained during evolution of polar strains or lost in tropical strains. This present work focusses on temperature and its role in shaping microbial adaptations; however, in assessing the impacts of climate changes on microbial diversity and biogeochemical cycles in polar oceans, it should not be forgotten that physiological studies need to include the interaction of temperature with other abiotic and biotic factors. © 2016 Elsevier Ltd All rights reserved.

Proteomic Characterization of Inbreeding-Related Cold Sensitivity in Drosophila melanogaster

PubMed Central

Beck, Hans C.; Petersen, Jørgen; Gagalova, Kristina Kirilova; Loeschcke, Volker

2013-01-01

Inbreeding depression is a widespread phenomenon of central importance to agriculture, medicine, conservation biology and evolutionary biology. Although the population genetic principles of inbreeding depression are well understood, we know little about its functional genomic causes. To provide insight into the molecular interplay between intrinsic stress responses, inbreeding depression and temperature tolerance, we performed a proteomic characterization of a well-defined conditional inbreeding effect in a single line of Drosophila melanogaster, which suffers from extreme cold sensitivity and lethality. We identified 48 differentially expressed proteins in a conditional lethal line as compared to two control lines. These proteins were enriched for proteins involved in hexose metabolism, in particular pyruvate metabolism, and many were found to be associated with lipid particles. These processes can be linked to known cold tolerance mechanisms, such as the production of cryoprotectants, membrane remodeling and the build-up of energy reserves. We checked mRNA-expression of seven genes with large differential protein expression. Although protein expression poorly correlated with gene expression, we found a single gene (CG18067) that, after cold shock, was upregulated in the conditional lethal line both at the mRNA and protein level. Expression of CG18067 also increased in control flies after cold shock, and has previously been linked to cold exposure and chill coma recovery time. Many differentially expressed proteins in our study appear to be involved in cold tolerance in non-inbred individuals. This suggest the conditional inbreeding effect to be caused by misregulation of physiological cold tolerance mechanisms. PMID:23658762

Physiological responses to acute cold exposure in young lean men

PubMed Central

Martinez-Tellez, Borja; Sanchez-Delgado, Guillermo; A. Alcantara, Juan M.; Acosta-Manzano, Pedro; Morales-Artacho, Antonio J.; R. Ruiz, Jonatan

2018-01-01

The aim of this study was to comprehensively describe the physiological responses to an acute bout of mild cold in young lean men (n = 11, age: 23 ± 2 years, body mass index: 23.1 ± 1.2 kg/m2) to better understand the underlying mechanisms of non-shivering thermogenesis and how it is regulated. Resting energy expenditure, substrate metabolism, skin temperature, thermal comfort perception, superficial muscle activity, hemodynamics of the forearm and abdominal regions, and heart rate variability were measured under warm conditions (22.7 ± 0.2°C) and during an individualized cooling protocol (air-conditioning and water cooling vest) in a cold room (19.4 ± 0.1°C). The temperature of the cooling vest started at 16.6°C and decreased ~ 1.4°C every 10 minutes until participants shivered (93.5 ± 26.3 min). All measurements were analysed across 4 periods: warm period, at 31% and at 64% of individual´s cold exposure time until shivering occurred, and at the shivering threshold. Energy expenditure increased from warm period to 31% of cold exposure by 16.7% (P = 0.078) and to the shivering threshold by 31.7% (P = 0.023). Fat oxidation increased by 72.6% from warm period to 31% of cold exposure (P = 0.004), whereas no changes occurred in carbohydrates oxidation. As shivering came closer, the skin temperature and thermal comfort perception decreased (all P<0.05), except in the supraclavicular skin temperature, which did not change (P>0.05). Furthermore, the superficial muscle activation increased at the shivering threshold. It is noteworthy that the largest physiological changes occurred during the first 30 minutes of cold exposure, when the participants felt less discomfort. PMID:29734360

Extensive Variation in Fried Chip Color and Tuber Composition in Cold-Stored Tubers of Wild Potato (Solanum) Germplasm

USDA-ARS?s Scientific Manuscript database

Cold-induced sweetening and browning in the Maillard reaction have driven extensive research in the areas of plant physiology, biochemistry, and food science in Solanum tuberosum. To date, research in these areas excluded wild relatives of potato. This is the first assessment of cold-stored tuber c...

Cold pressor test in spinal cord injury-revisited.

PubMed

Hubli, Michèle; Bolt, Doris; Krassioukov, Andrei V

2018-06-01

Systematic review. A spinal cord injury (SCI) commonly results in alterations of cardiovascular physiology. In order to investigate such alterations, the cold pressor test (CPT) has been used as an established challenge test. This review summarizes the basic physiology underlying a CPT, discusses potential mechanisms responsible for abnormal pressor responses following SCI, and highlights the utility of CPT in the SCI population. Canada and Switzerland. We have completed a comprehensive review of studies that have investigated the effect of foot or hand CPT on hemodynamic indices in individuals with SCI. Depending on the level of spinal cord lesion and the location of cold application, i.e., above or below the lesion, mean arterial pressure typically increases (ranging between 4 and 23 mmHg), while heart rate responses demonstrated either a decrease or an increase (ranging between -4 and 24 bpm) during CPT. The increase in blood pressure during foot CPT in high-level lesions might not necessarily be attributed to a physiological CPT response as seen in able-bodied individuals, but rather due to a reflexic sympathetic discharge below the level of lesion, known as autonomic dysreflexia. Further investigations in a wider range of individuals with SCI including incomplete injuries might be helpful to examine the ability of CPT assessing the integrity of the autonomic nervous system following SCI. Furthermore, additional autonomic tests are needed to emphasize the integrity of autonomic pathways and to account for the complexity of the autonomic nervous system.

The ins and outs of water dynamics in cold tolerant soil invertebrates.

PubMed

Holmstrup, Martin

2014-10-01

Many soil invertebrates have physiological characteristics in common with freshwater animals and represent an evolutionary transition from aquatic to terrestrial life forms. Their high cuticular permeability and ability to tolerate large modifications of internal osmolality are of particular importance for their cold tolerance. A number of cold region species that spend some or most of their life-time in soil are in more or less intimate contact with soil ice during overwintering. Unless such species have effective barriers against cuticular water-transport, they have only two options for survival: tolerate internal freezing or dehydrate. The risk of internal ice formation may be substantial due to inoculative freezing and many species rely on freeze-tolerance for overwintering. If freezing does not occur, the desiccating power of external ice will cause the animal to dehydrate until vapor pressure equilibrium between body fluids and external ice has been reached. This cold tolerance mechanism is termed cryoprotective dehydration (CPD) and requires that the animal must be able to tolerate substantial dehydration. Even though CPD is essentially a freeze-avoidance strategy the associated physiological traits are more or less the same as those found in freeze tolerant species. The most well-known are accumulation of compatible osmolytes and molecular chaperones reducing or protecting against the stress caused by cellular dehydration. Environmental moisture levels of the habitat are important for which type of cold tolerance is employed, not only in an evolutionary context, but also within a single population. Some species use CPD under relatively dry conditions, but freeze tolerance when soil moisture is high. Copyright © 2014 Elsevier Ltd. All rights reserved.

Physiological response and microRNA expression profiles in head kidney of genetically improved farmed tilapia (GIFT, Oreochromis niloticus) exposed to acute cold stress.

PubMed

Qiang, Jun; Cui, Yan T; Tao, Fan Y; Bao, Wen J; He, Jie; Li, Xia H; Xu, Pao; Sun, Lan Y

2018-01-09

Cold stress has a serious impact on the overwintering survival and yield of genetically improved farmed tilapia (GIFT, Oreochromis niloticus). Understanding the physiological and molecular regulation mechanisms of low-temperature adaptation is necessary to help breed new tolerant strains. The semi-lethal low temperature of juvenile GIFT at 96 h was determined as 9.4 °C. We constructed and sequenced two small RNA libraries from head kidney tissues, one for the control (CO) group and one for the 9.4 °C-stressed (LTS) group, and identified 1736 and 1481 known microRNAs (miRNAs), and 164 and 152 novel miRNAs in the CO and LTS libraries, respectively. We verify the expression of nine up-regulated miRNAs and eight down-regulation miRNAs by qRT-PCR, and found their expression patterns were consistent with the sequencing results. We found that cold stress may have produced dysregulation of free radical and lipid metabolism, decreased superoxide dismutase activity, reduced respiratory burst and phagocytic activity of macrophages, increased malondialdehyde content, and adversely affected the physiological adaptation of GIFT, eventually leading to death. This study revealed interactions among miRNAs and signal regulated pathways in GIFT under cold stress that may help to understand the pathways involved in cold resistance.

Storage temperature and 1-MCP treatment affect storage disorders and physiological attributes of ‘Royal Gala’ apples

USDA-ARS?s Scientific Manuscript database

‘Royal Gala’ apples [Malus domestica (Borkh.) Mansf.] can develop postharvest disorders such as flesh browning, senescent breakdown, peeling, cracking, or shriveling during and after cold storage. The objective of this study was to examine the effects of storage temperature and a range of 1-methylc...

Cold and Heat Stress Diversely Alter Both Cauliflower Respiration and Distinct Mitochondrial Proteins Including OXPHOS Components and Matrix Enzymes

PubMed Central

Rurek, Michał; Czołpińska, Magdalena; Pawłowski, Tomasz Andrzej; Krzesiński, Włodzimierz; Spiżewski, Tomasz

2018-01-01

Complex proteomic and physiological approaches for studying cold and heat stress responses in plant mitochondria are still limited. Variations in the mitochondrial proteome of cauliflower (Brassica oleracea var. botrytis) curds after cold and heat and after stress recovery were assayed by two-dimensional polyacrylamide gel electrophoresis (2D PAGE) in relation to mRNA abundance and respiratory parameters. Quantitative analysis of the mitochondrial proteome revealed numerous stress-affected protein spots. In cold, major downregulations in the level of photorespiratory enzymes, porine isoforms, oxidative phosphorylation (OXPHOS) and some low-abundant proteins were observed. In contrast, carbohydrate metabolism enzymes, heat-shock proteins, translation, protein import, and OXPHOS components were involved in heat response and recovery. Several transcriptomic and metabolic regulation mechanisms are also suggested. Cauliflower plants appeared less susceptible to heat; closed stomata in heat stress resulted in moderate photosynthetic, but only minor respiratory impairments, however, photosystem II performance was unaffected. Decreased photorespiration corresponded with proteomic alterations in cold. Our results show that cold and heat stress not only operate in diverse modes (exemplified by cold-specific accumulation of some heat shock proteins), but exert some associations at molecular and physiological levels. This implies a more complex model of action of investigated stresses on plant mitochondria. PMID:29547512

Cold habituation does not improve manual dexterity during rest and exercise in 5 °C

NASA Astrophysics Data System (ADS)

Muller, Matthew D.; Seo, Yongsuk; Kim, Chul-Ho; Ryan, Edward J.; Pollock, Brandon S.; Burns, Keith J.; Glickman, Ellen L.

2014-04-01

When exposed to a cold environment, a barehanded person experiences pain, cold sensation, and reduced manual dexterity. Both acute (e.g. exercise) and chronic (e.g. cold acclimatization or habituation) processes might lessen these negative effects. The purpose of this experiment was to determine the effect of cold habituation on physiology, perception, and manual dexterity during rest, exercise, and recovery in 5 °C. Six cold weather athletes (CWA) and eight non habituated men (NON) volunteered to participate in a repeated measures cross-over design. The protocol was conducted in 5 °C and was 90 min of resting cold exposure, 30 min of cycle ergometry exercise (50 % VO2 peak), and 60 min of seated recovery. Core and finger skin temperature, metabolic rate, Purdue Pegboard dexterity performance, hand pain, thermal sensation, and mood were quantified. Exercise-induced finger rewarming (EIFRW) was calculated for each hand. During 90 min of resting exposure to 5 °C, the CWA had a smaller reduction in finger temperature, a lower metabolic rate, less hand pain, and less negative mood. Despite this cold habituation, dexterity performance was not different between groups. In response to cycle ergometry, EIFRW was greater in CWA (~12 versus 7 °C) and occurred at lower core temperatures (37.02 versus 37.31 °C) relative to NON but dexterity was not greater during post-exercise recovery. The current data indicate that cold habituated men (i.e., CWA) do not perform better on the Purdue Pegboard during acute cold exposure. Furthermore, despite augmented EIFRW in CWA, dexterity during post-exercise recovery was similar between groups.

Global analysis of gene expression in maize leaves treated with low temperature. II. Combined effect of severe cold (8 °C) and circadian rhythm.

PubMed

Jończyk, M; Sobkowiak, A; Trzcinska-Danielewicz, J; Skoneczny, M; Solecka, D; Fronk, J; Sowiński, P

2017-10-01

In maize seedlings, severe cold results in dysregulation of circadian pattern of gene expression causing profound modulation of transcription of genes related to photosynthesis and other key biological processes. Plants live highly cyclic life and their response to environmental stresses must allow for underlying biological rhythms. To study the interplay of a stress and a rhythmic cue we investigated transcriptomic response of maize seedlings to low temperature in the context of diurnal gene expression. Severe cold stress had pronounced effect on the circadian rhythm of a substantial proportion of genes. Their response was strikingly dual, comprising either flattening (partial or complete) of the diel amplitude or delay of expression maximum/minimum by several hours. Genes encoding central oscillator components behaved in the same dual manner, unlike their Arabidopsis counterparts reported earlier to cease cycling altogether upon cold treatment. Also numerous genes lacking circadian rhythm responded to the cold by undergoing up- or down-regulation. Notably, the transcriptome changes preceded major physiological manifestations of cold stress. In silico analysis of metabolic processes likely affected by observed gene expression changes indicated major down-regulation of photosynthesis, profound and multifarious modulation of plant hormone levels, and of chromatin structure, transcription, and translation. A role of trehalose and stachyose in cold stress signaling was also suggested. Meta-analysis of published transcriptomic data allowed discrimination between general stress response of maize and that unique to severe cold. Several cis- and trans-factors likely involved in the latter were predicted, albeit none of them seemed to have a major role. These results underscore a key role of modulation of diel gene expression in maize response to severe cold and the unique character of the cold-response of the maize circadian clock.

Seed dormancy in alpine species

PubMed Central

Schwienbacher, Erich; Navarro-Cano, Jose Antonio; Neuner, Gilbert; Erschbamer, Brigitta

2011-01-01

In alpine species the classification of the various mechanisms underlying seed dormancy has been rather questionable and controversial. Thus, we investigated 28 alpine species to evaluate the prevailing types of dormancy. Embryo type and water impermeability of seed coats gave an indication of the potential seed dormancy class. To ascertain the actual dormancy class and level, we performed germination experiments comparing the behavior of seeds without storage, after cold-dry storage, after cold-wet storage, and scarification. We also tested the light requirement for germination in some species. Germination behavior was characterized using the final germination percentage and the mean germination time. Considering the effects of the pretreatments, a refined classification of the prevailing dormancy types was constructed based on the results of our pretreatments. Only two out of the 28 species that we evaluated had predominantly non-dormant seeds. Physiological dormancy was prevalent in 20 species, with deep physiological dormancy being the most abundant, followed by non-deep and intermediate physiological dormancy. Seeds of four species with underdeveloped embryos were assigned to the morphophysiologial dormancy class. An impermeable seed coat was identified in two species, with no additional physiological germination block. We defined these species as having physical dormancy. Light promoted the germination of seeds without storage in all but one species with physiological dormancy. In species with physical dormancy, light responses were of minor importance. We discuss our new classification in the context of former germination studies and draw implications for the timing of germination in the field. PMID:24415831

Body size as a latent variable in a structural equation model: thermal acclimation and energetics of the leaf-eared mouse.

PubMed

Nespolo, Roberto F; Arim, Matías; Bozinovic, Francisco

2003-07-01

Body size is one of the most important determinants of energy metabolism in mammals. However, the usual physiological variables measured to characterize energy metabolism and heat dissipation in endotherms are strongly affected by thermal acclimation, and are also correlated among themselves. In addition to choosing the appropriate measurement of body size, these problems create additional complications when analyzing the relationships among physiological variables such as basal metabolism, non-shivering thermogenesis, thermoregulatory maximum metabolic rate and minimum thermal conductance, body size dependence, and the effect of thermal acclimation on them. We measured these variables in Phyllotis darwini, a murid rodent from central Chile, under conditions of warm and cold acclimation. In addition to standard statistical analyses to determine the effect of thermal acclimation on each variable and the body-mass-controlled correlation among them, we performed a Structural Equation Modeling analysis to evaluate the effects of three different measurements of body size (body mass, m(b); body length, L(b) and foot length, L(f)) on energy metabolism and thermal conductance. We found that thermal acclimation changed the correlation among physiological variables. Only cold-acclimated animals supported our a priori path models, and m(b) appeared to be the best descriptor of body size (compared with L(b) and L(f)) when dealing with energy metabolism and thermal conductance. However, while m(b) appeared to be the strongest determinant of energy metabolism, there was an important and significant contribution of L(b) (but not L(f)) to thermal conductance. This study demonstrates how additional information can be drawn from physiological ecology and general organismal studies by applying Structural Equation Modeling when multiple variables are measured in the same individuals.

Effect of intravenous infusion of a beta-adrenergic blocking agent on the haemodynamic changes in human masseter muscle induced by cold-pressor stimulation.

PubMed

Maekawa, K; Kuboki, T; Miyawaki, T; Shimada, M; Yamashita, A; Clark, G T

1999-06-01

Eight healthy non-smoking males (mean age: 24.1 +/- 1.1 years) without any history of chronic muscle pain and migraine participated in this study. Haemoglobin (Hb) and oxygen (O2) saturation in the right masseter muscle were continuously recorded with a non-invasive near-infrared spectroscopic device. Heart rate and blood pressure were also recorded. The experiment had three phases: a placebo drug (physiological saline) with cold-pressor trial, a 30-sec maximal voluntary clenching (MVC) trial, and a propranolol with cold-pressor trial. The saline and drug trials each involved continuous recording for 1 min before, 2 min during and 5 min after the cold-pressor stimulation (4 degrees C). Physiological saline (20 ml) or propranolol hydrochloride (20 ml) were infused at the rate of 2 ml/min. This infusion was begun 20 min before the baseline recording and participants did not know which solution (saline or propranolol) was being infused. For the MVC trial, each participant was asked to perform a 30-sec clench of their jaw-closing muscles. There was a rest period of 15 min between each trial. The individual Hb and O2 data were normalized so that the baseline at the beginning of the experiment was equal to zero, and the Hb and O2 data were normalized as a percentage of the individual's own highest absolute Hb and O2 after and during the MVC, respectively. The results showed that the mean baseline Hb 1 min before cold-pressor stimulation was significantly lower in the beta-blocker trial than in the placebo trial (p = 0.035). The mean change in Hb from baseline during cold-pressor stimulation in the beta-blocker trial was also significantly less than in the placebo trial (p = 0.035). The mean Hb rebound change after the cold-pressor stimulation in the beta-blocker trial was significantly higher than in the placebo trial, and no significant heart-rate differences were observed in the period after cold-pressor stimulation. Overall, the mean heart rate before and during that stimulation was significantly lower in the beta-blocker trial than the placebo trial (p < 0.001). There was no significant mean blood-pressure difference between placebo and beta-blocker trials at any time. These results suggest that beta-adrenoceptor blocking decreases the blood volume in the resting masseter, suppresses the incremental blood-volume change during cold-pressor stimulation, and discloses a hidden vasoconstrictive effect after that stimulation.

Temperature and photoperiod as environmental cues affect body mass and thermoregulation in Chinese bulbuls, Pycnonotus sinensis.

PubMed

Hu, Shi-Nan; Zhu, Ying-Yang; Lin, Lin; Zheng, Wei-Hong; Liu, Jin-Song

2017-03-01

Seasonal changes in temperature and photoperiod are important environmental cues used by small birds to adjust their body mass ( M b ) and thermogenesis. However, the relative importance of these cues with respect to seasonal adjustments in M b and thermogenesis is difficult to distinguish. In particular, the effects of temperature and photoperiod on energy metabolism and thermoregulation are not well known in many passerines. To address this problem, we measured the effects of temperature and photoperiod on M b , energy intake, resting metabolic rate (RMR), organ mass and physiological and biochemical markers of metabolic activity in the Chinese bulbul ( Pycnonotus sinensis ). Groups of Chinese bulbuls were acclimated in a laboratory to the following conditions: (1) warm and long photoperiod, (2) warm and short photoperiod, (3) cold and long photoperiod, and (4) cold and short photoperiod, for 4 weeks. The results indicate that Chinese bulbuls exhibit adaptive physiological regulation when exposed to different temperatures and photoperiods. M b , RMR, gross energy intake and digestible energy intake were higher in cold-acclimated than in warm-acclimated bulbuls, and in the short photoperiod than in the long photoperiod. The resultant flexibility in energy intake and RMR allows Chinese bulbuls exposed to different temperatures and photoperiods to adjust their energy balance and thermogenesis accordingly. Cold-acclimated birds had heightened state-4 respiration and cytochrome c oxidase activity in their liver and muscle tissue compared with warm-acclimated birds indicating the cellular mechanisms underlying their adaptive thermogenesis. Temperature appears to be a primary cue for adjusting energy budget and thermogenic ability in Chinese bulbuls; photoperiod appears to intensify temperature-induced changes in energy metabolism and thermoregulation. © 2017. Published by The Company of Biologists Ltd.

Utilization of the organ care system as ex-vivo lung perfusion after cold storage transportation.

PubMed

Mohite, P N; Maunz, O; Popov, A-F; Zych, B; Patil, N P; Simon, A R

2015-11-01

The Organ Care System (OCS) allows perfusion and ventilation of the donor lungs under physiological conditions. Ongoing trials to compare preservation with OCS Lung with standard cold storage do not include donor lungs with suboptimal gas exchange and donor lungs treated with OCS following cold storage transportation. We present a case of a 48-yr-old man who received such lungs after cold storage transportation treated with ex-vivo lung perfusion utilizing OCS. © The Author(s) 2015.

Changes in ventricular function during emotional stress and cold exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiess, M.C.; Moore, R.A.; Dimsdale, J.

1984-01-01

Patients with cardiac disease frequently develop symptoms with emotional stress or cold exposure. To investigate the effects of these stresses in normal subjects, an ambulatory ventricular function monitor (VEST) (previously reported to measure EFs which correlate well with gamma camera measurements) was employed to record sequential 2 minute time activity curves from the left ventricles of 6 healthy men (ages 19-24) during a control period and during a 30 minute stress interview with a psychiatrist. Four of the subjects were also monitored in a cold room (1/sup 0/C) for 20 min. In addition to the left ventricular time-activity curve, heartmore » rate (HR), and BP (cuff) were recorded. All subjects had increases in HR, BP and EF during the stress interview. Cold, however, produced decreases in HR and EF and an increase in BP. The results (mean +- SD) are tabulated. End-systolic and end-diastolic counts and hence volume decreased during the interview and increased during cold exposure. The results suggest that (1) ambulatory changes in ventricular function can be measured with the VEST, and (2) significant changes in cardiovascular physiology are seen in normal subjects during a stress interview and exposure to cold.« less

Combined ocean acidification and low temperature stressors cause coral mortality

NASA Astrophysics Data System (ADS)

Kavousi, Javid; Parkinson, John Everett; Nakamura, Takashi

2016-09-01

Oceans are predicted to become more acidic and experience more temperature variability—both hot and cold—as climate changes. Ocean acidification negatively impacts reef-building corals, especially when interacting with other stressors such as elevated temperature. However, the effects of combined acidification and low temperature stress have yet to be assessed. Here, we exposed nubbins of the scleractinian coral Montipora digitata to ecologically relevant acidic, cold, or combined stress for 2 weeks. Coral nubbins exhibited 100% survival in isolated acidic and cold treatments, but ~30% mortality under combined conditions. These results provide further evidence that coupled stressors have an interactive effect on coral physiology, and reveal that corals in colder environments are also susceptible to the deleterious impacts of coupled ocean acidification and thermal stress.

Information services for comparative analysis of biorhythm research

NASA Technical Reports Server (NTRS)

1972-01-01

References and full text documents are presented in support of continuing research and research planning for the NASA behavioral physiology program. Areas covered include: (1) desynchronosis and performance; (2) effects of alcohol, common colds, drugs, and toxic hazards on performance; (3) effects of stress on rhythm of plasma steroids; (4) data processing of biological rhythms; (5) pharmacology and biological rhythms; (6) mechanisms of biological rhythms; and (7) development of biological rhythms.

Process- and controller-adaptations determine the physiological effects of cold acclimation.

PubMed

Werner, Jürgen

2008-09-01

Experimental results on physiological effects of cold adaptation seem confusing and apparently incompatible with one another. This paper will explain that a substantial part of such a variety of results may be deduced from a common functional concept. A core/shell treatment ("model") of the thermoregulatory system is used with mean body temperature as the controlled variable. Adaptation, as a higher control level, is introduced into the system. Due to persistent stressors, either the (heat transfer) process or the controller properties (parameters) are adjusted (or both). It is convenient to call the one "process adaptation" and the other "controller adaptation". The most commonly demonstrated effect of autonomic cold acclimation is a change in the controller threshold. The analysis shows that this necessarily means a lowering of body temperature because of a lowered metabolic rate. This explains experimental results on both Europeans in the climatic chamber and Australian Aborigines in a natural environment. Exclusive autonomic process adaptation occurs in the form of a better insulation. The analysis explains why the post-adaptive steady-state can only be achieved, if the controller system reduces metabolism and why in spite of this the new state is inevitably characterized by a rise in body temperature. If both process and controller adaptations are simultaneously present, there may be not any change of body temperature at all, e.g., as demonstrated in animal experiments. Whether this kind of adaptation delivers a decrease, an increase or no change of mean body temperature, depends on the proportion of process and controller adaptation.

The Role of Temperature in the Growth and Flowering of Geophytes

PubMed Central

Khodorova, Nadezda V.; Boitel-Conti, Michèle

2013-01-01

Among several naturally occurring environmental factors, temperature is considered to play a predominant role in controlling proper growth and flowering in geophytes. Most of them require a “warm-cold-warm” sequence to complete their annual cycle. The temperature optima for flower meristem induction and the early stages of floral organogenesis vary between nine and 25 °C, followed, in the autumn, by a several-week period of lower temperature (4–9 °C), which enables stem elongation and anthesis. The absence of low temperature treatment leads to slow shoot growth in spring and severe flowering disorders. Numerous studies have shown that the effects of the temperature surrounding the underground organs during the autumn-winter period can lead to important physiological changes in plants, but the mechanism that underlies the relationship between cold treatment and growth is still unclear. In this mini-review, we describe experimental data concerning the temperature requirements for flower initiation and development, shoot elongation, aboveground growth and anthesis in bulbous plants. The physiological processes that occur during autumn-winter periods in bulbs (water status, hormonal balance, respiration, carbohydrate mobilization) and how these changes might provoke disorders in stem elongation and flowering are examined. A model describing the relationship between the cold requirement, auxin and gibberellin interactions and the growth response is proposed. PMID:27137399

Thermal Face Protection Delays Finger Cooling and Improves Thermal Comfort during Cold Air Exposure

DTIC Science & Technology

2011-01-01

code) 2011 Journal Article-Eur Journal of Applied Physiology Thermal face protection delays Fnger cooling and improves thermal comfort during cold air...remains exposed. Facial cooling can decrease finger blood flow, reducing finger temperature (Tf). This study examined whether thermal face protection...limits Wnger cooling and thereby improves thermal comfort and manual dexterity during prolonged cold exposure. Tf was measured in ten volunteers dressed

Preservation of potassium balance is strongly associated with insect cold tolerance in the field: a seasonal study of Drosophila subobscura.

PubMed

MacMillan, Heath A; Schou, Mads F; Kristensen, Torsten N; Overgaard, Johannes

2016-05-01

There is interest in pinpointing genes and physiological mechanisms explaining intra- and interspecific variations in cold tolerance, because thermal tolerance phenotypes strongly impact the distribution and abundance of wild animals. Laboratory studies have highlighted that the capacity to preserve water and ion homeostasis is linked to low temperature survival in insects. It remains unknown, however, whether adaptive seasonal acclimatization in free-ranging insects is governed by the same physiological mechanisms. Here, we test whether cold tolerance in field-caught Drosophila subobscura is high in early spring and lower during summer and whether this transition is associated with seasonal changes in the capacity of flies to preserve water and ion balance during cold stress. Indeed, flies caught during summer were less cold tolerant, and exposure of these flies to sub-zero temperatures caused a loss of haemolymph water and increased the concentration of K(+) in the haemolymph (as in laboratory-reared insects). This pattern of ion and water balance disruption was not observed in more cold-tolerant flies caught in early spring. Thus, we here provide a field verification of hypotheses based on laboratory studies and conclude that the ability to maintain ion homeostasis is important for the ability of free-ranging insects to cope with chilling. © 2016 The Author(s).

Cold-adapted tubulins in the glacier ice worm, Mesenchytraeus solifugus.

PubMed

Tartaglia, Lawrence J; Shain, Daniel H

2008-11-01

Glacier ice worms, Mesenchytraeus solifugus and related species, are the only known annelids that survive obligately in glacier ice and snow. One fundamental component of cold temperature adaptation is the ability to polymerize tubulin, which typically depolymerizes at low physiological temperatures (e.g., <10 degrees C) in most temperate species. In this study, we isolated two alpha-tubulin (Msalpha1, Msalpha2) and two beta-tubulin (Msbeta1, Msbeta2) subunits from an ice worm cDNA library, and compared their predicted amino acid sequences with homologues from other cold-adapted organisms (e.g., Antarctic fish, ciliate) in an effort to identify species-specific amino acid substitutions that contribute to cold temperature-dependent tubulin polymerization. Our comparisons and predicted protein structures suggest that ice worm-specific amino acid substitutions stabilize lateral contact associations, particularly between beta-tubulin protofilaments, but these substitutions occur at different positions in comparison with other cold-adapted tubulins. The ice worm tubulin gene family appears relatively small, comprising one primary alpha- and one primary beta-tubulin monomers, though minor isoforms and pseudogenes were identified. Our analyses suggest that variation occurs in the strategies (i.e., species-specific amino acid substitutions, gene number) by which cold-adapted taxa have evolved the ability to polymerize tubulin at low physiological temperatures.

An Overview of Signaling Regulons During Cold Stress Tolerance in Plants

PubMed Central

Pareek, Amit; Khurana, Ashima; Sharma, Arun K.; Kumar, Rahul

2017-01-01

Plants, being sessile organisms, constantly withstand environmental fluctuations, including low-temperature, also referred as cold stress. Whereas cold poses serious challenges at both physiological and developmental levels to plants growing in tropical or sub-tropical regions, plants from temperate climatic regions can withstand chilling or freezing temperatures. Several cold inducible genes have already been isolated and used in transgenic approach to generate cold tolerant plants. The conventional breeding methods and marker assisted selection have helped in developing plant with improved cold tolerance, however, the development of freezing tolerant plants through cold acclimation remains an unaccomplished task. Therefore, it is essential to have a clear understanding of how low temperature sensing strategies and corresponding signal transduction act during cold acclimation process. Herein, we synthesize the available information on the molecular mechanisms underlying cold sensing and signaling with an aim that the summarized literature will help develop efficient strategies to obtain cold tolerant plants. PMID:29204079

Metabolic and functional characterization of effects of developmental temperature in Drosophila melanogaster.

PubMed

Schou, Mads F; Kristensen, Torsten N; Pedersen, Anders; Karlsson, B Göran; Loeschcke, Volker; Malmendal, Anders

2017-02-01

The ability of ectotherms to respond to changes in their thermal environment through plastic mechanisms is central to their adaptive capability. However, we still lack knowledge on the physiological and functional responses by which ectotherms acclimate to temperatures during development, and in particular, how physiological stress at extreme temperatures may counteract beneficial acclimation responses at benign temperatures. We exposed Drosophila melanogaster to 10 developmental temperatures covering their entire permissible temperature range. We obtained metabolic profiles and reaction norms for several functional traits: egg-to-adult viability, developmental time, and heat and cold tolerance. Females were more heat tolerant than males, whereas no sexual dimorphism was found in cold tolerance. A group of metabolites, mainly free amino acids, had linear reaction norms. Several energy-carrying molecules, as well as some sugars, showed distinct inverted U-shaped norms of reaction across the thermal range, resulting in a positive correlation between metabolite intensities and egg-to-adult viability. At extreme temperatures, low levels of these metabolites were interpreted as a response characteristic of costs of homeostatic perturbations. Our results provide novel insights into a range of metabolites reported to be central for the acclimation response and suggest several new candidate metabolites. Low and high temperatures result in different adaptive physiological responses, but they also have commonalities likely to be a result of the failure to compensate for the physiological stress. We suggest that the regulation of metabolites that are tightly connected to the performance curve is important for the ability of ectotherms to cope with variation in temperature. Copyright © 2017 the American Physiological Society.

Efficacy of fermented green tea on peripheral skin temperature: a randomized and placebo-controlled clinical study.

PubMed

Lee, Eunyoung; Lee, Bum-Jin; Ha, Jaehyoun; Shin, Hyun-Jung; Chung, Jin-Oh

2016-09-01

This study was aimed at assessing the therapeutic efficacy of green tea on peripheral skin for cold hypersensitive subjects, who had the feeling of cold hands and feet at cold temperatures, one of the most common complaints in Asian women. This randomized and placebo-controlled clinical study included 60 female Korean subjects who had the feeling of cold hands and feet at cold temperatures. The subjects were randomly assigned into two groups to receive fermented green tea or a placebo (hot water). The skin temperature of the hands and feet was measured using digital infrared thermography at the baseline and at 15, 30, 45, and 60 min after the oral administration of the tea or placebo. The skin temperature of the hands and feet of the fermented green tea-administered group was significantly higher than that of the placebo-administered group. The temperature difference between the finger and the dorsum of the hand was significantly lower in the fermented green tea-administered group than that in the placebo group. Fermented green tea is helpful for cold hypersensitivity. This is the first clinical study to evaluate the efficacy of fermented green tea on peripheral skin in subjects having the feeling of cold hands and feet at cold temperatures by infrared thermography. However, further studies are necessary to evaluate the long-term effects of the fermented green tea for cold hypersensitivity and to elucidate the underlying physiological mechanism. © 2015 Wiley Periodicals, Inc.

Acid mist and soil Ca and Al alter the mineral nutrition and physiology of red spruce

Treesearch

P.G. Schaberg; D.H. DeHayes; G.J. Hawley; G.R. Strimbeck; J.R. Cumming; P.F. Murakami; C.H. Borer

2000-01-01

We examined the effects and potential interactions of acid mist and soil solution Ca and Al treatments on foliar cation concentrations, membrane-associated Ca (mCa), ion leaching, growth, carbon exchange, and cold tolerance of red spruce (Picea rubens Sarg.) saplings. Soil solution Ca additions increased foliar Ca and Zn concentrations, and increased...

Bibliography on Cold Regions Science and Technology. Volume 51, Part 1.

DTIC Science & Technology

1997-12-01

Loess, Plant ecology, Vegetation patterns, Revegeta- tion, Forestry, Soil conservation, Land reclamation, Regional planning, Statistical analysis...printing. Antikainen, M., Griffith, M., Zhang, J., Hon, W.C., Yang, D.S.C., Pihakaski-Maunsbach, K., Plant physi- ology. Mar. 1996, 110(1), p.845-857...65 refs. Plant physiology, Grasses, Plant tissues, Antifreezes, Acclimatization, Chemical analysis, Chemical prop- erties, Temperature effects

Transcriptomic analysis to uncover genes affecting cold resistance in the Chinese honey bee (Apis cerana cerana).

PubMed

Xu, Kai; Niu, Qingsheng; Zhao, Huiting; Du, Yali; Jiang, Yusuo

2017-01-01

The biological activity and geographical distribution of honey bees is strongly temperature-dependent, due to their ectothermic physiology. In China, the endemic Apis cerana cerana exhibits stronger cold hardiness than Western honey bees, making the former species important pollinators of winter-flowering plants. Although studies have examined behavioral and physiological mechanisms underlying cold resistance in bees, data are scarce regarding the exact molecular mechanisms. Here, we investigated gene expression in A. c. cerana under two temperature treatments, using transcriptomic analysis to identify differentially expressed genes (DEGs) and relevant biological processes, respectively. Across the temperature treatments, 501 DEGs were identified. A gene ontology analysis showed that DEGs were enriched in pathways related to sugar and amino acid biosynthesis and metabolism, as well as calcium ion channel activity. Additionally, heat shock proteins, zinc finger proteins, and serine/threonine-protein kinases were differentially expressed between the two treatments. The results of this study provide a general digital expression profile of thermoregulation genes responding to cold hardiness in A. c. cerana. Our data should prove valuable for future research on cold tolerance mechanisms in insects, and may be beneficial in breeding efforts to improve bee hardiness.

Insect capa neuropeptides impact desiccation and cold tolerance

PubMed Central

Terhzaz, Selim; Teets, Nicholas M.; Cabrero, Pablo; Henderson, Louise; Ritchie, Michael G.; Nachman, Ronald J.; Dow, Julian A. T.; Denlinger, David L.; Davies, Shireen-A.

2015-01-01

The success of insects is linked to their impressive tolerance to environmental stress, but little is known about how such responses are mediated by the neuroendocrine system. Here we show that the capability (capa) neuropeptide gene is a desiccation- and cold stress-responsive gene in diverse dipteran species. Using targeted in vivo gene silencing, physiological manipulations, stress-tolerance assays, and rationally designed neuropeptide analogs, we demonstrate that the Drosophila melanogaster capa neuropeptide gene and its encoded peptides alter desiccation and cold tolerance. Knockdown of the capa gene increases desiccation tolerance but lengthens chill coma recovery time, and injection of capa peptide analogs can reverse both phenotypes. Immunohistochemical staining suggests that capa accumulates in the capa-expressing Va neurons during desiccation and nonlethal cold stress but is not released until recovery from each stress. Our results also suggest that regulation of cellular ion and water homeostasis mediated by capa peptide signaling in the insect Malpighian (renal) tubules is a key physiological mechanism during recovery from desiccation and cold stress. This work augments our understanding of how stress tolerance is mediated by neuroendocrine signaling and illustrates the use of rationally designed peptide analogs as agents for disrupting protective stress tolerance. PMID:25730885

Metabolic and respiratory status of cold-stunned Kemp's ridley sea turtles (Lepidochelys kempii).

PubMed

Innis, Charles J; Tlusty, Michael; Merigo, Constance; Weber, E Scott

2007-08-01

"Cold-stunning" of sea turtles has been reported as a naturally occurring stressor for many years; however, the physiologic status of cold-stunned turtles has only been partially described. This study investigated initial and convalescent venous blood gas, acid-base, and critical plasma biochemical data for 26 naturally cold-stunned Kemp's ridley sea turtles (Lepidochelys kempii) from Cape Cod, MA, USA. Samples were analyzed for pH, pCO(2), pO(2), bicarbonate, plasma osmolality, sodium, potassium, chloride, ionized calcium, ionized magnesium, glucose, lactate, and blood urea nitrogen using a clinical point-of-care analyzer. Data were corrected for the patient's body temperature using both species-specific and more general correction methods. In general, venous blood gas, acid-base, and plasma biochemical data obtained for surviving cold-stunned Kemp's ridley sea turtles were consistent with previously documented data for sea turtles exposed to a wide range of temperatures and physiologic stressors. Data indicated that turtles were initially affected by metabolic and respiratory acidosis. Initial pH-corrected ionized calcium concentrations were lower than convalescent concentrations, and initial pH-corrected ionized magnesium concentrations were higher than convalescent concentrations.

Mild dehydration modifies the cerebrovascular response to the cold pressor test.

PubMed

Perry, Blake G; Bear, Tracey L K; Lucas, Samuel J E; Mündel, Toby

2016-01-01

The cold pressor test (CPT) is widely used in clinical practice and physiological research. It is characterized by a robust autonomic response, with associated increases in heart rate (HR), mean arterial pressure (MAP) and mean middle cerebral artery blood flow velocity (MCAv(mean)). Hydration status is not commonly reported when conducting this test, yet blood viscosity alone can modulate MCAv(mean), potentially modifying the MCAv(mean) response to the CPT. We investigated the effect of mild dehydration on the physiological response to the CPT in 10 healthy men (mean ± SD: age 28 ± 5 years; body mass 83 ± 5 kg). All participants completed two CPTs, cold water (0°C) immersion of both feet for 90 s, with the order of the euhydration and dehydration trials counterbalanced. Beat-to-beat MCAv, MAP, HR and breath-by-breath partial pressure of end-tidal CO2 (P(ET,CO2)) were measured continuously. Participants' pain perception was measured 1 min into the CPT using a visual analog scale (no pain = 0; maximal pain = 10). Dehydration significantly elevated plasma osmolality and urine specific gravity and reduced body mass (all P < 0.01). The MAP and HR responses were not different between treatments (both P > 0.05). After 90 s of immersion, the change in MCAv(mean) from baseline was less in the dehydration compared with the euhydration trial (change 0 ± 5 versus 7 ± 7 cm s(-1), P = 0.01), as was P(ET,CO2) (change -3 ± 2 versus 0 ± 3 mmHg, P = 0.02). Dehydration was associated with greater relative pain sensation during the CPT (7.0 ± 1.3 vs 5.8 ± 1.8, P = 0.02). Our results demonstrate that mild dehydration can modify the cerebrovascular response to the CPT, with dehydration increasing perceived pain, lowering P ET ,CO2 and, ultimately, blunting the MCAv(mean) response. © 2015 The Authors. Experimental Physiology © 2015 The Physiological Society.

Transcriptomic analysis of fruit stored under cold conditions using controlled atmosphere in Prunus persica cv. "Red Pearl".

PubMed

Sanhueza, Dayan; Vizoso, Paula; Balic, Iván; Campos-Vargas, Reinaldo; Meneses, Claudio

2015-01-01

Cold storage (CS) can induce a physiological disorder known as chilling injury (CI) in nectarine fruits. The main symptom is mealiness that is perceived as non-juicy fruit by consumers. Postharvest treatments such as controlled atmosphere (CA; a high CO2 concentration and low O2) have been used under cold conditions to avoid this disorder. With the objective of exploring the mechanisms involved in the CA effect on mealiness prevention, we analyzed transcriptomic changes under six conditions of "Red Pearl" nectarines by RNA-Seq. Our analysis included just harvested nectarines, juicy non-stored fruits, fruits affected for CI after CS and fruits stored in a combination of CA plus CS without CI phenotype. Nectarines stored in cold conditions combined with CA treatment resulted in less mealiness; we obtained 21.6% of juice content compared with just CS fruits (7.7%; mealy flesh). RNA-Seq data analyses were carried out to study the gene expression for different conditions assayed. During ripening, we detected that nectarines exposed to CA treatment expressed a similar number of genes compared with fruits that were not exposed to cold conditions. Firm fruits have more differentially expressed genes than soft fruits, which suggest that most important changes occur during CS. On the other hand, gene ontology analysis revealed enrichment mainly in metabolic and cellular processes. Differentially expressed genes analysis showed that low O2 concentrations combined with cold conditions slows the metabolic processes more than just the cold storage, resulting mainly in the suppression of primary metabolism and cold stress response. This is a significant step toward unraveling the molecular mechanism that explains the effectiveness of CA as a tool to prevent CI development on fruits.

Transcriptomic analysis of fruit stored under cold conditions using controlled atmosphere in Prunus persica cv. “Red Pearl”

PubMed Central

Sanhueza, Dayan; Vizoso, Paula; Balic, Iván; Campos-Vargas, Reinaldo; Meneses, Claudio

2015-01-01

Cold storage (CS) can induce a physiological disorder known as chilling injury (CI) in nectarine fruits. The main symptom is mealiness that is perceived as non-juicy fruit by consumers. Postharvest treatments such as controlled atmosphere (CA; a high CO2 concentration and low O2) have been used under cold conditions to avoid this disorder. With the objective of exploring the mechanisms involved in the CA effect on mealiness prevention, we analyzed transcriptomic changes under six conditions of “Red Pearl” nectarines by RNA-Seq. Our analysis included just harvested nectarines, juicy non-stored fruits, fruits affected for CI after CS and fruits stored in a combination of CA plus CS without CI phenotype. Nectarines stored in cold conditions combined with CA treatment resulted in less mealiness; we obtained 21.6% of juice content compared with just CS fruits (7.7%; mealy flesh). RNA-Seq data analyses were carried out to study the gene expression for different conditions assayed. During ripening, we detected that nectarines exposed to CA treatment expressed a similar number of genes compared with fruits that were not exposed to cold conditions. Firm fruits have more differentially expressed genes than soft fruits, which suggest that most important changes occur during CS. On the other hand, gene ontology analysis revealed enrichment mainly in metabolic and cellular processes. Differentially expressed genes analysis showed that low O2 concentrations combined with cold conditions slows the metabolic processes more than just the cold storage, resulting mainly in the suppression of primary metabolism and cold stress response. This is a significant step toward unraveling the molecular mechanism that explains the effectiveness of CA as a tool to prevent CI development on fruits. PMID:26483806

Cold Tolerance of Pityophthorus juglandis (Coleoptera: Scolytidae) From Northern California

Treesearch

Andrea R. Hefty; Steven J. Seybold; Brian H. Aukema; Robert C. Venette

2017-01-01

Winter survivorship of insects is determined by a combination of physiological, behavioral, and microhabitat characteristics. We characterized the cold tolerance of the walnut twig beetle, Pityophthorus juglandis Blackman, a domestic alien invasive bark beetle that vectors a phytopathogenic fungus. The beetle and fungus cause thousand cankers...

Calcium addition at the Hubbard Brook Experimental Forest increases the capacity for stress tolerance and carbon capture in red spruce (Picea rubens) trees during the cold season

Treesearch

Paul G. Schaberg; Rakesh Minocha; Stephanie Long; Joshua M. Halman; Gary J. Hawley; Christopher Eagar

2011-01-01

Red spruce (Picea rubens Sarg.) trees are uniquely vulnerable to foliar freezing injury during the cold season (fall and winter), but are also capable of photosynthetic activity if temperatures moderate. To evaluate the influence of calcium (Ca) addition on the physiology of red spruce during the cold season, we measured concentrations of foliar...

Seed Germination Ecology of the Cold Desert Annual Isatis violascens (Brassicaceae): Two Levels of Physiological Dormancy and Role of the Pericarp

PubMed Central

Tan, Dun Y.; Baskin, Carol C.; Baskin, Jerry M.

2015-01-01

The occurrence of various species of Brassicaceae with indehiscent fruits in the cold deserts of NW China suggests that there are adaptive advantages of this trait. We hypothesized that the pericarp of the single-seeded silicles of Isatis violascens restricts embryo expansion and thus prevents germination for 1 or more years. Thus, our aim was to investigate the role of the pericarp in seed dormancy and germination of this species. The effects of afterripening, treatment with gibberellic acid (GA3) and cold stratification on seed dormancy-break were tested using intact silicles and isolated seeds, and germination phenology was monitored in an experimental garden. The pericarp has a role in mechanically inhibiting germination of fresh seeds and promotes germination of nondormant seeds, but it does not facilitate formation of a persistent seed bank. Seeds in silicles in watered soil began to germinate earlier in autumn and germinated to higher percentages than isolated seeds. Sixty-two percent of seeds in the buried silicles germinated by the end of the first spring, and only 3% remained nongerminated and viable. Twenty to twenty-five percent of the seeds have nondeep physiological dormancy (PD) and 75–80% intermediate PD. Seeds with nondeep PD afterripen in summer and germinate inside the silicles in autumn if the soil is moist. Afterripening during summer significantly decreased the amount of cold stratification required to break intermediate PD. The presence of both nondeep and intermediate PD in the seed cohort may be a bet-hedging strategy. PMID:26513241

National Athletic Trainers' Association position statement: environmental cold injuries.

PubMed

Cappaert, Thomas A; Stone, Jennifer A; Castellani, John W; Krause, Bentley Andrew; Smith, Daniel; Stephens, Bradford A

2008-01-01

To present recommendations for the prevention, recognition, and treatment of environmental cold injuries. Individuals engaged in sport-related or work-related physical activity in cold, wet, or windy conditions are at risk for environmental cold injuries. An understanding of the physiology and pathophysiology, risk management, recognition, and immediate care of environmental cold injuries is an essential skill for certified athletic trainers and other health care providers working with individuals at risk. These recommendations are intended to provide certified athletic trainers and others participating in athletic health care with the specific knowledge and problem-solving skills needed to address environmental cold injuries. Each recommendation has been graded (A, B, or C) according to the Strength of Recommendation Taxonomy criterion scale.

National Athletic Trainers' Association Position Statement: Environmental Cold Injuries

PubMed Central

Cappaert, Thomas A; Stone, Jennifer A; Castellani, John W; Krause, Bentley Andrew; Smith, Daniel; Stephens, Bradford A

2008-01-01

Objective: To present recommendations for the prevention, recognition, and treatment of environmental cold injuries. Background: Individuals engaged in sport-related or work-related physical activity in cold, wet, or windy conditions are at risk for environmental cold injuries. An understanding of the physiology and pathophysiology, risk management, recognition, and immediate care of environmental cold injuries is an essential skill for certified athletic trainers and other health care providers working with individuals at risk. Recommendations: These recommendations are intended to provide certified athletic trainers and others participating in athletic health care with the specific knowledge and problem-solving skills needed to address environmental cold injuries. Each recommendation has been graded (A, B, or C) according to the Strength of Recommendation Taxonomy criterion scale. PMID:19030143

Molecular mechanisms underlying the physiological responses of the cold-water coral Desmophyllum dianthus to ocean acidification

NASA Astrophysics Data System (ADS)

Carreiro-Silva, M.; Cerqueira, T.; Godinho, A.; Caetano, M.; Santos, R. S.; Bettencourt, R.

2014-06-01

Cold-water corals (CWCs) are thought to be particularly vulnerable to ocean acidification (OA) due to increased atmospheric pCO2, because they inhabit deep and cold waters where the aragonite saturation state is naturally low. Several recent studies have evaluated the impact of OA on organism-level physiological processes such as calcification and respiration. However, no studies to date have looked at the impact at the molecular level of gene expression. Here, we report results of a long-term, 8-month experiment to compare the physiological responses of the CWC Desmophyllum dianthus to OA at both the organismal and gene expression levels under two pCO2/pH treatments: ambient pCO2 (460 μatm, pHT = 8.01) and elevated pCO2 (997 μatm, pHT = 7.70). At the organismal level, no significant differences were detected in the calcification and respiration rates of D. dianthus. Conversely, significant differences were recorded in gene expression profiles, which showed an up-regulation of genes involved in cellular stress (HSP70) and immune defence (mannose-binding c-type lectin). Expression of alpha-carbonic anhydrase, a key enzyme involved in the synthesis of coral skeleton, was also significantly up-regulated in corals under elevated pCO2, indicating that D. dianthus was under physiological reconditioning to calcify under these conditions. Thus, gene expression profiles revealed physiological impacts that were not evident at the organismal level. Consequently, understanding the molecular mechanisms behind the physiological processes involved in a coral's response to elevated pCO2 is critical to assess the ability of CWCs to acclimate or adapt to future OA conditions.

Cardiovascular and autonomic responses to physiological stressors before and after six hours of water immersion.

PubMed

Florian, John P; Simmons, Erin E; Chon, Ki H; Faes, Luca; Shykoff, Barbara E

2013-11-01

The physiological responses to water immersion (WI) are known; however, the responses to stress following WI are poorly characterized. Ten healthy men were exposed to three physiological stressors before and after a 6-h resting WI (32-33°C): 1) a 2-min cold pressor test, 2) a static handgrip test to fatigue at 40% of maximum strength followed by postexercise muscle ischemia in the exercising forearm, and 3) a 15-min 70° head-up-tilt (HUT) test. Heart rate (HR), systolic and diastolic blood pressure (SBP and DBP), cardiac output (Q), limb blood flow (BF), stroke volume (SV), systemic and calf or forearm vascular resistance (SVR and CVR or FVR), baroreflex sensitivity (BRS), and HR variability (HRV) frequency-domain variables [low-frequency (LF), high-frequency (HF), and normalized (n)] were measured. Cold pressor test showed lower HR, SBP, SV, Q, calf BF, LFnHRV, and LF/HFHRV and higher CVR and HFnHRV after than before WI (P < 0.05). Handgrip test showed no effect of WI on maximum strength and endurance and lower HR, SBP, SV, Q, and calf BF and higher SVR and CVR after than before WI (P < 0.05). During postexercise muscle ischemia, HFnHRV increased from baseline after WI only, and LFnHRV was lower after than before WI (P < 0.05). HUT test showed lower SBP, DBP, SV, forearm BF, and BRS and higher HR, FVR, LF/HFHRV, and LFnHRV after than before WI (P < 0.05). The changes suggest differential activation/depression during cold pressor and handgrip (reduced sympathetic/elevated parasympathetic) and HUT (elevated sympathetic/reduced parasympathetic) following 6 h of WI.

Delayed response to cold stress is characterized by successive metabolic shifts culminating in apple fruit peel necrosis

USDA-ARS?s Scientific Manuscript database

Superficial scald is a physiological disorder of apple fruit characterized by sunken, necrotic lesions appearing after prolonged cold storage, although initial injury occurs much earlier in the storage period. To determine the degree to which the transition to cell death is an active process and sp...

Morpho-physiological characterization of cold-and pre-flowering drought tolerance in grain Sorghum (Sorghum bicolor L. Moench) inbreds

USDA-ARS?s Scientific Manuscript database

Aim: The relationships between early-season cold temperature germination and preflowering drought stress in eight grain sorghum inbreds were assessed using morphophysiological traits. Study Design: Field was laid out in a randomized complete block design. Place and Duration: The experiment was condu...

Influence of sky view factor on outdoor thermal environment and physiological equivalent temperature

NASA Astrophysics Data System (ADS)

He, Xiaodong; Miao, Shiguang; Shen, Shuanghe; Li, Ju; Zhang, Benzhi; Zhang, Ziyue; Chen, Xiujie

2015-03-01

Sky view factor (SVF), which is an indicator of urban canyon geometry, affects the surface energy balance, local air circulation, and outdoor thermal comfort. This study focused on a continuous and long-term meteorological observation system to investigate the effects of SVF on outdoor thermal conditions and physiological equivalent temperature (PET) in the central business district (CBD) of Beijing (which is located within Chaoyang District), specifically addressed current knowledge gaps for SVF-PET relationships in cities with typical continental/microthermal climates. An urban sub-domain scale model and the RayMan model were used to diagnose wind fields and to calculate SVF and long-term PET, respectively. Analytical results show that the extent of shading contributes to variations in thermal perception distribution. Highly shaded areas (SVF <0.3) typically exhibit less frequent hot conditions during summer, while enduring longer periods of cold discomfort in winter than moderately shaded areas (0.3< SVF <0.5) and slightly shaded areas (SVF >0.5), and vice versa. Because Beijing has a monsoon-influenced humid continental climate with hot summers and long, cold, windy, and dry winters, a design project that ideally provides moderate shading should be planned to balance hot discomfort in summer and cold discomfort in winter, which effectively prolongs the comfort periods in outdoor spaces throughout the entire year. This research indicate that climate zone characteristics, urban environmental conditions, and thermal comfort requirements of residents must be accounted for in local-scale scientific planning and design, i.e., for urban canyon streets and residential estates.

A critical test of Drosophila anaesthetics: Isoflurane and sevoflurane are benign alternatives to cold and CO2.

PubMed

MacMillan, Heath A; Nørgård, Mikkel; MacLean, Heidi J; Overgaard, Johannes; Williams, Catherine J A

2017-08-01

Anaesthesia is often a necessary step when studying insects like the model organism Drosophila melanogaster. Most studies of Drosophila and other insects that require anaesthesia use either cold exposure or carbon dioxide exposure to induce a narcotic state. These anaesthetic methods are known to disrupt physiology and behavior with increasing exposure, and thus ample recovery time is required prior to experimentation. Here, we examine whether two halogenated ethers commonly used in vertebrate anaesthesia, isoflurane and sevoflurane, may serve as alternative means of insect anaesthesia. Using D. melanogaster, we generated dose-response curves to identify exposure times for each anaesthetic (cold, CO 2 , isoflurane and sevoflurane) that allow for five-minutes of experimental manipulation of the animals after the anaesthetic was removed (i.e. 5min recovery doses). We then compared the effects of this practical dose on high temperature, low temperature, starvation, and desiccation tolerance, as well as locomotor activity and fecundity of female flies following recovery from anaesthesia. Cold, CO 2 and isoflurane each had significant or near significant effects on the traits measured, but the specific effects of each anaesthetic differed, and effects on stress tolerance generally did not persist if the flies were given 48h to recover from anaesthesia. Sevoflurane had no measureable effect on any of the traits examined. Care must be taken when choosing an anaesthetic in Drosophila research, as the impacts of specific anaesthetics on stress tolerance, behavior and reproduction can widely differ. Sevoflurane may be a practical alternative to cold and CO 2 anaesthesia in insects - particularly if flies are to be used for experiments shortly after anesthesia. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hemodynamic and thermoregulatory responses to lower body water immersion.

PubMed

Muller, Matthew D; Kim, Cihul-Ho; Seo, Yongsuk; Ryan, Edward J; Glickman, Ellen L

2012-10-01

Lower body water immersion (LBWI) is experienced in the marine industry but the physiological responses to LBWI are unclear. The purpose of the current experiment was to test the effects of water temperature and immersion duration on rectal temperature, heart rate, stroke volume, blood pressure, metabolic rate, and thermal sensation in healthy subjects. Nine young men underwent two 60-min trials of seated LBWI to the iliac crest in a counterbalanced fashion. On one occasion, the water was 35 degrees C (LBWI-Neutral) and on the other it was 13 degrees C (LBWI-Cold); the upper body remained thermoneutral and dry throughout. As expected, exposure to cold water reduced mean skin temperature and individuals reported cold thermal sensation. Mean arterial pressure was significantly higher at 60 min of LBWI-Cold (86 +/- 7 mmHg) compared to LBWI-Neutral (76 +/- 5 mmHg) while heart rate tended to be lower. The change in rectal temperature from baseline to 30 min of LBWI-Cold (delta = -0.01 +/- 0.21degrees C) was significantly smaller than the change in T(re) from 30 to 60 min of LBWI-Cold (delta = -0.46 +/- 0.16 degrees C). Despite this accelerated drop in core temperature during minutes 30-60, metabolic rate did not increase significantly. LBWI-Cold reduces core temperature and increases arterial blood pressure via an increase in total peripheral resistance. This experimental model may help scientists better understand the body during cold stress. Further, people who are occupationally exposed to cold water (when the torso, hands, and arms remain thermoneutral) may be at increased risk for hypothermia.

The Pineal and Photoperiodism in Artic Species,

DTIC Science & Technology

1977-01-01

University of Iowa, Iowa City, Iowa *1 A chapter in the book: The Pineal Gland and Reproduction / ::. . / .. ,, " /-. ., . / >( JUN19 1981 A and sale; . td...Three Kinds of Bird Pineal Glands Arctic Mammals and Photoperiod Outline of Arctic Reproductive Physiology Arctic Pineal Physiology: Size Arctic... pineal physiology. Because this gland is not only associated with photoperiodic responses with some species, but also with resistance to cold (14; 21

Cold adaptation, aging, and Korean women divers haenyeo.

PubMed

Lee, Joo-Young; Park, Joonhee; Kim, Siyeon

2017-08-08

We have been studying the thermoregulatory responses of Korean breath-hold women divers, called haenyeo, in terms of aging and cold adaptation. During the 1960s to the 1980s, haenyeos received attention from environmental physiologists due to their unique ability to endure cold water while wearing only a thin cotton bathing suit. However, their overall cold-adaptive traits have disappeared since they began to wear wetsuits and research has waned since the 1980s. For social and economic reasons, the number of haenyeos rapidly decreased to 4005 in 2015 from 14,143 in 1970 and the average age of haenyeos is about 75 years old at present. For the past several years, we revisited and explored older haenyeos in terms of environmental physiology, beginning with questionnaire and field studies and later advancing to thermal tolerance tests in conjunction with cutaneous thermal threshold tests in a climate chamber. As control group counterparts, older non-diving females and young non-diving females were compared with older haenyeos in the controlled experiments. Our findings were that older haenyeos still retain local cold tolerance on the extremities despite their aging. Finger cold tests supported more superior local cold tolerance for older haenyeos than for older non-diving females. However, thermal perception in cold reflected aging effects rather than local cold acclimatization. An interesting finding was the possibility of positive cross-adaptation which might be supported by greater heat tolerance and cutaneous warm perception thresholds of older haenyeos who adapted to cold water. It was known that cold-adaptive traits of haenyeos disappeared, but we confirmed that cold-adaptive traits are still retained on the face and hands which could be interpreted by a mode switch to local adaptation from the overall adaptation to cold. Further studies on cross-adaptation between chronic cold stress and heat tolerance are needed.

The effect of temperature and thermal acclimation on the sustainable performance of swimming scup.

PubMed

Rome, Lawrence C

2007-11-29

There is a significant reduction in overall maximum power output of muscle at low temperatures due to reduced steady-state (i.e. maximum activation) power-generating capabilities of muscle. However, during cyclical locomotion, a further reduction in power is due to the interplay between non-steady-state contractile properties of muscle (i.e. rates of activation and relaxation) and the stimulation and the length-change pattern muscle undergoes in vivo. In particular, even though the relaxation rate of scup red muscle is slowed greatly at cold temperatures (10 degrees C), warm-acclimated scup swim with the same stimulus duty cycles at cold as they do at warm temperature, not affording slow-relaxing muscle any additional time to relax. Hence, at 10 degrees C, red muscle generates extremely low or negative work in most parts of the body, at all but the slowest swimming speeds. Do scup shorten their stimulation duration and increase muscle relaxation rate during cold acclimation? At 10 degrees C, electromyography (EMG) duty cycles were 18% shorter in cold-acclimated scup than in warm-acclimated scup. But contrary to the expectations, the red muscle did not have a faster relaxation rate, rather, cold-acclimated muscle had an approximately 50% faster activation rate. By driving cold- and warm-acclimated muscle through cold- and warm-acclimated conditions, we found a very large increase in red muscle power during swimming at 10 degrees C. As expected, reducing stimulation duration markedly increased power output. However, the increased rate of activation alone produced an even greater effect. Hence, to fully understand thermal acclimation, it is necessary to examine the whole system under realistic physiological conditions.

Diving Response in Rats: Role of the Subthalamic Vasodilator Area

PubMed Central

Golanov, Eugene V.; Shiflett, James M.; Britz, Gavin W.

2016-01-01

Diving response (DR) is a powerful integrative response targeted toward survival of the hypoxic/anoxic conditions. Being present in all animals and humans, it allows to survive adverse conditions like diving. Earlier, we discovered that forehead stimulation affords neuroprotective effect, decreasing infarction volume triggered by permanent occlusion of the middle cerebral artery in rats. We hypothesized that cold stimulation of the forehead induces DR in rats, which, in turn, exerts neuroprotection. We compared autonomic [AP, heart rate (HR), cerebral blood flow (CBF)] and EEG responses to the known DR-triggering stimulus, ammonia stimulation of the nasal mucosa, cold stimulation of the forehead, and cold stimulation of the glabrous skin of the tail base in anesthetized rats. Responses in AP, HR, CBF, and EEG to cold stimulation of the forehead and ammonia vapors instillation into the nasal cavity were comparable and differed significantly from responses to the cold stimulation of the tail base. Excitotoxic lesion of the subthalamic vasodilator area (SVA), which is known to participate in CBF regulation and to afford neuroprotection upon excitation, failed to affect autonomic components of the DR evoked by forehead cold stimulation or nasal mucosa ammonia stimulation. We conclude that cold stimulation of the forehead triggers physiological response comparable to the response evoked by ammonia vapor instillation into nasal cavity, which is considered as stimulus triggering protective DR. These observations may explain the neuroprotective effect of the forehead stimulation. Data demonstrate that SVA does not directly participate in the autonomic adjustments accompanying DR; however, it is involved in diving-evoked modulation of EEG. We suggest that forehead stimulation can be employed as a stimulus capable of triggering oxygen-conserving DR and can be used for neuroprotective therapy. PMID:27708614

Divergent Regulation of CBF Regulon on Cold Tolerance and Plant Phenotype in Cassava Overexpressing Arabidopsis CBF3 Gene.

PubMed

An, Dong; Ma, Qiuxiang; Yan, Wei; Zhou, Wenzhi; Liu, Guanghua; Zhang, Peng

2016-01-01

Cassava is a tropical origin plant that is sensitive to chilling stress. In order to understand the CBF cold response pathway, a well-recognized regulatory mechanism in temperate plants, in cassava, overexpression of an Arabidopsis CBF3 gene is studied. This gene renders cassava increasingly tolerant to cold and drought stresses but is associated with retarded plant growth, leaf curling, reduced storage root yield, and reduced anthocyanin accumulation in a transcript abundance-dependent manner. Physiological analysis revealed that the transgenic cassava increased proline accumulation, reduced malondialdehyde production, and electrolyte leakage under cold stress. These transgenic lines also showed high relative water content when faced with drought. The expression of partial CBF-targeted genes in response to cold displayed temporal and spatial variations in the wild-type and transgenic plants: highly inducible in leaves and less altered in apical buds. In addition, anthocyanin accumulation was inhibited by downregulating the expression of genes involved in its biosynthesis and by interplaying between the CBF3 and the endogenous transcription factors. Thus, the heterologous CBF3 modulates the expression of stress-related genes and carries out a series of physiological adjustments under stressful conditions, showing a varied regulation pattern of CBF regulon from that of cassava CBFs.

Early sign of microangiopathy in systemic sclerosis: The significance of cold stress test in dynamic laser Doppler flowmetry.

PubMed

Yu, Sebastian; Hu, Stephen Chu-Sung; Yu, Hsin-Su; Chin, Yi-Ying; Cheng, Yang-Chun; Lee, Chih-Hung

2018-06-05

Skin physiology measurement is receiving more attention for detecting vasculopathy in systemic sclerosis (SSc). Laser Doppler flowmetry (LDF) is a widely used physiological measurement to assess cutaneous microcirculation. However, findings of LDF may be normal during early stage of microangiopathy in SSc. We hypothesized that cold stress test combined with LDF could detect early-stage microangiopathy in patients with SSc. A 67-year-old male came with multiple ulcerations on his fingers for one year. After excluding diseases such as diabetes mellitus-related peripheral arterial occlusive disease and smoking-related Buerger's disease, the diagnosis of SSc was made according to the 2013 ACR/EULAR criteria. We performed LDF and angiography for a patient with SSc and compared the results. Although occlusions of right ulnar and digital arteries were obvious in angiography, the baseline skin temperature and perfusion unit on right fingers remained within normal limits. While the microcirculatory abnormalities measured by LDF alone are subtle, LDF combined with cold stress test detected a significant slow recovery of skin blood flow 40 minutes after cold immersion. In conclusion, there may be discordance between macrovasculopathy and baseline microcirculatory blood flow in SSc. In such a case, cold immersion test is essential to measure the dynamic change and slow recovery of blood flow.

Whole- and partial-body cryostimulation/cryotherapy: Current technologies and practical applications.

PubMed

Bouzigon, Romain; Grappe, Frederic; Ravier, Gilles; Dugue, Benoit

2016-10-01

Cold therapy is commonly used as a method to relieve pain and inflammation. This review focuses primarily on two methods of cold therapy that have received recent attention: whole-body cryotherapy and partial-body cryotherapy. These methods are used to induce physiological and psychological benefits in humans in the context of medicine, health and sports. The subjects experiencing cryotherapy are dressed in minimal clothing and are exposed to very cold air (at -110°C or less) for 1-4min. Despite the increasing scientific interest in these methods, there is a lack of information about the technologies used. Moreover, there is no existing reference concerning exposure protocols and the relationship between temperature, duration, number of repetitions and the treatments' desired effects. The aim of this review is to compare whole- and partial-body cryotherapy effects (especially on skin temperature) and to classify the protocols for exposure according to the desired effects. This review emphasises 1) the lack of information concerning the actual temperatures inside the cabin or chamber during exposure and 2) the heterogeneity among the exposure protocols that have been reported in the scientific literature. This review will be valuable and relevant to health professionals endeavouring to optimize the cold treatments offered to patients and producers of cryotherapy apparatus striving to create more efficient devices that meet market requirements. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparing Enchytraeus albidus populations from contrasting climatic environments suggest a link between cold tolerance and metabolic activity.

PubMed

Žagar, Anamarija; Holmstrup, Martin; Simčič, Tatjana; Debeljak, Barabara; Slotsbo, Stine

2018-06-06

Basal metabolic activity and freezing of body fluids create reactive oxygen species (ROS) in freeze-tolerant organisms. These sources of ROS can have an additive negative effect via oxidative stress. In cells, antioxidant systems are responsible for removing ROS in order to avoid damage due to oxidative stress. Relatively little is known about the importance of metabolic rate for the survival of freezing, despite a good understanding of several cold tolerance related physiological mechanisms. We hypothesized that low basal metabolism would be selected for in freeze-tolerant organisms where winter survival is important for fitness for two reasons. First, avoidance of the additive effect of ROS production from metabolism and freezing, and second, as an energy-saving mechanism under extended periods of freezing where the animal is metabolically active, but unable to feed. We used the terrestrial oligochaete, Enchytraeus albidus, which is widely distributed from Spain to the high Arctic and compared eight populations originating across a broad geographical and climatic gradient after they had been cold acclimated at 5 °C in a common garden experiment. Cold tolerance (lower lethal temperature: LT50) and the potential metabolic activity (PMA, an estimator of the maximal enzymatic potential of the mitochondrial respiration chain) of eight populations were positively correlated amongst each other and correlated negatively with latitude and positively with average yearly temperature and the average temperature of the coldest month. These results indicate that low PMA in cold tolerant populations is important for survival in extremely cold environments. Copyright © 2018 Elsevier Inc. All rights reserved.

Musical Agency during Physical Exercise Decreases Pain.

PubMed

Fritz, Thomas H; Bowling, Daniel L; Contier, Oliver; Grant, Joshua; Schneider, Lydia; Lederer, Annette; Höer, Felicia; Busch, Eric; Villringer, Arno

2017-01-01

Objectives: When physical exercise is systematically coupled to music production, exercisers experience improvements in mood, reductions in perceived effort, and enhanced muscular efficiency. The physiology underlying these positive effects remains unknown. Here we approached the investigation of how such musical agency may stimulate the release of endogenous opioids indirectly with a pain threshold paradigm. Design: In a cross-over design we tested the opioid-hypothesis with an indirect measure, comparing the pain tolerance of 22 participants following exercise with or without musical agency. Method: Physical exercise was coupled to music by integrating weight-training machines with sensors that control music-synthesis in real time. Pain tolerance was measured as withdrawal time in a cold pressor test. Results: On average, participants tolerated cold pain for ~5 s longer following exercise sessions with musical agency. Musical agency explained 25% of the variance in cold pressor test withdrawal times after factoring out individual differences in general pain sensitivity. Conclusions: This result demonstrates a substantial pain reducing effect of musical agency in combination with physical exercise, probably due to stimulation of endogenous opioid mechanisms. This has implications for exercise endurance, both in sports and a multitude of rehabilitative therapies in which physical exercise is effective but painful.

Musical Agency during Physical Exercise Decreases Pain

PubMed Central

Fritz, Thomas H.; Bowling, Daniel L.; Contier, Oliver; Grant, Joshua; Schneider, Lydia; Lederer, Annette; Höer, Felicia; Busch, Eric; Villringer, Arno

2018-01-01

Objectives: When physical exercise is systematically coupled to music production, exercisers experience improvements in mood, reductions in perceived effort, and enhanced muscular efficiency. The physiology underlying these positive effects remains unknown. Here we approached the investigation of how such musical agency may stimulate the release of endogenous opioids indirectly with a pain threshold paradigm. Design: In a cross-over design we tested the opioid-hypothesis with an indirect measure, comparing the pain tolerance of 22 participants following exercise with or without musical agency. Method: Physical exercise was coupled to music by integrating weight-training machines with sensors that control music-synthesis in real time. Pain tolerance was measured as withdrawal time in a cold pressor test. Results: On average, participants tolerated cold pain for ~5 s longer following exercise sessions with musical agency. Musical agency explained 25% of the variance in cold pressor test withdrawal times after factoring out individual differences in general pain sensitivity. Conclusions: This result demonstrates a substantial pain reducing effect of musical agency in combination with physical exercise, probably due to stimulation of endogenous opioid mechanisms. This has implications for exercise endurance, both in sports and a multitude of rehabilitative therapies in which physical exercise is effective but painful. PMID:29387030

Germination of dimorphic seeds of Suaeda aralocaspica in response to light and salinity conditions during and after cold stratification

PubMed Central

Wang, Hong-Ling; Tian, Chang-Yan

2017-01-01

Cold stratification is a requirement for seed dormancy breaking in many species, and thus it is one of the important factors for the regulation of timing of germination. However, few studies have examined the influence of various environmental conditions during cold stratification on subsequent germination, and no study has compared such effects on the performance of dormant versus non-dormant seeds. Seeds of halophytes in the cold desert might experience different light and salinity conditions during and after cold stratification. As such, dimorphic seeds (non-dormant brown seeds and black seeds with non-deep physiological dormancy) of Suaeda aralocaspica were cold stratified under different light (12 h light–12 h darkness photoperiod or continuous darkness) or salinity (0, 200 or 1,000 mmol L-1 NaCl) conditions for 20 or 40 days. Then stratified seeds were incubated under different light or salinity conditions at daily (12/12 h) temperature regime of 10:25 °C for 20 days. For brown seeds, cold stratification was also part of the germination period. In contrast, almost no black seeds germinated during cold stratification. The longer the cold stratification, the better the subsequent germination of black seeds, regardless of light or salinity conditions. Light did not influence germination of brown seeds. Germination of cold-stratified black seeds was inhibited by darkness, especially when they were stratified in darkness. With an increase in salinity at the stage of cold stratification or germination, germination percentages of both seed morphs decreased. Combinational pre-treatments of cold stratification and salinity did not increase salt tolerance of dimorphic seeds in germination phase. Thus, light and salinity conditions during cold stratification partly interact with these conditions during germination stage and differentially affect germination of dimorphic seeds of S. aralocaspica. PMID:28828266

History of accidental hypothermia☆

PubMed Central

Guly, Henry

2011-01-01

Death from exposure to cold has been recognised for thousands of years but hypothermia as a clinical condition was not generally recognised until the mid-20th century and then only in extreme conditions such as immersion in cold water or snow. In the UK, hypothermia in less extreme conditions was not generally recognised until the 1960s. Recognition of hypothermia required the temperature to be measured and this did not become a clinical tool until the late 1800s and it was not used routinely until the early 1900s. Although John Hunter and James Curry did some physiological experiments in the 1700s, detailed physiological experiments were not done until the early 20th century and the use of therapeutic hypothermia for malignancy and in anaesthesia in the 1930s and 1940s provided more impetus for investigating the physiology of hypothermia in humans and familiarising the medical profession with measuring core temperatures. PMID:21036455

Taking one for the team: Physiological trajectories of painful intergroup retaliation.

