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)

Threonine entry into brain is altered by diet-induced changes in concentrations of plasma amino acids, especially the small neutrals. To study this finding further, we compared effects of various amino acids (large and small neutrals, analogues, and transport models) on transport of threonine and phenylalanine across the blood-brain barrier. Threonine transport was saturable and was usually depressed more by natural large than small neutrals. Norvaline and 2-amino-n-butyrate (AABA) were stronger competitors than norleucine. 2-Aminobicyclo[2.2.1]heptane-2-carboxylate (BCH), a model in other preparations for the large neutral (L) system, and cysteine, a proposed model for the ASC system only in certain preparations, reduced threonine transport; 2-(methylamino)isobutyrate (MeAIB; a model for the A system for small neutrals) did not. Phenylalanine transport was most depressed by cold phenylalanine and other large neutrals; threonine and other small neutrals had little effect. Norleucine, but not AABA, was a strong competitor; BCH was more competitive than cysteine or MeAIB. Absence of sodium did not affect phenylalanine transport, but decreased threonine uptake by 25% (p less than 0.001). Our results with natural, analogue, and model amino acids, and especially with sodium, suggest that threonine, but not phenylalanine, may enter the brain partly by the sodium-dependent ASC system.
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PMID:Some characteristics of threonine transport across the blood-brain barrier of the rat. 313 88

Studies have been carried out on the development of a low-cost, high-quality infant food of low paste viscosity from rice, chickpea (Cicer arietinum) and cow's milk. In order to improve the overall quality of the product, chickpea was processed by different methods prior to its incorporation. A number of formulations was prepared by mixing 52% rice, 30% each, the processed chickpea sample, and 18% whole milk powder. These mixtures were processed by extrusion cooking or drum drying. In the case of the extrusion cooking method, from the nutritional and technological points of view, it was found advantageous to incorporate milk powder after cooking a mixture of rice and chickpea. The values of net protein ratio (NPR) of the products developed, whether processed by extrusion cooking or drum-drying methods, were statistically equal, and not significantly different from those of casein. Supplementing the product with methionine and threonine showed no effect in improving the NPR value, suggesting that these amino acids were not limiting. There were slight differences in the digestibilities of proteins in the products developed and all were lower than that of casein. Depending on the processing method, differences were observed in paste viscosities of the products. After partial hydrolysis of the products with pounds amylase, both the cold and hot paste viscosities were greatly reduced and were comparable with those of whole milk powder. From the results herein reported, it can be concluded that the drum-dried product prepared using rice:chickpea (carbonate presoaked):milk (52:30:18) is the best of all the products developed. Its amino acid composition compares favorably with that of the milk proteins.
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PMID:Studies on the development of infant foods from plant protein sources. Part III. Preparation, processing and properties of various products developed. 384 32

The per locus plays a central role in the organization and function of the Drosophila biological clock. The gene has been mapped to a 7-kb DNA segment by physically locating the breakpoints of several chromosomal rearrangements that disrupt per function. This DNA contains a single transcription unit which produces a 4.5-kb poly(A)+ RNA. No oscillation in the synthesis of this transcript is detected when per expression is followed over a 24-hour cycle of light and dark. When wild-type DNA containing only this transcription unit is transferred to the genome of a per0 (arrhythmic) fly by P-element-mediated transformation, the 4.5-kb RNA is produced and rhythmic behavior is restored with high penetrance of the rhythmic phenotype. This transforming DNA will also complement chromosomal deletions that include the per locus and adjoining transcription units, indicating that only one gene in this chromosomal interval plays a measureable role in the production of circadian rhythms. Transformed flies having rhythms with longer than wild-type periodicity underproduce the 4.5-kb RNA. We suggest that the periodicity of circadian rhythms in Drosophila is determined by the level of expression of a per locus protein encoded by the 4.5-kb transcript. We have found DNA homologous to the per locus in several species of vertebrates. DNA exhibiting very high homology to a portion of the per locus has been cloned from the mouse and the DNA sequence of the conserved segment has been determined. Mouse and fly DNAs both appear to code for long protein segments composed exclusively of alternating threonine and glycine or serine and glycine residues.
Cold Spring Harb Symp Quant Biol 1985
PMID:A biological clock in Drosophila. 386 9

