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PubMed2002

Changes in compositional parameters of tubers of potato (Solanum tuberosum) during low-temperature storage and their relationship to chip processing quality.

A four-year study of a number of compositional parameters of potato tubers during low-temperature storage was conducted to examine the compositional differences between cold-tolerant (low sugar-accumulating) and cold-sensitive (high sugar-accumulating) tubers in relation to potato chip processing quality. Compositional parameters analyzed included sucrose, reducing sugars, nitrogen, protein, ascorbic acid, and dry matter content. Pearson correlation analysis of the data illustrated that chip color was most closely correlated with reducing sugar concentration. Multiple regression analysis revealed that the relative contribution of each parameter to chip color varied greatly among the cultivars and selections evaluated and from season to season. This analysis demonstrates that the quantitative relationships between the measured compositional parameters and chip color were not sufficient to provide a general predictive index of chip color quality for tubers processed directly from low-temperature storage.

Ascorbic Acid↗
PubMed1980

Characteristics of Cold Acclimation and Deacclimation in Tuber-bearing Solanum Species.

The effect of temperatures on cold acclimation and deacclimation in foliage tissues was studied in Solanum commersonii (Oka 4583), a tuber-bearing potato. The threshold temperature for cold acclimation was about 12 C. In a temperature range of 2 to 12 C, the increase in hardiness was dependent on the acclimating temperature; the lower the acclimating temperature, the more hardiness achieved. A day/night temperature of 2 C, regardless of photoperiod, appeared to the optimum acclimating temperature for the Solanum species studied. A subfreezing temperature hardened plants less effectively. The maximum level of hardiness could be reached after 15 days of cold acclimation. However, it took only 1 day to deacclimate the hardened plants to a preacclimation level when plants were subjected to a warm regime from cold. The degree of deacclimation was dependent on the temperature of the warm regime.Based on cold tolerance and the capacity to acclimate to cold, tuber-bearing Solanum species could be grouped into five categories. Chilling injury was also observed in some of the tuber-bearing Solanum species.

Journal Article↗
PubMedDate not supplied

Skin microcirculation in patients with sequelae from local cold injuries.

The microcirculation in the skin was assessed in 31 patients with sequelae from local cold injuries (LCI) in the extremities. All patients reported cold intolerance 3-4 years after the primary cold injury, which they sustained during military service. The used methods were laser Doppler fluxmetry, transcutaneous oxygen tension (TCpO2) and vital capillaroscopy. Neurovascular reflexes were stimulated by deep inspiration, digital cuff occlusion of venous and arterial circulation, neck cooling with an ice bag and water immersion at 5 and 15 degrees C. Unaffected lower or upper extremities were also investigated as part of a search for generalized effects of LCI. During immersion in ice water the cold-induced vasodilation (CIVD or Lewis' 'hunting' reaction) was profoundly delayed or abolished in the affected limbs. These also showed the lowest skin temperatures after 15-20 min of immersion. Additionally, a delayed CIVD was found in the unaffected feet of patients with a previous hand injury. TCpO2 resting values were decreased in the patients, but oxygen reappearance time, oxygen recovery index, postocclusive reactive hyperemia and the venoarterial reflex were normal. No capillary abnormalities were found. In conclusion, LCI induces disturbances in the CIVD, impairs cold tolerance and increases the risk of future cold injuries. These data demonstrate disturbances of reflex mechanisms mediated by the central nervous system. Neurophysiologic factors seem to be more important than ischemic mechanisms in the pathophysiology of late sequelae from LCI.

Adult↗
PubMed2005

Metabolic responses to cold in subterranean crustaceans.

Changes in polyol, sugar and free amino acid (FAA) body contents were investigated in the aquatic, subterranean (i.e. hypogean) crustaceans Niphargus rhenorhodanensis and Niphargus virei and in a morphologically close aquatic, surface-dwelling (i.e. epigean) crustacean Gammarus fossarum acclimated to 12 degrees C, 3 degrees C and -2 degrees C. With decreasing temperature, G. fossarum significantly increased its alanine and glutamine levels, while trehalose body content was found to increase above control levels only at -2 degrees C. N. virei showed moderate increases of alanine and glycine, and no change in trehalose level was observed in this species. By contrast, N. rhenorhodanensis was the only species showing a significant rise in its total FAA pool, mainly explained by alanine, glycine, arginine and glutamine accumulations. This species also gradually increased its trehalose body content with decreasing temperature. Several cold-hardy ectotherms show metabolic responses to cold that are identical to those observed in N. rhenorhodanensis. A previous comparative study showed that the hypogean N. rhenorhodanensis exhibited a survival time (Lt50) at -2 degrees C that was 26.3 times and 2.6 times higher than the hypogean N. virei and the epigean G. fossarum, respectively. Thus, crustacean levels of FAA and trehalose were correlated with their respective cold tolerances. Such differences in metabolic responses to cold in both hypogean organisms were unexpected since they both live in thermally buffered biotopes. Considering the current distribution areas of the two subterranean crustaceans studied, we assume that the cold hardiness found in the hypogean N. rhenorhodanensis could be correlated with its biogeography history during the quaternary glaciations.

