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)

Alkaline phosphatase (AP) from Atlantic cod (Gadus morhua) is a zinc and magnesium containing homodimer that requires the oligomeric state for activity. Its kinetic properties are indicative of cold-adaptation. Here, the effect of urea on the structural stability was studied in order to correlate the activity with metal content, the microenvironment around tryptophan residues, and events at the subunit interface. At the lowest concentrations of urea, the first detected alteration in properties was an increase in the activity of the enzyme. This was followed by inactivation, and the release of half of the zinc content when the amount of urea reached levels of 2 M. Intrinsic tryptophan fluorescence and circular dichroism ellipticity changed in the range 2.5 to 8 M urea, signaling dimer dissociation, followed by one major monomer unfolding transition at 6-8 M urea as indicated by ANS fluorescence and KI fluorescence quenching. Gibbs free energy was estimated by the linear extrapolation method using a three-state model as 8.6 kcal/mol for dimer stability and 11.6 kcal/mol for monomer unfolding giving a total of 31.8 kcal/mol. Dimer association had a very small ionic contribution. Dimers were stable in relatively high concentration of urea, whereas the immediate vicinity around the active site was vulnerable to low concentrations of urea. Thus, inactivation did not coincide with dimer dissociation, suggesting that the active site is the most dynamic part of the molecule and closest related to cold-adaptation of its enzymatic activity.
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PMID:Reversible inactivation of alkaline phosphatase from Atlantic cod (Gadus morhua) in urea. 1644 5

Effects of molybdenum (Mo) on antioxidative defense system and membrane lipid peroxidation in leaves of winter wheat (Triticum aestivum H. var. Huamai 8) were investigated under low temperature stress. Results of experiments indicate that Mo application in winter wheat induced a dramatic decrease in electrolyte leakage and malondialdehyde content under low temperature stress. The activities of antioxidative enzymes such as superoxide dismutase (SOD, EC 1.15.1.1), peroxidase (POX, EC 1.11.1.7) and catalase (CAT, EC 1.11.1.6) were increased by Mo application and the extents of increase at low temperature were higher than those at normal temperature. Mo application also caused a significant increase in the ascorbic acid (AsA) and proline contents both at normal and low temperature and following the low temperature stress the increases in ascorbic acid and proline contents in Mo-treated winter wheat were higher. There was no significant difference in carotenoid (CAR) content between with and without Mo treatment under normal temperature, while there was a significant increase in Mo treatment under low temperature stress. It could be speculated that Mo application enhanced cold resistance by increasing the capacity to scavenge active oxygen species and alleviating membrane damage in winter wheat under low temperature stress.
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PMID:Effects of molybdenum on antioxidative defense system and membrane lipid peroxidation in winter wheat under low temperature stress. 1662 16

Methanolic extract of Musa sapientum var. Paradisiaca (MSE, 100 mg/kg) was studied for its antiulcer and mucosal defensive factors in normal and non-insulin dependent diabetes mellitus (NIDDM) rats. NIDDM was induced by administering streptozotocin (STZ, 70 mg/kg, ip) to 5 days old rat pups. The animals showing blood glucose level >140mg/dL after 12 weeks of STZ administration were considered as NIDDM positive. Effects of MSE were compared with known ulcer protective drug, sucralfate (SFT, 500 mg/kg) and anti-diabetic drug glibenclamide (GLC, 0.6 mg/kg) when administered orally, once daily for 6 days against gastric ulcers (GU) induced by cold-restraint stress (CRS) and ethanol and subsequent changes in gastric mucosal glycoproteins, cell proliferation, free radicals (lipid peroxidation and nitric oxide) and anti-oxidants enzymes (super oxide dismutase and catalase) and glutathione (GSH) levels. MSE showed better ulcer protective effect in NIDDM rats compared with SFT and GLC in CRS-induced GU. NIDDM caused a significant decrease in gastric mucosal glycoprotein level without having any effect on cell proliferation. However, all the test drugs reversed the decrease in glycoprotein level in NIDDM rats, but cell proliferation was enhanced in case of MSE alone. Both CRS or NIDDM as such enhanced gastric mucosal LPO, NO and SOD, but decreased CAT levels while CRS plus NIDDM rats caused further increase in LPO and NO level without causing any further changes in SOD and CAT level. MSE pretreatment showed reversal in the levels of all the above parameters better than GLC. Ethanol caused a decrease in glutathione level which was further reduced in NIDDM-ethanol rats. MSE reversed the above changes significantly in both normal as well as in NIDDM rats, while GLC reversed it only in NIDDM rats. However, SFT was ineffective in reversing the changes induced by CRS or ethanol or when given in NIDDM-CRS or NIDDM-ethanol rats. The results indicated that the ulcer protective effect of MSE could be due to its predominant effect on mucosal glycoprotein, cell proliferation, free radicals and antioxidant systems.
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PMID:Effect of plantain banana on gastric ulceration in NIDDM rats: role of gastric mucosal glycoproteins, cell proliferation, antioxidants and free radicals. 1662 71