PubMed

Niedbala, Elizabeth M; Hohman, Zachary P; Harris, Breanna N; Abide, Alexandra C

2018-06-13

Retaliating against a threatening outgroup offers group members specific rewards, such as restored group esteem, a reduction in anger, and a sense of gratification. Because retaliation is rewarding, group members may appraise an attack on the outgroup to be beneficial, even if it feels physically painful. We hypothesized that group members would be more willing to endure pain to retaliate against a threatening outgroup, and that appraising the painful retaliation as rewarding would down-regulate their physiological stress response to pain. Participants were manipulated to feel threatened by a rival group and then completed the cold-pressor. During the cold-pressor, participants either retaliated against the outgroup or not. Results showed that retaliation inhibited physiological responses to pain, alleviated intergroup anger, and felt less aversive. We propose that these responses are caused by a cognitive reappraisal of pain, where painful retaliation is expected to be rewarding instead of threatening. Copyright © 2017. Published by Elsevier Inc.

Geographic variation in the association between exploratory behavior and physiology in rufous-collared sparrows.

PubMed

Maldonado, Karin; van Dongen, Wouter F D; Vásquez, Rodrigo A; Sabat, Pablo

2012-01-01

Increasing research has attempted to clarify the links between animal personality and physiology. However, the mechanisms driving this association remain largely unknown, and knowledge of how ecological factors may affect its direction and strength is scant. In this study, we quantified variation in the association between exploratory behavior, basal metabolic rate (BMR), and total evaporative water loss (TEWL) in rufous-collared sparrows (Zonotrichia capensis) inhabiting desert, Mediterranean, and cold-temperate climates. We found that the exploratory behavior score was highest in birds from the cold-temperate site, which was characterized by a moderate level of ecological variability (seasonality). Moreover, the association between exploratory behavior and physiological variables differed among localities. Only birds from the Mediterranean site showed a positive correlation between exploratory behavior and BMR. We found no association between exploration and TEWL at any study site. Our findings suggest that differences in the ecological conditions experienced by each sparrow population result in a particular combination of behavioral and physiological traits. An understanding of this intraspecific variation along ecological gradients provides unique insights into how specific ecological conditions affect the coupling of behavioral and physiological traits and the mechanisms underlying that relationship.

Prediction of facial cooling while walking in cold wind.

PubMed

Tikuisis, Peter; Ducharme, Michel B; Brajkovic, Dragan

2007-09-01

A dynamic model of cheek cooling has been modified to account for increased skin blood circulation of individuals walking in cold wind. This was achieved by modelling the cold-induced vasodilation response to cold as a varying blood perfusion term, which provided a source of convective heat to the skin tissues of the model. Physiologically-valid blood perfusion was fitted to replicate the cheek skin temperature responses of 12 individuals experimentally exposed to air temperatures from -10 to 10 degrees C at wind speeds from 2 to 8 ms(-1). Resultant cheek skin temperatures met goodness-of-fit criteria and implications on wind chill predictions are discussed.

Proteome profiling reveals insights into cold-tolerant growth in sea buckthorn.

PubMed

He, Caiyun; Gao, Guori; Zhang, Jianguo; Duan, Aiguo; Luo, Hongmei

2016-01-01

Low temperature is one of the crucial environmental factors limiting the productivity and distribution of plants. Sea buckthorn ( Hippophae rhamnoides L.), a well recognized multipurpose plant species, live successfully in in cold desert regions. But their molecular mechanisms underlying cold tolerance are not well understood. Physiological and biochemical responses to low-temperature stress were studied in seedlings of sea buckthorn. Differentially expressed protein spots were analyzed using multiplexing fluorescent two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) coupled with matrix-assisted laser desorption/ionization (MALDI) time-of-flight/time-of-flight (TOF/TOF) mass spectrometry (MS), the concentration of phytohormone was measured using enzyme-linked immunosorbent assay, and a spectrophotometric assay was used to measure enzymatic reactions. With the increase of cold stress intensity, the photosynthesis rate, transpiration rate, stomatal conductance in leaves and contents of abscisic acid (ABA) and indole acetic acid (IAA) in roots decreased significantly; however, water-use efficiency, ABA and zeatin riboside in leaves increased significantly, while cell membrane permeability, malondialdehyde and IAA in leaves increased at 7 d and then decreased at 14 d. DIGE and MS/MS analysis identified 32 of 39 differentially expressed protein spots under low-temperature stress, and their functions were mainly involved in metabolism, photosynthesis, signal transduction, antioxidative systems and post-translational modification. The changed protein abundance and corresponding physiological-biochemical response shed light on the molecular mechanisms related to cold tolerance in cold-tolerant plants and provide key candidate proteins for genetic improvement of plants.

Cold Plasmas for Biofilm Control: Opportunities and Challenges.

PubMed

Gilmore, Brendan F; Flynn, Padrig B; O'Brien, Séamus; Hickok, Noreen; Freeman, Theresa; Bourke, Paula

2018-06-01

Bacterial biofilm infections account for a major proportion of chronic and medical device associated infections in humans, yet our ability to control them is compromised by their inherent tolerance to antimicrobial agents. Cold atmospheric plasma (CAP) represents a promising therapeutic option. CAP treatment of microbial biofilms represents the convergence of two complex phenomena: the production of a chemically diverse mixture of reactive species and intermediates, and their interaction with a heterogeneous 3D interface created by the biofilm extracellular polymeric matrix. Therefore, understanding these interactions and physiological responses to CAP exposure are central to effective management of infectious biofilms. We review the unique opportunities and challenges for translating CAP to the management of biofilms. Copyright © 2018. Published by Elsevier Ltd.

[Effect of warm and cold honey solutions on acid-forming function of the stomach].

PubMed

Kas'ianenko, V I; Selezneva, E Ia; Markarova, N V

2002-01-01

Apitherapy is treatment of diseases with biologically active products of bee-keeping (BAPB), which is developing in an intensive way all over the world. The interest in apitherapy is explained, on the one hand, by a great number of natural compounds produced by bees as a result of their vital functions and having high physiological activity, and on the other hand, by the universal nature of bees occurrence and comparative simplicity of getting the bee-keeping products. In apitherapy literature many authors point to the fact that honey has an impact on gastric secretion: a cold honey solution stimulates, and a warm one inhibits acid excretion. Yet there are no results of studies confirming this action in all publications.

Conflicts of thermal adaptation and fever--a cybernetic approach based on physiological experiments.

PubMed

Werner, J; Beckmann, U

1998-01-01

Cold adaptation aims primarily at a better economy, i.e., preservation of energy often at the cost of a lower mean body temperature during cold stress, whereas heat adaptation whether achieved by exposure to a hot environment or by endogenous heat produced by muscle exercise, often brings about a higher efficiency of control, i.e., a lower mean body temperature during heat stress, at the cost of a higher water loss. While cold adaptation is beneficial in a cold environment, it may constitute a detrimental factor for exposure to a hot environment, mainly because of morphological adaptation. Heat adaptation may be maladaptive for cold exposure, mainly because of functional adaptation. Heat adaptation clearly is best suited to avoid higher body temperatures in fever, no matter which environmental conditions prevail. On the other hand, cold adaptation is detrimental for coping with fever in hot environment. Yet, in the cold, preceding cold adaptation may, because of reduced metabolic heat production, result in lower febrile increase of body temperature. Apparently controversial effects and results may be analyzed in the framework of a cybernetic approach to the main mechanisms of thermal adaptation and fever. Morphological adaptations alter the properties of the heat transfer characteristics of the body ("passive system"), whereas functional adaptation and fever concern the subsystems of control, namely sensors, integrative centers and effectors. In a closed control-loop the two types of adaptation have totally different consequences. It is shown that the experimental results are consistent with the predictions of such an approach.

Comparative proteomic and metabolomic analyses reveal mechanisms of improved cold stress tolerance in bermudagrass (Cynodon dactylon (L.) Pers.) by exogenous calcium.

PubMed

Shi, Haitao; Ye, Tiantian; Zhong, Bao; Liu, Xun; Chan, Zhulong

2014-11-01

As an important second messenger, calcium is involved in plant cold stress response, including chilling (<20 °C) and freezing (<0 °C). In this study, exogenous application of calcium chloride (CaCl2 ) improved both chilling and freezing stress tolerances, while ethylene glycol-bis-(β-aminoethyl) ether-N,N,N,N-tetraacetic acid (EGTA) reversed CaCl2 effects in bermudagrass (Cynodon dactylon (L.) Pers.). Physiological analyses showed that CaCl2 treatment alleviated the reactive oxygen species (ROS) burst and cell damage triggered by chilling stress, via activating antioxidant enzymes, non-enzymatic glutathione antioxidant pool, while EGTA treatment had the opposite effects. Additionally, comparative proteomic analysis identified 51 differentially expressed proteins that were enriched in redox, tricarboxylicacid cycle, glycolysis, photosynthesis, oxidative pentose phosphate pathway, and amino acid metabolisms. Consistently, 42 metabolites including amino acids, organic acids, sugars, and sugar alcohols were regulated by CaCl2 treatment under control and cold stress conditions, further confirming the common modulation of CaCl2 treatment in carbon metabolites and amino acid metabolism. Taken together, this study reported first evidence of the essential and protective roles of endogenous and exogenous calcium in bermudagrass response to cold stress, partially via activation of the antioxidants and modulation of several differentially expressed proteins and metabolic homeostasis in the process of cold acclimation. © 2014 Institute of Botany, Chinese Academy of Sciences.

Anthocyanin-rich Aronia melanocarpa extract improves body temperature maintenance in healthy women with a cold constitution.

PubMed

Sonoda, Keisuke; Aoi, Wataru; Iwata, Tomoaki; Li, Yanmei

2013-01-01

Specific anthocyanin-rich dietary factors have been shown to improve metabolic functions associated with thermogenesis in animal studies. Aronia melanocarpa, commonly known as wild chokeberry, contains a high level of anthocyanin that would be expected to maintain body temperature through thermogenesis. We here investigated the effects of Aronia melanocarpa extracts on body temperature and peripheral blood flow in healthy women with a cold constitution. A pre/post comparison trial was performed in 11 women with a cold constitution, who were taking Aronia melanocarpa extracts (150 mg/day) for 4 weeks. Physiological and biochemical parameters, along with psychological tests were examined. The subjects' body surface temperature was significantly higher in the post-trial than in the pre-trial. In psychological tests, factors related to cold were significantly improved by Aronia intake. On the other hand, peripheral blood flow was not affected by Aronia supplementation. Plasma noradrenalin level was significantly elevated by Aronia intake, and subjects with a higher level of 8-hydroxy-2'-deoxyguanosine in the pre-trial showed decreased levels in the post-trial. These data suggest that dietary Aronia melanocarpa extract improves the maintenance of body temperature in healthy women with a cold constitution, which may be mediated by noradrenalin and oxidative stress levels.

Depressive symptoms and attenuated physiological reactivity to laboratory stressors.

PubMed

Schwerdtfeger, Andreas; Rosenkaimer, Ann-Kathrin

2011-07-01

There is evidence that depressive symptoms are associated with attenuated physiological reactivity to active stressors. However, it is not known whether blunted reactivity in depressed individuals is stressor-specific. We examined cardiovascular and electrodermal reactivity in non-clinical participants with varying levels of depressive symptoms to different active and passive stressors. Depressive symptoms were inversely related to both blood pressure and skin conductance reactivity during a public speaking task and the viewing of the speech video. However, no effects were found during a cold pressor task. Together these findings suggest that depressive symptoms are related to attenuated sympathetic nervous system reactivity in response to self-relevant stressors. Copyright © 2011 Elsevier B.V. All rights reserved.

Osmotic and elastic adjustments in cold desert shrubs differing in rooting depth: coping with drought and subzero temperatures

Treesearch

Fabian G. Scholz; Sandra J. Bucci; Nadia Arias; Frederick C. Meinzer; Guillermo Goldstein

2012-01-01

Physiological adjustments to enhance tolerance or avoidance of summer drought and winter freezing were studied in shallow- to deep-rooted Patagonian cold desert shrubs. We measured leaf water potential, osmotic potential, tissue elasticity, stem hydraulic characteristics, and stomatal conductance across species throughout the year, and assessed tissue damage by subzero...

[The acclimatization to extreme environments and its physiological mechanisms].

PubMed

Wang, Hai; Liu, Wei; Yang, Dan-Feng; Zhao, Xiao-Ling; Long, Chao-Liang; Yin, Zhao-Yun; Liu, Jia-Ying

2012-11-01

Acclimatization is a process of biological adaptation when exposed to environmental factors such as hypoxia, cold and heat for prolonged periods of time, where non-genetical variations play a role in allowing subjects to tolerate hypoxic, cold or hot environments. This review focuses on the characteristics and mechanisms of acclimatization found through major research advances by our institute. First, the mechanisms underlying the acclimatization to extreme environments are complex. In our investigations, the physiological changes of multiple systems including the nervous, circulatory, respiratory, and hemopoietic system were demonstrated when the acclimatization to hypoxia was developed, and the underlying significance of hypoxia-inducible factor-1 (HIF-1) was investigated. Second, it is suggested that the development of acclimatization to extreme environments is complicated. Hypoxia and cold coexist at high altitude. Our investigations revealed the characteristics of negative cross-relationship in the acclimatization to hypoxia and cold. And third, it is interesting for us to understand that acclimatization to extreme environments is transferable among individuals, and the characteristics of heat acclimatization-inducing factor (HAlF) were presented. The above findings will provide a theoretical guidance for protective operations and help to establish a solid foundation for future research related to acclimatization.

Winter variation in physiological status of cold stored and freshly lifted semi-evergreen quercus nigra seedlings

Treesearch

Rosa C. Goodman; Douglass F. Jacobs; Kent G. Apostol; Barrett C. Wilson; Emile S. Gardiner

2009-01-01

Water oak (Quercus nigra L.) is a tardily deciduous species commonly planted in afforestation projects in the Lower Mississippi River Alluvial Valley, USA. Field performance is often marked by low survival rates and top dieback, which may be associated with poor physiological quality of planting stock.

Physiological and Psychological Responses during Exercise and Recovery in a Cold Environment Is Gender-Related Rather Than Fabric-Related

PubMed Central

Cernych, Margarita; Baranauskiene, Neringa; Eimantas, Nerijus; Kamandulis, Sigitas; Daniuseviciute, Laura; Brazaitis, Marius

2017-01-01

We evaluated gender-specific effects of two types of undergarments on exercise-induced physiological and psychological stress and subsequent recovery in cold conditions for male and female participants. Ten healthy men and eleven healthy women (25.0 ± 1.5 versus 23.4 ± 1.2 years old, respectively) completed the experimental session twice with two different types of undergarments: polyester or merino wool leggings and long-sleeve tops; specifically, merino fabric had greater thermal resistance and water absorbency, and less water vapor as well as air permeability than polyester. Experimental sessions involved performing 1 h of exercise on a cycle ergometer at 8°C ambient temperature and 55% relative humidity, holding at 70–80 revolutions per minute and 60% of each participant’s predetermined maximal power output (assessed by maximal oxygen uptake test), followed by 1 h recovery in the same environment. Every 5 min during exercise and every 10 min during recovery, rectal temperature, heart rate, subjective ratings for thermal, shivering/sweating and clothing wetness sensations, and clothing next-to-skin and outer side surface temperature and humidity on the chest, back and thigh were recorded. All participants experienced high physiological stress (assessed by physiological strain index) during exercise. No significant gender differences were found in core temperature or heart rate changes during exercise, but women cooled down faster during recovery. Next-to-skin humidity was similar between genders and different garment sets during exercise and recovery, but such temperatures at the chest during exercise and at the thigh during exercise and recovery were lower in women with both sets of garments. Subjective thermal sensations were similar in all cases. In the last 20 min of cycling, women started to feel wetter than men (P < 0.05) for both garment sets. Shivering was reported as stronger in women in the last 10 min of recovery. Most of the changes in the garment microclimates during exercise and recovery in the cold were associated with gender-related differences rather than with fabric-related differences. PMID:28824518

Metabolic cold adaptation in fishes occurs at the level of whole animal, mitochondria and enzyme

PubMed Central

White, Craig R.; Alton, Lesley A.; Frappell, Peter B.

2012-01-01

Metabolic cold adaptation (MCA), the hypothesis that species from cold climates have relatively higher metabolic rates than those from warm climates, was first proposed nearly 100 years ago and remains one of the most controversial hypotheses in physiological ecology. In the present study, we test the MCA hypothesis in fishes at the level of whole animal, mitochondria and enzyme. In support of the MCA hypothesis, we find that when normalized to a common temperature, species with ranges that extend to high latitude (cooler climates) have high aerobic enzyme (citrate synthase) activity, high rates of mitochondrial respiration and high standard metabolic rates. Metabolic compensation for the global temperature gradient is not complete however, so when measured at their habitat temperature species from high latitude have lower absolute rates of metabolism than species from low latitudes. Evolutionary adaptation and thermal plasticity are therefore insufficient to completely overcome the acute thermodynamic effects of temperature, at least in fishes. PMID:22158960

Metabolic cold adaptation in fishes occurs at the level of whole animal, mitochondria and enzyme.

PubMed

White, Craig R; Alton, Lesley A; Frappell, Peter B

2012-05-07

Metabolic cold adaptation (MCA), the hypothesis that species from cold climates have relatively higher metabolic rates than those from warm climates, was first proposed nearly 100 years ago and remains one of the most controversial hypotheses in physiological ecology. In the present study, we test the MCA hypothesis in fishes at the level of whole animal, mitochondria and enzyme. In support of the MCA hypothesis, we find that when normalized to a common temperature, species with ranges that extend to high latitude (cooler climates) have high aerobic enzyme (citrate synthase) activity, high rates of mitochondrial respiration and high standard metabolic rates. Metabolic compensation for the global temperature gradient is not complete however, so when measured at their habitat temperature species from high latitude have lower absolute rates of metabolism than species from low latitudes. Evolutionary adaptation and thermal plasticity are therefore insufficient to completely overcome the acute thermodynamic effects of temperature, at least in fishes.

Enhanced thermogenesis in rats by Panax ginseng, multivitamins and minerals

NASA Astrophysics Data System (ADS)

Kumar, Ratan; Grover, S. K.; Divekar, H. M.; Gupta, A. K.; Shyam, Radhey; Srivastava, K. K.

1996-12-01

Substances which enhance endurance for physical and mental work and increase non-specific resistance to stress during a prolonged stay in physiologically adverse habitats are called ‘adaptogens’. Panax ginseng is well known for its anti-stress and adaptogenic properties. In the present study, adaptogenic activity by the intake of a herbo-vitamin-mineral preparation (HVMP) containing P. ginseng and multivitamin-mineral preparation (MVMP) was evaluated using the cold-hypoxia-restrained (C-H-R) animal model. The aim was to determine whether the cold tolerance and recovery from acute hypothermia mediated by P. ginseng was modified by simultaneous intake of additional vitamins and minerals. Results suggest that the adaptogenic effect of HVMP was more or less the sum total of its two components P. ginseng and MVMP. In HVMP, P. ginseng was found to be effective for developing resistance to cooling and MVMP helped in stimulating faster recovery from acute hypothermia.

Is distribution of cold stenotherms constrained by temperature? The case of the Arctic fairy shrimp (Branchinecta paludosa O.F. Müller 1788).

PubMed

Lindholm, M; Hessen, D O; Færøvig, P J; Rognerud, B; Andersen, T; Stordal, F

2015-10-01

Small water bodies in cold climate respond fast to global warming, and species adapted to such habitats may be valuable indicators for climate change. We investigated the geographical and physiological temperature limits of the Arctic fairy shrimp (Branchinecta paludosa), which is common in cold water arctic ponds, but at present retracts its range in alpine areas along its southern outreach of Norway. Seasonal logging of water temperatures along an altitudinal transect revealed an upper temperature limit of 12.7°C for its presence, which closely matched a calculated upper temperature limit of 12.9°C throughout its entire Norwegian range. Field data hence point to cold stenotherm features, which would be consistent with its Arctic, circumpolar distribution. Lab experiments, on the other hand, revealed a linear increase in respiration over 10-20°C. When fed ad libitum somatic growth increased with temperature, as well, without negative physiological impacts of higher temperatures. The absence of Branchinecta paludosa in ponds warmer than 13°C could still be due to a mismatch between temperature dependent metabolism and limited energy supply in these ultraoligotrophic water bodies. We discuss the concept of cold stenothermy in this context, and the impacts of regional warming on the future distribution of the Arctic fairy shrimp. Copyright © 2015 Elsevier Ltd. All rights reserved.

Physiological changes in women during exercise in cold environments

NASA Astrophysics Data System (ADS)

Murray, S. J.; Shephard, R. J.; Radomski, M. W. M.

1986-12-01

Both the stress of exercise and the stress of a cold environment have been shown to increase the mobilization and utilization of body fat, thereby reducing body fat stores. Much of the research has been done on either rats or male human subjects. The purpose of this research was to show the physiological changes which occur to young, relatively obese, women who exercised during five consecutive days, for 200 min per day, in each of three environmental, chamber conditions: (1) warm-warm (WW), +15‡C; (2) cold-cold (CC), -20‡C; and (3) cold-warm (CW), -20‡C ambient temperature, with +18‡C air pumped to face masks for warmed air breathing. Oxygen cost of exercise, respiratory quotients, energy intake and utilization, and body composition changes were measured before, during, and after each environmental condition. While the respiratory quotients and the skinfold measurements decreased in the colder conditions, the underwater weighing determined percentage body fat did not show the same decrement as the skinfold measures, indicating a possible translocation of body fat from the subcutaneous depots to the deep body fat depots. Body mass loss was significant (P<0.05) only in the WW condition. Thermogenesis would have been centred in the skeletal muscle and liver during the CW condition; however, with facial and upper airway cooling in the CC condition; brown adipose tissue (BAT) hypertrophy may be postulated at this more intense level of cold stress. Due to a greater stability of depot fat in the female, a longer cold exposure would be required to observe the fully developed BAT thermogenesis which would follow after the consequences of fat translocation which we have documented.

Protection against renal ischemia-reperfusion injury through hormesis? Dietary intervention versus cold exposure.

PubMed

Shushimita, Shushimita; Grefhorst, Aldo; Steenbergen, Jacobie; de Bruin, Ron W F; Ijzermans, Jan N M; Themmen, Axel P N; Dor, Frank J M F

2016-01-01

Dietary restriction (DR) and fasting (FA) induce robust protection against the detrimental effects of renal ischemia-reperfusion injury (I/RI). Several mechanisms of protection have been proposed, such as hormesis. Hormesis is defined as a life-supporting beneficial effect resulting from the cellular responses to single or multiple rounds of (mild) stress. The cold exposure (CE) model is a stress model similar to DR, and has been shown to have hormetic effects and has proved to increase longevity. CE is considered to be the most robust method to increase metabolism through activation of brown adipocytes. BAT has been considered important in etiology of obesity and its metabolic consequences. Since DR, FA, and CE models are proposed to work through hormesis, we investigated physiology of adipose tissue and effect on BAT in these models and compared them to ad libitum (AL) fed mice. We also studied the differential effect of these stress models on immunological changes, and effect of CE on renal I/RI. We show similar physiological changes in adiposity in male C57Bl/6 mice due to DR, FA and CE, but the CE mice were not protected against renal I/RI. The immunophenotypic changes observed in the CE mice were similar to the AL animals, in contrast to FA mice, that showed major immunophenotypic changes in the B and T cell development stages in primary and secondary lymphoid organs. Our findings thus demonstrate that DR, FA and CE are hormetic stress models. DR and FA protect against renal I/IR, whereas CE could not. Copyright © 2015 Elsevier Inc. All rights reserved.

Physiological Employment Standards III: physiological challenges and consequences encountered during international military deployments.

PubMed

Nindl, Bradley C; Castellani, John W; Warr, Bradley J; Sharp, Marilyn A; Henning, Paul C; Spiering, Barry A; Scofield, Dennis E

2013-11-01

Modern international military deployments in austere environments (i.e., Iraq and Afghanistan) place considerable physiological demands on soldiers. Significant physiological challenges exist: maintenance of physical fitness and body composition, rigors of external load carriage, environmental extremes (heat, cold, and altitude), medical illnesses, musculoskeletal injuries, traumatic brain injuries, post-traumatic stress disorder, and environmental exposure hazards (i.e., burn pits, vehicle exhaust, etc.). To date there is very little published research and no comprehensive reviews on the physiological effects of deployments. The purpose of this paper is to overview what is currently known from the literature related mainly to current military conflicts with regard to the challenges and consequences from deployments. Summary findings include: (1) aerobic capacity declines while muscle strength, power and muscular endurance appear to be maintained, (2) load carriage continues to tax the physical capacities of the Soldier, (3) musculoskeletal injuries comprise the highest proportion of all injury categories, (4) environmental insults occur from both terrestrial extremes and pollutant exposure, and (5) post-deployment concerns linger for traumatic brain injury and post-traumatic stress disorder. A full understanding of these responses will assist in identifying the most effective risk mitigation strategies to ensure deployment readiness and to assist in establishment of military employment standards.

Thermoregulation: long-term microwave effects. Final report 1 Feb 83-31 Jan 84

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adair, E.R.

1984-04-17

A pilot study investigated the consequences of chronic exposure to 2450-MHz CW microwaves, or sham exposure, in a cold (18 degC) environment on the thermoregulatory responses, both behavioral and physiological, of squirrel monkeys. Two animals exposed to microwaves exhibited responses that were little different from those measured in animals residing in thermoneutral environments while two sham-exposed animals sustained thermoregulatory deficits. These tentative findings require replication.

Changes in chemical components in the freshwater apple snail, Pomacea canaliculata (Gastropoda: Ampullariidae), in relation to the development of its cold hardiness.

PubMed

Matsukura, Keiichiro; Tsumuki, Hisaaki; Izumi, Yohei; Wada, Takashi

2008-04-01

The apple snail, Pomacea canaliculata, is an invasive freshwater snail. It increases its cold hardiness before winter. However, the physiological mechanism of cold hardiness in molluscs is poorly understood, especially in freshwater molluscs. In this study, we examined the changes in low molecular weight compounds, glycogen and lipids, in the body of P. canaliculata in association with the development of cold hardiness. When snails without cold hardiness were experimentally cold-acclimated, the amount of glycerol, glutamine, and carnosine increased, while glycogen and phenylalanine decreased. Overwintering cold-tolerant snails collected from a drained paddy field in November also showed increased glycerol in their bodies with decreasing glycogen concentration, compared to summer snails collected from a submerged field. Water content also decreased during the cold acclimation, although the water loss was minimal. These results indicate that the freshwater snail, P. canaliculata enhances cold hardiness by accumulation of some kinds of low molecular weight compounds in its body as some insects do. However, the actual function of each low molecular compound is still unknown.

Effect of farm and simulated laboratory cold environmental conditions on the performance and physiological responses of lactating dairy cows supplemented with bovine somatotropin (BST)

NASA Astrophysics Data System (ADS)

Becker, B. A.; Johnson, H. D.; Li, R.; Collier, R. J.

1990-09-01

A study was conducted to evaluate the effect of bovine somatotropin (BST) supplementation in twelve lactating dairy cows maintained in cold environmental conditions. Six cows were injected daily with 25 mg of BST; the other six were injected with a control vehicle. Cows were maintained under standard dairy management during mid-winter for 30 days. Milk production was recorded twice daily, and blood samples were taken weekly. Animals were then transferred to environmentally controlled chambers and exposed to cycling thermoneutral (15° to 20° C) and cycling cold (-5° to +5° C) temperatures for 10 days in a split-reversal design. Milk production, feed and water intake, body weights and rectal temperatures were monitored. Blood samples were taken on days 1, 3, 5, 8 and 10 of each period and analyzed for plasma triiodothyronine (T3), thyroxine (T4), cortisol, insulin and prolactin. Under farm conditions, BST-treated cows produced 11% more milk than control-treated cows and in environmentally controlled chambers produced 17.4% more milk. No differences due to BST in feed or water intake, body weights or rectal temperatures were found under laboratory conditions. Plasma T3 and insulin increased due to BST treatment while no effect was found on cortisol, prolactin or T4. The results showed that the benefits of BST supplementation in lactating dairy cows were achieved under cold environmental conditions.

Selective blockade of TRPA1 channel attenuates pathological pain without altering noxious cold sensation or body temperature regulation.

PubMed

Chen, Jun; Joshi, Shailen K; DiDomenico, Stanley; Perner, Richard J; Mikusa, Joe P; Gauvin, Donna M; Segreti, Jason A; Han, Ping; Zhang, Xu-Feng; Niforatos, Wende; Bianchi, Bruce R; Baker, Scott J; Zhong, Chengmin; Simler, Gricelda H; McDonald, Heath A; Schmidt, Robert G; McGaraughty, Steve P; Chu, Katharine L; Faltynek, Connie R; Kort, Michael E; Reilly, Regina M; Kym, Philip R

2011-05-01

Despite the increasing interest in TRPA1 channel as a pain target, its role in cold sensation and body temperature regulation is not clear; the efficacy and particularly side effects resulting from channel blockade remain poorly understood. Here we use a potent, selective, and bioavailable antagonist to address these issues. A-967079 potently blocks human (IC(50): 51 nmol/L, electrophysiology, 67 nmol/L, Ca(2+) assay) and rat TRPA1 (IC(50): 101 nmol/L, electrophysiology, 289 nmol/L, Ca(2+) assay). It is >1000-fold selective over other TRP channels, and is >150-fold selective over 75 other ion channels, enzymes, and G-protein-coupled receptors. Oral dosing of A-967079 produces robust drug exposure in rodents, and exhibits analgesic efficacy in allyl isothiocyanate-induced nocifensive response and osteoarthritic pain in rats (ED(50): 23.2 mg/kg, p.o.). A-967079 attenuates cold allodynia produced by nerve injury but does not alter noxious cold sensation in naive animals, suggesting distinct roles of TRPA1 in physiological and pathological states. Unlike TRPV1 antagonists, A-967079 does not alter body temperature. It also does not produce locomotor or cardiovascular side effects. Collectively, these data provide novel insights into TRPA1 function and suggest that the selective TRPA1 blockade may present a viable strategy for alleviating pain without untoward side effects. Copyright © 2011 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Cold air drainage flows subsidize montane valley ecosystem productivity.

PubMed

Novick, Kimberly A; Oishi, A Christopher; Miniat, Chelcy Ford

2016-12-01

In mountainous areas, cold air drainage from high to low elevations has pronounced effects on local temperature, which is a critical driver of many ecosystem processes, including carbon uptake and storage. Here, we leverage new approaches for interpreting ecosystem carbon flux observations in complex terrain to quantify the links between macro-climate condition, drainage flows, local microclimate, and ecosystem carbon cycling in a southern Appalachian valley. Data from multiple long-running climate stations and multiple eddy covariance flux towers are combined with simple models for ecosystem carbon fluxes. We show that cold air drainage into the valley suppresses local temperature by several degrees at night and for several hours before and after sunset, leading to reductions in growing season respiration on the order of ~8%. As a result, we estimate that drainage flows increase growing season and annual net carbon uptake in the valley by >10% and >15%, respectively, via effects on microclimate that are not be adequately represented in regional- and global-scale terrestrial ecosystem models. Analyses driven by chamber-based estimates of soil and plant respiration reveal cold air drainage effects on ecosystem respiration are dominated by reductions to the respiration of aboveground biomass. We further show that cold air drainage proceeds more readily when cloud cover and humidity are low, resulting in the greatest enhancements to net carbon uptake in the valley under clear, cloud-free (i.e., drought-like) conditions. This is a counterintuitive result that is neither observed nor predicted outside of the valley, where nocturnal temperature and respiration increase during dry periods. This result should motivate efforts to explore how topographic flows may buffer eco-physiological processes from macroscale climate change. © 2016 John Wiley & Sons Ltd.

Environmental stressors influencing hormones and systems physiology in cattle

PubMed Central

2014-01-01

Environmental stressors undoubtedly influence organismal biology, specifically the endocrine system that, in turn, impact cattle at the systems physiology level. Despite the significant advances in understanding the genetic determinants of the ideal dairy or beef cow, there is a grave lack of understanding of the systems physiology and effects of the environmental stressors that interfere with the endocrine system. This is a major problem because the lack of such knowledge is preventing advances in understanding gene-environment interactions and developing science-based solutions to these challenges. In this review, we synthesize the current knowledge on the nature of the major environmental stressors, such as climate (heat, cold, wind, and humidity), nutrition (feeds, feeding systems, and endocrine disruptors) and management (housing density and conditions, transportation, weaning practices). We summarize the impact of each one of these factors on cattle at the systems level, and provide solutions for the challenges. PMID:24996419

Changes in endogenous plant hormones and 'H-NMR profiles and signals in Styrax japonicus seeds as influenced by warm and cold stratification

USDA-ARS?s Scientific Manuscript database

Germination of Styrax japonicus Sieb. et. Zucc. seeds was promoted by warm stratification (WS) at around 20 °C followed by cold stratification (CS) at around 5oC. Biochemical and physiological changes in Styrax seeds during these WS and CS treatments were not investigated. The objective of this wo...

Inhibition of Listeria monocytogenes by Carnobacterium spp. strains in a simulated cold smoked fish system stored at 4 degrees C.

PubMed

Duffes, F; Leroi, F; Boyaval, P; Dousset, X

1999-03-01

Preservation of smoked salmon from bacterial spoilage, and especially from Listeria monocytogenes by bacteriocin producers is a promising challenge. Over a hundred lactic acid bacteria, isolated from commercial vacuum packaged cold smoked salmon, were screened for their antagonistic activity against L. innocua. Twenty-two strains were able to produce bacteriocin-like proteinaceous substances. These strains were characterized physiologically and biochemically as Carnobacterium strains. Three different groups were determined by pulsed-field gel electrophoresis after Sma I and Apa I DNA digestion. Peptidoglycan hydrolases patterns completed the characterization of these strains. All were confirmed as being Carnobacterium piscicola. Growth and bacteriocin production of three strains of each group and two well known bacteriocin producers (C. divergens V41 and C. piscicola V1) were tested in a simulated cold smoked fish system at 4 degrees C. These strains were able to reach 10(8) cfu ml(-1) in 21 days and to produce as much bacteriocin activities in the cold smoked fish system as in the rich media. Carnobacterium divergens V41 and C. piscicola V1 were the most effective strains in co-culture experiments, inhibiting L. monocytogenes as early as day 4, whereas C. piscicola SF668 inhibiting effect was observed at day 13. The potential for using such biopreservation treatments on whole smoked salmon is discussed.

Physiological changes in red spruce seedlings during a simulated winter thaw

Treesearch

P.G. Schaberg; J.B. Shane; G.J. Hawley; G.R. Strimbeck; D.H. DeHayes; P.F. Cali; J.R. Donnelly

1996-01-01

We evaluated net photosynthesis, respiration, leaf conductance, xylem pressure potential (XPP) and cold hardiness in red spruce (Picea rubens Sarg.) seedlings exposed to either a continuous thaw (CT) or a daytime thaw with freezing nights (FN) for 8 days during mid-winter. Physiological differences between CT and FN seedlings were evident for all...

Phospholipase C δ4 regulates cold sensitivity in mice.

PubMed

Yudin, Yevgen; Lutz, Brianna; Tao, Yuan-Xiang; Rohacs, Tibor

2016-07-01

The cold- and menthol-activated transient receptor potential melastatin 8 (TRPM8) channels are thought to be regulated by phospholipase C (PLC), but neither the specific PLC isoform nor the in vivo relevance of this regulation has been established. Here we identify PLCδ4 as the key PLC isoform involved in regulation of TRPM8 channels in vivo. We show that in small PLCδ4(-/-) TRPM8-positive dorsal root ganglion neurons cold, menthol and WS-12, a selective TRPM8 agonist, evoked significantly larger currents than in wild-type neurons, and action potential frequencies induced by menthol or by current injections were also higher in PLCδ4(-/-) neurons. PLCδ4(-/-) mice showed increased behavioural responses to evaporative cooling, and this effect was inhibited by a TRPM8 antagonist; behavioural responses to heat and mechanical stimuli were not altered. We provide evidence for the involvement of a specific PLC isoform in the regulation of cold sensitivity in mice by regulating TRPM8 activity. The transient receptor potential melastatin 8 (TRPM8) ion channel is a major sensor of environmental low temperatures. Ca(2+) -induced activation of phospholipase C (PLC) has been implied in the regulation of TRPM8 channels during menthol- and cold-induced desensitization in vitro. Here we identify PLCδ4 as the key PLC isoform involved in regulation of TRPM8 in sensory dorsal root ganglion (DRG) neurons. We identified two TRPM8-positive neuronal subpopulations, based on their cell body size. Most TRPM8-positive small neurons also responded to capsaicin, and had significantly larger menthol-induced inward current densities than medium-large cells, most of which did not respond to capsaicin. Small, but not medium-large, PLCδ4(-/-) neurons showed significantly larger currents induced by cold, menthol or WS-12, a specific TRPM8 agonist, compared to wild-type (WT) neurons, but TRPM8 protein levels were not different between the two groups. In current-clamp experiments small neurons had more depolarized resting membrane potentials, and required smaller current injections to generate action potentials (APs) than medium-large cells. In small PLCδ4(-/-) neurons, menthol application induced larger depolarizations and generation of APs with frequencies significantly higher compared to WT neurons. In behavioural experiments PLCδ4(-/-) mice showed greater sensitivity to evaporative cooling by acetone than control animals. Pretreatment with the TRPM8 antagonist PBMC reduced cold-induced responses, and the effect was more pronounced in the PLCδ4(-/-) group. Heat and mechanical sensitivity of the PLCδ4(-/-) mice was not different from WT animals. Our data support the involvement of PLCδ4 in the regulation of TRPM8 channel activity in vivo. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Ghrelin-induced hypothermia: A Physiological basis but no clinical risk

PubMed Central

Wiedmer, Petra; Strasser, Florian; Horvath, Tamas L.; Blum, David; DiMarchi, Richard; Lutz, Thomas; Schürmann, Annette; Joost, Hans-Georg; Tschöp, Matthias H.; Tong, Jenny

2011-01-01

Ghrelin increases food intake and decreases energy expenditure, promoting a positive energy balance. We observed a single case of serious hypothermia during sustained ghrelin treatment in a male subject, suggesting that ghrelin may play a role in the regulation of body temperature. We therefore investigated the effect of ghrelin treatment on body temperature in rodents and humans under controlled conditions. Intriguingly, we could demonstrate ghrelin binding in axon terminals of the medial preoptic area of the hypothalamus located in the vicinity of cold-sensitive neurons. This localization of ghrelin receptors provides a potential anatomical basis for the regulation of body temperature by ghrelin. However, our follow-up studies also indicated that neither a chronic i.c.v. application of ghrelin in rats, nor a single s.c. injection under cold exposure in mice resulted in a relevant decrease in body core temperature. In addition, a four-hour intravenous ghrelin infusion did not decrease body surface temperature in healthy humans. We concluded that while there is a theoretical molecular basis for ghrelin to modify body temperature in mammals, its magnitude is irrelevant under physiologic circumstances. Hypothermia is not likely to represent a serious risk associated with this agent and pathway. PMID:21513721

The capacity to maintain ion and water homeostasis underlies interspecific variation in Drosophila cold tolerance

PubMed Central

MacMillan, Heath A.; Andersen, Jonas L.; Davies, Shireen A.; Overgaard, Johannes

2015-01-01

Many insects, including Drosophila, succumb to the physiological effects of chilling at temperatures well above those causing freezing. Low temperature causes a loss of extracellular ion and water homeostasis in such insects, and chill injuries accumulate. Using an integrative and comparative approach, we examined the role of ion and water balance in insect chilling susceptibility/ tolerance. The Malpighian tubules (MT), of chill susceptible Drosophila species lost [Na+] and [K+] selectivity at low temperatures, which contributed to a loss of Na+ and water balance and a deleterious increase in extracellular [K+]. By contrast, the tubules of chill tolerant Drosophila species maintained their MT ion selectivity, maintained stable extracellular ion concentrations, and thereby avoided injury. The most tolerant species were able to modulate ion balance while in a cold-induced coma and this ongoing physiological acclimation process allowed some individuals of the tolerant species to recover from chill coma during low temperature exposure. Accordingly, differences in the ability to maintain homeostatic control of water and ion balance at low temperature may explain large parts of the wide intra- and interspecific variation in insect chilling tolerance. PMID:26678786

[Frequency of the common cold in healthy subjects during exposure to a lectin-rich and a lectin-poor mistletoe preparation in a randomized, double-blind, placebo-controlled study].

PubMed

Huber, R; Klein, R; Lüdtke, R; Werner, M

2001-12-01

Mistletoe preparations have immunomodulatory properties in vitro and in vivo. We wanted to investigate whether or not these properties have an effect on the frequency of the common cold in healthy subjects. During a randomized, placebo-controlled, double-blind study 16 volunteers received the mistletoe lectin(ML)-poor preparation Iscador Pini(R) (IP), 16 the ML-rich preparation Iscador Quercus spezial(R) (IQ), and 16 placebo (physiological saline solution) twice a week subcutaneously for 12 weeks. Weekly during weeks 1-12 and finally at week 26, a careful history of common cold symptoms was taken. Because the frequency of the common cold was not the main outcome criterion in this study, the number of cases needed to treat was not adjusted to this criterion. The mean frequency of the common cold during the 12 weeks of injection was 1.5 in the placebo, 1.4 in the IP and 1.1 in the IQ group. During this period in 2.3 (placebo), 1.9 (IP) and 1.4 (IQ) weeks symptoms of common cold were present. The difference in favor to IQ lasted until the end of the observation period in week 26. It was, however, not significant. Leukocyte and granulocyte count as well as C-reactive protein were not different between the groups. The study showed a trend (p = 0.4, exact Kruskal- Wallis test) to reduced frequency and duration of the common cold in subjects who were exposed to IQ. Copyright 2001 S. Karger GmbH, Freiburg

The physiologic basis and clinical applications of cryotherapy and thermotherapy for the pain practitioner.

PubMed

Nadler, Scott F; Weingand, Kurt; Kruse, Roger J

2004-07-01

Cryotherapy and thermotherapy are useful adjuncts for the treatment of musculoskeletal injuries. Clinicians treating these conditions should be aware of current research findings regarding these modalities, because their choice of modality may affect the ultimate outcome of the patient being treated. Through a better understanding of these modalities, clinicians can optimize their present treatment strategies. Although cold and hot treatment modalities both decrease pain and muscle spasm, they have opposite effects on tissue metabolism, blood flow, inflammation, edema, and connective tissue extensibility. Cryotherapy decreases these effects while thermotherapy increases them. Continuous low-level cryotherapy and thermotherapy are newer concepts in therapeutic modalities. Both modalities provide significant pain relief with a low side-effect profile. Contrast therapy, which alternates between hot and cold treatment modalities, provides no additional therapeutic benefits compared with cryotherapy or thermotherapy alone. Complications of cryotherapy include nerve damage, frostbite, Raynaud's phenomenon, cold-induced urticaria, and slowed wound healing. With thermotherapy, skin burns may occur, especially in patients with diabetes mellitus, multiple sclerosis, poor circulation, and spinal cord injuries. In individuals with rheumatoid arthritis, deep-heating modalities should be used with caution because increased inflammation may occur. Whirlpool and other types of hydrotherapy have caused infections of the skin, urogenital, and pulmonary systems. Additionally, ultrasound should not be used in patients with joint prostheses.

Systemic Cold Stress Adaptation of Chlamydomonas reinhardtii*

PubMed Central

Valledor, Luis; Furuhashi, Takeshi; Hanak, Anne-Mette; Weckwerth, Wolfram

2013-01-01

Chlamydomonas reinhardtii is one of the most important model organisms nowadays phylogenetically situated between higher plants and animals (Merchant et al. 2007). Stress adaptation of this unicellular model algae is in the focus because of its relevance to biomass and biofuel production. Here, we have studied cold stress adaptation of C. reinhardtii hitherto not described for this algae whereas intensively studied in higher plants. Toward this goal, high throughput mass spectrometry was employed to integrate proteome, metabolome, physiological and cell-morphological changes during a time-course from 0 to 120 h. These data were complemented with RT-qPCR for target genes involved in central metabolism, signaling, and lipid biosynthesis. Using this approach dynamics in central metabolism were linked to cold-stress dependent sugar and autophagy pathways as well as novel genes in C. reinhardtii such as CKIN1, CKIN2 and a hitherto functionally not annotated protein named CKIN3. Cold stress affected extensively the physiology and the organization of the cell. Gluconeogenesis and starch biosynthesis pathways are activated leading to a pronounced starch and sugar accumulation. Quantitative lipid profiles indicate a sharp decrease in the lipophilic fraction and an increase in polyunsaturated fatty acids suggesting this as a mechanism of maintaining membrane fluidity. The proteome is completely remodeled during cold stress: specific candidates of the ribosome and the spliceosome indicate altered biosynthesis and degradation of proteins important for adaptation to low temperatures. Specific proteasome degradation may be mediated by the observed cold-specific changes in the ubiquitinylation system. Sparse partial least squares regression analysis was applied for protein correlation network analysis using proteins as predictors and Fv/Fm, FW, total lipids, and starch as responses. We applied also Granger causality analysis and revealed correlations between proteins and metabolites otherwise not detectable. Twenty percent of the proteins responsive to cold are uncharacterized proteins. This presents a considerable resource for new discoveries in cold stress biology in alga and plants. PMID:23564937

Coping with thermal challenges: physiological adaptations to environmental temperatures.

PubMed

Tattersall, Glenn J; Sinclair, Brent J; Withers, Philip C; Fields, Peter A; Seebacher, Frank; Cooper, Christine E; Maloney, Shane K

2012-07-01

Temperature profoundly influences physiological responses in animals, primarily due to the effects on biochemical reaction rates. Since physiological responses are often exemplified by their rate dependency (e.g., rate of blood flow, rate of metabolism, rate of heat production, and rate of ion pumping), the study of temperature adaptations has a long history in comparative and evolutionary physiology. Animals may either defend a fairly constant temperature by recruiting biochemical mechanisms of heat production and utilizing physiological responses geared toward modifying heat loss and heat gain from the environment, or utilize biochemical modifications to allow for physiological adjustments to temperature. Biochemical adaptations to temperature involve alterations in protein structure that compromise the effects of increased temperatures on improving catalytic enzyme function with the detrimental influences of higher temperature on protein stability. Temperature has acted to shape the responses of animal proteins in manners that generally preserve turnover rates at animals' normal, or optimal, body temperatures. Physiological responses to cold and warmth differ depending on whether animals maintain elevated body temperatures (endothermic) or exhibit minimal internal heat production (ectothermic). In both cases, however, these mechanisms involve regulated neural and hormonal over heat flow to the body or heat flow within the body. Examples of biochemical responses to temperature in endotherms involve metabolic uncoupling mechanisms that decrease metabolic efficiency with the outcome of producing heat, whereas ectothermic adaptations to temperature are best exemplified by the numerous mechanisms that allow for the tolerance or avoidance of ice crystal formation at temperatures below 0°C. 2012 American Physiological Society. Compr Physiol 2:2037-2061, 2012.

Predicting worsening asthma control following the common cold

PubMed Central

Walter, Michael J.; Castro, Mario; Kunselman, Susan J.; Chinchilli, Vernon M; Reno, Melissa; Ramkumar, Thiruvamoor P.; Avila, Pedro C.; Boushey, Homer A.; Ameredes, Bill T.; Bleecker, Eugene R.; Calhoun, William J.; Cherniack, Reuben M.; Craig, Timothy J.; Denlinger, Loren C.; Israel, Elliot; Fahy, John V.; Jarjour, Nizar N.; Kraft, Monica; Lazarus, Stephen C.; Lemanske, Robert F.; Martin, Richard J.; Peters, Stephen P.; Ramsdell, Joe W.; Sorkness, Christine A.; Rand Sutherland, E.; Szefler, Stanley J.; Wasserman, Stephen I.; Wechsler, Michael E.

2008-01-01

The asthmatic response to the common cold is highly variable and early characteristics that predict worsening of asthma control following a cold have not been identified. In this prospective multi-center cohort study of 413 adult subjects with asthma, we used the mini-Asthma Control Questionnaire (mini-ACQ) to quantify changes in asthma control and the Wisconsin Upper Respiratory Symptom Survey-21 (WURSS-21) to measure cold severity. Univariate and multivariable models examined demographic, physiologic, serologic, and cold-related characteristics for their relationship to changes in asthma control following a cold. We observed a clinically significant worsening of asthma control following a cold (increase in mini-ACQ of 0.69 ± 0.93). Univariate analysis demonstrated season, center location, cold length, and cold severity measurements all associated with a change in asthma control. Multivariable analysis of the covariates available within the first 2 days of cold onset revealed the day 2 and the cumulative sum of the day 1 and 2 WURSS-21 scores were significant predictors for the subsequent changes in asthma control. In asthmatic subjects the cold severity measured within the first 2 days can be used to predict subsequent changes in asthma control. This information may help clinicians prevent deterioration in asthma control following a cold. PMID:18768579

History of accidental hypothermia.

PubMed

Guly, Henry

2011-01-01

Death from exposure to cold has been recognised for thousands of years but hypothermia as a clinical condition was not generally recognised until the mid-20th century and then only in extreme conditions such as immersion in cold water or snow. In the UK, hypothermia in less extreme conditions was not generally recognised until the 1960s. Recognition of hypothermia required the temperature to be measured and this did not become a clinical tool until the late 1800s and it was not used routinely until the early 1900s. Although John Hunter and James Curry did some physiological experiments in the 1700s, detailed physiological experiments were not done until the early 20th century and the use of therapeutic hypothermia for malignancy and in anaesthesia in the 1930s and 1940s provided more impetus for investigating the physiology of hypothermia in humans and familiarising the medical profession with measuring core temperatures. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Characterization of urge to cough and cough symptoms associated with the common cold: results of a US internet survey.

PubMed

Eccles, Ron; Dicpinigaitis, Peter; Turner, Ronald B; Druce, Howard M; Adeleke, Maryann; Mann, Ashley L

2016-06-01

Our knowledge of cough physiology is limited despite years of study. Even less is known about the sensation of urge to cough. Given that limited clinical data are available about urge to cough and cough attributes during a common cold, we sought to gain insights into experiences and perceptions related to these symptoms. An internet survey consisting of 51 questions was fielded in the United States. Eligible survey participants included men and women aged 18 years and older who had suffered from a cold with cough within the three months preceding the survey. Participants who confirmed suffering from recurrent cough, asthma, chronic bronchitis, chronic obstructive pulmonary disease, cystic fibrosis, or gastrointestinal reflux were excluded. Of 19,530 initial respondents, 8011 had a cold in the past three months. Of these, 6484 (81%) had experienced cough symptoms; 2708 respondents with cough due to cold and no exclusionary condition made up the analysis sample. Most respondents (62%) reported that cough developed one to two days after the onset of cold symptoms, and 45% felt that cough worsened their other cold symptoms. In 69% of respondents, cough outlasted other cold symptoms. Urge to cough was reported by 98% of respondents, and among these respondents, 64% described it as uncontrollable and 65% rated severity as moderate. More than half of respondents (57%) considered the sensation of urge to cough and the act of coughing as equally bothersome. Although urge to cough and inability to control cough were the most bothersome aspects of cough due to cold, few (<20%) respondents asked healthcare providers for treatment recommendations. Symptoms of urge to cough and cough are common and have a significant impact on cold sufferers. Understanding attributes of these symptoms may provide insights for effective management and the development of novel treatment strategies.

Precooling treatments induce resistance of Anastrepha ludens eggs to quarantine treatments of high-pressure processing combined with cold.

PubMed

Castañón-Rodríguez, J F; Velazquez, G; Montoya, P; Vázquez, M; Ramírez, J A

2014-04-01

High-pressure processing (HPP) combined with heat or cold has been proposed as an alternative quarantine process for Mexican fruit fly Anastrepha ludens Loew (Diptera: Tephritidae). HPP conditions at levels higher than 100 MPa applied to destroy eggs and larvae can also affect the postharvest physiology of the fruits. HPP at pressure levels in the range of 50-100 MPa is recommended. Eggs have been reported as being more resistant to HPP than larvae. Therefore, the objective of this study was to assess the effect of a precooling treatment on the biological viability of A. ludens eggs treated by HPP at 0 degrees C. The capability of nondestroyed eggs to develop and reproduce was also evaluated. One-, 2-, 3-, and 4-d-old eggs were precooled in ice water for 0 (control) 3, 6, 12, or 24 h and then pressurized at 50, 70, or 90 MPa for 0, 3, 6, or 9 min at 0 degrees C. The hatching capability of pressurized eggs was evaluated. The most lethal effect of HPP on nonprecooled eggs (0 h) was obtained at 90 MPa for 9 min, destroying all eggs except for the 3-d-old ones, which showed an 11.8% hatch rate. Precooling treatment improved the hatch rate of eggs ranging from 4 to 50% depending on precooling conditions. The main effect was observed after 6 h. These results suggest that precooling modified the biochemistry and physiology of eggs, improving their resistance to HPP treatments.

Cardiovascular function, compliance, and connective tissue remodeling in the turtle, Trachemys scripta, following thermal acclimation

PubMed Central

Keen, Adam N.; Crossley, Dane A.

2016-01-01

Low temperature directly alters cardiovascular physiology in freshwater turtles, causing bradycardia, arterial hypotension, and a reduction in systemic blood pressure. At the same time, blood viscosity and systemic resistance increase, as does sensitivity to cardiac preload (e.g., via the Frank-Starling response). However, the long-term effects of these seasonal responses on the cardiovascular system are unclear. We acclimated red-eared slider turtles to a control temperature (25°C) or to chronic cold (5°C). To differentiate the direct effects of temperature from a cold-induced remodeling response, all measurements were conducted at the control temperature (25°C). In anesthetized turtles, cold acclimation reduced systemic resistance by 1.8-fold and increased systemic blood flow by 1.4-fold, resulting in a 2.3-fold higher right to left (R-L; net systemic) cardiac shunt flow and a 1.8-fold greater shunt fraction. Following a volume load by bolus injection of saline (calculated to increase stroke volume by 5-fold, ∼2.2% of total blood volume), systemic resistance was reduced while pulmonary blood flow and systemic pressure increased. An increased systemic blood flow meant the R-L cardiac shunt was further pronounced. In the isolated ventricle, passive stiffness was increased following cold acclimation with 4.2-fold greater collagen deposition in the myocardium. Histological sections of the major outflow arteries revealed a 1.4-fold higher elastin content in cold-acclimated animals. These results suggest that cold acclimation alters cardiac shunting patterns with an increased R-L shunt flow, achieved through reducing systemic resistance and increasing systemic blood flow. Furthermore, our data suggests that cold-induced cardiac remodeling may reduce the stress of high cardiac preload by increasing compliance of the vasculature and decreasing compliance of the ventricle. Together, these responses could compensate for reduced systolic function at low temperatures in the slider turtle. PMID:27101300

Differential expression and emerging functions of non-coding RNAs in cold adaptation.

PubMed

Frigault, Jacques J; Morin, Mathieu D; Morin, Pier Jr

2017-01-01

Several species undergo substantial physiological and biochemical changes to confront the harsh conditions associated with winter. Small mammalian hibernators and cold-hardy insects are examples of natural models of cold adaptation that have been amply explored. While the molecular picture associated with cold adaptation has started to become clearer in recent years, notably through the use of high-throughput experimental approaches, the underlying cold-associated functions attributed to several non-coding RNAs, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), remain to be better characterized. Nevertheless, key pioneering work has provided clues on the likely relevance of these molecules in cold adaptation. With an emphasis on mammalian hibernation and insect cold hardiness, this work first reviews various molecular changes documented so far in these processes. The cascades leading to miRNA and lncRNA production as well as the mechanisms of action of these non-coding RNAs are subsequently described. Finally, we present examples of differentially expressed non-coding RNAs in models of cold adaptation and elaborate on the potential significance of this modulation with respect to low-temperature adaptation.

Evaluation of Physiological and Psychological Impairment of Human Performance in Cold Stressed Subjects

DTIC Science & Technology

1993-06-05

t 1 Cold-. 5- a) E 10- - SST 1- 5- 0 I I I " I I ŕ I 0 30 60 90 120 150 180 Time (minutes) Figure 12 Face Temperatures 35- 30- 25- -o- Warm...34• I I I I I t Or)3 0 30 60 90 120 150 :> Time (minutes) Figure 3Z-b. EMG Activity of Pectoralis Major Muscle During Rifle Shooting •" 400- w -.-- Warm...34• 350- (1)o) 300- _m_ Cold (0 o 250-> .- t -. SST S200- S150- 50- -5 0 I =

Interactions of Subsymptomatic Doses of Sarin with Pyridostigmine - Neurochemical, Behavioral, and Physiological Effects

DTIC Science & Technology

2005-03-01

electrocardiogram (ECG) by suturing one of them with 5-0 polyvinyl material to the subcutaneous tissue over the right scapula and the other one at the...bands (Pereira de Souza et al.,2001). Concentrations ofACh, Ch, their deuterated variants, and ACh turnover in brain tissue . Animals were anesthetized...mesencephalon, neocortex, piriform cortex, and striatum. These tissue fragments were homogenized in ice cold 15% IN formic acid, 85% acetone for analysis

Physiological ecology of overwintering in the hatchling painted turtle: multiple-scale variation in response to environmental stress.

PubMed

Costanzo, Jon P; Dinkelacker, Stephen A; Iverson, John B; Lee, Richard E

2004-01-01

We integrated field and laboratory studies in an investigation of water balance, energy use, and mechanisms of cold-hardiness in hatchling painted turtles (Chrysemys picta) indigenous to west-central Nebraska (Chrysemys picta bellii) and northern Indiana (Chrysemys picta marginata) during the winters of 1999-2000 and 2000-2001. We examined 184 nests, 80 of which provided the hatchlings (n=580) and/or samples of soil used in laboratory analyses. Whereas winter 1999-2000 was relatively dry and mild, the following winter was wet and cold; serendipitously, the contrast illuminated a marked plasticity in physiological response to environmental stress. Physiological and cold-hardiness responses of turtles also varied between study locales, largely owing to differences in precipitation and edaphics and the lower prevailing and minimum nest temperatures (to -13.2 degrees C) encountered by Nebraska turtles. In Nebraska, winter mortality occurred within 12.5% (1999-2000) and 42.3% (2000-2001) of the sampled nests; no turtles died in the Indiana nests. Laboratory studies of the mechanisms of cold-hardiness used by hatchling C. picta showed that resistance to inoculative freezing and capacity for freeze tolerance increased as winter approached. However, the level of inoculation resistance strongly depended on the physical characteristics of nest soil, as well as its moisture content, which varied seasonally. Risk of inoculative freezing (and mortality) was greatest in midwinter when nest temperatures were lowest and soil moisture and activity of constituent organic ice nuclei were highest. Water balance in overwintering hatchlings was closely linked to dynamics of precipitation and soil moisture, whereas energy use and the size of the energy reserve available to hatchlings in spring depended on the winter thermal regime. Acute chilling resulted in hyperglycemia and hyperlactemia, which persisted throughout winter; this response may be cryoprotective. Some physiological characteristics and cold-hardiness attributes varied between years, between study sites, among nests at the same site, and among siblings sharing nests. Such variation may reflect adaptive phenotypic plasticity, maternal or paternal influence on an individual's response to environmental challenge, or a combination of these factors. Some evidence suggests that life-history traits, such as clutch size and body size, have been shaped by constraints imposed by the harsh winter environment.

What are the Physiological Mechanisms for Post-Exercise Cold Water Immersion in the Recovery from Prolonged Endurance and Intermittent Exercise?

PubMed

Ihsan, Mohammed; Watson, Greig; Abbiss, Chris R

2016-08-01

Intense training results in numerous physiological perturbations such as muscle damage, hyperthermia, dehydration and glycogen depletion. Insufficient/untimely restoration of these physiological alterations might result in sub-optimal performance during subsequent training sessions, while chronic imbalance between training stress and recovery might lead to overreaching or overtraining syndrome. The use of post-exercise cold water immersion (CWI) is gaining considerable popularity among athletes to minimize fatigue and accelerate post-exercise recovery. CWI, through its primary ability to decrease tissue temperature and blood flow, is purported to facilitate recovery by ameliorating hyperthermia and subsequent alterations to the central nervous system (CNS), reducing cardiovascular strain, removing accumulated muscle metabolic by-products, attenuating exercise-induced muscle damage (EIMD) and improving autonomic nervous system function. The current review aims to provide a comprehensive and detailed examination of the mechanisms underpinning acute and longer term recovery of exercise performance following post-exercise CWI. Understanding the mechanisms will aid practitioners in the application and optimisation of CWI strategies to suit specific recovery needs and consequently improve athletic performance. Much of the literature indicates that the dominant mechanism by which CWI facilitates short term recovery is via ameliorating hyperthermia and consequently CNS mediated fatigue and by reducing cardiovascular strain. In contrast, there is limited evidence to support that CWI might improve acute recovery by facilitating the removal of muscle metabolites. CWI has been shown to augment parasympathetic reactivation following exercise. While CWI-mediated parasympathetic reactivation seems detrimental to high-intensity exercise performance when performed shortly after, it has been shown to be associated with improved longer term physiological recovery and day to day training performances. The efficacy of CWI for attenuating the secondary effects of EIMD seems dependent on the mode of exercise utilised. For instance, CWI application seems to demonstrate limited recovery benefits when EIMD was induced by single-joint eccentrically biased contractions. In contrast, CWI seems more effective in ameliorating effects of EIMD induced by whole body prolonged endurance/intermittent based exercise modalities.

Radioprotection in depressed metabolic states: The physiology of helium-cold hypothermia

NASA Technical Reports Server (NTRS)

Musacchia, X. J.

1973-01-01

The use of hypothermia as a means of radiation protection was studied on a variety of mammals exposed to 80% helium-20% oxygen atmospheres at low ambient temperatures. Results show that the LD for normothermic animals significantly increased compared with hypothermic animals; similar results were obtained for hibernating mammalians. Pre-exposure of animals to cold temperatures increased their ability to withstand radiation levels close to LD sub 50.

Survival in Cold Waters: Staying Alive

DTIC Science & Technology

2003-01-01

19 CHAPTER 2: HOW CAN WE PROTECT FROM THE FOUR PHYSIOLOGICAL STAGES OF COLD WATER IMMERSION...carry liferafts that can easily be launched and boarded by the entire crew and passengers. (c) The only exception to this should be where it is...water into the system will reduce insulation by 30% 2 (d) the maximum insulation that can be added to a suit to prevent heat loss and still be wearable

The impact of acclimatization on thermophysiological strain for contrasting regional climates

NASA Astrophysics Data System (ADS)

de Freitas, C. R.; Grigorieva, E. A.

2014-12-01

During acclimatization to heat and cold, the body experiences additional thermally induced physiological strain. The first signs show up in the respiratory organs because respiration is a continuous heat exchange process in which the body is in closest contact with the ambient air. There are no behavioral or other adjustments to prevent the ambient air from entering into the body's core area through the respiratory tract. The Acclimatization Thermal Strain Index (ATSI) describes the acclimatization thermal loading (ATL) on respiratory organs until full adaptation is achieved. The aim here is to further assess the ATSI scheme using a range of actual but contrasting bioclimatic conditions. To simulate ATL, scenarios of the consequences of acclimatization due to movement to or from five contrasting climates are used. The results show that adjusting to cold comes with greater physiological strain than adjusting to heat, the biggest impact occurring for a change of location from hot-humid to cold-dry climatic conditions. The approach can be used to assess risks due to increases in short-term thermal variability in weather conditions such as encountered during heat waves and cold snaps. The information could also be useful for assessing the need for public health services and measures that might be used to help mitigate impacts.

The impact of acclimatization on thermophysiological strain for contrasting regional climates.

PubMed

de Freitas, C R; Grigorieva, E A

2014-12-01

During acclimatization to heat and cold, the body experiences additional thermally induced physiological strain. The first signs show up in the respiratory organs because respiration is a continuous heat exchange process in which the body is in closest contact with the ambient air. There are no behavioral or other adjustments to prevent the ambient air from entering into the body's core area through the respiratory tract. The Acclimatization Thermal Strain Index (ATSI) describes the acclimatization thermal loading (ATL) on respiratory organs until full adaptation is achieved. The aim here is to further assess the ATSI scheme using a range of actual but contrasting bioclimatic conditions. To simulate ATL, scenarios of the consequences of acclimatization due to movement to or from five contrasting climates are used. The results show that adjusting to cold comes with greater physiological strain than adjusting to heat, the biggest impact occurring for a change of location from hot-humid to cold-dry climatic conditions. The approach can be used to assess risks due to increases in short-term thermal variability in weather conditions such as encountered during heat waves and cold snaps. The information could also be useful for assessing the need for public health services and measures that might be used to help mitigate impacts.

Analysis of the synoptic winter mortality climatology in five regions of England: Searching for evidence of weather signals.

PubMed

Paschalidou, A K; Kassomenos, P A; McGregor, G R

2017-11-15

Although heat-related mortality has received considerable research attention, the impact of cold weather on public health is less well-developed, probably due to the fact that physiological responses to cold weather can vary substantially among individuals, age groups, diseases etc., depending on a number of behavioral and physiological factors. In the current work we use the classification techniques provided by the COST-733 software to link synoptic circulation patterns with excess cold-related mortality in 5 regions of England. We conclude that, regardless of the classification scheme used, the most hazardous conditions for public health in England are associated with the prevalence of the Easterly type of weather, favoring advection of cold air from continental Europe. It is noteworthy that there has been observed little-to-no regional variation with regards to the classification results among the 5 regions, suggestive of a spatially homogenous response of mortality to the atmospheric patterns identified. In general, the 10 different groupings of days used reveal that excess winter mortality is linked with the lowest daily minimum/maximum temperatures in the area. However it is not uncommon to observe high mortality rates during days with higher, in relative terms, temperatures, when rapidly changing weather results in an increase of mortality. Such a finding confirms the complexity of cold-related mortality and highlights the importance of synoptic climatology in understanding of the phenomenon. Copyright © 2017 Elsevier B.V. All rights reserved.

Behaviour and physiology: the thermal strategy of leatherback turtles.

PubMed

Bostrom, Brian L; Jones, T Todd; Hastings, Mervin; Jones, David R

2010-11-10

Adult leatherback turtles (Dermochelys coriacea) exhibit thermal gradients between their bodies and the environment of ≥8°C in sub-polar waters and ≤4°C in the tropics. There has been no direct evidence for thermoregulation in leatherbacks although modelling and morphological studies have given an indication of how thermoregulation may be achieved. We show for the first time that leatherbacks are indeed capable of thermoregulation from studies on juvenile leatherbacks of 16 and 37 kg. In cold water (< 25°C), flipper stroke frequency increased, heat loss through the plastron, carapace and flippers was minimized, and a positive thermal gradient of up to 2.3°C was maintained between body and environment. In warm water (25 - 31°C), turtles were inactive and heat loss through their plastron, carapace and flippers increased. The thermal gradient was minimized (0.5°C). Using a scaling model, we estimate that a 300 kg adult leatherback is able to maintain a maximum thermal gradient of 18.2°C in cold sub-polar waters. In juvenile leatherbacks, heat gain is controlled behaviourally by increasing activity while heat flux is regulated physiologically, presumably by regulation of blood flow distribution. Hence, harnessing physiology and behaviour allows leatherbacks to keep warm while foraging in cold sub-polar waters and to prevent overheating in a tropical environment.

Behaviour and Physiology: The Thermal Strategy of Leatherback Turtles

PubMed Central

Bostrom, Brian L.; Jones, T. Todd; Hastings, Mervin; Jones, David R.

2010-01-01

Background Adult leatherback turtles (Dermochelys coriacea) exhibit thermal gradients between their bodies and the environment of ≥8°C in sub-polar waters and ≤4°C in the tropics. There has been no direct evidence for thermoregulation in leatherbacks although modelling and morphological studies have given an indication of how thermoregulation may be achieved. Methodology/Principal Findings We show for the first time that leatherbacks are indeed capable of thermoregulation from studies on juvenile leatherbacks of 16 and 37 kg. In cold water (< 25°C), flipper stroke frequency increased, heat loss through the plastron, carapace and flippers was minimized, and a positive thermal gradient of up to 2.3°C was maintained between body and environment. In warm water (25 – 31°C), turtles were inactive and heat loss through their plastron, carapace and flippers increased. The thermal gradient was minimized (0.5°C). Using a scaling model, we estimate that a 300 kg adult leatherback is able to maintain a maximum thermal gradient of 18.2°C in cold sub-polar waters. Conclusions/Significance In juvenile leatherbacks, heat gain is controlled behaviourally by increasing activity while heat flux is regulated physiologically, presumably by regulation of blood flow distribution. Hence, harnessing physiology and behaviour allows leatherbacks to keep warm while foraging in cold sub-polar waters and to prevent overheating in a tropical environment. PMID:21085716

Relationships of self-identified cold tolerance and cold-induced vasodilatation in the finger

NASA Astrophysics Data System (ADS)

Park, Joonhee; Lee, Joo-Young

2016-04-01

This study was conducted to investigate relationships of self-identified cold tolerance and cold-induced vasodilatation (CIVD) in the finger. Nine males and 34 females participated in the following 2 tests: a CIVD test and a self-reported survey. The CIVD test was conducted 30-min cold-water immersion (3.8 ± 0.3 °C) of the middle finger at an air temperature of 27.9 ± 0.1 °C. The self-reported questionnaire consisted of 28 questions about whole and local body cold and heat tolerances. By a cluster analysis on the survey results, the participants were divided into two groups: high self-identified cold tolerance (HSCT, n = 25) and low self-identified cold tolerance (LSCT, n = 18). LSCT had lower self-identified cold tolerance ( P < 0.001), preferred hot thermal stimulation ( P = 0.006), and wore heavier clothing during daily life ( P < 0.001) than HSCT. LSCT had significantly lower maximal finger temperatures ( T max) ( P = 0.040), smaller amplitude ( P = 0.029), and delayed onset time of CIVD ( P = 0.080) when compared to HSCT. Some questions examining the self-identified cold or heat tolerance had relationships with cold tolerance index, T max, and amplitude ( P < 0.1). These results indicate that self-identified cold tolerance classified through a standardized survey could be a good index to predict physiological cold tolerance.

Relationships of self-identified cold tolerance and cold-induced vasodilatation in the finger.

PubMed

Park, Joonhee; Lee, Joo-Young

2016-04-01

This study was conducted to investigate relationships of self-identified cold tolerance and cold-induced vasodilatation (CIVD) in the finger. Nine males and 34 females participated in the following 2 tests: a CIVD test and a self-reported survey. The CIVD test was conducted 30-min cold-water immersion (3.8 ± 0.3 °C) of the middle finger at an air temperature of 27.9 ± 0.1 °C. The self-reported questionnaire consisted of 28 questions about whole and local body cold and heat tolerances. By a cluster analysis on the survey results, the participants were divided into two groups: high self-identified cold tolerance (HSCT, n = 25) and low self-identified cold tolerance (LSCT, n = 18). LSCT had lower self-identified cold tolerance (P < 0.001), preferred hot thermal stimulation (P = 0.006), and wore heavier clothing during daily life (P < 0.001) than HSCT. LSCT had significantly lower maximal finger temperatures (T max) (P = 0.040), smaller amplitude (P = 0.029), and delayed onset time of CIVD (P = 0.080) when compared to HSCT. Some questions examining the self-identified cold or heat tolerance had relationships with cold tolerance index, T max, and amplitude (P < 0.1). These results indicate that self-identified cold tolerance classified through a standardized survey could be a good index to predict physiological cold tolerance.