Acclimatization↗
PubMed2004

Dynamics of production of sexual forms in aphids: theoretical and experimental evidence for adaptive "coin-flipping" plasticity.

The best strategy for an organism to deal with unpredictable environmental conditions is a stochastic one, but it is not easy to distinguish it from nonadaptive randomness in phenotype production, and its convincing demonstrations are lacking. Here we describe a new method for detection of adaptive stochastic polyphenism and apply it to the following problem. In fall, each female of the bird cherry-oat aphid, Rhopalosiphum padi, faces a decision either to produce sexuals, which mate and lay cold-tolerant eggs, or to continue production of cold-sensitive parthenogenetic females, which potentially yields a higher population growth rate but is risky because a cold winter can kill all of her descendants. Using a simulation model, we show that global investment in sexual reproduction should be proportional to winter severity and that variance in the peak date of production of sexual individuals should depend on climate predictability. Both predictions are validated against standardized trap data on aphid flight accompanied by meteorological data, and the predictions support adaptive phenotypic plasticity.

Adaptation, Physiological↗
PubMed1989

Effects of cold-treatment on protein synthesis and mRNA levels in rice leaves.

The effects of cold on protein and RNA metabolism in leaves of rice (Oryza sativa L.) seedlings were investigated. Treatment with a diurnal cycle of 15/10 degrees C or 11/6 degrees C for up to 1 week resulted in progressive changes in the protein synthesis pattern after in vivo labeling of intact rice leaves with [(35)S]methionine. These changes were reversed when the seedlings were returned to normal growth temperatures. While de novo accumulation of several abundant proteins was suppressed, some polypeptides were consistently found to be cold-induced. Synthesis of ribulose 1,5-bisphosphate carboxylase (Rubisco) was drastically reduced after 7 days of cold. Using immunoprecipitation of Rubisco, evidence was obtained that the suppression was greater for the small subunit (over 90%) than for the large subunit (80%), indicating a partial loss of coordination in their synthesis. Preformed Rubisco as well as other cold-suppressed proteins were stable for up to 7 days at 11/6 degrees C. Cold-sensitive rice cultivars responded with similar but more drastic changes in the protein synthesis pattern when compared to cold-tolerant varieties. The suppression of Rubisco synthesis by cold was shown to result from reduced levels of the mRNAs encoding both subunits; their decrease paralleled the lower protein synthesis of each. The levels of other chloroplast-encoded mRNAs, especially psaB, and of the nuclear encoded chlorophyll a/b binding protein, also strongly decreased in the cold, whereas the transcripts of the mitochondrial genes apt9, coxIII, and most nuclear genes analyzed were unaffected or only slightly reduced. These data indicate that some chloroplast functions are disturbed during cold stress. One nuclear gene known to be induced by water stress and ABA (Rab21) was also found to be induced by cold treatment.

Journal Article↗
PubMed1997

Factors affecting the freeze tolerance of the hoverfly Syrphus ribesii (Diptera: syrphidae).

Larvae of Syrphus ribesii collected from overwintering sites in the U.K. are strongly freeze tolerant with 70% survival at -35 degrees C. The cold tolerance of laboratory reared insects increased with increasing periods of acclimation at 0 degrees C, with a concurrent rise in the supercooling point (SCP) from -6.8+/-0.1 to -5.1+/-0.3 degrees C. There was 50% survival in the most cold-hardy group 72h after brief exposures to -30 degrees C. The retention of gut contents caused a decrease in cold hardiness, with only 13% of larvae surviving 72h after exposure to -15 degrees C, with no subsequent pupation or emergence. Wet larvae had a significantly higher SCP (-5.0+/-0.2 degrees C) compared to dry larvae (-7.8+/-0.4 degrees C), although survival of larvae was similar in both groups. There was no nucleator activity in the haemolymph of field collected larvae. The importance of these findings are discussed in relation to the freeze tolerance strategy of S. ribesii.

