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PubMed1983

Vascular participation in deep cold pain.

As the magnitude of cold pain probably depends on blood flow and thus on internal limb temperature, the activated nociceptors should be close to or within the walls of veins. This hypothesis was tested by injecting small quantities (20 ml) of cold saline into an empty vein of the hand in 16 subjects. Saline temperatures below 26 degrees C elicited pure cold sensations whereas temperatures below 20 degrees C evoked both cold and pain sensations. Pain was mainly described as deep and it tended to radiate along the veins. With saline of 5 degrees C the pain tolerance level of several subjects was reached. Pain always appeared after cold and it disappeared before or together with cold. The results can be explained on the basis of two types of vascular receptors: a sensitive specific cold receptor and a nociceptor with a threshold around 20 degrees C.

Adult↗
PubMed1998

Accumulation of an acidic dehydrin in the vicinity of the plasma membrane during cold acclimation of wheat

Expression of the acidic dehydrin gene wcor410 was found to be associated with the development of freezing tolerance in several Gramineae species. This gene is part of a family of three homologous members, wcor410, wcor410b, and wcor410c, that have been mapped to the long arms of the homologous group 6 chromosomes of hexaploid wheat. To gain insight into the function of this gene family, antibodies were raised against the WCOR410 protein and affinity purified to eliminate cross-reactivity with the WCS120 dehydrin-like protein of wheat. Protein gel blot analyses showed that the accumulation of WCOR410 proteins correlates well with the capacity of each cultivar to cold acclimate and develop freezing tolerance. Immunoelectron microscope analyses revealed that these proteins accumulate in the vicinity of the plasma membrane of cells in the sensitive vascular transition area where freeze-induced dehydration is likely to be more severe. Biochemical fractionation experiments indicated that WCOR410 is a peripheral protein and not an integral membrane protein. These results provide direct evidence that a subtype of the dehydrin family accumulates near the plasma membrane. The properties, abundance, and localization of these proteins suggest that they are involved in the cryoprotection of the plasma membrane against freezing or dehydration stress. We propose that WCOR410 plays a role in preventing the destabilization of the plasma membrane that occurs during dehydrative conditions.

Journal Article↗
PubMed1988

The efficacy of hypnosis- and relaxation-induced analgesia on two dimensions of pain for cold pressor and electrical tooth pulp stimulation.

This study evaluated the efficacy of hypnosis- and relaxation-induced suggestions for analgesia for reducing the strength and unpleasantness dimensions of pain evoked by noxious tooth pulp stimulation and by cold pressor stimulation. The Tellegen Absorption Questionnaire was used to assess hypnotic susceptibility for 28 subjects in order to match treatment groups according to sex and susceptibility scores. Tooth pulp stimulation consisted of a 1 sec train of 1 msec pulses at a frequency of 100 Hz, applied at 20 sec intervals to the central incisor. Six stimuli, selected between subject's pain and tolerance thresholds, were presented 3 times each in random order. Cold pressor stimulation consisted of forearm immersion in a circulating water bath maintained at 0-1 degrees C. Subjects made threshold determinations of pain and tolerance and used Visual Analogue Scales to rate the strength and the unpleasantness of both noxious stimuli before and after receiving either hypnosis- or relaxation-induced analgesia. There were no significant differences in pain reductions between hypnosis- and relaxation-induced interventions. However, the percent reduction in both strength and unpleasantness varied significantly as a function of the type of pain. Both hypnosis and relaxation significantly reduced the strength and the unpleasantness of tooth pulp stimulation, but only the unpleasantness dimension of cold pressor pain. The pain reductions were not correlated with subjects' hypnotic susceptibility levels. The results indicate that the extent and the quality of the analgesia produced by these cognitive-based therapies vary not only according to subjects' characteristics and the efficacy of the intervention, but also according to the nature of the noxious stimuli. Tooth pulp and cold pressor stimulation represent qualitatively different stimuli with respect to both the type of nerves activated and the mode of stimulus application. Discrete, randomly presented levels of noxious electrical stimulation to the teeth activate predominantly small fibers and produce brief pain sensations that vary unpredictably in intensity. In contrast, continuous cold stimulation to the forearm activates a variety of nociceptive and non-nociceptive fibers and produces progressive cold and pain sensations with a predictable increase in intensity from cold sensations to paresthesia and severe pain.

