Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0085593 (chills)
 4,268 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neocarzinostatin (NCZ), an acidic polypeptide antibiotic, was given to 47 patients with cancer and leukemia, and tolerance to two schedules, a single dose given as a 2 hour infusion and a continuous infusion over 5 days was investigated. Immediate reactions, including fever, chills, rigor, hypertension and mental confusion, were dose-limiting for the 2 hour infusion schedule, occurring at 3000 U/m2 and higher. Continuous administration for 5 days eliminated the immediate reactions and then hematological toxicity--often prolonged leukopenia and thrombocytopenia--became dose-limiting. Other toxicities of NCZ at both dose schedules included anemia, fever and chills, anorexia, nausea and vomiting, hepatic dysfunction, azotemia, hypophosphatemia, aminoaciduria, stomatitis, phlebitis and/or cellulitis at the venous infusion site and pruritus. Patients with solid tumors who had received little or no prior chemotherapy and had good bone marrow reserve tolerated up to 6000 U/m2/24 hours X 5 days. One patient with previously treated acute myelocytic leukemia was induced into a good partial remission lasting 10 weeks.
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PMID:Phase I study with neocarzinostatin: tolerance to two hour infusion and continuous infusion. 15 43

Previous reviews of the effects of temperature on in vivo photosynthesis have mainly concerned the effects of temperature on light saturated rates. The quantum yield of photosynthesis (phi), as a measure of light limited photosynthesis, has generally been regarded as temperature insensitive. At temperatures close to the minima and maxima at which plants can sustain photosynthetic CO2 assimilation, light may damage the photosynthetic apparatus, an effect termed photoinhibition. A constant feature of photoinhibition is a reduction in phi. In maize, chilling-dependent photoinhibition reduces both phi and the light saturated rate of CO2 assimilation (Asat) and of O2 evolution. Analysis of recovery of CO2 uptake in these leaves suggests that whilst Asat recovers in a few hours, phi may not be fully restored for days. Examination of mature crop canopies shows that only a small proportion of the leaves are likely to become light saturated and then only for part of the day. The relative significance of temperature-induced changes in Asat and phi have also been tested in canopy models of maize crop photosynthesis. These suggest that whilst changes in either parameter will have similar effects on total canopy photosynthesis on the sunniest days of the year, for an average summer's day changes in phi will be of far greater importance. Consideration is therefore given to the factors associated with thylakoid membranes that may determine temperature-induced decreases in phi. Chilling of maize leaves under high light levels reduces the quantum yield of PSII and whole chain electron transport in concert with a decrease in the capacity of isolated thylakoids to bind atrazine, which is indicative of a loss or damage to the QB protein. Besides such classical symptoms of photoinhibition of PSII, chilling also induces the accumulation of a 31 kDa polypeptide in the thylakoids of maize leaves. This polypeptide fractionates with the light-harvesting chlorophyll a/b protein complex (LHCII) and has been tentatively identified as an unprocessed precursor of CP29 since it binds chlorophyll and is immunologically related to CP29. Accumulation of the 31 kDa polypeptide is associated with a modification in the energetics of LHCII, which may result in a decrease in excitation energy from LHCII to PSII and contribute to a decrease in phi. Examination is also made of how stress-induced modifications of interactions between PSII complexes, functioning of the cyt b6/f complex, the permeability of the thylakoid membrane to protons and the activity of the coupling factor may contribute to decreases in phi.
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PMID:Photosynthesis and temperature, with particular reference to effects on quantum yield. 307 64