Soybeans are a rich source of protein and a key feed ingredient in livestock production, but lack sufficient levels of cysteine and methionine to meet the nutritional demands of swine or poultry as feed components. Although engineering the sulfur assimilatory pathway could lead to increased sulfur-containing amino acid content, little is known about this pathway in legumes. Here, we describe the cloning and characterization of soybean ATP sulfurylase (ATPS), which acts as the metabolic entry point into the sulfur assimilation pathway. Analysis of the ATPS clone isolated from a soybean seedling cDNA library revealed an open-reading frame, encoding a 52 kDa polypeptide with an N-terminal chloroplast/plastid transit peptide, which was related to the enzymes from Arabidopsis, potato, human, and yeast. Soybean ATP sulfurylase was expressed in Escherichia coli and purified to apparent homogeneity. Based on gel-filtration chromatography, the enzyme functions as a 100 kDa homodimer. Analysis of genomic DNA by Southern blotting revealed that multiple genes encode ATP sulfurylase in soybean. Analysis of the transcript profiles retrieved from a soybean EST database indicated that ATP sulfurylase mRNA was most abundant in root tissue. Cold treatment induced mRNA accumulation and enhanced the specific activity of ATP sulfurylase in root tissue. Northern blot analysis indicated a decline in the ATP sulfurylase transcript levels during seed development. Likewise, ATP sulfurylase specific activity also declined in the later stages of seed development. Increasing the expression levels of this key enzyme during soybean seed development could lead to an increase in the availability of sulfur amino acids, thereby enhancing the nutritional value of the crop.
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PMID:Soybean ATP sulfurylase, a homodimeric enzyme involved in sulfur assimilation, is abundantly expressed in roots and induced by cold treatment. 1668 99

The study on the changes of physiological and biochemical properties of grafted eggplant seedling roots under low temperature stress and the relationships between these changes and cold tolerance showed that at the initial stage of treating with 10 degrees C (daytime) /3 degrees C (night), eggplant seedling roots were most impressible to low temperature, with the MDA content, chilling injury index, POD activity, proline content and soluble protein content increased significantly, and root respiration rate, SOD activity and CAT activity decreased rapidly. With the extending of low temperature stress, root respiration rate and osmotic adjustment reduced continually, while chilling injury index increased. After 3 days recovery, the respiration rate, osmotic adjustment and SOD activity were increased. Among the test materials, T2 (with Hiranasu as rootstock) had the best recovery capability, followed by T1 (with Taibyo as rootstock) and CK (Jinong 2000). Grafting with stronger cold tolerance rootstock could improve eggplant root activity, and thus, its cold resistance markedly.
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PMID:[Responses of grafted eggplant seedling roots to low temperature stress]. 1672 29

We have investigated the glycosylation, disulfide bonding, and subunit structure of mouse TRPM8. To do this, amino-terminal c-myc or hemagglutinin epitope-tagged proteins were incorporated and expressed in Chinese hamster ovary cells. These modifications had no obvious effects on channel function in intracellular calcium imaging assays upon application of agonists, icilin or menthol, and cold temperatures. Unmodified TRPM8 migrates with an apparent mass of 129 kDa and can be glycosylated in Chinese hamster ovary cells to give glycoproteins with apparent masses of 136 and 147 kDa. We identified two potential N-linked glycosylation sites in TRPM8 (Asn-821 and Asn-934) and mutated them to show that only the site in the putative pore region at position 934 is modified and that glycosylation of this site is not absolutely necessary for cell surface expression or responsiveness to icilin, menthol, and cool temperatures. Enzymatic cleavage of the carbohydrate chains indicated that they are complex carbohydrate. The glycosylation site is flanked in the pore by two cysteine residues that we mutated, to prove that they are involved in a conserved double cysteine motif, which is essential for channel function. Mutation of either of these cysteines abolishes function and forces the formation of a non-functional complex of the size of a homodimer. The double cysteine mutant is also non-functional. Finally, we showed in Perfluoro-octanoic acid-polyacrylamide gels that TRPM8 can form a tetramer (in addition to dimer and trimer forms), consistent with current thinking that functional TRP ion channels are tetrameric.
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PMID:The cold and menthol receptor TRPM8 contains a functionally important double cysteine motif. 1701 41

