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Results for “Cold tolerance”

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At least 1,621 records · Page 90Linked to original sources
PubMed2004

Ectopic overexpression of tomato JERF3 in tobacco activates downstream gene expression and enhances salt tolerance.

The ethylene, jasmonic acid and osmotic signaling pathways respond to environmental stimuli and in order to understand how plants adapt to biotic and abiotic stresses it is important to understand how these pathways interact each other. In this paper, we report a novel ERF protein--jasmonate and ethylene-responsive factor 3 (JERF3)--that unites these pathways. JERF3, which functions as an in vivo transcription activator in yeast, binds to the GCC box, an element responsive to ethylene/JA signaling, as well as to DRE, a dehydration-responsive element that responds to dehydration, high salt and low-temperature. Expression of JERF3 in tomato is mainly induced by ethylene, JA, cold, salt or ABA. Constitutive expression of JERF3 in transgenic tobacco significantly activated expression of pathogenesis-related genes that contained the GCC box, resulting in enhanced tolerance to salt. These results indicate that JERF3 functions as a linker in ethylene- and osmotic stress-signaling pathways.

Abscisic Acid↗
PubMedDate not supplied

Effects of prazosin on hemodynamics and sympatho-adrenal activity in hypertensive patients.

We studied peripheral and central hemodynamics and plasma catecholamine levels in 12 previously untreated patients with essential hypertension before and during treatment with the alpha 1-adrenoceptor antagonist prazosin (9.8 +/- 1.1 mg/day for 3-6 weeks following dose titration) as a single drug. Prazosin did not alter intra-arterially recorded blood pressures in the group as a whole, in spite of adequate plasma levels (12.6 +/- 1.2 ng/ml). There were no changes in cardiac output, blood volume, systemic or forearm vascular resistance, or forearm venous tone at rest during treatment. The blood pressure response to prazosin was correlated to pretreatment systemic and forearm vascular resistances. Arterial adrenaline levels were unchanged, but noradrenaline levels increased from 1.30 +/- 0.10 to 1.85 +/- 0.20 nM (p less than 0.05). Both noradrenaline and blood pressure responses to isometric hand-grip exercise were delayed and reduced during treatment. The hemodynamic and plasma catecholamine responses to a cold pressor test and tilting (50% head-up during 10 min) were similar before and during treatment. Our results may be related to development of tolerance to the alpha-adrenoceptor blocking effect of prazosin during long-term treatment. The elevation of arterial noradrenaline levels suggests that increased sympathetic activity also may have opposed the hypotensive response to prazosin.

Adult↗
PubMed2005

Identification and immunogold localization of a novel bromegrass (Bromus inermis Leyss) peroxisome channel protein induced by ABA, cold and drought stresses, and late embryogenesis.

A cDNA (BG-15) was isolated through differential screening of a cDNA library made from an ABA-treated bromegrass (Bromus inermis Leyss) suspension cell culture. The 819 bp pair cDNA encoded a 174 amino acid polypeptide with a calculated molecular mass of 18.08 kD and isolectric point of 7.50. The deduced amino acid sequences for the cDNA were 29.5% and 32.6% homologous to the known amino acid-selective channel proteins of the chloroplastic outer membrane in pea and barley, but were highly homologous (55.6% to 83.2%) to the putative membrane channel proteins from rice and Arabidopsis. Immunogold localization demonstrated that the channel protein encoded by this cDNA was present on the peroxisome membrane. High stringency southern analysis revealed that 1 to 2 copies of the peroxisomal channel protein (PCP) genes were present in the bromegrass genome. Northern and Western blots revealed that the PCP gene was responsive to both cold and drought stresses, and was rapidly induced by ABA (75 microM). The transcript of the PCP gene also accumulated during late embryogenesis, but declined rapidly during germination. Data taken together, responsiveness of the PCP to cold and drought stresses, and accumulation during late embryogenesis suggest this novel peroxisomal channel protein is associated with sugar and fatty acid metabolism through fatty acid import or succinate export from peroxisome during desiccation tolerance and energy metabolism.