Several mutants of Salmonella typhimurium LT-2, isolated as auxotrophs for vitamin B(6), grew without the added vitamin when supplied with either isoleucine, alpha-ketobutyrate, or alpha-keto-beta-methylvalerate, but not with threonine or with other alpha-keto acids. When grown on minimal medium supplemented with isoleucine, these mutants synthesized vitamin B(6) in amounts comparable to wild-type cells; they thus appeared to contain a modified l-threonine dehydratase and to belong to genotype ilvA (threonine dehydratase) instead of pdx (pyridoxine). Direct assays confirmed this hypothesis. Wild-type cells (toluene-treated) showed approximately the same threonine dehydratase activity whether grown in the presence or absence of added pyridoxal-P; mutant cells approached the activity of wild-type cells only when they were grown with added vitamin B(6) and were assayed in the presence of pyridoxal-P. In cell-free extracts, the threonine dehydratase from mutant cells was cold labile and more labile to oxidative inactivation than the wild-type enzyme; furthermore, activation of the mutant apoenzyme required a 10- to 20-fold higher concentration of pyridoxal-P than was required for the wild-type apoenzyme. These results show that cultures which appear auxotrophic for a given vitamin may synthesize that vitamin in normal amounts, the exogenous requirement arising from impaired binding of the vitamin-derived coenzyme to a genetically altered apoenzyme dependent on that coenzyme. Inadequate nutritional data to support the genetic findings can lead to erroneous genotype classification for such mutants.
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PMID:Salmonella typhimurium mutants with alternate requirements for vitamin B 6 or isoleucine. 494 63

The objective of this study was to evaluate by relatively simple metabolic tests the usefulness of buffers and energy sources commonly used in Legionella growth media. Legionella pneumophila serogroups 1 to 6, Legionella micdadei, and Legionella bozemanii were grown in an enriched charcoal-yeast extract diphasic medium. The cells were washed thrice, suspended in various buffers (pH 6.9) with 1 or 5 mM MgSO4, and used immediately or after controlled-rate cryopreservation. CO2 produced and C incorporated into the cold trichloracetic acid-insoluble fractions from 14C-labeled substrates were determine. Potassium phosphate buffer (0.02 M) was as satisfactory as organic buffers for glutamate metabolism, but the addition of KCl or NaCl reduced activity. Metabolic activity for glutamate was not lost upon cryopreservation, and cryopreserved cells were used to test the utilization of other single or paired substrates. Rates of activity for serine, glutamate, threonine, and pyruvate, in this descending order, were high, and those for alpha-ketoglutarate, succinate, and gamma-aminobutyrate were low. Although glutamine was not used as rapidly as glutamate, when added to glutamate it was preferentially metabolized, possibly because of more rapid transport. When glutamate and serine were combined, glutamate furnished more C for CO2 and less for incorporation, whereas the reverse was true of serine. In conclusion, glutamate as an energy source may in some cases spare other amino acids for synthesis. alpha-Ketoglutarate, a common constituent of Legionella media, may reduce oxygen toxicity but is probably not a chief energy source.
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PMID:Substrate utilization by Legionella cells after cryopreservation in phosphate buffer. 614 14

1. Sperm nuclei were isolated and purified from boar semen by a procedure involving differential solubilization of sperm tail and acellular materials by brief exposure to reducing reagent in the presence of cationic detergent, and sedimentation through 60% sucrose. The weight ratio of DNA:RNA: total protein: protamine in this preparation was 1.00: 0.02: 1.05: 0.75, and the molar ratio of phosphorus to arginine was 1.12. 2. Boar protamine was extracted with cold acid from ethanol precipitate of reduced and carboxymethylated nuclei in 6 M guanidine hydrochloride and purified by ion-exchange chromatography on CM-cellulose. The molecular weight of the protamine was estimated to be 6600 by the gel filtration method. The protamine consisted of a single amino terminus alanine and either half-cystine or arginine as carboxy terminus, and was composed of Thr, Ser3, Pro2, Ala2, Val2, Ile, His, Half-cystine9-10 and Arg26 . 3. Chymotryptic digestion gave rise to a single amino-terminal peptide, Ala-Arg-Tyr, and two carboxy-terminal peptides, Thr-Val-Ile-Arg-Cys-Arg2-Cys and Thr-Val-Ile-Arg-Cys-Arg2, which confirmed the heterogeneity of the protamine at the carboxy-terminal end.
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PMID:Isolation and characterization of nuclear basic protein (protamine) from boar spermatozoa. 713 87