Journal Article↗
PubMed2005

Hope against the cold: individual differences in trait hope and acute pain tolerance on the cold pressor task.

Hope theory (see Snyder, 1994) is presented as a useful framework for understanding reactions to pain. In Study 1, persons scoring higher on the trait Hope Scale (Snyder, Harris et al., 1991) kept their hands in the freezing water (of a cold pressor task) for significantly longer. In Study 2, the higher-hope males, and not females, as measured by both trait and state hope (Snyder, Sympson et al., 1996), recognized the onset of the pain threshold significantly later. Moreover, in Study 2, results showed that individual differences measures of optimism, self-efficacy, depression, and positive and negative affects did not relate to the pain onset and tolerance variables. The implications of hope as related to the pain process and related research are discussed.

Acute Disease↗
PubMed1994

A cold-induced gene from Medicago sativa encodes a bimodular protein similar to developmentally regulated proteins.

A new cold-regulated (COR) gene, msa CIC, was isolated by differential screening of a cDNA library from cold-acclimated crowns of alfalfa (Medicago sativa L. cv. Apica). Transcripts of msa CIC were not detectable in unacclimated alfalfa and accumulated to higher levels in cold-acclimated plants of the cold-tolerant cv. Apica than in those of the cold-sensitive cv. CUF-101. The DNA sequence analysis of a full-length cDNA clone revealed that msa CIC encodes for a putative protein (MSACIC) of 166 amino acids with distinct proline-rich and hydrophobic domains. Protein sequence comparisons indicated that MSACIC is similar to a group of bimodular proteins that are developmentally regulated in other plant species.

Adaptation, Biological↗
PubMed1986

Thermoregulatory control after upper extremity replantation.

Four patients with complete forearm amputations between the wrist and elbow were analyzed prospectively to determine the interrelationships of thermoregulation to pain, cold intolerance, arterial integrity, venous competence, motor nerve recovery, sensory nerve recovery, and time. Patients were examined at 6 weeks, 3 months, 6 months, 1 year, and 2 years after replantation. Vasomotor regulatory capacity was assessed by isolated cold-stress testing. Pain had diminished in all patients by 6 months to 1 year, regardless of other factors. Cold tolerance and normal thermoregulatory response, as indicated by cold-stress test performances, were temporally related to attainment of two-point sensory discrimination (p less than 0.05), or to motor nerve recovery (p less than 0.05), or to both.

Adolescent↗
PubMed1998

The effect of exercise training in cold on shivering and nonshivering thermogenesis in adult and aged C57BL/6J mice.

To understand the mechanisms of improvement of cold-induced heat production in aged mice following exercise training, the relative contributions of shivering and nonshivering thermogenesis to cold-induced metabolic responses were assessed in adult and aged C57BL/6J male mice, which inhabited sedentarily at room temperature, or were subjected either to a regimen of moderate intensity exercise training at 6 degrees C, or to sedentary repeated exposures to the same temperature. The main findings were that (1) aged mice had greater cold-induced nonshivering thermogenesis, but lower shivering than adult mice; (2) exercise training in a cold environment enhanced cold-induced nonshivering thermogenesis in adult mice, but suppressed it in aged animals; (3) exercise training in a cold environment increased shivering thermogenesis in both age groups, but this increase was much greater in aged mice; (4) the increase of cold-induced shivering thermogenesis was mainly responsible for increased cold tolerance in aged mice after exercise training in a cold environment.

Aging↗
PubMed2003

Cold induction of Arabidopsis CBF genes involves multiple ICE (inducer of CBF expression) promoter elements and a cold-regulatory circuit that is desensitized by low temperature.

The Arabidopsis CBF1, 2, and 3 genes (also known as DREB1b, c, and a, respectively) encode transcriptional activators that have a central role in cold tolerance. CBF1-3 are rapidly induced upon exposing plants to low temperature, followed by expression of CBF-targeted genes, the CBF regulon, resulting in an increase in plant freezing tolerance. At present, little is known about the cold-sensing mechanism that controls CBF expression. Results presented here indicate that this mechanism does not require a cold shock to bring about the accumulation of CBF transcripts, but instead, absolute temperature is monitored with a greater degree of input, i.e. lower temperature, resulting in a greater output, i.e. higher levels of CBF transcripts. Temperature-shift experiments also indicate that the cold-sensing mechanism becomes desensitized to a given low temperature, such as 4 degrees C, and that resensitization to that temperature requires between 8 and 24 h at warm temperature. Gene fusion experiments identified a 125-bp section of the CBF2 promoter that is sufficient to impart cold-responsive gene expression. Mutational analysis of this cold-responsive region identified two promoter segments that work in concert to impart robust cold-regulated gene expression. These sequences, designated ICEr1 and ICEr2 (induction of CBF expression region 1 or 2), were also shown to stimulate transcription in response to mechanical agitation and the protein synthesis inhibitor, cycloheximide.