Abscisic Acid↗
PubMed1993

Low Temperature Induces the Accumulation of Alcohol Dehydrogenase mRNA in Arabidopsis thaliana, a Chilling-Tolerant Plant.

mRNA encoding alcohol dehydrogenase (ADH) increases in etiolated seedlings and leaves of Arabidopsis thaliana (L.) Heynh. upon exposure to low temperature. The analysis of this response after water stress and abscisic acid (ABA) treatments in Arabidopsis wild type and ABA-deficient and -insensitive mutants indicates that cold accumulation of ADH mRNA could be induced by both anaerobic metabolism and increase of ABA concentration resulting from low temperature exposure. By using one Arabidopsis ADH null mutant, we show that ADH activity is not required for successful development of freezing tolerance in this species.

Journal Article↗
PubMedDate not supplied

Chill tolerance in the tropical beetle Stenotarsus rotundus.

The tropical beetle Stenotarsus rotundus (Endomychidae) survived chilling at mildly low temperatures (above +5 degree C). With upper limit of cold injury zone (ULCIZ, the highest temperature that causes cold injury) well above freezing point, the supercooling ability (mean supercooling point - SCP; -11 degree C) has no cryoprotective importance. Mortality increases rapidly between -9 and +5 degree C, dependent on accumulated dose of chilling (sum of injurious temperatures - SIT; 2 degree-days below ULCIZ). The cold hardiness traits found in this species are by-products of deep diapause, and may serve as pre-adaptation for expansion into cooler regions.

Journal Article↗
PubMed2005

Open trial to assess aspects of safety and efficacy of a combined herbal cough syrup with ivy and thyme.

BACKGROUND AND OBJECTIVES: Changes in the symptoms of cough after treatment with a combined herbal preparation containing dry ivy leaf extract as main active ingredient, decoction of thyme and aniseed, and mucilage of marshmallow root (Weleda Hustenelixier, new formulation) and its tolerability were investigated in an open clinical trial ('Anwendungsbeleg'). PATIENTS AND METHODS: Between January and March 2004, 13 general practitioners recruited and treated 62 patients with a mean age of 50 years (range 16-89). The patients had irritating cough in consequence of common cold (n = 29), bronchitis (n = 20) or respiratory tract diseases with formation of viscous mucus (n = 15). The mean daily intake was 10 ml (range 7.5-15) of syrup, and the mean duration of treatment was 12 days (range 3-23 days). Treatment results were assessed on the basis of changes in the symptom scores for cough and expectoration. Safety was evaluated by means of an analysis of adverse events. In addition, efficacy and tolerability were analyzed from the judgments of the doctors and patients. RESULTS: At the final visit, all symptom scores showed an improvement as compared to baseline. Doctors and patients assessed efficacy as good or very good in 86% and 90% of the cases, respectively. Tolerability was assessed as good or very good by 97% of the doctors and patients. Only one adverse event was reported. However, a relation to the medication was classified to be unlikely. CONCLUSION: Considering the traditional use of ivy leaves, thyme herb, aniseed and marshmallow root in preparations for cough, the reduction in the symptom score as well as the good tolerability the investigated combined herbal cough syrup seems to alleviate cough in consequence of common cold, bronchitis or respiratory tract diseases with formation of mucus.

Adolescent↗
PubMed1987

Promotion of radioresistance by metallothionein induction prior to irradiation.

A striking radioresistance has been found in mice which were subjected to various pretreatments to induce metallothionein synthesis in the liver prior to irradiation. The tolerance to lethal damage from an LD50 level of radiation during a 30-day postirradiation period was demonstrated by a highly significant difference (P less than 0.01) in mortality rate between mice given subcutaneously manganese, cadmium, or zinc injection or surgical skin excision of mice and the control mice (no pretreatment). A typical loss in body weight that generally reached a peak 2 weeks after irradiation was observed in the control mice, but mice given a dose of 10 mg manganese per kilogram body weight showed a steady weight increase even a few days after irradiation. The normal level of metallothionein in mouse liver is 20 micrograms/g tissue. This level increased up to 70 micrograms/g tissue following irradiation at 6.3 Gy. Among irradiated mice, metallothionein levels in the liver increased approximately 200-800% after cadmium, manganese, or zinc injection compared to levels of irradiated mice without pretreatment. Mice undergoing 2 X 2-cm2 dermal excision also demonstrated a similar reduction of mortality and high metallothionein contents in liver, i.e., 150-400 micrograms/g. The present results, together with our previous findings (Matsubara et al., 1982, 1983, 1984; Matsubara, 1986), suggest that the body's protective mechanism against radiation strongly correlates with the biosynthesis of metallothionein or metallothionein itself acting as a scavenger of radiation-induced peroxides.