The impact of experimentally elevated energy expenditure on oxidative stress and lifespan in the short-tailed field vole Microtus agrestis

PubMed Central

Selman, Colin; McLaren, Jane S; Collins, Andrew R; Duthie, Garry G; Speakman, John R

2008-01-01

Life-history theory assumes that animal life histories are a consequence of trade-offs between current activities and future reproductive performance or survival, because resource supply is limited. Empirical evidence for such trade-offs in the wild are common, yet investigations of the underlying mechanisms are rare. Life-history trade-offs may have both physiological and ecological mediated costs. One hypothesized physiological mechanism is that elevated energy metabolism may increase reactive oxygen species production, leading to somatic damage and thus compromising future survival. We investigated the impact of experimentally elevated energy expenditure on oxidative damage, protection and lifespan in short-tailed field voles (Microtus agrestis) maintained in captivity to remove any confounding ecological factor effects. Energy expenditure was elevated via lifelong cold exposure (7±2°C), relative to siblings in the warm (22±2°C). No treatment effect on cumulative mortality risk was observed, with negligible effects on oxidative stress and antioxidant protection. These data suggest that in captive animals physiologically mediated costs on life history do not result from increased energy expenditure and consequent elevations in oxidative stress and reduced survival. PMID:18467297

Exposure to hot and cold environmental conditions does not affect the decision making ability of soccer referees following an intermittent sprint protocol.

PubMed

Taylor, Lee; Fitch, Natalie; Castle, Paul; Watkins, Samuel; Aldous, Jeffrey; Sculthorpe, Nicholas; Midgely, Adrian; Brewer, John; Mauger, Alexis

2014-01-01

Soccer referees enforce the laws of the game and the decisions they make can directly affect match results. Fixtures within European competitions take place in climatic conditions that are often challenging (e.g., Moscow ~ -5°C, Madrid ~30°C). Effects of these temperatures on player performance are well-documented; however, little is known how this environmental stress may impair cognitive performance of soccer referees and if so, whether exercise exasperates this. The present study aims to investigate the effect of cold [COLD; -5°C, 40% relative humidity (RH)], hot (HOT; 30°C, 40% RH) and temperate (CONT; 18°C, 40% RH) conditions on decision making during soccer specific exercise. On separate occasions within each condition, 13 physically active males; either semi-professional referees or semi-professional soccer players completed three 90 min intermittent treadmill protocols that simulated match play, interspersed with 4 computer delivered cognitive tests to measure vigilance and dual task capacity. Core and skin temperature, heart rate, rating of perceived exertion (RPE) and thermal sensation (TS) were recorded throughout the protocol. There was no significant difference between conditions for decision making in either the dual task (interaction effects: FALSE p = 0.46; MISSED p = 0.72; TRACKING p = 0.22) or vigilance assessments (interaction effects: FALSE p = 0.31; HIT p = 0.15; MISSED p = 0.17) despite significant differences in measured physiological variables (skin temperature: HOT vs. CONT 95% CI = 2.6 to 3.9, p < 0.001; HOT vs. COLD 95% CI = 6.6 to 9.0, p < 0.001; CONT vs. COLD 95% CI = 3.4 to 5.7, p < 0.01). It is hypothesized that the lack of difference observed in decision making ability between conditions was due to the exercise protocol used, as it may not have elicited an appropriate and valid soccer specific internal load to alter cognitive functioning.

The effect of food temperature on postprandial metabolism in albatrosses.

PubMed

Battam, H; Chappell, M A; Buttemer, W A

2008-04-01

Heat generated by the specific dynamic action (SDA) associated with feeding is known to substitute for the thermoregulatory costs of cold-exposed endotherms; however, the effectiveness of this depends on food temperature. When food is cooler than core body temperature, it is warmed by body heat and, consequently, imposes a thermoregulatory challenge to the animal. The degree to which this cost might be ;paid' by SDA depends on the relative timing of food heating and the SDA response. We investigated this phenomenon in two genera of endotherms, Diomedea and Thalassarche albatrosses, by measuring postprandial metabolic rate following ingestion of food at body temperature (40 degrees C) and cooler (0 and 20 degrees C). This permitted us to estimate potential contributions to food warming by SDA-derived heat, and to observe the effect of cold food on metabolic rate. For meal sizes that were approximately 20% of body mass, SDA was 4.22+/-0.37% of assimilated food energy, and potentially contributed 17.9+/-1.0% and 13.2+/-2.2% of the required heating energy of food at 0 degrees C for Diomedea and Thalassarche albatrosses, respectively, and proportionately greater quantities at higher food temperatures. Cold food increased the rate at which postprandial metabolic rate increased to 3.2-4.5 times that associated with food ingested at body temperature. We also found that albatrosses generated heat in excess by more than 50% of the estimated thermostatic heating demand of cold food, a probable consequence of time delays in physiological responses to afferent signals.

The overwintering physiology of the emerald ash borer, Agrilus planipennis fairmaire (coleoptera: buprestidae).

PubMed

Crosthwaite, Jill C; Sobek, Stephanie; Lyons, D Barry; Bernards, Mark A; Sinclair, Brent J

2011-01-01

Ability to survive cold is an important factor in determining northern range limits of insects. The emerald ash borer (Agrilus planipennis) is an invasive beetle introduced from Asia that is causing extensive damage to ash trees in North America, but little is known about its cold tolerance. Herein, the cold tolerance strategy and mechanisms involved in the cold tolerance of the emerald ash borer were investigated, and seasonal changes in these mechanisms monitored. The majority of emerald ash borers survive winter as freeze-intolerant prepupae. In winter, A. planipennis prepupae have low supercooling points (approximately -30°C), which they achieve by accumulating high concentrations of glycerol (approximately 4M) in their body fluids and by the synthesis of antifreeze agents. Cuticular waxes reduce inoculation from external ice. This is the first comprehensive study of seasonal changes in cold tolerance in a buprestid beetle. 2010 Elsevier Ltd. All rights reserved.

Thermo-Physiological Responses of Sailors in a Disabled Submarine with Interior Cabin Temperature and Humidity Slowly Rising as Predicted by Computer Simulation Techniques

DTIC Science & Technology

2013-09-01

define CSTR .5 // 1/°C #define SKBFN 6.3 // liters/(h m^2) #define Skbfmax 90. // conservative could be higher for fit person 36 #define...WarmC=0; if (Tsk<TTSK) Colds=TTSK-Tsk; if (Tc>TTCR) WarmC=Tc-TTCR; Skbf=(SKBFN+CDIL*WarmC)/(1+ CSTR *Colds); // Liters/(h m^2) if (Skbf

The Physiological Basis for Various Constituents in Survival Rations. Part 4. An Integrative Study of the All-Purpose Survival Ration for Temperate, Cold, and Hot Weather

DTIC Science & Technology

1957-12-01

on healthy young men during successive two-week periods of adequate, restricted, and recovery diets . Starvation and an adequate 3000-Calorie diet ...Regardless of temperature, work load, or water intake, one and the same regimen ranked next to the adequate 3000-Calorie diet in minimizing...plus minerals; no ketogenic effect. 4. Limitation of water; decrease of calories; marked deviation in protein/carbohydrate/fat ratios; marked deviation

Comparative analysis of the response and gene regulation in cold resistant and susceptible tea plants

PubMed Central

Pan, Cheng; Wang, Yiwei; Kong, Lei; Jiang, Huiguang; Xu, Yiqun; Wang, Wenzhi; Pan, Yuting; Li, Yeyun; Jiang, Changjun

2017-01-01

Cold environment is the main constraint for tea plants (Camellia sinensis) distribution and tea farming. We identified two tea cultivars, called var. sinensis cv. Shuchazao (SCZ) with a high cold-tolerance and var. assamica cv. Yinghong9 (YH9) with low cold-tolerance. To better understand the response mechanism of tea plants under cold stress for improving breeding, we compared physiological and biochemical responses, and associated genes expression in response to 7-day and 14-day cold acclimation, followed by 7-day de-acclimation in these two tea cultivars. We found that the low EL50, low Fv/Fm, and high sucrose and raffinose accumulation are responsible for higher cold tolerance in SCZ comparing with YH9. We then measured the expression of 14 key homologous genes, known as involved in these responses in other plants, for each stages of treatment in both cultivars using RT-qPCR. Our results suggested that the increased expression of CsCBF1 and CsDHNs coupling with the accumulation of sucrose play key roles in conferring higher cold resistance in SCZ. Our findings have revealed key genes regulation responsible for cold resistance, which help to understand the cold-resistant mechanisms and guide breeding in tea plants. PMID:29211766

Comparative analysis of the response and gene regulation in cold resistant and susceptible tea plants.

PubMed

Ban, Qiuyan; Wang, Xuewen; Pan, Cheng; Wang, Yiwei; Kong, Lei; Jiang, Huiguang; Xu, Yiqun; Wang, Wenzhi; Pan, Yuting; Li, Yeyun; Jiang, Changjun

2017-01-01

Cold environment is the main constraint for tea plants (Camellia sinensis) distribution and tea farming. We identified two tea cultivars, called var. sinensis cv. Shuchazao (SCZ) with a high cold-tolerance and var. assamica cv. Yinghong9 (YH9) with low cold-tolerance. To better understand the response mechanism of tea plants under cold stress for improving breeding, we compared physiological and biochemical responses, and associated genes expression in response to 7-day and 14-day cold acclimation, followed by 7-day de-acclimation in these two tea cultivars. We found that the low EL50, low Fv/Fm, and high sucrose and raffinose accumulation are responsible for higher cold tolerance in SCZ comparing with YH9. We then measured the expression of 14 key homologous genes, known as involved in these responses in other plants, for each stages of treatment in both cultivars using RT-qPCR. Our results suggested that the increased expression of CsCBF1 and CsDHNs coupling with the accumulation of sucrose play key roles in conferring higher cold resistance in SCZ. Our findings have revealed key genes regulation responsible for cold resistance, which help to understand the cold-resistant mechanisms and guide breeding in tea plants.

Peripheral kappa-opioid agonist, ICI 204448, evokes hypothermia in cold-exposed rats.

PubMed

Rawls, Scott M; Ding, Zhe; Gray, Alex M; Cowan, Alan

2005-05-01

ICI 204448, a selective kappa-opioid agonist with limited CNS access, can be used to discriminate central and peripheral opioid actions on physiological systems such as pain and thermoregulation. Therefore, we investigated the effect of ICI 204448 (2.5, 5, and 10 mg/kg, s.c.) on male Sprague-Dawley rats exposed to ambient temperatures of 5, 20, or 32 degrees C. ICI 204448 did not alter the body temperature of rats maintained at 20 or 32 degrees C. However, 5 and 10 mg/kg of ICI 204448 evoked significant hypothermia in rats exposed to 5 degrees C. The i.c.v. administration of nor-BNI, a kappa-opioid antagonist, did not affect the hypothermia produced by the systemic injection of ICI 204448. Thus, an involvement of brain kappa-opioid receptors in ICI 204448-evoked hypothermia is unlikely. The present data demonstrate for the first time that ICI 204448 produces hypothermia in cold-exposed rats and suggest that the role of peripheral kappa-opioid receptors in thermoregulation becomes more significant at cold ambient temperatures. Copyright (c) 2005 S. Karger AG, Basel.

Effects of ethrel, 1-MCP and modified atmosphere packaging on the quality of 'Wonderful' pomegranates during cold storage.

PubMed

Valdenegro, Mónika; Huidobro, Camila; Monsalve, Liliam; Bernales, Maricarmen; Fuentes, Lida; Simpson, Ricardo

2018-03-24

Pomegranate (Punica granatum) is a non-climacteric fruit susceptible to chilling injury (CI) at temperatures below 5 °C. To understand the influences of ethylene and modified atmosphere on CI physiological disorders of pomegranate, exogenous ethrel (0.5, 1 and 1.5 µg L -1 ) treatments, 1-methylcyclopropene (1-MCP) (1 µL L -1 ) exposure, packaging in a modified atmosphere (MAP) (XTend™ bags; StePac, São Paulo, Brazil), a MAP/1-MCP combination, and packaging in macro-perforated bags (MPB) were applied. The treated fruits were cold stored (2 ± 1 °C; 85% relative humidity) and sampled during 120 + 3 days at 20 °C. During cold storage, CI symptoms started at 20 days in MPB and at 60 days for all exogenous ethylene treatments, and were delayed to 120 days in MAP, 1-MCP and MAP/1-MCP treatments. MPB and ethylene treatments induced significant electrolyte leakage, oxidative damage, lipid peroxidation, ethylene and CO 2 production, and 1-aminocyclopropane-1-carboxylic acid oxidase activity, without any change in total soluble solids, titratable acidity or skin and aril colours. Conversely, MAP by itself, or in combination with 1-MCP application, effectively delayed CI symptoms. During long-term cold storage of this non-climacteric fruit, ethrel application induced endogenous ethylene biosynthesis, accelerating the appearance of CI symptoms in contrast to the observations made for MAP and 1-MCP treatments. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Activation state of the hyperpolarization-activated current modulates temperature-sensitivity of firing in locus coeruleus neurons from bullfrogs.

PubMed

Santin, Joseph M; Hartzler, Lynn K

2015-06-15

Locus coeruleus neurons of anuran amphibians contribute to breathing control and have spontaneous firing frequencies that, paradoxically, increase with cooling. We previously showed that cooling inhibits a depolarizing membrane current, the hyperpolarization-activated current (I h) in locus coeruleus neurons from bullfrogs, Lithobates catesbeianus (Santin JM, Watters KC, Putnam RW, Hartzler LK. Am J Physiol Regul Integr Comp Physiol 305: R1451-R1464, 2013). This suggests an unlikely role for I h in generating cold activation, but led us to hypothesize that inhibition of I h by cooling functions as a physiological brake to limit the cold-activated response. Using whole cell electrophysiology in brain slices, we employed 2 mM Cs(+) (an I h antagonist) to isolate the role of I h in spontaneous firing and cold activation in neurons recorded with either control or I h agonist (cyclic AMP)-containing artificial intracellular fluid. I h did not contribute to the membrane potential (V m) and spontaneous firing at 20°C. Although voltage-clamp analysis confirmed that cooling inhibits I h, its lack of involvement in setting baseline firing and V m precluded its ability to regulate cold activation as hypothesized. In contrast, neurons dialyzed with cAMP exhibited greater baseline firing frequencies at 20°C due to I h activation. Our hypothesis was supported when the starting level of I h was enhanced by elevating cAMP because cold activation was converted to more ordinary cold inhibition. These findings indicate that situations leading to enhancement of I h facilitate firing at 20°C, yet the hyperpolarization associated with inhibiting a depolarizing cation current by cooling blunts the net V m response to cooling to oppose normal cold-depolarizing factors. This suggests that the influence of I h activation state on neuronal firing varies in the poikilothermic neuronal environment. Copyright © 2015 the American Physiological Society.

To cool, but not too cool: that is the question--immersion cooling for hyperthermia.

PubMed

Taylor, Nigel A S; Caldwell, Joanne N; Van den Heuvel, Anne M J; Patterson, Mark J

2008-11-01

Patient cooling time can impact upon the prognosis of heat illness. Although ice-cold-water immersion will rapidly extract heat, access to ice or cold water may be limited in hot climates. Indeed, some have concerns regarding the sudden cold-water immersion of hyperthermic individuals, whereas others believe that cutaneous vasoconstriction may reduce convective heat transfer from the core. It was hypothesized that warmer immersion temperatures, which induce less powerful vasoconstriction, may still facilitate rapid cooling in hyperthermic individuals. Eight males participated in three trials and were heated to an esophageal temperature of 39.5 degrees C by exercising in the heat (36 degrees C, 50% relative humidity) while wearing a water-perfusion garment (40 degrees C). Subjects were cooled using each of the following methods: air (20-22 degrees C), cold-water immersion (14 degrees C), and temperate-water immersion (26 degrees C). The time to reach an esophageal temperature of 37.5 degrees C averaged 22.81 min (air), 2.16 min (cold), and 2.91 min (temperate). Whereas each of the between-trial comparisons was statistically significant (P < 0.05), cooling in temperate water took only marginally longer than that in cold water, and one cannot imagine that the 45-s cooling time difference would have any meaningful physiological or clinical implications. It is assumed that this rapid heat loss was due to a less powerful peripheral vasoconstrictor response, with central heat being more rapidly transported to the skin surface for dissipation. Although the core-to-water thermal gradient was much smaller with temperate-water cooling, greater skin and deeper tissue blood flows would support a superior convective heat delivery. Thus, a sustained physiological mechanism (blood flow) appears to have countered a less powerful thermal gradient, resulting in clinically insignificant differences in heat extraction between the cold and temperate cooling trials.

Evolution of nonspectral rhodopsin function at high altitudes.

PubMed

Castiglione, Gianni M; Hauser, Frances E; Liao, Brian S; Lujan, Nathan K; Van Nynatten, Alexander; Morrow, James M; Schott, Ryan K; Bhattacharyya, Nihar; Dungan, Sarah Z; Chang, Belinda S W

2017-07-11

High-altitude environments present a range of biochemical and physiological challenges for organisms through decreases in oxygen, pressure, and temperature relative to lowland habitats. Protein-level adaptations to hypoxic high-altitude conditions have been identified in multiple terrestrial endotherms; however, comparable adaptations in aquatic ectotherms, such as fishes, have not been as extensively characterized. In enzyme proteins, cold adaptation is attained through functional trade-offs between stability and activity, often mediated by substitutions outside the active site. Little is known whether signaling proteins [e.g., G protein-coupled receptors (GPCRs)] exhibit natural variation in response to cold temperatures. Rhodopsin (RH1), the temperature-sensitive visual pigment mediating dim-light vision, offers an opportunity to enhance our understanding of thermal adaptation in a model GPCR. Here, we investigate the evolution of rhodopsin function in an Andean mountain catfish system spanning a range of elevations. Using molecular evolutionary analyses and site-directed mutagenesis experiments, we provide evidence for cold adaptation in RH1. We find that unique amino acid substitutions occur at sites under positive selection in high-altitude catfishes, located at opposite ends of the RH1 intramolecular hydrogen-bonding network. Natural high-altitude variants introduced into these sites via mutagenesis have limited effects on spectral tuning, yet decrease the stability of dark-state and light-activated rhodopsin, accelerating the decay of ligand-bound forms. As found in cold-adapted enzymes, this phenotype likely compensates for a cold-induced decrease in kinetic rates-properties of rhodopsin that mediate rod sensitivity and visual performance. Our results support a role for natural variation in enhancing the performance of GPCRs in response to cold temperatures.

Expanding NevCAN capabilities: monitoring cold air drainage flow along a narrow wash within a Montane to PJ ecotone

NASA Astrophysics Data System (ADS)

Bird, B. M.; Devitt, D.

2012-12-01

Cold air drainage flows are a naturally occurring physical process of mountain systems. Plant communities that exist in cold air drainage basins respond to these localized cold air trends, and have been shown to be decoupled from larger global climate weather systems. The assumption that air temperature decreases with altitude is violated within these systems and climate model results based on this assumption would ultimately be inaccurate. In arid regions, high radiation loads lead to significant long wave radiation being emitted from the ground later in the day. As incoming radiation ceases, the surface very quickly loses energy through radiative processes, leading to surface inversions and enhanced cold air drainage opportunities. This study is being conducted in the Mojave desert on Sheep Mountain located between sites 3 and 4 of the NSF EPSCoR network. Monitoring of cold air drainage was initiated in September of 2011within a narrow ravine located between the 2164 and 2350 meter elevation. We have installed 25 towers (5 towers per location situated at the central low point in a ravine and at equal distances up the sides of the ravine on both the N and S facing slopes) to assess air temperatures from 0.1 meters to a height of 3 meters at 25m intervals. Our goal is to better understand the connection between cold air movement and plant physiological response. The species monitored in this study include: Pinus ponderosa (common name: Ponderosa Pine), Pinus pinyon (Pinyon Pine), Juniperus osteosperma (Utah juniper), Cercocarpus intricatus (Mountain Mahogany) and Symphoricarpos (snowberry). Hourly air temperature measurements within the wash are being captured from 100 ibuttons placed within PVC solar radiation shields. We are also developing a modeling approach to assess the three dimensional movement of cold air over time by incorporating wind vectors captured from 5 2D sonic anemometers. Wind velocities will be paired with air temperatures to better understand the thermal dynamics of cold air drainage. Granier probes were installed in the five test species to monitor transpirational flow relative to cold air movement. Mid day soil - plant - water measurements are also being taken on a monthly basis during the growing season at all locations. Measurements include: leaf xylem water potential, stomata conductance, chlorophyll index readings, canopy minus ambient temperatures and surface soil moisture contents. To date the monitoring system has revealed cold air drainage occurring during periods of every month. We will report the physiological response of the five plant species, with emphasis on assessing the linkages with cold air movement.

Physiological responses and manual performance in humans following repeated exposure to severe cold at night.

PubMed

Ozaki, H; Nagai, Y; Tochihara, Y

2001-04-01

We evaluated human physiological responses and the performance of manual tasks during exposure to severe cold (-25 degrees C) at night (0300-0500 hours) and in the afternoon (1500-1700 hours). Thirteen male students wearing standard cold protective clothing occupied a severely cold room (-25 degrees C) for 20 min, and were then transferred to a cool room (10 degrees C) for 20 min. This pattern of exposure was repeated three times, for a total time of exposure to extreme cold of 60 min. The experiments were started either at 1500 hours or 0300 hours and measurements of rectal temperature, skin temperature, blood pressure, performance in a counting task, hand tremor, and subjective responses were made in each condition. At the end of the experiment at night the mean decrease in rectal temperature [0.68 (SEM 0.04) degree C] was significantly greater than that at the end of the experiment in the afternoon [0.55 (SEM 0.08) degree C, P < 0.01]. After the second cold exposure at night the mean increase in diastolic blood pressure [90 (SEM 2.0) mmHg] was significantly greater than that at the end of the second cold exposure in the afternoon [82 (SEM 2.8) mmHg, P < 0.01]. At the end of the second cold exposure at night, mean finger skin temperature [11.8 (SEM 0.8) degrees C] was significantly higher than that at the comparable time in the afternoon [9.0 (SEM 0.7) degrees C, P < 0.01]. Similarly for the toe, mean skin temperature at the start of the second cold exposure at night [25.6 (SEM 1.5) degrees C] was significantly higher than in the afternoon [20.1 (SEM 0.8) degrees C, P < 0.01]. The increased skin temperatures in the periphery resulted in increased heat loss. Since peripheral skin temperatures were highest at night, the subjects noted diminished sensations of thermal cold and pain at that time. Manual dexterity at the end of the first cold exposure at night [mean 83.7 (SEM 3.6) times.min-1] had decreased significantly more than at the end of the first cold exposure in the afternoon [mean 89.4 (SEM 3.5) times.min-1, P < 0.01]. These findings of a lowered rectal temperature and diminished manual dexterity suggest that there is an increased risk of both hypothermia and accidents for those who work at night.

Glycine increases cold tolerance in rice via the regulation of N uptake, physiological characteristics, and photosynthesis.

PubMed

Xiaochuang, Cao; Chu, Zhong; Lianfeng, Zhu; Junhua, Zhang; Hussain, Sajid; Lianghuan, Wu; Qianyu, Jin

2017-03-01

To investigate the response of rice growth and photosynthesis to different nitrogen (N) sources under cold stress, hydroponic cultivation of rice was done in greenhouse, with glycine, ammonium, and nitrate as the sole N sources. The results demonstrate that exposure to low temperature reduced the rice biomass and leaf chlorophyll content, but their values in the glycine-treated plants were significantly higher than in the ammonium- and nitrate-treated plants. This might be attributed to the higher N uptake rate and root area and activity in the glycine-treated plants. The glycine-treated plants also maintained high contents of soluble proteins, soluble sugars, and proline as well as enhanced antioxidant enzyme activities to protect themselves against chilling injury. Under cold stress, reduced stomatal conductance (g s ) and effective quantum efficiency of PSII (Φ PSII ) significantly inhibited the leaf photosynthesis; however, glycine treatment alleviated these effects compared to the ammonium and nitrate treatments. The high non-photochemical quenching (qN) and excess energy dissipative energy (E x ) in the glycine-treated plants were beneficial for the release of extra energy, thereby, strengthening their photochemical efficiency. We, therefore, conclude that the strengthened cold tolerance of glycine-treated rice plants was closely associated with the higher accumulation of dry matter and photosynthesis through the up-regulation of N-uptake, and increase in the content of osmoprotectants, activities of the antioxidant defense enzymes, and photochemical efficiency. The results of the present study provide new ideas for improving the plant tolerance to extreme temperatures by nutrient resource management in the cold regions. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Skin conditions in figure skaters, ice-hockey players and speed skaters: part II - cold-induced, infectious and inflammatory dermatoses.

PubMed

Tlougan, Brook E; Mancini, Anthony J; Mandell, Jenny A; Cohen, David E; Sanchez, Miguel R

2011-11-01

Participation in ice-skating sports, particularly figure skating, ice hockey and speed skating, has increased in recent years. Competitive athletes in these sports experience a range of dermatological injuries related to mechanical factors: exposure to cold temperatures, infectious agents and inflammation. Part I of this two part review discussed the mechanical dermatoses affecting ice-skating athletes that result from friction, pressure, and chronic irritation related to athletic equipment and contact with surfaces. Here, in Part II, we review the cold-induced, infectious and inflammatory skin conditions observed in ice-skating athletes. Cold-induced dermatoses experienced by ice-skating athletes result from specific physiological effects of cold exposure on the skin. These conditions include physiological livedo reticularis, chilblains (pernio), Raynaud phenomenon, cold panniculitis, frostnip and frostbite. Frostbite, that is the literal freezing of tissue, occurs with specific symptoms that progress in a stepwise fashion, starting with frostnip. Treatment involves gradual forms of rewarming and the use of friction massages and pain medications as needed. Calcium channel blockers, including nifedipine, are the mainstay of pharmacological therapy for the major nonfreezing cold-induced dermatoses including chilblains and Raynaud phenomenon. Raynaud phenomenon, a vasculopathy involving recurrent vasospasm of the fingers and toes in response to cold, is especially common in figure skaters. Protective clothing and insulation, avoidance of smoking and vasoconstrictive medications, maintaining a dry environment around the skin, cold avoidance when possible as well as certain physical manoeuvres that promote vasodilation are useful preventative measures. Infectious conditions most often seen in ice-skating athletes include tinea pedis, onychomycosis, pitted keratolysis, warts and folliculitis. Awareness, prompt treatment and the use of preventative measures are particularly important in managing such dermatoses that are easily spread from person to person in training facilities. The use of well ventilated footgear and synthetic substances to keep feet dry, as well as wearing sandals in shared facilities and maintaining good personal hygiene are very helpful in preventing transmission. Inflammatory conditions that may be seen in ice-skating athletes include allergic contact dermatitis, palmoplantar eccrine hidradenitis, exercise-induced purpuric eruptions and urticaria. Several materials commonly used in ice hockey and figure skating cause contact dermatitis. Identification of the allergen is essential and patch testing may be required. Exercise-induced purpuric eruptions often occur after exercise, are rarely indicative of a chronic venous disorder or other haematological abnormality and the lesions typically resolve spontaneously. The subtypes of urticaria most commonly seen in athletes are acute forms induced by physical stimuli, such as exercise, temperature, sunlight, water or particular levels of external pressure. Cholinergic urticaria is the most common type of physical urticaria seen in athletes aged 30 years and under. Occasionally, skaters may develop eating disorders and other related behaviours some of which have skin manifestations that are discussed herein. We hope that this comprehensive review will aid sports medicine practitioners, dermatologists and other physicians in the diagnosis and treatment of these dermatoses.

Influence of temperature on the corticosterone stress-response: an experiment in the Children's python (Antaresia childreni).

PubMed

Dupoué, Andréaz; Brischoux, François; Lourdais, Olivier; Angelier, Frédéric

2013-11-01

To cope with environmental challenges, organisms have to adjust their behaviours and their physiology to the environmental conditions they face (i.e. allostasis). In vertebrates, such adjustments are often mediated through the secretion of glucocorticoids (GCs) that are well-known to activate and/or inhibit specific physiological and behavioural traits. In ectothermic species, most processes are temperature-dependent and according to previous studies, low external temperatures should be associated with low GC concentrations (both baseline and stress-induced concentrations). In this study, we experimentally tested this hypothesis by investigating the short term influence of temperature on the GC stress response in a squamate reptile, the Children's python (Antaresia childreni). Snakes were maintained in contrasting conditions (warm and cold groups), and their corticosterone (CORT) stress response was measured (baseline and stress-induced CORT concentrations), within 48h of treatment. Contrary to our prediction, baseline and stress-induced CORT concentrations were higher in the cold versus the warm treatment. In addition, we found a strong negative relationship between CORT concentrations (baseline and stress-induced) and temperature within the cold treatment. Although it remains unclear how cold temperatures can mechanistically result in increased CORT concentrations, we suggest that, at suboptimal temperature, high CORT concentrations may help the organism to maintain an alert state. Copyright © 2013 Elsevier Inc. All rights reserved.

Physiological indicators of nitrogen response in short-rotation sycamore plantations. [Platanus occidentalis L

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tschaplinski, T.J.; Norby, R.J.

1989-04-01

American sycamore (Platanus occidentalis L.) seedlings were grown in the field under urea-nitrogen fertilization regimes to identify physiological variables that characterize the growth responses. Treatments included trees fertilized at the beginning of the growing season with 450 kg N/ha, trees fertilized periodically (three times during the growing season) at 37.5 kg N/ha, and unfertilized controls. Above ground biomass accumulation in the heaviest nitrogen treatment was three times that of the controls, and nearly as much growth occurred when less nitrogen was added periodically. Photosynthesis, chlorophyll concentrations, and growth increased rapidly after a midseason application of a small amount of nitrogen,more » but not to a late-season application. There was no evidence that fertilization extended the physiologically active season or increased susceptibility to drought or cold. Sycamore leaves accumulated sucrose and mannose in response to water and cold stress in all treatments. Photosynthetic pigment concentrations, net photosynthetic rate, and leaf nitrate reductase activity were sensitive indicators of nitrogen fertilization, but foliar concentrations of nitrate, total nitrogen, soluble carbohydrate and soluble protein were not.« less

The phytotronist and the phenotype: plant physiology, Big Science, and a Cold War biology of the whole plant.

PubMed

Munns, David P D

2015-04-01

This paper describes how, from the early twentieth century, and especially in the early Cold War era, the plant physiologists considered their discipline ideally suited among all the plant sciences to study and explain biological functions and processes, and ranked their discipline among the dominant forms of the biological sciences. At their apex in the late-1960s, the plant physiologists laid claim to having discovered nothing less than the "basic laws of physiology." This paper unwraps that claim, showing that it emerged from the construction of monumental big science laboratories known as phytotrons that gave control over the growing environment. Control meant that plant physiologists claimed to be able to produce a standard phenotype valid for experimental biology. Invoking the standards of the physical sciences, the plant physiologists heralded basic biological science from the phytotronic produced phenotype. In the context of the Cold War era, the ability to pursue basic science represented the highest pinnacle of standing within the scientific community. More broadly, I suggest that by recovering the history of an underappreciated discipline, plant physiology, and by establishing the centrality of the story of the plant sciences in the history of biology can historians understand the massive changes wrought to biology by the conceptual emergence of the molecular understanding of life, the dominance of the discipline of molecular biology, and the rise of biotechnology in the 1980s. Copyright © 2015 Elsevier Ltd. All rights reserved.

Normothermic perfusion: a new paradigm for organ preservation.

PubMed

Brockmann, Jens; Reddy, Srikanth; Coussios, Constantin; Pigott, David; Guirriero, Dino; Hughes, David; Morovat, Alireza; Roy, Debabrata; Winter, Lucy; Friend, Peter J

2009-07-01

Transplantation of organs retrieved after cardiac arrest could increase the donor organ supply. However, the combination of warm ischemia and cold preservation is highly detrimental to the reperfused organ. Our objective was to maintain physiological temperature and organ function during preservation and thereby alleviate this injury and allow successful transplantation. We have developed a liver perfusion device that maintains physiological temperature with provision of oxygen and nutrition. Reperfusion experiments suggested that this allows recovery of ischemic damage. In a pig liver transplant model, we compared the outcome following either conventional cold preservation or warm preservation. Preservation periods of 5 and 20 hours and durations of warm ischemia of 40 and 60 minutes were tested. After 20 hours preservation without warm ischemia, post-transplant survival was improved (27%-86%, P = 0.026), with corresponding differences in transaminase levels and histological analysis. With the addition of 40 minutes warm ischemia, the differences were even more marked (cold vs. warm groups 0% vs. 83%, P = 0.001). However, with 60 minutes warm ischemia and 20 hours preservation, there were no survivors. Analysis of hemodynamic and liver function data during perfusion showed several factors to be predictive of posttransplant survival, including bile production, base excess, portal vein flow, and hepatocellular enzymes. Organ preservation by warm perfusion, maintaining physiological pressure and flow parameters, has enabled prolonged preservation and successful transplantation of both normal livers and those with substantial ischemic damage. This technique has the potential to address the shortage of organs for transplantation.

The Behavior-Physiology Nexus: Behavioral and Physiological Compensation Are Relied on to Different Extents between Seasons.

PubMed

Basson, Christine H; Clusella-Trullas, Susana

2015-01-01

Environmental variability occurring at different timescales can significantly reduce performance, resulting in evolutionary fitness costs. Shifts in thermoregulatory behavior, metabolism, and water loss via phenotypic plasticity can compensate for thermal variation, but the relative contribution of each mechanism and how they may influence each other are largely unknown. Here, we take an ecologically relevant experimental approach to dissect these potential responses at two temporal scales: weather transients and seasons. Using acclimation to cold, average, or warm conditions in summer and winter, we measure the direction and magnitude of plasticity of resting metabolic rate (RMR), water loss rate (WLR), and preferred body temperature (Tpref) in the lizard Cordylus oelofseni within and between seasons. In summer, lizards selected lower Tpref when acclimated to warm versus cold but had no plasticity of either RMR or WLR. By contrast, winter lizards showed partial compensation of RMR but no behavioral compensation. Between seasons, both behavioral and physiological shifts took place. By integrating ecological reality into laboratory assays, we demonstrate that behavioral and physiological responses of C. oelofseni can be contrasting, depending on the timescale investigated. Incorporating ecologically relevant scenarios and the plasticity of multiple traits is thus essential when attempting to forecast extinction risk to climate change.

Physiological Equivalent Temperature Index and mortality in Tabriz (The northwest of Iran).

PubMed

Sharafkhani, Rahim; Khanjani, Narges; Bakhtiari, Bahram; Jahani, Yunes; Sadegh Tabrizi, Jafar

2018-01-01

There are few epidemiological studies about climate change and the effect of temperature variation on health using human thermal indices such as the Physiological Equivalent Temperature (PET) Index in Iran. This study was conducted in Tabriz, the northwest of Iran and Distributed Lag Non-linear Models (DLNM) combined with quasi-Poisson regression models were used to assess the impacts of PET on mortality by using the DLNM Package in R Software. The effect of air pollutants, time trend, day of the week and holidays were controlled as confounders. There was a significant relation between high (30°C, 27°C) and low (-0.8°C, -9.2°C and -14.2°C) PET and total (non-accidental) mortality; and a significant increase in respiratory and cardiovascular deaths in high PET values. Heat stress increased Cumulative Relative Risk (CRR) for total (non-accidental), respiratory and cardiovascular mortality significantly (CRR Non Accidental Death, PET=30°C, lag 0-30 =1.67, 95%CI: 1.31-2.13; CRR Respiratory Death, PET=30°C, lag 0-13 =1.88, 95%CI: 1.30-2.72; CRR Cardiovascular Death, PET=30°C, lag0-30 =1.67 95%CI: 1.16-2.40). Heat stress increases the risk of total (non-accidental), respiratory mortality, but cold stress decreases the risk of total (non-accidental) mortality in Tabriz which is one of the cold cities of Iran. Copyright © 2017 Elsevier Ltd. All rights reserved.

Global transcriptional profiling of a cold-tolerant rice variety under moderate cold stress reveals different cold stress response mechanisms.

PubMed

Zhao, Junliang; Zhang, Shaohong; Yang, Tifeng; Zeng, Zichong; Huang, Zhanghui; Liu, Qing; Wang, Xiaofei; Leach, Jan; Leung, Hei; Liu, Bin

2015-07-01

Gene expression profiling under severe cold stress (4°C) has been conducted in plants including rice. However, rice seedlings are frequently exposed to milder cold stresses under natural environments. To understand the responses of rice to milder cold stress, a moderately low temperature (8°C) was used for cold treatment prior to genome-wide profiling of gene expression in a cold-tolerant japonica variety, Lijiangxintuanheigu (LTH). A total of 5557 differentially expressed genes (DEGs) were found at four time points during moderate cold stress. Both the DEGs and differentially expressed transcription factor genes were clustered into two groups based on their expression, suggesting a two-phase response to cold stress and a determinative role of transcription factors in the regulation of stress response. The induction of OsDREB2A under cold stress is reported for the first time in this study. Among the anti-oxidant enzyme genes, glutathione peroxidase (GPX) and glutathione S-transferase (GST) were upregulated, suggesting that the glutathione system may serve as the main reactive oxygen species (ROS) scavenger in LTH. Changes in expression of genes in signal transduction pathways for auxin, abscisic acid (ABA) and salicylic acid (SA) imply their involvement in cold stress responses. The induction of ABA response genes and detection of enriched cis-elements in DEGs suggest that ABA signaling pathway plays a dominant role in the cold stress response. Our results suggest that rice responses to cold stress vary with the specific temperature imposed and the rice genotype. © 2014 Scandinavian Plant Physiology Society.

The influence of cold on energy expenditure at rest and during exercise in person in the North.

PubMed

Grishin, O V; Ustuzaninova, N V

2007-01-01

In the majority of research on human adaptation in the North signs of hypoxia were found. In physiology studies of animals it is established that adaptive changes to cold and hypoxia have much in common, for example, the decrease of spent energy (hypometabolism). This phenomenon has been studied much less in humans than in animals. The first study was that of A. Hemingway and L. Birzis which showed that under the influence of air temperature of -3 degrees C on natives of Kalahari deserts the average body temperature and level of metabolism decrease. The reduction of lung ventilation and decrease of heat loss in humans was interpreted as the result of cold. However, it is obvious that ventilation decrease in humans in cold air leads to reduction of oxygen consumption, i.e. to hypoxia. It is possible to assume that adaptation of Northerners is closely connected with cold and hypoxia. At hypoxia and under cold conditions the decrease of energy expenditure is the natural phenomenon. Y. Gauiter and M. Bonora, S. Wood consider that the fall of body temperature observable at hypoxia is a consequence of the decrease in oxygen consumption and reduction of energy expenditure. Besides, the decrease in oxygen consumption (Vo2) always precedes the fall of body temperature. In the work of C. Pedraz, J. Mortola it is shown that the external warming at hypoxia in newborn cats and dogs during restoration of body temperature up to the reference values is not accompanied by authentic change of metabolism. It remains lowered as under the previous conditions of hypoxia (before warming). It specifies that the fall in body temperature at hypoxia is a consequence instead of the reason of Vo2 fall. This is an important question for the human's adaptation--the influence of cold and hypoxia on spent energy. The paper presents the results of research into the effects of cold on resting and exercise energy expenditure among Northerners of the Russian North.

Effect of short-term exercise-heat acclimation on ventilatory and cerebral blood flow responses to passive heating at rest in humans.

PubMed

Fujii, Naoto; Tsuji, Bun; Honda, Yasushi; Kondo, Narihiko; Nishiyasu, Takeshi

2015-09-01

Hyperthermia induces hyperventilation and cerebral hypoperfusion in resting humans. We tested the hypothesis that short-term exercise-heat acclimation would alleviate those effects. Twenty healthy male subjects were divided into two groups that performed exercise training in the heat (TR-HEAT, n = 10) or cold (TR-COLD, n = 10). Before and after the training, the subjects in both groups participated in passive-heat tests at rest. Training was performed at 37°C (TR-HEAT) or 10°C (TR-COLD) and entailed four 20-min bouts of cycling at 50% peak oxygen uptake separated by 10-min recoveries daily for 6 consecutive days. After TR-HEAT, esophageal temperature was lowered when measured before and during passive heating, as was the esophageal temperature threshold for cutaneous active vasodilation, whereas plasma volume was increased (all P < 0.05). These traditional indices of successful heat acclimation were not all induced by TR-COLD (all P > 0.05). TR-HEAT had no significant effect on passive heating-induced increases in minute ventilation, even when evaluated as the esophageal temperature threshold for increases in minute ventilation and the slope relating minute ventilation to esophageal temperature (all P > 0.05). By contrast, TR-HEAT attenuated the passive heating-induced reduction in the cerebral vascular conductance index (middle cerebral artery mean blood velocity/mean arterial pressure) (all P < 0.05). TR-COLD did not attenuate the increase in minute ventilation or the decrease in the cerebral vascular conductance index observed during passive heating (all P > 0.05). These data suggest that in resting heated humans, short-term heat acclimation achieved through moderate-intensity exercise training (i.e., 50% peak oxygen uptake) in the heat does not influence hyperthermia-induced hyperventilation, but it does potentially attenuate cerebral hypoperfusion. Copyright © 2015 the American Physiological Society.

Crop-model assisted phenomics and genome-wide association study for climate adaptation of indica rice. 2. Thermal stress and spikelet sterility.

PubMed

Dingkuhn, Michael; Pasco, Richard; Pasuquin, Julie Mae; Damo, Jean; Soulié, Jean-Christophe; Raboin, Louis-Marie; Dusserre, Julie; Sow, Abdoulaye; Manneh, Baboucarr; Shrestha, Suchit; Kretzschmar, Tobias

2017-07-10

Low night and high day temperatures during sensitive reproductive stages cause spikelet sterility in rice. Phenotyping of tolerance traits in the field is difficult because of temporal interactions with phenology and organ temperature differing from ambient. Physiological models can be used to separate these effects. A 203-accession indica rice diversity panel was phenotyped for sterility in ten environments in Senegal and Madagascar and climate data were recorded. Here we report on sterility responses while a companion study reported on phenology. The objectives were to improve the RIDEV model of rice thermal sterility, to estimate response traits by fitting model parameters, and to link the response traits to genomic regions through genome-wide association studies (GWAS). RIDEV captured 64% of variation of sterility when cold acclimation during vegetative stage was simulated, but only 38% when it was not. The RIDEV parameters gave more and stronger quantitative trait loci (QTLs) than index variables derived more directly from observation. The 15 QTLs identified at P<1 × 10-5 (33 at P<1 × 10-4) were related to sterility effects of heat, cold, cold acclimation, or unexplained causes (baseline sterility). Nine annotated genes were found on average within the 50% linkage disequilibrium (LD) region. Among them, one to five plausible candidate genes per QTL were identified based on known expression profiles (organ, stage, stress factors) and function. Meiosis-, development- and flowering-related genes were frequent, as well a stress signaling kinases and transcription factors. Putative epigenetic factors such as DNA methylases or histone-related genes were frequent in cold-acclimation QTLs, and positive-effect alleles were frequent in cold-tolerant highland rice from Madagascar. The results indicate that epigenetic control of acclimation may be important in indica rice genotypes adapted to cool environments. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Subcutaneous and Intramuscular Hemodynamics and Oxygenation After Cold-Spray Application as Monitored by Near-Infrared Spectroscopy

PubMed Central

Shadgan, Babak; Pakravan, Amir H.; Hoens, Alison; Reid, W. Darlene

2015-01-01

Context Vapocoolant spray, commonly known as cold spray (CS), is a cryotherapy modality used in sports medicine, athletic training, and rehabilitation settings. Proposed physiologic effects of cryotherapy modalities include reductions in tissue blood flow, oxygenation, and cell metabolism in addition to attenuation of pain perception attributed to reduced superficial nerve conduction velocity. Objective To examine the effects of CS on subcutaneous and intramuscular blood flow and oxygenation on the thigh muscle using near-infrared spectroscopy, an optical method to monitor changes in tissue oxygenated (O2Hb), deoxygenated (HHb), and total (tHb) hemoglobin. Design Cross-sectional study. Setting Muscle Biophysics Laboratory. Patients or Other Participants Participants were 13 healthy adults (8 men, 5 women; age = 37.4 ± 6 years, body mass index = 27.4 ± 2.6, adipose tissue thickness = 7.2 ± 1.8 mm). Intervention(s) Conventional CS was applied to the vastus medialis muscles. Main Outcome Measure(s) Changes in chromophore concentrations of O2Hb, HHb, and tHb at superficial and deep layers were monitored for 5 minutes using a 2-channel near-infrared spectroscopy. Results Thirty seconds after CS application, we observed a decrease from baseline in O2Hb and tHb only in the superficial layer that was maintained for 3 minutes. Conclusions Application of CS induced a transient change in blood flow and oxygenation of the superficial tissues with no change in deeper tissues over the healthy vastus medialis muscle. The limited physiologic effect of CS on the superficial hemodynamics and oxygenation of limb muscles may limit the therapeutic benefit of this cryotherapy modality to a temporary analgesic effect, a hypothesis that warrants a clinical trial on traumatized muscles. PMID:26098273

Juvenile onset depression alters cardiac autonomic balance in response to psychological and physical challenges

PubMed Central

Bylsma, Lauren M.; Yaroslavsky, Ilya; Rottenberg, Jonathan; Jennings, J. Richard; George, Charles J.; Kiss, Enikő; Kapornai, Krisztina; Halas, Kitti; Dochnal, Roberta; Lefkovics, Eszter; Benák, István; Baji, Ildikó; Vetró, Ágnes; Kovacs, Maria

2015-01-01

Cardiac autonomic balance (CAB) indexes the ratio of parasympathetic to sympathetic activation (Berntson, Norman, Hawkley, & Cacioppo, 2008), and is believed to reflect overall autonomic flexibility in the face of environmental challenges. However, CAB has not been examined in depression. We examined changes in CAB and other physiological variables in 179 youth with a history of juvenile onset depression (JOD) and 161 healthy controls, in response to two psychological (unsolvable puzzle, sad film) and two physical (handgrip, and forehead cold pressor) challenges. In repeated measures analyses, controls showed expected reductions in CAB for both the handgrip and unsolvable puzzle, reflecting a shift to sympathetic relative to parasympathetic activation. By contrast, JOD youth showed increased CAB from baseline for both tasks (ps<.05). No effects were found for the forehead cold pressor or sad film tasks, suggesting that CAB differences may arise under conditions requiring greater attentional control or sustained effort. PMID:26225465

Effects of short-term hypothermal and contrast exposure on immunophysiological parameters of laboratory animals.

PubMed

Kalenova, L F; Fisher, T A; Suhovey, J G; Besedin, I M

2009-05-01

Experiments on inbred animals showed that short-term exposure in cold water significantly modified structural and functional parameters of the immune system at different levels of its organization, from bone marrow hemopoiesis to effector stage of the immune response to antigen. The thermal factor caused changes in nonspecific and specific mechanisms of the immune system. Hypothermal exposure (7-9 degrees C, 5 sec) increased the thymic index and bone marrow lymphocyte count, reduced absorption capacity and stimulated metabolic activity of phagocytes, stimulated cell-mediated and suppressed humoral immunity. Contrast exposure in cold and hot water (7-9 degrees C, 5 sec/40-42 degrees C, 30 sec) increased monocyte count in bone marrow and reduced it in the their peripheral blood, reduced metabolic activity of phagocytes, stimulated cell-mediated and suppressed humoral immunity. These data demonstrate physiological mechanisms of interactions between the thermoregulatory and immune systems.

Syndecan-1 Is Required to Maintain Intradermal Fat and Prevent Cold Stress

PubMed Central

Wollny, Damian; Clark, Rod J.; Roopra, Avtar; Colman, Ricki J.; MacDougald, Ormond A.; Shedd, Timothy A.; Nelson, David W.; Yen, Mei-I; Yen, Chi-Liang Eric; Alexander, Caroline M.

2014-01-01

Homeostatic temperature regulation is fundamental to mammalian physiology and is controlled by acute and chronic responses of local, endocrine and nervous regulators. Here, we report that loss of the heparan sulfate proteoglycan, syndecan-1, causes a profoundly depleted intradermal fat layer, which provides crucial thermogenic insulation for mammals. Mice without syndecan-1 enter torpor upon fasting and show multiple indicators of cold stress, including activation of the stress checkpoint p38α in brown adipose tissue, liver and lung. The metabolic phenotype in mutant mice, including reduced liver glycogen, is rescued by housing at thermoneutrality, suggesting that reduced insulation in cool temperatures underlies the observed phenotypes. We find that syndecan-1, which functions as a facultative lipoprotein uptake receptor, is required for adipocyte differentiation in vitro. Intradermal fat shows highly dynamic differentiation, continuously expanding and involuting in response to hair cycle and ambient temperature. This physiology probably confers a unique role for Sdc1 in this adipocyte sub-type. The PPARγ agonist rosiglitazone rescues Sdc1−/− intradermal adipose tissue, placing PPARγ downstream of Sdc1 in triggering adipocyte differentiation. Our study indicates that disruption of intradermal adipose tissue development results in cold stress and complex metabolic pathology. PMID:25101993

Wind constraints on the thermoregulation of high mountain lizards.

PubMed

Ortega, Zaida; Mencía, Abraham; Pérez-Mellado, Valentín

2017-03-01

Thermal biology of lizards affects their overall physiological performance. Thus, it is crucial to study how abiotic constraints influence thermoregulation. We studied the effect of wind speed on thermoregulation in an endangered mountain lizard (Iberolacerta aurelioi). We compared two populations of lizards: one living in a sheltered rocky area and the other living in a mountain ridge, exposed to strong winds. The preferred temperature range of I. aurelioi, which reflects thermal physiology, was similar in both areas, and it was typical of a cold specialist. Although the thermal physiology of lizards and the structure of the habitat were similar, the higher wind speed in the exposed population was correlated with a significant decrease in the effectiveness thermoregulation, dropping from 0.83 to 0.74. Our results suggest that wind reduces body temperatures in two ways: via direct convective cooling of the animal and via convective cooling of the substrate, which causes conductive cooling of the animal. The detrimental effect of wind on thermoregulatory effectiveness is surprising, since lizards are expected to thermoregulate more effectively in more challenging habitats. However, wind speed would affect the costs and benefits of thermoregulation in more complex ways than just the cooling of animals and their habitats. For example, it may reduce the daily activity, increase desiccation, or complicate the hunting of prey. Finally, our results imply that wind should also be considered when developing conservation strategies for threatened ectotherms.

Wind constraints on the thermoregulation of high mountain lizards

NASA Astrophysics Data System (ADS)

Ortega, Zaida; Mencía, Abraham; Pérez-Mellado, Valentín

2017-03-01

Thermal biology of lizards affects their overall physiological performance. Thus, it is crucial to study how abiotic constraints influence thermoregulation. We studied the effect of wind speed on thermoregulation in an endangered mountain lizard ( Iberolacerta aurelioi). We compared two populations of lizards: one living in a sheltered rocky area and the other living in a mountain ridge, exposed to strong winds. The preferred temperature range of I. aurelioi, which reflects thermal physiology, was similar in both areas, and it was typical of a cold specialist. Although the thermal physiology of lizards and the structure of the habitat were similar, the higher wind speed in the exposed population was correlated with a significant decrease in the effectiveness thermoregulation, dropping from 0.83 to 0.74. Our results suggest that wind reduces body temperatures in two ways: via direct convective cooling of the animal and via convective cooling of the substrate, which causes conductive cooling of the animal. The detrimental effect of wind on thermoregulatory effectiveness is surprising, since lizards are expected to thermoregulate more effectively in more challenging habitats. However, wind speed would affect the costs and benefits of thermoregulation in more complex ways than just the cooling of animals and their habitats. For example, it may reduce the daily activity, increase desiccation, or complicate the hunting of prey. Finally, our results imply that wind should also be considered when developing conservation strategies for threatened ectotherms.

Seasonal cues induce phenotypic plasticity of Drosophila suzukii to enhance winter survival.

PubMed

Shearer, Peter W; West, Jessica D; Walton, Vaughn M; Brown, Preston H; Svetec, Nicolas; Chiu, Joanna C

2016-03-22

As global climate change and exponential human population growth intensifies pressure on agricultural systems, the need to effectively manage invasive insect pests is becoming increasingly important to global food security. Drosophila suzukii is an invasive pest that drastically expanded its global range in a very short time since 2008, spreading to most areas in North America and many countries in Europe and South America. Preliminary ecological modeling predicted a more restricted distribution and, for this reason, the invasion of D. suzukii to northern temperate regions is especially unexpected. Investigating D. suzukii phenology and seasonal adaptations can lead to a better understanding of the mechanisms through which insects express phenotypic plasticity, which likely enables invasive species to successfully colonize a wide range of environments. We describe seasonal phenotypic plasticity in field populations of D. suzukii. Specifically, we observed a trend of higher proportions of flies with the winter morph phenotype, characterized by darker pigmentation and longer wing length, as summer progresses to winter. A laboratory-simulated winter photoperiod and temperature (12:12 L:D and 10 °C) were sufficient to induce the winter morph phenotype in D. suzukii. This winter morph is associated with increased survival at 1 °C when compared to the summer morph, thus explaining the ability of D. suzukii to survive cold winters. We then used RNA sequencing to identify gene expression differences underlying seasonal differences in D. suzukii physiology. Winter morph gene expression is consistent with known mechanisms of cold-hardening such as adjustments to ion transport and up-regulation of carbohydrate metabolism. In addition, transcripts involved in oogenesis and DNA replication were down-regulated in the winter morph, providing the first molecular evidence of a reproductive diapause in D. suzukii. To date, D. suzukii cold resistance studies suggest that this species cannot overwinter in northern locations, e.g. Canada, even though they are established pests in these regions. Combining physiological investigations with RNA sequencing, we present potential mechanisms by which D. suzukii can overwinter in these regions. This work may contribute to more accurate population models that incorporate seasonal variation in physiological parameters, leading to development of better management strategies.

Ecological and physiological thermal niches to understand distribution of Chagas disease vectors in Latin America.

PubMed

DE LA Vega, G J; Schilman, P E

2018-03-01

In order to assess how triatomines (Hemiptera, Reduviidae), Chagas disease vectors, are distributed through Latin America, we analysed the relationship between the ecological niche and the limits of the physiological thermal niche in seven species of triatomines. We combined two methodological approaches: species distribution models, and physiological tolerances. First, we modelled the ecological niche and identified the most important abiotic factor for their distribution. Then, thermal tolerance limits were analysed by measuring maximum and minimum critical temperatures, upper lethal temperature, and 'chill-coma recovery time'. Finally, we used phylogenetic independent contrasts to analyse the link between limiting factors and the thermal tolerance range for the assessment of ecological hypotheses that provide a different outlook for the geo-epidemiology of Chagas disease. In triatomines, thermo-tolerance range increases with increasing latitude mainly due to better cold tolerances, suggesting an effect of thermal selection. In turn, physiological analyses show that species reaching southernmost areas have a higher thermo-tolerance than those with tropical distributions, denoting that thermo-tolerance is limiting the southern distribution. Understanding the latitudinal range along its physiological limits of disease vectors may prove useful to test ecological hypotheses and improve strategies and efficiency of vector control at the local and regional levels. © 2017 The Royal Entomological Society.

Radial Pressure Pulse and Heart Rate Variability in Heat- and Cold-Stressed Humans

PubMed Central

Huang, Chin-Ming; Chang, Hsien-Cheh; Kao, Shung-Te; Li, Tsai-Chung; Wei, Ching-Chuan; Chen, Chiachung; Liao, Yin-Tzu; Chen, Fun-Jou

2011-01-01

This study aims to explore the effects of heat and cold stress on the radial pressure pulse (RPP) and heart rate variability (HRV). The subjects immersed their left hand into 45°C and 7°C water for 2 minutes. Sixty healthy subjects (age 25 ± 4 yr; 29 men and 31 women) were enrolled in this study. All subjects underwent the supine temperature measurements of the bilateral forearms, brachial arterial blood pressure, HRV and RPP with a pulse analyzer in normothermic conditions, and thermal stresses. The power spectral low-frequency (LF) and high-frequency (HF) components of HRV decreased in the heat test and increased in the cold test. The heat stress significantly reduced radial augmentation index (AIr) (P < .05), but the cold stress significantly increased AIr (P < .01). The spectral energy of RPP did not show any statistical difference in 0 ~ 10 Hz region under both conditions, but in the region of 10 ~ 50 Hz, there was a significant increase (P < .01) in the heat test and a significant decrease in the cold test (P < .01). The changes in AIr induced by heat and cold stress were significantly negatively correlated with the spectral energy in the region of 10 ~ 50 Hz (SE10−50 Hz) but not in the region of 0 ~ 10 Hz (SE0−10 Hz). The results demonstrated that the SE10−50 Hz, which only possessed a small percentage in total pulse energy, presented more physiological characteristics than the SE0−10 Hz under the thermal stresses. PMID:21113292

Baseline aortic pulse wave velocity is associated with central and peripheral pressor responses during the cold pressor test in healthy subjects.

PubMed

Borner, Anastasiya; Murray, Kyle; Trotter, Claire; Pearson, James

2017-07-01

Cold environmental temperatures increase sympathetic nerve activity and blood pressure, and increase the risk of acute cardiovascular events in aged individuals. The acute risk of cardiovascular events increases with aortic pulse wave velocity as well as elevated central and peripheral pulse pressures. The aim of this study was to examine the independent influence of aortic pulse wave velocity upon central and peripheral pressor responses to sympathetic activation via the cold pressor test (CPT). Twenty-two healthy subjects (age: 18-73 years) completed a CPT with the left hand immersed in 2-4°C water for 3 min. During the CPT, central (from: 36 ± 7 to: 51 ± 12 mmHg) and peripheral pulse pressure increased (from: 54 ± 7 to: 66 ± 11; both P  <   0.05). In all subjects the increase in central pulse pressure during the CPT was independently associated with baseline aortic pulse wave velocity ( r 2  = 0.221, P  =   0.027) but not age ( P  >   0.05). In a subset of subjects with higher arterial stiffness, the increase in peripheral pulse pressure during the CPT was independently associated with baseline aortic pulse wave velocity ( r 2  = 0.415, P  =   0.032) but not age ( P  >   0.05). These data indicate that central and peripheral pulse pressure responses during sympathetic activation are positively and independently associated with aortic pulse wave velocity through a wide age range. Decreasing aortic pulse wave velocity in aged individuals with elevated arterial stiffness may help reduce the incidence of acute cardiovascular events upon exposure to cold environmental temperatures. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Diurnal, seasonal, and sex patterns of heart rate in grip-restrained African giant rats (Cricetomys gambianus, Waterhouse).

PubMed

Dzenda, Tavershima; Ayo, Joseph O; Sinkalu, Victor O; Yaqub, Lukuman S

2015-10-01

This study was carried out to determine heart rate (HR) values, including diurnal, seasonal, and sex patterns, in the African giant rat (Cricetomys gambianus, Waterhouse). HR was measured using stethoscope in grip-restrained African giant rats of either sex (103 bucks and 98 does), live-trapped from a tropical Savannah, and caged individually in the laboratory during the harmattan (cold-dry), hot-dry, and rainy seasons over a 3-year period. The HR fluctuated between 90 and 210 beats per minute (bpm) throughout the study period. Diurnal changes in HR (mean ± SEM) during the hot-dry and rainy seasons were nonsignificant (P > 0.05), but the morning and afternoon values differed (P < 0.01) during the cold-dry season. The HR varied (P < 0.05) among seasons, with peak, nadir, and moderate values recorded during the cold-dry (165.8 ± 0.51 bpm), hot-dry (153.1 ± 0.74 bpm), and rainy (163.4 ± 0.70 bpm) seasons, respectively. Mean HR of bucks was lower than that of does during the cold-dry (P < 0.0001) and hot-dry (P < 0.01) seasons, but sex difference during the rainy season was insignificant (P > 0.05). Overall, mean HR was lower (P < 0.0001) in bucks (158.8 ± 0.53 bpm) than in does (164.8 ± 0.53 bpm). In conclusion, values of HR in African giant rats are shown for the first time. Season, sex, and daytime influenced the HR, and should be considered during clinical evaluations of the rats. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

The effect of air temperature and human thermal indices on mortality in Athens, Greece

NASA Astrophysics Data System (ADS)

Nastos, Panagiotis T.; Matzarakis, Andreas

2012-05-01

This paper investigates whether there is any association between the daily mortality for the wider region of Athens, Greece and the thermal conditions, for the 10-year period 1992-2001. The daily mortality datasets were acquired from the Hellenic Statistical Service and the daily meteorological datasets, concerning daily maximum and minimum air temperature, from the Hellinikon/Athens meteorological station, established at the headquarters of the Greek Meteorological Service. Besides, the daily values of the thermal indices Physiologically Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI) were evaluated in order to interpret the grade of physiological stress. The first step was the application of Pearson's χ 2 test to the compiled contingency tables, resulting in that the probability of independence is zero ( p = 0.000); namely, mortality is in close relation to the air temperature and PET/UTCI. Furthermore, the findings extracted by the generalized linear models showed that, statistically significant relationships ( p < 0.01) between air temperature, PET, UTCI and mortality exist on the same day. More concretely, on one hand during the cold period (October-March), a 10°C decrease in daily maximum air temperature, minimum air temperature, temperature range, PET and UTCI is related with an increase 13%, 15%, 2%, 7% and 6% of the probability having a death, respectively. On the other hand, during the warm period (April-September), a 10°C increase in daily maximum air temperature, minimum air temperature, temperature range, PET and UTCI is related with an increase 3%, 1%, 10%, 3% and 5% of the probability having a death, respectively. Taking into consideration the time lag effect of the examined parameters on mortality, it was found that significant effects of 3-day lag during the cold period appears against 1-day lag during the warm period. In spite of the general aspect that cold conditions seem to be favourable factors for daily mortality, the air temperature and PET/UTCI exceedances over specific thresholds depending on the distribution reveal that, very hot conditions are risk factors for the daily mortality.

Antarctica: a review of recent medical research.

PubMed

Olson, James J

2002-10-01

This article reviews recent developments and areas of research in Antarctic medical science. Nineteen nations are part of the Antarctic treaty and undertake research programmes in Antarctica. Medical science is a small but important part of these programmes. Areas that have been studied include aspects of cold physiology, ultraviolet light effects, endocrine changes (including polar T3 syndrome), alterations in immune function, chronobiology, psychology, microbiology, epidemiology and telemedicine. Antarctica has been recognized as the closest thing on Earth to a testing ground for aspects of space exploration and as such has been termed a space analogue.

The Physiological Role of Abscisic Acid in Eliciting Turion Morphogenesis.

PubMed Central

Smart, C. C.; Fleming, A. J.; Chaloupkova, K.; Hanke, D. E.

1995-01-01

The exogenous application of hormones has led to their implication in a number of processes within the plant. However, proof of their function in vivo depends on quantitative data demonstrating that the exogenous concentration used to elicit a response leads to tissue hormone levels within the physiological range. Such proof is often lacking in many investigations. We are using abscisic acid (ABA)-induced turion formation in Spirodela polyrrhiza L. to investigate the mechanism by which a hormone can trigger a morphogenic switch. In this paper, we demonstrate that the exogenous concentration of ABA used to induce turions leads to tissue concentrations of ABA within the physiological range, as quantified by both enzyme-linked immunosorbent assay and high-performance liquid chromatography/gas chromatography-electron capture detection analysis. These results are consistent with ABA having a physiological role in turion formation, and they provide an estimate of the changes in endogenous ABA concentration required if environmental effectors of turion formation (e.g. nitrate deficiency, cold) act via an increased level of ABA. In addition, we show that the (+)- and (-)-enantiomers of ABA are equally effective in inducing turions. Moreover, comparison of the ABA; levels attained after treatment with (+)-, (-)-, and ([plus or minus])-ABA and their effect on turion induction and comparison of the effectiveness of ABA on turion induction under different pH regimes suggest that ABA most likely interacts with a plasmalemma-located receptor system to induce turion formation. PMID:12228499

Effect of early feed restriction on physiological responses, performance and ascites incidence in broiler chickens raised in normal or cold environment.

PubMed

Mohammadalipour, R; Rahmani, H R; Jahanian, R; Riasi, A; Mohammadalipour, M; Nili, N

2017-02-01

Intensive selection of broilers for faster growth and better feed efficiency resulted in greater susceptibility to metabolic disorders such as ascites syndrome, which is one of the major causes of mortality and economic loss in broiler industry. Whereas cool temperature is one of the primary triggers for ascites, early feed restriction (FDR) significantly alleviates its incidence and mortality. However, little is known about effects of FDR, cold environmental temperature and their interaction on physiological responses in broiler chickens. For this purpose, 320 one-day-old male broilers were divided into two treatment groups of Ad libitum (Ad) and feed restricted (FR) with eight pen replicates each. Chickens in FR group underwent feed access limitation from days 7 to 14 of age. On day 21 half of the birds (four pens) in each group exposed to the cold temperature (CT) and the other half (four pens) continued at normal temperature (NT). Average daily feed intake, average daily weight gain and feed conversion ratio (FCR) were measured at days 7, 14, 21, 28 and 42. At 39 and 46 days of age two chicks with a BW around the pen average were selected from each pen and slaughtered after collecting blood samples. Then, relative weight of internal organs and right ventricle weight per total ventricle weight (RV : TV) ratio were calculated. Compared with NT group, CT birds had higher daily feed intake and FCR (P<0.05) from day 28 to 42. Cumulative ascites mortality in CT chickens was higher (P<0.001) than NT chicks. Within the CT group, ascites mortality in FR chickens was reduced (P<0.001) to 1.25% compared with 8.75% in Ad chicks. Birds in CT group had significantly (P<0.05) thicker right ventricle and greater relative weight of heart, hematocrit and triiodothyronine concentration. However, none of these parameters were affected by FDR. Under cold stress conditions, FDR reduced activity of alanine aminotransferase and aspartate aminotransferase (P<0.05). Serum triglyceride, cholesterol, high-density lipoprotein and total protein were not influenced by either temperature or feeding regimen. In conclusion, these findings suggest that FDR reduces ascites incidence mainly by allowing better development of internal organs, which helps them to cope with the high metabolic pressure and suffer less damage.

Impact of nesting material on mouse body temperature and physiology.

PubMed

Gaskill, Brianna N; Gordon, Christopher J; Pajor, Edmond A; Lucas, Jeffrey R; Davis, Jerry K; Garner, Joseph P

2013-02-17

In laboratories, mice are housed at 20-24 °C, which is below their lower critical temperature (≈30 °C). Thus, mice are potentially cold stressed, which can alter metabolism, immune function, and reproduction. These physiological changes reflect impaired wellbeing, and affect scientific outcomes. We hypothesized that nesting material would allow mice to alleviate cold stress by controlling their thermal microenvironment, thus insulating them, reducing heat loss and thermogenic processes. Naïve C57BL/6, CD-1, and BALB/c mice (24 male and 24 female/strain in groups of 3) were housed in standard cages at 20 °C either with or without 8 g nesting material for 4 weeks. Core body temperature was followed using intraperitoneal radio telemetry. The thermal properties of the nests were assessed using a thermal imaging camera, and related to nest quality. Higher scoring nests were negatively correlated with the mean radiated temperature and were thus more insulating. No effects of nesting material on body temperature were found. CD-1 mice with nesting material had higher end body weights than controls. No effect was seen in the other two strains. Mice with the telemetry implant had larger spleens than controls, possibly indicating an immune response to the implant or low level infection from the surgery. BALB/c mice express less mRNA for the UCP1 protein than mice without nesting material. This indicates that BALB/c's with nesting material do not utilize their brown fat to create heat as readily as controls. Nests can alleviate thermal discomfort by decreasing the amount of radiated heat and reduce the need for non-shivering thermogenesis. However, different strains appear to use different behavioral (through different primary modes of behavioral thermoregulation) and physiological strategies (utilizing thermogenesis to different degrees) to maintain a constant body temperature under cool standard laboratory ambient temperatures. Copyright © 2013 Elsevier Inc. All rights reserved.

Perspective Research Progress in Cold Responses of Capsella bursa-pastoris

PubMed Central

Noman, Ali; Kanwal, Hina; Khalid, Noreen; Sanaullah, Tayyaba; Tufail, Aasma; Masood, Atifa; Sabir, Sabeeh-ur-Rasool; Aqeel, Muhammad; He, Shuilin

2017-01-01

Plants respond to cold stress by modulating biochemical pathways and array of molecular events. Plant morphology is also affected by the onset of cold conditions culminating at repression in growth as well as yield reduction. As a preventive measure, cascades of complex signal transduction pathways are employed that permit plants to endure freezing or chilling periods. The signaling pathways and related events are regulated by the plant hormonal activity. Recent investigations have provided a prospective understanding about plant response to cold stress by means of developmental pathways e.g., moderate growth involved in cold tolerance. Cold acclimation assays and bioinformatics analyses have revealed the role of potential transcription factors and expression of genes like CBF, COR in response to low temperature stress. Capsella bursa-pastoris is a considerable model plant system for evolutionary and developmental studies. On different occasions it has been proved that C. bursa-pastoris is more capable of tolerating cold than A. thaliana. But, the mechanism for enhanced low or freezing temperature tolerance is still not clear and demands intensive research. Additionally, identification and validation of cold responsive genes in this candidate plant species is imperative for plant stress physiology and molecular breeding studies to improve cold tolerance in crops. We have analyzed the role of different genes and hormones in regulating plant cold resistance with special reference to C. bursa-pastoris. Review of collected data displays potential ability of Capsella as model plant for improvement in cold stress regulation. Information is summarized on cold stress signaling by hormonal control which highlights the substantial achievements and designate gaps that still happen in our understanding. PMID:28855910

A vascular mechanism to explain thermally mediated variations in deep-body cooling rates during the immersion of profoundly hyperthermic individuals.

PubMed

Caldwell, Joanne N; van den Heuvel, Anne M J; Kerry, Pete; Clark, Mitchell J; Peoples, Gregory E; Taylor, Nigel A S

2018-04-01

What is the central question of this study? Does the cold-water immersion (14°C) of profoundly hyperthermic individuals induce reductions in cutaneous and limb blood flow of sufficient magnitude to impair heat loss relative to the size of the thermal gradient? What is the main finding and its importance? The temperate-water cooling (26°C) of profoundly hyperthermic individuals was found to be rapid and reproducible. A vascular mechanism accounted for that outcome, with temperature-dependent differences in cutaneous and limb blood flows observed during cooling. Decisions relating to cooling strategies must be based upon deep-body temperature measurements that have response dynamics consistent with the urgency for cooling. Physiologically trivial time differences for cooling the intrathoracic viscera of hyperthermic individuals have been reported between cold- and temperate-water immersion treatments. One explanation for that observation is reduced convective heat delivery to the skin during cold immersion, and this study was designed to test both the validity of that observation, and its underlying hypothesis. Eight healthy men participated in four head-out water immersions: two when normothermic, and two after exercise-induced, moderate-to-profound hyperthermia. Two water temperatures were used within each thermal state: temperate (26°C) and cold (14°C). Tissue temperatures were measured at three deep-body sites (oesophagus, auditory canal and rectum) and eight skin surfaces, with cutaneous vascular responses simultaneously evaluated from both forearms (laser-Doppler flowmetry and venous-occlusion plethysmography). During the cold immersion of normothermic individuals, oesophageal temperature decreased relative to baseline (-0.31°C over 20 min; P < 0.05), whilst rectal temperature increased (0.20°C; P < 0.05). When rendered hyperthermic, oesophageal (-0.75°C) and rectal temperatures decreased (-0.05°C) during the transition period (<8.5 min, mostly in air at 22°C), with the former dropping to 37.5°C only 54 s faster when immersed in cold rather than in temperate water (P < 0.05). Minimal cutaneous vasoconstriction occurred during either normothermic immersion, whereas pronounced constriction was evident during both immersions when subjects were hyperthermic, with the colder water eliciting a greater vascular response (P < 0.05). It was concluded that the rapid intrathoracic cooling of asymptomatic, hyperthermic individuals in temperate water was a reproducible phenomenon, with slower than expected cooling in cold water brought about by stronger cutaneous vasoconstriction that reduced convective heat delivery to the periphery. © 2018 The Authors. Experimental Physiology © 2018 The Physiological Society.

Time Course of Physiological and Psychological Responses in Humans during a 20-Day Severe-Cold–Acclimation Programme

PubMed Central

Brazaitis, Marius; Eimantas, Nerijus; Daniuseviciute, Laura; Baranauskiene, Neringa; Skrodeniene, Erika; Skurvydas, Albertas

2014-01-01

The time course of physiological and psychological markers during cold acclimation (CA) was explored. The experiment included 17 controlled (i.e., until the rectal temperature reached 35.5°C or 170 min had elapsed; for the CA-17 session, the subjects (n = 14) were immersed in water for the same amount of time as that used in the CA-1 session) head-out water immersions at a temperature of 14°C over 20 days. The data obtained in this study suggest that the subjects exhibited a thermoregulatory shift from peripheral-to-central to solely central input thermoregulation, as well as from shivering to non-shivering thermogenesis throughout the CA. In the first six CA sessions, a hypothermic type of acclimation was found; further CA (CA-7 to CA-16) led to a transitional shift to a hypothermic–insulative type of acclimation. Interestingly, when the subjects were immersed in water for the same time as that used in the CA-1 session (CA-17), the CA led to a hypothermic type of acclimation. The presence of a metabolic type of thermogenesis was evident only under thermoneutral conditions. Cold-water immersion decreased the concentration of cold-stress markers, reduced the activity of the innate immune system, suppressed specific immunity to a lesser degree and yielded less discomfort and cold sensation. We found a negative correlation between body mass index and Δ metabolic heat production before and after CA. PMID:24722189

The physiological effects of oil, dispersant and dispersed oil on the bay mussel, Mytilus trossulus, in Arctic/Subarctic conditions.