Adult↗
PubMed2000

Functional analysis of oxidative stress-activated mitogen-activated protein kinase cascade in plants.

Despite the recognition of H(2)O(2) as a central signaling molecule in stress and wounding responses, pathogen defense, and regulation of cell cycle and cell death, little is known about how the H(2)O(2) signal is perceived and transduced in plant cells. We report here that H(2)O(2) is a potent activator of mitogen-activated protein kinases (MAPKs) in Arabidopsis leaf cells. Using epitope tagging and a protoplast transient expression assay, we show that H(2)O(2) can activate a specific Arabidopsis mitogen-activated protein kinase kinase kinase, ANP1, which initiates a phosphorylation cascade involving two stress MAPKs, AtMPK3 and AtMPK6. Constitutively active ANP1 mimics the H(2)O(2) effect and initiates the MAPK cascade that induces specific stress-responsive genes, but it blocks the action of auxin, a plant mitogen and growth hormone. The latter observation provides a molecular link between oxidative stress and auxin signal transduction. Finally, we show that transgenic tobacco plants that express a constitutively active tobacco ANP1 orthologue, NPK1, display enhanced tolerance to multiple environmental stress conditions without activating previously described drought, cold, and abscisic acid signaling pathways. Thus, manipulation of key regulators of an oxidative stress signaling pathway, such as ANP1/NPK1, provides a strategy for engineering multiple stress tolerance that may greatly benefit agriculture.

Arabidopsis↗
PubMed2005

Roles of the CBF2 and ZAT12 transcription factors in configuring the low temperature transcriptome of Arabidopsis.

Summary The CBF cold response pathway has a prominent role in cold acclimation. The pathway includes action of three transcription factors, CBF1, 2 and 3 (also known as DREB1b, c and a, respectively), that are rapidly induced in response to low temperature followed by expression of the CBF-targeted genes (the CBF regulon) that act in concert to increase plant-freezing tolerance. The results of transcriptome profiling and mutagenesis experiments, however, indicate that additional cold response pathways exist and may have important roles in life at low temperature. To further understand the roles that the CBF proteins play in configuring the low temperature transcriptome and to identify additional transcription factors with roles in cold acclimation, we used the Affymetrix GeneChip containing probe sets for approximately 24,000 Arabidopsis genes to define a core set of cold-responsive genes and to determine which genes were targets of CBF2 and 6 other transcription factors that appeared to be coordinately regulated with CBF2. A total of 514 genes were placed in the core set of cold-responsive genes, 302 of which were upregulated and 212 downregulated. Hierarchical clustering and bioinformatic analysis indicated that the 514 cold-responsive transcripts could be assigned to one of seven distinct expression classes and identified multiple potential novel cis-acting cold-regulatory elements. Eighty-five cold-induced genes and eight cold-repressed genes were assigned to the CBF2 regulon. An additional nine cold-induced genes and 15 cold-repressed genes were assigned to a regulon controlled by ZAT12. Of the 25 core cold-induced genes that were most highly upregulated (induced over 15-fold), 19 genes (84%) were induced by CBF2 and another two genes (8%) were regulated by both CBF2 and ZAT12. Thus, the large majority (92%) of the most highly induced genes belong to the CBF and ZAT12 regulons. Constitutive expression of ZAT12 in Arabidopsis caused a small, but reproducible, increase in freezing tolerance, indicating a role for the ZAT12 regulon in cold acclimation. In addition, ZAT12 downregulated the expression of the CBF genes indicating a role for ZAT12 in a negative regulatory circuit that dampens expression of the CBF cold response pathway.

Acclimatization↗
PubMed2004

Promoters from a cold-adapted bacterium: definition of a consensus motif and molecular characterization of UP regulative elements.