Seven blood group H active glycopeptides were isolated from the defatted seeds of Euonymus Sieboldiana by a procedure that included extraction with cold phosphate-buffered saline, fractionation with ammonium sulfate, chromatography with CM- and DEAE Sepharose CL 6B, and gel filtration on Sepharose 4B and Sephacryl S-200. Each glycopeptide, except three macromolecular ones, eluted as a single symmetrical peak from the Sephacryl S-200 chromatography. On the basis of their elution from a column that had been calibrated with FITC-dextrans as molecular weight markers, these glycopeptides had molecular weights of approximately 110,000, 15,000 and 8,000. All isolated H active glycopeptides inhibited eel anti-H reagent at concentrations of 1 to 63 microgram/ml and exhibited a single precipitation band against the eel reagent on immunodiffusion. Furthermore, all of them contained galactose and arabinose as major sugars, with fucose, rhamnose, mannose, glucose and glucosamine as minor sugars. Amino acid analysis of the four H active glycopeptides retarded by the Sepharose 4B column revealed the presence of hydroxyproline together with large amounts of threonine and serine. However, the three excluded macromolecular H active glycopeptides contained both threonine and serine, but no hydroxyproline.
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PMID:Purification, composition and immunochemical properties of arabinogalactan-protein H active glycopeptides from Euonymus sieboldiana seeds. 733 33

The nucleotide sequences of the neuraminidase (NA) genes of the A/Leningrad/134/57 (H2N2) wild-type (Len/wt) virus as well as two of its live attenuated, cold-adapted (ca) variants, A/Leningrad/134/17/57 (Len/17) and A/Leningrad/134/47/57 (Len/47), were determined. In comparison with Len/wt, one nucleotide change (C-225 to A) was found in the NA gene of Len/17. This change codes for a Thr-to-Asn substitution at position 69 of NA. The NA gene of the more attenuated Len/47 ca virus has one silent (T-814 to C) and two coding nucleotide substitutions, C-78 to T (Ala-20 to Val) and C-225 to A (Thr-69 to Asn). These sequence data were used to design a PCR-restriction technique to determine the origin of the NA gene in candidate live, attenuated vaccine reassortants made by reassorting these ca strains with current field viruses.
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PMID:Nucleotide sequences of the neuraminidase genes of influenza A/Leningrad/134/57 (H2N2) virus and two of its live, attenuated, cold-adapted variants. 748 95

Eukaryotic Y-box proteins are reported to interact with a wide variety of nucleic acid structures to act as transcription factors and mRNA masking proteins. The modular structure of Y-box proteins includes a highly conserved N-terminal cold-shock domain (CSD, equivalent to the bacterial cold-shock proteins) plus four basic C-terminal domains containing arginine clusters and aromatic residues. In addition, the basic domains are separated by acidic regions which contain several potential sites for serine/threonine phosphorylation. The interaction of Y-box proteins, isolated from Xenopus oocytes (FRGY2 type), with RNA molecules has been studied by UV crosslinking and protein fragmentation. We have identified two distinct binding activities. The CSD interacts preferentially with the polypurines poly(A,G) and poly(G) but not poly(A), this activity being sensitive to 5 mM MgCl2 but not to 5 mM spermidine. In the presence of 1 mM MgCl2 or 1 mM spermidine, the basic domains interact preferentially with poly(C,U), this activity being sensitive to 0.5 M NaCl. Binding of the basic domains is also sensitive to low concentrations of heparin. The basic domains can be crosslinked individually to labelled RNA. These results are discussed with reference to the various specificities noted in the binding of Y-box proteins to RNA and DNA.
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PMID:Binding of Y-box proteins to RNA: involvement of different protein domains. 753 Aug 42

The Escherichia coli chemoreceptor Tsr mediates an attractant response to serine. We substituted Cys for Thr-156, one of the residues involved in serine sensing. The mutant receptor Tsr-T156C retained serine- and repellent-sensing abilities. However, it lost serine-sensing ability when it was treated in vivo with sulfhydryl-modifying reagents such as N-ethylmaleimide (NEM). Serine protected Tsr-T156C from these reagents. We showed that [3H]NEM bound to Tsr-T156C and that binding decreased in the presence of serine. By pretreating cells with serine and cold NEM, Tsr-T156C was selectively labeled with radioactive NEM. These results are consistent with the location of Thr-156 in the serine-binding site. Chemical modification of the Tsr ligand-binding site provides a basis for simple purification and should assist further in vivo and in vitro investigations of this chemoreceptor protein.
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PMID:In vivo sulfhydryl modification of the ligand-binding site of Tsr, the Escherichia coli serine chemoreceptor. 772 14


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