Diurnal change in the temperature below or above 12.5 degrees C hastens the degreening of citrus peel and elicits the phytohormone ethylene production in citrus fruit. Ethylene triggers the degradation of chlorophyll and synthesis of carotenoids in citrus peel. To investigate if ethylene is required for the degreening of citrus peel elicited by low temperatures, we studied the chilling-regulated gene expression of ACC synthase, one of the key enzymes catalyzing ethylene biosynthesis. We isolated and characterized a chilling-inducible 1-aminocyclopropane-1-carboxylate synthase (ACC synthase) gene, CS-ACS1, and a chilling-repressible gene, CS-ACS2, from citrus peel. The CS-ACS1 transcript 1.7 kb in length encodes a polypeptide of 483 amino acids (Mr 54,115, pI 6.63), whereas the CS-ACS2 transcript of 1.8 kb encodes a polypeptide of 477 amino acids (Mr 53,291, pI 6.72). Both genes showed a rapid but transient induction (within 2.4 h) of transcripts upon rewarming after the chilling (4 degrees C) treatment. After 24 h of incubation at room temperature, CS-ACS1 mRNA diminished to an undetectable level, whereas the CS-ACS2 mRNA regained its basal level of expression attained prior to the chilling treatment. Chilling-induced ethylene production and ACC accumulation were also observed upon rewarming. Both genes were also induced by the wound stress (excision). The protein synthesis inhibitor cycloheximide super-enhances the accumulation of both ACS transcripts at room temperature. Molecular analysis of the 3.3 kb genomic DNA of CS-ACS1 revealed that this gene consists of three introns and four exons. The intron 3 is exceptionally large ( 1.2 kb) and shares significant homology with mitochondrial DNA, supporting the intron-late theory.
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PMID:Identification of two chilling-regulated 1-aminocyclopropane-1-carboxylate synthase genes from citrus (Citrus sinensis Osbeck) fruit. 1064 19

The effects of reductions in growth temperature on the development of thylakoids of maize (Zea mays var LG11) leaves are examined. Thylakoids isolated from mesophyll cells of leaves grown at 17 degrees and 14 degrees C, compared with 25 degrees C, exhibited a decreased accumulation of many polypeptides, which was accompanied by a loss of activity of photosystems (PS) I and II. Probing the polypeptide profiles with a range of antibodies specific for thylakoid proteins demonstrated that a number of polypeptides encoded by the chloroplast genome failed to accumulate at low temperatures. Although thylakoid protein synthesis was reduced severely at 14 degrees C compared with 25 degrees C, major synthesis of both chloroplast and nuclear encoded polypeptides was detected. It is suggested that the lack of accumulation of some thylakoid proteins at low temperatures may be due to an inability to stabilize the proteins in the membranes. A number of thylakoid polypeptides were found to appear as the growth temperature was decreased. Analyses of pigments and polypeptides demonstrated that decreases in the photosystem reaction center core complexes occur relative to the light harvesting complex associated with PS II at reduced growth temperatures. Differential effects on the development of PSI and PSII were also observed, with PSII activity being preferentially reduced. Reductions in PSII content and activity occurred in parallel with decreases in the quantum yield and light-saturated rate of CO(2) assimilation. Fractionation of thylakoid pigment-protein complexes showed that the ratio of monomeric:oligomeric form of the light harvesting complex associated with PSII increased at low growth temperature, which is consistent with a chill-induced modification of thylakoid organization. Many, but not all, of the characteristic changes in thylakoid protein metabolism, which were observed when leaves were grown at low temperatures in controlled environments, were identified in leaves of a field maize crop during the early growing season when low temperatures were experienced by the crop. Chill-induced perturbations of thylakoid development can occur in the field in temperate regions and may have implications for the photosynthetic productivity of the crop.
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PMID:Modifications to Thylakoid Composition during Development of Maize Leaves at Low Growth Temperatures. 1666 49

StCKP1 (Solanum tuberosum cytokinin riboside phosphorylase) catalyses the interconversion of the N9-riboside form of the plant hormone CK (cytokinin), a subset of purines, with its most active free base form. StCKP1 prefers CK to unsubstituted aminopurines. The protein was discovered as a CK-binding activity in extracts of tuberizing potato stolon tips, from which it was isolated by affinity chromatography. The N-terminal amino acid sequence matched the translation product of a set of ESTs, enabling a complete mRNA sequence to be obtained by RACE-PCR. The predicted polypeptide includes a cleavable signal peptide and motifs for purine nucleoside phosphorylase activity. The expressed protein was assayed for purine nucleoside phosphorylase activity against CKs and adenine/adenosine. Isopentenyladenine, trans-zeatin, dihydrozeatin and adenine were converted into ribosides in the presence of ribose 1-phosphate. In the opposite direction, isopentenyladenosine, trans-zeatin riboside, dihydrozeatin riboside and adenosine were converted into their free bases in the presence of Pi. StCKP1 had no detectable ribohydrolase activity. Evidence is presented that StCKP1 is active in tubers as a negative regulator of CKs, prolonging endodormancy by a chill-reversible mechanism.
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PMID:A purine nucleoside phosphorylase in Solanum tuberosum L. (potato) with specificity for cytokinins contributes to the duration of tuber endodormancy. 2432 49