PubMed

Counihan, Katrina L

2018-06-01

Increasing oil development around Alaska and other Arctic regions elevates the risk for another oil spill. Dispersants are used to mitigate the impact of an oil spill by accelerating natural degradation processes, but the reduced hydrophobicity of dispersed oil may increase its bioavailability to marine organisms. There is limited research on the effect of dispersed oil on cold water species and ecosystems. Therefore, spiked exposure tests were conducted with bay mussels (Mytilus trossulus) in seawater with non-dispersed oil, Corexit 9500 and oil dispersed with different concentrations of Corexit 9500. After three weeks of exposure, acute and chronic physiological impacts were determined. The majority of physiological responses occurred during the first seven days of exposure, with mussels exhibiting significant cytochrome P450 activity, superoxide dismutase activity and heat shock protein levels. Mussels exposed to non-dispersed oil also experienced immune suppression, reduced transcription and higher levels of mortality. After 21 days, mussels in all treatments exhibited evidence of genetic damage, tissue loss and a continued stress response. Bay mussels are useful as indicators of ecosystem health and recovery, and this study was an important step in understanding how non-dispersed oil, dispersant and dispersed oil affect the physiology of this sentinel species in Arctic/subarctic conditions. Copyright © 2018 Elsevier B.V. All rights reserved.

Brown adipose tissue and lipid metabolism.

PubMed

Heeren, Joerg; Scheja, Ludger

2018-06-01

This article explores how the interplay between lipid metabolism and thermogenic adipose tissues enables proper physiological adaptation to cold environments in rodents and humans. Cold exposure triggers systemic changes in lipid metabolism, which increases fatty acid delivery to brown adipose tissue (BAT) by various routes. Next to fatty acids generated intracellularly by de-novo lipogenesis or by lipolysis at lipid droplets, brown adipocytes utilize fatty acids released by white adipose tissue (WAT) for adaptive thermogenesis. WAT-derived fatty acids are internalized directly by BAT, or indirectly after hepatic conversion to very low-density lipoproteins and acylcarnitines. In the postprandial state, chylomicrons hydrolyzed by lipoprotein lipase - activated specifically in thermogenic adipocytes - are the predominant fatty acid source. Cholesterol-enriched chylomicron remnants and HDL generated by intravascular lipolysis in BAT are cleared more rapidly by the liver, explaining the antiatherogenic effects of BAT activation. Notably, increased cholesterol flux and elevated hepatic synthesis of bile acids under cold exposure further promote BAT-dependent thermogenesis. Although pathways providing fatty acids for activated BAT have been identified, more research is needed to understand the integration of lipid metabolism in BAT, WAT and liver, and to determine the relevance of BAT for human energy metabolism.

Master of all trades: thermal acclimation and adaptation of cardiac function in a broadly distributed marine invasive species, the European green crab, Carcinus maenas.

PubMed

Tepolt, Carolyn K; Somero, George N

2014-04-01

As global warming accelerates, there is increasing concern about how ecosystems may change as a result of species loss and replacement. Here, we examined the thermal physiology of the European green crab (Carcinus maenas Linnaeus 1758), a globally invasive species, along three parallel thermal gradients in its native and invasive ranges. At each site, we assessed cardiac physiology to determine heat and cold tolerance and acclimatory plasticity. We found that, overall, the species is highly tolerant of both heat and cold, and that it survives higher temperatures than co-occurring native marine crustaceans. Further, we found that both heat and cold tolerance are plastic in response to short-term acclimation (18-31 days at either 5 or 25°C). Comparing patterns within ranges, we found latitudinal gradients in thermal tolerance in the native European range and in the invasive range in eastern North America. This pattern is strongest in the native range, and likely evolved there. Because of a complicated invasion history, the latitudinal pattern in the eastern North American invasive range may be due either to rapid adaptation post-invasion or to adaptive differences between the ancestral populations that founded the invasion. Overall, the broad thermal tolerance ranges of green crabs, which may facilitate invasion of novel habitats, derive from high inherent eurythermality and acclimatory plasticity and potentially adaptive differentiation among populations. The highly flexible physiology that results from these capacities may represent the hallmark of a successful invasive species, and may provide a model for success in a changing world.

Physiological minimum temperatures for root growth in seven common European broad-leaved tree species.

PubMed

Schenker, Gabriela; Lenz, Armando; Körner, Christian; Hoch, Günter

2014-03-01

Temperature is the most important factor driving the cold edge distribution limit of temperate trees. Here, we identified the minimum temperatures for root growth in seven broad-leaved tree species, compared them with the species' natural elevational limits and identified morphological changes in roots produced near their physiological cold limit. Seedlings were exposed to a vertical soil-temperature gradient from 20 to 2 °C along the rooting zone for 18 weeks. In all species, the bulk of roots was produced at temperatures above 5 °C. However, the absolute minimum temperatures for root growth differed among species between 2.3 and 4.2 °C, with those species that reach their natural distribution limits at higher elevations also tending to have lower thermal limits for root tissue formation. In all investigated species, the roots produced at temperatures close to the thermal limit were pale, thick, unbranched and of reduced mechanical strength. Across species, the specific root length (m g(-1) root) was reduced by, on average, 60% at temperatures below 7 °C. A significant correlation of minimum temperatures for root growth with the natural high elevation limits of the investigated species indicates species-specific thermal requirements for basic physiological processes. Although these limits are not necessarily directly causative for the upper distribution limit of a species, they seem to belong to a syndrome of adaptive processes for life at low temperatures. The anatomical changes at the cold limit likely hint at the mechanisms impeding meristematic activity at low temperatures.

Intermittent cold exposure enhances fat accumulation in mice.

PubMed

Yoo, Hyung Sun; Qiao, Liping; Bosco, Chris; Leong, Lok-Hei; Lytle, Nikki; Feng, Gen-Sheng; Chi, Nai-Wen; Shao, Jianhua

2014-01-01

Due to its high energy consuming characteristics, brown adipose tissue (BAT) has been suggested as a key player in energy metabolism. Cold exposure is a physiological activator of BAT. Intermittent cold exposure (ICE), unlike persistent exposure, is clinically feasible. The main objective of this study was to investigate whether ICE reduces adiposity in C57BL/6 mice. Surprisingly, we found that ICE actually increased adiposity despite enhancing Ucp1 expression in BAT and inducing beige adipocytes in subcutaneous white adipose tissue. ICE did not alter basal systemic insulin sensitivity, but it increased liver triglyceride content and secretion rate as well as blood triglyceride levels. Gene profiling further demonstrated that ICE, despite suppressing lipogenic gene expression in white adipose tissue and liver during cold exposure, enhanced lipogenesis between the exposure periods. Together, our results indicate that despite enhancing BAT recruitment, ICE in mice increases fat accumulation by stimulating de novo lipogenesis.

Intermittent Cold Exposure Enhances Fat Accumulation in Mice

PubMed Central

Yoo, Hyung sun; Qiao, Liping; Bosco, Chris; Leong, Lok-Hei; Lytle, Nikki; Feng, Gen-Sheng; Chi, Nai-Wen; Shao, Jianhua

2014-01-01

Due to its high energy consuming characteristics, brown adipose tissue (BAT) has been suggested as a key player in energy metabolism. Cold exposure is a physiological activator of BAT. Intermittent cold exposure (ICE), unlike persistent exposure, is clinically feasible. The main objective of this study was to investigate whether ICE reduces adiposity in C57BL/6 mice. Surprisingly, we found that ICE actually increased adiposity despite enhancing Ucp1 expression in BAT and inducing beige adipocytes in subcutaneous white adipose tissue. ICE did not alter basal systemic insulin sensitivity, but it increased liver triglyceride content and secretion rate as well as blood triglyceride levels. Gene profiling further demonstrated that ICE, despite suppressing lipogenic gene expression in white adipose tissue and liver during cold exposure, enhanced lipogenesis between the exposure periods. Together, our results indicate that despite enhancing BAT recruitment, ICE in mice increases fat accumulation by stimulating de novo lipogenesis. PMID:24789228

Preparing for Hiking and Rock-Climbing At Altitude

NASA Technical Reports Server (NTRS)

Greenleaf, John E.

2002-01-01

Exposure to altitude with or without exercise usually results in body dehydration. Psychological and physiological preparation for exercise at altitude involves consideration of maintaining body warmth in a cool to cold environment with progressively lower oxygen content (partial pressure) as altitude increases. However, this discussion will focus on altitudes below 14,000 it where supplemental breathing oxygen is not required for sojourns of healthy people. Background information and helpful advice for those who exercise in the cold can be found in selected articles in the 2001 Winter Issue of this Newsletter: M.B. Ducharme, Get ready for outdoor winter play: prepare yourself for the cold; C. O'Brien, Think layers when dressing for exercise in the cold; B.G. Rice and R. Ellis, Let it snow, let it snow, let it snow - but be aware of winter hazards; and L.B. Mayers, Exercise - induced asthma.

Investigating the associations between hydration and exercise performance: methodology and limitations.

PubMed

Maughan, Ronald J

2012-11-01

Loss of body water, if sufficiently severe, impairs most physiological functions, but the body water content fluctuates over the course of a normal day with no implications for physical or mental performance. The point at which an effect of dehydration becomes apparent has been the subject of much debate, in part, at least, because of the different tests that have been applied, differences in the methodologies used to induce dehydration and also because of differences in the fitness and other physiological characteristics of the subjects studied. The act of drinking itself and the conscious denial of access to water will also have implications for subjective responses to the exercise task. In many published studies, it is difficult to separate the effects of ingestion of water from those of carbohydrate, electrolytes, and other drink components. Nevertheless, there is good evidence that drinking appropriate amounts of water, especially cold water, can enhance exercise performance in many situations. © 2012 International Life Sciences Institute.

Osmotic versus adrenergic control of ion transport by ionocytes of Fundulus heteroclitus in the cold.

PubMed

Tait, Janet C; Mercer, Evan W; Gerber, Lucie; Robertson, George N; Marshall, William S

2017-01-01

In eurythermic vertebrates, acclimation to the cold may produce changes in physiological control systems. We hypothesize that relatively direct osmosensitive control will operate better than adrenergic receptor mediated control of ion transport in cold vs. warm conditions. Fish were acclimated to full strength seawater (SW) at 21°C and 5°C for four weeks, gill samples and blood were taken and opercular epithelia mounted in Ussing style chambers. Short-circuit current (I sc ) at 21°C and 5°C (measured at acclimation temperature), was significantly inhibited by the α 2 -adrenergic agonist clonidine but the ED 50 dose was significantly higher in cold conditions (93.8±16.4nM) than in warm epithelia (47.8±8.1nM) and the maximum inhibition was significantly lower in cold (-66.1±2.2%) vs. warm conditions (-85.6±1.3%), indicating lower sensitivity in the cold. β-Adrenergic responses were unchanged. Hypotonic inhibition of I sc , was higher in warm acclimated (-95%), compared to cold acclimated fish (-75%), while hypertonic stimulations were the same, indicating equal responsiveness to hyperosmotic stimuli. Plasma osmolality was significantly elevated in cold acclimated fish and, by TEM, gill ionocytes from cold acclimated fish had significantly shorter mitochondria. These data are consistent with a shift in these eurythermic animals from complex adrenergic control to relatively simple biomechanical osmotic control of ion secretion in the cold. Copyright © 2016. Published by Elsevier Inc.

The β3-adrenergic receptor is dispensable for browning of adipose tissues.

PubMed

de Jong, Jasper M A; Wouters, René T F; Boulet, Nathalie; Cannon, Barbara; Nedergaard, Jan; Petrovic, Natasa

2017-06-01

Brown and brite/beige adipocytes are attractive therapeutic targets to treat metabolic diseases. To maximally utilize their functional potential, further understanding is required about their identities and their functional differences. Recent studies with β 3 -adrenergic receptor knockout mice reported that brite/beige adipocytes, but not classical brown adipocytes, require the β 3 -adrenergic receptor for cold-induced transcriptional activation of thermogenic genes. We aimed to further characterize this requirement of the β 3 -adrenergic receptor as a functional distinction between classical brown and brite/beige adipocytes. However, when comparing wild-type and β 3 -adrenergic receptor knockout mice, we observed no differences in cold-induced thermogenic gene expression ( Ucp1 , Pgc1a , Dio2 , and Cidea ) in brown or white (brite/beige) adipose tissues. Irrespective of the duration of the cold exposure or the sex of the mice, we observed no effect of the absence of the β 3 -adrenergic receptor. Experiments with the β 3 -adrenergic receptor agonist CL-316,243 verified the functional absence of β 3 -adrenergic signaling in these knockout mice. The β 3 -adrenergic receptor knockout model in the present study was maintained on a FVB/N background, whereas earlier reports used C57BL/6 and 129Sv mice. Thus our data imply background-dependent differences in adrenergic signaling mechanisms in response to cold exposure. Nonetheless, the present data indicate that the β 3 -adrenergic receptor is dispensable for cold-induced transcriptional activation in both classical brown and, as opposed to earlier studies, brite/beige cells. Copyright © 2017 the American Physiological Society.

Transcriptome Dynamics in Mango Fruit Peel Reveals Mechanisms of Chilling Stress

PubMed Central

Sivankalyani, Velu; Sela, Noa; Feygenberg, Oleg; Zemach, Hanita; Maurer, Dalia; Alkan, Noam

2016-01-01

Cold storage is considered the most effective method for prolonging fresh produce storage. However, subtropical fruit is sensitive to cold. Symptoms of chilling injury (CI) in mango include red and black spots that start from discolored lenticels and develop into pitting. The response of ‘Keitt’ mango fruit to chilling stress was monitored by transcriptomic, physiological, and microscopic analyses. Transcriptomic changes in the mango fruit peel were evaluated during optimal (12°C) and suboptimal (5°C) cold storage. Two days of chilling stress upregulated genes involved in the plant stress response, including those encoding transmembrane receptors, calcium-mediated signal transduction, NADPH oxidase, MAP kinases, and WRKYs, which can lead to cell death. Indeed, cell death was observed around the discolored lenticels after 19 days of cold storage at 5°C. Localized cell death and cuticular opening in the lumen of discolored lenticels were correlated with increased general decay during shelf-life storage, possibly due to fungal penetration. We also observed increased phenolics accumulation around the discolored lenticels, which was correlated with the biosynthesis of phenylpropanoids that were probably transported from the resin ducts. Increased lipid peroxidation was observed during CI by both the biochemical malondialdehyde method and a new non-destructive luminescent technology, correlated to upregulation of the α-linolenic acid oxidation pathway. Genes involved in sugar metabolism were also induced, possibly to maintain osmotic balance. This analysis provides an in-depth characterization of mango fruit response to chilling stress and could lead to the development of new tools, treatments and strategies to prolong cold storage of subtropical fruit. PMID:27812364

Reversal of Physiological Deficits Caused by Diminished Levels of Peptidylglycine α-Amidating Monooxygenase by Dietary Copper

PubMed Central

Bousquet-Moore, D.; Ma, X. M.; Nillni, E. A.; Czyzyk, T. A.; Pintar, J. E.; Eipper, B. A.; Mains, R. E.

2009-01-01

Amidated peptides are critically involved in many physiological functions. Genetic deletion of peptidylglycine α-amidating monooxygenase (PAM), the only enzyme that can synthesize these peptides, is embryonically lethal. The goal of the present study was the identification of physiological functions impaired by haploinsufficiency of PAM. Regulation of the hypothalamic-pituitary-thyroid axis and body temperature, functions requiring contributions from multiple amidated peptides, were selected for evaluation. Based on serum T4 and pituitary TSH-β mRNA levels, mice heterozygous for PAM (PAM+/−) were euthyroid at baseline. Feedback within the hypothalamic-pituitary-thyroid axis was impaired in PAM+/− mice made hypothyroid using a low iodine/propylthiouracil diet. Despite their normal endocrine response to cold, PAM+/− mice were unable to maintain body temperature as well as wild-type littermates when kept in a 4 C environment. When provided with additional dietary copper, PAM+/− mice maintained body temperature as well as wild-type mice. Pharmacological activation of vasoconstriction or shivering also allowed PAM+/− mice to maintain body temperature. Cold-induced vasoconstriction was deficient in PAM+/− mice. This deficit was eliminated in PAM+/− mice receiving a diet with supplemental copper. These results suggest that dietary deficiency of copper, coupled with genetic deficits in PAM, could result in physiological deficits in humans. PMID:19022883

Physiological processes during winter dormancy and their ecological significance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Havranek, W.M.; Tranquillini, W.

1995-07-01

Lengthy and severe winters require that trees in the forests of boreal and mountain zones undergo winter dormancy. Physiologically, a high resistance to subfreezing temperatures and concomitant dehydration are necessary. To accomplish this dormancy, both physiological and structural changes are needed at the cellular level that require induction by endogenous and photoperiodic control early in autumn. Endogenous rhythmicity promotes cold hardening in early autumn and the persistence of hardiness throughout the winter. Numerous physiological functions are maintained at a reduced level, or become completely inhibited during true winter dormancy. Winter hardiness also includes the capability to minimize water loss effectivelymore » when water uptake is severely impeded or impossible. Anatomical features such as tracheids act to minimize xylem embolism during frequent freeze-thaw cycles, and {open_quotes}crown{close_quotes} tissues enable buds to stay in a dehydrated and, thus, more resistant state during winter. Both these structural features are adaptations that contribute to the dominance of conifers in cold climates. Interestingly, deciduous tree species rather than evergreen conifers dominate in the most severe winter climates, although it is not clear whether limitations during winter, during the summer growth period, or during both are most limiting to conifer tree ecology. Additional work that evaluates the importance of winter and summer growth restriction, and their interaction, is needed before a comprehensive understanding of conifer tree ecophysiology will be possible.« less

Integration of body temperature into the analysis of energy expenditure in the mouse

PubMed Central

Abreu-Vieira, Gustavo; Xiao, Cuiying; Gavrilova, Oksana; Reitman, Marc L.

2015-01-01

Objectives We quantified the effect of environmental temperature on mouse energy homeostasis and body temperature. Methods The effect of environmental temperature (4–33 °C) on body temperature, energy expenditure, physical activity, and food intake in various mice (chow diet, high-fat diet, Brs3-/y, lipodystrophic) was measured using continuous monitoring. Results Body temperature depended most on circadian phase and physical activity, but also on environmental temperature. The amounts of energy expenditure due to basal metabolic rate (calculated via a novel method), thermic effect of food, physical activity, and cold-induced thermogenesis were determined as a function of environmental temperature. The measured resting defended body temperature matched that calculated from the energy expenditure using Fourier's law of heat conduction. Mice defended a higher body temperature during physical activity. The cost of the warmer body temperature during the active phase is 4–16% of total daily energy expenditure. Parameters measured in diet-induced obese and Brs3-/y mice were similar to controls. The high post-mortem heat conductance demonstrates that most insulation in mice is via physiological mechanisms. Conclusions At 22 °C, cold-induced thermogenesis is ∼120% of basal metabolic rate. The higher body temperature during physical activity is due to a higher set point, not simply increased heat generation during exercise. Most insulation in mice is via physiological mechanisms, with little from fur or fat. Our analysis suggests that the definition of the upper limit of the thermoneutral zone should be re-considered. Measuring body temperature informs interpretation of energy expenditure data and improves the predictiveness and utility of the mouse to model human energy homeostasis. PMID:26042200

Effect of pre-cooling, with and without thigh cooling, on strain and endurance exercise performance in the heat.

PubMed

Cotter, J D; Sleivert, G G; Roberts, W S; Febbraio, M A

2001-04-01

Body cooling before exercise (i.e. pre-cooling) reduces physiological strain in humans during endurance exercise in temperate and warm environments, usually improving performance. This study examined the effectiveness of pre-cooling humans by ice-vest and cold (3 degrees C) air, with (LC) and without (LW) leg cooling, in reducing heat strain and improving endurance performance in the heat (35 degrees C, 60% RH). Nine habitually-active males completed three trials, involving pre-cooling (LC and LW) or no pre-cooling (CON: 34 degrees C air) before 35-min cycle exercise: 20 min at approximately 65% VO2peak then a 15-min work-performance trial. At exercise onset, mean core (Tc, from oesophagus and rectum) and skin temperatures, forearm blood flow (FBF), heart rate (HR), and ratings of exertion, body temperature and thermal discomfort were lower in LW and LC than CON (P<0.05). They remained lower at 20 min [e.g. Tc: CON 38.4+/-0.2 (+/-S.E.), LW 37.9+/-0.1, and LC 37.8+/-0.1 degrees C; HR: 177+/-3, 163+/-3 and 167+/-3 b.p.m.), except that FBF was equivalent (P=0.10) between CON (15.5+/-1.6) and LW (13.6+/-1.0 ml.100 ml tissue(-1) x min(-1)). Subsequent power output was higher in LW (2.95+/-0.24) and LC (2.91+/-0.25) than in CON (2.52+/-0.28 W kg(-1), P=0.00, N=8), yet final Tc remained lower. Pre-cooling by ice-vest and cold air effectively reduced physiological and psychophysical strain and improved endurance performance in the heat, irrespective of whether thighs were warmed or cooled.

Variable Cold-Induced Brown Adipose Tissue Response to Thyroid Hormone Status

PubMed Central

Hasselgren, Per-Olof; Glasgow, Allison; Doyle, Ashley N.; Lee, Alice J.; Fox, Peter; Gautam, Shiva; Hennessey, James V.; Kolodny, Gerald M.

2017-01-01

Background: In addition to its role in adaptive thermogenesis, brown adipose tissue (BAT) may protect from weight gain, insulin resistance/diabetes, and metabolic syndrome. Prior studies have shown contradictory results regarding the influence of thyroid hormone (TH) levels on BAT volume and activity. The aim of this pilot study was to gain further insights regarding the effect of TH treatment on BAT function in adult humans by evaluating the BAT mass and activity prospectively in six patients, first in the hypothyroid and then in the thyrotoxic phase. Methods: The study subjects underwent 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) scanning after cold exposure to measure BAT mass and activity while undergoing treatment for differentiated thyroid cancer, first while hypothyroid following TH withdrawal at the time of the radioactive iodine treatment and then three to six months after starting TH suppressive treatment when they were iatrogenically thyrotoxic. Thermogenic and metabolic parameters were measured in both phases. Results: All study subjects had detectable BAT under cold stimulation in both the hypothyroid and thyrotoxic state. The majority but not all (4/6) subjects showed an increase in detectable BAT volume and activity under cold stimulation between the hypothyroid and thyrotoxic phase (total BAT volume: 72.0 ± 21.0 vs. 87.7 ± 16.5 mL, p = 0.25; total BAT activity 158.1 ± 72.8 vs. 189.0 ± 55.5 SUV*g/mL, p = 0.34). Importantly, circulating triiodothyronine was a stronger predictor of energy expenditure changes compared with cold-induced BAT activity. Conclusions: Iatrogenic hypothyroidism lasting two to four weeks does not prevent cold-induced BAT activation, while the use of TH to induce thyrotoxicosis does not consistently increase cold-induced BAT activity. It remains to be determined which physiological factors besides TH play a role in regulating BAT function. PMID:27750020

Variable Cold-Induced Brown Adipose Tissue Response to Thyroid Hormone Status.

PubMed

Gavrila, Alina; Hasselgren, Per-Olof; Glasgow, Allison; Doyle, Ashley N; Lee, Alice J; Fox, Peter; Gautam, Shiva; Hennessey, James V; Kolodny, Gerald M; Cypess, Aaron M

2017-01-01

In addition to its role in adaptive thermogenesis, brown adipose tissue (BAT) may protect from weight gain, insulin resistance/diabetes, and metabolic syndrome. Prior studies have shown contradictory results regarding the influence of thyroid hormone (TH) levels on BAT volume and activity. The aim of this pilot study was to gain further insights regarding the effect of TH treatment on BAT function in adult humans by evaluating the BAT mass and activity prospectively in six patients, first in the hypothyroid and then in the thyrotoxic phase. The study subjects underwent 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) scanning after cold exposure to measure BAT mass and activity while undergoing treatment for differentiated thyroid cancer, first while hypothyroid following TH withdrawal at the time of the radioactive iodine treatment and then three to six months after starting TH suppressive treatment when they were iatrogenically thyrotoxic. Thermogenic and metabolic parameters were measured in both phases. All study subjects had detectable BAT under cold stimulation in both the hypothyroid and thyrotoxic state. The majority but not all (4/6) subjects showed an increase in detectable BAT volume and activity under cold stimulation between the hypothyroid and thyrotoxic phase (total BAT volume: 72.0 ± 21.0 vs. 87.7 ± 16.5 mL, p = 0.25; total BAT activity 158.1 ± 72.8 vs. 189.0 ± 55.5 SUV*g/mL, p = 0.34). Importantly, circulating triiodothyronine was a stronger predictor of energy expenditure changes compared with cold-induced BAT activity. Iatrogenic hypothyroidism lasting two to four weeks does not prevent cold-induced BAT activation, while the use of TH to induce thyrotoxicosis does not consistently increase cold-induced BAT activity. It remains to be determined which physiological factors besides TH play a role in regulating BAT function.

Thermal-safety margins and the necessity of thermoregulatory behavior across latitude and elevation

PubMed Central

Sunday, Jennifer M.; Bates, Amanda E.; Kearney, Michael R.; Colwell, Robert K.; Dulvy, Nicholas K.; Longino, John T.; Huey, Raymond B.

2014-01-01

Physiological thermal-tolerance limits of terrestrial ectotherms often exceed local air temperatures, implying a high degree of thermal safety (an excess of warm or cold thermal tolerance). However, air temperatures can be very different from the equilibrium body temperature of an individual ectotherm. Here, we compile thermal-tolerance limits of ectotherms across a wide range of latitudes and elevations and compare these thermal limits both to air and to operative body temperatures (theoretically equilibrated body temperatures) of small ectothermic animals during the warmest and coldest times of the year. We show that extreme operative body temperatures in exposed habitats match or exceed the physiological thermal limits of most ectotherms. Therefore, contrary to previous findings using air temperatures, most ectotherms do not have a physiological thermal-safety margin. They must therefore rely on behavior to avoid overheating during the warmest times, especially in the lowland tropics. Likewise, species living at temperate latitudes and in alpine habitats must retreat to avoid lethal cold exposure. Behavioral plasticity of habitat use and the energetic consequences of thermal retreats are therefore critical aspects of species’ vulnerability to climate warming and extreme events. PMID:24616528

Thermal-safety margins and the necessity of thermoregulatory behavior across latitude and elevation.

PubMed

Sunday, Jennifer M; Bates, Amanda E; Kearney, Michael R; Colwell, Robert K; Dulvy, Nicholas K; Longino, John T; Huey, Raymond B

2014-04-15

Physiological thermal-tolerance limits of terrestrial ectotherms often exceed local air temperatures, implying a high degree of thermal safety (an excess of warm or cold thermal tolerance). However, air temperatures can be very different from the equilibrium body temperature of an individual ectotherm. Here, we compile thermal-tolerance limits of ectotherms across a wide range of latitudes and elevations and compare these thermal limits both to air and to operative body temperatures (theoretically equilibrated body temperatures) of small ectothermic animals during the warmest and coldest times of the year. We show that extreme operative body temperatures in exposed habitats match or exceed the physiological thermal limits of most ectotherms. Therefore, contrary to previous findings using air temperatures, most ectotherms do not have a physiological thermal-safety margin. They must therefore rely on behavior to avoid overheating during the warmest times, especially in the lowland tropics. Likewise, species living at temperate latitudes and in alpine habitats must retreat to avoid lethal cold exposure. Behavioral plasticity of habitat use and the energetic consequences of thermal retreats are therefore critical aspects of species' vulnerability to climate warming and extreme events.

Thermal, cardiac and adrenergic responses to repeated local cooling.

PubMed

Janský, L; Matousková, E; Vávra, V; Vybíral, S; Janský, P; Jandová, D; Knízková, I; Kunc, P

2006-01-01

The aim of this study was to ascertain whether repeated local cooling induces the same or different adaptational responses as repeated whole body cooling. Repeated cooling of the legs (immersion into 12 degrees C water up to the knees for 30 min, 20 times during 4 weeks = local cold adaptation - LCA) attenuated the initial increase in heart rate and blood pressure currently observed in control subjects immersed in cold water up to the knees. After LCA the initial skin temperature decrease tended to be lower, indicating reduced vasoconstriction. Heart rate and systolic blood pressure appeared to be generally lower during rest and during the time course of cooling in LCA humans, when compared to controls. All these changes seem to indicate attenuation of the sympathetic tone. In contrast, the sustained skin temperature in different areas of the body (finger, palm, forearm, thigh, chest) appeared to be generally lower in LCA subjects than in controls (except for temperatures on the forehead). Plasma levels of catecholamines (measured 20 and 40 min after the onset of cooling) were also not influenced by local cold adaptation. Locally cold adapted subjects, when exposed to whole body cold water immersion test, showed no change in the threshold temperature for induction of cold thermogenesis. This indicates that the hypothermic type of cold adaptation, typically occurring after systemic cold adaptation, does not appear after local cold adaptation of the intensity used. It is concluded that in humans the cold adaptation due to repeated local cooling of legs induces different physiological changes than systemic cold adaptation.

Physiological ecology of overwintering in hatchling turtles.

PubMed

Costanzo, Jon P; Lee, Richard E; Ultsch, Gordon R

2008-07-01

Temperate species of turtles hatch from eggs in late summer. The hatchlings of some species leave their natal nest to hibernate elsewhere on land or under water, whereas others usually remain inside the nest until spring; thus, post-hatching behavior strongly influences the hibernation ecology and physiology of this age class. Little is known about the habitats of and environmental conditions affecting aquatic hibernators, although laboratory studies suggest that chronically hypoxic sites are inhospitable to hatchlings. Field biologists have long been intrigued by the environmental conditions survived by hatchlings using terrestrial hibernacula, especially nests that ultimately serve as winter refugia. Hatchlings are unable to feed, although as metabolism is greatly reduced in hibernation, they are not at risk of starvation. Dehydration and injury from cold are more formidable challenges. Differential tolerances to these stressors may explain variation in hatchling overwintering habits among turtle taxa. Much study has been devoted to the cold-hardiness adaptations exhibited by terrestrial hibernators. All tolerate a degree of chilling, but survival of frost exposure depends on either freeze avoidance through supercooling or freeze tolerance. Freeze avoidance is promoted by behavioral, anatomical, and physiological features that minimize risk of inoculation by ice and ice-nucleating agents. Freeze tolerance is promoted by a complex suite of molecular, biochemical, and physiological responses enabling certain organisms to survive the freezing and thawing of extracellular fluids. Some species apparently can switch between freeze avoidance or freeze tolerance, the mode utilized in a particular instance of chilling depending on prevailing physiological and environmental conditions. (c) 2008 Wiley-Liss, Inc.

A Temperature-Independent Cold-Shock Protein Homolog Acts as a Virulence Factor in Xylella fastidiosa.

PubMed

Burbank, Lindsey P; Stenger, Drake C

2016-05-01

Xylella fastidiosa, causal agent of Pierce's disease (PD) of grapevine, is a fastidious organism that requires very specific conditions for replication and plant colonization. Cold temperatures reduce growth and survival of X. fastidiosa both in vitro and in planta. However, little is known regarding physiological responses of X. fastidiosa to temperature changes. Cold-shock proteins (CSP), a family of nucleic acid-binding proteins, act as chaperones facilitating translation at low temperatures. Bacterial genomes often encode multiple CSP, some of which are strongly induced following exposure to cold. Additionally, CSP contribute to the general stress response through mRNA stabilization and posttranscriptional regulation. A putative CSP homolog (Csp1) with RNA-binding activity was identified in X. fastidiosa Stag's Leap. The csp1 gene lacked the long 5' untranslated region characteristic of cold-inducible genes and was expressed in a temperature-independent manner. As compared with the wild type, a deletion mutant of csp1 (∆csp1) had decreased survival rates following cold exposure and salt stress in vitro. The deletion mutant also was significantly less virulent in grapevine, as compared with the wild type, in the absence of cold stress. These results suggest an important function of X. fastidiosa Csp1 in response to cellular stress and during plant colonization.

Interpopulational variation in the cold tolerance of a broadly distributed marine copepod

PubMed Central

Wallace, Gemma T.; Kim, Tiffany L.; Neufeld, Christopher J.

2014-01-01

Latitudinal trends in cold tolerance have been observed in many terrestrial ectotherms, but few studies have investigated interpopulational variation in the cold physiology of marine invertebrates. Here, the intertidal copepod Tigriopus californicus was used as a model system to study how local adaptation influences the cold tolerance of a broadly distributed marine crustacean. Among five populations spanning 18° in latitude, the following three metrics were used to compare cold tolerance: the temperature of chill-coma onset, the chill-coma recovery time and post-freezing recovery. In comparison to copepods from warmer southern latitudes, animals from northern populations exhibited lower chill-coma onset temperatures, shorter chill-coma recovery times and faster post-freezing recovery rates. Importantly, all three metrics showed a consistent latitudinal trend, suggesting that any single metric could be used equivalently in future studies investigating latitudinal variation in cold tolerance. Our results agree with previous studies showing that populations within a single species can display strong local adaptation to spatially varying climatic conditions. Thus, accounting for local adaptation in bioclimate models will be useful for understanding how broadly distributed species like T. californicus will respond to anthropogenic climate change. PMID:27293662

Interpopulational variation in the cold tolerance of a broadly distributed marine copepod.

PubMed

Wallace, Gemma T; Kim, Tiffany L; Neufeld, Christopher J

2014-01-01

Latitudinal trends in cold tolerance have been observed in many terrestrial ectotherms, but few studies have investigated interpopulational variation in the cold physiology of marine invertebrates. Here, the intertidal copepod Tigriopus californicus was used as a model system to study how local adaptation influences the cold tolerance of a broadly distributed marine crustacean. Among five populations spanning 18° in latitude, the following three metrics were used to compare cold tolerance: the temperature of chill-coma onset, the chill-coma recovery time and post-freezing recovery. In comparison to copepods from warmer southern latitudes, animals from northern populations exhibited lower chill-coma onset temperatures, shorter chill-coma recovery times and faster post-freezing recovery rates. Importantly, all three metrics showed a consistent latitudinal trend, suggesting that any single metric could be used equivalently in future studies investigating latitudinal variation in cold tolerance. Our results agree with previous studies showing that populations within a single species can display strong local adaptation to spatially varying climatic conditions. Thus, accounting for local adaptation in bioclimate models will be useful for understanding how broadly distributed species like T. californicus will respond to anthropogenic climate change.

Expression analysis and functional characterization of a novel cold-responsive gene CbCOR15a from Capsella bursa-pastoris.

PubMed

Zhou, Mingqi; Wu, Lihua; Liang, Jing; Shen, Chen; Lin, Juan

2012-05-01

The cold-responsive (COR) genes involved in C-repeat binding factor signaling pathway function essentially in cold acclimation of higher plants. A novel COR gene CbCOR15a from shepherd's purse (Capsella bursa-pastoris) was predicted to be a homolog of COR15 in Arabidopsis. The analysis of tissue specific expression pattern as well as characterization of the CbCOR15a promoter revealed that the expression of CbCOR15a was induced by coldness not only in leaves and stem but also in roots. Sequence analysis showed that a 909 bp promoter region of CbCOR15a contained two CRT/DRE elements, two ABRE elements, one auxin-responsive TGA-element and one MeJA-responsive CGTCA-motif. In young seedlings the expression of CbCOR15a could be apparently increased by SA, ABA, MeJA and IAA, and transiently increased by GA(3) accompanied by obvious feedback suppression. According to the altered physiological index values in tobacco under cold treatments, the overexpression of CbCOR15a significantly increased the cold tolerance of transgenic tobacco plants. It can be suggested that CbCOR15a was involved in cold response of Capsella bursa-pastoris associated with SA, ABA, MeJA, IAA and GA(3) regulation and confers enhanced cold acclimation in transgenic plants.

Recovery benefits of using a heat and moisture exchange mask during sprint exercise in cold temperatures.

PubMed

Seifert, John G; Frost, Jeremy; St Cyr, John A

2017-01-01

Breathing cold air can lead to bronchoconstriction and peripheral vasoconstriction, both of which could impact muscular performance by affecting metabolic demands during exercise. Successful solutions dealing with these physiological changes during exercise in the cold has been lacking; therefore, we investigated the influence of a heat and moisture exchange mask during exercise in the cold. There were three trial arms within this study: wearing the heat and moisture exchange mask during the rest periods in the cold, no-mask application during the rest periods in the cold, and a trial at room temperature (22°C). Eight subjects cycled in four 35 kJ sprint sessions with each session separated by 20 min rest period. Workload was 4% of body mass. Mean sprint times were faster with heat and moisture exchange mask and room temperature trial than cold, no-mask trial (133.8 ± 8.6, 134.9 ± 8.8, and 138.0 ± 8.4 s (p = 0.001)). Systolic blood pressure and mean arterial pressure were greater during the cold trial with no mask (15% and 13%, respectively), and heart rate was 10 bpm less during the third rest or recovery period during cold, no mask compared to the heat and moisture exchange mask and room temperature trials. Subjects demonstrated significant decreases in vital capacity and peak expiratory flow rate during the cold with no mask applied during the rest periods. These negative responses to cold exposure were alleviated by the use of a heat and moisture exchange mask worn during the rest intervals by minimizing cold-induced temperature stress on the respiratory system with subsequent maintenance of cardiovascular function.

Observation of the human body thermoregulation and extraction of its vein signature using NIR and MWIR imaging

NASA Astrophysics Data System (ADS)

Bouzida, Nabila; Bendada, Abdelhakim; Maldague, Xavier P.

2009-05-01

The article aims first to present a new study on the thermal regulatory response of the human skin surface while exposed to a cold environment. Our work has shown that when a cold stress is applied to the left hand, thermal infrared imaging (MWIR spectral band: 3-5 μm) allows a clear observation of a temperature rise on the right hand. Moreover, a frequency analysis was also carried out upon selected vein pixels of the images monitored during the same cold stress experiment. The objective was to identify the specific frequencies that could be linked to some physiological mechanisms of the human body. This kind of study could be very useful for the characterization of possible thermo-physiological pathologies. Besides thermoregulation, we also present in this article some results on the extraction of the hand vein pattern. Firstly, we show some vein extraction results obtained after image processing of the thermal images recorded in the thermal band (MWIR), then we compare this vein pattern to the signature obtained with a camera operating in the NIR spectral band (0.85-1.7 μm). This method could be used as a complementary means for finger print signatures in biometrics.

Chemostat Culture for Yeast Physiology.

PubMed

Kerr, Emily O; Dunham, Maitreya J

2017-07-05

The use of chemostat culture facilitates the careful comparison of different yeast strains growing in well-defined conditions. Variations in physiology can be measured by examining gene expression, metabolite levels, protein content, and cell morphology. In this protocol, we show how a combination of sample types can be collected during harvest from a single 20-mL chemostat in a ministat array, with special attention to coordinating the handling of the most time-sensitive sample types. © 2017 Cold Spring Harbor Laboratory Press.

Cold Temperatures Increase Cold Hardiness in the Next Generation Ophraella communa Beetles

PubMed Central

Zhou, Zhong-Shi; Rasmann, Sergio; Li, Min; Guo, Jian-Ying; Chen, Hong-Song; Wan, Fang-Hao

2013-01-01

The leaf beetle, Ophraella communa, has been introduced to control the spread of the common ragweed, Ambrosia artemisiifolia, in China. We hypothesized that the beetle, to be able to track host-range expansion into colder climates, can phenotypically adapt to cold temperatures across generations. Therefore, we questioned whether parental experience of colder temperatures increases cold tolerance of the progeny. Specifically, we studied the demography, including development, fecundity, and survival, as well as physiological traits, including supercooling point (SCP), water content, and glycerol content of O. communa progeny whose parents were maintained at different temperature regimes. Overall, the entire immature stage decreased survival of about 0.2%–4.2% when parents experienced cold temperatures compared to control individuals obtained from parents raised at room temperature. However, intrinsic capacity for increase (r), net reproductive rate (R 0) and finite rate of increase (λ) of progeny O. communa were maximum when parents experienced cold temperatures. Glycerol contents of both female and male in progeny was significantly higher when maternal and paternal adults were cold acclimated as compared to other treatments. This resulted in the supercooling point of the progeny adults being significantly lower compared to beetles emerging from parents that experienced room temperatures. These results suggest that cold hardiness of O. communa can be promoted by cold acclimation in previous generation, and it might counter-balance reduced survival in the next generation, especially when insects are tracking their host-plants into colder climates. PMID:24098666

Hidden impacts of ocean acidification to live and dead coral framework.

PubMed

Hennige, S J; Wicks, L C; Kamenos, N A; Perna, G; Findlay, H S; Roberts, J M

2015-08-22

Cold-water corals, such as Lophelia pertusa, are key habitat-forming organisms found throughout the world's oceans to 3000 m deep. The complex three-dimensional framework made by these vulnerable marine ecosystems support high biodiversity and commercially important species. Given their importance, a key question is how both the living and the dead framework will fare under projected climate change. Here, we demonstrate that over 12 months L. pertusa can physiologically acclimate to increased CO2, showing sustained net calcification. However, their new skeletal structure changes and exhibits decreased crystallographic and molecular-scale bonding organization. Although physiological acclimatization was evident, we also demonstrate that there is a negative correlation between increasing CO2 levels and breaking strength of exposed framework (approx. 20-30% weaker after 12 months), meaning the exposed bases of reefs will be less effective 'load-bearers', and will become more susceptible to bioerosion and mechanical damage by 2100. © 2015 The Authors.

Temperature during embryonic development has persistent effects on thermal acclimation capacity in zebrafish

PubMed Central

Scott, Graham R.; Johnston, Ian A.

2012-01-01

Global warming is intensifying interest in the mechanisms enabling ectothermic animals to adjust physiological performance and cope with temperature change. Here we show that embryonic temperature can have dramatic and persistent effects on thermal acclimation capacity at multiple levels of biological organization. Zebrafish embryos were incubated until hatching at control temperature (TE = 27 °C) or near the extremes for normal development (TE = 22 °C or 32 °C) and were then raised to adulthood under common conditions at 27 °C. Short-term temperature challenge affected aerobic exercise performance (Ucrit), but each TE group had reduced thermal sensitivity at its respective TE. In contrast, unexpected differences arose after long-term acclimation to 16 °C, when performance in the cold was ∼20% higher in both 32 °C and 22 °C TE groups compared with 27 °C TE controls. Differences in performance after acclimation to cold or warm (34 °C) temperatures were partially explained by variation in fiber type composition in the swimming muscle. Cold acclimation changed the abundance of 3,452 of 19,712 unique and unambiguously identified transcripts detected in the fast muscle using RNA-Seq. Principal components analysis differentiated the general transcriptional responses to cold of the 27 °C and 32 °C TE groups. Differences in expression were observed for individual genes involved in energy metabolism, angiogenesis, cell stress, muscle contraction and remodeling, and apoptosis. Therefore, thermal acclimation capacity is not fixed and can be modified by temperature during early development. Developmental plasticity may thus help some ectothermic organisms cope with the more variable temperatures that are expected under future climate-change scenarios. PMID:22891320

Salinity Effects on Strategies of Glycogen Utilization in Livers of Euryhaline Milkfish (Chanos chanos) under Hypothermal Stress

PubMed Central

Chang, Chia-Hao; Huang, Jian-Jun; Yeh, Chun-Yi; Tang, Cheng-Hao; Hwang, Lie-Yueh; Lee, Tsung-Han

2018-01-01

The fluctuation of temperature affects many physiological responses in ectothermic organisms, including feed intake, growth, reproduction, and behavior. Changes in environmental temperatures affect the acquisition of energy, whereas hepatic glycogen plays a central role in energy supply for the homeostasis of the entire body. Glycogen phosphorylase (GP), which catalyzes the rate-limiting step in glycogenolysis, is also an indicator of environmental stress. Here, we examined the effects of salinity on glycogen metabolism in milkfish livers under cold stress. A reduction of feed intake was observed in both freshwater (FW) and seawater (SW) milkfish under cold adaptation. At normal temperature (28°C), compared to the FW milkfish, the SW milkfish exhibited greater mRNA abundance of the liver isoform of GP (Ccpygl), higher GP activity, and less glycogen content in the livers. Upon hypothermal (18°C) stress, hepatic Ccpygl mRNA expression of FW milkfish surged at 3 h, declined at 6 and 12 h, increased again at 24 h, and increased significantly after 96 h. Increases in GP protein, GP activity, and the phosphorylation state and the breakdown of glycogen were also found in FW milkfish livers after 12 h of exposure at 18°C. Conversely, the Ccpygl transcript levels in SW milkfish were downregulated after 1 h of exposure at 18°C, whereas the protein abundance of GP, GP activity, and glycogen content were not significantly altered. Taken together, under 18°C cold stress, FW milkfish exhibited an acute response with the breakdown of hepatic glycogen for maintaining energy homeostasis of the entire body, whereas no change was observed in the hepatic glycogen content and GP activity of SW milkfish because of their greater tolerance to cold conditions. PMID:29483878

Salinity Effects on Strategies of Glycogen Utilization in Livers of Euryhaline Milkfish (Chanos chanos) under Hypothermal Stress.

PubMed

Chang, Chia-Hao; Huang, Jian-Jun; Yeh, Chun-Yi; Tang, Cheng-Hao; Hwang, Lie-Yueh; Lee, Tsung-Han

2018-01-01

The fluctuation of temperature affects many physiological responses in ectothermic organisms, including feed intake, growth, reproduction, and behavior. Changes in environmental temperatures affect the acquisition of energy, whereas hepatic glycogen plays a central role in energy supply for the homeostasis of the entire body. Glycogen phosphorylase (GP), which catalyzes the rate-limiting step in glycogenolysis, is also an indicator of environmental stress. Here, we examined the effects of salinity on glycogen metabolism in milkfish livers under cold stress. A reduction of feed intake was observed in both freshwater (FW) and seawater (SW) milkfish under cold adaptation. At normal temperature (28°C), compared to the FW milkfish, the SW milkfish exhibited greater mRNA abundance of the liver isoform of GP ( Ccpygl ), higher GP activity, and less glycogen content in the livers. Upon hypothermal (18°C) stress, hepatic Ccpygl mRNA expression of FW milkfish surged at 3 h, declined at 6 and 12 h, increased again at 24 h, and increased significantly after 96 h. Increases in GP protein, GP activity, and the phosphorylation state and the breakdown of glycogen were also found in FW milkfish livers after 12 h of exposure at 18°C. Conversely, the Ccpygl transcript levels in SW milkfish were downregulated after 1 h of exposure at 18°C, whereas the protein abundance of GP, GP activity, and glycogen content were not significantly altered. Taken together, under 18°C cold stress, FW milkfish exhibited an acute response with the breakdown of hepatic glycogen for maintaining energy homeostasis of the entire body, whereas no change was observed in the hepatic glycogen content and GP activity of SW milkfish because of their greater tolerance to cold conditions.

Archaeal Distribution in Moonmilk Deposits from Alpine Caves and Their Ecophysiological Potential.

PubMed

Reitschuler, Christoph; Spötl, Christoph; Hofmann, Katrin; Wagner, Andreas O; Illmer, Paul

2016-04-01

(Alpine) caves are, in general, windows into the Earth's subsurface. Frequently occurring structures in caves such as moonmilk (secondary calcite deposits) offer the opportunity to study intraterrestrial microbial communities, adapted to oligotrophic and cold conditions. This is an important research field regarding the dimensions of subsurface systems and cold regions on Earth. On a methodological level, moonmilk deposits from 11 caves in the Austrian Alps were collected aseptically and investigated using a molecular (qPCR and DGGE sequencing-based) methodology in order to study the occurrence, abundance, and diversity of the prevailing native Archaea community. Furthermore, these Archaea were enriched in complex media and studied regarding their physiology, with a media selection targeting different physiological requirements, e.g. methanogenesis and ammonia oxidation. The investigation of the environmental samples showed that all moonmilk deposits were characterized by the presence of the same few habitat-specific archaeal species, showing high abundances and constituting about 50 % of the total microbial communities. The largest fraction of these Archaea was ammonia-oxidizing Thaumarchaeota, while another abundant group was very distantly related to extremophilic Euryarchaeota (Moonmilk Archaea). The archaeal community showed a depth- and oxygen-dependent stratification. Archaea were much more abundant (around 80 %), compared to bacteria, in the actively forming surface part of moonmilk deposits, decreasing to about 5 % down to the bedrock. Via extensive cultivation efforts, it was possible to enrich the enigmatic Moonmilk Archaea and also AOA significantly above the level of bacteria. The most expedient prerequisites for cultivating Moonmilk Archaea were a cold temperature, oligotrophic conditions, short incubation times, a moonmilk surface inoculum, the application of erythromycin, and anaerobic (microaerophilic) conditions. On a physiological level, it seems that methanogenesis is of marginal importance, while ammonia oxidation and a still undiscovered metabolic pathway are vital elements in the (archaeal) moonmilk biome.

Physiological performance of the cold-water coral Dendrophyllia cornigera reveals its preference for temperate environments

NASA Astrophysics Data System (ADS)

Gori, Andrea; Reynaud, Stephanie; Orejas, Covadonga; Gili, Josep-Maria; Ferrier-Pagès, Christine

2014-09-01

Cold-water corals (CWCs) are key ecosystem engineers in deep-sea benthic communities around the world. Their distribution patterns are related to several abiotic and biotic factors, of which seawater temperature is arguably one of the most important due to its role in coral physiological processes. The CWC Dendrophyllia cornigera has the particular ability to thrive in several locations in which temperatures range from 11 to 17 °C, but to be apparently absent from most CWC reefs at temperatures constantly below 11 °C. This study thus aimed to assess the thermal tolerance of this CWC species, collected in the Mediterranean Sea at 12 °C, and grown at the three relevant temperatures of 8, 12, and 16 °C. This species displayed thermal tolerance to the large range of seawater temperatures investigated, but growth, calcification, respiration, and total organic carbon (TOC) fluxes severely decreased at 8 °C compared to the in situ temperature of 12 °C. Conversely, no significant differences in calcification, respiration, and TOC fluxes were observed between corals maintained at 12 and 16 °C, suggesting that the fitness of this CWC is higher in temperate rather than cold environments. The capacity to maintain physiological functions between 12 and 16 °C allows D. cornigera to be the most abundant CWC species in deep-sea ecosystems where temperatures are too warm for other CWC species (e.g., Canary Islands). This study also shows that not all CWC species occurring in the Mediterranean Sea (at deep-water temperatures of 12-14 °C) are currently living at their upper thermal tolerance limit.

Autonomic dysfunction in women with fibromyalgia

PubMed Central

2012-01-01

Fibromyalgia (FM) is an idiopathic disease characterized by widespread pain and a myriad of symptoms. Symptoms are diverse and include not only pain but also anxiety, depression, orthostatic intolerance, and cold intolerance. While the etiology of FM is not fully understood, data have suggested that FM may stem from dysfunction of the autonomic nervous system. This dysfunction has been reported at rest, and after a physiological stressor such as exercise. However, few studies have examined the responses during exercise. This novel approach may shed some new light on the effect of exercise in women with FM. PMID:22353700

Post-infectious persistent cough: pathogenesis and therapeutic options.

PubMed

Capristo, Carlo; Rossi, Giovanni A

2017-10-01

Post-infectious cough is a common symptom associated with common colds and/or upper respiratory tract infection. This cough is expected to last for only for few days and resolve spontaneously, whilst when persists for longer than three weeks is defined "persistent" and is associated tickling or an irritating sensation in the throat which often leads to paroxysms of coughing. Persistent post-infectious cough can cause morbidity since it may interfere with usual living. Despite the recent advances in understanding the mechanisms that regulate cough, in physiological and pathological conditions, current therapeutic options for post-infectious cough are little or only moderately effective.

Using Upper Extremity Skin Temperatures to Assess Thermal Comfort in Office Buildings in Changsha, China

PubMed Central

Wu, Zhibin; Li, Nianping; Cui, Haijiao; Peng, Jinqing; Chen, Haowen; Liu, Penglong

2017-01-01

Existing thermal comfort field studies are mainly focused on the relationship between the indoor physical environment and the thermal comfort. In numerous chamber experiments, physiological parameters were adopted to assess thermal comfort, but the experiments’ conclusions may not represent a realistic thermal environment due to the highly controlled thermal environment and few occupants. This paper focuses on determining the relationships between upper extremity skin temperatures (i.e., finger, wrist, hand and forearm) and the indoor thermal comfort. Also, the applicability of predicting thermal comfort by using upper extremity skin temperatures was explored. Field studies were performed in office buildings equipped with split air-conditioning (SAC) located in the hot summer and cold winter (HSCW) climate zone of China during the summer of 2016. Psychological responses of occupants were recorded and physical and physiological factors were measured simultaneously. Standard effective temperature (SET*) was used to incorporate the effect of humidity and air velocity on thermal comfort. The results indicate that upper extremity skin temperatures are good indicators for predicting thermal sensation, and could be used to assess the thermal comfort in terms of physiological mechanism. In addition, the neutral temperature was 24.7 °C and the upper limit for 80% acceptability was 28.2 °C in SET*. PMID:28934173

Using Upper Extremity Skin Temperatures to Assess Thermal Comfort in Office Buildings in Changsha, China.

PubMed

Wu, Zhibin; Li, Nianping; Cui, Haijiao; Peng, Jinqing; Chen, Haowen; Liu, Penglong

2017-09-21

Existing thermal comfort field studies are mainly focused on the relationship between the indoor physical environment and the thermal comfort. In numerous chamber experiments, physiological parameters were adopted to assess thermal comfort, but the experiments' conclusions may not represent a realistic thermal environment due to the highly controlled thermal environment and few occupants. This paper focuses on determining the relationships between upper extremity skin temperatures (i.e., finger, wrist, hand and forearm) and the indoor thermal comfort. Also, the applicability of predicting thermal comfort by using upper extremity skin temperatures was explored. Field studies were performed in office buildings equipped with split air-conditioning (SAC) located in the hot summer and cold winter (HSCW) climate zone of China during the summer of 2016. Psychological responses of occupants were recorded and physical and physiological factors were measured simultaneously. Standard effective temperature (SET*) was used to incorporate the effect of humidity and air velocity on thermal comfort. The results indicate that upper extremity skin temperatures are good indicators for predicting thermal sensation, and could be used to assess the thermal comfort in terms of physiological mechanism. In addition, the neutral temperature was 24.7 °C and the upper limit for 80% acceptability was 28.2 °C in SET*.

The impact of personality on the reporting of unfounded symptoms and illness.

PubMed

Feldman, P J; Cohen, S; Doyle, W J; Skoner, D P; Gwaltney, J M

1999-08-01

This study examined the role of personality in the reporting of symptoms and illness not supported by underlying pathology. After assessment of the Big Five personality factors, 276 healthy volunteers were inoculated with a common cold virus. On each of the following 5 days, objective indicators of pathology, self-reported symptoms, and self-reported illness onset were assessed. Neuroticism was directly associated with reports of unfounded (without a physiological basis) symptoms in individuals at baseline and postinoculation in those with and without colds. Neuroticism was also indirectly associated with reports of unfounded illness through reports of more symptoms. Openness to Experience was associated with reporting unfounded symptoms in those with verifiable colds, whereas Conscientiousness was associated with reporting unfounded illness in those who were not ill.

Gene expression analysis of overwintering mountain pine beetle larvae suggests multiple systems involved in overwintering stress, cold hardiness, and preparation for spring development

PubMed Central

Bonnett, Tiffany; Pitt, Caitlin; Spooner, Luke J.; Fraser, Jordie; Yuen, Macaire M.S.; Keeling, Christopher I.; Bohlmann, Jörg; Huber, Dezene P.W.

2016-01-01

Cold-induced mortality has historically been a key aspect of mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae), population control, but little is known about the molecular basis for cold tolerance in this insect. We used RNA-seq analysis to monitor gene expression patterns of mountain pine beetle larvae at four time points during their overwintering period—early-autumn, late-autumn, early-spring, and late-spring. Changing transcript profiles over the winter indicates a multipronged physiological response from larvae that is broadly characterized by gene transcripts involved in insect immune responses and detoxification during the autumn. In the spring, although transcripts associated with developmental process are present, there was no particular biological process dominating the transcriptome. PMID:27441109

Gene expression analysis of overwintering mountain pine beetle larvae suggests multiple systems involved in overwintering stress, cold hardiness, and preparation for spring development.

PubMed

Robert, Jeanne A; Bonnett, Tiffany; Pitt, Caitlin; Spooner, Luke J; Fraser, Jordie; Yuen, Macaire M S; Keeling, Christopher I; Bohlmann, Jörg; Huber, Dezene P W

2016-01-01

Cold-induced mortality has historically been a key aspect of mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae), population control, but little is known about the molecular basis for cold tolerance in this insect. We used RNA-seq analysis to monitor gene expression patterns of mountain pine beetle larvae at four time points during their overwintering period-early-autumn, late-autumn, early-spring, and late-spring. Changing transcript profiles over the winter indicates a multipronged physiological response from larvae that is broadly characterized by gene transcripts involved in insect immune responses and detoxification during the autumn. In the spring, although transcripts associated with developmental process are present, there was no particular biological process dominating the transcriptome.

Influence of Hot and Cold Environments on the Regulation of Energy Balance Following a Single Exercise Session: A Mini-Review.

PubMed

Charlot, Keyne; Faure, Cécile; Antoine-Jonville, Sophie

2017-06-10

Understanding the regulation of human food intake in response to an acute exercise session is of importance for interventions with athletes and soldiers, as well as overweight individuals. However, the influence of hot and cold environments on this crucial function for the regulation of body mass and motor performance has not been summarized. The purpose of this review was to exhaustively search the literature on the effect of ambient temperature during an exercise session on the subsequent subjective feeling of appetite, energy intake (EI) and its regulation. In the absence of stress due to environmental temperature, exercise-induced energy expenditure is not compensated by EI during an ad libitum meal following the session, probably due to decreased acylated ghrelin and increased peptide tyrosine tyrosine (PYY), glucagon-like peptide 1 (GLP-1), and pancreatic polypeptide (PP) levels. No systematic analysis has been yet made for major alterations of relative EI in cold and hot environments. However, observed eating behaviors are altered (proportion of solid/liquid food, carbohydrate/fat) and physiological regulation appears also to be altered. Anorexigenic signals, particularly PYY, appear to further increase in hot environments than in those that are thermoneutral. Ghrelin and leptin may be involved in the observed increase in EI after exercise in the cold, in parallel with increased energy expenditure. The potential influence of ambient thermal environment on eating behaviors after an exercise session should not be neglected.

Improved arterial blood oxygenation following intravenous infusion of cold supersaturated dissolved oxygen solution.

PubMed

Grady, Daniel J; Gentile, Michael A; Riggs, John H; Cheifetz, Ira M

2014-01-01

One of the primary goals of critical care medicine is to support adequate gas exchange without iatrogenic sequelae. An emerging method of delivering supplemental oxygen is intravenously rather than via the traditional inhalation route. The objective of this study was to evaluate the gas-exchange effects of infusing cold intravenous (IV) fluids containing very high partial pressures of dissolved oxygen (>760 mm Hg) in a porcine model. Juvenile swines were anesthetized and mechanically ventilated. Each animal received an infusion of cold (13 °C) Ringer's lactate solution (30 mL/kg/hour), which had been supersaturated with dissolved oxygen gas (39.7 mg/L dissolved oxygen, 992 mm Hg, 30.5 mL/L). Arterial blood gases and physiologic measurements were repeated at 15-minute intervals during a 60-minute IV infusion of the supersaturated dissolved oxygen solution. Each animal served as its own control. Five swines (12.9 ± 0.9 kg) were studied. Following the 60-minute infusion, there were significant increases in PaO2 and SaO2 (P < 0.05) and a significant decrease in PaCO2 (P < 0.05), with a corresponding normalization in arterial blood pH. Additionally, there was a significant decrease in core body temperature (P < 0.05) when compared to the baseline preinfusion state. A cold, supersaturated dissolved oxygen solution may be intravenously administered to improve arterial blood oxygenation and ventilation parameters and induce a mild therapeutic hypothermia in a porcine model.

Influence of Hot and Cold Environments on the Regulation of Energy Balance Following a Single Exercise Session: A Mini-Review

PubMed Central

Charlot, Keyne; Faure, Cécile; Antoine-Jonville, Sophie

2017-01-01

Understanding the regulation of human food intake in response to an acute exercise session is of importance for interventions with athletes and soldiers, as well as overweight individuals. However, the influence of hot and cold environments on this crucial function for the regulation of body mass and motor performance has not been summarized. The purpose of this review was to exhaustively search the literature on the effect of ambient temperature during an exercise session on the subsequent subjective feeling of appetite, energy intake (EI) and its regulation. In the absence of stress due to environmental temperature, exercise-induced energy expenditure is not compensated by EI during an ad libitum meal following the session, probably due to decreased acylated ghrelin and increased peptide tyrosine tyrosine (PYY), glucagon-like peptide 1 (GLP-1), and pancreatic polypeptide (PP) levels. No systematic analysis has been yet made for major alterations of relative EI in cold and hot environments. However, observed eating behaviors are altered (proportion of solid/liquid food, carbohydrate/fat) and physiological regulation appears also to be altered. Anorexigenic signals, particularly PYY, appear to further increase in hot environments than in those that are thermoneutral. Ghrelin and leptin may be involved in the observed increase in EI after exercise in the cold, in parallel with increased energy expenditure. The potential influence of ambient thermal environment on eating behaviors after an exercise session should not be neglected. PMID:28604591

Improved Arterial Blood Oxygenation Following Intravenous Infusion of Cold Supersaturated Dissolved Oxygen Solution

PubMed Central

Grady, Daniel J; Gentile, Michael A; Riggs, John H; Cheifetz, Ira M

2014-01-01

BACKGROUND One of the primary goals of critical care medicine is to support adequate gas exchange without iatrogenic sequelae. An emerging method of delivering supplemental oxygen is intravenously rather than via the traditional inhalation route. The objective of this study was to evaluate the gas-exchange effects of infusing cold intravenous (IV) fluids containing very high partial pressures of dissolved oxygen (>760 mm Hg) in a porcine model. METHODS Juvenile swines were anesthetized and mechanically ventilated. Each animal received an infusion of cold (13 °C) Ringer’s lactate solution (30 mL/kg/hour), which had been supersaturated with dissolved oxygen gas (39.7 mg/L dissolved oxygen, 992 mm Hg, 30.5 mL/L). Arterial blood gases and physiologic measurements were repeated at 15-minute intervals during a 60-minute IV infusion of the supersaturated dissolved oxygen solution. Each animal served as its own control. RESULTS Five swines (12.9 ± 0.9 kg) were studied. Following the 60-minute infusion, there were significant increases in PaO2 and SaO2 (P < 0.05) and a significant decrease in PaCO2 (P < 0.05), with a corresponding normalization in arterial blood pH. Additionally, there was a significant decrease in core body temperature (P < 0.05) when compared to the baseline preinfusion state. CONCLUSIONS A cold, supersaturated dissolved oxygen solution may be intravenously administered to improve arterial blood oxygenation and ventilation parameters and induce a mild therapeutic hypothermia in a porcine model. PMID:25249764

Similar post-stress metabolic trajectories in young and old flies.

PubMed

Colinet, Hervé; Renault, David

2018-02-01

Homeostenosis (i.e. decline in stress resistance and resilience with age) is a fundamental notion of the biogerontology and physiology of aging. Stressful situations typically challenge metabolic homeostasis and the capacity to recover from a stress-induced metabolic disorder might be particularly compromised in senescent individuals. In the present work, we report the effects of aging on low temperature stress tolerance and metabolic profiles in Drosophila melanogaster females of different ages. Adult flies aged 4, 16, 30 and 44days were subjected to acute and chronic cold stress, and data confirmed a strong decline in cold tolerance and resilience of old flies compared to young counterparts. Using quantitative target GC-MS analysis, we found distinct metabolic phenotypes between young (4day-old) and old (44day-old) flies, with glycolytic pathways being differentially affected between the two age groups. We also compared the robustness of metabolic homeostasis in young vs. old flies when exposed to cold stress using time-series metabolic analysis. In both age groups, we found evidence of strong alteration of metabolic profiles when flies were exposed to low temperature stress. Interestingly, the temporal metabolic trajectories during the recovery period were similar in young and old flies, despite strong differences in thermotolerance. In conclusion, metabolic signatures markedly changed with age and homeostenosis was observed in the phenotypic response to cold stress. However, these changes did not reflect in different temporal homeostatic response at metabolic level. Copyright © 2017 Elsevier Inc. All rights reserved.

Genome-wide transcriptomic analysis of response to low temperature reveals candidate genes determining divergent cold-sensitivity of maize inbred lines.

PubMed

Sobkowiak, Alicja; Jończyk, Maciej; Jarochowska, Emilia; Biecek, Przemysław; Trzcinska-Danielewicz, Joanna; Leipner, Jörg; Fronk, Jan; Sowiński, Paweł

2014-06-01

Maize, despite being thermophyllic due to its tropical origin, demonstrates high intraspecific diversity in cold-tolerance. To search for molecular mechanisms of this diversity, transcriptomic response to cold was studied in two inbred lines of contrasting cold-tolerance. Microarray analysis was followed by extensive statistical elaboration of data, literature data mining, and gene ontology-based classification. The lines used had been bred earlier specifically for determination of QTLs for cold-performance of photosynthesis. This allowed direct comparison of present transcriptomic data with the earlier QTL mapping results. Cold-treated (14 h at 8/6 °C) maize seedlings of cold-tolerant ETH-DH7 and cold-sensitive ETH-DL3 lines at V3 stage showed strong, consistent response of the third leaf transcriptome: several thousand probes showed similar, statistically significant change in both lines, while only tens responded differently in the two lines. The most striking difference between the responses of the two lines to cold was the induction of expression of ca. twenty genes encoding membrane/cell wall proteins exclusively in the cold-tolerant ETH-DH7 line. The common response comprised mainly repression of numerous genes related to photosynthesis and induction of genes related to basic biological activity: transcription, regulation of gene expression, protein phosphorylation, cell wall organization. Among the genes showing differential response, several were close to the QTL regions identified in earlier studies with the same inbred lines and associated with biometrical, physiological or biochemical parameters. These transcripts, including two apparently non-protein-coding ones, are particularly attractive candidates for future studies on mechanisms determining divergent cold-tolerance of inbred maize lines.

Long-Term Cold Acclimation Extends Survival Time at 0°C and Modifies the Metabolomic Profiles of the Larvae of the Fruit Fly Drosophila melanogaster

PubMed Central

Koštál, Vladimír; Korbelová, Jaroslava; Rozsypal, Jan; Zahradníčková, Helena; Cimlová, Jana; Tomčala, Aleš; Šimek, Petr

2011-01-01

Background Drosophila melanogaster is a chill-susceptible insect. Previous studies on this fly focused on acute direct chilling injury during cold shock and showed that lower lethal temperature (LLT, approximately −5°C) exhibits relatively low plasticity and that acclimations, both rapid cold hardening (RCH) and long-term cold acclimation, shift the LLT by only a few degrees at the maximum. Principal Findings We found that long-term cold acclimation considerably improved cold tolerance in fully grown third-instar larvae of D. melanogaster. A comparison of the larvae acclimated at constant 25°C with those acclimated at constant 15°C followed by constant 6°C for 2 d (15°C→6°C) showed that long-term cold acclimation extended the lethal time for 50% of the population (Lt50) during exposure to constant 0°C as much as 630-fold (from 0.137 h to 86.658 h). Such marked physiological plasticity in Lt50 (in contrast to LLT) suggested that chronic indirect chilling injury at 0°C differs from that caused by cold shock. Long-term cold acclimation modified the metabolomic profiles of the larvae. Accumulations of proline (up to 17.7 mM) and trehalose (up to 36.5 mM) were the two most prominent responses. In addition, restructuring of the glycerophospholipid composition of biological membranes was observed. The relative proportion of glycerophosphoethanolamines (especially those with linoleic acid at the sn-2 position) increased at the expense of glycerophosphocholines. Conclusion Third-instar larvae of D. melanogaster improved their cold tolerance in response to long-term cold acclimation and showed metabolic potential for the accumulation of proline and trehalose and for membrane restructuring. PMID:21957472

Basking behavior predicts the evolution of heat tolerance in Australian rainforest lizards.

PubMed

Muñoz, Martha M; Langham, Gary M; Brandley, Matthew C; Rosauer, Dan F; Williams, Stephen E; Moritz, Craig

2016-11-01

There is pressing urgency to understand how tropical ectotherms can behaviorally and physiologically respond to climate warming. We examine how basking behavior and thermal environment interact to influence evolutionary variation in thermal physiology of multiple species of lygosomine rainforest skinks from the Wet Tropics of northeastern Queensland, Australia (AWT). These tropical lizards are behaviorally specialized to exploit canopy or sun, and are distributed across marked thermal clines in the AWT. Using phylogenetic analyses, we demonstrate that physiological parameters are either associated with changes in local thermal habitat or to basking behavior, but not both. Cold tolerance, the optimal sprint speed, and performance breadth are primarily influenced by local thermal environment. Specifically, montane lizards are more cool tolerant, have broader performance breadths, and higher optimum sprinting temperatures than their lowland counterparts. Heat tolerance, in contrast, is strongly affected by basking behavior: there are two evolutionary optima, with basking species having considerably higher heat tolerance than shade skinks, with no effect of elevation. These distinct responses among traits indicate the multiple selective pressures and constraints that shape the evolution of thermal performance. We discuss how behavior and physiology interact to shape organisms' vulnerability and potential resilience to climate change. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Climatic variability and plant food distribution in Pleistocene Europe: Implications for Neanderthal diet and subsistence

NASA Astrophysics Data System (ADS)

Hardy, Bruce L.

2010-03-01

Contrary to their cold-adapted image, Neanderthals inhabited Pleistocene Europe during a time of great climatic fluctuation with temperatures ranging from as warm as present-day during the last interglacial to as cold as those of the last glacial maximum. Cold-adapted Neanderthals are similarly most often associated with the exploitation of large mammals who are themselves cold-adapted (mammoth, bison, reindeer, etc.). Cold, high-latitude environments are typically seen as lacking in plants generally and in plant foods in particular. Plant foods are therefore usually ignored and Neanderthals are increasingly being viewed as top carnivores who derived the vast majority of their diet from meat. Support for this hypothesis comes largely from stable isotope analysis which tracks only the protein portion of the diet. Diets high in lean meat largely fulfill micronutrient needs but can pose a problem at the macronutrient level. Lean meat can compose no more than 35% of dietary energy before a protein ceiling is reached. Exceeding the protein ceiling can have detrimental physiological effects on the individual. Neanderthals would have needed energy from alternative sources, particularly when animals are fat-depleted and lean meat intake is high. Underground storage organs (USOs) of plants offer one such source, concentrating carbohydrates and energy. USOs could also provide an important seasonal energy source since they are at their maximum energy storage in late fall/winter. Although Paleolithic sites are increasingly yielding plant remains, their presence is rare and they are often given only passing mention in Neanderthal dietary reconstructions. The complexity and number of potential wild plant foods, however, defies easy discussion. Native European wild edible plants with starchy USOs would have been potentially available throughout the Neanderthal range, even during the coldest periods of the Late Pleistocene.

Extradural cold block for selective neurostimulation of the bladder: development of a new technique.

PubMed

Schumacher, S; Bross, S; Scheepe, J R; Seif, C; Jünemann, K P; Alken, P

1999-03-01

Cryotechnique for selective block of the urethral sphincter and simultaneous activation of the bladder was developed to achieve physiological micturition during sacral anterior root stimulation (SARS). In ten foxhounds SARS of S2 was carried out while extradurally both spinal nerves S2 were cooled down from positive 25C in a stepwise fashion until a sphincter block was observed. Subsequently, SARS of S2 was performed while the pudendal nerves were cooled down from + 15C. The effects of spinal and pudendal nerve cold block on the urethral sphincter and bladder during SARS and the recovery time were monitored by urodynamic investigation. A complete cold block of the urethral sphincter during spinal nerve cooling was achieved in all cases. During pudendal nerve cooling, the sphincter was completely blocked in two, and incompletely blocked in four dogs. Cold block temperature of the spinal nerves averaged +11.7C and of the pudendal nerves +6.2C. During SARS and spinal nerve cooling, an increase in intravesical pressure up to 13 cm. water was recognized, and recovery time was on average 6.6 minutes. Intravesical pressure remained unchanged during pudendal nerve cooling, with recovery time being less than 1 minute. The cold block was always reversible. Cryotechnique is an excellent method for selective and reversible block of the urethral sphincter during SARS to avoid detrusor-sphincter-dyssynergia. The application of cryotechnique in functional electrical stimulation leads to an improvement of quality of life in para- or tetraplegic patients because of selective nerve stimulation with optimization of micturition, standing, walking and grasping and does so without the necessity of surgical dorsal root rhizotomy.

Sleep Deprivation and Exercise Tolerance.