Acclimatization↗
PubMed1992

[Improved thermogenesis during acute cold exposure in exercise-trained rats].

The present study was carried out to examine the effects of enhanced cold tolerance induced by exercise training on carbohydrate metabolism during cold exposure. Five-week-old male Wistar rats were divided into three groups. The warm-acclimated control group (WA) was exposed to the environment at 25 degrees C, and the cold-acclimated group (CA) was acclimated to cold by exposure to 5 degrees C. The exercise-trained group (ET) was controlled to run at the rate of 35 meters per minute for 9 weeks on a small driven treadmill. The degree of carbohydrate metabolism due to cold exposure significantly decreased with the drop in environmental temperature in the WA and CA groups, but did not change in the ET group. When glucose utilization was blocked with 2-deoxyglucose administration, oxygen consumption during cold exposure decreased in the WA and ET groups, but did not decrease in the CA group. The liver glycogen content decreased during cold exposure in the WA and ET groups, but there was no change in the CA group. It appeared that the fall of the plasma glucose level after the infusion of insulin was significantly greater in the ET and CA groups than in the WA group. These results indicate that the improved capacity for cold-induced thermogenesis in the ET group may be caused by enhanced carbohydrate metabolism.

Animals↗
PubMed2006

Low-temperature tolerance and genetic potential in wheat (Triticum aestivum L.): response to photoperiod, vernalization, and plant development.

It is frequently observed that winter habit types are more low-temperature (LT) tolerant than spring habit types. This raises the question of whether this is due to pleiotropic effects of the vernalization loci or to the linkage of LT-tolerance genes to these vernalization loci. Reciprocal near-isogenic lines (NILs) for alleles at the Vrn-A1 locus, Vrn-A1 and vrn-A1, determining spring and winter habit respectively, in two diverse genetic backgrounds of wheat (Triticum aestivum L.) were used to separate the effects of vernalization, photoperiod, and development on identical, or near identical, genetic backgrounds. The vrn-A1 allele in the winter lines allowed full expression of genotype dependent LT tolerance potential. The winter allele (vrn-A1) in a very cold tolerant genetic background resulted in 11 degrees C, or a 2.4-fold, greater LT tolerance compared to the spring allele. Similarly, the delay in development caused by short-day (SD) versus long-day (LD) photoperiod in the identical spring habit NIL resulted in an 8.5 degrees C or 2.1-fold, increase in LT tolerance. The duration of time in early developmental stages was shown to underlie full expression of genetic LT-tolerance potential. Therefore, pleiotropic effects of the vernalization loci can explain the association of LT tolerance and winter habit irrespective of either the proposed closely linked Fr-A1 or the more distant Fr-A2 LT-tolerance QTLs. Plant development progressively reduced LT-acclimation ability, particularly after the main shoot meristem had advanced to the double ridge reproductive growth stage. The Vrn-1 genes, or other members of the flowering induction pathway, are discussed as possible candidates for involvement in LT-tolerance repression.

Acclimatization↗
PubMedDate not supplied

Radical scavenging activity and oxidative modification of citrus dehydrin.

Dehydrins are ubiquitous proteins produced by plants in response to water stress. Their functions, however, are not fully understood. The overexpression of Citrus unshiu Marcov. dehydrin (CuCOR19) enhanced cold tolerance in transgenic plants by reducing lipid peroxidation promoted by cold stress, suggesting that the CuCOR19 protein directly scavenges radicals. In this paper, we report the radical scavenging activity and oxidative modification of CuCOR19. The hydroxyl radical generated by the Fe2+/H2O2 system and peroxyl radical generated from 2, 2'-azobis (2-amidinopropane) (AAPH) were scavenged by CuCOR19, but hydrogen peroxide and superoxide were not. The scavenging activity for the hydroxyl radical and peroxyl radical of CuCOR19 was more potent than that of mannitol, and approximately equal to that of serum albumin, which is known as an antioxidative protein in mammals. CuCOR19 was degraded by the hydroxyl radical and peroxyl radical in a time- and dose-dependent manner. Mannitol and thiourea inhibited the degradation. Analysis of the amino acid composition of CuCOR19 indicated that glycine, histidine, and lysine, which are major residues in many dehydrins, were targeted by the hydroxyl radical. These results suggest that CuCOR19 is a radical scavenging protein, and may reduce oxidative damage induced by water stress in plants.