Acetates↗
PubMed2006

Functional and phylogenetic analysis of a DREB/CBF-like gene in perennial ryegrass (Lolium perenne L.).

The dehydration-responsive element binding proteins (DREB1)/C-repeat (CRT) binding factors (CBF) function as transcription factors and bind to the DRE/CRT cis-acting element (core motif: G/ACCGAC) commonly present in cold-regulated (COR) genes and subsequently upregulate the expression of such genes in Arabidopsis. We identified a DREB1A/CBF3-like gene, designated LpCBF3, from perennial ryegrass (Lolium perenne L.) by using RT-PCR and RACE (rapid amplification of cDNA end). The LpCBF3 gene contains all the conserved domains known to exist in other CBF genes. A comprehensive phylogenetic analysis using known and computationally identified CBF homologs in this study revealed that all monocot CBF genes are separately clustered from eudicot CBF genes and the LpCBF3 is the ortholog of rice OsDREB1A/CBF3 gene. Similar to other DREB1A/CBF3 homologs, expression of the LpCBF3 is induced by cold stress, but not by abscisic acid (ABA), drought, or salinity. Overexpression of the LpCBF3 cDNA in Arabidopsis induced expression of the Arabidopsis DREB1A/CBF3 target COR genes, COR15a and RD29A, without cold acclimation. Ion leakage in leaves of the overexpression transgenic plants was significantly reduced, an indication of enhanced freezing tolerance. Our data demonstrated that LpCBF3 not only resembles DREB/CBF genes of Arabidopsis, but is also capable of functioning as a transcriptional regulator in Arabidopsis, a species distant to the grass family.

Acclimatization↗
PubMed1997

Phospholipase A2 in human placental serum.

Intervillous blood was collected from term placentae at delivery, and sera were tested for phospholipase A2 under various experimental conditions. Enzyme activity was found to develop upon extended storage in the cold or at 37 degrees C. The enzyme is reversibly inhibited by dithiothreitol, requires Ca++ ions for activity, and tolerates various detergents. The apparent molecular weight is 42 kDa. In all these parameters the serum enzyme behaves similar to the 42 kDa phospholipase A2 which we recently purified to homogeneity from thoroughly washed placental tissue. Serum phospholipase A2 appears to be generated by proteolytic processing from a slightly larger inactive precursor which was detected immunochemically. Most likely this protein originates from fetal cells and may be released by membrane damage. We conclude that both placental serum and tissue harbour a novel type of phospholipase A2 which is distinct from cytosolic and secretory phospholipases A2. Preference for arachidonate containing substrate suggests a role in eicosanoid production within gestational tissues.

Blood↗
PubMed1997

Loss of analgesic effect of morphine due to coadministration of rifampin.