Polar organisms should have mechanisms to survive the extremely cold environment. Four genes encoding cold-shock proteins, which are small, cold-induced bacterial proteins, have been cloned from the Antarctic bacterium Streptomyces sp. AA8321. Since the specific functions of any polar bacterial or Streptomyces cold-shock proteins have not yet been determined, we examined the role of cold-shock protein A from Streptomyces sp. AA8321 (CspA(St)). Gel filtration chromatography showed that purified CspA(St) exists as a homodimer under physiological conditions, and gel shift assays showed that it binds to single-stranded, but not double-stranded, DNA. Overexpression of CspA(St) in Escherichia coli severely impaired the ability of the host cells to form colonies, and the cells developed an elongated morphology. Incorporation of a deoxynucleoside analogue, 5-bromo-2'-deoxyuridine, into newly synthesized DNA was also drastically diminished in CspA(St)-overexpressing cells. These results suggest that CspA(St) play a role in inhibition of DNA replication during cold-adaptation.
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PMID:Characterization of cold-shock protein A of Antarctic Streptomyces sp. AA8321. 1720 95

Glutathione S-transferase from the digestive gland of the cold-adapted marine bivalve Icelandic scallop was purified to apparent homogeneity by single GSTrap chromatography. The enzyme appeared to be a homodimer with subunit M(r) 22,000 having an optimum catalytic activity at pH 6.5-7. Enzymatic analysis of scallop GST using the substrates 1-chloro-2,4-dinitrobenzene (CDNB) and glutathione resulted in apparent values for K(m)(GST) and K(m)(CDNB) of 0.3 mM and 0.4 mM, respectively. The scallop GST lost activity faster than porcine GST when exposed to increased temperatures, but both enzymes needed 10 min incubation at 60 degrees C for complete inactivation. A partial coding sequence was identified in cDNA synthesised from digestive gland mRNA. Comparison to known sequences indicates that the gene product is a glutathione S-transferase, and the predicted Icelandic scallop GST protein scores 40% sequence identity and 60% sequence similarity to mu-class proteins.
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PMID:Glutathione S-transferase from the Icelandic scallop (Chlamys islandica): isolation and partial characterization. 1720 21

The aim of the present work was to determine the activities of selected antioxidant enzymes (SOD, Se-GPX, CAT) in two species of bivalves, Scapharca inaequivalvis and Tapes philippinarum, from two sites of the lagoon of Venice that are characterized by different pO(2) (Marghera and Chioggia). The specimens were collected at four times during a 1-year period. In the two species studied, enzyme activities were found to be present in both digestive glands and gills, but with some species-specific differences that may also represent a different adaptation to seasonal variations. The presence of high SOD activities in the gills of both species may be related to their physiological role in respiration. Scapharca inaequivalvis is less sensitive than T. philippinarum to environmental changes, perhaps due to the presence of hemoglobins in this species. Moreover, in the digestive gland of T. philippinarum we found a significant negative correlation between the activities of SOD and GPX that may indicate the presence of oxidative stress. Some correlations between temperature/dissolved oxygen and antioxidant enzyme activity were present in specimens sampled in Marghera. Only GPX adequately responded to changes in dissolved oxygen and temperature, while the decrease in the activity of SOD and CAT in winter may be directly responsible for an enhanced susceptibility of mussels to oxidative stress during this period. We can conclude that the observed differences between Chioggia and Marghera are due to different concentrations of dissolved oxygen. Marghera is an appropriate location to study seasonal variations in water temperature. In fact, in this site, the differences between hot and cold months are quite evident.
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PMID:Antioxidant responses to variations in dissolved oxygen of Scapharca inaequivalvis and Tapes philippinarum, two bivalve species from the lagoon of Venice. 1736 22

Ischemia/reperfusion injury (IRI) remains an important problem in clinical transplantation. Following ischemia, phosphatidylserine (PS) translocates to surfaces of endothelial cells (ECs) and promotes the early attachment of leukocytes/platelets, impairing microvascular blood flow. Diannexin, a 73 KD homodimer of human annexin V, binds to PS, prevents attachment of leukocytes/platelets to EC, and maintains sinusoidal blood flow. This study analyzes whether Diannexin treatment can prevent cold IRI in liver transplantation. Rat livers were stored at 4 degrees C in UW solution for 24 h, and then transplanted orthotopically (OLT) into syngeneic recipients. Diannexin (200 microg/kg) was infused into: (i) donor livers after recovering and before reperfusion, (ii) OLT recipients at reperfusion and day +2. Controls consisted of untreated OLTs. Both Diannexin regimens increased OLT survival from 40% to 100%, depressed sALT levels, and decreased hepatic histological injury. Diannexin treatment decreased TNF-alpha, IL-1beta, IP-10 expression, diminished expression of P-selectin, endothelial ICAM-1, and attenuated OLT infiltration by macrophages, CD4 cells and PMNs. Diannexin increased expression of HO-1/Bcl-2/Bcl-xl, and reduced Caspase-3/TUNEL+ apoptotic cells. Thus, by modulating leukocyte/platelet trafficking and EC activation in OLTs, Diannexin suppressed vascular inflammatory responses and decreased apoptosis. Diannexin deserves further exploration as a novel agent to attenuate IRI, and thereby improve OLT function/increase organ donor pool.
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PMID:Diannexin, a novel annexin V homodimer, protects rat liver transplants against cold ischemia-reperfusion injury. 1786 64


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