Citrus↗
PubMed1981

Prostaglandin E1 infusions for vascular insufficiency in progressive systemic sclerosis.

Twelve patients with systemic sclerosis (SS) and severe Raynaud's phenomenon received infusions of prostaglandin E1 (PGE1) at a dose of 6-10 ng/kg/min, with either saline or 5% dextrose, for 72 hours in a single-blind cross-over study. The infusions were administered intravenously by centrally positioned catheters. Infusions were well tolerated with only mild side effects. Following the PGE1 infusion cold tolerance improved and attacks of Raynaud's phenomenon were less frequent, less severe, and shorter in duration. This subjective improvement was maintained for several weeks in most patients, and 2 noted healing of ischaemic ulcers. There was no significant change in objective measurements of hand function after either infusion. However, pain measured on a 10 cm visual analogue scale improved 2.19 cm with PGE1 and only 0.91 cm with normal saline (P less than 0.05). Temperature of the fingers and hands recorded by thermography did not change significantly with saline infusions, but did rise during PGE1 infusions (mean rise 2.0 degrees C at 48 hours, p less than 0.001), and was maintained when measured again 2 weeks later (mean rise 1.56 degrees C, p less 0.001). PGE1 may therefore be suitable treatment for Raynaud's phenomenon and the vascular insufficiency of systemic sclerosis and other connective tissue diseases.

Adult↗
PubMed1984

Effects of fasting and aminophylline on norepinephrine-stimulated non-shivering thermogenesis.

In an attempt to further elucidate the mechanisms of fasting-depressed maximum thermogenesis and cold tolerance, norepinephrine (NE)-stimulated non-shivering thermogenesis (NST) in cold-acclimated rats was used as a functional index of possible alterations in adrenergic efficacy after fasting. Fasting decreased the magnitude of maximum NE-Stimulated NST by 18.2% [6.87 +/- 0.47 Kcal (Kg X 75 X min)-1 well-fed vs. 5.81 +/- 0.39 Kcal (Kg X 75 X min)-1 fasted], but the apparent adrenergic binding affinity was not affected [Ke = 0.43 micrograms NE min-1 well-fed vs. 0.55 micrograms NE min-1 fasted]. Pretreatment with aminophylline [15 mg Kg-1, i.p.], a phosphodiesterase inhibitor, restored the fasting-depressed NE-stimulated NST to the fed level. The results suggest that the depression of maximum thermogenesis after fasting is not due to changes in adrenergic binding characteristics but to alteration in cAMP production/degradation, resulting in decreased substrate mobilization for thermogenesis.

Aminophylline↗
PubMed1989

Effect of electrical stimulation of "rewarding" areas of the hypothalamus on habituation and dishabituation to repeated mild cold exposures in C57BL/6J mice.

Four groups of 12-month-old C57BL/6J male mice had chronic electrodes implanted in the median forebrain bundle. In three groups the "rewarding" property of electrical stimulation was determined during a single 30-min session of self-stimulation (ISS) before the beginning of the experiment. In the fourth group this test was postponed until the end of experiment. Every two weeks for 12 weeks all animals were subjected to repeated 3-hr cold stress tests consisting of partial physical restraint at an ambient temperature of 10 degrees C. The time interval between tests No. 3 and No. 4 was intentionally delayed up to four weeks. During the 4-week interval, animals of one of the groups tested for ISS remained in their home cages; mice of the second ISS-tested group received daily 30-min sessions of brain stimulation; and animals of the third ISS-tested group were placed daily for 30 min in the experimental chamber where they had been tested for ISS previously but received no brain stimulation. Animals of the fourth group, which were not tested for ISS prior to the experiment, also were placed daily in the experimental chamber without brain stimulation. Repeated cold testing resulted in improvement of cold tolerance (decrease of the rate of decline of colonic temperature during cold exposure) in the second and third tests relative to the first cold test in all groups (cold habituation).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