Although low-temperature tolerant micro-organisms were discovered long ago, limited information is still available on the transcription machinery in cold-adapted bacteria. This knowledge represents a necessary background for the investigation of the adaptation of gene-expression mechanisms at low temperatures. The recent development of a shuttle genetic system for the transformation of the cold-adapted Gram-negative bacterium Pseudoalteromonas haloplanktis strain TAC125 has made possible the isolation of the psychrophilic promoters described in this paper. TAC125 genomic DNA fragments were cloned in the shuttle vector and the promoter-containing recombinant clones were selected for their ability to express a promoter-less lacZ gene. The nucleotide sequence of several selected inserts and the transcription start points of the transcribed m-RNAs were determined. A promoter consensus sequence for Pseudoalteromonas haloplanktis TAC125 was proposed on the basis of a sequence comparison between the various active promoters. Furthermore, the identification and the functional characterization of two UP elements from this cold-adapted bacterium are also reported.

Adaptation, Physiological↗
PubMed1998

Temperature and NaCl-tolerance of rock-inhabiting meristematic fungi.

Black meristematic fungi together with lichens and cyanobacteria dominate the micro-flora of rock surfaces in arid and semi-arid environments of hot and cold deserts. This study shows that rock inhabiting meristematic fungi are extremely tolerant against high temperatures, desiccation and osmotic stress. Their temperature tolerance increases with increasing dehydration of the fungal thallus. Air dried mycelia of black yeasts stand temperatures up to 120 degrees C for at least 0.5 hours. As response to high temperatures multilayered cell walls are developed and trehalose is accumulated whereas the intracellular glycerol regulates the osmotic potential under NaCl stress. Strains from rock in moderate climate (North Germany) show the same tolerance than those isolated from the Mediterranean area. Hortaea werneckii--hitherto only described as agent of human Tinea nigra--is shown to be the most tolerant rock inhabiting species tested. Meristematic fungi cannot be pre-adapted to higher growth temperatures by increased incubation temperatures. Considering the results of this study the justification of the term 'stress' is discussed with regard to rock inhabiting fungi and their natural environment. Consequences for conservation treatments of monuments decayed by meristematic fungi are discussed on the basis of the ecophysiological properties of the fungi.

Desiccation↗
PubMed1998

Tolerance induction ameliorates allograft vasculopathy in rat aortic transplants. Influence of Fas-mediated apoptosis.

Based on successful induction of donor-specific unresponsiveness by alloantigenic stimulation in several animal models of acute rejection, we hypothesized that similar immune manipulations would also inhibit the evolution of chronic rejection and transplant vasculopathy. To induce immune tolerance, DA rats received a PVG heart allograft and were immunosuppressed with cyclosporine for 30 d. At day 100 the animals were challenged with a PVG aortic allograft after either 1 or 18 h of cold ischemia. 8 wk after the aortic transplantation, the grafts were investigated for morphological changes, infiltrating cells, apoptosis, and Fas-Fas ligand expression. Control allografts showed advanced transplant arteriosclerosis, whereas tolerance-induced aortic allografts displayed reduced neointimal formation, less medial atrophy, fewer apoptotic cells, and fewer Fas- and FasL-expressing cells. Prolonged ischemic storage time did not profoundly alter the morphological changes of the allografts. Fas expression was found in T cells, macrophages, vascular smooth muscle cells, and endothelial cells, whereas FasL was expressed mainly by T cells and macrophages. FasL mRNA expression was evident throughout the entire allograft wall. In conclusion, induction of allospecific tolerance can effectively prevent transplant arteriosclerosis. Cold ischemia damage does not abrogate the beneficial effect of tolerance, but creates a separate identity of mainly endothelial lesions. Furthermore, Fas-mediated apoptosis appears to be involved in the pathological lesions seen in chronic rejection.

Animals↗
PubMed1987

Influence of chemical and environmental stressors on acute cadmium toxicity.