DTIC Science & Technology

1986-01-01

thermoneutral environment) is alike unchanged by loss of sleep. 5) Seven subjects were allowed to exercise to thermal comfort in a very cold (OC, 2.5...Subjects selected identical work loads for thermal comfort , and became exhausted/miserable after similar period of exposure. Physiologi- cal response and

The contribution of transcriptomic and proteomic analysis in elucidating stress adaptation responses of Listeria monocytogenes

USDA-ARS?s Scientific Manuscript database

The foodborne transmission of Listeria monocytogenes requires physiological adaptation to various conditions, including the cold, osmotic, heat, acid, alkaline, and oxidative stresses, associated with food hygiene, processing, and preservation measures. We review the current knowledge on the molecul...

The achievement of thermal balance and its maintenance during environmental stress.

DOT National Transportation Integrated Search

1966-06-01

The paper describes in some detail the means, both physical and physiological, available to man for maintenance of thermal balance. It is also concerned with some aspects of thermal balance and performance when work is performed in hot or cold enviro...

Expression of ferritin-like protein in Listeria monocytogenes after cold and freezing stress.

PubMed

Miladi, Hanene; Soukri, Abdelaziz; Bakhrouf, Amina; Ammar, Emna

2012-11-01

The cold shock protein family consists of the transfer of the foodborne pathogen Listeria monocytogenes from 37 to 4 and -20 °C and was characterized by the sharp induction of a low molecular mass protein. This major cold shock protein ferritin-like protein (Flp) has an important role in regulation of various microbial physiological processes. Flp have a molecular mass of about 18 kDa, as observed on SDS-PAGE. The purification procedure including ammonium sulfate fractionation was used. Monospecific polyclonal antibodies raised in rabbits against the purified new Flp immunostained a single 18-kDa Flp band in extracts from different cytoplasmic proteins blotted onto nitrocellulose. A 411-bp cDNA fragment that corresponds to an internal region of an flp gene was obtained by RT-PCR. Our result indicated a surexpression of major cold shock protein and an important increase in flp mRNA amount after a downshift temperature especially at -20 °C.

Windchill index and military applications.

PubMed

Santee, William R

2002-07-01

A new Windchill Apparent Temperature (WCT) has been introduced to replace the Windchill Index (WCI) and Windchill Equivalent Temperature (WCET) used to quantify cold exposure. From the time of its introduction the WCI has been criticized on scientific grounds. Despite a history of criticism, the WCI and the derived WCET have been adopted by military and civilian organizations to characterize the hazards presented by exposure to cold environments. However, the military has specific needs that differ from those of the civilian population. Thus, additional weather products and devices, including thermoregulatory models, environmental monitors, and personal physiological status monitors, are available to supplement the revised WCT.

Nutritional strategies for football: counteracting heat, cold, high altitude, and jet lag.

PubMed

Armstrong, Lawrence E

2006-07-01

Environmental factors often influence the physical and mental performance of football players. Heat, cold, high altitude, and travel across time zones (i.e. leading to jet lag) act as stressors that alter normal physiological function, homeostasis, metabolism, and whole-body nutrient balance. Rather than accepting performance decrements as inevitable, well-informed coaches and players should plan strategies for training and competition that offset environmental challenges. Considering the strength of scientific evidence, this paper reviews recommendations regarding nutritional interventions that purportedly counterbalance dehydration, hyperthermia, hypothermia, hypoxia, acute or chronic substrate deficiencies, sleep loss, and desynchronization of internal biological clocks.

Relationship between metal levels in the vent mussel Bathymodiolus azoricus and local microhabitat chemical characteristics of Eiffel Tower (Lucky Strike)

NASA Astrophysics Data System (ADS)

Martins, Inês; Cosson, Richard P.; Riou, Virginie; Sarradin, Pierre-Marie; Sarrazin, Jozée; Santos, Ricardo S.; Colaço, Ana

2011-03-01

The turbulent mixing of hydrothermal hot fluid with cold seawater creates large chemical gradients at a small spatial scale that may induce variable physiological and biochemical adaptations within the vent fauna. The adaptation to such a variable environment by the vent mussel Bathymodiolus azoricus relies on a dual symbiosis hosted in the gills, and digestion of particulate organic matter. The surrounding environment not only provides the necessary energy sources and suspended organic particles for the vent mussel nutrition, but also potentially toxic compounds such as metals. Our main goal was to see if there is a relation between metal accumulation in mussel organs and the chemical characteristics of their close environment. Mussels were collected at six locations in a cold part of the Eiffel Tower fluid-seawater mixing zone, characterized by distinct chemical compositions. Metals (Cd, Cu, Fe and Zn) and metallothioneins were quantified in the gills and digestive gland. The physiological condition of the sampled mussels was also evaluated using tissues and gill indices. Our study indicates that the accumulation of metals in B. azoricus is related to their spatial distribution and linked to fine scale environmental conditions that influence the physiological status of the organism.

Coupling of the Models of Human Physiology and Thermal Comfort

NASA Astrophysics Data System (ADS)

Pokorny, J.; Jicha, M.

2013-04-01

A coupled model of human physiology and thermal comfort was developed in Dymola/Modelica. A coupling combines a modified Tanabe model of human physiology and thermal comfort model developed by Zhang. The Coupled model allows predicting the thermal sensation and comfort of both local and overall from local boundary conditions representing ambient and personal factors. The aim of this study was to compare prediction of the Coupled model with the Fiala model prediction and experimental data. Validation data were taken from the literature, mainly from the validation manual of software Theseus-FE [1]. In the paper validation of the model for very light physical activities (1 met) indoor environment with temperatures from 12 °C up to 48 °C is presented. The Coupled model predicts mean skin temperature for cold, neutral and warm environment well. However prediction of core temperature in cold environment is inaccurate and very affected by ambient temperature. Evaluation of thermal comfort in warm environment is supplemented by skin wettedness prediction. The Coupled model is designed for non-uniform and transient environmental conditions; it is also suitable simulation of thermal comfort in vehicles cabins. The usage of the model is limited for very light physical activities up to 1.2 met only.

Seed dormancy and germination changes of snowbed species under climate warming: the role of pre- and post-dispersal temperatures

PubMed Central

Bernareggi, Giulietta; Carbognani, Michele; Mondoni, Andrea; Petraglia, Alessandro

2016-01-01

Background and Aims Climate warming has major impacts on seed germination of several alpine species, hence on their regeneration capacity. Most studies have investigated the effects of warming after seed dispersal, and little is known about the effects a warmer parental environment may have on germination and dormancy of the seed progeny. Nevertheless, temperatures during seed development and maturation could alter the state of dormancy, affecting the timing of emergence and seedling survival. Here, the interplay between pre- and post-dispersal temperatures driving seed dormancy release and germination requirements of alpine plants were investigated. Methods Three plant species inhabiting alpine snowbeds were exposed to an artificial warming treatment (i.e. +1·5 K) and to natural conditions in the field. Seeds produced were exposed to six different periods of cold stratification (0, 2, 4, 8, 12 and 20 weeks at 0 °C), followed by four incubation temperatures (5, 10, 15 and 20 °C) for germination testing. Key Results A warmer parental environment produced either no or a significant increase in germination, depending on the duration of cold stratification, incubation temperatures and their interaction. In contrast, the speed of germination was less sensitive to changes in the parental environment. Moreover, the effects of warming appeared to be linked to the level of (physiological) seed dormancy, with deeper dormant species showing major changes in response to incubation temperatures and less dormant species in response to cold stratification periods. Conclusions Plants developed under warmer climates will produce seeds with changed germination responses to temperature and/or cold stratification, but the extent of these changes across species could be driven by seed dormancy traits. Transgenerational plastic adjustments of seed germination and dormancy shown here may result from increased seed viability, reduced primary and secondary dormancy state, or both, and may play a crucial role in future plant adaptation to climate change. PMID:27390354

Time-of-Day Effects on Metabolic and Clock-Related Adjustments to Cold.

PubMed

Machado, Frederico Sander Mansur; Zhang, Zhi; Su, Yan; de Goede, Paul; Jansen, Remi; Foppen, Ewout; Coimbra, Cândido Celso; Kalsbeek, Andries

2018-01-01

Daily cyclic changes in environmental conditions are key signals for anticipatory and adaptive adjustments of most living species, including mammals. Lower ambient temperature stimulates the thermogenic activity of brown adipose tissue (BAT) and skeletal muscle. Given that the molecular components of the endogenous biological clock interact with thermal and metabolic mechanisms directly involved in the defense of body temperature, the present study evaluated the differential homeostatic responses to a cold stimulus at distinct time-windows of the light/dark-cycle. Male Wistar rats were subjected to a single episode of 3 h cold ambient temperature (4°C) at one of 6 time-points starting at Zeitgeber Times 3, 7, 11, 15, 19, and 23. Metabolic rate, core body temperature, locomotor activity (LA), feeding, and drinking behaviors were recorded during control and cold conditions at each time-point. Immediately after the stimulus, rats were euthanized and both the soleus and BAT were collected for real-time PCR. During the light phase (i.e., inactive phase), cold exposure resulted in a slight hyperthermia ( p  < 0.001). Light phase cold exposure also increased metabolic rate and LA ( p  < 0.001). In addition, the prevalence of fat oxidative metabolism was attenuated during the inactive phase ( p  < 0.001). These metabolic changes were accompanied by time-of-day and tissue-specific changes in core clock gene expression, such as DBP ( p  < 0.0001) and REV-ERBα ( p  < 0.01) in the BAT and CLOCK ( p  < 0.05), PER2 ( p  < 0.05), CRY1 ( p  < 0.05), CRY2 ( p  < 0.01), and REV-ERBα ( p  < 0.05) in the soleus skeletal muscle. Moreover, genes involved in substrate oxidation and thermogenesis were affected in a time-of-day and tissue-specific manner by cold exposure. The time-of-day modulation of substrate mobilization and oxidation during cold exposure provides a clear example of the circadian modulation of physiological and metabolic responses. Interestingly, after cold exposure, time-of-day mostly affected circadian clock gene expression in the soleus muscle, despite comparable changes in LA over the light-dark-cycle. The current findings add further evidence for tissue-specific actions of the internal clock in different peripheral organs such as skeletal muscle and BAT.

The glutathione-dependent system of antioxidant defense is not modulated by temperature acclimation in muscle tissues from striped bass, Morone saxatilis.

PubMed

Grim, Jeffrey M; Simonik, Elizabeth A; Semones, Molly C; Kuhn, Donald E; Crockett, Elizabeth L

2013-02-01

Cold temperature generally induces an enhancement of oxidative capacities, a greater content of intracellular lipids, and a remodeling of lipids in biological membranes. These physiological responses may pose a heightened risk of lipid peroxidation (LPO), while warm temperature could result in greater risk of LPO since rates involving reactive oxygen species and LPO will be elevated. The current study examines responses of the glutathione system of antioxidant defense after temperature acclimation. We measured total glutathione (tGSH), and protein levels of GPx1, GPx4, and GST (cardiac and skeletal muscles), and enzymatic activity (skeletal muscle) of glutathione-dependent antioxidants (GPx, GPx4, and GST) in tissues from striped bass (Morone saxatilis) acclimated for six weeks to 7 °C or 25 °C. tGSH of cardiac muscle from cold-acclimated animals was 1.2-times higher than in warm-bodied counterparts, but unchanged with temperature acclimation in skeletal muscle. A second low molecular weight antioxidant, ascorbate was 1.4- and 1.5-times higher in cardiac and skeletal muscle, respectively in warm- than cold-acclimated animals. Despite 1.2-times higher oxidative capacities (as indicated by citrate synthase activity), in skeletal muscle from cold- versus warm-acclimated fish, levels and activities of antioxidant enzymes were similar between acclimation groups. Lipid peroxidation products (as indicated by TBARS), normalized to tissue wet weight, were more than 2-times higher in skeletal muscle from cold- than warm-acclimated animals, however, when normalized to phospholipid content there was no statistical difference between acclimation groups. Our results demonstrate that the physiological changes, associated with acclimation to low temperature in the eurythermal striped bass, are not accompanied by an enhanced antioxidant defense in the glutathione-dependent system. Copyright © 2012 Elsevier Inc. All rights reserved.

Cold acclimation induces distinctive changes in the chromatin state and transcript levels of COR genes in Cannabis sativa varieties with contrasting cold acclimation capacities.

PubMed

Mayer, Boris F; Ali-Benali, Mohamed Ali; Demone, Jordan; Bertrand, Annick; Charron, Jean-Benoit

2015-11-01

Little is known about the capacity of Cannabis sativa to cold-acclimate and develop freezing tolerance. This study investigates the cold acclimation (CA) capacity of nine C. sativa varieties and the underlying genetic and epigenetic responses. The varieties were divided into three groups based on their contrasting CA capacities by comparing the survival of non-acclimated and cold-acclimated plants in whole-plant freeze tests. In response to the CA treatment, all varieties accumulated soluble sugars but only the varieties with superior capacity for CA could maintain higher levels throughout the treatment. In addition, the varieties that acclimated most efficiently accumulated higher transcript levels of cold-regulated (COR) genes and genes involved in de novo DNA methylation while displaying locus- and variety-specific changes in the levels of H3K9ac, H3K27me3 and methylcytosine (MeC) during CA. Furthermore, these hardy C. sativa varieties displayed significant increases in MeC levels at COR gene loci when deacclimated, suggesting a role for locus-specific DNA methylation in deacclimation. This study uncovers the molecular mechanisms underlying CA in C. sativa and reveals higher levels of complexity regarding how genetic, epigenetic and environmental factors intertwine. © 2014 Scandinavian Plant Physiology Society.

Winter photosynthesis in red spruce (Picea rubens Sarg.): limitations, potential benefits, and risks

Treesearch

P.G. Schaberg

2000-01-01

Numerous cold-induced changes in physiology limit the capacity of northern conifers to photosynthesize during winter. Studies of red spruce (Picea rubens Sarg.) have shown that rates of field photosynthesis (Pfield) and laboratory measurements of photosynthetic capacity (Pmax) generally parallel seasonal...

Gene discovery using massively parallel pyrosequencing to develop ESTs for the flesh fly Sarcophaga crassipalpis

USDA-ARS?s Scientific Manuscript database

Flesh flies in the genus Sarcophaga are important models for investigating endocrinology, diapause, cold hardiness, reproduction, and immunity. Despite the prominence of Sarcophaga flesh flies as models for insect physiology and biochemistry, and in forensic studies, little genomic or transcriptom...

ROLE OF ENVIRONMENTAL HEAT AND COLD STRESS ON THE PHYSIOLOGICAL RESPONSE TO ORGANOPHOSPHATES AND OTHER TOXICANTS.

EPA Science Inventory

Most toxicological and pharmacological studies are performed in laboratory rodents maintained under comfortable environmental conditions. However, exposure to toxicants as well as some drugs can occur under stressful conditions during rest or while exercising. Heat stress can exa...

Spatio-temporal analysis of blood perfusion by imaging photoplethysmography

NASA Astrophysics Data System (ADS)

Zaunseder, Sebastian; Trumpp, Alexander; Ernst, Hannes; Förster, Michael; Malberg, Hagen

2018-02-01

Imaging photoplethysmography (iPPG) has attracted much attention over the last years. The vast majority of works focuses on methods to reliably extract the heart rate from videos. Only a few works addressed iPPGs ability to exploit spatio-temporal perfusion pattern to derive further diagnostic statements. This work directs at the spatio-temporal analysis of blood perfusion from videos. We present a novel algorithm that bases on the two-dimensional representation of the blood pulsation (perfusion map). The basic idea behind the proposed algorithm consists of a pairwise estimation of time delays between photoplethysmographic signals of spatially separated regions. The probabilistic approach yields a parameter denoted as perfusion speed. We compare the perfusion speed versus two parameters, which assess the strength of blood pulsation (perfusion strength and signal to noise ratio). Preliminary results using video data with different physiological stimuli (cold pressure test, cold face test) show that all measures are influenced by those stimuli (some of them with statistical certainty). The perfusion speed turned out to be more sensitive than the other measures in some cases. However, our results also show that the intraindividual stability and interindividual comparability of all used measures remain critical points. This work proves the general feasibility of employing the perfusion speed as novel iPPG quantity. Future studies will address open points like the handling of ballistocardiographic effects and will try to deepen the understanding of the predominant physiological mechanisms and their relation to the algorithmic performance.

Cold water immersion enhances recovery of submaximal muscle function after resistance exercise.

PubMed

Roberts, Llion A; Nosaka, Kazunori; Coombes, Jeff S; Peake, Jonathan M

2014-10-15

We investigated the effect of cold water immersion (CWI) on the recovery of muscle function and physiological responses after high-intensity resistance exercise. Using a randomized, cross-over design, 10 physically active men performed high-intensity resistance exercise followed by one of two recovery interventions: 1) 10 min of CWI at 10°C or 2) 10 min of active recovery (low-intensity cycling). After the recovery interventions, maximal muscle function was assessed after 2 and 4 h by measuring jump height and isometric squat strength. Submaximal muscle function was assessed after 6 h by measuring the average load lifted during 6 sets of 10 squats at 80% of 1 repetition maximum. Intramuscular temperature (1 cm) was also recorded, and venous blood samples were analyzed for markers of metabolism, vasoconstriction, and muscle damage. CWI did not enhance recovery of maximal muscle function. However, during the final three sets of the submaximal muscle function test, participants lifted a greater load (P < 0.05, Cohen's effect size: 1.3, 38%) after CWI compared with active recovery. During CWI, muscle temperature decreased ∼7°C below postexercise values and remained below preexercise values for another 35 min. Venous blood O2 saturation decreased below preexercise values for 1.5 h after CWI. Serum endothelin-1 concentration did not change after CWI, whereas it decreased after active recovery. Plasma myoglobin concentration was lower, whereas plasma IL-6 concentration was higher after CWI compared with active recovery. These results suggest that CWI after resistance exercise allows athletes to complete more work during subsequent training sessions, which could enhance long-term training adaptations. Copyright © 2014 the American Physiological Society.

Products of lipid peroxidation, but not membrane susceptibility to oxidative damage, are conserved in skeletal muscle following temperature acclimation.

PubMed

Grim, Jeffrey M; Semones, Molly C; Kuhn, Donald E; Kriska, Tamas; Keszler, Agnes; Crockett, Elizabeth L

2015-03-01

Changes in oxidative capacities and phospholipid remodeling accompany temperature acclimation in ectothermic animals. Both responses may alter redox status and membrane susceptibility to lipid peroxidation (LPO). We tested the hypothesis that phospholipid remodeling is sufficient to offset temperature-driven rates of LPO and, thus, membrane susceptibility to LPO is conserved. We also predicted that the content of LPO products is maintained over a range of physiological temperatures. To assess LPO susceptibility, rates of LPO were quantified with the fluorescent probe C11-BODIPY in mitochondria and sarcoplasmic reticulum from oxidative and glycolytic muscle of striped bass (Morone saxatilis) acclimated to 7°C and 25°C. We also measured phospholipid compositions, contents of LPO products [i.e., individual classes of phospholipid hydroperoxides (PLOOH)], and two membrane antioxidants. Despite phospholipid headgroup and acyl chain remodeling, these alterations do not counter the effect of temperature on LPO rates (i.e., LPO rates are generally not different among acclimation groups when normalized to phospholipid content and compared at a common temperature). Although absolute levels of PLOOH are higher in muscles from cold- than warm-acclimated fish, this difference is lost when PLOOH levels are normalized to total phospholipid. Contents of vitamin E and two homologs of ubiquinone are more than four times higher in mitochondria prepared from oxidative muscle of warm- than cold-acclimated fish. Collectively, our data demonstrate that although phospholipid remodeling does not provide a means for offsetting thermal effects on rates of LPO, differences in phospholipid quantity ensure a constant proportion of LPO products with temperature variation. Copyright © 2015 the American Physiological Society.

Impacts of extreme winter warming events on plant physiology in a sub-Arctic heath community.

PubMed

Bokhorst, Stef; Bjerke, Jarle W; Davey, Matthew P; Taulavuori, Kari; Taulavuori, Erja; Laine, Kari; Callaghan, Terry V; Phoenix, Gareth K

2010-10-01

Insulation provided by snow cover and tolerance of freezing by physiological acclimation allows Arctic plants to survive cold winter temperatures. However, both the protection mechanisms may be lost with winter climate change, especially during extreme winter warming events where loss of snow cover from snow melt results in exposure of plants to warm temperatures and then returning extreme cold in the absence of insulating snow. These events cause considerable damage to Arctic plants, but physiological responses behind such damage remain unknown. Here, we report simulations of extreme winter warming events using infrared heating lamps and soil warming cables in a sub-Arctic heathland. During these events, we measured maximum quantum yield of photosystem II (PSII), photosynthesis, respiration, bud swelling and associated bud carbohydrate changes and lipid peroxidation to identify physiological responses during and after the winter warming events in three dwarf shrub species: Empetrum hermaphroditum, Vaccinium vitis-idaea and Vaccinium myrtillus. Winter warming increased maximum quantum yield of PSII, and photosynthesis was initiated for E. hermaphroditum and V. vitis-idaea. Bud swelling, bud carbohydrate decreases and lipid peroxidation were largest for E. hermaphroditum, whereas V. myrtillus and V. vitis-idaea showed no or less strong responses. Increased physiological activity and bud swelling suggest that sub-Arctic plants can initiate spring-like development in response to a short winter warming event. Lipid peroxidation suggests that plants experience increased winter stress. The observed differences between species in physiological responses are broadly consistent with interspecific differences in damage seen in previous studies, with E. hermaphroditum and V. myrtillus tending to be most sensitive. This suggests that initiation of spring-like development may be a major driver in the damage caused by winter warming events that are predicted to become more frequent in some regions of the Arctic and that may ultimately drive plant community shifts. Copyright © Physiologia Plantarum 2010.

Conserved and narrow temperature limits in alpine insects: Thermal tolerance and supercooling points of the ice-crawlers, Grylloblatta (Insecta: Grylloblattodea: Grylloblattidae).

PubMed

Schoville, Sean D; Slatyer, Rachel A; Bergdahl, James C; Valdez, Glenda A

2015-07-01

For many terrestrial species, habitat associations and range size are dependent on physiological limits, which in turn may influence large-scale patterns of species diversity. The temperature range experienced by individuals is considered to shape the breadth of the thermal niche, with species occupying temporally and/or geographically stable climates tolerating a narrow temperature range. High-elevation environments experience large temperature fluctuations, with frequent periods below 0 °C, but Grylloblatta (Grylloblattodea: Grylloblattidae) occupy climatically stable microhabitats within this region. Here we test critical thermal limits and supercooling points for five Grylloblatta populations from across a large geographic area, to examine whether the stable microhabitats of this group are associated with a narrow thermal niche and assess their capacity to tolerate cold conditions. Thermal limits are highly conserved in Grylloblatta, despite substantial genetic divergence among populations spanning 1500 m elevation and being separated by over 500 km. Further, Grylloblatta show exceptionally narrow thermal limits compared to other insect taxa with little capacity to improve cold tolerance via plasticity. In contrast, upper thermal limits were significantly depressed by cold acclimation. Grylloblatta maintain coordinated movement until they freeze, and they die upon freezing. Convergence of the critical thermal minima, supercooling point and lower lethal limits point to adaptation to a cold but, importantly, constant thermal environment. These physiological data provide an explanation for the high endemism and patchy distribution of Grylloblatta, which relies on subterranean retreats to accommodate narrow thermal limits. These retreats are currently buffered from temperature fluctuations by snow cover, and a declining snowpack thus places Grylloblatta at risk of exposure to temperatures beyond its tolerance capacity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cold Exposure and Sleep in the Rat: REM Sleep Homeostasis and Body Size

PubMed Central

Amici, Roberto; Cerri, Matteo; Ocampo-Garcés, Adrian; Baracchi, Francesca; Dentico, Daniela; Jones, Christine Ann; Luppi, Marco; Perez, Emanuele; Parmeggiani, Pier Luigi; Zamboni, Giovanni

2008-01-01

Study Objectives: Exposure to low ambient temperature (Ta) depresses REM sleep (REMS) occurrence. In this study, both short and long-term homeostatic aspects of REMS regulation were analyzed during cold exposure and during subsequent recovery at Ta 24°C. Design: EEG activity, hypothalamic temperature, and motor activity were studied during a 24-h exposure to Tas ranging from 10°C to −10°C and for 4 days during recovery. Setting: Laboratory of Physiological Regulation during the Wake-Sleep Cycle, Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna. Subjects: 24 male albino rats. Interventions: Animals were implanted with electrodes for EEG recording and a thermistor to measure hypothalamic temperature. Measurements and Results: REMS occurrence decreased proportionally with cold exposure, but a fast compensatory REMS rebound occurred during the first day of recovery when the previous loss went beyond a “fast rebound” threshold corresponding to 22% of the daily REMS need. A slow REMS rebound apparently allowed the animals to fully restore the previous REMS loss during the following 3 days of recovery. Conclusion: Comparing the present data on rats with data from earlier studies on cats and humans, it appears that small mammals have less tolerance for REMS loss than large ones. In small mammals, this low tolerance may be responsible on a short-term basis for the shorter wake-sleep cycle, and on long-term basis, for the higher percentage of REMS that is quickly recovered following REMS deprivation. Citation: Amici R; Cerri M; Ocampo-Garcés A; Baracchi F; Dentico D; Jones CA; Luppi M; Perez E; Parmeggiani PL; Zamboni G. Cold exposure and sleep in the rat: REM sleep homeostasis and body size. SLEEP 2008;31(5):708–715. PMID:18517040

[Resuscitation of vital activity after cold arrest of respiration by physiological methods without rewarming the body].

PubMed

Ivanov, K P

2014-01-01

The arrest of respiration during deep hypothermia means death, though at a low temperature the heart may rhythmically contract for 30-40 minutes more. The attempts of rewarming only shorten the time before the heart arrest. Calcium ions (Ca2+) are believed to accumulate in the nervous cells in cold. An excess of these ions inhibits the metabolism. Moreover it stimulates the cell proteases, which destroy the cell membranes. The aim of the study was to make the the attempts to develop the methods of stimulating the respiration and heart without rewarming the body. The work was carried out on wite rats 250-320g in weight. We introduced disodium salt of ethylenediaminetetraacetic acid into the animals. The second method of blocking the mechanisms of the cold death was artificial respiration. Ethylenediaminetetraacetic acid reacts with calcium ions, decreases their quantity in the blood, and, consequently, in a complex manner in the cell protoplasm. Artificial respiration not only increases the flow of oxygen into an organism but also decreases the lowest temperature threshold of the cold death of an organism. A decrease in the surviving threshold by 1.5-1.8 degrees C is very important from the point of view of reanimation of an organism since to preserve life in the critical period of reanimation each 0.5 degrees C are important. Prolongation of minimal frequency of heart contractions and maintaining a minimal arterial blood pressure in an overcooled organism given the body temperature of 11-12.5 degrees C is a special problem of great interest associated with many physiological and biological parameters.

Mammal-like muscles power swimming in a cold-water shark.

PubMed

Bernal, Diego; Donley, Jeanine M; Shadwick, Robert E; Syme, Douglas A

2005-10-27

Effects of temperature on muscle contraction and powering movement are profound, outwardly obvious, and of great consequence to survival. To cope with the effects of environmental temperature fluctuations, endothermic birds and mammals maintain a relatively warm and constant body temperature, whereas most fishes and other vertebrates are ectothermic and conform to their thermal niche, compromising performance at colder temperatures. However, within the fishes the tunas and lamnid sharks deviate from the ectothermic strategy, maintaining elevated core body temperatures that presumably confer physiological advantages for their roles as fast and continuously swimming pelagic predators. Here we show that the salmon shark, a lamnid inhabiting cold, north Pacific waters, has become so specialized for endothermy that its red, aerobic, locomotor muscles, which power continuous swimming, seem mammal-like, functioning only within a markedly elevated temperature range (20-30 degrees C). These muscles are ineffectual if exposed to the cool water temperatures, and when warmed even 10 degrees C above ambient they still produce only 25-50% of the power produced at 26 degrees C. In contrast, the white muscles, powering burst swimming, do not show such a marked thermal dependence and work well across a wide range of temperatures.

Dull Brains and Frozen Feet: A Historical Essay on Cold.

PubMed

Lankford, Harvey V

2016-12-01

This essay will review historical and medical aspects of cold exposure, hypothermia, and frostbite during the Napoleonic era. The 19th century writings of Dominique Jean Larrey, Pierre Jean Moricheau-Beaupré, and others are used to provide an evocative supporting narrative to illustrate some of the cold illnesses, physiology, and theory of both an earlier era and the present time. Medical care for over a century followed the how but not the why of treating frostbite and hypothermia slowly with snow or cold water rather than heat. There were 2 main reasons: First was a practical attempt to limit gangrene. Less known, and long forgotten, is a major rationale based on the erroneous theory of heat called "the caloric." Because of these 2 reasons, the slow method of "cold warming" remained standard medical practice well into the 20th century. Although these recommendations are now known to be flawed, some of the reasons behind them will be discussed, along with early but correct observations on afterdrop and circumrescue collapse. There is a long backstory of treatment from 1812 to the present. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Quantification and assessment of heat and cold waves in Novi Sad, Northern Serbia

NASA Astrophysics Data System (ADS)

Basarin, Biljana; Lukić, Tin; Matzarakis, Andreas

2016-01-01

Physiologically equivalent temperature (PET) has been applied to the analysis of heat and cold waves and human thermal conditions in Novi Sad, Serbia. A series of daily minimum and maximum air temperature, relative humidity, wind, and cloud cover was used to calculate PET for the investigated period 1949-2012. The heat and cold wave analysis was carried out on days with PET values exceeding defined thresholds. Additionally, the acclimatization approach was introduced to evaluate human adaptation to interannual thermal perception. Trend analysis has revealed the presence of increasing trend in summer PET anomalies, number of days above defined threshold, number of heat waves, and average duration of heat waves per year since 1981. Moreover, winter PET anomaly as well as the number of days below certain threshold and number of cold waves per year until 1980 was decreasing, but the decrease was not statistically significant. The highest number of heat waves during summer was registered in the last two decades, but also in the first decade of the investigated period. On the other hand, the number of cold waves during six decades is quite similar and the differences are very small.

Quantification and assessment of heat and cold waves in Novi Sad, Northern Serbia.

PubMed

Basarin, Biljana; Lukić, Tin; Matzarakis, Andreas

2016-01-01

Physiologically equivalent temperature (PET) has been applied to the analysis of heat and cold waves and human thermal conditions in Novi Sad, Serbia. A series of daily minimum and maximum air temperature, relative humidity, wind, and cloud cover was used to calculate PET for the investigated period 1949-2012. The heat and cold wave analysis was carried out on days with PET values exceeding defined thresholds. Additionally, the acclimatization approach was introduced to evaluate human adaptation to interannual thermal perception. Trend analysis has revealed the presence of increasing trend in summer PET anomalies, number of days above defined threshold, number of heat waves, and average duration of heat waves per year since 1981. Moreover, winter PET anomaly as well as the number of days below certain threshold and number of cold waves per year until 1980 was decreasing, but the decrease was not statistically significant. The highest number of heat waves during summer was registered in the last two decades, but also in the first decade of the investigated period. On the other hand, the number of cold waves during six decades is quite similar and the differences are very small.

A metabolic profile for ‘Honeycrisp’ apple soggy breakdown, a chilling induced physiological disorder

USDA-ARS?s Scientific Manuscript database

‘Honeycrisp’ is an economically important apple cultivar increasing rapidly in planted acreage in many apple growing regions. Long-term cold storage can enhance value by enabling a longer window of availability, but the cultivar is highly susceptible to chilling induced disorders. Soggy breakdown ...

The role of depressed metabolism in increased radio resistance

NASA Technical Reports Server (NTRS)

Musacchia, X. J.

1972-01-01

Studies are presented of the physiology of depressed metabolism, radio-resistance in depressed metabolic states, comparative aspects of depressed metabolism, and gastrointestinal responses to ionizing radiation. Specific data cover helium-cold induced hypothermia in white rats and hamsters, and radiation responses and intestinal absorption in the gerbil.

Differential Modulation of Photosynthesis, Signaling, and Transcriptional Regulation between Tolerant and Sensitive Tomato Genotypes under Cold Stress

PubMed Central

Zhang, Junhong; Wang, Taotao; Li, Hanxia; Zhang, Yuyang; Yu, Chuying; Ye, Zhibiao

2012-01-01

The wild species Solanum habrochaites is more cold tolerant than the cultivated tomato (S. lycopersicum). To explore the mechanisms underlying cold tolerance of S. habrochaites, seedlings of S. habrochaites LA1777 introgression lines (ILs), as well as the two parents, were evaluated under low temperature (4°C). The IL LA3969 and its donor parent LA1777 were found to be more cold tolerant than the recurrent parent S. lycopersicum LA4024. The differences in physiology and global gene expression between cold-tolerant (LA1777 and LA3969) and -sensitive (LA4024) genotypes under cold stress were further investigated. Comparative transcriptome analysis identified 1613, 1456, and 1523 cold-responsive genes in LA1777, LA3969, and LA4024, respectively. Gene ontology (GO) term enrichment analysis revealed that more GO biological process terms were significantly enriched among the up-regulated genes in the two tolerant genotypes, whereas more biological processes were significantly repressed by cold stress in the sensitive one. A total of 92 genes with significant differential expression between tolerant and sensitive genotypes under cold stress were identified. Among these, many stress-related GO terms were significantly enriched, such as ‘response to stimulus’ and ‘response to stress’. Moreover, GO terms ‘response to hormone stimulus’, ‘response to reactive oxygen species (ROS)’, and ‘calcium-mediated signaling’ were also overrepresented. Several transcripts involved in hormone or ROS homeostasis were also differentially expressed. ROS, hormones, and calcium as signaling molecules may play important roles in regulating gene expression in response to cold stress. Moreover, the expression of various transcription factors, post-translational proteins, metabolic enzymes, and photosynthesis-related genes was also specifically modulated. These specific modifications may play pivotal roles in conferring cold tolerance in tomato. These results not only provide new insights into the molecular mechanisms of cold tolerance in tomato, but also provide potential candidate genes for genetic improvement. PMID:23226384

Body temperature regulation in diabetes

PubMed Central

Kenny, Glen P.; Sigal, Ronald J.; McGinn, Ryan

2016-01-01

ABSTRACT The effects of type 1 and type 2 diabetes on the body's physiological response to thermal stress is a relatively new topic in research. Diabetes tends to place individuals at greater risk for heat-related illness during heat waves and physical activity due to an impaired capacity to dissipate heat. Specifically, individuals with diabetes have been reported to have lower skin blood flow and sweating responses during heat exposure and this can have important consequences on cardiovascular regulation and glycemic control. Those who are particularly vulnerable include individuals with poor glycemic control and who are affected by diabetes-related complications. On the other hand, good glycemic control and maintenance of aerobic fitness can often delay the diabetes-related complications and possibly the impairments in heat loss. Despite this, it is alarming to note the lack of information regarding diabetes and heat stress given the vulnerability of this population. In contrast, few studies have examined the effects of cold exposure on individuals with diabetes with the exception of its therapeutic potential, particularly for type 2 diabetes. This review summarizes the current state of knowledge regarding the impact of diabetes on heat and cold exposure with respect to the core temperature regulation, cardiovascular adjustments and glycemic control while also considering the beneficial effects of maintaining aerobic fitness. PMID:27227101

Mole-rats from higher altitudes have greater thermoregulatory capabilities.

PubMed

Broekman, Marna; Bennett, Nigel C; Jackson, Craig R; Scantlebury, Michael

2006-12-30

Subterranean mammals (those that live and forage underground) inhabit a challenging microenvironment, with high levels of carbon dioxide and low levels of oxygen. Consequently, they have evolved specialised morphological and physiological adaptations. For small mammals that inhabit high altitudes, the effects of cold are compounded by low oxygen partial pressures. Hence, subterranean mammals living at high altitudes are faced with a uniquely demanding physiological environment, which presumably necessitates additional physiological adjustments. We examined the thermoregulatory capabilities of two populations of Lesotho mole-rat Cryptomys hottentotus mahali that inhabit a 'low' (1600 m) and a 'high' (3200 m) altitude. Mole-rats from the high altitude had a lower temperature of the lower critical point, a broader thermoneutral zone, a lower thermal conductance and greater regulatory non-shivering thermogenesis than animals from the lower altitude. However, minimum resting metabolic rate values were not significantly different between the populations and were low compared with allometric predictions. We suggest that thermoregulatory costs may in part be met by animals maintaining a low resting metabolic rate. High-altitude animals may adjust to their cooler, more oxygen-deficient environment by having an increased non-shivering thermogenesis whilst maintaining low thermal conductance.

Calcification is not the Achilles' heel of cold-water corals in an acidifying ocean.

PubMed

Rodolfo-Metalpa, Riccardo; Montagna, Paolo; Aliani, Stefano; Borghini, Mireno; Canese, Simonepietro; Hall-Spencer, Jason M; Foggo, Andy; Milazzo, Marco; Taviani, Marco; Houlbrèque, Fanny

2015-06-01

Ocean acidification is thought to be a major threat to coral reefs: laboratory evidence and CO2 seep research has shown adverse effects on many coral species, although a few are resilient. There are concerns that cold-water corals are even more vulnerable as they live in areas where aragonite saturation (Ωara ) is lower than in the tropics and is falling rapidly due to CO2 emissions. Here, we provide laboratory evidence that net (gross calcification minus dissolution) and gross calcification rates of three common cold-water corals, Caryophyllia smithii, Dendrophyllia cornigera, and Desmophyllum dianthus, are not affected by pCO2 levels expected for 2100 (pCO2  1058 μatm, Ωara 1.29), and nor are the rates of skeletal dissolution in D. dianthus. We transplanted D. dianthus to 350 m depth (pHT 8.02; pCO2  448 μatm, Ωara 2.58) and to a 3 m depth CO2 seep in oligotrophic waters (pHT 7.35; pCO2  2879 μatm, Ωara 0.76) and found that the transplants calcified at the same rates regardless of the pCO2 confirming their resilience to acidification, but at significantly lower rates than corals that were fed in aquaria. Our combination of field and laboratory evidence suggests that ocean acidification will not disrupt cold-water coral calcification although falling aragonite levels may affect other organismal physiological and/or reef community processes. © 2015 John Wiley & Sons Ltd.

Stressful Presentations: Mild Cold Stress in Laboratory Mice Influences Phenotype of Dendritic Cells in Naïve and Tumor-Bearing Mice

PubMed Central

Kokolus, Kathleen M.; Spangler, Haley M.; Povinelli, Benjamin J.; Farren, Matthew R.; Lee, Kelvin P.; Repasky, Elizabeth A.

2013-01-01

The ability of dendritic cells (DCs) to stimulate and regulate T cells is critical to effective anti-tumor immunity. Therefore, it is important to fully recognize any inherent factors which may influence DC function under experimental conditions, especially in laboratory mice since they are used so heavily to model immune responses. The goals of this report are to 1) briefly summarize previous work revealing how DCs respond to various forms of physiological stress and 2) to present new data highlighting the potential for chronic mild cold stress inherent to mice housed at the required standard ambient temperatures to influence baseline DCs properties in naïve and tumor-bearing mice. As recent data from our group shows that CD8+ T cell function is significantly altered by chronic mild cold stress and since DC function is crucial for CD8+ T cell activation, we wondered whether housing temperature may also be influencing DC function. Here we report that there are several significant phenotypical and functional differences among DC subsets in naïve and tumor-bearing mice housed at either standard housing temperature or at a thermoneutral ambient temperature, which significantly reduces the extent of cold stress. The new data presented here strongly suggests that, by itself, the housing temperature of mice can affect fundamental properties and functions of DCs. Therefore differences in basal levels of stress due to housing should be taken into consideration when interpreting experiments designed to evaluate the impact of additional variables, including other stressors on DC function. PMID:24575090

Stressful presentations: mild cold stress in laboratory mice influences phenotype of dendritic cells in naïve and tumor-bearing mice.

PubMed

Kokolus, Kathleen M; Spangler, Haley M; Povinelli, Benjamin J; Farren, Matthew R; Lee, Kelvin P; Repasky, Elizabeth A

2014-01-01

The ability of dendritic cells (DCs) to stimulate and regulate T cells is critical to effective anti-tumor immunity. Therefore, it is important to fully recognize any inherent factors which may influence DC function under experimental conditions, especially in laboratory mice since they are used so heavily to model immune responses. The goals of this report are to 1) briefly summarize previous work revealing how DCs respond to various forms of physiological stress and 2) to present new data highlighting the potential for chronic mild cold stress inherent to mice housed at the required standard ambient temperatures to influence baseline DCs properties in naïve and tumor-bearing mice. As recent data from our group shows that CD8(+) T cell function is significantly altered by chronic mild cold stress and since DC function is crucial for CD8(+) T cell activation, we wondered whether housing temperature may also be influencing DC function. Here we report that there are several significant phenotypical and functional differences among DC subsets in naïve and tumor-bearing mice housed at either standard housing temperature or at a thermoneutral ambient temperature, which significantly reduces the extent of cold stress. The new data presented here strongly suggests that, by itself, the housing temperature of mice can affect fundamental properties and functions of DCs. Therefore differences in basal levels of stress due to housing should be taken into consideration when interpreting experiments designed to evaluate the impact of additional variables, including other stressors on DC function.

Divergence in Eco-Physiological Responses to Drought Mirrors the Distinct Distribution of Chamerion angustifolium Cytotypes in the Himalaya–Hengduan Mountains Region

PubMed Central

Guo, Wen; Yang, Jie; Sun, Xu-Dong; Chen, Guang-Jie; Yang, Yong-Ping; Duan, Yuan-Wen

2016-01-01

Polyploid species generally occupy harsher habitats (characterized by cold, drought and/or high altitude) than diploids, but the converse was observed for Chamerion angustifolium, in which diploid plants generally inhabit higher altitudes than their polyploid derivatives. Plants at high altitudes may experience cold-induced water stress, and we therefore examined the physiological responses of diploid and hexaploid C. angustifolium to water stress to better understand the ecological differentiation of plants with different ploidy levels. We conducted a common garden experiment by subjecting seedlings of different ploidy levels to low, moderate, and severe water stress. Fourteen indicators of physiological fitness were measured, and the anatomical characteristics of the leaves of each cytotype were determined. Both cytotypes were influenced by drought, and diploids exhibited higher fitness in terms of constant root:shoot ratio (R:S ratio) and maximum quantum yield of PS II (Fv/Fm), less reduced maximal photosynthetic rate (Amax), transpiration rate (E), intercellular CO2 concentration (Ci) and stomatal conductance (gs), and higher long-term water use efficiency (WUEL) under severe water stress than did hexaploids. Analysis of leaf anatomy revealed morphological adjustments for tolerating water deficiency in diploids, in the form of closely packed mesophyll cells and small conduits in the midvein. Our results indicate that diploid C. angustifolium is more tolerant of drought than hexaploid plants, ensuring the successful survival of the diploid at high altitudes. This eco-physiological divergence may facilitate the species with different cytotypes to colonize new and large geographic ranges with heterogeneous environmental conditions. PMID:27630654

Transcriptome responses to heat- and cold-stress in ladybirds (Cryptolaemus montrouzieri Mulasnt) analyzed by deep-sequencing.

PubMed

Zhang, Yuhong; Wu, Hongsheng; Xie, Jiaqin; Jiang, Ruixin; Deng, Congshuang; Pang, Hong

2015-11-19

Changed temperature not only threaten agricultural production, but they also affect individual biological behavior, population and community of many insects, and consequently reduce the stability of our ecosystem. Insect's ability to respond to temperature stress evolved through a complex adaptive process, thus resulting in varied temperature tolerance among different insects. Both high and low extreme temperatures are detrimental to insect development since they constitute an important abiotic stress capable of inducing abnormal biological responses. Many studies on heat or cold tolerance of ladybirds have focused on measurements of physiological and biochemical indexes such as supercooling point, higher/lower lethal temperatures, survival rate, dry body weight, water content, and developmental duration. And studies of the molecular mechanisms of ladybird responses to heat or cold stress have focused on single genes, such as those encoding heat shock proteins, but has not been analyzed by transcriptome profiling. In this study, we report the use of Digital Gene Expression (DGE) tag profiling to gain insight into transcriptional events associated with heat- and cold-stress in C. montrouzieri. About 6 million tags (49 bp in length) were sequenced in a heat stress group, a cold stress group and a negative control group. We obtained 687 and 573 genes that showed significantly altered expression levels following heat and cold shock treatments, respectively. Analysis of the global gene expression pattern suggested that 42 enzyme-encoding genes mapped to many Gene Ontology terms are associated with insect's response to heat- and cold-stress. These results provide a global assessment of genes and molecular mechanisms involved in heat and cold tolerance.

Quantitative sensory studies in complex regional pain syndrome type 1/RSD.

PubMed

Tahmoush, A J; Schwartzman, R J; Hopp, J L; Grothusen, J R

2000-12-01

Patients with complex regional pain syndrome type I (CRPSD1) may have thermal allodynia after application of a non-noxious thermal stimulus to the affected limb. We measured the warm, cold, heat-evoked pain threshold and the cold-evoked pain threshold in the affected area of 16 control patients and patients with complex regional pain syndrome type 1/RSD to test the hypothesis that allodynia results from an abnormality in sensory physiology. A contact thermode was used to apply a constant 1 degrees C/second increasing (warm and heat-evoked pain) or decreasing (cold and cold-evoked pain) thermal stimulus until the patient pressed the response button to show that a temperature change was felt by the patient. Student t test was used to compare thresholds in patients and control patients. The cold-evoked pain threshold in patients with CRPSD1/RSD (p <0.001) was significantly decreased when compared with the thresholds in control patients (i.e., a smaller decrease in temperature was necessary to elicit cold-pain in patients with CRPSD1/RSD than in control patients). The heat-evoked pain threshold in patients with CRPS1/RSD was (p <0.05) decreased significantly when compared with thresholds in control patients. The warm- and cold-detection thresholds in patients with CRPS1/RSD were similar to the thresholds in control patients. This study suggests that thermal allodynia in patients with CRPS1/RSD results from decreased cold-evoked and heat-evoked pain thresholds. The thermal pain thresholds are reset (decreased) so that non-noxious thermal stimuli are perceived to be pain (allodynia).

A Basic Helix-Loop-Helix Transcription Factor, PtrbHLH, of Poncirus trifoliata Confers Cold Tolerance and Modulates Peroxidase-Mediated Scavenging of Hydrogen Peroxide1[C][W

PubMed Central

Huang, Xiao-San; Wang, Wei; Zhang, Qian; Liu, Ji-Hong

2013-01-01

The basic helix-loop-helix (bHLH) transcription factors are involved in a variety of physiological processes. However, plant bHLHs functioning in cold tolerance and the underlying mechanisms remain poorly understood. Here, we report the identification and functional characterization of PtrbHLH isolated from trifoliate orange (Poncirus trifoliata). The transcript levels of PtrbHLH were up-regulated under various abiotic stresses, particularly cold. PtrbHLH was localized in the nucleus with transactivation activity. Overexpression of PtrbHLH in tobacco (Nicotiana tabacum) or lemon (Citrus limon) conferred enhanced tolerance to cold under chilling or freezing temperatures, whereas down-regulation of PtrbHLH in trifoliate orange by RNA interference (RNAi) resulted in elevated cold sensitivity. A range of stress-responsive genes was up-regulated or down-regulated in the transgenic lemon. Of special note, several peroxidase (POD) genes were induced after cold treatment. Compared with the wild type, POD activity was increased in the overexpression plants but decreased in the RNAi plants, which was inversely correlated with the hydrogen peroxide (H2O2) levels in the tested lines. Treatment of the transgenic tobacco plants with POD inhibitors elevated the H2O2 levels and greatly compromised their cold tolerance, while exogenous replenishment of POD enhanced cold tolerance of the RNAi line. In addition, transgenic tobacco and lemon plants were more tolerant to oxidative stresses. Yeast one-hybrid assay and transient expression analysis demonstrated that PtrbHLH could bind to the E-box elements in the promoter region of a POD gene. Taken together, these results demonstrate that PtrbHLH plays an important role in cold tolerance, at least in part, by positively regulating POD-mediated reactive oxygen species removal. PMID:23624854

Do mitochondrial properties explain intraspecific variation in thermal tolerance?

PubMed

Fangue, Nann A; Richards, Jeffrey G; Schulte, Patricia M

2009-02-01

As global temperatures rise, there is a growing need to understand the physiological mechanisms that determine an organism's thermal niche. Here, we test the hypothesis that increases in mitochondrial capacity with cold acclimation and adaptation are associated with decreases in thermal tolerance using two subspecies of killifish (Fundulus heteroclitus) that differ in thermal niche. We assessed whole-organism metabolic rate, mitochondrial amount and mitochondrial function in killifish acclimated to several temperatures. Mitochondrial enzyme activities and mRNA levels were greater in fish from the northern subspecies, particularly in cold-acclimated fish, suggesting that the putatively cold-adapted northern subspecies has a greater capacity for increases in mitochondrial amount in response to cold acclimation. When tested at the fish's acclimation temperature, maximum ADP-stimulated (State III) rates of mitochondrial oxygen consumption in vitro were greater in cold-acclimated northern fish than in southern fish but did not differ between subspecies at higher acclimation temperatures. Whole-organism metabolic rate was greater in fish of the northern subspecies at all acclimation temperatures. Cold acclimation also changed the response of mitochondrial respiration to acute temperature challenge. Mitochondrial oxygen consumption was greater in cold-acclimated northern fish than in southern fish at low test temperatures, but the opposite was true at high test temperatures. These differences were reflected in whole-organism oxygen consumption. Our data indicate that the plasticity of mitochondrial function and amount differs between killifish subspecies, with the less high-temperature tolerant, and putatively cold adapted, northern subspecies having greater ability to increase mitochondrial capacity in the cold. However, there were few differences in mitochondrial properties between subspecies at warm acclimation temperatures, despite differences in both whole-organism oxygen consumption and thermal tolerance at these temperatures.

Low temperature tolerance, cold hardening and acclimation in tadpoles of the neotropical túngara frog (Engystomops pustulosus).

PubMed

Vo, Pacific; Gridi-Papp, Marcos

2017-05-01

Many frogs from temperate climates can tolerate low temperatures and increase their thermal tolerance through hardening and acclimation. Most tropical frogs, on the other hand, fail to acclimate to low temperatures. This lack of acclimation ability is potentially due to lack of selection pressure for acclimation because cold weather is less common in the tropics. We tested the generality of this pattern by characterizing the critical temperature minimum (CTMin), hardening, and acclimation responses of túngara frogs (Engystomops pustulosus). These frogs belong to a family with unknown thermal ecology. They are found in a tropical habitat with a highly constant temperature regime. The CTMin of the tadpoles was on average 12.5°C. Pre-metamorphic tadpoles hardened by 1.18°C, while metamorphic tadpoles hardened by 0.36°C. When raised at 21°C, tadpoles acclimated expanding their cold tolerance by 1.3°C in relation to larvae raised at 28°C. These results indicate that the túngara frog has a greatly reduced cold tolerance when compared to species from temperate climates, but it responds to cold temperatures with hardening and acclimation comparable to those of temperate-zone species. Cold tolerance increased with body length but cold hardening was more extensive in pre-metamorphic tadpoles than in metamorphic ones. This study shows that lack of acclimation ability is not general to the physiology of tropical anurans. Copyright © 2017 Elsevier Ltd. All rights reserved.

Overwintering biology and limits of cold tolerance in larvae of pistachio twig borer, Kermania pistaciella.

PubMed

Mollaei, M; Izadi, H; Šimek, P; Koštál, V

2016-08-01

Pistachio twig borer, Kermania pistaciella is an important pest of pistachio trees. It has an univoltine life-cycle and its larvae tunnel and feed inside pistachio twigs for almost 10 months each year. The last larval instars overwinter inside the twigs. Survival/mortality associated with low temperatures during overwintering stage is currently unknown. We found that overwintering larvae of the Rafsanjan (Iran) population of K. pistaciella rely on maintaining a stably high supercooling capacity throughout the cold season. Their supercooling points (SCPs) ranged between -19.4 and -22.7°C from October to February. Larvae were able to survive 24 h exposures to -15°C anytime during the cold season. During December and January, larvae were undergoing quiescence type of dormancy caused probably by low ambient temperatures and/or changes in host tree physiology (tree dormancy). Larvae attain highest cold tolerance (high survival at -20°C) during dormancy, which offers them sufficient protection against geographically and ecologically relevant cold spells. High cold tolerance during dormancy was not associated with accumulation of any low-molecular mass cryoprotective substances. The SCP sets the limit of cold tolerance in pistachio twig borer, meaning that high mortality of overwintering populations can be expected only in the regions or years where or when the temperatures fall below the average larval SCP (i.e., below -20°C). Partial mortality can be expected also when temperatures repeatedly drop close to the SCP on a diurnal basis.

Characterization of cold-associated microRNAs in the freeze-tolerant gall fly Eurosta solidaginis using high-throughput sequencing.

PubMed

Lyons, Pierre J; Govaere, Louise; Crapoulet, Nicolas; Storey, Kenneth B; Morin, Pier Jr

2016-12-01

Significant physiological and biochemical changes are observed in freeze-tolerant insects when confronted with cold temperatures. These insects have adapted to winter by retreating into a hypometabolic state of diapause and implementing cryoprotective mechanisms that allow them to survive whole body freezing. MicroRNAs (miRNAs), a family of short ribonucleic acids, are emerging as likely molecular players underlying the process of cold adaptation. Unfortunately, the data is sparse concerning the signature of miRNAs that are modulated following cold exposure in the freeze-tolerant goldenrod gall fly Eurosta solidaginis. Leveraging for the first time a next-generation sequencing approach, differentially expressed miRNAs were evaluated in 5°C and -15°C-exposed E. solidaginis larvae. Next-generation sequencing expression data was subsequently validated by qRT-PCR for selected miRNA targets. Results demonstrate 24 differentially expressed freeze-responsive miRNAs. Notable, miR-1-3p, a miRNA modulated at low temperature in another cold-hardy insect, and miR-14-3p, a miRNA associated with stress response in the fruit fly, were shown to be significantly up-regulated in -15°C-exposed larvae. Overall, this work identifies, for the first time in a high-throughput manner, differentially expressed miRNAs in cold-exposed E. solidaginis larvae and further clarifies an emerging signature of miRNAs modulated at low temperatures in cold-hardy insects. Copyright © 2016 Elsevier Inc. All rights reserved.

Identification of Proteins Using iTRAQ and Virus-Induced Gene Silencing Reveals Three Bread Wheat Proteins Involved in the Response to Combined Osmotic-Cold Stress.

PubMed

Zhang, Ning; Zhang, Lingran; Shi, Chaonan; Zhao, Lei; Cui, Dangqun; Chen, Feng

2018-05-25

Crops are often subjected to a combination of stresses in the field. To date, studies on the physiological and molecular responses of common wheat to a combination of osmotic and cold stresses, however, remain unknown. In this study, wheat seedlings exposed to osmotic-cold stress for 24 h showed inhibited growth, as well as increased lipid peroxidation, relative electrolyte leakage, and soluble sugar contents. iTRAQ-based quantitative proteome method was employed to determine the proteomic profiles of the roots and leaves of wheat seedlings exposed to osmotic-cold stress conditions. A total of 250 and 258 proteins with significantly altered abundance in the roots and leaves were identified, respectively, and the majority of these proteins displayed differential abundance, thereby revealing organ-specific differences in adaptation to osmotic-cold stress. Yeast two hybrid assay examined five pairs of stress/defense-related protein-protein interactions in the predicted protein interaction network. Furthermore, quantitative real-time PCR analysis indicated that abiotic stresses increased the expression of three candidate protein genes, i.e., TaGRP2, CDCP, and Wcor410c in wheat leaves. Virus-induced gene silencing indicated that three genes TaGRP2, CDCP, and Wcor410c were involved in modulating osmotic-cold stress in common wheat. Our study provides useful information for the elucidation of molecular and genetics bases of osmotic-cold combined stress in bread wheat.

Adaptation to seasonality and the winter freeze

PubMed Central

Preston, Jill C.; Sandve, Simen R.

2013-01-01

Flowering plants initially diversified during the Mesozoic era at least 140 million years ago in regions of the world where temperate seasonal environments were not encountered. Since then several cooling events resulted in the contraction of warm and wet environments and the establishment of novel temperate zones in both hemispheres. In response, less than half of modern angiosperm families have members that evolved specific adaptations to cold seasonal climates, including cold acclimation, freezing tolerance, endodormancy, and vernalization responsiveness. Despite compelling evidence for multiple independent origins, the level of genetic constraint on the evolution of adaptations to seasonal cold is not well understood. However, the recent increase in molecular genetic studies examining the response of model and crop species to seasonal cold offers new insight into the evolutionary lability of these traits. This insight has major implications for our understanding of complex trait evolution, and the potential role of local adaptation in response to past and future climate change. In this review, we discuss the biochemical, morphological, and developmental basis of adaptations to seasonal cold, and synthesize recent literature on the genetic basis of these traits in a phylogenomic context. We find evidence for multiple genetic links between distinct physiological responses to cold, possibly reinforcing the coordinated expression of these traits. Furthermore, repeated recruitment of the same or similar ancestral pathways suggests that land plants might be somewhat pre-adapted to dealing with temperature stress, perhaps making inducible cold traits relatively easy to evolve. PMID:23761798

Health impact of the 2008 cold spell on mortality in subtropical China: the climate and health impact national assessment study (CHINAs)

PubMed Central

2014-01-01

Background Many studies have investigated heat wave related mortality, but less attention has been given to the health effects of cold spells in the context of global warming. The 2008 cold spell in China provided a unique opportunity to estimate the effects of the 2008 cold spell on mortality in subtropical regions, spatial heterogeneity of the effects, stratification effect and added effects caused by sustained cold days. Methods Thirty-six study communities were selected from 15 provinces in subtropical China. Daily mortality and meteorological data were collected for each community from 2006 to 2010. A distributed lag linear non-linear model (DLNM) with a lag structure of up to 27 days was used to analyze the association between the 2008 cold spell and mortality. Multivariate meta-analyses were used to combine the cold effects across each community. Results The 2008 cold spell increased mortality by 43.8% (95% CI: 34.8% ~ 53.4%) compared to non-cold spell days with the highest effects in southern and central China. The effects were more pronounced for respiratory mortality (RESP) than for cardiovascular (CVD) or cerebrovascular mortality (CBD), for females more than for males, and for the elderly aged ≥75 years old more than for younger people. Overall, 148,279 excess deaths were attributable to the 2008 cold spell. The cold effect was mainly from extreme low temperatures rather than sustained cold days during this 2008 cold spell. Conclusions The 2008 cold spell increased mortality in subtropical China, which was mainly attributable to the low temperature rather than the sustained duration of the cold spell. The cold effects were spatially heterogeneous and modified by individual-specific characteristics such as gender and age. PMID:25060645

Small unilamellar liposomes as a membrane model for cell inactivation by cold atmospheric plasma treatment

NASA Astrophysics Data System (ADS)

Maheux, S.; Frache, G.; Thomann, J. S.; Clément, F.; Penny, C.; Belmonte, T.; Duday, D.

2016-09-01

Cold atmospheric plasma is thought to be a promising tool for numerous biomedical applications due to its ability to generate a large diversity of reactive species in a controlled way. In some cases, it can also generate pulsed electric fields at the zone of treatment, which can induce processes such as electroporation in cell membranes. However, the interaction of these reactive species and the pulse electric field with cells in a physiological medium is very complex, and we still need a better understanding in order to be useful for future applications. A way to reach this goal is to work with model cell membranes such as liposomes, with the simplest physiological liquid and in a controlled atmosphere in order to limit the number of parallel reactions and processes. In this paper, where this approach has been chosen, 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) small unilamellar vesicles (SUV) have been synthesized in a phosphate buffered aqueous solution, and this solution has been treated by a nanosecond pulsed plasma jet under a pure nitrogen atmosphere. It is only the composition of the plasma gas that has been changed in order to generate different cocktails of reactive species. After the quantification of the main plasma reactive species in the phosphate buffered saline (PBS) solution, structural, surface charge state, and chemical modifications generated on the plasma treated liposomes, due to the interaction with the plasma reactive species, have been carefully characterized. These results allow us to further understand the effect of plasma reactive species on model cell membranes in physiological liquids. The permeation through the liposomal membrane and the reaction of plasma reactive species with molecules encapsulated inside the liposomes have also been evaluated. New processes of degradation are finally presented and discussed, which come from the specific conditions of plasma treatment under the pure nitrogen atmosphere.

The impact of cold spells on mortality and effect modification by cold spell characteristics

NASA Astrophysics Data System (ADS)

Wang, Lijun; Liu, Tao; Hu, Mengjue; Zeng, Weilin; Zhang, Yonghui; Rutherford, Shannon; Lin, Hualiang; Xiao, Jianpeng; Yin, Peng; Liu, Jiangmei; Chu, Cordia; Tong, Shilu; Ma, Wenjun; Zhou, Maigeng

2016-12-01

In China, the health impact of cold weather has received little attention, which limits our understanding of the health impacts of climate change. We collected daily mortality and meteorological data in 66 communities across China from 2006 to 2011. Within each community, we estimated the effect of cold spell exposure on mortality using a Distributed Lag Nonlinear Model (DLNM). We also examined the modification effect of cold spell characteristics (intensity, duration, and timing) and individual-specific factors (causes of death, age, gender and education). Meta-analysis method was finally used to estimate the overall effects. The overall cumulative excess risk (CER) of non-accidental mortality during cold spell days was 28.2% (95% CI: 21.4%, 35.3%) compared with non-cold spell days. There was a significant increase in mortality when the cold spell duration and intensity increased or occurred earlier in the season. Cold spell effects and effect modification by cold spell characteristics were more pronounced in south China. The elderly, people with low education level and those with respiratory diseases were generally more vulnerable to cold spells. Cold spells statistically significantly increase mortality risk in China, with greater effects in southern China. This effect is modified by cold spell characteristics and individual-level factors.

Cold adaptation mechanisms in the ghost moth Hepialus xiaojinensis: Metabolic regulation and thermal compensation.

PubMed

Zhu, Wei; Zhang, Huan; Li, Xuan; Meng, Qian; Shu, Ruihao; Wang, Menglong; Zhou, Guiling; Wang, Hongtuo; Miao, Lin; Zhang, Jihong; Qin, Qilian

2016-02-01

Ghost moths (Lepidoptera: Hepialidae) are cold-adapted stenothermal species inhabiting alpine meadows on the Tibetan Plateau. They have an optimal developmental temperature of 12-16 °C but can maintain feeding and growth at 0 °C. Their survival strategies have received little attention, but these insects are a promising model for environmental adaptation. Here, biochemical adaptations and energy metabolism in response to cold were investigated in larvae of the ghost moth Hepialus xiaojinensis. Metabolic rate and respiratory quotient decreased dramatically with decreasing temperature (15-4 °C), suggesting that the energy metabolism of ghost moths, especially glycometabolism, was sensitive to cold. However, the metabolic rate at 4 °C increased with the duration of cold exposure, indicating thermal compensation to sustain energy budgets under cold conditions. Underlying regulation strategies were studied by analyzing metabolic differences between cold-acclimated (4 °C for 48 h) and control larvae (15 °C). In cold-acclimated larvae, the energy generating pathways of carbohydrates, instead of the overall consumption of carbohydrates, was compensated in the fat body by improving the transcription of related enzymes. The mobilization of lipids was also promoted, with higher diacylglycerol, monoacylglycerol and free fatty acid content in hemolymph. These results indicated that cold acclimation induced a reorganization on metabolic structure to prioritise energy metabolism. Within the aerobic process, flux throughout the tricarboxylic acid (TCA) cycle was encouraged in the fat body, and the activity of α-ketoglutarate dehydrogenase was the likely compensation target. Increased mitochondrial cristae density was observed in the midgut of cold-acclimated larvae. The thermal compensation strategies in this ghost moth span the entire process of energy metabolism, including degration of metabolic substrate, TCA cycle and oxidative phosphorylation, and from an energy budget perspective explains how ghost moths sustain physiological activity in cold environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

Control of flowering time and cold response by a NAC-domain protein in Arabidopsis.

PubMed

Yoo, So Yeon; Kim, Yunhee; Kim, Soo Young; Lee, Jong Seob; Ahn, Ji Hoon

2007-07-25

Plants must integrate complex signals from environmental and endogenous cues to fine-tune the timing of flowering. Low temperature is one of the most common environmental stresses that affect flowering time; however, molecular mechanisms underlying the cold temperature regulation of flowering time are not fully understood. We report the identification of a novel regulator, LONG VEGETATIVE PHASE 1 (LOV1), that controls flowering time and cold response. An Arabidopsis mutant, longvegetative phase 1-1D (lov1-1D) showing the late-flowering phenotype, was isolated by activation tagging screening. Subsequent analyses demonstrated that the phenotype of the mutant resulted from the overexpression of a NAC-domain protein gene (At2g02450). Both gain- and loss-of-function alleles of LOV1 affected flowering time predominantly under long-day but not short-day conditions, suggesting that LOV1 may act within the photoperiod pathway. The expression of CONSTANS (CO), a floral promoter, was affected by LOV1 level, suggesting that LOV1 controls flowering time by negatively regulating CO expression. The epistatic relationship between CO and LOV1 was consistent with this proposed regulatory pathway. Physiological analyses to elucidate upstream signalling pathways revealed that LOV1 regulates the cold response in plants. Loss of LOV1 function resulted in hypersensitivity to cold temperature, whereas a gain-of-function allele conferred cold tolerance. The freezing tolerance was accompanied by upregulation of cold response genes, COLD-REGULATED 15A (COR15A) and COLD INDUCED 1 (KIN1) without affecting expression of the C-repeat-binding factor/dehydration responsive element-binding factor 1 (CBF/DREB1) family of genes. Our study shows that LOV1 functions as a floral repressor that negatively regulates CO expression under long-day conditions and acts as a common regulator of two intersecting pathways that regulate flowering time and the cold response, respectively. Our results suggest an overlapping pathway for controlling cold stress response and flowering time in plants.

Effects of reduced winter duration on seed dormancy and germination in six populations of the alpine herb Aciphyllya glacialis (Apiaceae)

PubMed Central

Hoyle, G. L.; Cordiner, H.; Good, R. B.; Nicotra, A. B.

2014-01-01

The life stages of seed germination and seedling establishment play a vital role in maintaining plant populations and determining range dynamics of species. Thus, it is not surprising that specific germination requirements and dormancy mechanisms have evolved in all major angiosperm clades. In a rapidly changing climate, we face growing pressure to manage, conserve and restore native plant species and communities. To achieve these aims, we require solid knowledge of whether and how seed germination requirements and dormancy status vary between different populations of a given species and how germination strategies may be affected by warming climatic conditions. We assessed the effect of decreasing durations of cold stratification (i.e. conditions representing a shortened winter as predicted under climate change) on germination and dormancy of the alpine herb Aciphylla glacialis. Our results confirmed previous research showing that A. glacialis seeds possess physiological dormancy that can be alleviated by cold stratification. In addition, the results demonstrated that A. glacialis seeds have underdeveloped embryos at dispersal; these grow to germinable size following 4–9 weeks at both constant 5°C and 10–5°C (day–night) temperatures. We conclude that A. glacialis exhibits morphophysiological dormancy. Furthermore, we found that the final percentage germination and dormancy status varied significantly among natural populations and that this variation did not correlate with elevation at the site of seed origin. Seeds germinated following 6–8 weeks of cold stratification, and seedlings showed no detrimental effects as a result of shorter stratification periods. Together, these results suggest that reduced duration of winter is unlikely to have direct negative impacts on germination or early seedling growth in A. glacialis. The causes and implications of the population variation in germination traits are discussed. PMID:27293636

Neuromuscular function during knee extension exercise after cold water immersion.

PubMed

Wakabayashi, Hitoshi; Wijayanto, Titis; Tochihara, Yutaka

2017-06-23

Human adaptability to cold environment has been focused on in the physiological anthropology and related research area. Concerning the human acclimatization process in the natural climate, it is necessary to conduct a research assessing comprehensive effect of cold environment and physical activities in cold. This study investigated the effect of cold water immersion on the exercise performance and neuromuscular function during maximal and submaximal isometric knee extension. Nine healthy males participated in this study. They performed maximal and submaximal (20, 40, and 60% maximal load) isometric knee extension pre- and post-immersion in 23, 26, and 34 °C water. The muscle activity of the rectus femoris (RF) and vastus lateralis (VL) was measured using surface electromyography (EMG). The percentages of the maximum voluntary contraction (%MVC) and mean power frequency (MPF) of EMG data were analyzed. The post-immersion maximal force was significantly lower in 23 °C than in 26 and 34 °C conditions (P < 0.05). The post-immersion %MVC of RF was significantly higher than pre-immersion during 60% maximal exercise in 23 and 26 °C conditions (P < 0.05). In the VL, the post-immersion %MVC was significantly higher than pre-immersion in 23 and 26 °C conditions during 20% maximal exercise and in 26 °C at 40 and 60% maximal intensities (P < 0.05). The post-immersion %MVC of VL was significantly higher in 26 °C than in 34 °C at 20 and 60% maximal load (P < 0.05). The post-immersion MPF of RF during 20% maximal intensity was significantly lower in 23 °C than in 26 and 34 °C conditions (P < 0.05), and significantly different between three water temperature conditions at 40 and 60% maximal intensities (P < 0.05). The post-immersion MPF of VL during three submaximal trials were significantly lower in 23 and 26 °C than in 34 °C conditions (P < 0.05). The lower shift of EMG frequency would be connected with the decrease in the nerve and muscle fibers conduction velocity. To compensate for the impairment of each muscle fibers function, more muscle fibers might be recruited to maintain the working load. This might result in the greater amplitude of EMG after the cold immersion.

Braving the attitude of altitude: Caragana jubata at work in cold desert of Himalaya

PubMed Central

Bhardwaj, Pardeep Kumar; Kapoor, Ritu; Mala, Deep; Bhagwat, Geetika; Acharya, Vishal; Singh, Anil Kumar; Vats, Surender Kumar; Ahuja, Paramvir Singh; Kumar, Sanjay

2013-01-01

The present work was conducted to understand the basis of adaptation in Caragana jubata in its niche environment at high altitude cold desert of Himalaya. Molecular data showed predominance of genes encoding chaperones and those involved in growth and development at low temperature (LT), a major cue operative at high altitude. Importantly, these genes expressed in C. jubata in its natural habitat. Their homologues in Arabidopsis thaliana, Oryza sativa, and Glycine max did not exhibit similar trend of gene expression at LT. Constitutive expression and a quick up-regulation of the above genes suggested the ability of C. jubata to adjust its cellular machinery to maintain growth and development in its niche. This was reflected in LT50 (the temperature at which 50% injury occurred) and LT mediated photosynthetic acclimatory response. Such molecular and physiological plasticity enables C. jubata to thrive in the high altitude cold desert of Himalayas. PMID:23289064

[How to efficiently conduct a physiological examination of a child--from the viewpoint of a medical technologist].

PubMed

Yamadera, Yukio; Aihara, Rieko; Koitabashi, Yoshie; Matsuda, Mitsuko; Takakuda, Yoshie; Kurosaki, Sachiko

2014-08-01

Children are often frightened, cry, refuse to sit still, and may not cooperate during a physiological examination. Technologists must take considerable care to reduce the child's anxiety. Specifically, we should use creative solutions, start by interacting with the patient, using dolls or toys, and explain the procedure to him/her in a friendly way, communicating more effectively with the patient's family. When performing the actual examinations, technologists need to work skillfully with a complete understanding of the purpose of the examinations, having the ability to identify the changes that occur in various developmental stages and interpret the pathophysiological mechanisms specific to children. Furthermore, we must always have an awareness of safety, taking measures to prevent falls from the bed and/or to keep the room warm if examinations require the child to be naked, so that he/she will not catch a cold. I explain various points of caution and possible solutions regarding electrocardiograms, electroencephalograms, and ultrasonography, from the viewpoint of a medical technologist.

The UTCI-clothing model.

PubMed

Havenith, George; Fiala, Dusan; Błazejczyk, Krzysztof; Richards, Mark; Bröde, Peter; Holmér, Ingvar; Rintamaki, Hannu; Benshabat, Yael; Jendritzky, Gerd

2012-05-01

The Universal Thermal Climate Index (UTCI) was conceived as a thermal index covering the whole climate range from heat to cold. This would be impossible without considering clothing as the interface between the person (here, the physiological model of thermoregulation) and the environment. It was decided to develop a clothing model for this application in which the following three factors were considered: (1) typical dressing behaviour in different temperatures, as observed in the field, resulting in a model of the distribution of clothing over the different body segments in relation to the ambient temperature, (2) the changes in clothing insulation and vapour resistance caused by wind and body movement, and (3) the change in wind speed in relation to the height above ground. The outcome was a clothing model that defines in detail the effective clothing insulation and vapour resistance for each of the thermo-physiological model's body segments over a wide range of climatic conditions. This paper details this model's conception and documents its definitions.

