Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0009443 (cold)
 92,137 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Irreversible pulpitis has been associated with pain and an increase in the number of pulp inflammatory cells. Based on the action of nitric oxide (NO) elsewhere, NO may possibly participate in the sensory and autonomic innervation of the dental pulp, and may influence local inflammatory responses. The purpose of this study was to analyze normal and inflamed human dental pulp for the presence of NADPH-diaphorase (NADPH-d), as an index of NO system activity. Six non-carious second premolar pulp tissue samples were obtained from young patients who required extractions for orthodontic reasons and six inflamed samples were obtained from symptomatic carious second premolars clinically diagnosed with irreversible pulpitis. Pulp tissue was carefully removed, fixed by immersion in a cold 4% PFA buffered solution for 120 min, rinsed in cold phosphate buffer, and quickly-frozen for cryostat sectioning. Pulp tissue was sectioned perpendicularly to the vertical axis of the tooth at 20 microm and processed for histochemistry. Sections of each specimen were stained with hematoxylin-eosin and other sections were subjected to histochemical NADPH-d detection. Results indicated the presence of NADPH reactivity within the pulps of both normal and carious teeth. In the normal teeth NADPH-d activity was detected in a small number of vascular endothelial cells and fibroblasts. The inflammatory response of the pulp from carious premolars was detected in connective tissue by the presence of an increased number of fibroblasts, angioblasts and collagen fibers. It was possible to determine the extent of odontoblast reactivity since the odontoblast layer was usually absent in these split-peel preparations. There were no obvious signs of stained pulpal nerve fibers. Overall NADPH-d staining was significantly more intense within inflamed pulp tissues compared to normal healthy samples (Mann-Whitney test, p<0.002). These results suggest that NADPH-d may be used as a marker of inflammatory activity in pulpitis and provide the basis for further studies aiming to clarify the possible functions of NO in human dental pulp in pathophysiological situations.
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PMID:Action of nitric oxide on healthy and inflamed human dental pulp tissue. 1833 11

Enzymes that reduce the aldehyde chemical grouping (i.e. H-C=O) to its corresponding alcohol are probably crucial in maintaining plant health during stress. Succinic semialdehyde (SSA) is a mitochondrially-generated intermediate in the metabolism of gamma-aminobutyrate (GABA), which accumulates in response to a variety of biotic and abiotic stresses. SSA can be reduced to gamma-hydroxybutyrate (GHB) under oxygen deficiency and high light conditions. Recent evidence indicates that distinct cytosolic and plastidial glyoxylate reductase isoforms from Arabidopsis (designated herein after as AtGR1 and AtGR2, respectively) catalyse the in vitro conversion of SSA to GHB, as well as glyoxylate to glycolate, via NADPH-dependent reactions. In the present report, the responses of GHB and related amino acids, as well as NADP(+) and NADPH, were monitored in leaves from Arabidopsis or tobacco plants subjected to various abiotic stresses (i.e. Arabidopsis during exposure to salinity, drought, submergence, cold, or heat; tobacco during exposure to, and recovery from, submergence). Time-course experiments revealed that GHB accumulated in both Arabidopsis and tobacco plants subjected to stress, and that this accumulation was generally accompanied by higher GABA and alanine levels, higher NADPH/NADP(+) ratio, and lower glutamate levels. Furthermore, the analysis of gene expression in Arabidopsis revealed that the relative abundance of GR1 (salinity, drought, submergence, cold, and heat) and GR2 (cold and heat) transcripts was enhanced by the stress tested. Thus, GHB accumulation in plants is a general response to abiotic stress and appears to be regulated by both biochemical and transcriptional processes.
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PMID:Gamma-hydroxybutyrate accumulation in Arabidopsis and tobacco plants is a general response to abiotic stress: putative regulation by redox balance and glyoxylate reductase isoforms. 1849 40

FRO2 (At1g01580) codes for an NADPH-dependent ferric reductase in plasma membranes of root epidermal cells with a demonstrated role in iron uptake by plants. Ferric reductase activity has been shown to be the rate-limiting step for iron uptake in strategy I plants like Arabidopsis and in rice, but it has been unclear whether FRO genes have other physiological functions. We hypothesized that FRO2 was involved in chilling stress tolerance because its expression was upregulated by treatment of plants with glycine betaine (GB), a chemical that prevents reactive oxygen species (ROS) signaling in chilling stress. This idea was confirmed by showing that the FRO2 null mutant frd1-1 failed to respond to GB in chilling assays either in relation to root growth recovery or inhibition of ROS accumulation. Measurements of ferric reductase activity in wild-type plants treated with GB before chilling showed no significant GB effect compared with controls. In addition, 35S-FRO2 transgenics with elevated mRNA levels did not have improved chilling tolerance. However, ferric reductase activity in wild-type plants or 35S-FRO2 transgenics pretreated with GB was several-fold higher after chilling compared with non-pretreated controls. These experiments identify a new physiological function for FRO2, i.e. blocking ROS accumulation during chilling. They also suggest that GB has a major effect on FRO2 activity posttranscriptionally in the cold.
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PMID:The FRO2 ferric reductase is required for glycine betaine's effect on chilling tolerance in Arabidopsis roots. 1972 47