Previous investigations have demonstrated that the cytosolic protein metallothionein (MT) is induced not only by exposure to certain heavy metals but also by a variety of other factors, including environmental stress. While MT synthesis has been observed with exposure to cold temperatures, there is a paucity of data concerning the influence of cold on heavy-metal toxicity. The present investigation focused on the influence of metal and cold pretreatments on the acute toxicity of cadmium. Mortalities of 80% and 100% were observed for mice orally administered challenge doses of 100 mg Cd/kg and 150 mg Cd/kg, respectively. To determine a protective cadmium pretreatment dose, animals were administered 2.5, 5, 10, 20, 25, and 50 mg Cd/kg 24 h prior to cadmium challenge. In animals pretreated with 10 mg Cd/kg, mortalities of 20% and 70% were observed with the respective challenge doses. Immediately following cold stress (4 degrees C, 12 h), mortalities of 30% and 90% were observed with cadmium challenge doses of 100 and 150 mg Cd/kg, respectively. Significant correlations were demonstrated between induced hepatic MT concentrations and cadmium pretreatment (r = 0.99), as well as cold pretreatment (r = 0.87). Results of this investigation indicate that stressors, such as cold, influence the acute toxicity of cadmium to the same magnitude as metal pretreatment. This induced tolerance to cadmium was attributed, in part, to the induction of MT synthesis. Furthermore, the induced levels of MT resulting from cold stress may confound the simplistic approach of using MT as a biological monitor of occupational exposure to cadmium.

Animals↗
PubMed2005

Expressed sequence tags from the Yukon ecotype of Thellungiella reveal that gene expression in response to cold, drought and salinity shows little overlap.

Thellungiella salsuginea (also known as T. halophila) is a close relative of Arabidopsis that is very tolerant of drought, freezing, and salinity and may be an appropriate model to identify the molecular mechanisms underlying abiotic stress tolerance in plants. We produced 6578 ESTs, which represented 3628 unique genes (unigenes), from cDNA libraries of cold-, drought-, and salinity-stressed plants from the Yukon ecotype of Thellungiella. Among the unigenes, 94.1% encoded products that were most similar in amino acid sequence to Arabidopsis and 1.5% had no match with a member of the family Brassicaceae. Unigenes from the cold library were more similar to Arabidopsis sequences than either drought- or salinity-induced sequences, indicating that latter responses may be more divergent between Thellungiella and Arabidopsis. Analysis of gene ontology using the best matched Arabidopsis locus showed that the Thellungiella unigenes represented all biological processes and all cellular components, with the highest number of sequences attributed to the chloroplast and mitochondria. Only 140 of the unigenes were found in all three abiotic stress cDNA libraries. Of these common unigenes, 70% have no known function, which demonstrates that Thellungiella can be a rich resource of genetic information about environmental responses. Some of the ESTs in this collection have low sequence similarity with those in Genbank suggesting that they may encode functions that may contribute to Thellungiella's high degree of stress tolerance when compared with Arabidopsis. Moreover, Thellungiella is a closer relative of agriculturally important Brassica spp. than Arabidopsis, which may prove valuable in transferring information to crop improvement programs.

Algorithms↗
PubMed1994

A randomized controlled trial of cold-adapted and inactivated vaccines for the prevention of influenza A disease.

A double-blind, randomized controlled trial over 5 years compared the safety, immunogenicity, and efficacy of cold-adapted and inactivated influenza A vaccines in 5210 normal subjects. Both vaccines were well tolerated. Inactivated vaccine significantly increased hemagglutination inhibition antibody titers. Significant titer rises were also noted after cold-adapted vaccine but of lesser magnitude than with inactivated vaccine. The efficacy of inactivated vaccine in preventing culture-positive influenza was 76% (95% confidence interval [CI], 58%-87%) for H1N1 disease and 74% (95% CI, 52%-86%) for H3N2; for cold-adapted vaccine, 85% (95% CI, 70%-92%) and 58% (95% CI, 29%-75%), respectively. The efficacy of inactivated vaccine in preventing a four-fold rise in antibody titer over the influenza season was 69% (95% CI, 61%-76%) for H1N1 and 73% (95% CI, 65%-79%) for H3N2; for cold-adapted vaccine, 54% (95% CI, 44%-62%) and 32% (95% CI, 17%-44%), respectively. Cold-adapted and inactivated influenza vaccines are safe and effective for preventing influenza A disease.

Administration, Intranasal↗
PubMed1988

Cold Acclimation in Arabidopsis thaliana.