Renal neuroendocrine control of desiccation and cold tolerance by Drosophila suzukii

PubMed Central

Alford, Lucy; Yeoh, Joseph GC; Marley, Richard; Dornan, Anthony J; Dow, Julian AT; Davies, Shireen A

2017-01-01

Abstract BACKGROUND Neuropeptides are central to the regulation of physiological and behavioural processes in insects, directly impacting cold and desiccation survival. However, little is known about the control mechanisms governing these responses in Drosophila suzukii. The close phylogenetic relationship of D. suzukii with Drosophila melanogaster allows, through genomic and functional studies, an insight into the mechanisms directing stress tolerance in D. suzukii. RESULTS Capability (Capa), leucokinin (LK), diuretic hormone 44 (DH44) and DH31 neuropeptides demonstrated a high level of conservation between D. suzukii and D. melanogaster with respect to peptide sequences, neuronal expression, receptor localisation, and diuretic function in the Malpighian tubules. Despite D. suzukii's ability to populate cold environments, it proved sensitive to both cold and desiccation. Furthermore, in D. suzukii, Capa acts as a desiccation‐ and cold stress‐responsive gene, while DH 44 gene expression is increased only after desiccation exposure, and the LK gene after nonlethal cold stress recovery. CONCLUSION This study provides a comparative investigation into stress tolerance mediation by neuroendocrine signalling in two Drosophila species, providing evidence that similar signalling pathways control fluid secretion in the Malpighian tubules. Identifying processes governing specific environmental stresses affecting D. suzukii could lead to the development of targeted integrated management strategies to control insect pest populations. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:28714258

Effect of variability in lighting and temperature environments for mature gilts housed in gestation crates on measures of reproduction and animal well-being.

PubMed

Canaday, D C; Salak-Johnson, J L; Visconti, A M; Wang, X; Bhalerao, K; Knox, R V

2013-03-01

The effects of room temperature and light intensity before breeding and into early gestation were evaluated on the reproductive performance and well-being of gilts housed individually in crates. In eight replicates, estrus was synchronized in mature gilts (n = 198) and after last feeding of Matrix were randomly assigned to a room temperature of 15°C (COLD), 21°C (NEUTRAL), or 30°C (HOT) and a light intensity of 11 (DIM) or 433 (BRIGHT) lx. Estrous detection was performed daily and gilts inseminated twice. Blood samples were collected before and after breeding for determination of immune measures and cortisol concentrations. Gilt ADFI, BW, and body temperature were measured. On d 30 postbreeding, gilts were slaughtered to recover reproductive tracts to evaluate pregnancy and litter characteristics. There were no temperature × light intensity interactions for any response variable. Reproductive measures of follicle development, expression of estrus, ovulation rate, pregnancy rate (83.2%), litter size (14.3 ± 0.5), and fetal measures were not affected by temperature or lighting (P > 0.10). Gilts in COLD (37.6°C) had a lower (P < 0.05) rectal temperature than those in NEUTRAL (38.2°C) and HOT (38.6 ± 0.04°C). Both BW gain and final BW were greater (P < 0.0001) for gilts kept in HOT than those in NEUTRAL or COLD environments. Cortisol was greater (P < 0.01) for gilts kept in COLD compared with those kept in the HOT room. Gilts housed in the HOT environment made more postural changes (P < 0.05) than did those kept in either COLD or NEUTRAL temperatures. Gilts kept in the HOT temperature spent more total time lying and more time lying ventrally compared with those gilts housed in the NEUTRAL or COLD rooms. Total white blood cells and the percentage of neutrophils as well as neutrophil-to-lymphocyte ratio were all influenced (P < 0.05) by temperature but there was no effect (P > 0.10) of light or interaction with temperature on other immune cells or measures. These results indicate that temperatures in the range of 15 to 30°C or light intensity at 11 to 433 lx do not impact reproduction during the follicular phase and into early gestation for mature gilts housed in gestation crates. However, room temperature does impact physiological, behavioral, and immune responses of mature gilts and should be considered as a potential factor that may influence gilt well-being during the first 30 d postbreeding.

[Adaptive mechanisms and behavioural recommendations: playing football in heat, cold and high altitude conditions].

PubMed

Born, D-P; Hoppe, M W; Lindner, N; Freiwald, J; Holmberg, H-C; Sperlich, B

2014-03-01

Football is played worldwide and players often have to cope with hot and cold temperatures as well as high altitude conditions. The upcoming and past world championships in Brazil, Qatar and South Africa illustrate the necessity for behavioural strategies and adaptation to extreme environmental conditions. When playing football in the heat or cold, special clothing, hydration and nutritional and acclimatisation strategies are vital for high-level performance. When playing at high altitude, the reduced oxygen partial pressure impairs endurance performance and alters the technical and tactical requirements. Special high-altitude adaptation and preparation strategies are essential for football teams based at sea-level in order to perform well and compete successfully. Therefore, the aim of the underlying review is: 1) to highlight the difficulties and needs of football teams competing in extreme environmental conditions, 2) to summarise the thermoregulatory, physiological, neuronal and psychological mechanism, and 3) to provide recommendations for coping with extreme environmental conditions in order to perform at a high level when playing football in the heat, cold and at high altitude. © Georg Thieme Verlag KG Stuttgart · New York.

Genetic and biochemical bases of superficial scald storage disorder in apple and pear fruits

USDA-ARS?s Scientific Manuscript database

Superficial scald is a physiological storage disorder affecting apple and pear fruits. The disorder develops during cold storage and intensifies after removal to market temperatures. Scald symptoms result from necrosis of a few hypodermal cell layers and manifest as brown or black patches on the fru...

Behaviorally Mediated, Warm Adaptation: A Physiological Strategy When Mice Are Allowed to Behaviorally Thermoregulate

EPA Science Inventory

Laboratory mice housed under standard vivarium conditions with an ambient temperature (Ta) of -22°C are likely to be cold stressed because this Ta is below their thermoneutral zone (TNZ). Mice raised at Tas within the TNZ adapt to the warmer temperatures, developing smaller int...

Integrating physiological threshold experiments with climate modeling to project mangrove species' range expansion.

PubMed

Cavanaugh, Kyle C; Parker, John D; Cook-Patton, Susan C; Feller, Ilka C; Williams, A Park; Kellner, James R

2015-05-01

Predictions of climate-related shifts in species ranges have largely been based on correlative models. Due to limitations of these models, there is a need for more integration of experimental approaches when studying impacts of climate change on species distributions. Here, we used controlled experiments to identify physiological thresholds that control poleward range limits of three species of mangroves found in North America. We found that all three species exhibited a threshold response to extreme cold, but freeze tolerance thresholds varied among species. From these experiments, we developed a climate metric, freeze degree days (FDD), which incorporates both the intensity and the frequency of freezes. When included in distribution models, FDD accurately predicted mangrove presence/absence. Using 28 years of satellite imagery, we linked FDD to observed changes in mangrove abundance in Florida, further exemplifying the importance of extreme cold. We then used downscaled climate projections of FDD to project that these range limits will move northward by 2.2-3.2 km yr(-1) over the next 50 years. © 2014 John Wiley & Sons Ltd.

Germination of dimorphic seeds of the desert annual halophyte Suaeda aralocaspica (Chenopodiaceae), a C4 plant without Kranz anatomy.

PubMed

Wang, Lei; Huang, Zhenying; Baskin, Carol C; Baskin, Jerry M; Dong, Ming

2008-11-01

Suaeda aralocaspica is a C4 summer annual halophyte without Kranz anatomy that is restricted to the deserts of central Asia. It produces two distinct types of seeds that differ in colour, shape and size. The primary aims of the present study were to compare the dormancy and germination characteristics of dimorphic seeds of S. aralocaspica and to develop a conceptual model of their dynamics. Temperatures simulating those in the natural habitat of S. aralocaspica were used to test for primary dormancy and germination behaviour of fresh brown and black seeds. The effects of cold stratification, gibberellic acid, seed coat scarification, seed coat removal and dry storage on dormancy breaking were tested in black seeds. Germination percentage and recovery responses of brown seeds, non-treated black seeds and 8-week cold-stratified black seeds to salt stress were tested. Brown seeds were non-dormant, whereas black seeds had non-deep Type 2 physiological dormancy (PD). Germination percentage and rate of germination of brown seeds and of variously pretreated black seeds were significantly higher than those of non-pretreated black seeds. Exposure of seeds to various salinities had significant effects on germination, germination recovery and induction into secondary dormancy. A conceptual model is presented that ties these results together and puts them into an ecological context. The two seed morphs of S. aralocaspica exhibit distinct differences in dormancy and germination characteristics. Suaeda aralocaspica is the first cold desert halophyte for which non-deep Type 2 PD has been documented.

Mannose and fructose metabolism in red blood cells during cold storage in SAGM.

PubMed

Rolfsson, Óttar; Johannsson, Freyr; Magnusdottir, Manuela; Paglia, Giuseppe; Sigurjonsson, Ólafur E; Bordbar, Aarash; Palsson, Sirus; Brynjólfsson, Sigurður; Guðmundsson, Sveinn; Palsson, Bernhard

2017-11-01

Alternate sugar metabolism during red blood cell (RBC) storage is not well understood. Here we report fructose and mannose metabolism in RBCs during cold storage in SAGM and the impact that these monosaccharides have on metabolic biomarkers of RBC storage lesion. RBCs were stored in SAGM containing uniformly labeled 13 C-fructose or 13 C-mannose at 9 or 18 mmol/L concentration for 25 days. RBCs and media were sampled at 14 time points during storage and analyzed using ultraperformance liquid chromatography-mass spectrometry. Blood banking quality assurance measurements were performed. Red blood cells incorporated fructose and mannose during cold storage in the presence of glucose. Mannose was metabolized in preference to glucose via glycolysis. Fructose lowered adenosine triphosphate (ATP) levels and contributed little to ATP maintenance when added to SAGM. Both monosaccharides form the advanced glycation end product glycerate. Mannose activates enzymes in the RBC that take part in glycan synthesis. Fructose or mannose addition to RBC SAGM concentrates may not offset the shift in metabolism of RBCs that occurs after 10 days of storage. Fructose and mannose metabolism at 4°C in SAGM reflects their metabolism at physiologic temperature. Glycerate excretion is a measure of protein deglycosylation activity in stored RBCs. No cytoprotective effect was observed upon the addition of either fructose or mannose to SAGM. © 2017 AABB.

The effect of cold priming on the fitness of Arabidopsis thaliana accessions under natural and controlled conditions.

PubMed

Cvetkovic, Jelena; Müller, Klaus; Baier, Margarete

2017-03-09

Priming improves an organism's performance upon a future stress. To test whether cold priming supports protection in spring and how it is affected by cold acclimation, we compared seven Arabidopsis accessions with different cold acclimation potentials in the field and in the greenhouse for growth, photosynthetic performance and reproductive fitness in March and May after a 14 day long cold-pretreatment at 4 °C. In the plants transferred to the field in May, the effect of the cold pretreatment on the seed yield correlated with the cold acclimation potential of the accessions. In the March transferred plants, the reproductive fitness was most supported by the cold pretreatment in the accessions with the weakest cold acclimation potential. The fitness effect was linked to long-term effects of the cold pretreatment on photosystem II activity stabilization and leaf blade expansion. The study demonstrated that cold priming stronger impacts on plant fitness than cold acclimation in spring in accessions with intermediate and low cold acclimation potential.

Interactive effects of the affect quality and directional focus of mental imagery on pain analgesia.

PubMed

Alden, A L; Dale, J A; DeGood, D E

2001-06-01

College students (25 men and 25 women) were randomly assigned (within sex) to each of the 4 factorial groups, based on manipulation of affect quality (positive vs. negative) and directional focus (internal vs. external) of mental imagery, and to a control group receiving no manipulation. Both imagery variables had a significant impact on pain tolerance and ratings during a cold-pressor test with positive affect and external imagery producing greater analgesia than their counterpart conditions. Positive affect imagery combined with external imagery resulted in the lowest reported pain amongst the groups. However, self-reported mood descriptors did not consistently parallel the pain tolerance and rating data. Likewise, although heart rate and skin potential responses increased during the cold pressor for the group as a whole, the only significant difference amongst the experimental groups was the relatively higher skin potential reactivity of the positive affect-external imagery group--possibly reflecting greater task engagement for this group. Seemingly, imagery in this situation operates primarily via cognitive, rather than via physiological mediators of the pain experience.

Two key temporally distinguishable molecular and cellular components of white adipose tissue browning during cold acclimation.

PubMed

Jankovic, Aleksandra; Golic, Igor; Markelic, Milica; Stancic, Ana; Otasevic, Vesna; Buzadzic, Biljana; Korac, Aleksandra; Korac, Bato

2015-08-01

White to brown adipose tissue conversion and thermogenesis can be ignited by different conditions or agents and its sustainability over the long term is still unclear. Browning of rat retroperitoneal white adipose tissue (rpWAT) during cold acclimation involves two temporally apparent components: (1) a predominant non-selective browning of most adipocytes and an initial sharp but transient induction of uncoupling protein 1, peroxisome proliferator-activated receptor (PPAR) coactivator-1α, PPARγ and PPARα expression, and (2) the subsistence of relatively few thermogenically competent adipocytes after 45 days of cold acclimation. The different behaviours of two rpWAT beige/brown adipocyte subsets control temporal aspects of the browning process, and thus regulation of both components may influence body weight and the potential successfulness of anti-obesity therapies. Conversion of white into brown adipose tissue may have important implications in obesity resistance and treatment. Several browning agents or conditions ignite thermogenesis in white adipose tissue (WAT). To reveal the capacity of WAT to function in a brownish/burning mode over the long term, we investigated the progression of the rat retroperitoneal WAT (rpWAT) browning during 45 days of cold acclimation. During the early stages of cold acclimation, the majority of rpWAT adipocytes underwent multilocularization and thermogenic-profile induction, as demonstrated by the presence of a multitude of uncoupling protein 1 (UCP1)-immunopositive paucilocular adipocytes containing peroxisome proliferator-activated receptor (PPAR) coactivator-1α (PGC-1α) and PR domain-containing 16 (PRDM16) in their nuclei. After 45 days, all adipocytes remained PRDM16 immunopositive, but only a few multilocular adipocytes rich in mitochondria remained UCP1/PGC-1α immunopositive. Molecular evidence showed that thermogenic recruitment of rpWAT occurred following cold exposure, but returned to starting levels after cold acclimation. Compared with controls (22 ± 1 °C), levels of UCP1 mRNA increased in parallel with PPARγ (PPARα from days 1 to 7 and PGC-1α on day 1). Transcriptional recruitment of rpWAT was followed by an increase in UCP1 protein content (from days 1 to 21). Results clearly showed that most of the adipocytes within rpWAT underwent transient brown-fat-like thermogenic recruitment upon stimulation, but only a minority of cells retained a brown adipose tissue-like phenotype after the attainment of cold acclimation. Therefore, browning of WAT is dependent on both maintaining the thermogenic response and retaining enough brown-like thermogenically competent adipocytes in the long-term. Both aspects of browning could be important for long-term energy homeostasis and body-weight regulation. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Diapause Induction, Color Change, and Cold Tolerance Physiology of the Diapausing Larvae of the Chouioia cunea (Hymenoptera: Eulophidae)

PubMed Central

Zhao, Liwei; Xu, Xiaorui; Xu, Zhe; Liu, Yanqun; Sun, Shouhui

2014-01-01

Abstract The chalcid wasp Chouioia cunea Yang (Hymenoptera: Eulophidae) is one of the most dominant pupal parasitoids of Hyphantria cunea (Drury) (Lepidoptera: Arctiidae), an invasive pest of many forestry trees and agricultural crops. For mass rearing C. cunea for biological control purposes, the pupae of Antheraea pernyi (Guérin-Méneville) (Lepidoptera: Saturniidae) have been widely used as a substitute host in China. In this article, photoperiodic effect on diapause induction in C. cunea within the pupae of A. pernyi was investigated, and the differences in cold tolerance physiology including supercooling point, water content, and activities of three protective enzymes (Peroxidase [POD], Catalase [CAT], and Superoxide dismuase [SOD]) between diapause and nondiapause mature larvae were comparatively determined. Our results revealed that C. cunea possess a short-day induced larval diapause. The critical photoperiods for diapause induction in C. cunea were estimated to be between a photoperiod of 13:11 and 14:10 (L:D) h at 18°C, or between a photoperiod of 12:12 and 13:11 (L:D) h at 21°C or 24°C. We also found that the color of C. cunea diapausing larvae was taupe, while the normally developed (nondiapausing) individuals were light yellow. This body color change can be used as an indicator of diapause entry of C. cunea larave. The average supercooling point of diapausing mature larvae were lower than those of nondiapausing ones. There were significant differences in the activity of three protective enzymes (POD, CAT, and SOD) between diapausing and nondiapausing mature larvae. PMID:25527599

Cold exposure and sleep in the rat: REM sleep homeostasis and body size.

PubMed

Amici, Roberto; Cerri, Matteo; Ocampo-Garcés, Adrian; Baracchi, Francesca; Dentico, Daniela; Jones, Christine Ann; Luppi, Marco; Perez, Emanuele; Parmeggiani, Pier Luigi; Zamboni, Giovanni

2008-05-01

Exposure to low ambient temperature (Ta) depresses REM sleep (REMS) occurrence. In this study, both short and long-term homeostatic aspects of REMS regulation were analyzed during cold exposure and during subsequent recovery at Ta 24 degrees C. EEG activity, hypothalamic temperature, and motor activity were studied during a 24-h exposure to Tas ranging from 10 degrees C to -10 degrees C and for 4 days during recovery. Laboratory of Physiological Regulation during the Wake-Sleep Cycle, Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna. 24 male albino rats. Animals were implanted with electrodes for EEG recording and a thermistor to measure hypothalamic temperature. REMS occurrence decreased proportionally with cold exposure, but a fast compensatory REMS rebound occurred during the first day of recovery when the previous loss went beyond a "fast rebound" threshold corresponding to 22% of the daily REMS need. A slow REMS rebound apparently allowed the animals to fully restore the previous REMS loss during the following 3 days of recovery. Comparing the present data on rats with data from earlier studies on cats and humans, it appears that small mammals have less tolerance for REMS loss than large ones. In small mammals, this low tolerance may be responsible on a short-term basis for the shorter wake-sleep cycle, and on long-term basis, for the higher percentage of REMS that is quickly recovered following REMS deprivation.

Physiological role of glucose-6-phosphate dehydrogenase in cold acclimation of strawberry (Fragaria × ananassa)

NASA Astrophysics Data System (ADS)

Zhang, Yong; Yu, Dingqun; Luo, Ya; Wang, Xiaorong; Chen, Qing; Sun, Bo; Wang, Yan; Liu, Zejing; Tang, Haoru

2018-04-01

In recent years, there has been an increasing interest in study of new resistance mechanism in fruit trees. All these regard the climate change and subsequent fruit production. Glucose-6-phosphate dehydrogenase (G6PDH) catalyzes the first and rate-limiting step of the oxidative pentose phosphate pathway (OPPP), and the expression of this enzyme is related to different biotic and abiotic stresses. Under accumulation of low temperature stress, the significant increase in G6PDH activity was found to be closely correlated to the levels of antioxidant enzymes, malondialdehyde (MDA) contents, sugar contents as well as changes of superoxide (O2•-). It is suggested that the enhancement of cold resistance of strawberry, which induced by cold acclimation, related to the significant increase in G6PDH activity. On one hand, G6PDH activates NADPH oxidase to generate reactive oxygen species (ROS); on the other hand, it may be involved in the activation of antioxidant enzymes, and accelerates many other important NADPH-dependent enzymatic reactions. Then further result in the elevation of membrane stability and cold resistance of strawberry. Interestingly, even though the plants were placed again under a temperature of 25°C for 1 d, the higher cold resistance, enzyme activities and soluble sugar content acquired.

The Combined Effect of Cold and Moisture on Manual Performance.

PubMed

Ray, Matthew; Sanli, Elizabeth; Brown, Robert; Ennis, Kerri Ann; Carnahan, Heather

2018-02-01

Objective The aim of this study was to investigate the combined effect of cold and moisture on manual performance and tactile sensitivity. Background People working in the ocean environment often perform manual work in cold and wet conditions. Although the independent effects of cold and moisture on hand function are known, their combined effect has not been investigated. Method Participants completed sensory (Touch-Test, two-point discrimination) and motor (Purdue Pegboard, Grooved Pegboard, reef knot untying) tests in the following conditions: dry hand, wet hand, cold hand, and cold and wet hand. Results For the Purdue Pegboard and knot untying tasks, the greatest decrement in performance was observed in the cold-and-wet-hand condition, whereas the decrements seen in the cold-hand and wet-hand conditions were similar. In the Grooved Pegboard task, the performance decrements exhibited in the cold-and-wet-hand condition and the cold-hand condition were similar, whereas no decrement was observed in the wet-hand condition. Tactile sensitivity was reduced in the cold conditions for the Touch-Test but not the two-point discrimination test. The combined effect of cold and moisture led to the largest performance decrements except when intrinsic object properties helped with grasp maintenance. The independent effects of cold and moisture on manual performance were comparable. Application Tools and equipment for use in the cold ocean environment should be designed to minimize the effects of cold and moisture on manual performance by including object properties that enhance grasp maintenance and minimize the fine-dexterity requirements.

Thermal niche for in situ seed germination by Mediterranean mountain streams: model prediction and validation for Rhamnus persicifolia seeds

PubMed Central

Porceddu, Marco; Mattana, Efisio; Pritchard, Hugh W.; Bacchetta, Gianluigi

2013-01-01

Background and Aims Mediterranean mountain species face exacting ecological conditions of rainy, cold winters and arid, hot summers, which affect seed germination phenology. In this study, a soil heat sum model was used to predict field emergence of Rhamnus persicifolia, an endemic tree species living at the edge of mountain streams of central eastern Sardinia. Methods Seeds were incubated in the light at a range of temperatures (10–25 and 25/10 °C) after different periods (up to 3 months) of cold stratification at 5 °C. Base temperatures (Tb), and thermal times for 50 % germination (θ50) were calculated. Seeds were also buried in the soil in two natural populations (Rio Correboi and Rio Olai), both underneath and outside the tree canopy, and exhumed at regular intervals. Soil temperatures were recorded using data loggers and soil heat sum (°Cd) was calculated on the basis of the estimated Tb and soil temperatures. Key Results Cold stratification released physiological dormancy (PD), increasing final germination and widening the range of germination temperatures, indicative of a Type 2 non-deep PD. Tb was reduced from 10·5 °C for non-stratified seeds to 2·7 °C for seeds cold stratified for 3 months. The best thermal time model was obtained by fitting probit germination against log °Cd. θ50 was 2·6 log °Cd for untreated seeds and 2·17–2·19 log °Cd for stratified seeds. When θ50 values were integrated with soil heat sum estimates, field emergence was predicted from March to April and confirmed through field observations. Conclusions Tb and θ50 values facilitated model development of the thermal niche for in situ germination of R. persicifolia. These experimental approaches may be applied to model the natural regeneration patterns of other species growing on Mediterranean mountain waterways and of physiologically dormant species, with overwintering cold stratification requirement and spring germination. PMID:24201139

Low ambient temperature elevates plasma triiodothyronine concentrations while reducing digesta mean retention time and methane yield in sheep.

PubMed

Barnett, M C; McFarlane, J R; Hegarty, R S

2015-06-01

Ruminant methane yield (MY) is positively correlated with mean retention time (MRT) of digesta. The hormone triiodothyronine (T3 ), which is negatively correlated with ambient temperature, is known to influence MRT. It was hypothesised that exposing sheep to low ambient temperatures would increase plasma T3 concentration and decrease MRT of digesta within the rumen of sheep, resulting in a reduction of MY. To test this hypothesis, six Merino sheep were exposed to two different ambient temperatures (cold treatment, 9 ± 1 °C; warm control 26 ± 1 °C). The effects on MY, digesta MRT, plasma T3 concentration, CO2 production, DM intake, DM digestibility, change in body weight (BW), rumen volatile fatty acid (VFA) concentrations, estimated microbial protein output, protozoa abundance, wool growth, water intake, urine output and rectal temperature were studied. Cold treatment resulted in a reduction in MY (p < 0.01); digesta MRT in rumen (p < 0.01), hindgut (p = 0.01) and total digestive tract (p < 0.01); protozoa abundance (p < 0.05); and water intake (p < 0.001). Exposure to cold temperature increased plasma T3 concentration (p < 0.05), CO2 production (p = 0.01), total VFA concentrations (p = 0.03) and estimated microbial output from the rumen (p = 0.03). The rate of wool growth increased (p < 0.01) due to cold treatment, but DM intake, DM digestibility and BW change were not affected. The results suggest that exposure of sheep to cold ambient temperatures reduces digesta retention time in the gastrointestinal tract, leading to a reduction in enteric methane yield. Further research is warranted to determine whether T3 could be used as an indirect selection tool for genetic selection of low enteric methane-producing ruminants. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.

[Low-temperature response and cold tolerance at spike differentiation stage of winter wheat varieties sowed in spring].

PubMed

Xu, Lan; Gao, Zhi-fiang; An, Wei; Yuan, Ya-qi; Li, Yan-liang

2015-06-01

A total of 10 winter wheat varieties were imported from the middle and lower reaches of the Yangtze River region in China. Those varieties were sowed in spring in Xinding basin area of Shanxi Province, and the field trials were performed for two years (2013-2014). The traits and physiological characteristics under low temperature stress including grain yield, total content of chlorophyll, osmotic adjustment, membrane system, ion leakage rate, contents of soluble sugar and soluble protein were investigated, and the cold tolerance levels of the wheat varieties were assessed. The results showed that low temperature stress led to increases in wheat leaf ion leakage rate, soluble sugar and protein contents, but obvious reduction of chlorophyll content. According to principal component analysis and cold tolerance (D value) , Yumai 10, Yangmai 20, and Yunmai 42 were classed as cold sensitive wheat varieties. Yangmai 13, Yumai 12, and Ningmai 13 were classed as stronger cold-resistant wheat genotypes, and showed stability through two-year field trials, with the D values being 0.665-0.659, 0.493-0.495, and 0.471-0.583, respectively, while the D values for the controls Ning 2038 and Xinchun 30 were 0.368-0.397, and 0.328-0.330, respectively. The grain yields of the cold resistant wheat varieties were significantly higher than that of the other varieties tested. Therefore, Yangmai 13, Yumai 12 and Ningmai 13 could be imported and used as the cold tolerant wheat varieties for North Plain of China.

Breeding for sustainable production in a changing climate – understanding the physiological basis of genetic by environmental interactions

USDA-ARS?s Scientific Manuscript database

Abiotic stresses (drought, cold, heat, excess, water, salinity) result in loses in yield and quality of crops. In addition, these stresses limit the areas that can be cultivated because of yield instability and crop loss. Global warming models predict erratic weather patterns making the impact of th...

Cold in the common garden: comparative low-temperature tolerance of boreal and temperate conifer foliage

Treesearch

G. Richard Strimbeck; Trygve D. Kjellsen; Paul G. Schaberg; Paula F. Murakami

2007-01-01

Because they maintain green foliage throughout the winter season, evergreen conifers may face special physiological challenges in a warming world. We assessed the midwinter low-temperature (LT) tolerance of foliage from eight temperate and boreal species in each of the genera Abies, Picea, and Pinus growing in an arboretum in...

The overwintering biology of the acorn weevil, Curculio glandium in southwestern Ontario.

PubMed

Udaka, Hiroko; Sinclair, Brent J

2014-08-01

The acorn weevil, Curculio glandium, is a widespread predator of acorns in eastern North America that overwinters in the soil as a larva. It is possible that low temperatures limit its northern geographic range, so we determined the cold tolerance strategy, seasonal variation in cold tolerance, and explored the physiological plasticity of overwintering larvae. Weevil larvae were collected from acorns of red and bur oak from Pelee Island, southwestern Ontario in fall 2010 and 2011. C. glandium larvae are freeze avoidant and larvae collected from bur oak acorns had lower supercooling points (SCPs: -7.6±0.36°C, LT50: -7.2°C) than those collected from red oak acorns (SCPs: -6.1±0.40°C, LT50: -6.1°C). In the winter of 2010-2011, SCPs and water content decreased, however these changes did not occur in 2011-2012, when winter soil temperatures fluctuated greatly in the absence of the buffering effect of snow. To examine whether larvae utilize cryoprotective dehydration, larvae from red oak acorns were exposed to -5°C in the presence of ice for seven days. These conditions decreased the SCP without affecting water content, suggesting that SCP and water content are not directly coupled. Finally, long-term acclimation at 0°C for six weeks slightly increased cold tolerance but also did not affect water content. Thus, although larval diet affects cold tolerance, there is limited plasticity after other treatments. The soil temperatures we observed were not close to lethal limits, although we speculate that soil temperatures in northerly habitats, or in years of reduced snow cover, has the potential to cause mortality in the field. Copyright © 2014 Elsevier Ltd. All rights reserved.

Short-term metabolic and growth responses of the cold-water coral Lophelia pertusa to ocean acidification

NASA Astrophysics Data System (ADS)

Hennige, S. J.; Wicks, L. C.; Kamenos, N. A.; Bakker, D. C. E.; Findlay, H. S.; Dumousseaud, C.; Roberts, J. M.

2014-01-01

Cold-water corals are associated with high local biodiversity, but despite their importance as ecosystem engineers, little is known about how these organisms will respond to projected ocean acidification. Since preindustrial times, average ocean pH has decreased from 8.2 to ~8.1, and predicted CO2 emissions will decrease by up to another 0.3 pH units by the end of the century. This decrease in pH may have a wide range of impacts upon marine life, and in particular upon calcifiers such as cold-water corals. Lophelia pertusa is the most widespread cold-water coral (CWC) species, frequently found in the North Atlantic. Here, we present the first short-term (21 days) data on the effects of increased CO2 (750 ppm) upon the metabolism of freshly collected L. pertusa from Mingulay Reef Complex, Scotland, for comparison with net calcification. Over 21 days, corals exposed to increased CO2 conditions had significantly lower respiration rates (11.4±1.39 SE, μmol O2 g-1 tissue dry weight h-1) than corals in control conditions (28.6±7.30 SE μmol O2 g-1 tissue dry weight h-1). There was no corresponding change in calcification rates between treatments, measured using the alkalinity anomaly technique and 14C uptake. The decrease in respiration rate and maintenance of calcification rate indicates an energetic imbalance, likely facilitated by utilisation of lipid reserves. These data from freshly collected L. pertusa from the Mingulay Reef Complex will help define the impact of ocean acidification upon the growth, physiology and structural integrity of this key reef framework forming species.

Soman toxicity during and after exposure to different environmental temperatures.

PubMed

Wheeler, T G

1989-01-01

A systematic study has been conducted to determine physiological susceptibility to the potent anticholinesterase soman during and after exposure to different environmental temperatures. Rats were placed in an environmental chamber set at -1, 7, 15, 23, or 31 degrees C (80% relative humidity, RH) from 0000 to 0800 h. Soman injections were given subcutaneously (sc) at 0600 h (during thermal stress), or at 0810 h after removal from the chamber (injected and tested at 23 degrees C, 60% RH). The measures (taken 30 min after soman injection) included core temperature, grip strength, general state of health, and LD10 estimates (taken 2 h post injection). Soman exposure produced a dose-related effect on each measure under all thermal stress conditions. During thermal stress, soman exposure produced major changes in core temperature ranging from 26 to 41 degrees C, which were linearly related to the environmental temperature condition. After removal from the chamber, soman exposure reduced core temperature by only 1 degree C without regard to prior thermal stress temperature. Grip strength and subjective health rating were soman dose-related with only a minor chamber temperature influence. The toxicity of soman was increased during exposure to either cold or hot environments and after removal from the cold environments. The adrenal-cortical stress response to cold involves increased metabolism and oxygen requirement. The exception was the decreased toxicity observed when soman exposure occurred after removal from a hot environment, exacerbated by a failure in the respiratory system due to anticholinesterase exposure. The increased toxicity of soman while in or after removal from a cold environment is believed to be due to a generalized adrenal-cortical stress response. The increased soman toxicity while in a hot environment, but decreased toxicity after removal from the hot environment, provides an interesting subject for further research.

Climate-dependent evolution of Antarctic ectotherms: An integrative analysis

NASA Astrophysics Data System (ADS)

Pörtner, Hans O.

2006-04-01

The paper explores the climate-dependent evolution of marine Antarctic fauna and tries to identify key mechanisms involved as well as the driving forces that have caused the physiological and life history characteristics observed today. In an integrative approach it uses the recent concept of oxygen and capacity limited thermal tolerance to identify potential links between molecular, cellular, whole-organism, and ecological characteristics of marine animal life in the Antarctic. As a generalized pattern, minimization of baseline energy costs, for the sake of maximized growth in the cold, appears as one over-arching principle shaping the evolution and functioning of Antarctic marine ectotherms. This conclusion is supported by recent comparisons with (sub-) Arctic ectotherms, where elevated levels of energy turnover result at unstable, including cold temperatures, and are related to wide windows of thermal tolerance and associated metabolic features. At biochemical levels, metabolic regulation at low temperatures in general, is supported by the cold compensation of enzyme kinetic parameters like substrate affinities and turnover numbers, through minute structural modifications of the enzyme molecule. These involve a shift in protein folding, sometimes supported by the replacement of individual amino acids. The hypothesis is developed that efficient metabolic regulation at low rates in Antarctic marine stenotherms occurs through high mitochondrial densities at low capacities and possibly enhanced levels of Arrhenius activation energies or activation enthalpies. This contrasts the more costly patterns of metabolic regulation at elevated rates in cold-adapted eurytherms. Energy savings in Antarctic ectotherms, largely exemplified in fish, typically involve low-cost, diffusive oxygen distribution due to high density of lipid membranes, loss of haemoglobin, myoglobin and the heat shock response, reduced anaerobic capacity, large myocytes with low ion exchange activities, and the use of lipid body stores for neutral buoyancy. Important trade-offs result from obligatory energy savings in the permanent cold: low metabolic rates support cold-compensated growth but imply narrow windows of thermal tolerance and reduced scopes for activity. The degree of thermal specialization is not uniformly defined by cold temperature but varies with life style characteristics and activity levels and associated aerobic scope. Trade-offs for the sake of cold compensated growth parallel reduced capacities for exercise performance, exacerbated by the effect of high haemolymph magnesium levels in crustaceans and, possibly, other invertebrates. High magnesium levels likely exclude the group of reptant decapod crustaceans from Antarctic waters below 0 °C. The hypothesis is developed that energy savings imposed by the permanent cold bear specific life history consequences. Due to effects of allometry, energy savings are exacerbated at small body size, favouring passive lecithotrophic larvae. At all stages of life history, reduced energy turnover for the sake of growth causes delays and low rates in other higher functions, with the result of late maturity, fecundity and offspring release, as well as extended development. As a consequence, extended life spans evolved due to life history requirements. At the same time, polar gigantism is enabled by a combination of elevated oxygen levels in cold waters, of reduced metabolism and of extended periods of growth at slow developmental rates.

Postglacial Terrestrial Carbon Dynamics and Atmospheric CO2

NASA Astrophysics Data System (ADS)

Prentice, C. I.; Harrison, S. P.; Kaplan, J. O.

2002-12-01

Combining PMIP climate model results from the last glacial maximum (LGM) with biome modelling indicates the involvement of both cold, dry climate and physiological effects of low atmospheric CO2 in reducing tree cover on the continents. Further results with the LPJ dynamic vegetation model agree with independent evidence for greatly reduced terrestrial carbon storage at LGM, and suggest that terrestrial carbon storage continued to increase during the Holocene. These results point to predominantly oceanic explanations for preindustrial changes in atmospheric CO2, although land changes after the LGM may have contributed indirectly by reducing the aeolian marine Fe source and (on a longer time scale) by triggering CaCO3 compensation in the ocean.

Seed dormancy and germination changes of snowbed species under climate warming: the role of pre- and post-dispersal temperatures.

PubMed

Bernareggi, Giulietta; Carbognani, Michele; Mondoni, Andrea; Petraglia, Alessandro

2016-09-01

Climate warming has major impacts on seed germination of several alpine species, hence on their regeneration capacity. Most studies have investigated the effects of warming after seed dispersal, and little is known about the effects a warmer parental environment may have on germination and dormancy of the seed progeny. Nevertheless, temperatures during seed development and maturation could alter the state of dormancy, affecting the timing of emergence and seedling survival. Here, the interplay between pre- and post-dispersal temperatures driving seed dormancy release and germination requirements of alpine plants were investigated. Three plant species inhabiting alpine snowbeds were exposed to an artificial warming treatment (i.e. +1·5 K) and to natural conditions in the field. Seeds produced were exposed to six different periods of cold stratification (0, 2, 4, 8, 12 and 20 weeks at 0 °C), followed by four incubation temperatures (5, 10, 15 and 20 °C) for germination testing. A warmer parental environment produced either no or a significant increase in germination, depending on the duration of cold stratification, incubation temperatures and their interaction. In contrast, the speed of germination was less sensitive to changes in the parental environment. Moreover, the effects of warming appeared to be linked to the level of (physiological) seed dormancy, with deeper dormant species showing major changes in response to incubation temperatures and less dormant species in response to cold stratification periods. Plants developed under warmer climates will produce seeds with changed germination responses to temperature and/or cold stratification, but the extent of these changes across species could be driven by seed dormancy traits. Transgenerational plastic adjustments of seed germination and dormancy shown here may result from increased seed viability, reduced primary and secondary dormancy state, or both, and may play a crucial role in future plant adaptation to climate change. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The effect of simulated cold weather transport on core body temperature and behavior of broilers.

PubMed

Strawford, M L; Watts, J M; Crowe, T G; Classen, H L; Shand, P J

2011-11-01

During the winter in Western Canada, broilers are routinely transported in ambient temperatures ranging from 0°C to -40°C, yet there is little research in this area. This study examined the physiology and behavior of broilers undergoing simulated transport at typical Western Canadian winter temperatures. Groups of 15 broilers aged 32 to 33 d were exposed to an air stream regulated to -5, -10, or -15°C. Birds were placed into a typical transport drawer. Following baseline observations, the drawer was placed into a test chamber where cold air was drawn past the birds for 3 h. Three replications were conducted at each temperature. The birds adjusted their position within the drawer based upon the temperature distribution within the drawer. In comparison to the baseline period, exposing the birds to a cold air stream caused them to avoid the front plane (P = 0.003) which was the coldest area within the drawer. The birds did not adjust their usage of the middle (P = 0.308) and rear (P = 0.640) planes, because these were the warmer areas within the drawer. The total amount of space the birds occupied within the drawer did not decrease when exposed to the test chamber (P = 0.669). The core body temperature (CBT) did not vary and was within the known normal range during the normal (P = 0.528), pre-chamber (P = 0.060), and post-chamber (P = 0.285) periods. The CBT of the birds significantly decreased during the in-chamber period (P < 0.001) and then increased during the lairage period (P < 0.001). The shrink loss (P = 0.981) and amount of time to resume feed consumption (P = 0.357) were not affected by exposing the birds to temperatures of -5°C and colder. Exposing birds to temperatures of -5°C and colder had a negative effect on the CBT of the birds. However, the birds demonstrated behaviors which mitigated the negative effect that cold exposure could have on their CBT.

Climate and foraging mode explain interspecific variation in snake metabolic rates.

PubMed

Dupoué, Andréaz; Brischoux, François; Lourdais, Olivier

2017-11-29

The energy cost of self-maintenance is a critical facet of life-history strategies. Clarifying the determinant of interspecific variation in metabolic rate (MR) at rest is important to understand and predict ecological patterns such as species distributions or responses to climatic changes. We examined variation of MR in snakes, a group characterized by a remarkable diversity of activity rates and a wide distribution. We collated previously published MR data ( n = 491 observations) measured in 90 snake species at different trial temperatures. We tested for the effects of metabolic state (standard MR (SMR) versus resting MR (RMR)), foraging mode (active versus ambush foragers) and climate (temperature and precipitation) while accounting for non-independence owing to phylogeny, body mass and thermal dependence. We found that RMR was 40% higher than SMR, and that active foragers have higher MR than species that ambush their prey. We found that MR was higher in cold environments, supporting the metabolic cold adaptation hypothesis. We also found an additive and positive effect of precipitation on MR suggesting that lower MR in arid environments may decrease dehydration and energetic costs. Altogether, our findings underline the complex influences of climate and foraging mode on MR and emphasize the relevance of these facets to understand the physiological impact of climate change. © 2017 The Author(s).

RAN1 is involved in plant cold resistance and development in rice (Oryza sativa).

PubMed

Xu, Peipei; Cai, Weiming

2014-07-01

Of the diverse abiotic stresses, low temperature is one of the major limiting factors that lead to a series of morphological, physiological, biochemical, and molecular changes in plants. Ran, an evolutionarily conserved small G-protein family, has been shown to be essential for the nuclear translocation of proteins. It also mediates the regulation of cell cycle progression in mammalian cells. However, little is known about Ran function in rice (Oryza sativa). We report here that Ran gene OsRAN1 is essential for the molecular improvement of rice for cold tolerance. Ran also affects plant morphogenesis in transgenic Arabidopsis thaliana. OsRAN1 is ubiquitously expressed in rice tissues with the highest expression in the spike. The levels of mRNA encoding OsRAN1 were greatly increased by cold and indoleacetic acid treatment rather than by addition of salt and polyethylene glycol. Further, OsRAN1 overexpression in Arabidopsis increased tiller number, and altered root development. OsRAN1 overexpression in rice improves cold tolerance. The levels of cellular free Pro and sugar levels were highly increased in transgenic plants under cold stress. Under cold stress, OsRAN1 maintained cell division and cell cycle progression, and also promoted the formation of an intact nuclear envelope. The results suggest that OsRAN1 protein plays an important role in the regulation of cellular mitosis and the auxin signalling pathway. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Comparison of different cooling regimes within a shortened liquid cooling/warming garment on physiological and psychological comfort during exercise

NASA Technical Reports Server (NTRS)

Leon, Gloria R.; Koscheyev, Victor S.; Coca, Aitor; List, Nathan

2004-01-01

The aim of this study was to compare the effectiveness of different cooling regime intensities to maintain physiological and subjective comfort during physical exertion levels comparable to that engaged in during extravehicular activities (EVA) in space. We studied eight subjects (six males, two females) donned in our newly developed physiologically based shortened liquid cooling/warming garment (SLCWG). Rigorous (condition 1) and mild (condition 2) water temperature cooling regimes were compared at physical exertion levels comparable to that performed during EVA to ascertain the effectiveness of a lesser intensity of cooling in maintaining thermal comfort, thus reducing energy consumption in the portable life support system. Exercise intensity was varied across stages of the session. Finger temperature, rectal temperature, and subjective perception of overall body and hand comfort were assessed. Finger temperature was significantly higher in the rigorous cooling condition and showed a consistent increase across exercise stages, likely due to the restriction of heat extraction because of the intensive cold. In the mild cooling condition, finger temperature exhibited an overall decline with cooling, indicating greater heat extraction from the body. Rectal temperature was not significantly different between conditions, and showed a steady increase over exercise stages in both rigorous and mild cooling conditions. Ratings of overall comfort were 30% higher (more positive) and more stable in mild cooling (p<0.001). The mild cooling regime was more effective than rigorous cooling in allowing the process of heat exchange to occur, thus maintaining thermal homeostasis and subjective comfort during physical exertion.

Physiological responses and lipid storage of the coral Lophelia pertusa at varying food density.

PubMed

Baussant, Thierry; Nilsen, Marianne; Ravagnan, Elisa; Westerlund, Stig; Ramanand, Sreerekha

2017-01-01

Despite the importance of the cold-water coral Lophelia pertusa to deep-sea reef ecosystem functioning, current knowledge of key physiological responses to available food resources is scarce. Scenarios with varying food density may help to understand how corals deal with seasonal variations in the dark ocean and might be used to study consequences of anthropogenic activities potentially affecting food availability. Thus, the physiological responses of L. pertusa to varying food (Artemia salina nauplii) concentration, ranging from 20% to 300% of carbon equivalent turned over by basal coral respiration, were investigated. A starvation group was also included. Measurements of respiration, growth, mucus production, and energy reserves (storage fatty acids) were performed at several time intervals over 26 weeks. In general, data showed a stronger effect of experimental time on measured responses, but no significant influence of food density treatment. In starved corals, respiration rate declined to 52% of initial respiration, while skeleton growth rate was maintained at the same rate as Artemia-fed corals throughout the investigation. Mucus production measured as the sum of dissolved organic carbon (DOC) and particulate organic carbon (POC) was also similar across food treatments, but POC production exceeded that of DOC at the highest food density. No marked effect was observed on storage fatty acids. These results confirm that L. pertusa is highly resilient to environmental conditions with suboptimal food densities over a time scale of months. Regulation of several physiological processes, including respiration and mucus production, possibly in combination with an opportunistic feeding strategy, contributed to this tolerance to maintain viable corals. Thus, it appears that L. pertusa is well adapted to life in the deep sea.

Proteomic analysis of Oenococcus oeni freeze-dried culture to assess the importance of cell acclimation to conduct malolactic fermentation in wine.

PubMed

Cecconi, Daniela; Milli, Alberto; Rinalducci, Sara; Zolla, Lello; Zapparoli, Giacomo

2009-09-01

Cultures of Oenococcus oeni, the most important malolactic bacterium, are used to induce malolactic fermentation in wine. Survival assays in two different wines confirmed that cells acclimated for 24 h in half-strength wine-like medium (acclimation medium) enhanced the malolactic performances. To investigate the effect of the pre-incubation phase on cell physiology, a proteomic study was carried out. Total protein extracts of acclimated and non-acclimated cell cultures (control) were analyzed by 2-D-PAGE. A total of 20 out of approximately 400 spots varied significantly. All the spots were identified by MS analysis and most of them were proteins involved in metabolism, transcription/translation processes and stress response. The results revealed the different physiological status between non-acclimated and acclimated cells explaining, in part, their different behavior in wine. Regulation of stress proteins such as heat and cold shock proteins was involved. Moreover, the availability of sugars and amino acids (even if at low concentration) in acclimation medium determined a modulation of energy metabolism enhancing the resistance to stressful conditions (as those that cells find in wine when inoculated). Finally, this proteomic study increased knowledge concerning the physiological changes in freeze-dried culture occurring with pre-inoculation procedures.

Surviving in a frozen desert: environmental stress physiology of terrestrial Antarctic arthropods.

PubMed

Teets, Nicholas M; Denlinger, David L

2014-01-01

Abiotic stress is one of the primary constraints limiting the range and success of arthropods, and nowhere is this more apparent than Antarctica. Antarctic arthropods have evolved a suite of adaptations to cope with extremes in temperature and water availability. Here, we review the current state of knowledge regarding the environmental physiology of terrestrial arthropods in Antarctica. To survive low temperatures, mites and Collembola are freeze-intolerant and rely on deep supercooling, in some cases supercooling below -30°C. Also, some of these microarthropods are capable of cryoprotective dehydration to extend their supercooling capacity and reduce the risk of freezing. In contrast, the two best-studied Antarctic insects, the midges Belgica antarctica and Eretmoptera murphyi, are freeze-tolerant year-round and rely on both seasonal and rapid cold-hardening to cope with decreases in temperature. A common theme among Antarctic arthropods is extreme tolerance of dehydration; some accomplish this by cuticular mechanisms to minimize water loss across their cuticle, while a majority have highly permeable cuticles but tolerate upwards of 50-70% loss of body water. Molecular studies of Antarctic arthropod stress physiology are still in their infancy, but several recent studies are beginning to shed light on the underlying mechanisms that govern extreme stress tolerance. Some common themes that are emerging include the importance of cuticular and cytoskeletal rearrangements, heat shock proteins, metabolic restructuring and cell recycling pathways as key mediators of cold and water stress in the Antarctic.

Laser refrigeration of hydrothermal nanocrystals in physiological media.

PubMed

Roder, Paden B; Smith, Bennett E; Zhou, Xuezhe; Crane, Matthew J; Pauzauskie, Peter J

2015-12-08

Coherent laser radiation has enabled many scientific and technological breakthroughs including Bose-Einstein condensates, ultrafast spectroscopy, superresolution optical microscopy, photothermal therapy, and long-distance telecommunications. However, it has remained a challenge to refrigerate liquid media (including physiological buffers) during laser illumination due to significant background solvent absorption and the rapid (∼ ps) nonradiative vibrational relaxation of molecular electronic excited states. Here we demonstrate that single-beam laser trapping can be used to induce and quantify the local refrigeration of physiological media by >10 °C following the emission of photoluminescence from upconverting yttrium lithium fluoride (YLF) nanocrystals. A simple, low-cost hydrothermal approach is used to synthesize polycrystalline particles with sizes ranging from <200 nm to >1 μm. A tunable, near-infrared continuous-wave laser is used to optically trap individual YLF crystals with an irradiance on the order of 1 MW/cm(2). Heat is transported out of the crystal lattice (across the solid-liquid interface) by anti-Stokes (blue-shifted) photons following upconversion of Yb(3+) electronic excited states mediated by the absorption of optical phonons. Temperatures are quantified through analysis of the cold Brownian dynamics of individual nanocrystals in an inhomogeneous temperature field via forward light scattering in the back focal plane. The cold Brownian motion (CBM) analysis of individual YLF crystals indicates local cooling by >21 °C below ambient conditions in D2O, suggesting a range of potential future applications including single-molecule biophysics and integrated photonic, electronic, and microfluidic devices.

Laser refrigeration of hydrothermal nanocrystals in physiological media

PubMed Central

Roder, Paden B.; Smith, Bennett E.; Zhou, Xuezhe; Crane, Matthew J.; Pauzauskie, Peter J.

2015-01-01

Coherent laser radiation has enabled many scientific and technological breakthroughs including Bose–Einstein condensates, ultrafast spectroscopy, superresolution optical microscopy, photothermal therapy, and long-distance telecommunications. However, it has remained a challenge to refrigerate liquid media (including physiological buffers) during laser illumination due to significant background solvent absorption and the rapid (∼ps) nonradiative vibrational relaxation of molecular electronic excited states. Here we demonstrate that single-beam laser trapping can be used to induce and quantify the local refrigeration of physiological media by >10 °C following the emission of photoluminescence from upconverting yttrium lithium fluoride (YLF) nanocrystals. A simple, low-cost hydrothermal approach is used to synthesize polycrystalline particles with sizes ranging from <200 nm to >1 μm. A tunable, near-infrared continuous-wave laser is used to optically trap individual YLF crystals with an irradiance on the order of 1 MW/cm2. Heat is transported out of the crystal lattice (across the solid–liquid interface) by anti-Stokes (blue-shifted) photons following upconversion of Yb3+ electronic excited states mediated by the absorption of optical phonons. Temperatures are quantified through analysis of the cold Brownian dynamics of individual nanocrystals in an inhomogeneous temperature field via forward light scattering in the back focal plane. The cold Brownian motion (CBM) analysis of individual YLF crystals indicates local cooling by >21 °C below ambient conditions in D2O, suggesting a range of potential future applications including single-molecule biophysics and integrated photonic, electronic, and microfluidic devices. PMID:26589813

Sex-dependent effects of cannabis-induced analgesia.

PubMed

Cooper, Ziva D; Haney, Margaret

2016-10-01

Preclinical studies demonstrate that cannabinoid-mediated antinociceptive effects vary according to sex; it is unknown if these findings extend to humans. This retrospective analysis compared the analgesic, subjective and physiological effects of active cannabis (3.56-5.60% THC) and inactive cannabis (0.00% THC) in male (N=21) and female (N=21) cannabis smokers under double-blind, placebo-controlled conditions. Pain response was measured using the Cold-Pressor Test (CPT). Participants immersed their hand in cold water (4°C); times to report pain (pain sensitivity) and withdraw the hand (pain tolerance) were recorded. Subjective drug ratings were also measured. Among men, active cannabis significantly decreased pain sensitivity relative to inactive cannabis (p<0.01). In women, active cannabis failed to decrease pain sensitivity relative to inactive. Active cannabis increased pain tolerance in both men women immediately after smoking (p<0.001); a trend was observed for differences between men and women (p<0.10). Active cannabis also increased subjective ratings of cannabis associated with abuse liability ('Take again,' 'Liking,' 'Good drug effect'), drug strength, and 'High' relative to inactive in both men and women (p<0.01). These results indicate that in cannabis smokers, men exhibit greater cannabis-induced analgesia relative to women. These sex-dependent differences are independent of cannabis-elicited subjective effects associated with abuse-liability, which were consistent between men and women. As such, sex-dependent differences in cannabis's analgesic effects are an important consideration that warrants further investigation when considering the potential therapeutic effects of cannabinoids for pain relief. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Cold stress improves the ability of Lactobacillus plantarum L67 to survive freezing.

PubMed

Song, Sooyeon; Bae, Dong-Won; Lim, Kwangsei; Griffiths, Mansel W; Oh, Sejong

2014-11-17

The stress resistance of bacteria is affected by the physiological status of the bacterial cell and environmental factors such as pH, salts and temperature. In this study, we report on the stress response of Lactobacillus plantarum L67 after four consecutive freeze-thaw cycles. The cold stress response of the cold-shock protein genes (cspC, cspL and cspP) and ATPase activities were then evaluated. The cold stress was adjusted to 5 °C when the bacteria were growing at the mid-exponential phase. A comparative proteomic analysis was performed with two-dimensional gel electrophoresis (2D SDS-PAGE) and a matrix assisted laser desorption/ionization-mass spectrometer. Only 56% of the L. plantarum L67 cells without prior exposure to cold stress survived after four consecutive freeze-thaw cycles. However, 78% of the L. plantarum L67 cells that were treated with cold stress at 5 °C for 6 h survived after freeze-thaw conditions. After applying cold stress to the culture for 6h, the cells were then stored for 60 days at 5 °C, 25 °C and 35 °C separately. The cold-stressed culture of L. plantarum L67 showed an 8% higher viability than the control culture. After applying cold stress for 6h, the transcript levels of two genes (cspP and cspL) were up-regulated 1.4 (cspP) and 1.2 (cspL) times compared to the control. However, cspC was not up-regulated. A proteomic analysis showed that the proteins increased after a reduction of the incubation temperature to 5 °C. The importance of the expression of 13 other relevant proteins was also determined through the study. The exposure of L. plantarum cells to low temperatures aids their ability to survive through subsequent freeze-thaw processes and lyophilization. Copyright © 2014. Published by Elsevier B.V.

Effects of cold temperatures on the excitability of rat trigeminal ganglion neurons that are not for cold-sensing

PubMed Central

Kanda, Hirosato; Gu, Jianguo G.

2016-01-01

Except a small population of primary afferent neurons for sensing cold to generate the sensations of innocuous and noxious cold, it is generally believed that cold temperatures suppress the excitability of other primary afferent neurons that are not for cold-sensing. These not-for-cold-sensing neurons include the majority of non-nociceptive and nociceptive afferent neurons. In the present study we have found that not-for-cold-sensing neurons of rat trigeminal ganglia (TG) change their excitability in several ways at cooling temperatures. In nearly 70% of not-for-cold-sensing TG neurons, the cooling temperature of 15°C increases their membrane excitability. We regard these neurons as cold-active neurons. For the remaining 30% of not-for-cold-sensing TG neurons, the cooling temperature of 15°C either has no effect (regarded as cold-ineffective neurons) or suppress (regarded as cold-suppressive neurons) their membrane excitability. For cold-active neurons, the cold temperature of 15°C increases their excitability as is evidenced by the increases in action potential (AP) firing numbers and/or reduction of AP rheobase when these neurons are depolarized electrically. The cold temperature of 15°C significantly inhibits M-currents and increases membrane input resistance of cold-active neurons. Retigabine, an M-current activator, abolishes the effect of cold temperatures on AP firing but not the effect of cold temperature on AP rheobase levels. The inhibition of M-currents and the increases of membrane input resistance are likely two mechanisms by which cooling temperatures increase the excitability of not-for-cold-sensing TG neurons. PMID:26709732

Effects of cold temperatures on the excitability of rat trigeminal ganglion neurons that are not for cold sensing.

PubMed

Kanda, Hirosato; Gu, Jianguo G

2017-05-01

Aside from a small population of primary afferent neurons for sensing cold, which generate sensations of innocuous and noxious cold, it is generally believed that cold temperatures suppress the excitability of primary afferent neurons not responsible for cold sensing. These not-for-cold-sensing neurons include the majority of non-nociceptive and nociceptive afferent neurons. In this study we have found that the not-for-cold-sensing neurons of rat trigeminal ganglia (TG) change their excitability in several ways at cooling temperatures. In nearly 70% of not-for-cold-sensing TG neurons, a cooling temperature of 15°C increases their membrane excitability. We regard these neurons as cold-active neurons. For the remaining 30% of not-for-cold-sensing TG neurons, the cooling temperature of 15°C either has no effect (cold-ineffective neurons) or suppress their membrane excitability (cold-suppressive neurons). For cold-active neurons, the cold temperature of 15°C increases their excitability as is evidenced by increases in action potential (AP) firing numbers and/or the reduction in AP rheobase when these neurons are depolarized electrically. The cold temperature of 15°C significantly inhibits M-currents and increases membrane input resistance of cold-active neurons. Retigabine, an M-current activator, abolishes the effect of cold temperatures on AP firing, but not the effect of cold temperature on AP rheobase levels. The inhibition of M-currents and the increases of membrane input resistance are likely two mechanisms by which cooling temperatures increase the excitability of not-for-cold-sensing TG neurons. This article is part of the special article series "Pain". © 2015 International Society for Neurochemistry.

Stress and physiological, behavioral and performance patterns of children under varied air ion levels

NASA Astrophysics Data System (ADS)

Fornof, K. T.; Gilbert, G. O.

1988-12-01

The possibility that individual differences in reactivity to stressors are a major factor underlying discordant results reported for air ion studies prompted an investigation of response patterns in school children under both normal indoor air ion levels and moderately increased negative air ion levels (4000±500/cm3). It was hypothesized that the impact of stressors is reduced with high negative air ionization, and that resultant changes in stress effects would be differentially exhibited according to the children's normal degree of stimulus reactivity. A counter-balanced, replicative, withinssubject design was selected, and the subjects were 12 environmentally sensitive, 1st 4th grade school children. In addition to monitoring stress effects on activity level, attention span, concentration to task and conceptual performance, measures were also made of urinary 5-hydroxyindole acetic acid levels and skin resistance response (SRR) to determine if changes extended to the physiological state. The cold water test was used to add physical stress and enable calculations of Lacey's autonomic lability scores (ALS) as indicators of individual reactivity. The results show main effects for air ions on both physiological parameters, with 48% less change in %SRR ( P<0.01) and 46% less change in urinary 5-HIAA levels ( P<0.055) during negative air ions, indicating increased stress tolerance. Strong interactive effects for ALS x air ion condition appeared, with high and low ALS children reacting oppositely to negative air ions in measures of skin resistance level ( P<0.01), wrist activity ( P<0.01) and digit span backwards ( P<0.004). Thus individual differences in autonomic reactivity and the presence or absence of stressors appear as critical elements for internal validity, and in preventing consequent skewed results from obscuring progress in air ion research.

Evaluating the role of fronts in habitat overlaps between cold and warm water species in the western North Pacific: A proof of concept

NASA Astrophysics Data System (ADS)

Mugo, Robinson M.; Saitoh, Sei-Ichi; Takahashi, Fumihiro; Nihira, Akira; Kuroyama, Tadaaki

2014-09-01

Cold- and warm-water species' fishing grounds show a spatial synchrony around fronts in the western North Pacific (WNP). However, it is not yet clear whether a front (thermal, salinity or chlorophyll) acts as an absolute barrier to fish migration on either side or its structure allows interaction of species with different physiological requirements. Our objective was to assess potential areas of overlap between cold- and warm-water species using probabilities of presence derived from fishery datasets and remotely sensed environment data in the Kuroshio-Oyashio region in the WNP. Fishery data comprised skipjack tuna (Katsuwonus pelamis) fishing locations and proxy presences (derived from fishing night light images) for neon flying squid (Ommastrephes bartrami) and Pacific saury (Cololabis saira). Monthly (August-November) satellite remotely sensed sea-surface temperature, chlorophyll-a and sea-surface height anomaly images were used as environment data. Maximum entropy (MaxEnt) models were used to determine probabilities of presence (PoP) for each set of fishery and environment data for the area 35-45°N and 140-160°E. Maps of both sets of PoPs were compared and areas of overlap identified using a combined probability map. Results indicated that areas of spatial overlap existed among the species habitats, which gradually widened from September to November. The reasons for these overlaps include the presence of strong thermal/ocean-color gradients between cold Oyashio and warm Kuroshio waters, and also the presence of the sub-arctic front. Due to the high abundance of food along frontal zones, the species use the fronts as foraging grounds while confining within physiologically tolerable waters on either side of the front. The interaction zone around the front points to areas that might be accessible to both species for foraging, which suggests intense prey-predator interaction zones.

Fluid mechanics in dentinal microtubules provides mechanistic insights into the difference between hot and cold dental pain.

PubMed

Lin, Min; Luo, Zheng Yuan; Bai, Bo Feng; Xu, Feng; Lu, Tian Jian

2011-03-23

Dental thermal pain is a significant health problem in daily life and dentistry. There is a long-standing question regarding the phenomenon that cold stimulation evokes sharper and more shooting pain sensations than hot stimulation. This phenomenon, however, outlives the well-known hydrodynamic theory used to explain dental thermal pain mechanism. Here, we present a mathematical model based on the hypothesis that hot or cold stimulation-induced different directions of dentinal fluid flow and the corresponding odontoblast movements in dentinal microtubules contribute to different dental pain responses. We coupled a computational fluid dynamics model, describing the fluid mechanics in dentinal microtubules, with a modified Hodgkin-Huxley model, describing the discharge behavior of intradental neuron. The simulated results agreed well with existing experimental measurements. We thence demonstrated theoretically that intradental mechano-sensitive nociceptors are not "equally sensitive" to inward (into the pulp) and outward (away from the pulp) fluid flows, providing mechanistic insights into the difference between hot and cold dental pain. The model developed here could enable better diagnosis in endodontics which requires an understanding of pulpal histology, neurology and physiology, as well as their dynamic response to the thermal stimulation used in dental practices.

Fluid Mechanics in Dentinal Microtubules Provides Mechanistic Insights into the Difference between Hot and Cold Dental Pain

PubMed Central

Lin, Min; Luo, Zheng Yuan; Bai, Bo Feng; Xu, Feng; Lu, Tian Jian

2011-01-01

Dental thermal pain is a significant health problem in daily life and dentistry. There is a long-standing question regarding the phenomenon that cold stimulation evokes sharper and more shooting pain sensations than hot stimulation. This phenomenon, however, outlives the well-known hydrodynamic theory used to explain dental thermal pain mechanism. Here, we present a mathematical model based on the hypothesis that hot or cold stimulation-induced different directions of dentinal fluid flow and the corresponding odontoblast movements in dentinal microtubules contribute to different dental pain responses. We coupled a computational fluid dynamics model, describing the fluid mechanics in dentinal microtubules, with a modified Hodgkin-Huxley model, describing the discharge behavior of intradental neuron. The simulated results agreed well with existing experimental measurements. We thence demonstrated theoretically that intradental mechano-sensitive nociceptors are not “equally sensitive” to inward (into the pulp) and outward (away from the pulp) fluid flows, providing mechanistic insights into the difference between hot and cold dental pain. The model developed here could enable better diagnosis in endodontics which requires an understanding of pulpal histology, neurology and physiology, as well as their dynamic response to the thermal stimulation used in dental practices. PMID:21448459

Delayed response to cold stress is characterized by successive metabolic shifts culminating in apple fruit peel necrosis.

PubMed

Gapper, Nigel E; Hertog, Maarten L A T M; Lee, Jinwook; Buchanan, David A; Leisso, Rachel S; Fei, Zhangjun; Qu, Guiqin; Giovannoni, James J; Johnston, Jason W; Schaffer, Robert J; Nicolaï, Bart M; Mattheis, James P; Watkins, Christopher B; Rudell, David R

2017-04-21

Superficial scald is a physiological disorder of apple fruit characterized by sunken, necrotic lesions appearing after prolonged cold storage, although initial injury occurs much earlier in the storage period. To determine the degree to which the transition to cell death is an active process and specific metabolism involved, untargeted metabolic and transcriptomic profiling was used to follow metabolism of peel tissue over 180 d of cold storage. The metabolome and transcriptome of peel destined to develop scald began to diverge from peel where scald was controlled using antioxidant (diphenylamine; DPA) or rendered insensitive to ethylene using 1-methylcyclopropene (1-MCP) beginning between 30 and 60 days of storage. Overall metabolic and transcriptomic shifts, representing multiple pathways and processes, occurred alongside α-farnesene oxidation and, later, methanol production alongside symptom development. Results indicate this form of peel necrosis is a product of an active metabolic transition involving multiple pathways triggered by chilling temperatures at cold storage inception rather than physical injury. Among multiple other pathways, enhanced methanol and methyl ester levels alongside upregulated pectin methylesterases are unique to peel that is developing scald symptoms similar to injury resulting from mechanical stress and herbivory in other plants.

Transcription Factor CBF4 Is a Regulator of Drought Adaptation in Arabidopsis1

PubMed Central

Haake, Volker; Cook, Daniel; Riechmann, José Luis; Pineda, Omaira; Thomashow, Michael F.; Zhang, James Z.

2002-01-01

In plants, low temperature and dehydration activate a set of genes containing C-repeat/dehydration-responsive elements in their promoter. It has been shown previously that the Arabidopsis CBF/DREB1 transcription activators are critical regulators of gene expression in the signal transduction of cold acclimation. Here, we report the isolation of an apparent homolog of the CBF/DREB1 proteins (CBF4) that plays the equivalent role during drought adaptation. In contrast to the three already identified CBF/DREB1 homologs, which are induced under cold stress, CBF4 gene expression is up-regulated by drought stress, but not by low temperature. Overexpression of CBF4 in transgenic Arabidopsis plants results in the activation of C-repeat/dehydration-responsive element containing downstream genes that are involved in cold acclimation and drought adaptation. As a result, the transgenic plants are more tolerant to freezing and drought stress. Because of the physiological similarity between freezing and drought stress, and the sequence and structural similarity of the CBF/DREB1 and the CBF4 proteins, we propose that the plant's response to cold and drought evolved from a common CBF-like transcription factor, first through gene duplication and then through promoter evolution. PMID:12376631

Early Cold-Induced Peroxidases and Aquaporins Are Associated With High Cold Tolerance in Dajiao (Musa spp. ‘Dajiao’)

PubMed Central

He, Wei-Di; Gao, Jie; Dou, Tong-Xin; Shao, Xiu-Hong; Bi, Fang-Cheng; Sheng, Ou; Deng, Gui-Ming; Li, Chun-Yu; Hu, Chun-Hua; Liu, Ji-Hong; Zhang, Sheng; Yang, Qiao-Song; Yi, Gan-Jun

2018-01-01

Banana is an important tropical fruit with high economic value. One of the main cultivars (‘Cavendish’) is susceptible to low temperatures, while another closely related specie (‘Dajiao’) has considerably higher cold tolerance. We previously reported that some membrane proteins appear to be involved in the cold tolerance of Dajiao bananas via an antioxidation mechanism. To investigate the early cold stress response of Dajiao, here we applied comparative membrane proteomics analysis for both cold-sensitive Cavendish and cold-tolerant Dajiao bananas subjected to cold stress at 10°C for 0, 3, and 6 h. A total of 2,333 and 1,834 proteins were identified in Cavendish and Dajiao, respectively. Subsequent bioinformatics analyses showed that 692 Cavendish proteins and 524 Dajiao proteins were predicted to be membrane proteins, of which 82 and 137 differentially abundant membrane proteins (DAMPs) were found in Cavendish and Dajiao, respectively. Interestingly, the number of DAMPs with increased abundance following 3 h of cold treatment in Dajiao (80) was seven times more than that in Cavendish (11). Gene ontology molecular function analysis of DAMPs for Cavendish and Dajiao indicated that they belong to eight categories including hydrolase activity, binding, transporter activity, antioxidant activity, etc., but the number in Dajiao is twice that in Cavendish. Strikingly, we found peroxidases (PODs) and aquaporins among the protein groups whose abundance was significantly increased after 3 h of cold treatment in Dajiao. Some of the PODs and aquaporins were verified by reverse-transcription PCR, multiple reaction monitoring, and green fluorescent protein-based subcellular localization analysis, demonstrating that the global membrane proteomics data are reliable. By combining the physiological and biochemical data, we found that membrane-bound Peroxidase 52 and Peroxidase P7, and aquaporins (MaPIP1;1, MaPIP1;2, MaPIP2;4, MaPIP2;6, MaTIP1;3) are mainly involved in decreased lipid peroxidation and maintaining leaf cell water potential, which appear to be the key cellular adaptations contributing to the cold tolerance of Dajiao. This membrane proteomics study provides new insights into cold stress tolerance mechanisms of banana, toward potential applications for ultimate genetic improvement of cold tolerance in banana. PMID:29568304

Effects of temperature acclimation on Pacific bluefin tuna (Thunnus orientalis) cardiac transcriptome.

PubMed

Jayasundara, Nishad; Gardner, Luke D; Block, Barbara A

2013-11-01

Little is known about the mechanisms underpinning thermal plasticity of vertebrate hearts. Bluefin tuna hearts offer a unique model to investigate processes underlying thermal acclimation. Their hearts, while supporting an endothermic physiology, operate at ambient temperature, and are presented with a thermal challenge when migrating to different thermal regimes. Here, we examined the molecular responses in atrial and ventricular tissues of Pacific bluefin tuna acclimated to 14°C, 20°C, and 25°C. Quantitative PCR studies showed an increase in sarcoplasmic reticulum Ca(2+) ATPase gene expression with cold acclimation and an induction of Na(+)/Ca(2+)-exchanger gene at both cold and warm temperatures. These data provide evidence for thermal plasticity of excitation-contraction coupling gene expression in bluefin tunas and indicate an increased capacity for internal Ca(2+) storage in cardiac myocytes at 14°C. Transcriptomic analysis showed profound changes in cardiac tissues with acclimation. A principal component analysis revealed that temperature effect was greatest on gene expression in warm-acclimated atrium. Overall data showed an increase in cardiac energy metabolism at 14°C, potentially compensating for cold temperature to optimize bluefin tuna performance in colder oceans. In contrast, metabolic enzyme activity and gene expression data suggest a decrease in ATP production at 25°C. Expression of genes involved in protein turnover and molecular chaperones was also decreased at 25°C. Expression of genes involved in oxidative stress response and programmed cell death suggest an increase in oxidative damage and apoptosis at 25°C, particularly in the atrium. These findings provide insights into molecular processes that may characterize cardiac phenotypes at upper thermal limits of teleosts.

Neuronal hyperexcitability in the ventral posterior thalamus of neuropathic rats: modality selective effects of pregabalin.

PubMed

Patel, Ryan; Dickenson, Anthony H

2016-07-01

Neuropathic pain represents a substantial clinical challenge; understanding the underlying neural mechanisms and back-translation of therapeutics could aid targeting of treatments more effectively. The ventral posterior thalamus (VP) is the major termination site for the spinothalamic tract and relays nociceptive activity to the somatosensory cortex; however, under neuropathic conditions, it is unclear how hyperexcitability of spinal neurons converges onto thalamic relays. This study aimed to identify neural substrates of hypersensitivity and the influence of pregabalin on central processing. In vivo electrophysiology was performed to record from VP wide dynamic range (WDR) and nociceptive-specific (NS) neurons in anesthetized spinal nerve-ligated (SNL), sham-operated, and naive rats. In neuropathic rats, WDR neurons had elevated evoked responses to low- and high-intensity punctate mechanical stimuli, dynamic brushing, and innocuous and noxious cooling, but less so to heat stimulation, of the receptive field. NS neurons in SNL rats also displayed increased responses to noxious punctate mechanical stimulation, dynamic brushing, noxious cooling, and noxious heat. Additionally, WDR, but not NS, neurons in SNL rats exhibited substantially higher rates of spontaneous firing, which may correlate with ongoing pain. The ratio of WDR-to-NS neurons was comparable between SNL and naive/sham groups, suggesting relatively few NS neurons gain sensitivity to low-intensity stimuli leading to a "WDR phenotype." After neuropathy was induced, the proportion of cold-sensitive WDR and NS neurons increased, supporting the suggestion that changes in frequency-dependent firing and population coding underlie cold hypersensitivity. In SNL rats, pregabalin inhibited mechanical and heat responses but not cold-evoked or elevated spontaneous activity. Copyright © 2016 the American Physiological Society.

Changes of jugular venous blood temperature associated with measurements of cerebral blood flow using the transcerebral double-indicator dilution technique.

PubMed

Mielck, F; Bräuer, A; Radke, O; Hanekop, G; Loesch, S; Friedrich, M; Hilgers, R; Sonntag, H

2004-04-01

The transcerebral double-indicator dilution technique is a recently developed method to measure global cerebral blood flow at bedside. It is based on bolus injection of ice-cold indocyanine green dye and simultaneous recording of resulting thermo- and dye-dilution curves in the aorta and the jugular bulb. However, with this method 40 mL of ice-cold solution is administered as a bolus. Therefore, this prospective clinical study was performed to elucidate the effects of repeated administration of indicator on absolute blood temperature and on cerebral blood flow and metabolism. The investigation was performed in nine male patients scheduled for elective coronary artery bypass grafting. Absolute blood temperature was measured in the jugular bulb and in the aorta before and after repeated measurements using the transcerebral double-indicator dilution technique. During the investigated time course, the blood temperature in the jugular bulb, compared to the aorta, was significantly higher with a mean difference of 0.21 degrees C. The administration of an ice-cold bolus reduced the mean blood temperature by 0.06 degrees C in the jugular bulb as well as in the aorta. After the transcerebral double-indicator dilution measurements a temperature recovery to baseline conditions was not observed during the investigated time period. Cerebral blood flow and cerebral metabolism did not change during the investigated time period. Repeated measurements with the transcerebral double-indicator dilution technique do not affect absolute jugular bulb blood temperatures negatively. Global cerebral blood flow and metabolism measurements remain unaltered. However, accuracy and resolution of this technique is not high enough to detect the effect of minor changes of physiological variables.