We studied changes induced by cold on electron transfer pathways (linked to NADH or NADPH oxidation) in endoplasmic reticulum of rapeseed hypocotyls (Brassica napus L.) from a freezing-sensitive variety (ISL) and freezing-tolerant variety (Tradition). Plantlets were grown at 22 degrees C then submitted to a cold shock of 13 or 35 days at 4 degrees C. We measured the content in NADH, NADPH, NAD and NADP of the hypocotyls and the redox power was estimated by the reduced versus oxidized nucleotide ratio. The contents in cytochromes b (5) and P-450, electron acceptors of NADH and NADPH respectively, were determined by differential spectrophotometry. Finally, activity of both NADH-cytochrome b (5) reductase (E.C.1.6.2.2) and NADPH cytochrome P-450 reductase (E.C.1.6.2.4) was determined by reduction of exogenous cytochrome c. Results show that during cold shock, along with an increase of linolenic acid content, there was a general activation of the NADPH pathway which was observed more quickly in Tradition plantlets than in ISL ones. Due to transfer of electrons that can occur between NADPH reductase and cytochrome b (5), this could favor fatty acid desaturation in Tradition, explaining why linolenic acid accumulation was more pronounced in this variety. Besides, more cytochrome P-450 accumulated in ISL that could compete for electrons needed by the FAD3 desaturase, resulting in a relative slower enrichment in 18:3 fatty acid in these plantlets.
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PMID:Changes in electron transport pathways in endoplasmic reticulum of rapeseed in response to cold. 1866 70

Polyhydroxyalkanoates (PHAs) are highly reduced bacterial storage compounds that increase fitness in changing environments. We have previously shown that phaRBAC genes from the Antarctic bacterium Pseudomonas sp. 14-3 are located in a genomic island containing other genes probably related with its adaptability to cold environments. In this paper, Pseudomonas sp. 14-3 and its PHA synthase-minus mutant (phaC) were used to asses the effect of PHA accumulation on the adaptability to cold conditions. The phaC mutant was unable to grow at 10 degrees C and was more susceptible to freezing than its parent strain. PHA was necessary for the development of the oxidative stress response induced by cold treatment. Addition of reduced compounds cystine and gluthathione suppressed the cold sensitive phenotype of the phaC mutant. Cold shock produced very rapid degradation of PHA in the wild type strain. The NADH/NAD ratio and NADPH content, estimated by diamide sensitivity, decreased strongly in the mutant after cold shock while only minor changes were observed in the wild type. Accordingly, the level of lipid peroxidation in the mutant strain was 25-fold higher after temperature downshift. We propose that PHA metabolism modulates the availability of reducing equivalents, contributing to alleviate the oxidative stress produced by low temperature.
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PMID:Polyhydroxyalkanoates are essential for maintenance of redox state in the Antarctic bacterium Pseudomonas sp. 14-3 during low temperature adaptation. 1893 22

Cold-induced genes of highland barley (Hordeum vulgare L. var. nudum Hk. f.) were studied using suppression subtractive hybridization (SSH) technique. The cDNA from the materials treated with 4 degrees C was used as "tester", and that from the materials growing in green house (20+/-2 degrees C) as "driver". A subtractive library of highland barley including 640 cDNA clones was constructed in this study. Enzyme digestion of 32 clones chosen randomly from the library indicated that 87.5% of them contained inserts. The cDNA inserts of 16 clones were sequenced. Blast search analyses showed that these cDNAs were homologies to genes encoding the following proteins: metallothionein, protein kinase, ethylene signal transcription factor, bZIP transcription factor, zing finger transcription factor, ribulose-1,5-bisphosphate carboxylase, ribosomal protein, sodium: hydrogen antiporter, catalase, NADPH-cytochrome reductase, ascorbate peroxidase, DNA binding protein, and sugar transporter-like protein. These results indicated that the cDNA clones in the library were related to cold-induced genes, and suggested that the cold-tolerant mechanism of highland barley might be a complicated, interactive system involving multiple approaches and genes. Construction of subtractive cDNA library provided an advantage for further studies to isolate and clone cold-induced genes in highland barley.
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PMID:[Cold induced cDNA library construction of highland barley (Hordeum vulgare L. var. nudum Hk. f.) using suppression subtractive hybridization technology]. 1913 23