The abilities of two races of Arabidopsis thaliana L. (Heyn), Landsberg erecta and Columbia, to cold harden were examined. Landsberg, grown at 22 to 24 degrees C, increased in freezing tolerance from an initial 50% lethal temperature (LT(50)) of about -3 degrees C to an LT(50) of about -6 degrees C after 24 hours at 4 degrees C; LT(50) values of -8 to -10 degrees C were achieved after 8 to 9 days at 4 degrees C. Similar increases in freezing tolerance were obtained with Columbia. In vitro translation of poly(A(+)) RNA isolated from control and cold-treated Columbia showed that low temperature induced changes in the population of translatable mRNAs. An mRNA encoding a polypeptide of about 160 kilodaltons (isoelectric point about 4.5) increased markedly after 12 to 24 h at 4 degrees C, as did mRNAs encoding four polypeptides of about 47 kilodaltons (isoelectric points ranging from 5-5.5). Incubation of Columbia callus tissue at 4 degrees C also resulted in increased levels of the mRNAs encoding the 160 kilodalton polypeptide and at least two of the 47 kilodalton polypeptides. In vivo labeling experiments using Columbia plants and callus tissue indicated that the 160 kilodalton polypeptide was synthesized in the cold and suggested that at least two of the 47 kilodalton polypeptides were produced. Other differences in polypeptide composition were also observed in the in vivo labeling experiments, some of which may be the result of posttranslational modifications of the 160 and 47 kilodalton polypeptides.

Journal Article↗
PubMed1999

Stress-induced expression of cyclophilins in proembryonic masses of Digitalis lanata does not protect against freezing/thawing stress.

Using proembryonic masses (PEMs) of Digitalis lanata Erh., it was demonstrated that cold, hormonal or osmotic stress, which increased freezing tolerance during cryopreservation, induced an increasing level of two peptidyl-prolyl-cis/transisomerases (PPIases). The difference in pI (9.2 +/- 0.2 and 9.5 +/- 0.2, +/- SD; n = 3) allowed the separation of the two enzymes by free-flow isoelectrophoresis. Both were inhibited by cyclosporin A and thus belong to the cyclophilin family of PPIases. The enzymes differed slightly in their substrate specificity and their relative molecular masses of 18038 +/- 4 Da (D. lanataCyp18.0) and 18132 +/- 3 Da (D. lanataCyp18.1). Both cyclophilins were blocked N-terminally. Partial internal amino acid sequences from the two cyclophilins, with a length of 34 amino acids, displayed 82% sequence identity to each other. Pretreatment of PEMs with abscisic acid, sorbitol or a combination of both substances led to a 270 +/- 30% elevation of the total cytosolic cyclophilin concentration determined with a cyclophylin affinity sensor. During the first 4 d of pretreatment, the total PPIase activity was enhanced up to 230 +/- SD% compared with the control culture. The lag phase between maximal PPIase concentration after 4 d of pretreatment and maximal effect of freezing tolerance after 10 d of pretreatment indicated that increasing levels of cytosolic PPIases may be necessary to overcome the stress induced by hormones and osmotica during pretreatment but not to protect against freezing/thawing stress.

Adaptation, Physiological↗
PubMed1997

Trehalose-induced destabilization of interdigitated gel phase in dihexadecylphosphatidylcholine.

Trehalose is believed to have the ability to protect some organisms against low temperatures. To clarify the cryoprotective mechanism of trehalose, the structure and the phase behavior of fully hydrated dihexadecylphosphatidylcholine (DHPC) membranes in the presence of various concentrations of trehalose were studied by means of differential scanning calorimetry (DSC), static x-ray diffraction, and simultaneous x-ray diffraction and DSC measurements. The temperature of the interdigitated gel (Lbeta(i))-to-ripple (Pbeta') phase transition of DHPC decreases with a rise in trehalose concentration up to approximately 1.0 M. Above a trehalose concentration of approximately 1.0 M, no Lbeta(i) phase is observed. In this connection, the electron density profile calculated from the lamellar diffraction data in the presence of 1.6 M trehalose indicates that DHPC forms noninterdigitated bilayers below the P beta' phase. It was concluded that trehalose destabilizes the Lbeta(i) phase of DHPC bilayers. This suggests that trehalose reduces the area at the interface between the lipid and water. The relation between this effect of trehalose and a low temperature tolerance was discussed from the viewpoint of cold-induced denaturation of proteins.

Biophysical Phenomena↗