Methadone withdrawal symptoms have been reported in drug addicts treated with the tuberculostatic rifampin. Whereas this interaction can be explained by induction of phase I drug metabolism (CYP3A4), knowledge about induction of phase II metabolism (e.g., UDP-glucuronosyltransferases = UGTs) and its influence on drug effects in man, however, is very limited. The potent analgesic morphine is metabolized by more than one UGT to the active metabolite morphine-6-glucuronide and to morphine-3-glucuronide, which is devoid of analgesic activity. Thus, differential induction of UGTs involved in metabolism of morphine might lead to decreased or increased analgesic effects, depending on which UGT is preferentially induced. We therefore investigated the influence of the potent enzyme inducer rifampin on analgesic effects and pharmacokinetics of morphine, which is primarily eliminated by phase II metabolism. Ten healthy male volunteers participated in this double-blind, placebo-controlled study with double crossover design. Morphine (10 mg p.o.) and placebo were administered on two separate occasions before and near the end of 13 days of treatment with rifampin (600 mg/day). Blood samples were collected for 31 h. Morphine effects on pain sensation were determined using the cold pressor test. When morphine was given alone, the opioid elicited a significant increase in pain threshold and pain tolerance in comparison to placebo (P < or = 0.05). However, following administration of rifampin no analgesic effect of morphine was observed. In agreement, the area under the serum concentration-time curve (AUC) of morphine and the maximum serum concentration of morphine were considerably reduced during coadministration of rifampin (-27.7 +/- 19.3% and -40.7 +/- 27.1%; P < or = 0.01). Moreover, during treatment with rifampin a proportional reduction of AUCs of morphine-3-glucuronide (P < or = 0.01), morphine-6-glucuronide (P < or = 0.05) and morphine was observed. Since urinary recoveries of both morphine-3-glucuronide and morphine-6-glucuronide were also reduced during administration of rifampin, there is no evidence for a contribution of UGT induction to the observed interaction. In summary, a major drug interaction was observed between morphine and rifampin, which could not be attributed to induction of UGTs, but resulted in a complete loss of analgesic effects of the opioid.

Adult↗
PubMed1994

Comparison of heated water-filled mattress and space-heated room with infant incubator in providing warmth to low birthweight newborns.

BACKGROUND: Prevention of excessive heat loss is fundamental to survival of low birthweight (LBW) newborns. The use of infant incubators (INC) is beyond the resources of developing countries, and the space-heated room (SHR) has been the only feasible means of providing thermal protection to LBW newborns. Recently a thermostatically controlled, heated, water-filled mattress (HWM) has been developed as a potentially simpler and affordable alternative. METHODS: In a neonatal care ward of a referral hospital in Addis Ababa, 62 < 1 week old newborns, weighing 1000-1999 g, who were well enough to breathe comfortably in room air and tolerate oral feeds, were randomly allocated to INC, HWM or SHR and followed for 3 weeks. The level of cold stress as assessed by core-to-skin temperature gradient and the rate of weight gain were the main outcome measures. RESULTS: The level of cold stress was lowest in the INC, intermediate in the HWM and highest in the SHR. Relative to the INC group, the HWM group exhibited a modest increase in the occurrence of clinically important hyperthermic or hypothermic deviations in core temperature (rate ratio (RR) = 2.3; 95% CI: 0.9, 5.6), and the SHR displayed a definite increase (RR = 4.0; 95% CI: 1.7, 9.3). During the first week, the rate of weight gain was highest in the INC group (3.6 g/kg/day), lowest in the SHR group (-2.3 g/kg/day, P < 0.05 versus INC) and intermediate in the HWM group (1.6 g/kg/day, P > 0.1 versus INC). CONCLUSION: Care in the SHR produced clinically significant thermal stresses and was associated with deficient early neonatal growth, but the use of HWM may constitute a feasible and clinically acceptable alternative in providing warmth to LBW newborns during the neonatal period.

Beds↗
PubMed1974

Nuclear magnetic resonance of water in cold acclimating red osier dogwood stem.

The pulsed and continuous-wave nuclear magnetic resonance of water in cold-acclimating red osier dogwood (Cornus stolonifera Michx) stem showed reduced relaxation times and increased line width. The reduction of relaxation times suggests an over-all restriction in the motional characteristics of the water. The increased line width is not related to a molecular property of the water, but is useful in estimating the initiation of cold acclimation. Biphasic relaxation characteristics may be related to partitioning of the water at the cellular level. The liquid water content of the stem was a weak function of temperature between -25 and -55 C, corresponding to approximately 0.15 gram of water per gram of dry stem. The quantity of unfrozen water at subfreezing temperatures was not strongly dependent on the degree of cold acclimation. It is concluded that the ability of dogwood to survive low temperatures depends on its ability to tolerate diminished quantities of liquid water.