Thioredoxin and thioredoxin reductase from the psychrophilic eubacterium Pseudoalteromonas haloplanktis were obtained as recombinant His-tagged proteins (rPhTrx and rPhTrxR, respectively). rPhTrxR is organised as a homodimeric flavoenzyme, whereas rPhTrx is a small monomeric protein, both containing a functional disulfide bridge. However, three additional cysteines are present as free thiols in purified rPhTrxR. When individually tested in specific assays, rPhTrxR and rPhTrx display a full activity at low temperatures, an indispensable requirement for cold-adapted proteins. In particular, rPhTrxR catalyses the NADPH dependent reduction of DTNB and rPhTrx provokes the insulin precipitation in the presence of DTT. The analysis of the effect of temperature on these reactions indicates that rPhTrxR is more cold-adapted than rPhTrx, having a higher psychrophilicity. The combined activity of rPhTrxR and rPhTrx, tested in a reconstituted assay containing NADPH as electrons donor and human insulin as the thioredoxin substrate, demonstrates a direct functional interaction between the purified recombinant components of the thioredoxin system of P. haloplanktis. Furthermore, the NADPH-dependent reduction of rPhTrx catalysed by rPhTrxR is fully reversible and allows the determination of its redox potential, whose value is in the range of other bacterial and archaeal thioredoxins. The analysis of the thermostability of rPhTrxR points to its discrete heat resistance. However, rPhTrx is much more heat resistant, with a half inactivation time of about 4 h at 95 degrees C. This exceptional heat resistance for a psychrophilic protein is significantly decreased by the reduction of the disulfide bridge of rPhTrx. Functionality, thermodependence and thermostability of the P. haloplanktis thioredoxin system point to the relevance of this key mechanism for the preservation of the reduced state of cytoplasmic proteins even in a cold-adapted source.
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PMID:Differential cold-adaptation among protein components of the thioredoxin system in the psychrophilic eubacterium Pseudoalteromonas haloplanktis TAC 125. 1938 66

Adult Upis ceramboides do not survive freezing in the summer but tolerate freezing to -60 degrees C in midwinter. The accumulation of two cryoprotective polyols, sorbitol and threitol, is integral to the extraordinary cold-hardiness of this beetle. U. ceramboides are the only animals known to accumulate high concentrations of threitol; however, the biosynthetic pathway has not been studied. A series of (13)C-labeled compounds was employed to investigate this biosynthetic pathway using (13)C{(1)H} NMR spectroscopy. In vivo metabolism of (13)C-labeled glucose isotopomers demonstrates that C-3-C-6 of glucose become C-1-C-4 of threitol. This labeling pattern is expected for 4-carbon saccharides arising from the pentose phosphate pathway. In vitro experiments show that threitol is synthesized from erythrose 4-phosphate, a C(4) intermediate in the PPP. Erythrose 4-phosphate is epimerized and/or isomerized to threose 4-phosphate, which is subsequently reduced by a NADPH-dependent polyol dehydrogenase and dephosphorylated by a sugar phosphatase to form threitol. Threitol 4-phosphate appears to be the preferred substrate of the sugar phosphatase(s), promoting threitol synthesis over that of erythritol. In contrast, the NADPH-dependent polyol dehydrogenase exhibits broad substrate specificity. Efficient erythritol catabolism under conditions that promote threitol synthesis, coupled with preferential threitol biosynthesis, appear to be responsible for the accumulation of high concentrations of threitol (250 mm) without concomitant accumulation of erythritol.
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PMID:Cryoprotectant biosynthesis and the selective accumulation of threitol in the freeze-tolerant Alaskan beetle, Upis ceramboides. 1940 30

Plants have to contend with biotic stress, such as disease, mechanical wounding, and herbivory, as well as abiotic stress, such as heat, cold, and salinity. An early warning system for these threats would prevent or reduce the damage suffered by plants. Such a warning system should allow the signal to be rapidly generated and sent over long distances. The study of systemic signaling in plants has been a major scientific challenge. Reactive oxygen species (ROS) are among the systemic signals that have been proposed. Now, the exciting discovery that systemic ROS signaling is mediated by an NADPH (nicotinamide adenine dinucleotide phosphate, reduced form) oxidase opens the door to understanding the molecular mechanisms that initiate and propagate a rapid systemic signal.
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PMID:Sending ROS on a bullet train. 1979 66

The stress-associated protein SAP12 belongs to the stress-associated protein (SAP) family with 14 members in Arabidopsis thaliana. SAP12 contains two AN1 zinc fingers and was identified in diagonal 2D redox SDS-PAGE as a protein undergoing major redox-dependent conformational changes. Its transcript was strongly induced under cold and salt stress in a time-dependent manner similar to SAP10, with high levels after 6 h and decreasing levels after 24 and 48 h. The transcript regulation resembled those of the stress marker peroxiredoxin PrxIID at 24 and 48 h. Recombinant SAP12 protein showed redox-dependent changes in quaternary structure as visualized by altered electrophoretic mobility in non-reducing SDS polyacrylamide gel electrophoresis. The oxidized oligomer was reduced by high dithiothreitol concentrations, and also by E. coli thioredoxin TrxA with low dithiothreitol (DTT) concentrations or NADPH plus NADPH-dependent thioredoxin reductase. From Western blots, the SAP12 protein amount was estimated to be in the range of 0.5 ng mug(-1) leaf protein. SAP12 protein decreased under salt and cold stress. These data suggest a redox state-linked function of SAP12 in plant cells particularly under cold and salt stress.
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PMID:Redox-dependent regulation of the stress-induced zinc-finger protein SAP12 in Arabidopsis thaliana. 1982 20


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