Basic cryogenics and materials. Phase 1

NASA Technical Reports Server (NTRS)

Wigley, D. A.

1985-01-01

The effects of cryogenic temperatures on the mechanical and physical properties of materials are summarized. Heat capacity and thermal conductivity are considered in the context of conservation of liquid nitrogen, thermal stability of the gas stream, and the response time for changes in operating temperature. Particular attention is given to the effects of differential expansion and failure due to thermal fatigue. Factors affecting safety are discussed, including hazards created due to the inadvertent production of liquid oxygen and the physiological effects of exposure to liquid and gaseous nitrogen, such as cold burns and asphyxiation. The preference for using f.c.c. metals at low temperatures is explained in terms of their superior toughness. The limitations on the use of ferritic steels is also considered. Nonmetallic materials are discussed, mainly in the context of their LOX compatibility and their use in the form of foams and fibers as insultants, seals, and fiber reinforced composites.

Basic cryogenics and materials

NASA Technical Reports Server (NTRS)

Wigley, D. A.

1985-01-01

The effects of cryogenic temperatures on the mechanical and physical properties of materials are summarized. Heat capacity and thermal conductivity are considered in the context of conservation of liquid nitrogen, thermal stability of the gas stream, and the response time for changes in operating temperature. Particular attention is given to the effects of differential expansion and failure due to thermal fatigue. Factors affecting safety are discussed, including hazards created due to the inadvertent production of liquid oxygen and the physiological effects of exposure to liquid and gaseous nitrogen, such as cold burns and asphyxiation. The preference for using f.c.c. metals at low temperatures is explained in terms of their superior toughness. The limitations on the use of ferritic steels is also considered. Nonmetallic materials are discussed, mainly in the context of their LOX compatibility and their use in the form of foams and fibers as insulatants, seals, and fiber reinforced composites.

Basic cryogenics and materials

NASA Astrophysics Data System (ADS)

Wigley, D. A.

1985-07-01

The effects of cryogenic temperatures on the mechanical and physical properties of materials are summarized. Heat capacity and thermal conductivity are considered in the context of conservation of liquid nitrogen, thermal stability of the gas stream, and the response time for changes in operating temperature. Particular attention is given to the effects of differential expansion and failure due to thermal fatigue. Factors affecting safety are discussed, including hazards created due to the inadvertent production of liquid oxygen and the physiological effects of exposure to liquid and gaseous nitrogen, such as cold burns and asphyxiation. The preference for using f.c.c. metals at low temperatures is explained in terms of their superior toughness. The limitations on the use of ferritic steels is also considered. Nonmetallic materials are discussed, mainly in the context of their LOX compatibility and their use in the form of foams and fibers as insulatants, seals, and fiber reinforced composites.

Basic cryogenics and materials. Phase 1

NASA Astrophysics Data System (ADS)

Wigley, D. A.

1985-06-01

The effects of cryogenic temperatures on the mechanical and physical properties of materials are summarized. Heat capacity and thermal conductivity are considered in the context of conservation of liquid nitrogen, thermal stability of the gas stream, and the response time for changes in operating temperature. Particular attention is given to the effects of differential expansion and failure due to thermal fatigue. Factors affecting safety are discussed, including hazards created due to the inadvertent production of liquid oxygen and the physiological effects of exposure to liquid and gaseous nitrogen, such as cold burns and asphyxiation. The preference for using f.c.c. metals at low temperatures is explained in terms of their superior toughness. The limitations on the use of ferritic steels is also considered. Nonmetallic materials are discussed, mainly in the context of their LOX compatibility and their use in the form of foams and fibers as insultants, seals, and fiber reinforced composites.

Temperature-touch interaction: Weber's phenomenon revisited.

PubMed

Stevens, J C; Green, B G

1978-09-01

The six experiments reported here stemmed from Weber's (E. H. Weber, In R. Wagner (Ed.), Handwnörterbuch der Physiologie, 1846. Vol. 3, pp. 481-588) report that cold objects on the forehead feel heavier than warm ones, implying an effect of temperature on the touch modality. The experiments arrived at first-order answers to how temperature, force of stimulation, areal size of stimulation, and body locus might influence the magnitude of touch sensation. Typically, concomitant cooling greatly intensifies touch magnitude as perceived via the forehead and the forearm. Warning has little or no effect via the forehead but gives a significant intensification (less pronounced than that of cooling) on the forearm. When the areal size of the stimulation becomes very small, the intensification effects cannot be reliably demonstrated. The findings are reviewed in the light of what is known about the physiology of the cutaneous nerves.

Neutron Imaging at the Oak Ridge National Laboratory: Application to Biological Research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bilheux, Hassina Z; Cekanova, Maria; Bilheux, Jean-Christophe

2014-01-01

The Oak Ridge National Laboratory Neutron Sciences Directorate (NScD) has recently installed a neutron imaging beamline at the High Flux Isotope Reactor (HFIR) cold guide hall. The CG-1D beamline supports a broad range of user research spanning from engineering to material research, energy storage, additive manufacturing, vehicle technologies, archaeology, biology, and plant physiology. The beamline performance (spatial resolution, field of view, etc.) and its utilization for biological research are presented. The NScD is also considering a proposal to build the VENUS imaging beamline (beam port 10) at the Spallation Neutron Source (SNS). Unlike CG-1D which provides cold neutrons, VENUS willmore » offer a broad range of neutron wavelengths, from epithermal to cold, and enhanced contrast mechanisms. This new capability will also enable the imaging of thicker biological samples than is currently available at CG-1D. A brief overview of the VENUS capability for biological research is discussed.« less

Structure of the cold- and menthol-sensing ion channel TRPM8.

PubMed

Yin, Ying; Wu, Mengyu; Zubcevic, Lejla; Borschel, William F; Lander, Gabriel C; Lee, Seok-Yong

2018-01-12

Transient receptor potential melastatin (TRPM) cation channels are polymodal sensors that are involved in a variety of physiological processes. Within the TRPM family, member 8 (TRPM8) is the primary cold and menthol sensor in humans. We determined the cryo-electron microscopy structure of the full-length TRPM8 from the collared flycatcher at an overall resolution of ~4.1 ångstroms. Our TRPM8 structure reveals a three-layered architecture. The amino-terminal domain with a fold distinct among known TRP structures, together with the carboxyl-terminal region, forms a large two-layered cytosolic ring that extensively interacts with the transmembrane channel layer. The structure suggests that the menthol-binding site is located within the voltage-sensor-like domain and thus provides a structural glimpse of the design principle of the molecular transducer for cold and menthol sensation. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Latitudinal variation of freeze tolerance in intertidal marine snails of the genus Melampus (Gastropoda: Ellobiidae).

PubMed

Dennis, A B; Loomis, S H; Hellberg, M E

2014-01-01

Abstract Low temperatures limit the poleward distribution of many species such that the expansion of geographic range can only be accomplished via evolutionary innovation. We have tested for physiological differences among closely related species to determine whether their poleward latitudinal ranges are limited by tolerance to cold. We measured lower temperature tolerance (LT50) among a group of intertidal pulmonate snails from six congeneric species and nine locales. Differences in tolerance are placed in the context of a molecular phylogeny based on one mitochondrial (cytochrome oxidase subunit I) and two nuclear (histone 3 and a mitochondrial phosphate carrier protein) markers. Temperate species from two separate lineages had significantly lower measures of LT50 than related tropical species. Range differences within the temperate zone, however, were not explained by LT50. These results show that multiple adaptations to cold and freezing may have enabled range expansions out of the tropics in Melampus. However, northern range limits within temperate species are not governed by cold tolerance alone.

Monitoring the Temperature of Tree Seedlings With the Thermochron iButton Data Logger

Treesearch

David S. Gasvoda; Richard W. Tinus; Karen E. Burr; Andy Trent

2002-01-01

Tracking the temperature of tree seedlings from the nursery to the planting site can be the key to evaluating possible physiological causes of morality after seedlings are planted. Seedlings enter and leave nursery storage with easily documented levels of cold hardiness, root growth potential, and general stress tolerance (Burr 1990: Ritchie and Tanaka 1990). The...

Seedling quality tests: chlorophyll fluoresence

Treesearch

Gary Ritchie; Thomas D. Landis

2005-01-01

So far in this series we have discussed the most commonly -used seedling quality tests: root growth potential, cold hardiness, and stress resistance. In this issue, we're going to talk about one of the newest test-chlorophyll fluorescence (CF). The technology for measuring CF has been in place for over 50 years but has been applied to tr?e seedling physiology only...

Field-Based Pre-Cooling for On-Court Tennis Conditioning Training in the Heat

PubMed Central

Duffield, Rob; Bird, Stephen P.; Ballard, Robert J.

2011-01-01

The present study investigated the effects of pre-cooling for on- court, tennis-specific conditioning training in the heat. Eight highly-trained tennis players performed two on-court conditioning sessions in 35°C, 55% Relative Humidity. Sessions were randomised, involved either a pre-cooling or control session, and consisted of 30-min of court- based, tennis movement drills. Pre-cooling involved 20-min of an ice-vest and cold towels to the head/neck and legs, followed by warm-up in a cold compression garment. On-court movement distance was recorded by 1Hz Global Positioning Satellite (GPS) devices, while core temperature, heart rate and perceptual exertion and thermal stress were also recorded throughout the session. Additionally, mass and lower-body peak power during repeated counter-movement jumps were measured before and after each session. No significant performance differences were evident between conditions, although a moderate-large effect (d = 0.7-1.0; p > 0.05) was evident for total (2989 ± 256 v 2870 ± 159m) and high-intensity (805 ± 340 v 629 ± 265m) distance covered following pre-cooling. Further, no significant differences were evident between conditions for rise in core temperature (1.9 ± 0.4 v 2. 2 ± 0.4°C; d > 0.9; p > 0.05), although a significantly smaller change in mass (0.9 ± 0.3 v 1. 3 ± 0.3kg; p < 0.05) was present following pre-cooling. Perceived thermal stress and exertion were significantly lower (d > 1.0; p < 0.05) during the cooling session. Finally, lower-body peak power did not differ between conditions before or after training (d < 0.3; p > 0.05). Conclusions: Despite trends for lowered physiological load and increased distances covered following cooling, the observed responses were not significantly different or as explicit as previously reported laboratory-based pre-cooling research. Key points Pre-cooling did not significantly enhance training performance or reduce physiological load for tennis training in the heat, although trends indicate some benefits for both. Pre-cooling can reduce perceptual strain of on-court tennis training in the heat to improve perceptual load of training sessions. Court-side pre-cooling may not be of sufficient volume to invoke large physiological changes. PMID:24149886

Species-specific physiological response by the cold-water corals Lophelia pertusa and Madrepora oculata to variations within their natural temperature range

NASA Astrophysics Data System (ADS)

Naumann, Malik S.; Orejas, Covadonga; Ferrier-Pagès, Christine

2014-01-01

The scleractinian cold-water corals (CWC) Lophelia pertusa and Madrepora oculata represent two major deep-sea reef-forming species that act as key ecosystem engineers over a wide temperature range, extending from the northern Atlantic (ca. 5-9 °C) to the Mediterranean Sea (ca. 11-13 °C). Recent research suggests that environmental parameters, such as food supply, settling substrate availability or aragonite saturation state may represent important precursors controlling habitat suitability for CWC. However, the effect of one principal environmental factor, temperature, on CWC key physiological processes is still unknown. In order to evaluate this effect on calcification, respiration, and dissolved organic carbon (DOC) net flux, colonies of Mediterranean L. pertusa and M. oculata were acclimated in aquaria to three temperatures (12, 9 and 6 °C), by consecutive decrements of 1 month duration. L. pertusa and M. oculata maintained at Mediterranean control conditions (i.e. 12 °C) displayed constant rates, on average respiring 4.8 and 4.0 μmol O2 cm-2 coral surface area d-1, calcifying 22.3 and 12.3 μmol CaCO3 g-1 skeletal dry weight d-1 and net releasing 2.6 and 3.1 μmol DOC cm-2 coral surface area d-1, respectively. Respiration of L. pertusa was not affected by lowered temperatures, while M. oculata respiration declined significantly (by 48%) when temperature decreased to 9 °C and 6 °C relative to controls. L. pertusa calcification at 9 °C was similar to controls, but decreased significantly (by 58%) at 6 °C. For M. oculata, calcification declined by 41% at 9 °C and by 69% at 6 °C. DOC net flux was similar throughout the experiment for both CWC. These findings reveal species-specific physiological responses by CWC within their natural temperature range. L. pertusa shows thermal acclimation in respiration and calcification, while these mechanisms appear largely absent in M. oculata. Conclusively, species-specific thermal acclimation may significantly affect the occurrence and local abundance of cosmopolitan CWC species, consequently influencing their important role in habitat engineering and ecosystem functioning in various thermal environments.

Cell wall, cell membrane, and volatile metabolism are altered by antioxidant treatment, temperature shifts, and peel necrosis during apple fruit storage.

PubMed

Leisso, Rachel; Buchanan, David; Lee, Jinwook; Mattheis, James; Rudell, David

2013-02-13

The transition from cold storage to ambient temperature alters apple quality through accelerated softening, flavor and color changes, and development of physiological peel disorders, such as superficial scald, in susceptible cultivars. To reveal global metabolism associated with this transition, the 'Granny Smith' peel metabolome was evaluated during storage of 6 months and shelf life periods. Treatment with the antioxidant diphenylamine (DPA) reduced scald, creating a metabolic contrast with untreated fruit, which developed superficial scald. Superficial scald symptoms developed on control fruit after 120 days of storage, and symptoms progressed following transition to ambient-temperature shelf life. The metabolic profile of control and DPA-treated fruit was divergent after 30 days of cold storage due to differing levels of α-farnesene oxidation products, methyl esters, phytosterols, and other compounds potentially associated with chloroplast integrity and oxidative stress response. Hierarchical cluster analysis revealed coregulation within the volatile synthesis pathway including control of the availability of methyl, propyl, ethyl, acetyl, and butyl alcohol and/or acid moieties for ester biosynthesis. Overall, the application of metabolomics techniques lends new insight into physiological processes leading to cell death and ripening processes that affect fruit flavor, appearance, and overall quality.

Regulatory mechanisms of metabolic flexibility in the dark-eyed junco (Junco hyemalis).

PubMed

Stager, Maria; Swanson, David L; Cheviron, Zachary A

2015-03-01

Small temperate birds reversibly modify their aerobic performance to maintain thermoregulatory homeostasis under seasonally changing environmental conditions and these physiological adjustments may be attributable to changes in the expression of genes in the underlying regulatory networks. Here, we report the results of an experimental procedure designed to gain insight into the fundamental mechanisms of metabolic flexibility in the dark-eyed junco (Junco hyemalis). We combined genomic transcriptional profiles with measures of metabolic enzyme activities and whole-animal thermogenic performance from juncos exposed to four 6-week acclimation treatments that varied in temperature (cold, 3°C; warm, 24°C) and photoperiod (short day, 8 h light:16 h dark; long day, 16 h light:8 h dark). Cold-acclimated birds increased thermogenic capacity compared with warm-acclimated birds, and this enhanced performance was associated with upregulation of genes involved in muscle hypertrophy, angiogenesis, and lipid transport and oxidation, as well as with catabolic enzyme activities. These physiological changes occurred over ecologically relevant timescales, suggesting that birds make regulatory adjustments to interacting, hierarchical pathways in order to seasonally enhance thermogenic capacity. © 2015. Published by The Company of Biologists Ltd.

Effect of Extreme Cold Treatment on Morphology and Behavior of Hydrogels and Microgels (Poster Session)

DTIC Science & Technology

2017-08-20

UNCLASSIFIED Effect of Extreme Cold Treatment on Morphology and Behavior of Hydrogels and Microgels BACKGROUND • Stimuli responsive hydrogel systems...particularly for cold weather and Arctic uniforms, • The effect of extreme cold on gel responsiveness however is not well studied • This project seeks...to understand the effect of cold temperature ( down to -80 ° C) on hydrogel and microgel particles properties and response to thermal stimuli • We

Alternatively activated macrophages produce catecholamines to sustain adaptive thermogenesis

PubMed Central

Nguyen, Khoa D.; Qiu, Yifu; Cui, Xiaojin; Goh, Y.P. Sharon; Mwangi, Julia; David, Tovo; Mukundan, Lata; Brombacher, Frank; Locksley, Richard M.; Chawla, Ajay

2011-01-01

All homeotherms utilize thermogenesis to maintain core body temperature, ensuring that cellular functions and physiologic processes can ensue in cold environments1-3. In the prevailing model, when the hypothalamus senses cold temperatures, it triggers sympathetic discharge, resulting in the release of noradrenaline in brown adipose tissue (BAT) and white adipose tissue (WAT)4,5. Acting via the β3-adrenergic receptors, noradrenaline induces lipolysis in white adipocytes6, whereas it stimulates the expression of thermogenic genes, such as PPARγ coactivator 1a (Ppargc1a), uncoupling protein 1 (Ucp1), and acyl-CoA synthetase long-chain family member 1 (Acsl1), in brown adipocytes7-9. However, the precise nature of all the cell types involved in this efferent loop is not well established. Here we report an unexpected requirement for the interleukin 4 (IL4)-stimulated program of alternative macrophage activation in adaptive thermogenesis. Cold exposure rapidly promoted alternative activation of adipose tissue macrophages, which secrete catecholamines to induce thermogenic gene expression in BAT and lipolysis in WAT. Absence of alternatively activated macrophages impaired metabolic adaptations to cold, whereas administration of IL4 increased thermogenic gene expression, fatty acid mobilization, and energy expenditure, all in a macrophage-dependent manner. We have thus discovered a surprising role for alternatively activated macrophages in the orchestration of an important mammalian stress response, the response to cold. PMID:22101429

The Nuclear Receptor Rev-erbα Controls Circadian Thermogenic Plasticity

PubMed Central

Gerhart-Hines, Zachary; Everett, Logan J.; Loro, Emanuele; Briggs, Erika R.; Bugge, Anne; Hou, Catherine; Ferrara, Christine; Seale, Patrick; Pryma, Daniel A.; Khurana, Tejvir S.; Lazar, Mitchell A.

2013-01-01

Circadian oscillation of body temperature is a basic, evolutionary-conserved feature of mammalian biology1. Additionally, homeostatic pathways allow organisms to protect their core temperatures in response to cold exposure2. However, the mechanism responsible for coordinating daily body temperature rhythm and adaptability to environmental challenges is unknown. Here we show that the nuclear receptor Rev-erbα, a powerful transcriptional repressor, links circadian and thermogenic networks through the regulation of brown adipose tissue (BAT) function. Mice exposed to cold fare dramatically better at 5 AM (Zeitgeber time 22) when Rev-erbα is barely expressed than at 5 PM (ZT10) when Rev-erbα is abundant. Deletion of Rev-erbα markedly improves cold tolerance at 5 PM, indicating that overcoming Rev-erbα-dependent repression is a fundamental feature of the thermogenic response to cold. Physiological induction of uncoupling protein 1 (UCP1) by cold temperatures is preceded by rapid down-regulation of Rev-erbα in BAT. Rev-erbα represses UCP1 in a brown adipose cell-autonomous manner and BAT UCP1 levels are high in Rev-erbα-null mice even at thermoneutrality. Genetic loss of Rev-erbα also abolishes normal rhythms of body temperature and BAT activity. Thus, Rev-erbα acts as a thermogenic focal point required for establishing and maintaining body temperature rhythm in a manner that is adaptable to environmental demands. PMID:24162845

Impact of prenatal cold stress on placental physiology, inflammatory response, and apoptosis in rats.

PubMed

Lian, Shuai; Guo, Jingru; Wang, Lipeng; Li, Wenjie; Wang, Jianfa; Ji, Hong; Kong, Fanzhi; Xu, Bin; Li, Shize; Yang, Huanmin

2017-12-29

Prenatal cold stress is one of the earliest factors affecting mammalian health, and is associated with neonatal growth retardation and immune dysfunction, thus increasing disease susceptibility. The mechanisms underlying these observations remain unclear; hence, the objective of this study was to elucidate placental responses to cold stress. 60 maternal rats were randomly allocated to either stressed (n = 30) or non-stressed (control, n = 30) treatment conditions and 30 pubs (n=15) were used for the pups analysis. We found that maternal exposure to cold stress resulted in decreased body temperature, increased food intake without body weight gain, and a high level of plasma corticosterone (CORT) between gestational day (GD) 14 and GD21. In addition, gestation cold stress induced the placental expression of heat shock protein 70 (HSP70), IκBα, glucocorticoid receptor (GR), mineralocorticoid receptor (MR), 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2), interferon (IFN) regulatory factor 3 (IRF3), Caspase-3 proteins and altered the ratio of B-cell lymphoma-extra large (Bcl-xL) to Bcl-associated x (Bax) proteins on gestational GD15, GD17, GD19, and GD21, also resulted in the production of interleukin (IL)-1β. Next, gestational cold stress provoked a decrease in plasma GH levels of 21-day-old offspring, and the body weights of offspring were have no differences from postnatal day (PD) 1-21. Taken together, our results indicate that gestational cold stress induces placental apoptosis and the activation of NF-kB via HSP70/TLR4/NF-κB signaling pathways in the placenta, these changes may affect placental function and fetus development.

Leaves of the Arabidopsis maltose exporter1 Mutant Exhibit a Metabolic Profile with Features of Cold Acclimation in the Warm

PubMed Central

Purdy, Sarah J.; Bussell, John D.; Nunn, Christopher P.; Smith, Steven M.

2013-01-01

Background Arabidopsis plants accumulate maltose from starch breakdown during cold acclimation. The Arabidopsis mutant, maltose excess1-1, accumulates large amounts of maltose in the plastid even in the warm, due to a deficient plastid envelope maltose transporter. We therefore investigated whether the elevated maltose level in mex1-1 in the warm could result in changes in metabolism and physiology typical of WT plants grown in the cold. Principal Findings Grown at 21 °C, mex1-1 plants were much smaller, with fewer leaves, and elevated carbohydrates and amino acids compared to WT. However, after transfer to 4 °C the total soluble sugar pool and amino acid concentration was in equal abundance in both genotypes, although the most abundant sugar in mex1-1 was still maltose whereas sucrose was in greatest abundance in WT. The chlorophyll a/b ratio in WT was much lower in the cold than in the warm, but in mex1-1 it was low in both warm and cold. After prolonged growth at 4 °C, the shoot biomass, rosette diameter and number of leaves at bolting were similar in mex1-1 and WT. Conclusions The mex1-1 mutation in warm-grown plants confers aspects of cold acclimation, including elevated levels of sugars and amino acids and low chlorophyll a/b ratio. This may in turn compromise growth of mex1-1 in the warm relative to WT. We suggest that elevated maltose in the plastid could be responsible for key aspects of cold acclimation. PMID:24223944

Seed Heteromorphism and Effects of Light and Abiotic Stress on Germination of a Typical Annual Halophyte Salsola ferganica in Cold Desert

PubMed Central

Ma, Yali; Wang, Juan; Zhang, Jinghua; Zhang, Shiyue; Liu, Yanxia; Lan, Haiyan

2018-01-01

Seed heteromorphism is a common characteristic of halophyte and an adaptation to the spatial and temporal variations of natural habitats. Differences in dormancy and germination requirements have been documented in heteromorphic seeds of many species, but the mechanisms for maintenance between different status in various populations have not been well-understood. Salsola ferganica is a typical annual halophyte in Chenopodiaceae distributed in cold desert, in the present study, we found that it could produce three distinct types of seed according to the shape and size of winged perianth (WP), which differed in dispersal ability, dormancy and germination behaviors. Our further investigation revealed that light could significantly promote germination of heteromorphic seeds of S. ferganica, and WP inhibited while GA3 enhanced germination, which suggests that S. ferganica seeds possessed a photo-sensitive combined with morphological and non-deep physiological dormancy type, in which light was the dominant factor. Not like other desert plant species, the germinability of heteromorphic seeds of S. ferganica could not sustain for long (only 1–2 years), especially the small seeds, and was affected by storage time, temperature, salinity, even the environmental conditions of the maternal plant. Thus, the differences of characteristics existed among heteromorphic seeds and variations of heteromorphic ratio among different calendar years were presumed as diverse adaptation strategies integrated in the individual mother plant, and might apply important ecological significance for successful reproduction of the species in the unpredictable cold desert. PMID:29387073

Sex-Dependent Effects Of Cannabis-Induced Analgesia

PubMed Central

Cooper, Ziva D.; Haney, Margaret

2016-01-01

Background Preclinical studies demonstrate that cannabinoid-mediated antinociceptive effects vary according to sex; it is unknown if these findings extend to humans. Methods This retrospective analysis compared the analgesic, subjective and physiological effects of active cannabis (3.56 - 5.60% THC) and inactive cannabis (0.00% THC) in male (N = 21) and female (N = 21) cannabis smokers under double-blind, placebo-controlled conditions. Pain response was measured using the Cold-Pressor Test (CPT). Participants immersed their hand in cold water (4°C); times to report pain (pain sensitivity) and withdraw the hand (pain tolerance) were recorded. Subjective drug ratings were also measured. Results Among men, active cannabis significantly decreased pain sensitivity relative to inactive cannabis (p < 0.01). In women, active cannabis failed to decrease pain sensitivity relative to inactive. Active cannabis increased pain tolerance in both men women immediately after smoking (p < 0.001); a trend was observed for differences between men and women (p < 0.10). Active cannabis also increased subjective ratings of cannabis associated with abuse liability (‘Take again,’ ‘Liking,’ ‘Good drug effect’), drug strength, and ‘High’ relative to inactive in both men and women (p < 0.01). Conclusions These results indicate that in cannabis smokers, men exhibit greater cannabis-induced analgesia relative to women. These sex-dependent differences are independent of cannabis-elicited subjective effects associated with abuse-liability, which were consistent between men and women. As such, sex-dependent differences in cannabis's analgesic effects are an important consideration that warrants further investigation when considering the potential therapeutic effects of cannabinoids for pain relief. PMID:27522535

Phenotypic plasticity in the range-margin population of the lycaenid butterfly Zizeeria maha

PubMed Central

2010-01-01

Background Many butterfly species have been experiencing the northward range expansion and physiological adaptation, probably due to climate warming. Here, we document an extraordinary field case of a species of lycaenid butterfly, Zizeeria maha, for which plastic phenotypes of wing color-patterns were revealed at the population level in the course of range expansion. Furthermore, we examined whether this outbreak of phenotypic changes was able to be reproduced in a laboratory. Results In the recently expanded northern range margins of this species, more than 10% of the Z. maha population exhibited characteristic color-pattern modifications on the ventral wings for three years. We physiologically reproduced similar phenotypes by an artificial cold-shock treatment of a normal southern population, and furthermore, we genetically reproduced a similar phenotype after selective breeding of a normal population for ten generations, demonstrating that the cold-shock-induced phenotype was heritable and partially assimilated genetically in the breeding line. Similar genetic process might have occurred in the previous and recent range-margin populations as well. Relatively minor modifications expressed in the tenth generation of the breeding line together with other data suggest a role of founder effect in this field case. Conclusions Our results support the notion that the outbreak of the modified phenotypes in the recent range-margin population was primed by the revelation of plastic phenotypes in response to temperature stress and by the subsequent genetic process in the previous range-margin population, followed by migration and temporal establishment of genetically unstable founders in the recent range margins. This case presents not only an evolutionary role of phenotypic plasticity in the field but also a novel evolutionary aspect of range expansion at the species level. PMID:20718993

Cryptococcus vaughanmartiniae sp. nov. and Cryptococcus onofrii sp. nov.: two new species isolated from worldwide cold environments.

PubMed

Turchetti, Benedetta; Selbmann, Laura; Blanchette, Robert A; Di Mauro, Simone; Marchegiani, Elisabetta; Zucconi, Laura; Arenz, Brett E; Buzzini, Pietro

2015-01-01

Twenty yeast strains, representing a selection from a wider group of more than 60 isolates were isolated from cold environments worldwide (Antarctica, Iceland, Russia, USA, Italian and French Alps, Apennines). The strains were grouped based on their common morphological and physiological characteristics. A phylogeny based on D1/D2 ribosomal DNA sequences placed them in an intermediate position between Cryptococcus saitoi and Cryptococcus friedmannii; the ITS1 and ITS2 rDNA phylogeny demonstrated that these strains belong to two related but hitherto unknown species within the order Filobasidiales, albidus clade. These two novel species are described with the names Cryptococcus vaughanmartiniae (type strain DBVPG 4736(T)) and Cryptococcus onofrii (type strain DBVPG 5303(T)).

Mountain Warfare and Cold Weather Operations

DTIC Science & Technology

2016-04-29

military purposes, cold regions are defined as any region where cold temperatures , unique terrain, and snowfall have a significant effect on military...because of the wind’s effect on the body’s perceived temperature . Wet cold leads to hypothermia, frost bite, and trench foot. Wet cold conditions are...combined cooling effect of ambient temperature and wind (wind chill) experienced by their troops (see Figure 1-5). The Environment ATP 3-90.97

The perspective effects of various seed coating substances on rice seed variety Khao DAWK Mali 105 storability I: the case study of physiological properties.

PubMed

Thobunluepop, P; Pawelzik, E; Vearasilp, S

2008-10-01

This study aimed to evaluate the perspective changes of several physiological performances of rice seeds cv. KDML 105 which were coated with various seed coating substances [chemical fungicide, captan (CA) and biological coating polymers; chitosan-lignosulphonate polymer (CL) and eugenol incorporated into chitosan-lignosulphonate polymer (E + CL)] during storage (12 months). CA significantly increased seed moisture content and seed water activity through out the storage period. The qualities and viability of the seeds were seriously declined by this treatment. Moreover, CA inhibited the shoot and root development, seedling dry weight accumulation, delayed the seed germination and seedling growth rate. CA treated seeds were susceptible to stress conditions that declined the seed germination potential under cold, high moisture and temperature stress conditions. Nevertheless, CL and E + CL coating polymer could maintain seed storability, which significantly improved seed germination and seedling performances. These improvements were attributed to maintain the nutritive reserve and dehydrogenase activity in seeds. Moreover, the biological seed treatment stimulated the embryo growth and so speeding up the seedling emergence when compared untreated seeds.

Characteristics and physiological role of hyperpolarization activated currents in mouse cold thermoreceptors

PubMed Central

Orio, Patricio; Madrid, Rodolfo; de la Peña, Elvira; Parra, Andrés; Meseguer, Víctor; Bayliss, Douglas A; Belmonte, Carlos; Viana, Félix

2009-01-01

Hyperpolarization-activated currents (Ih) are mediated by the expression of combinations of hyperpolarization-activated, cyclic nucleotide-gated (HCN) channel subunits (HCN1–4). These cation currents are key regulators of cellular excitability in the heart and many neurons in the nervous system. Subunit composition determines the gating properties and cAMP sensitivity of native Ih currents. We investigated the functional properties of Ih in adult mouse cold thermoreceptor neurons from the trigeminal ganglion, identified by their high sensitivity to moderate cooling and responsiveness to menthol. All cultured cold-sensitive (CS) neurons expressed a fast activating Ih, which was fully blocked by extracellular Cs+ or ZD7288 and had biophysical properties consistent with those of heteromeric HCN1–HCN2 channels. In CS neurons from HCN1(−/−) animals, Ih was greatly reduced but not abolished. We find that Ih activity is not essential for the transduction of cold stimuli in CS neurons. Nevertheless, Ih has the potential to shape the excitability of CS neurons. First, Ih blockade caused a membrane hyperpolarization in CS neurons of about 5 mV. Furthermore, impedance power analysis showed that all CS neurons had a prominent subthreshold membrane resonance in the 5–7 Hz range, completely abolished upon blockade of Ih and absent in HCN1 null mice. This frequency range matches the spontaneous firing frequency of cold thermoreceptor terminals in vivo. Behavioural responses to cooling were reduced in HCN1 null mice and after peripheral pharmacological blockade of Ih with ZD7288, suggesting that Ih plays an important role in peripheral sensitivity to cold. PMID:19273581

Transcriptomic characterization of temperature stress responses in larval zebrafish.

PubMed

Long, Yong; Li, Linchun; Li, Qing; He, Xiaozhen; Cui, Zongbin

2012-01-01

Temperature influences nearly all biochemical, physiological and life history activities of fish, but the molecular mechanisms underlying the temperature acclimation remains largely unknown. Previous studies have identified many temperature-regulated genes in adult tissues; however, the transcriptional responses of fish larvae to temperature stress are not well understood. In this study, we characterized the transcriptional responses in larval zebrafish exposed to cold or heat stress using microarray analysis. In comparison with genes expressed in the control at 28 °C, a total of 2680 genes were found to be affected in 96 hpf larvae exposed to cold (16 °C) or heat (34 °C) for 2 and 48h and most of these genes were expressed in a temperature-specific and temporally regulated manner. Bioinformatic analysis identified multiple temperature-regulated biological processes and pathways. Biological processes overrepresented among the earliest genes induced by temperature stress include regulation of transcription, nucleosome assembly, chromatin organization and protein folding. However, processes such as RNA processing, cellular metal ion homeostasis and protein transport and were enriched in genes up-regulated under cold exposure for 48 h. Pathways such as mTOR signalling, p53 signalling and circadian rhythm were enriched among cold-induced genes, while adipocytokine signalling, protein export and arginine and praline metabolism were enriched among heat-induced genes. Although most of these biological processes and pathways were specifically regulated by cold or heat, common responses to both cold and heat stresses were also found. Thus, these findings provide new interesting clues for elucidation of mechanisms underlying the temperature acclimation in fish.

Acute responses of American kestrels to methyl parathion and fenvalerate

USGS Publications Warehouse

Rattner, B.A.; Franson, J.C.

1984-01-01

Physiological and toxicological effects of p.o, methyl parathion (0.375-3.0 mg/kg) or fenvalerate (1000-4000 mg/kg) were examined over a 10 h period in American kestrels (Falco sparverius) maintained in thermoneutral (22?.C) and cold (-5?.C) environments. Methyl parathion was highly toxic (LD50=3.08 mg/kg, 95% confidence limits=2.29-4.l4 mg/kg, producing overt intoxication (abnormal posture, ataxia, paresis), dose-dependent inhibition (26-67%) of brain acetylcholinesterase activity, hyperglycemia, and elevated plasma corticosterone concentration. Transient but pronounced hypothermia was associated with plasma cholinesterase inhibition in excess of 50% (2 h after intubation), although this response was highly variable (plasma ChE inhibition vs. A cloacal temperature, r=-0.60). Fenvalerate, at doses far exceeding those encountered in the environment, caused mild intoxication (irregular head movement) and elevated plasma alanine aminotransferase activity, but did not alter cloacal temperature, plasma activities of CK, U-HBDH, and LDK, or concentrations of corticosterone, glucose, triiodothyronine, and uric acid. Cold exposure intensified methyl parathion toxicity, but did not affect that of fenvalerate. It would thus appear that the organophosphorus insecticide methyl parathion poses far greater hazard than the pyrethroid fenvalerate to raptorial birds.

Afferent thermosensory function in relapsing-remitting multiple sclerosis following exercise-induced increases in body temperature.

PubMed

Filingeri, Davide; Chaseling, Georgia; Hoang, Phu; Barnett, Michael; Davis, Scott L; Jay, Ollie

2017-08-01

What is the central question of this study? Between 60 and 80% of multiple sclerosis (MS) patients experience transient worsening of symptoms with increased body temperature (heat sensitivity). As sensory abnormalities are common in MS, we asked whether afferent thermosensory function is altered in MS following exercise-induced increases in body temperature. What is the main finding and its importance? Increases in body temperature of as little as ∼0.4°C were sufficient to decrease cold, but not warm, skin thermosensitivity (∼10%) in MS, across a wider temperature range than in age-matched healthy individuals. These findings provide new evidence on the impact of heat sensitivity on afferent function in MS, which could be useful for clinical evaluation of this neurological disease. In multiple sclerosis (MS), increases in body temperature result in transient worsening of clinical symptoms (heat sensitivity or Uhthoff's phenomenon). Although the impact of heat sensitivity on efferent physiological function has been investigated, the effects of heat stress on afferent sensory function in MS are unknown. Hence, we quantified afferent thermosensory function in MS following exercise-induced increases in body temperature with a new quantitative sensory test. Eight relapsing-remitting MS patients (three men and five women; 51.4 ± 9.1 years of age; Expanded Disability Status Scale score 2.8 ± 1.1) and eight age-matched control (CTR) subjects (five men and three women; 47.4 ± 9.1 years of age) rated the perceived magnitude of two cold (26 and 22°C) and two warm stimuli (34 and 38°C) applied to the dorsum of the hand before and after 30 min cycling in the heat (30°C air; 30% relative humidity). Exercise produced similar increases in mean body temperature in MS [+0.39°C (95% CI: +0.21, +0.53) P = 0.001] and CTR subjects [+0.41°C (95% CI: +0.25, +0.58) P = 0.001]. These changes were sufficient to decrease thermosensitivity significantly to all cold [26°C stimulus, -9.1% (95% CI: -17.0, -1.5), P = 0.006; 22°C stimulus, -10.6% (95% CI: -17.3, -3.7), P = 0.027], but not warm, stimuli in MS. Contrariwise, CTR subjects showed sensitivity reductions to colder stimuli only [22°C stimulus, -9.7% (95% CI: -16.4, -3.1), P = 0.011]. The observation that reductions in thermal sensitivity in MS were confined to the myelinated cold-sensitive pathway and extended across a wider (including milder and colder) temperature range than what is observed in CTR subjects provides new evidence on the impact of rising body temperature on afferent neural function in MS. Also, our findings support the use of our new approach to investigate afferent sensory function in MS during heat stress. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

Energy Homeostasis in Monotremes

PubMed Central

Nicol, Stewart C.

2017-01-01

In 1803, the French anatomist Étienne Geoffroy Saint-Hilaire decided that the newly described echidna and platypus should be placed in a separate order, the monotremes, intermediate between reptiles and mammals. The first physiological observations showed monotremes had low body temperatures and metabolic rates, and the consensus was that they were at a stage of physiological development intermediate between “higher mammals” and “lower vertebrates.” Subsequent studies demonstrated that platypuses and echidnas are capable of close thermoregulation in the cold although less so under hot conditions. Because the short-beaked echidna Tachyglossus aculeatus, may show very large daily variations in body temperature, as well as seasonal hibernation, it has been suggested that it may provide a useful model of protoendotherm physiology. Such analysis is complicated by the very significant differences in thermal relations between echidnas from different climates. In all areas female echidnas regulate Tb within 1°C during egg incubation. The lactation period is considered to be the most energetically expensive time for most female mammals but lactating echidnas showed no measurable difference in field metabolic rate from non-lactating females, while the lactation period is more than 200 days for Kangaroo Island echidnas but only 150 days in Tasmania. In areas with mild winters echidnas show reduced activity and shallow torpor in autumn and early winter, but in areas with cold winters echidnas enter true hibernation with Tb falling as low as 4.5°C. Monotremes do not possess brown adipose tissue and maximum rates of rewarming from hibernation in echidnas were only half those of marmots of the same mass. Although echidnas show very large seasonal variations in fat stores associated with hibernation there is no relationship between plasma leptin and adiposity. Leptin levels are lowest during post-reproductive fattening, supporting suggestions that in evolutionary terms the anorectic effects of leptin preceded the adiposity signal. BMR of platypuses is twice that of echidnas although maximum metabolism is similar. High levels of thyroid hormones in platypuses may be driving metabolism limited by low body temperature. Monotremes show a mosaic of plesiomorphic and derived features but can still inform our understanding of the evolution of endothermy. PMID:28484364

Physiological and biochemical characteristics of adrenergic receptors and pathways in brown adipocytes

NASA Technical Reports Server (NTRS)

Horwitz, B. A.

1975-01-01

Mechanisms involved in the thermogenic response of brown adipose tissue (BAT) to sympathetic nervous stimulation (e.g., by cold exposure) and to norepinephrine (NE) release are investigated. Three effects appear to play a role in the increased oxygen consumption (and heat production) of the adipocytes: increased membrane permeability, activation of the beta-adrenergic pathway, and enhancement of Na(+)/K(+) membrane pump activity. Increased passive influx of Na(+) and efflux of K(+) due to greater permeability raise the energy demands of the Na/K pump; the pump is also stimulated by increased cyclic AMP synthesis resulting from activation by NE of membrane-bound adenyl cyclase. Studies with inhibitors such as propanolol, phentolamine, and ouabain support this hypothesis.

The utilization of infrared imaging for occupational disease study in industrial work.

PubMed

Brioschi, Marcos Leal; Okimoto, Maria Lúcia Leite Ribeiro; Vargas, José Viriato Coelho

2012-01-01

Infrared imaging has been used to visualize superficial temperatures in industrial employers standing and working in an indoor environment at 22°C. Temperature distributions and changes have been recorded digitally and analyzed. Mean skin temperatures determined by this method have been compared with superficial temperatures obtained with a probe thermocouple. During working hours, surface temperatures were higher over extensor muscles than over other structures and their spatial distributions differed dramatically from those observed before working hours. The authors also analyzed the cold water immersion of the hands during work. This paper showed that working generates different thermal effects on human skin that reflect physiological and pathological occupational conditions and can be monitored by infrared imaging.

Using electrolyte leakage tests to determine lifting windows and detect tissue damage

Treesearch

Richard W. Tinus

2002-01-01

Physiological testing is rapidly coming into use as a means to determine the condition of nursery stock and predict how it will respond to treatment or use. One such test, the electrolyte leakage test, can be used to measure cold hardiness and detect tissue damage. The principle of this test is that when cell membranes are damaged, electrolytes leak out into the water...

Measurement of Coronary-Prone Behavior and Autonomic Reactivity.

DTIC Science & Technology

1981-05-01

function or emotionality, suggests a three-factor model: a general autonomic e:tivity factor identical with anxiety and two other autonomic activity...alerting response may be an example of Cattell’s general anxiety factor. Other studies have focused on similarities of physiological responses across...approach. Zuckerman et al. (81) examined the relationships amon: anxiety , depression, hostility, GSR, heart rate, and breathing during a cold pressor

Evaluation of Physiological and Psychological Impairment of Human Performance in Cold Stressed Subjects

DTIC Science & Technology

1990-03-23

defined (personal communciation between R. Pozos and Simon, 1985). In summary, there have been studies dealing with shivering which indicate that the...microcomputer (IBM PS/2, Model 30/286). The Firearms Training System combines features of several technologies, notably: interactive video-disc/ computer ...technology and laser designator/camera/ computer /target-hit generation, which provides for immediate visual performance feedback. The subject is

Life-stage-specific physiology defines invasion extent of a riverine fish

USGS Publications Warehouse

Lawrence, David J.; Beauchamp, David A.; Olden, Julian D.

2015-01-01

Many ecologists have called for mechanism-based investigations to identify the underlying controls on species distributions. Understanding these controls can be especially useful to construct robust predictions of how a species range may change in response to climate change or the extent to which a non-native species may spread in novel environments.Here, we link spatially intensive observations with mechanistic models to illustrate how physiology determines the upstream extent of the aquatic ectotherm smallmouth bass (Micropterus dolomieu) in two headwater rivers.Our results demonstrate that as temperatures become increasingly cold across a downstream to upstream gradient, food consumption in age 0 bass becomes increasingly constrained, and as a result, these fish become growth limited. Sufficient first summer growth of age 0 bass is essential for overwinter survival because young bass must persist from energy reserves accumulated during the summer, and those reserves are determined by body size.Our field data reveal the upstream extent of adult bass reproduction corresponds to a point in the downstream/upstream gradient where cold temperatures impair growth opportunities in young bass. This pattern was repeated in both study streams and explained why bass positioned nests twice as far upstream in the warm compared to the cold stream in the same basin. Placement of spawning nests by adult bass is likely subject to strong evolutionary selection in temperate systems: if bass spawn too far upstream, their young are unlikely to grow large enough to survive the winter. Consumption and growth in older bass (age 3–4) was far less sensitive to temperature. Based on these data, we suggest that temperature-sensitive age 0 bass constrain the upstream distribution limits of bass within temperate streams.In this study, we investigated how temperature-dependent physiology changed through the life history of a species and, in doing so, identified a climate-sensitive life-history stage that likely sets the distributional limits of all other life-history stages. We anticipate the framework developed here could be employed to identify how similar stage-specific environmental sensitivity determines distribution in many other ectothermic species.

Effects of cold water immersion and active recovery on hemodynamics and recovery of muscle strength following resistance exercise.

PubMed

Roberts, Llion A; Muthalib, Makii; Stanley, Jamie; Lichtwark, Glen; Nosaka, Kazunori; Coombes, Jeff S; Peake, Jonathan M

2015-08-15

Cold water immersion (CWI) and active recovery (ACT) are frequently used as postexercise recovery strategies. However, the physiological effects of CWI and ACT after resistance exercise are not well characterized. We examined the effects of CWI and ACT on cardiac output (Q̇), muscle oxygenation (SmO2), blood volume (tHb), muscle temperature (Tmuscle), and isometric strength after resistance exercise. On separate days, 10 men performed resistance exercise, followed by 10 min CWI at 10°C or 10 min ACT (low-intensity cycling). Q̇ (7.9 ± 2.7 l) and Tmuscle (2.2 ± 0.8°C) increased, whereas SmO2 (-21.5 ± 8.8%) and tHb (-10.1 ± 7.7 μM) decreased after exercise (P < 0.05). During CWI, Q̇ (-1.1 ± 0.7 l) and Tmuscle (-6.6 ± 5.3°C) decreased, while tHb (121 ± 77 μM) increased (P < 0.05). In the hour after CWI, Q̇ and Tmuscle remained low, while tHb also decreased (P < 0.05). By contrast, during ACT, Q̇ (3.9 ± 2.3 l), Tmuscle (2.2 ± 0.5°C), SmO2 (17.1 ± 5.7%), and tHb (91 ± 66 μM) all increased (P < 0.05). In the hour after ACT, Tmuscle, and tHb remained high (P < 0.05). Peak isometric strength during 10-s maximum voluntary contractions (MVCs) did not change significantly after CWI, whereas it decreased after ACT (-30 to -45 Nm; P < 0.05). Muscle deoxygenation time during MVCs increased after ACT (P < 0.05), but not after CWI. Muscle reoxygenation time after MVCs tended to increase after CWI (P = 0.052). These findings suggest first that hemodynamics and muscle temperature after resistance exercise are dependent on ambient temperature and metabolic demands with skeletal muscle, and second, that recovery of strength after resistance exercise is independent of changes in hemodynamics and muscle temperature. Copyright © 2015 the American Physiological Society.

The Influence of Cold Temperature on Cellular Excitability of Hippocampal Networks

PubMed Central

Vara, Hugo; Caires, Rebeca; Ballesta, Juan J.; Belmonte, Carlos; Viana, Felix

2012-01-01

The hippocampus plays an important role in short term memory, learning and spatial navigation. A characteristic feature of the hippocampal region is its expression of different electrical population rhythms and activities during different brain states. Physiological fluctuations in brain temperature affect the activity patterns in hippocampus, but the underlying cellular mechanisms are poorly understood. In this work, we investigated the thermal modulation of hippocampal activity at the cellular network level. Primary cell cultures of mouse E17 hippocampus displayed robust network activation upon light cooling of the extracellular solution from baseline physiological temperatures. The activity generated was dependent on action potential firing and excitatory glutamatergic synaptic transmission. Involvement of thermosensitive channels from the transient receptor potential (TRP) family in network activation by temperature changes was ruled out, whereas pharmacological and immunochemical experiments strongly pointed towards the involvement of temperature-sensitive two-pore-domain potassium channels (K2P), TREK/TRAAK family. In hippocampal slices we could show an increase in evoked and spontaneous synaptic activity produced by mild cooling in the physiological range that was prevented by chloroform, a K2P channel opener. We propose that cold-induced closure of background TREK/TRAAK family channels increases the excitability of some hippocampal neurons, acting as a temperature-sensitive gate of network activation. Our findings in the hippocampus open the possibility that small temperature variations in the brain in vivo, associated with metabolism or blood flow oscillations, act as a switch mechanism of neuronal activity and determination of firing patterns through regulation of thermosensitive background potassium channel activity. PMID:23300680

The complementary and divergent roles of uncoupling proteins 1 and 3 in thermoregulation

PubMed Central

Riley, Christopher L.; Dao, Christine; Kenaston, M. Alexander; Muto, Luigina; Kohno, Shohei; Nowinski, Sara M.; Solmonson, Ashley D.; Pfeiffer, Matthew; Sack, Michael N.; Lu, Zhongping; Fiermonte, Giuseppe; Sprague, Jon E.

2016-01-01

Key points Both uncoupling protein 1 (UCP1) and UCP3 are important for mammalian thermoregulation.UCP1 and UCP3 in brown adipose tissue mediate early and late phases of sympathomimetic thermogenesis, respectively.Lipopolysaccharide thermogenesis requires skeletal muscle UCP3 but not UCP1.Acute noradrenaline‐induced hyperthermia requires UCP1 but not UCP3.Loss of both UCP1 and UCP3 accelerate the loss of body temperature compared to UCP1KO alone during acute cold exposure. Abstract Uncoupling protein 1 (UCP1) is the established mediator of brown adipose tissue‐dependent thermogenesis. In contrast, the role of UCP3, expressed in both skeletal muscle and brown adipose tissue, in thermoregulatory physiology is less well understood. Here, we show that mice lacking UCP3 (UCP3KO) have impaired sympathomimetic (methamphetamine) and completely abrogated lipopolysaccharide (LPS) thermogenesis, but a normal response to noradrenaline. By comparison, UCP1 knockout (UCP1KO) mice exhibit blunted methamphetamine and fully inhibited noradrenaline thermogenesis, but an increased febrile response to LPS. We further establish that mice lacking both UCP1 and 3 (UCPDK) fail to show methamphetamine‐induced hyperthermia, and have a markedly accelerated loss of body temperature and survival after cold exposure compared to UCP1KO mice. Finally, we show that skeletal muscle‐specific human UCP3 expression is able to significantly rescue LPS, but not sympathomimetic thermogenesis blunted in UCP3KO mice. These studies identify UCP3 as an important mediator of physiological thermogenesis and support a renewed focus on targeting UCP3 in metabolic physiology. PMID:27647490

Association of cold temperature and mortality and effect modification in the subtropical plateau monsoon climate of Yuxi, China.

PubMed

Ding, Zan; Li, Liujiu; Wei, Ruqin; Dong, Wenya; Guo, Pi; Yang, Shaoyi; Liu, Ju; Zhang, Qingying

2016-10-01

Consistent evidence has shown excess mortality associated with cold temperature, but some important details of the cold-mortality association (e.g. slope and threshold) have not been adequately investigated and few studies focused on the cold effect in high-altitude areas of developing countries. We attempted to quantify the cold effect on mortality, identify the details, and evaluate effect modification in the distinct subtropical plateau monsoon climate of Yuxi, a high plateau region in southwest China. From daily mortality and meteorological data during 2009-2014, we used a quasi-Poisson model combined with a "natural cubic spline-natural cubic spline" distributed lag non-linear model to estimate the temperature-mortality relationship and then a simpler "hockey-stick" model to investigate the cold effect and details. Cold temperature was associated with increased mortality, and the relative risk of cold effect (1st relative to 10th temperature percentile) on non-accidental, cardiovascular, and respiratory mortality for lag 0-21 days was 1.40 (95% confidence interval: 1.19-1.66), 1.61 (1.28-2.02), and 1.13 (0.78-1.64), respectively. A 1°C decrease below a cold threshold of 9.1°C (8th percentile) for lags 0-21 was associated with a 7.35% (3.75-11.09%) increase in non-accidental mortality. The cold-mortality association was not significantly affected by cause-specific mortality, gender, age, marital status, ethnicity, occupation, or previous history of hypertension. There is an adverse impact of cold on mortality in Yuxi, China, and a temperature of 9.1°C is an important cut-off for cold-related mortality for residents. Copyright © 2016 Elsevier Inc. All rights reserved.

Night-shift work is associated with increased pain perception.

PubMed

Matre, Dagfinn; Knardahl, Stein; Nilsen, Kristian Bernhard

2017-05-01

Objectives The aim of the present study was to determine whether shift workers exhibit increased perception of experimentally induced pain after working night shifts. Methods The study was a paired cross-over design with two sleep conditions, after at least two nights of habitual sleep and after two consecutive night shifts at work. Fifty-three nurses in rotating shift work participated. The sensitivity to electrically induced pain, heat pain, cold pain, pressure pain and pain inhibition was determined experimentally in each sleep condition. Sleepiness and vigilance were also assessed. Results Night-shift work (NSW) increased the sensitivity to electrically induced pain and heat pain (P≤0.001). Relative to habitual sleep, electrically induced pain increased by 22.3% and heat pain increased by 26.5%. The sensitivity to cold and pressure pain did not change, changes relative to habitual sleep was <5% (P>0.5). Pain inhibition was 66.9% stronger after NSW versus after habitual sleep (P<0.001). Sleepiness (measured with the Karolinska Sleepiness Scale) increased from 4.1 after habitual sleep to 6.9 after NSW (P<0.001). Vigilance decreased after NSW, measured as a 0.03-second decrease in reaction time (P<0.005). Conclusions Changes in pain sensitivity after NSW is measurable with clinically relevant effect sizes and may be an important marker for studies comparing the physiological effects of different shift work schedules. Explanations for the differential effect on different pain modalities should be a focus for future studies.

Effects of opioid peptides on thermoregulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, W.G.

1981-11-01

In a given species, injected opioid peptides usually cause changes in temperature similar to those caused by nonpeptide opioids. The main effect in those species most studied, the cat, rat, and mouse, is an increase in the level about which body temperature is regulated; there is a coordinated change in the activity of thermoregulatory effectors such that hyperthermia is produced in both hot and cold environments. Larger doses may depress thermoregulation, thereby causing body temperature to decrease in the cold. Elicitation of different patterns of response over a range of environmental temperatures and studies with naloxone and naltrexone indicate thatmore » stimulation of a number of different receptors by both peptide and nonpeptide opioids can evoke thermoregulatory responses. ..beta..-Endorphin is readily antagonized by naloxone whereas methionine-enkephalin can act on naloxone-insensitive receptors. Moreover, synthetic peptide analogs do not necessarily evoke the same response as does the related endogenous peptide. The lack of effect of naloxone on body temperature of subjects housed at usual laboratory temperature or on pyrogen-induced increases in body temperature indicates that an action of endogenous peptides on naloxone-sensitive receptors plays little, if any, role in normal thermoregulation or in fever. However, there is some evidence that such an action may be involved in responses to restraint or ambient temperature-induced stress. Further evaluation of possible physiological roles of endogenous opioid peptides will be facilitated when specific antagonists at other types of opioid receptors become available.« less

Bifidobacterium longum 1714 as a translational psychobiotic: modulation of stress, electrophysiology and neurocognition in healthy volunteers.

PubMed

Allen, A P; Hutch, W; Borre, Y E; Kennedy, P J; Temko, A; Boylan, G; Murphy, E; Cryan, J F; Dinan, T G; Clarke, G

2016-11-01

The emerging concept of psychobiotics-live microorganisms with a potential mental health benefit-represents a novel approach for the management of stress-related conditions. The majority of studies have focused on animal models. Recent preclinical studies have identified the B. longum 1714 strain as a putative psychobiotic with an impact on stress-related behaviors, physiology and cognitive performance. Whether such preclinical effects could be translated to healthy human volunteers remains unknown. We tested whether psychobiotic consumption could affect the stress response, cognition and brain activity patterns. In a within-participants design, healthy volunteers (N=22) completed cognitive assessments, resting electroencephalography and were exposed to a socially evaluated cold pressor test at baseline, post-placebo and post-psychobiotic. Increases in cortisol output and subjective anxiety in response to the socially evaluated cold pressor test were attenuated. Furthermore, daily reported stress was reduced by psychobiotic consumption. We also observed subtle improvements in hippocampus-dependent visuospatial memory performance, as well as enhanced frontal midline electroencephalographic mobility following psychobiotic consumption. These subtle but clear benefits are in line with the predicted impact from preclinical screening platforms. Our results indicate that consumption of B. longum 1714 is associated with reduced stress and improved memory. Further studies are warranted to evaluate the benefits of this putative psychobiotic in relevant stress-related conditions and to unravel the mechanisms underlying such effects.

Activation of the cold-receptor TRPM8 by low levels of menthol in tobacco products.

PubMed

Paschke, Meike; Tkachenko, Anna; Ackermann, Katja; Hutzler, Christoph; Henkler, Frank; Luch, Andreas

2017-04-05

Activation of the cold-receptor TRPM8 by menthol or other tobacco additives can suppress natural defense reactions such as coughing that usually would become effective as involuntary resistance against the inhalation of fumes. In Europe menthol is only regulated as flavor, but can be used as additive as long as no characteristic mint-like aroma will become noticeable in the end-product tobacco. The question needs to be addressed of whether such comparatively minor contents would be sufficient to trigger a measurable activation of TRPM8. In this study, we have analyzed both the contents of menthol and other natural TRPM8 agonists in tobacco products and developed a bioassay to determine the minimum concentrations of selected agonists to activate the TRPM8 receptor in cultured cells. The data confirm menthol as strongest natural agonist investigated. Based on these experiments and previously published data, we have estimated both the minimum menthol concentrations in cigarette smoke and in tobacco that are expected to trigger measurable physiological effects. According to our assessments, TRPM8 activation is likely to occur when cigarettes contain more than 50 micrograms of menthol. Importantly, menthol contents in cigarettes far below the typical levels that require declaration as "mentholated" would be sufficient to activate sensory receptors. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

Effect of cold and hot ambient temperatures on plasma progesterone concentrations in ewes with intact and denervated ovaries containing experimentally maintained corpora lutea.

PubMed

Wheeler, A G; Blackshaw, A W

1986-11-01

Twenty ewes in which maintained corpora lutea had been established were subject to 1 of 3 treatments: denervation of the ovaries by freezing, denervation of the ovaries using the chemical 6-hydroxydopamine, or control. The animals were exposed sequentially to normal (24.5 degrees C), cold (10.7 degrees C), normal (23.8 degrees C), hot (39.4 degrees C) and normal (24.6 degrees C) temperatures, each for 1 week. On the final 3 days of exposure rectal temperatures and heart rates were measured, and on the final day the body weights, respiratory rates, and blood glucose concentrations were measured and a series of 5 blood samples was collected from each ewe for determination of the progesterone concentrations. The progesterone concentration was greatest during the hot period in 8 of the 12 animals, particularly in the ewes with denervated ovaries (6 of the 7 animals). This suggests that high ambient temperatures increase progesterone concentrations non-specifically, and that denervated ovaries are more sensitive to the circulating catecholamines that presumably mediate this effect. The progesterone concentrations were lower (P less than 0.001) in the groups with freezing or chemically denervated ovaries (2.86 and 2.73 ng/ml respectively) than in the control group (3.38 ng/ml), suggesting that the ovarian innervation plays a physiological role in regulating progesterone secretion.

Parasympathetic Activity and Blood Catecholamine Responses Following a Single Partial-Body Cryostimulation and a Whole-Body Cryostimulation

PubMed Central

Hausswirth, Christophe; Schaal, Karine; Le Meur, Yann; Bieuzen, François; Filliard, Jean-Robert; Volondat, Marielle; Louis, Julien

2013-01-01

The aim of this study was to compare the effects of a single whole-body cryostimulation (WBC) and a partial-body cryostimulation (PBC) (i.e., not exposing the head to cold) on indices of parasympathetic activity and blood catecholamines. Two groups of 15 participants were assigned either to a 3-min WBC or PBC session, while 10 participants constituted a control group (CON) not receiving any cryostimulation. Changes in thermal, physiological and subjective variables were recorded before and during the 20-min after each cryostimulation. According to a qualitative statistical analysis, an almost certain decrease in skin temperature was reported for all body regions immediately after the WBC (mean decrease±90% CL, -13.7±0.7°C) and PBC (-8.3±0.3°C), which persisted up to 20-min after the session. The tympanic temperature almost certainly decreased only after the WBC session (-0.32±0.04°C). Systolic and diastolic blood pressures were very likely increased after the WBC session, whereas these changes were trivial in the other groups. In addition, heart rate almost certainly decreased after PBC (-10.9%) and WBC (-15.2%) sessions, in a likely greater proportion for WBC compared to PBC. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) were very likely increased after PBC (RMSSD: +54.4%, HF: +138%) and WBC (RMSSD: +85.2%, HF: +632%) sessions without any marked difference between groups. Plasma norepinephrine concentrations were likely to very likely increased after PBC (+57.4%) and WBC (+76.2%), respectively. Finally, cold and comfort sensations were almost certainly altered after WBC and PBC, sensation of discomfort being likely more pronounced after WBC than PBC. Both acute cryostimulation techniques effectively stimulated the autonomic nervous system (ANS), with a predominance of parasympathetic tone activation. The results of this study also suggest that a whole-body cold exposure induced a larger stimulation of the ANS compared to partial-body cold exposure. PMID:23991134

Pre-harvest nitrogen and azoxystrobin application enhances raw product quality and post-harvest shelf-life of baby spinach (Spinacia oleracea L.).

PubMed

Conversa, Giulia; Bonasia, Anna; Lazzizera, Corrado; Elia, Antonio

2014-12-01

Baby spinach was cultivated under spring or winter conditions to investigate the effect of azoxystrobin and, only in the winter cycle, of nitrogen fertilisation (0, 80 and 120 kg ha(-1) of N) on yield and product morphological traits at harvest and on the physical, visual, bio-physiological, nutritional and anti-nutritional characteristics change during cold storage. The yield was 37% higher in spring than in the overwinter cycle. Spring grown plant had leaves of lighter colour, lower in dry matter content, higher in ascorbic acid, nitrate, and total phenol content. They had higher weight loss during storage than the winter product. Fresh weight was favoured by azoxystrobin only in the non-fertilised plants. During storage azoxystrobin reduced leaf dehydration, contrasted weight loss and the increase in phenols in leaves from fertilised plants. N supply positively affected yield, and greenness of raw and stored leaves. N fertilisation lowered weight loss due to respiration and showed a protective effect on membrane integrity during storage. Azoxystrobin proved effective in reducing nitrate leaf content. Azoxystrobin, especially in fertilised crop, is useful in improving the physiological quality, the safety, and the nutritional quality of baby spinach. A rate of 80 kg ha(-1) can be suggested as optimum N fertilisation. © 2014 Society of Chemical Industry.

Comparison of the Analgesic Effects of Dronabinol and Smoked Marijuana in Daily Marijuana Smokers

PubMed Central

Cooper, Ziva D; Comer, Sandra D; Haney, Margaret

2013-01-01

Recent studies have demonstrated the therapeutic potential of cannabinoids to treat pain, yet none have compared the analgesic effectiveness of smoked marijuana to orally administered Δ9-tetrahydrocannabinol (THC; dronabinol). This randomized, placebo-controlled, double-dummy, double-blind study compared the magnitude and duration of analgesic effects of smoked marijuana and dronabinol under well-controlled conditions using a validated experimental model of pain. Healthy male (N=15) and female (N=15) daily marijuana smokers participated in this outpatient study comparing the analgesic, subjective, and physiological effects of marijuana (0.00, 1.98, or 3.56% THC) to dronabinol (0, 10, or 20 mg). Pain response was assessed using the cold-pressor test (CPT): participants immersed their left hand in cold water (4 °C), and the time to report pain (pain sensitivity) and withdraw the hand from the water (pain tolerance) were recorded. Subjective pain and drug effect ratings were also measured as well as cardiovascular effects. Compared with placebo, marijuana and dronabinol decreased pain sensitivity (3.56% 20 mg), increased pain tolerance (1.98% 20 mg), and decreased subjective ratings of pain intensity (1.98, 3.56% 20 mg). The magnitude of peak change in pain sensitivity and tolerance did not differ between marijuana and dronabinol, although dronabinol produced analgesia that was of a longer duration. Marijuana (1.98, 3.56%) and dronabinol (20 mg) also increased abuse-related subjective ratings relative to placebo; these ratings were greater with marijuana. These data indicate that under controlled conditions, marijuana and dronabinol decreased pain, with dronabinol producing longer-lasting decreases in pain sensitivity and lower ratings of abuse-related subjective effects than marijuana. PMID:23609132

Comparison of the analgesic effects of dronabinol and smoked marijuana in daily marijuana smokers.

PubMed

Cooper, Ziva D; Comer, Sandra D; Haney, Margaret

2013-09-01

Recent studies have demonstrated the therapeutic potential of cannabinoids to treat pain, yet none have compared the analgesic effectiveness of smoked marijuana to orally administered Δ(9)-tetrahydrocannabinol (THC; dronabinol). This randomized, placebo-controlled, double-dummy, double-blind study compared the magnitude and duration of analgesic effects of smoked marijuana and dronabinol under well-controlled conditions using a validated experimental model of pain. Healthy male (N=15) and female (N=15) daily marijuana smokers participated in this outpatient study comparing the analgesic, subjective, and physiological effects of marijuana (0.00, 1.98, or 3.56% THC) to dronabinol (0, 10, or 20 mg). Pain response was assessed using the cold-pressor test (CPT): participants immersed their left hand in cold water (4 °C), and the time to report pain (pain sensitivity) and withdraw the hand from the water (pain tolerance) were recorded. Subjective pain and drug effect ratings were also measured as well as cardiovascular effects. Compared with placebo, marijuana and dronabinol decreased pain sensitivity (3.56%; 20 mg), increased pain tolerance (1.98%; 20 mg), and decreased subjective ratings of pain intensity (1.98, 3.56%; 20 mg). The magnitude of peak change in pain sensitivity and tolerance did not differ between marijuana and dronabinol, although dronabinol produced analgesia that was of a longer duration. Marijuana (1.98, 3.56%) and dronabinol (20 mg) also increased abuse-related subjective ratings relative to placebo; these ratings were greater with marijuana. These data indicate that under controlled conditions, marijuana and dronabinol decreased pain, with dronabinol producing longer-lasting decreases in pain sensitivity and lower ratings of abuse-related subjective effects than marijuana.

Transcriptome profiling of low temperature-treated cassava apical shoots showed dynamic responses of tropical plant to cold stress

PubMed Central

2012-01-01

Background Cassava is an important tropical root crop adapted to a wide range of environmental stimuli such as drought and acid soils. Nevertheless, it is an extremely cold-sensitive tropical species. Thus far, there is limited information about gene regulation and signalling pathways related to the cold stress response in cassava. The development of microarray technology has accelerated the study of global transcription profiling under certain conditions. Results A 60-mer oligonucleotide microarray representing 20,840 genes was used to perform transcriptome profiling in apical shoots of cassava subjected to cold at 7°C for 0, 4 and 9 h. A total of 508 transcripts were identified as early cold-responsive genes in which 319 sequences had functional descriptions when aligned with Arabidopsis proteins. Gene ontology annotation analysis identified many cold-relevant categories, including 'Response to abiotic and biotic stimulus', 'Response to stress', 'Transcription factor activity', and 'Chloroplast'. Various stress-associated genes with a wide range of biological functions were found, such as signal transduction components (e.g., MAP kinase 4), transcription factors (TFs, e.g., RAP2.11), and reactive oxygen species (ROS) scavenging enzymes (e.g., catalase 2), as well as photosynthesis-related genes (e.g., PsaL). Seventeen major TF families including many well-studied members (e.g., AP2-EREBP) were also involved in the early response to cold stress. Meanwhile, KEGG pathway analysis uncovered many important pathways, such as 'Plant hormone signal transduction' and 'Starch and sucrose metabolism'. Furthermore, the expression changes of 32 genes under cold and other abiotic stress conditions were validated by real-time RT-PCR. Importantly, most of the tested stress-responsive genes were primarily expressed in mature leaves, stem cambia, and fibrous roots rather than apical buds and young leaves. As a response to cold stress in cassava, an increase in transcripts and enzyme activities of ROS scavenging genes and the accumulation of total soluble sugars (including sucrose and glucose) were also detected. Conclusions The dynamic expression changes reflect the integrative controlling and transcriptome regulation of the networks in the cold stress response of cassava. The biological processes involved in the signal perception and physiological response might shed light on the molecular mechanisms related to cold tolerance in tropical plants and provide useful candidate genes for genetic improvement. PMID:22321773

Temperature and Nutrients Interact to Control Nitrogen Fixation in a Subalpine Stream: An Experimental Examination

NASA Astrophysics Data System (ADS)

Marcarelli, A. M.

2005-05-01

To test the importance of factors controlling N-fixation in subalpine streams, I conducted a stream-side mesocosm experiment with epilithic communities and nutrient diffusing substrates (NDS) to test how temperature and nutrients interact to influence algal communities. Within two days, warm temperature (18°C) stimulated N-fixation by Calothrix in the epilithic community 2X above cold temperature (13°C), indicating a strong physiological response. Community responses measured on NDS indicated that cold-water diatoms dominated by day 45 in the cold treatment, while diatoms containing N-fixing endosymbionts dominated only in warm treatments with added phosphorus. There was a significant interaction between nutrient supply and temperature on N-fixation rates in the experiment. On nutrient controls, warm temperature boosted fixation 2X above cold temperature, but when P was added, temperature increased fixation 20X. This study indicates that N-fixation is stimulated both by temperature and nutrients in this stream, but the magnitude of response to phosphorus was much greater than to temperature. Furthermore, our results support the hypothesis that biological characteristics in streams, including community structure and biogeochemical processes, can be altered in complex ways by disturbances like grazing and logging that alter multiple controlling factors simultaneously.

Towards a Model of Cold Denaturation of Proteins

NASA Astrophysics Data System (ADS)

Sanchez, Isaac

2010-10-01

Proteins/enzymes can undergo cold denaturation or cold deactivation. In the active or natured state, a protein exists in a unique folded/ordered state. In the deactivated (denatured) state, a protein unfolds and exists in a disordered expanded state. This protein folding/unfolding or order/disorder transition can be triggered by a temperature change. What seems paradoxical is that the active (ordered) state can be induced by heating, or equivalently, the disordered inactive state can be induced by cooling. This is equivalent to an Ising spin model passing from a disordered array of spins to an ordered array by increasing temperature! Hydrogels and their corresponding polyelectrolyte chains behave similarly, i.e., the swollen disordered state can be induced by cooling while the more ordered collapsed or globular state is induced by heating (an entropically driven phase transition). In a living cell at the physiological temperature of 37 C, activation and deactivation of proteins is triggered by local environmental changes in pH, salinity, etc. The important physics is that the denaturation temperature can be moved up or down relative to 37 C by these stimuli. Moving the transition temperature up can destabilize the active protein while moving it down leads to stabilization. An analytical polymer model will be described that exhibits cold denaturation behavior.

Experimental study on the monomer structure of solar semiconductor cold wall

NASA Astrophysics Data System (ADS)

Fu, Yuanyuan; Liu, Qiuxin; Chen, Tianshou

2018-06-01

In this paper, solar semiconductor cold wall structure was adopted in the net-zero energy buildings, NZEB for short. The heat transfer and refrigeration effect of the monomer structure of semiconductor cold wall were tested, we get that the monomer structure of semiconductor cold wall has certain cooling effect. However, the heat exchange effect is not good of the cold and hot aluminum plate only through natural convection and radiation heat transfer. It is necessary to further study the process of semiconductor refrigeration and heat transfer and the factors that affect the cooling effect. At the same time, it put forward a series of suggestions and improvement opinion for NZEB in hot summer and cold winter areas.

Hsp60 expression profiles in the reef-building coral Seriatopora caliendrum subjected to heat and cold shock regimes.

PubMed

Seveso, Davide; Montano, Simone; Strona, Giovanni; Orlandi, Ivan; Galli, Paolo; Vai, Marina

2016-08-01

Climate changes have increased the intensity/frequency of extreme thermal events, which represent serious threats to the health of reef-building corals. Since the vulnerability of corals exposed to thermal stresses are related to their ability to regulate Heat shock proteins (Hsps), we have analyzed together the time related expression profiles of the mitochondrial Hsp60 and the associated changes in tissue pigmentation in Seriatopora caliendrum subjected to 48 h of heat and cold treatments characterized by moderate (±2 °C) and severe (±6 °C) shocks. For the first time, an Hsp60 response was observed in a scleractinian coral exposed to cold stresses. Furthermore, the Hsp60 modulations and the changes in the tissue coloration were found to be specific for each treatment. A strong down-regulation at the end of the treatments was observed following both the severe shocks, but only the severe heat stress led to bleaching in concert with the lowest levels of Hsp60, suggesting that a severe heat shock can be more deleterious than an exposure to a severe cold temperature. On the contrary, a moderate cold stress seems to be more harmful than a moderate temperature increase, which could allow coral acclimation. Our results can provide a potential framework for understanding the physiological tolerance of corals under possible future climate changes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physiological differences between female limited, alternative life history strategies: The Alba phenotype in the butterfly Colias croceus.