Journal Article↗
PubMed1982

Attention, distraction, and cold-pressor pain.

This article compares the effects of distracting oneself from, versus attending to, the sensations produced by cold-pressor stimulation. Experiment 1 revealed that distraction is a better coping strategy than attention to sensations when subjects are asked to report pain threshold and tolerance. Experiments 2 and 3 examined the hypothesis that distraction is effective because persons hold a commonsense belief in the benefits of distraction as a coping device. Neither experiment supported the commonsense hypothesis as an explanation for the findings of Experiment 1. In a final experiment, subjects were assigned to either a distraction, attention, or no-instructions condition and were asked to report their distress during a 4-minute cold-pressor trial. Distraction reduced distress early in the trial, but attention to sensations proved to be a superior strategy for the last 2 minutes of the trial. It is proposed that distraction and attention to sensations may be differentially effective depending on the duration of the painful stimulus. Possible mediating processes underlying the two strategies are discussed.

Attention↗
PubMed1984

Effects of acupuncture and transcutaneous electrical nerve stimulation on cold-induced pain in normal subjects.

The effects of acupuncture, transcutaneous electrical nerve stimulation (TENS) at high (100 Hz) and low (8 Hz) frequency and placebo on pain induced by cold immersion of the hand were studied in 46 young healthy male and female volunteers. Acupuncture produced significant elevations of pain threshold, while 100 Hz TENS or placebo had no effect. Eight Hertz TENS produced elevation of pain threshold with significant variation in response between individuals. There was some evidence that the L scale score of the Eysenck Personality Questionnaire predicted analgesic outcome for 8 Hz TENS. No significant relationship was found between baseline pain threshold or tolerance and personality variables.

Acupuncture Therapy↗
PubMed2006

[Effects of osmoconditioning on membrane lipid components and fatty acid content of cold-sensitive soybean seeds].

Cold-sensitive soybean (Glycisne max Zhonghuang No.22) seeds were used to investigate the effects of osmoconditioning for invigoration of seeds chilling tolerance and the changes in membrane lipid by thin layer chromatography and gas chromatography to disclose the role of membrane lipid played in imbibitional chilling resistance capacity. Results are as follows: being treated with 33% PEG6000, seeds germination index, vigor index and root dry weight presented the trend of upward as the osmocondition time prolonged. In 72 h, the percentage of unsaturated phospholipid (e.g. PC and PE) in soybean seed increased, composition of lipid fatty acid changed: the saturated fatty acid 16:0 content in PC, PE, PI significantly decreased, while unsaturated fatty acid 18:2 increased greatly, which led to increase index of unsaturation fatty acid of lipid. These changes were positively corrected with osmoconditioning time. After treated with PEG, membrane fluidity increased to provide precondition for preventing imbibitional chilling, keeping the integrity of membrane system and normal metabolism.

Chromatography, Gas↗
PubMed1996

Differential acute tolerance development to effects of nitrous oxide in humans.

The analgesic, subjective, and psychomotor effects of 0, 10, 20, 30, and 40% nitrous oxide in oxygen were studied in 10 volunteers to determine if acute tolerance developed differentially to these variables. In this prospective, randomized, crossover, double-blind study, volunteers inhaled either placebo (100% oxygen) or one of the aforementioned doses of nitrous oxide for 120 min. During this period, volunteers immersed their non-dominant forearm, for 3 min, in ice-cold water at 25, 70 and 115 min from the onset of the inhalation. At other prescribed time intervals throughout the session, mood and psychomotor performance were assessed. Subjects reported less pain intensity from the cold-water stimulus and reported the pain bothered them less as a function of increasing nitrous oxide dose; in addition, this analgesia was significantly less as the inhalation period progressed (i.e., acute tolerance). Some subjective effects of nitrous oxide that could be considered hedonic in nature (elation, drug liking) also showed evidence of acute tolerance. In contrast, other subjective effects and the psychomotor-impairing effects of nitrous oxide did not change significantly during the inhalation period (i.c., no acute tolerance). The differential acute tolerance observed in this study suggests that different effects of nitrous oxide may be mediated by different neurochemical substrates.

Adult↗