PubMed

Woronik, Alyssa; Stefanescu, Constanti; Käkelä, Reijo; Wheat, Christopher W; Lehmann, Philipp

Across a wide range of taxa, individuals within populations exhibit alternative life history strategies (ALHS) where their phenotypes dramatically differ due to divergent investments in growth, reproduction and survivorship, with the resulting trade-offs directly impacting Darwinian fitness. Though the maintenance of ALHS within populations is fairly well understood, little is known regarding the physiological mechanisms that underlie ALHS and how environmental conditions can affect the evolution and expression of these phenotypes. One such ALHS, known as Alba, exists within females of many species in the butterfly genus Colias. Previous works in New World species not only found that female morphs differ in their wing color due to a reallocation of resources away from the synthesis of wing pigments to other areas of development, but also that temperature played an important role in these trade-offs. Here we build on previous work conducted in New World species by measuring life history traits and conducting lipidomics on individuals reared at hot and cold temperatures in the Old World species Colias croceus. Results suggest that the fitness of Alba and orange morphs likely varies with rearing temperature, where Alba females have higher fitness in cold conditions and orange in warm. Additionally shared traits between Old and New World species suggest the Alba mechanism is likely conserved across the genus. Finally, in the cold treatment we observe an intermediate yellow morph that may have decreased fitness due to slower larval development. This cost may manifest as disruptive selection in the field, thereby favoring the maintenance of the two discrete morphs. Taken together these results add insights into the evolution of, and the selection on, the Alba ALHS. Copyright © 2018 Elsevier Ltd. All rights reserved.

Using thermal stress to model aspects of disease states.

PubMed

Wilson, Thad E; Klabunde, Richard E; Monahan, Kevin D

2014-07-01

Exposure to acute heat or cold stress elicits numerous physiological responses aimed at maintaining body temperatures. Interestingly, many of the physiological responses, mediated by the cardiovascular and autonomic nervous systems, resemble aspects of, or responses to, certain disease states. The purpose of this Perspective is to highlight some of these areas in order to explore how they may help us better understand the pathophysiology underlying aspects of certain disease states. The benefits of using this human thermal stress approach are that (1) no adjustments for inherent comparative differences in animals are needed, (2) non-medicated healthy humans with no underlying co-morbidities can be studied in place of complex patients, and (3) more mechanistic perturbations can be safely employed without endangering potentially vulnerable populations. Cold stress can be used to induce stable elevations in blood pressure. Cold stress may also be used to model conditions where increases in myocardial oxygen demand are not met by anticipated increases in coronary blood flow, as occurs in older adults. Lower-body negative pressure has the capacity to model aspects of shock, and the further addition of heat stress improves and expands this model because passive-heat exposure lowers systemic vascular resistance at a time when central blood volume and left-ventricular filling pressure are reduced. Heat stress can model aspects of heat syncope and orthostatic intolerance as heat stress decreases cerebral blood flow and alters the Frank-Starling mechanism resulting in larger decreases in stroke volume for a given change in left-ventricular filling pressure. Combined, thermal perturbations may provide in vivo paradigms that can be employed to gain insights into pathophysiological aspects of certain disease states. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cellular respiration, oxygen consumption, and trade-offs of the jellyfish Cassiopea sp. in response to temperature change

NASA Astrophysics Data System (ADS)

Aljbour, Samir M.; Zimmer, Martin; Kunzmann, Andreas

2017-10-01

Pelagic jellyfish blooms are increasing worldwide as a potential response to climate-change. However, virtually nothing is known about physiological responses of jellyfish to e.g. sudden changes in water temperature due to extreme weather events. When confronted with a sudden decrease or increase in water temperature by 6 °C, medusae of Cassiopea sp. exhibited a strong response in locomotor activity (i.e., bell pulsation increased and decreased by ca. 37 and 46% in hot and cold acute (2 h) treatments, respectively) relative to control. Although medusae significantly gained in body mass (wet weight) upon chronic (2 weeks) heat treatment, their body size (e.g., bell diameter) did not change over this time interval. In contrast, chronic cold treatment resulted in both significant shrinking (reduced diameter) and mass loss. Measurements of mitochondrial electron transport system (ETS) activities and rate of respiratory oxygen uptake (MO2) are good estimates of energy consumption and the potential aerobic metabolic rates of an organism. While both acute treatments significantly increased ETS-activities, acclimation over two weeks resulted in a drop in activities to the control levels. Whereas acute heat treatment significantly increased MO2, chronic exposure resulted in significant MO2 decrease compared to control; however no changes in MO2 could be observed in both acute and chronic cold treatments. Overall these results suggest an enhanced growth in response to global warming, whereas low temperatures may set the limits for successful invasion of Cassiopea into colder water bodies. Our results provide a framework for understanding the physiological tolerance of Cassiopea under possible future climate changes.

Lessons from history: morbidity of cold injury in the Royal Marines during the Falklands Conflict of 1982

PubMed Central

2013-01-01

Background Environmental conditions in the Falklands Conflict of 1982 favoured the genesis of cold injuries. Immediately, post-war, cold injury morbidity and its contributory factors were assessed, in the personnel of UK 3 Commando Brigade (3 Cdo Bde). Methods A questionnaire survey of the 3,006 members of 3 Cdo Bde who landed on the islands was conducted within 6–10 weeks of the end of hostilities. Questions included those relating to features of cold injury, body morphology, age, symptoms experienced, past medical history and other possible contributory causes. Additionally, the unit medical team conducted a cursory examination. Data were sent to the Royal Navy Institute of Naval Medicine (INM), where the degree of likely cold injury was broadly classified (‘asymptomatic’ ‘mild’, ‘moderate’ or ‘severe’). A sample (total 109) was then selected at random from each category and subsequently examined and tested at the INM (nerve conduction, photoplethysmography and thermography testing). Forty-seven non-cold exposed sailors acted as a control group. These contemporaneous records have now been identified and interrogated. Results Some 2,354 (78%) completed questionnaires were returned, revealing that 1,505 (64%) had experienced symptoms of non-freezing cold injury. The morbidity in the infantry units was significantly greater than that in the support troops (1,051 (76%) vs 454 (46%), p < 0.05). No evidence was found to support an influence of a number of factors, commonly believed to have an aetiological role in the production of cold injury. Whilst there was no significant relationship between past history and cold injury morbidity in the brigade as a whole, or within the infantry units alone, an association was identified in the collective infantry units (73%) and the support/headquarter units (59%) (p < 0.05). In comparison with uninjured sailors who acted as controls (n = 47), nerve conduction was impaired in 35% of those screened some months after returning to the UK, while the photoplethysmography and thermographic responses to a cold sensitivity test showed that most (including those classed by questionnaire as asymptomatic) had residual ‘cold sensitivity’. Conclusions Although the passage of time has made retrospective interrogation of historical documents hard, the available data do appear to offer valuable historical and clinical insights. Cold injury affected the majority of those fighting in the cold temperate climate of the Falklands. The overwhelming environmental conditions meant that, for most, a past history of cold injury did not appear to represent a risk factor for subsequent injury, as is the case for less severe conditions. Importantly, even asymptomatic individuals when tested often showed physiological evidence of cold injury—perhaps predisposing them to subsequent elevation in risk. PMID:24070118

Huddling remodels gut microbiota to reduce energy requirements in a small mammal species during cold exposure.

PubMed

Zhang, Xue-Ying; Sukhchuluun, Gansukh; Bo, Ting-Bei; Chi, Qing-Sheng; Yang, Jun-Jie; Chen, Bin; Zhang, Lei; Wang, De-Hua

2018-06-08

Huddling is highly evolved as a cooperative behavioral strategy for social mammals to maximize their fitness in harsh environments. Huddling behavior can change psychological and physiological responses. The coevolution of mammals with their microbial communities confers fitness benefits to both partners. The gut microbiome is a key regulator of host immune and metabolic functions. We hypothesized that huddling behavior altered energetics and thermoregulation by shaping caecal microbiota in small herbivores. Brandt's voles (Lasiopodomys brandtii) were maintained in a group (huddling) or as individuals (separated) and were exposed to warm (23 ± 1 °C) and cold (4 ± 1 °C) air temperatures (T a ). Voles exposed to cold T a had higher energy intake, resting metabolic rate (RMR) and nonshivering thermogenesis (NST) than voles exposed to warm T a . Huddling voles had lower RMR and NST than separated voles in cold. In addition, huddling voles had a higher surface body temperature (T surface ), but lower core body temperature (T core ) than separated voles, suggesting a lower set-point of T core in huddling voles. Both cold and huddling induced a marked variation in caecal bacterial composition, which was associated with the lower T core . Huddling voles had a higher α and β-diversity, abundance of Lachnospiraceae and Veillonellaceae, but lower abundance of Cyanobacteria, Tenericutes, TM7, Comamonadaceae, and Sinobacteraceae than separated voles. Huddling or cold resulted in higher concentrations of short-chain fatty acids (SCFAs), particularly acetic acid and butyric acid when compared to their counterparts. Transplantation of caecal microbiota from cold-separated voles but not from cold-huddling voles induced significant increases in energy intake and RMR compared to that from warm-separated voles. These findings demonstrate that the remodeling of gut microbiota, which is associated with a reduction in host T core , mediates cold- and huddling-induced energy intake and thermoregulation and therefore orchestrates host metabolic and thermal homeostasis. It highlights the coevolutionary mechanism of host huddling and gut microbiota in thermoregulation and energy saving for winter survival in endotherms.

Some Chinese folk prescriptions for wind-cold type common cold.

PubMed

Hai-Long, Zhai; Shimin, Chen; Yalan, Lu

2015-07-01

Although self-limiting, the common cold (gǎn mào) is highly prevalent. There are no effective antivirals to cure the common cold and few effective measures to prevent it, However, for thousands years, Chinese people have treated the common cold with natural herbs, According to the traditional Chinese medicine (TCM) theory ( zhōng yī lǐ lùn), the common cold is considered as an exterior syndrome, which can be further divided into the wind-cold type ( fēng hán xíng), the wind-heat type ( fēng rè xíng), and the summer heat dampness type ( shǔ rè xíng). Since the most common type of common cold caught in winter and spring is the wind-cold type, the article introduced some Chinese folk prescriptions for the wind-cold type common cold with normal and weak physique, respectively. For thousands of years, Chinese folk prescriptions for the common cold, as complementary and alternative medicine (CAM; bǔ chōng yǔ tì dài yī xué), have been proven to be effective, convenient, cheap, and most importantly, safe. The Chinese folk prescriptions ( zhōng guó mín jiān chǔ fāng) for the wind-cold type common cold are quite suitable for general practitioners or patients with the wind-cold type common cold, to treat the disease. Of course, their pharmacological features and mechanisms of action need to be further studied.

Thermodynamics of protein destabilization in live cells.

PubMed

Danielsson, Jens; Mu, Xin; Lang, Lisa; Wang, Huabing; Binolfi, Andres; Theillet, François-Xavier; Bekei, Beata; Logan, Derek T; Selenko, Philipp; Wennerström, Håkan; Oliveberg, Mikael

2015-10-06

Although protein folding and stability have been well explored under simplified conditions in vitro, it is yet unclear how these basic self-organization events are modulated by the crowded interior of live cells. To find out, we use here in-cell NMR to follow at atomic resolution the thermal unfolding of a β-barrel protein inside mammalian and bacterial cells. Challenging the view from in vitro crowding effects, we find that the cells destabilize the protein at 37 °C but with a conspicuous twist: While the melting temperature goes down the cold unfolding moves into the physiological regime, coupled to an augmented heat-capacity change. The effect seems induced by transient, sequence-specific, interactions with the cellular components, acting preferentially on the unfolded ensemble. This points to a model where the in vivo influence on protein behavior is case specific, determined by the individual protein's interplay with the functionally optimized "interaction landscape" of the cellular interior.

Heterothermy in growing king penguins.

PubMed

Eichhorn, Götz; Groscolas, René; Le Glaunec, Gaële; Parisel, Camille; Arnold, Laurent; Medina, Patrice; Handrich, Yves

2011-08-16

A drop in body temperature allows significant energy savings in endotherms, but facultative heterothermy is usually restricted to small animals. Here we report that king penguin chicks (Aptenodytes patagonicus), which are able to fast for up to 5 months in winter, undergo marked seasonal heterothermy during this period of general food scarcity and slow-down of growth. They also experience short-term heterothermy below 20 °C in the lower abdomen during the intense (re)feeding period in spring, induced by cold meals and adverse weather. The heterothermic response involves reductions in peripheral temperature, reductions in thermal core volume and temporal abandonment of high core temperature. Among climate variables, air temperature and wind speed show the strongest effect on body temperature, but their effect size depends on physiological state. The observed heterothermy is remarkable for such a large bird (10 kg before fasting), which may account for its unrivalled fasting capacity among birds.

Acid adaptation of Lactobacillus delbrueckii subsp. bulgaricus induces physiological responses at membrane and cytosolic levels that improves cryotolerance.

PubMed

Streit, F; Delettre, J; Corrieu, G; Béal, C

2008-10-01

This work aimed at clarifying the physiological responses of Lactobacillus delbrueckii subsp. bulgaricus CFL1 cells after exposure to acidification at the end of fermentation, in relation to their cryotolerance. Cells acidified at the end of the fermentation (pH 5.25 for 30 min) had their cryotolerance improved as compared to the reference condition (pH 6.0). By analyzing the cytosolic proteome, it was established that changes occurred in the synthesis of 21 proteins, involved in energy metabolism, nucleotide and protein synthesis and stress response. Acidification also induced a slight decrease in unsaturated to saturated and cyclic to saturated membrane fatty acid ratios. Lactobacillus bulgaricus CFL1 was able to develop a combined physiological response at both membrane and cytosolic levels. This acid adaptation was referred as a cross-protection phenomenon as it allowed the cells to become more tolerant to cold stress. This study increased knowledge concerning the physiological mechanisms that explained the cross-protection by acid adaptation. It may be useful for improving cryotolerance of lactic acid bacteria, either in cells banks or in an industrial context.

Controlled atmosphere pO2 alters ripening dynamics of 1-MCP treated ‘d’Anjou’ pear (Pyrus communis L.) fruit

USDA-ARS?s Scientific Manuscript database

Ripening and development of physiological disorders and decay were assessed in ‘d’Anjou’ pear fruit following 1-methylcyclopropene (1-MCP) treatment and cold storage in air or controlled atmosphere (CA). Fruit were exposed after harvest to 0 or 12.6 µmol•L-1 1-MCP and then stored at 0.5 oC in air o...

Brown Adipose Tissue Is Linked to a Distinct Thermoregulatory Response to Mild Cold in People

PubMed Central

Chondronikola, Maria; Volpi, Elena; Børsheim, Elisabet; Chao, Tony; Porter, Craig; Annamalai, Palam; Yfanti, Christina; Labbe, Sebastien M.; Hurren, Nicholas M.; Malagaris, Ioannis; Cesani, Fernardo; Sidossis, Labros S.

2016-01-01

Brown adipose tissue (BAT) plays an important role in thermoregulation in rodents. Its role in temperature homeostasis in people is less studied. To this end, we recruited 18 men [8 subjects with no/minimal BAT activity (BAT−) and 10 with pronounced BAT activity (BAT+)]. Each volunteer participated in a 6 h, individualized, non-shivering cold exposure protocol. BAT was quantified using positron emission tomography/computed tomography. Body core and skin temperatures were measured using a telemetric pill and wireless thermistors, respectively. Core body temperature decreased during cold exposure in the BAT− group only (−0.34°C, 95% CI: −0.6 to −0.1, p = 0.03), while the cold-induced change in core temperature was significantly different between BAT+ and BAT− subjects (BAT+ vs. BAT−, 0.43°C, 95% CI: 0.20–0.65, p = 0.0014). BAT volume was associated with the cold-induced change in core temperature (p = 0.01) even after adjustment for age and adiposity. Compared to the BAT− group, BAT+ subjects tolerated a lower ambient temperature (BAT−: 20.6 ± 0.3°C vs. BAT+: 19.8 ± 0.3°C, p = 0.035) without shivering. The cold-induced change in core temperature (r = 0.79, p = 0.001) and supraclavicular temperature (r = 0.58, p = 0.014) correlated with BAT volume, suggesting that these non-invasive measures can be potentially used as surrogate markers of BAT when other methods to detect BAT are not available or their use is not warranted. These results demonstrate a physiologically significant role for BAT in thermoregulation in people. This trial has been registered with Clinaltrials.gov: NCT01791114 (https://clinicaltrials.gov/ct2/show/NCT01791114). PMID:27148068

PpCBF3 from Cold-Tolerant Kentucky Bluegrass Involved in Freezing Tolerance Associated with Up-Regulation of Cold-Related Genes in Transgenic Arabidopsis thaliana

PubMed Central

Chen, Yu; Xu, Bin; Yang, Zhimin; Huang, Bingru

2015-01-01

Dehydration-Responsive Element Binding proteins (DREB)/C-repeat (CRT) Binding Factors (CBF) have been identified as transcriptional activators during plant responses to cold stress. The objective of this study was to determine the physiological roles of a CBF gene isolated from a cold-tolerant perennial grass species, Kentucky bluegrass (Poa pratensis L.), which designated as PpCBF3, in regulating plant tolerance to freezing stress. Transient transformation of Arabidopsis thaliana mesophyll protoplast with PpCBF3-eGFP fused protein showed that PpCBF3 was localized to the nucleus. RT-PCR analysis showed that PpCBF3 was specifically induced by cold stress (4°C) but not by drought stress [induced by 20% polyethylene glycol 6000 solution (PEG-6000)] or salt stress (150 mM NaCl). Transgenic Arabidopsis overexpressing PpCBF3 showed significant improvement in freezing (-20°C) tolerance demonstrated by a lower percentage of chlorotic leaves, lower cellular electrolyte leakage (EL) and H2O2 and O2 .- content, and higher chlorophyll content and photochemical efficiency compared to the wild type. Relative mRNA expression level analysis by qRT-PCR indicated that the improved freezing tolerance of transgenic Arabidopsis plants overexpressing PpCBF3 was conferred by sustained activation of downstream cold responsive (COR) genes. Other interesting phenotypic changes in the PpCBF3-transgenic Arabidopsis plants included late flowering and slow growth or ‘dwarfism’, both of which are desirable phenotypic traits for perennial turfgrasses. Therefore, PpCBF3 has potential to be used in genetic engineering for improvement of turfgrass freezing tolerance and other desirable traits. PMID:26177510

Validity of field expedient devices to assess core temperature during exercise in the cold.

PubMed

Bagley, James R; Judelson, Daniel A; Spiering, Barry A; Beam, William C; Bartolini, J Albert; Washburn, Brian V; Carney, Keven R; Muñoz, Colleen X; Yeargin, Susan W; Casa, Douglas J

2011-12-01

Exposure to cold environments affects human performance and physiological function. Major medical organizations recommend rectal temperature (TREC) to evaluate core body temperature (TcORE) during exercise in the cold; however, other field expedient devices claim to measure TCORE. The purpose of this study was to determine if field expedient devices provide valid measures of TcRE during rest and exercise in the cold. Participants included 13 men and 12 women (age = 24 +/- 3 yr, height = 170.7 +/- 10.6 cm, mass = 73.4 +/- 16.7 kg, body fat = 18 +/- 7%) who reported being healthy and at least recreationally active. During 150 min of cold exposure, subjects sequentially rested for 30 min, cycled for 90 min (heart rate = 120-140 bpm), and rested for an additional 30 min. Investigators compared aural (T(AUR)), expensive axillary (T(AXLe)), inexpensive axillary (T(AXLi)), forehead (T(FOR)), gastrointestinal (T(GI)), expensive oral (T(ORLe)), inexpensive oral (T(ORLi)), and temporal (T(TEM)) temperatures to T(REc) every 15 min. Researchers used mean difference between each device and T(REC) (i.e., mean bias) as the primary criterion for validity. T(AUR), T(AXLe), T(AXLi), T(FOR), TORLe, T(ORLi), and TTEM provided significantly lower measures compared to T(REC) and fell below our validity criterion. T(GI) significantly exceeded T(REC) at three of eleven time points, but no significant difference existed between mean T(REC) and T(GI) across time. Only T(GI) achieved our validity criterion and compared favorably to T(REC). T(GI) offers a valid measurement with which to assess T(CORE) during rest and exercise in the cold; athletic trainers, mountain rescuers, and military medical personnel should avoid other field expedient devices in similar conditions.

Improved biochemical preservation of heart slices during cold storage.

PubMed

Bull, D A; Reid, B B; Connors, R C; Albanil, A; Stringham, J C; Karwande, S V

2000-01-01

Development of myocardial preservation solutions requires the use of whole organ models which are animal and labor intensive. These models rely on physiologic rather than biochemical endpoints, making accurate comparison of the relative efficacy of individual solution components difficult. We hypothesized that myocardial slices could be used to assess preservation of biochemical function during cold storage. Whole rat hearts were precision cut into slices with a thickness of 200 microm and preserved at 4 degrees C in one of the following solutions: Columbia University (CU), University of Wisconsin (UW), D5 0.2% normal saline with 20 meq/l KCL (QNS), normal saline (NS), or a novel cardiac preservation solution (NPS) developed using this model. Myocardial biochemical function was assessed by ATP content (etamoles ATP/mg wet weight) and capacity for protein synthesis (counts per minute (cpm)/mg protein) immediately following slicing (0 hours), and at 6, 12, 18, and 24 hours of cold storage. Six slices were assayed at each time point for each solution. The data were analyzed using analysis of variance and are presented as the mean +/- standard deviation. ATP content was higher in the heart slices stored in the NPS compared to all other solutions at 6, 12, 18 and 24 hours of cold storage (p < 0.05). Capacity for protein synthesis was higher in the heart slices stored in the NPS compared to all other solutions at 6, 12, and 18 hours of cold storage (p < 0.05). CONCLUSIONS This myocardial slice model allows the rapid and efficient screening of cardiac preservation solutions and their components using quantifiable biochemical endpoints. Using this model, we have developed a novel preservation solution which improves the biochemical function of myocardial slices during cold storage.

Does water temperature influence the performance of key survival skills?

PubMed

Schnitzler, C; Button, C; Seifert, L; Armbrust, G; Croft, J L

2018-03-01

Aquatic survival skills may be compromised in cold water thereby increasing the likelihood of drowning. This study compared physiological, psychological, and behavioral responses of humans treading water and swimming in cold and temperate water. Thirty-eight participants were classified as inexperienced (n = 9), recreational (n = 15), or skilled (n = 10) swimmers. They performed 3 tasks: treading water (120 seconds), swim at "comfortable" pace, and swim at "fast" pace in 2 water conditions (28°C vs 10°C). Heart rate, oxygen uptake, psychometric variables, spatio-temporal (swim speed, stroke rate, and stroke length), and coordination type were examined as a function of expertise. Tasks performed in cold water-generated higher cardiorespiratory responses (HR = 145 ± 16 vs 127 ± 21 bpm) and were perceived about 2 points more strenuous on the Borg scale on average (RPE = 14.9 ± 2.8 vs 13.0 ± 2.0). The voluntary durations of both treading water (60 ± 32 vs 91 ± 33 seconds) and swimming at a comfortable pace (66 ± 22 vs 103 ± 34 seconds) were significantly reduced in cold water. However, no systematic changes in movement pattern type could be determined in either the treading water task or the swimming tasks. Water temperature influences the physical demands of these aquatic skills but not necessarily the behavior. Training treading water and swimming skills in temperate water seems to transfer to cold water, but we recommend training these skills in a range of water conditions to help adapt to the initial "cold-shock" response. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Metabolomic and physico-chemical approach unravel dynamic regulation of calcium in sweet cherry fruit physiology.

PubMed

Michailidis, Michail; Karagiannis, Evangelos; Tanou, Georgia; Karamanoli, Katerina; Lazaridou, Athina; Matsi, Theodora; Molassiotis, Athanassios

2017-07-01

Calcium (Ca 2 ) nutrition has a significant role in fruit physiology; however, the underlying mechanism is still unclear. In this study, fruit quality in response to CaCl 2 , applied via foliar sprays (Ca 2 ) or/and hydro-cooling water (Ca HC ), was characterized in 'Lapins' cherries at harvest, just after cold storage (20 days at 0 °C) as well as after cold storage followed by 2 days at 20 °C, herein defined as shelf-life period. Data indicated that pre- and post-harvest Ca 2+ applications increased total Ca 2+ and cell wall bound Ca 2+ , respectively. Treatment with Ca reduced cracking whereas Ca + Ca HC condition depressed stem browning. Both skin penetration and stem removal were affected by Ca 2+ feeding. Also, several color- and antioxidant-related parameters were induced by Ca 2+ treatments. Metabolomic analysis revealed significant alterations in primary metabolites among the Ca 2+ treatments, including sugars (eg., glucose, fructose), soluble alcohols (eg., arabitol, sorbitol), organic acids (eg.,malate, quinate) and amino acids (eg., glycine, beta-alanine). This work helps to improve our knowledge on the fruit's response to Ca 2+ nutrition. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Ten years of research with the Socially Evaluated Cold Pressor Test: Data from the past and guidelines for the future.

PubMed

Schwabe, Lars; Schächinger, Hartmut

2018-06-01

Ten years ago, the Socially Evaluated Cold Pressor Test (SECPT) was introduced as a standardized protocol for the efficient experimental stress induction in humans. In short, the 3 min SECPT, which can be conducted by only a single experimenter, combines a physiological challenge (hand immersion into ice water) with socio-evaluative elements. The purpose of this article is twofold. First, we aim to evaluate the subjective and physiological responses elicited by the SECPT. To this end, we pooled data from 21 studies from our lab and systematically analyzed the response profile to the SECPT. Our analyses show that the SECPT leads, both in men and women, to striking increases in subjective stress levels, autonomic arousal, and cortisol, albeit the cortisol response is typically somewhat less pronounced than in the Trier Social Stress Test. Second, we aim to provide guidelines for conducting the SECPT, in order to foster homogenization of the SECPT procedure across (and within) labs. In sum, we argue that the SECPT is a highly efficient tool to induce stress and activate major stress systems in a laboratory context, in particular if the guidelines that we outline here are followed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Potential for increased photosynthetic performance and crop productivity in response to climate change: role of CBFs and gibberellic acid

PubMed Central

Hüner, Norman P. A.; Dahal, Keshav; Kurepin, Leonid V.; Savitch, Leonid; Singh, Jas; Ivanov, Alexander G.; Kane, Khalil; Sarhan, Fathey

2014-01-01

We propose that targeting the enhanced photosynthetic performance associated with the cold acclimation of winter cultivars of rye (Secale cereale L.), wheat (Triticum aestivum L.), and Brassica napus L. may provide a novel approach to improve crop productivity under abiotic as well as biotic stress conditions. In support of this hypothesis, we provide the physiological, biochemical, and molecular evidence that the dwarf phenotype induced by cold acclimation is coupled to significant enhancement in photosynthetic performance, resistance to photoinhibition, and a decreased dependence on photoprotection through non-photochemical quenching which result in enhanced biomass production and ultimately increased seed yield. These system-wide changes at the levels of phenotype, physiology, and biochemistry appear to be governed by the family of C-repeat/dehydration-responsive family of transcription factors (CBF/DREB1). We relate this phenomenon to the semi-dwarf, gibberellic acid insensitive (GAI), cereal varieties developed during the “green revolution” of the early 1960s and 1970s. We suggest that genetic manipulation of the family of C-repeat/dehydration-responsive element binding transcription factors (CBF/DREB1) may provide a novel approach for the maintenance and perhaps even the enhancement of plant productivity under conditions of sub-optimal growth conditions predicted for our future climate. PMID:24860799

Distinct vasopressin content in the hypothalamic supraoptic and paraventricular nucleus of rats exposed to low and high ambient temperature.

PubMed

Jasnic, N; Dakic, T; Bataveljic, D; Vujovic, P; Lakic, I; Jevdjovic, T; Djurasevic, S; Djordjevic, J

2015-08-01

Both high and low ambient temperature represent thermal stressors that, among other physiological responses, induce activation of the hypothalamic-pituitary-adrenal (HPA) axis and secretion of arginine-vasopressin (AVP). The exposure to heat also leads to disturbance of osmotic homeostasis. Since AVP, in addition to its well-known peripheral effects, has long been recognized as a hormone involved in the modulation of HPA axis activity, the aim of the present study was to elucidate the hypothalamic AVP amount in the acutely heat/cold exposed rats. Rats were exposed to high (+38°C) or low (+4°C) ambient temperature for 60min. Western blot was employed for determining hypothalamic AVP levels, and the difference in its content between supraoptic (SON) and paraventricular nucleus (PVN) was detected using immunohistochemical analysis. The results showed that exposure to both high and low ambient temperature increased hypothalamic AVP levels, although the increment was higher under heat conditions. On the other hand, patterns of AVP level changes in PVN and SON were stressor-specific, given that exposure to cold increased the AVP level in both nuclei, while heat exposure affected the PVN AVP content alone. In conclusion, our results revealed that cold and heat stress influence hypothalamic AVP amount with different intensity. Moreover, different pattern of AVP amount changes in the PVN and SON indicates a role of this hormone not only in response to heat as an osmotic/physical threat, but to the non-osmotic stressors as well. Copyright © 2015 Elsevier Ltd. All rights reserved.

TRPM8 and prostate: a cold case?

PubMed

Noyer, Lucile; Grolez, Guillaume P; Prevarskaya, Natalia; Gkika, Dimitra; Lemonnier, Loic

2018-06-20

While originally cloned from the prostate in 2001, transient receptor potential, melastatin member 8 (TRPM8) has since been identified as the cold/menthol receptor in the peripheral nervous system. This discovery has led to hundreds of studies regarding the role of this channel in pain and thermosensation phenomena, while relegating TRPM8 involvement in cancer to a secondary role. Despite these findings, there is growing evidence that TRPM8 should be carefully studied within the frame of carcinogenesis, especially in the prostate, where it is highly expressed and where many teams have confirmed variations in its expression during cancer progression. Its regulation by physiological factors, such as PSA and androgens, has proved that TRPM8 can exhibit an activity beyond that of a cold receptor, thus explaining how the channel can be activated in organs not exposed to temperature variations. With this review, we aim to provide a brief overview of the current knowledge regarding the complex roles of TRPM8 in prostate carcinogenesis and to show that this research path still represents a "hot" topic with potential clinical applications in the short term.

Chilling Stress Upregulates α-Linolenic Acid-Oxidation Pathway and Induces Volatiles of C6 and C9 Aldehydes in Mango Fruit.

PubMed

Sivankalyani, Velu; Maoz, Itay; Feygenberg, Oleg; Maurer, Dalia; Alkan, Noam

2017-01-25

Mango-fruit storage period and shelf life are prolonged by cold storage. However, chilling temperature induces physiological and molecular changes, compromising fruit quality. In our previous transcriptomic study of mango fruit, cold storage at suboptimal temperature (5 °C) activated the α-linolenic acid metabolic pathway. To evaluate changes in fruit quality during chilling, we analyzed mango "Keitt" fruit peel volatiles. GC-MS analysis revealed significant modulations in fruit volatiles during storage at suboptimal temperature. Fewer changes were seen in response to the time of storage. The mango volatiles related to aroma, such as δ-3-carene, (Z)-β-ocimene, and terpinolene, were downregulated during the storage at suboptimal temperature. In contrast, C 6 and C 9 aldehydes and alcohols-α-linolenic acid derivatives 1-hexanal, (Z)-3-hexenal, (Z)-3-hexenol, (E)-2-hexenal, and nonanal-were elevated during suboptimal-temperature storage, before chilling-injury symptoms appeared. Detection of those molecules before chilling symptoms could lead to a new agro-technology to avoid chilling injuries and maintain fruit quality during cold storage at the lowest possible temperature.

The impact of temperature on mortality in a subtropical city: effects of cold, heat, and heat waves in São Paulo, Brazil

NASA Astrophysics Data System (ADS)

Son, Ji-Young; Gouveia, Nelson; Bravo, Mercedes A.; de Freitas, Clarice Umbelino; Bell, Michelle L.

2016-01-01

Understanding how weather impacts health is critical, especially under a changing climate; however, relatively few studies have investigated subtropical regions. We examined how mortality in São Paulo, Brazil, is affected by cold, heat, and heat waves over 14.5 years (1996-2010). We used over-dispersed generalized linear modeling to estimate heat- and cold-related mortality, and Bayesian hierarchical modeling to estimate overall effects and modification by heat wave characteristics (intensity, duration, and timing in season). Stratified analyses were performed by cause of death and individual characteristics (sex, age, education, marital status, and place of death). Cold effects on mortality appeared higher than heat effects in this subtropical city with moderate climatic conditions. Heat was associated with respiratory mortality and cold with cardiovascular mortality. Risk of total mortality was 6.1 % (95 % confidence interval 4.7, 7.6 %) higher at the 99th percentile of temperature than the 90th percentile (heat effect) and 8.6 % (6.2, 11.1 %) higher at the 1st compared to the 10th percentile (cold effect). Risks were higher for females and those with no education for heat effect, and males for cold effect. Older persons, widows, and non-hospital deaths had higher mortality risks for heat and cold. Mortality during heat waves was higher than on non-heat wave days for total, cardiovascular, and respiratory mortality. Our findings indicate that mortality in São Paulo is associated with both cold and heat and that some subpopulations are more vulnerable.

Deep simple epicotyl morphophysiological dormancy in seeds of two Viburnum species, with special reference to shoot growth and development inside the seed.

PubMed

Chien, Ching-Te; Chen, Shun-Ying; Tsai, Ching-Chu; Baskin, Jerry M; Baskin, Carol C; Kuo-Huang, Ling-Long

2011-07-01

In seeds with deep simple epicotyl morphophysiological dormancy, warm and cold stratification are required to break dormancy of the radicle and shoot, respectively. Although the shoot remains inside the seed all winter, little is known about its growth and morphological development prior to emergence in spring. The aims of the present study were to determine the temperature requirements for radicle and shoot emergence in seeds of Viburnum betulifolium and V. parvifolium and to monitor growth of the epicotyl, plumule and cotyledons in root-emerged seeds. Fresh and pre-treated seeds of V. betulifolium and V. parvifolium were incubated under various temperature regimes and monitored for radicle and shoot emergence. Growth of the epicotyl and cotyledons at different stages was observed with dissecting and scanning electron microscopes. The optimum temperature for radicle emergence of seeds of both species, either kept continuously at a single regime or exposed to a sequence of regimes, was 20/10 °C. GA(3) had no effect on radicle emergence. Cold stratification (5 °C) was required for shoot emergence. The shoot apical meristem in fresh seeds did not form a bulge until the embryo had grown to the critical length for radicle emergence. After radicle emergence, the epicotyl--plumule and cotyledons grew slowly at 5 and 20/10 °C, and the first pair of true leaves was initiated. However, the shoot emerged only from seeds that received cold stratification. Seeds of V. betulifolium and V. parvifolium have deep simple epicotyl morphophysiological dormancy, C(1b)B (root)-C(3) (epicotyl). Warm stratification was required to break the first part of physiological dormancy (PD), thereby allowing embryo growth and subsequently radicle emergence. Although cold stratification was not required for differentiation of the epicotyl--plumule, it was required to break the second part of PD, thereby allowing the shoot to emerge in spring.

Deep simple epicotyl morphophysiological dormancy in seeds of two Viburnum species, with special reference to shoot growth and development inside the seed

PubMed Central

Chien, Ching-Te; Chen, Shun-Ying; Tsai, Ching-Chu; Baskin, Jerry M.; Baskin, Carol C.; Kuo-Huang, Ling-Long

2011-01-01

Background and Aims In seeds with deep simple epicotyl morphophysiological dormancy, warm and cold stratification are required to break dormancy of the radicle and shoot, respectively. Although the shoot remains inside the seed all winter, little is known about its growth and morphological development prior to emergence in spring. The aims of the present study were to determine the temperature requirements for radicle and shoot emergence in seeds of Viburnum betulifolium and V. parvifolium and to monitor growth of the epicotyl, plumule and cotyledons in root-emerged seeds. Methods Fresh and pre-treated seeds of V. betulifolium and V. parvifolium were incubated under various temperature regimes and monitored for radicle and shoot emergence. Growth of the epicotyl and cotyledons at different stages was observed with dissecting and scanning electron microscopes. Key Results The optimum temperature for radicle emergence of seeds of both species, either kept continuously at a single regime or exposed to a sequence of regimes, was 20/10 °C. GA3 had no effect on radicle emergence. Cold stratification (5 °C) was required for shoot emergence. The shoot apical meristem in fresh seeds did not form a bulge until the embryo had grown to the critical length for radicle emergence. After radicle emergence, the epicotyl–plumule and cotyledons grew slowly at 5 and 20/10 °C, and the first pair of true leaves was initiated. However, the shoot emerged only from seeds that received cold stratification. Conclusions Seeds of V. betulifolium and V. parvifolium have deep simple epicotyl morphophysiological dormancy, C1bB (root)–C3 (epicotyl). Warm stratification was required to break the first part of physiological dormancy (PD), thereby allowing embryo growth and subsequently radicle emergence. Although cold stratification was not required for differentiation of the epicotyl–plumule, it was required to break the second part of PD, thereby allowing the shoot to emerge in spring. PMID:21562028

Sympathetic Innervation of Cold-Activated Brown and White Fat in Lean Young Adults

PubMed Central

Mangner, Tom J.; Leonard, William R.; Kumar, Ajay; Granneman, James G.

2017-01-01

Recent work in rodents has demonstrated that basal activity of the local sympathetic nervous system is critical for maintaining brown adipocyte phenotypes in classic brown adipose tissue (BAT) and white adipose tissue (WAT). Accordingly, we sought to assess the relationship between sympathetic innervation and cold-induced activation of BAT and WAT in lean young adults. Methods: Twenty adult lean normal subjects (10 women and 10 men; mean age ± SD, 23.3 ± 3.8 y; body mass index, 23.7 ± 2.5 kg/m2) underwent 11C-meta-hydroxyephedrin (11C-HED) and 15O-water PET imaging at rest and after exposure to mild cold (16°C) temperature. In addition, 18F-FDG images were obtained during the cold stress condition to assess cold-activated BAT mass. Subjects were divided into 2 groups (high BAT and low BAT) based on the presence of 18F-FDG tracer uptake. Blood flow and 11C-HED retention index (RI, an indirect measure of sympathetic innervation) were calculated from dynamic PET scans at the location of BAT and WAT. Whole-body daily energy expenditure (DEE) during rest and cold stress was measured by indirect calorimetry. Tissue level oxygen consumption (MRO2) was determined and used to calculate the contribution of cold-activated BAT and WAT to daily DEE. Results: 18F-FDG uptake identified subjects with high and low levels of cold-activated BAT mass (high BAT, 96 ± 37 g; low-BAT, 16 ± 4 g). 11C-HED RI under thermoneutral conditions significantly predicted 18F-FDG uptake during cold stress (R2 = 0.68, P < 0.01). In contrast to the significant increase of 11C-HED RI during cold in BAT (2.42 ± 0.85 vs. 3.43 ± 0.93, P = 0.02), cold exposure decreased the 11C-HED RI in WAT (0.44 ± 0.22 vs. 0.41 ± 0.18) as a consequence of decreased perfusion (1.22 ± 0.20 vs. 1.12 ± 0.16 mL/100 g/min). The contribution of WAT to whole-body DEE was approximately 150 kcal/d at rest (149 ± 52 kcal/d), which decreased to approximately 100 kcal/d during cold (102 ± 47 kcal/d). Conclusion: The level of sympathetic innervation, as determined by 11C-HED RI, can predict levels of functional BAT. Overall, blood flow is the best independent predictor of 11C-HED RI and 18F-FDG uptake across thermoneutral and cold conditions. In contrast to BAT, cold stress reduces blood flow and 18F-FDG uptake in subcutaneous WAT, indicating that the physiologic response is to reduce heat loss rather than to generate heat. PMID:27789721

Effects of water immersion on posttraining recovery in Australian footballers.

PubMed

Elias, George P; Varley, Matthew C; Wyckelsma, Victoria L; McKenna, Michael J; Minahan, Clare L; Aughey, Robert J

2012-12-01

The authors investigated the efficacy of a single exposure to 14 min of cold-water immersion (COLD) and contrast water therapy (CWT) on posttraining recovery in Australian football (AF). Fourteen AF players participated in 3 wk of standardized training. After week 1 training, all players completed a passive recovery (PAS). During week 2, COLD or CWT was randomly assigned. Players undertook the opposing intervention in week 3. Repeat-sprint ability (6 × 20 m), countermovement and squat jumps, perceived muscle soreness, and fatigue were measured pretraining and over 48 h posttraining. Immediately posttraining, groups exhibited similar performance and psychometric declines. At 24 h, repeat-sprint time had deteriorated by 4.1% for PAS and 1.0% for CWT but was fully restored by COLD (0.0%). At 24 and 48 h, both COLD and CWT attenuated changes in mean muscle soreness, with COLD (0.6 ± 0.6 and 0.0 ± 0.4) more effective than CWT (1.9 ± 0.7 and 1.0 ± 0.7) and PAS having minimal effect (5.5 ± 0.6 and 4.0 ± 0.5). Similarly, after 24 and 48 h, COLD and CWT both effectively reduced changes in perceived fatigue, with COLD (0.6 ± 0.6 and 0.0 ± 0.6) being more successful than CWT (0.8 ± 0.6 and 0.7 ± 0.6) and PAS having the smallest effect (2.2 ± 0.8 and 2.4 ± 0.6). AF training can result in prolonged physical and psychometric deficits persisting for up to 48 h. For restoring physical-performance and psychometric measures, COLD was more effective than CWT, with PAS being the least effective. Based on these results the authors recommend that 14 min of COLD be used after AF training.

Non-linear effects of drought under shade: reconciling physiological and ecological models in plant communities.

PubMed

Holmgren, Milena; Gómez-Aparicio, Lorena; Quero, José Luis; Valladares, Fernando

2012-06-01

The combined effects of shade and drought on plant performance and the implications for species interactions are highly debated in plant ecology. Empirical evidence for positive and negative effects of shade on the performance of plants under dry conditions supports two contrasting theoretical models about the role of shade under dry conditions: the trade-off and the facilitation hypotheses. We performed a meta-analysis of field and greenhouse studies evaluating the effects of drought at two or more irradiance levels on nine response variables describing plant physiological condition, growth, and survival. We explored differences in plant response across plant functional types, ecosystem types and methodological approaches. The data were best fit using quadratic models indicating a humped-back shape response to drought along an irradiance gradient for survival, whole plant biomass, maximum photosynthetic capacity, stomatal conductance and maximal photochemical efficiency. Drought effects were ameliorated at intermediate irradiance, becoming more severe at higher or lower light levels. This general pattern was maintained when controlling for potential variations in the strength of the drought treatment among light levels. Our quantitative meta-analysis indicates that dense shade ameliorates drought especially among drought-intolerant and shade-tolerant species. Wet tropical species showed larger negative effects of drought with increasing irradiance than semiarid and cold temperate species. Non-linear responses to irradiance were stronger under field conditions than under controlled greenhouse conditions. Non-linear responses to drought along the irradiance gradient reconciliate opposing views in plant ecology, indicating that facilitation is more likely within certain range of environmental conditions, fading under deep shade, especially for drought-tolerant species.

Contributions of white and brown adipose tissues and skeletal muscles to acute cold-induced metabolic responses in healthy men

PubMed Central

Blondin, Denis P; Labbé, Sébastien M; Phoenix, Serge; Guérin, Brigitte; Turcotte, Éric E; Richard, Denis; Carpentier, André C; Haman, François

2015-01-01

Cold exposure stimulates the sympathetic nervous system (SNS), triggering the activation of cold-defence responses and mobilizing substrates to fuel the thermogenic processes. Although these processes have been investigated independently, the physiological interaction and coordinated contribution of the tissues involved in producing heat or mobilizing substrates has never been investigated in humans. Using [U-13C]-palmitate and [3-3H]-glucose tracer methodologies coupled with positron emission tomography using 11C-acetate and 18F-fluorodeoxyglucose, we examined the relationship between whole body sympathetically induced white adipose tissue (WAT) lipolysis and brown adipose tissue (BAT) metabolism and mapped the skeletal muscle shivering and metabolic activation pattern during a mild, acute cold exposure designed to minimize shivering response in 12 lean healthy men. Cold-induced increase in whole-body oxygen consumption was not independently associated with BAT volume of activity, BAT oxidative metabolism, or muscle metabolism or shivering intensity, but depended on the sum of responses of these two metabolic tissues. Cold-induced increase in non-esterified fatty acid (NEFA) appearance rate was strongly associated with the volume of metabolically active BAT (r = 0.80, P = 0.005), total BAT oxidative metabolism (r = 0.70, P = 0.004) and BAT glucose uptake (r = 0.80, P = 0.005), but not muscle glucose metabolism. The total glucose uptake was more than one order of magnitude greater in skeletal muscles compared to BAT during cold exposure (674 ± 124 vs. 12 ± 8 μmol min−1, respectively, P < 0.001). Glucose uptake demonstrated that deeper, centrally located muscles of the neck, back and inner thigh were the greatest contributors of muscle glucose uptake during cold exposure due to their more important shivering response. In summary, these results demonstrate for the first time that the increase in plasma NEFA appearance from WAT lipolysis is closely associated with BAT metabolic activation upon acute cold exposure in healthy men. In humans, muscle glucose utilization during shivering contributes to a much greater extent than BAT to systemic glucose utilization during acute cold exposure. PMID:25384777

The effect of fasting and body reserves on cold tolerance in 2 pit-building insect predators.

PubMed

Scharf, Inon; Daniel, Alma; MacMillan, Heath Andrew; Katz, Noa

2017-06-01

Pit-building antlions and wormlions are 2 distantly-related insect species, whose larvae construct pits in loose soil to trap small arthropod prey. This convergent evolution of natural histories has led to additional similarities in their natural history and ecology, and thus, these 2 species encounter similar abiotic stress (such as periodic starvation) in their natural habitat. Here, we measured the cold tolerance of the 2 species and examined whether recent feeding or food deprivation, as well as body composition (body mass and lipid content) and condition (quantified as mass-to-size residuals) affect their cold tolerance. In contrast to other insects, in which food deprivation either enhanced or impaired cold tolerance, prolonged fasting had no effect on the cold tolerance of either species, which had similar cold tolerance. The 2 species differed, however, in how cold tolerance related to body mass and lipid content: although body mass was positively correlated with the wormlion cold tolerance, lipid content was a more reliable predictor of cold tolerance in the antlions. Cold tolerance also underwent greater change with ontogeny in wormlions than in antlions. We discuss possible reasons for this lack of effect of food deprivation on both species' cold tolerance, such as their high starvation tolerance (being sit-and-wait predators).

Comparative analysis of the cold acclimation and freezing tolerance capacities of seven diploid Brachypodium distachyon accessions

PubMed Central

Colton-Gagnon, Katia; Ali-Benali, Mohamed Ali; Mayer, Boris F.; Dionne, Rachel; Bertrand, Annick; Do Carmo, Sonia; Charron, Jean-Benoit

2014-01-01

Background and Aims Cold is a major constraint for cereal cultivation under temperate climates. Winter-hardy plants interpret seasonal changes and can acquire the ability to resist sub-zero temperatures. This cold acclimation process is associated with physiological, biochemical and molecular alterations in cereals. Brachypodium distachyon is considered a powerful model system to study the response of temperate cereals to adverse environmental conditions. To date, little is known about the cold acclimation and freezing tolerance capacities of Brachypodium. The main objective of this study was to evaluate the cold hardiness of seven diploid Brachypodium accessions. Methods An integrated approach, involving monitoring of phenological indicators along with expression profiling of the major vernalization regulator VRN1 orthologue, was followed. In parallel, soluble sugars and proline contents were determined along with expression profiles of two COR genes in plants exposed to low temperatures. Finally, whole-plant freezing tests were performed to evaluate the freezing tolerance capacity of Brachypodium. Key Results Cold treatment accelerated the transition from the vegetative to the reproductive phase in all diploid Brachypodium accessions tested. In addition, low temperature exposure triggered the gradual accumulation of BradiVRN1 transcripts in all accessions tested. These accessions exhibited a clear cold acclimation response by progressively accumulating proline, sugars and COR gene transcripts. However, whole-plant freezing tests revealed that these seven diploid accessions only have a limited capacity to develop freezing tolerance when compared with winter varieties of temperate cereals such as wheat and barley. Furthermore, little difference in terms of survival was observed among the accessions tested despite their previous classification as either spring or winter genotypes. Conclusions This study is the first to characterize the freezing tolerance capacities of B. distachyon and provides strong evidence that some diploid accessions such as Bd21 have a facultative growth habit. PMID:24323247

Temperature-induced changes in neuromuscular function: central and peripheral mechanisms.

PubMed

Goodman, D; Hancock, P A; Runnings, D W; Brown, S L

1984-10-01

Three series of experimental tests were conducted on subjects under both elevated and depressed thermal conditions. Tripartite series consisted of whole-body immersion excepting the head, whole-body immersion excepting the head and response limb, and immersion of the discrete-response limb. Measures of physiological and behavioural responses were made at sequential .4 degrees C changes during whole-body immersions and approximately 5 degrees C changes of water temperature during the immersion of a limb only. Results suggested that velocity of nerve conduction decreased with thermal depression. Premotor, motor, simple, and choice reaction times varied differentially as a function of the hot and cold conditions. Implications of these differential effects on neuromuscular function are examined with respect to person-machine performance in artificially induced or naturally occurring extremes of ambient temperature.

Mortality related to extreme temperature for 15 cities in northeast Asia.

PubMed

Chung, Yeonseung; Lim, Youn-Hee; Honda, Yasushi; Guo, Yue-Liang Leon; Hashizume, Masahiro; Bell, Michelle L; Chen, Bing-Yu; Kim, Ho

2015-03-01

Multisite time-series studies for temperature-related mortality have been conducted mainly in the United States and Europe, but are lacking in Asia. This multisite time-series study examined mortality related to extreme temperatures (both cold and hot) in Northeast Asia, focusing on 15 cities of 3 high-income countries. This study includes 3 cities in Taiwan for 1994-2007, 6 cities in Korea for 1992-2010, and 6 cities in Japan for 1972-2009. We used 2-stage Bayesian hierarchical Poisson semiparametric regression to model the nonlinear relationship between temperature and mortality, providing city-specific and country-wide estimates for cold and heat effects. Various exposure time frames, age groups, and causes of death were considered. Cold effects had longer time lags (5-11 days) than heat effects, which were immediate (1-3 days). Cold effects were larger for cities in Taiwan, whereas heat effects were larger for cities in Korea and Japan. Patterns of increasing effects with age were observed in both cold and heat effects. Both cold and heat effects were larger for cardiorespiratory mortality than for other causes of death. Several city characteristics related to weather or air pollution were associated with both cold and heat effects. Mortality increased with either cold or hot temperature in urban populations of high-income countries in Northeast Asia, with spatial variations of effects among cities and countries. Findings suggest that climate factors are major contributors to the spatial heterogeneity of effects in this region, although further research is merited to identify other factors as determinants of variability.

Metabolic shifts in the Antarctic fish Notothenia rossii in response to rising temperature and PCO2

PubMed Central

2012-01-01

Introduction Ongoing ocean warming and acidification increasingly affect marine ecosystems, in particular around the Antarctic Peninsula. Yet little is known about the capability of Antarctic notothenioid fish to cope with rising temperature in acidifying seawater. While the whole animal level is expected to be more sensitive towards hypercapnia and temperature, the basis of thermal tolerance is set at the cellular level, with a putative key role for mitochondria. This study therefore investigates the physiological responses of the Antarctic Notothenia rossii after long-term acclimation to increased temperatures (7°C) and elevated PCO2 (0.2 kPa CO2) at different levels of physiological organisation. Results For an integrated picture, we analysed the acclimation capacities of N. rossii by measuring routine metabolic rate (RMR), mitochondrial capacities (state III respiration) as well as intra- and extracellular acid–base status during acute thermal challenges and after long-term acclimation to changing temperature and hypercapnia. RMR was partially compensated during warm- acclimation (decreased below the rate observed after acute warming), while elevated PCO2 had no effect on cold or warm acclimated RMR. Mitochondrial state III respiration was unaffected by temperature acclimation but depressed in cold and warm hypercapnia-acclimated fish. In both cold- and warm-exposed N. rossii, hypercapnia acclimation resulted in a shift of extracellular pH (pHe) towards more alkaline values. A similar overcompensation was visible in muscle intracellular pH (pHi). pHi in liver displayed a slight acidosis after warm normo- or hypercapnia acclimation, nevertheless, long-term exposure to higher PCO2 was compensated for by intracellular bicarbonate accumulation. Conclusion The partial warm compensation in whole animal metabolic rate indicates beginning limitations in tissue oxygen supply after warm-acclimation of N. rossii. Compensatory mechanisms of the reduced mitochondrial capacities under chronic hypercapnia may include a new metabolic equilibrium to meet the elevated energy demand for acid–base regulation. New set points of acid–base regulation under hypercapnia, visible at the systemic and intracellular level, indicate that N. rossii can at least in part acclimate to ocean warming and acidification. It remains open whether the reduced capacities of mitochondrial energy metabolism are adaptive or would impair population fitness over longer timescales under chronically elevated temperature and PCO2. PMID:23075125

Effects of Localized Cold Therapy on Pain in Postoperative Spinal Fusion Patients: A Randomized Control Trial.

PubMed

Quinlan, Patricia; Davis, Jack; Fields, Kara; Madamba, Pia; Colman, Lisa; Tinca, Daniela; Cannon Drake, Regina

Cold therapy used in the sports medicine settings has been found to be effective in reducing postoperative pain; however, there are limited studies that examine the effect of cold therapy on postoperative pain in patients with posterior lumbar spinal fusion. The purpose of this study was to determine the effects of cold on postoperative spine pain and add to the body of knowledge specific to practical application of cold therapy in the spine surgery setting. Researchers used a two-group randomized control design to evaluate the effects of local cold therapy on postoperative pain and analgesia use after lumbar spinal fusion surgery. The primary outcome was postoperative pain. Secondary outcomes included analgesia use and perceived benefit of cold therapy. The intervention (cold) group had a marginally greater reduction in mean Numerical Rating Scale score across all 12 pain checks (M ± SD = -1.1 ± 0.8 points reduction vs. -1.0 ± 0.8 points reduction, p = .589). On average, the intervention group used less morphine equivalents (M ± SD = 12.6 ± 31.5 vs. 23.7 ± 40.0) than the control group across pain checks seven to 12 (p = .042). This study provides additional evidence to support the use of cold therapy as an adjuvant pain management strategy to optimize pain control and reduce opioid consumption following spine fusion surgical procedures.

Echinacea purpurea: A Proprietary Extract of Echinacea purpurea Is Shown to be Safe and Effective in the Prevention of the Common Cold.

PubMed

Ross, Stephanie Maxine

2016-01-01

The research study in this review represents the largest clinical trial to date that evaluated the safety and efficacy of Echinacea purpurea for prophylactic treatment of the common cold, in addition to investigating its risk-benefit in a long-term treatment period. The clinical application of the proprietary standardized Echinacea purpurea extract(Echinaforce) demonstrated efficacy as a preventive cold treatment option over a 4-month duration. This study showed that Echinacea’s long-term prevention was associated with a reduction in the total number of cold episodes, a reduction in the number of days with colds, and a reduction in cold episodes requiring additional medication. Furthermore, the Echinacea test agent inhibited virally confirmed colds, exhibited maximal effects on recurrent infections, and demonstrated that its preventive effects increased relative to therapy compliance and adherence to the protocol. In summary, Echinacea purpurea when taken as recommended for the prevention of the common cold appears to provide a positive risk to benefit ratio.

Supportive treatment for children with the common cold.

PubMed

Ballengee, Cortney R; Turner, Ronald B

2014-02-01

This review summarizes recent developments in the supportive treatment of common cold symptoms in children. Conventional common cold therapies are no longer recommended for use in young children because of safety concerns. There are no studies that convincingly demonstrate the efficacy of any therapy for treatment of common cold symptoms in children less than 6 years of age and it is unlikely studies that establish efficacy can be done. Recent studies report a significant effect of probiotics on the occurrence of common cold illnesses in children, and studies in animals provide a plausible mechanism of action. These data suggest that the use of probiotics may have promise for the prevention of common cold illnesses in children. The effect of treatment on the severity of common cold symptoms cannot be accurately assessed with current study designs. In the absence of convincing evidence of efficacy, treatment of young children with symptomatic therapies cannot be recommended. Preliminary data suggest a small, beneficial effect of probiotics for the prevention of common cold illness.

Role of cold water and beta-effect in the formation of the East Korean Warm Current in the East/Japan Sea: a numerical experiment

NASA Astrophysics Data System (ADS)

Kim, Yong-Yub; Cho, Yang-Ki; Kim, Young Ho

2018-06-01

The contributions of bottom cold water and planetary β-effect to the formation of the East Korean Warm Current (EKWC), the western boundary current in the East/Japan Sea (EJS), were evaluated using an idealized three-dimensional numerical model. The model results suggest that the bottom cold water and, to a lesser extent, the planetary β-effect both contribute to the formation of the EKWC. The cold water functions as the bottom of the upper layer, to control the EKWC via conservation of potential vorticity. It is known that cold waters, such as the North Korean Cold Water and Korea Strait Bottom Cold Water often observed during summer along the southwestern coast of the EJS, originate from the winter convection in the northern area. Observational studies consistently show that the EKWC strengthens in summer when the cold water extends further south along the western boundary.

Memantine effects on liver and adrenal gland of rats exposed to cold stress

PubMed Central

2011-01-01

Background Memantine attenuates heart stress due cold stress, however, no study focused its effects on liver and adrenal gland. We evaluated its effects on lipid depletion in adrenal gland and glycogen depletion in liver of rats exposed to cold stress. Methods Male rats divided into 4 groups: 1)Control (CON); 2)Memantine (MEM); 3)Induced cold stress (IH) and; 4)Induced cold stress memantine (IHF). Memantine were administrated by gavage (20 mg/kg/day) during eight days. Cold stress were performed during 4 hours once at - 8°C. Lipid and glycogen depletion were presented as its intensity levels. Results Rats exposed to cold stress presented the highest glycogen (p < 0.001) and lipid depletion (p < 0.001) in liver and adrenal gland, respectively. We noted that memantine significantly reduced lipid depletion in adrenal gland and glycogen depletion in liver. Conclusion Memantine prevented glycogen depletion in liver and lipid depletion in adrenal gland of rats under a cold stress condition. PMID:21255456

Physiological limitation at alpine treeline: relationships of threshold responses of conifers to their establishment patterns

NASA Astrophysics Data System (ADS)

Germino, M. J.; Lazarus, B.; Castanha, C.; Moyes, A. B.; Kueppers, L. M.

2014-12-01

An understanding of physiological limitations to tree establishment at alpine treeline form the basis for predicting how this climate-driven boundary will respond to climate shifts. Most research on this topic has focused on limitations related to carbon balance and growth of trees. Carbon balance could limit survival and establishment primarily through slow-acting, chronic means. We asked whether tree survival and thus establishment patterns reflect control by chronic effects in comparison to acute, threshold responses, such as survival of frost events. Seedling survivorship patterns were compared to thresholds in freezing (temperature causing leaf freezing, or freezing point, FP; and physiological response to freezing) and water status (turgor loss point, TLP; and related physiological adjustments). Subject seedlings were from forest, treeline, and alpine sites in the Alpine Treeline Warming Experiment in Colorado, and included limber and lodgepole pine (a low-elevation species), and Engelmann Spruce. Preliminary results show survival increases with seedling age, but the only corresponding increase in stress acclimation was photosynthetic resistance to freezing and TLP, not FP. Differences in survivorship among the species were not consistent with variation in FP but they generally agreed with variation in photosynthetic resistance to deep freezing and to early-season drought avoidance. Mortality of limber pine increased 35% when minimum temperatures decreased below -9C, which compares with FPs of >-8.6C, and about 1/3 of its mortality occurred during cold/wet events, particularly in the alpine. The other major correlate of mortality is midsummer drying events, as previously reported. Also in limber pine, the TLP for year-old seedlings (-2.5 MPa) corresponded with seasonal-drought mortality. In summary, we show several examples of correspondence in physiological thresholds to mortality events within a species, although the relationships are not strong. Across species, photosynthetic resistance to freezing and early-season drought avoidance related well to mortality patterns. These results are generally more supportive of the role of chronic rather than acute climate effects in broad patterns of tree seedling establishment at treeline.

Zinc acetate lozenges for treating the common cold: an individual patient data meta-analysis.

PubMed

Hemilä, Harri; Petrus, Edward J; Fitzgerald, James T; Prasad, Ananda

2016-11-01

The aim of this study was to determine whether the allergy status and other characteristics of common cold patients modify the effects of zinc acetate lozenges. We had available individual patient data for three randomized placebo-controlled trials in which zinc acetate lozenges were administered to common cold patients. We used both one stage and two stage meta-analysis to estimate the effects of zinc lozenges. The total number of common cold patients was 199, the majority being females. Eighty percent of them fell into the age range 20-50 years. One third of the patients had allergies. The one stage meta-analysis gave an overall estimate of 2.73 days (95% CI 1.8, 3.3 days) shorter colds by zinc acetate lozenge usage. The two stage meta-analysis gave an estimate of 2.94 days (95% CI 2.1, 3.8 days) reduction in common cold duration. These estimates are to be compared with the 7 day average duration of colds in the three trials. The effect of zinc lozenges was not modified by allergy status, smoking, baseline severity of the common cold, age, gender or ethnic group. Since the effects of zinc acetate lozenges were consistent between the compared subgroups, the overall estimates for effect seemed applicable over a wide range of common cold patients. While the optimal composition of zinc lozenges and the best frequency of their administration should be further investigated, given the current evidence of efficacy, common cold patients may be encouraged to try zinc lozenges for treating their colds. © 2016 The British Pharmacological Society.

Zinc lozenges and the common cold: a meta-analysis comparing zinc acetate and zinc gluconate, and the role of zinc dosage.

PubMed

Hemilä, Harri

2017-05-01

To compare the efficacy of zinc acetate lozenges with zinc gluconate lozenges in common cold treatment and to examine the dose-dependency of the effect. Meta-analysis. Placebo-controlled zinc lozenge trials, in which the zinc dose was > 75 mg/day. The pooled effect of zinc lozenges on common cold duration was calculated by using inverse-variance random-effects method. Seven randomised trials with 575 participants with naturally acquired common colds. Duration of the common cold. The mean common cold duration was 33% (95% CI 21% to 45%) shorter for the zinc groups of the seven included trials. Three trials that used lozenges composed of zinc acetate found that colds were shortened by 40% and four trials that used zinc gluconate by 28%. The difference between the two salts was not significant: 12 percentage points (95% CI: -12 to + 36). Five trials used zinc doses of 80-92 mg/day, common cold duration was reduced by 33%, and two trials used zinc doses of 192-207 mg/day and found an effect of 35%. The difference between the high-dose and low-dose zinc trials was not significant: 2 percentage points (95% CI: -29 to + 32). Properly composed zinc gluconate lozenges may be as effective as zinc acetate lozenges. There is no evidence that zinc doses over 100 mg/day might lead to greater efficacy in the treatment of the common cold. Common cold patients may be encouraged to try zinc lozenges for treating their colds. The optimal lozenge composition and dosage scheme need to be investigated further.

Zinc acetate lozenges for treating the common cold: an individual patient data meta‐analysis

PubMed Central

Petrus, Edward J.; Fitzgerald, James T.; Prasad, Ananda

2016-01-01

Aims The aim of this study was to determine whether the allergy status and other characteristics of common cold patients modify the effects of zinc acetate lozenges. Methods We had available individual patient data for three randomized placebo‐controlled trials in which zinc acetate lozenges were administered to common cold patients. We used both one stage and two stage meta‐analysis to estimate the effects of zinc lozenges. Results The total number of common cold patients was 199, the majority being females. Eighty percent of them fell into the age range 20–50 years. One third of the patients had allergies. The one stage meta‐analysis gave an overall estimate of 2.73 days (95% CI 1.8, 3.3 days) shorter colds by zinc acetate lozenge usage. The two stage meta‐analysis gave an estimate of 2.94 days (95% CI 2.1, 3.8 days) reduction in common cold duration. These estimates are to be compared with the 7 day average duration of colds in the three trials. The effect of zinc lozenges was not modified by allergy status, smoking, baseline severity of the common cold, age, gender or ethnic group. Conclusion Since the effects of zinc acetate lozenges were consistent between the compared subgroups, the overall estimates for effect seemed applicable over a wide range of common cold patients. While the optimal composition of zinc lozenges and the best frequency of their administration should be further investigated, given the current evidence of efficacy, common cold patients may be encouraged to try zinc lozenges for treating their colds. PMID:27378206

The effects of exercise and cold exposure on mitochondrial biogenesis in skeletal muscle and white adipose tissue

PubMed Central

Chung, Nana; Park, Jonghoon; Lim, Kiwon

2017-01-01

[Purpose] The purpose of this study was to determine whether exercise or/and cold exposure regulate mitochondria biogenesis-related gene expression in soleus and inguinal adipose tissue of mice. [Methods] Forty ICR 5-week old male mice were divided into four groups: thermoneutrality-untrained (23 ± 1 °C in room temperature, n=10), cold-water immersion (24 ± 1 °C, n=10), exercise in neutral temperature (34 ± 1 °C, n=10), and exercise in cold temperature (24 ± 1 °C, n=10). The mice performed swimming exercise (30 min to 60 min, 5 times) for 8 weeks. After 8 weeks, we confirmed mitochondrial biogenesis-related gene expression changes for peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), nuclear respiratory factors 1 (NRF1), and mitochondrial transcription factor A (Tfam) in soleus muscle and inguinal adipose tissue, and the related protein expression in soleus muscle. [Results] In soleus muscle, PGC-1α expression significantly increased in response to cold exposure (p = 0.006) and exercise (p = 0.05). There was also significant interaction between exercise and cold exposure (p = 0.005). Only exercise had a significant effect on NRF1 relative expression (p=0.001). Neither cold exposure nor the interaction showed significant effects (p = 0.1222 and p = 0.875, respectively). Relative Tfam expression did not show any significant effect from exercise. In inguinal adipose tissue, relative PGC-1α expression did not significantly change in any group. NRF1 expression showed a significant change from exercise (p = 0.01) and cold exposure (p = 0.011). There was also a significant interaction between exercise and cold exposure (p = 0.000). Tfam mRNA expression showed a significant effect from exercise (p=0.000) and an interaction between exercise and cold exposure (p=0.001). Only temperature significantly affected PGC-1α protein levels (p=0.045). Neither exercise nor the interaction were significant (p = 0.397 and p = 0.292, respectively). NRF1 protein levels did not show a significant effect in any experimental treatments. Tfam protein levels showed a significant effect in the exercise group (p=0.012), but effects of neither cold exposure nor the interaction were significant (p = 0.085 and p=0.374, respectively). [Conclusion] Exercise and cold exposure promoted increased expression of mitochondrial biogenesis- related genes in soleus muscle. Only cold exposure had a significant effect on PGC-1α protein expression and only exercise had a significant effect on Tfam protein expression. In inguinal adipose tissue, there was interaction between exercise and cold exposure in expression of mitochondrial biogenesis-related genes. PMID:28715885

Impacts of cold weather on all-cause and cause-specific mortality in Texas, 1990-2011.

PubMed

Chen, Tsun-Hsuan; Li, Xiao; Zhao, Jing; Zhang, Kai

2017-06-01

Cold weather was estimated to account for more than half of weather-related deaths in the U.S. during 2006-2010. Studies have shown that cold-related excessive mortality is especially relevant with decreasing latitude or in regions with mild winter. However, only limited studies have been conducted in the southern U.S. The purpose of our study is to examine impacts of cold weather on mortality in 12 major Texas Metropolitan Areas (MSAs) for the 22-year period, 1990-2011. Our study used a two-stage approach to examine the cold-mortality association. We first applied distributed lag non-linear models (DLNM) to 12 major MSAs to estimate cold effects for each area. A random effects meta-analysis was then used to estimate pooled effects. Age-stratified and cause-specific mortalities were modeled separately for each MSA. Most of the MSAs were associated with an increased risk in mortality ranging from 0.1% to 5.0% with a 1 °C decrease in temperature below the cold thresholds. Higher increased mortality risks were generally observed in MSAs with higher average daily mean temperatures and lower latitudes. Pooled effect estimate was 1.58% (95% Confidence Interval (CI) [0.81, 2.37]) increase in all-cause mortality risk with a 1 °C decrease in temperature. Cold wave effects in Texas were also examined, and several MSAs along the Texas Gulf Coast showed statistically significant cold wave-mortality associations. Effects of cold on all-cause mortality were highest among people over 75 years old (1.86%, 95% CI [1.09, 2.63]). Pooled estimates for cause-specific mortality were strongest in myocardial infarction (4.30%, 95% CI [1.18, 7.51]), followed by respiratory diseases (3.17%, 95% CI [0.26, 6.17]) and ischemic heart diseases (2.54%, 95% CI [1.08, 4.02]). In conclusion, cold weather generally increases mortality risk significantly in Texas, and the cold effects vary with MSAs, age groups, and cause-specific deaths. Copyright © 2017 Elsevier Ltd. All rights reserved.

Autonomic responses to cold face stimulation in sickle cell disease: a time-varying model analysis.

PubMed

Chalacheva, Patjanaporn; Kato, Roberta M; Sangkatumvong, Suvimol; Detterich, Jon; Bush, Adam; Wood, John C; Meiselman, Herbert; Coates, Thomas D; Khoo, Michael C K

2015-07-14

Sickle cell disease (SCD) is characterized by sudden onset of painful vaso-occlusive crises (VOC), which occur on top of the underlying chronic blood disorder. The mechanisms that trigger VOC remain elusive, but recent work suggests that autonomic dysfunction may be an important predisposing factor. Heart-rate variability has been employed in previous studies, but the derived indices have provided only limited univariate information about autonomic cardiovascular control in SCD. To circumvent this limitation, a time-varying modeling approach was applied to investigate the functional mechanisms relating blood pressure (BP) and respiration to heart rate and peripheral vascular resistance in healthy controls, untreated SCD subjects and SCD subjects undergoing chronic transfusion therapy. Measurements of respiration, heart rate, continuous noninvasive BP and peripheral vascular resistance were made before, during and after the application of cold face stimulation (CFS), which perturbs both the parasympathetic and sympathetic nervous systems. Cardiac baroreflex sensitivity estimated from the model was found to be impaired in nontransfused SCD subjects, but partially restored in SCD subjects undergoing transfusion therapy. Respiratory-cardiac coupling gain was decreased in SCD and remained unchanged by chronic transfusion. These results are consistent with autonomic dysfunction in the form of impaired parasympathetic control and sympathetic overactivity. As well, CFS led to a significant reduction in vascular resistance baroreflex sensitivity in the nontransfused SCD subjects but not in the other groups. This blunting of the baroreflex control of peripheral vascular resistance during elevated sympathetic drive could be a potential factor contributing to the triggering of VOC in SCD. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Conceptual framework of the eco-physiological phases of insect diapause development justified by transcriptomic profiling

PubMed Central

Štětina, Tomáš; Poupardin, Rodolphe; Korbelová, Jaroslava; Bruce, Alexander William

2017-01-01

Insects often overcome unfavorable seasons in a hormonally regulated state of diapause during which their activity ceases, development is arrested, metabolic rate is suppressed, and tolerance of environmental stress is bolstered. Diapausing insects pass through a stereotypic succession of eco-physiological phases termed “diapause development.” The phasing is varied in the literature, and the whole concept is sometimes criticized as being too artificial. Here we present the results of transcriptional profiling using custom microarrays representing 1,042 genes in the drosophilid fly, Chymomyza costata. Fully grown, third-instar larvae programmed for diapause by a photoperiodic (short-day) signal were assayed as they traversed the diapause developmental program. When analyzing the gradual dynamics in the transcriptomic profile, we could readily distinguish distinct diapause developmental phases associated with induction/initiation, maintenance, cold acclimation, and termination by cold or by photoperiodic signal. Accordingly, each phase is characterized by a specific pattern of gene expression, supporting the physiological relevance of the concept of diapause phasing. Further, we have dissected in greater detail the changes in transcript levels of elements of several signaling pathways considered critical for diapause regulation. The phase of diapause termination is associated with enhanced transcript levels in several positive elements stimulating direct development (the 20-hydroxyecdysone pathway: Ecr, Shd, Broad; the Wnt pathway: basket, c-jun) that are countered by up-regulation in some negative elements (the insulin-signaling pathway: Ilp8, PI3k, Akt; the target of rapamycin pathway: Tsc2 and 4EBP; the Wnt pathway: shaggy). We speculate such up-regulations may represent the early steps linked to termination of diapause programming. PMID:28720705

Reaction Norms in Natural Conditions: How Does Metabolic Performance Respond to Weather Variations in a Small Endotherm Facing Cold Environments?

PubMed Central

Petit, Magali; Vézina, François

2014-01-01

Reaction norms reflect an organisms' capacity to adjust its phenotype to the environment and allows for identifying trait values associated with physiological limits. However, reaction norms of physiological parameters are mostly unknown for endotherms living in natural conditions. Black-capped chickadees (Poecile atricapillus) increase their metabolic performance during winter acclimatization and are thus good model to measure reaction norms in the wild. We repeatedly measured basal (BMR) and summit (Msum) metabolism in chickadees to characterize, for the first time in a free-living endotherm, reaction norms of these parameters across the natural range of weather variation. BMR varied between individuals and was weakly and negatively related to minimal temperature. Msum varied with minimal temperature following a Z-shape curve, increasing linearly between 24°C and −10°C, and changed with absolute humidity following a U-shape relationship. These results suggest that thermal exchanges with the environment have minimal effects on maintenance costs, which may be individual-dependent, while thermogenic capacity is responding to body heat loss. Our results suggest also that BMR and Msum respond to different and likely independent constraints. PMID:25426860