Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fourteen di- and tripeptide analogues of MIF, Pro-Leu-Gly-NH2, have been synthesized and assayed for inhibition of oxotremorine-induced tremor. Replacement of Pro by HCO-Pro or cyclopentanecarboxylic acid gave inactive analogues, while some peptides of the general structure less than Glu-Leu-Gly-NR1R2 were highly active. Thus, R1 = C3H8 and R2 = H gave 4 times the activity of MIF, R1 = I-C3H8 and R2 = H gave 13 times the activity of MIF, and R1 = R2 = CH3 gave 29 times the activity of MIF. cyclo(-Pro-Leu-), Pro-Lys-Gly-NH2, and Pro-Arg-Gly-NH2 had no activity. Apparently, small modifications in the structure of MIF can yield highly active analogues with potential clinical value, e.g., in the treatment of Parkinson's disease or mental depression.
 ...
PMID:Tripeptide analogues of melanocyte-stimulating hormone release-inhibiting hormone (Pro-Leu-Gly-NH2) as inhibitors of oxotremorine-induced tremor. 4 28

A hapten-specific unresponsive state was induced in vitro by the incubation of normal murine spleen cells with highly conjugated dinitrophenylated bovine gamma-globulin (DNP-BGG) or a dinitrophenylated copolymer of D-glutamic acid and D-lysine (DNP-D-GL) for 24 hr. After this incubation period spleen cells were washed and cultured for 4 days with the thymic-independent antigen dinitrophenylated polyacrylamide beads (DNP-PAA) or the thymic-dependent antigen trinitrophenylated burro the erythrocytes (TNP-BRBC). Preincubation with either DNP-BGG or DNP-D-GL led to a specific depression of the in vitro anti-hapten plaque-forming cell response. The degree of depression was dependent upon the concentration of the tolerogen and the duration of preincubation. The response to DNP-PAA or TNP-PAA beads was depressed to a greater degree than was the response to TNP-BRBC. The cellular basis of the immunologic unresponsiveness induced by DNP-BGG was attributable to an inhibition of B cell function whereas the unresponsive state induced with DNP-D-GL was due to both a specific inhibition of B cell function and the activation of antigen-specific suppressor T cells.
 ...
PMID:Cellular basis for a hapten-specific state of tolerance induced in vitro. 8 Dec 28

The major allergen of ragweed pollen, antigen E, was modified by coupling its amino acid groups with either methanol, methoxypolyethylene glycol (MPEG) of 5,000 daltons, or a synthetic copolymer of D-glutamic acid and D-lysine (DGL) of 34,000 daltons, all appropriately activated. The conjugates were characterized chemically and immunologically. Compared to the native antigen, the methoxy conjugate showed little reduction in allergenic activity, but the other two conjugates showed strong reductions, as measured by heterologous passive cutaneous anaphylaxis in rats sensitized with murine anti-antigen E reaginic sera. The MPEG conjugate was apparently nonimmunogenic in mice known to be high responders to the native antigen. MPEG and DGL conjugates retained the immunosuppressive property of the native antigen as subcutaneous treatment of antigen E sensitized mice with these two conjugates led to significant long-lasting depression of their antigen E-specific IgE and IgG antibody levels. These immunological changes are believed to result from reduction of antigenic valency and specificity upon coupling the bulky molecules to the protein antigens.
 ...
PMID:Immunological properties of conjugates of ragweed pollen antigen E with methoxypolyethylene glycol or a copolymer of D-glutamic acid and D-lysine. 8 43

The regulation of dihydrodipicolinate synthase (EC 4.2.1.52) and aspartate kinase (EC 2.7.2.4) was studied in Bacillus subtilis 168. Starvation for lysine gave depression of one aspartate kinase isoenzyme but not of dihydrodipicolinate synthase. Strains resistant to growth inhibition by the lysine analogue thiosine exhibited constitutively derepressed synthesis of one aspartate kinase isoenzyme but had normal levels of dihydrodipicolinate synthase. The data provide strong evidence that lysine is not the signal for derepression of dihydrodipicolinate synthase. Nevertheless, dihydrodipicolinate synthase specific activity increased during sporulation, and it is suggested that this increase may result, in part, from resistance to proteolysis of that enzyme.
 ...
PMID:Regulation of dihydrodipicolinate synthase and aspartate kinase in Bacillus subtilis. 16 19

The authors studied the dynamics of natural substrates of neurohumoral origin (oxytocin and lysine-vasopressin) by the serum of pregnant and nonpregnant women in relation to the pH in the medium, within pH limits of 2.5 to 8. The values obtained in a polarographic study of depression of the complex oxytocin and lysine-vasopressin polarographic wave by pregnancy and non-pregnancy sera and the results of a parallel analysis of free amino acids of the inactivated substrates under the same conditions showed that, apart from deep degradation of the studied substrates at the optimum pH (5.5 minus 8), less pronounced degradation of the molecule at low pH values (3 minus 4,5), i.e. in a non-physiological blood medium, also occurred. On the basis of their results, the authors submit the hypothesis of the existence of oxytocinase isoenzymes and of the probable presence of several peptidases with overlapping specificity.
 ...
PMID:The influence of pH in the medium on degradation of neurohormones by pregnancy serum. 23 51

Syntheses of chromosomal proteins was studied in relation to DNA syntheses in the rat thymus following whole-body X-irradiation (600 rad). There was a considerable depression of the syntheses of DNA and histones during the first 4--48 hours after irradiation. The syntheses of histones H3 and H4 plus H2A were affected to a much greater degree than those of histones H1 and H2B, suggesting a tight coupling between the syntheses of DNA and histones H3 and H4 plus H2A. A part of the lysine-rich histones H1 and H2B, however, seems to be synthesized, even in the absence of DNA synthesis. Biosynthesis of non-histone proteins was also depressed in the thymus after irradiation. The degree of inhibition, however, was very low, except for the syntheses of a few non-histone protein components which were depressed to a considerable extent. This implies that the synthesis of the majority of non-histone proteins is independent of DNA synthesis.
 ...
PMID:Syntheses of DNA and chromosomal proteins in the rat thymus following whole-body X-irradiation. 30 73

The ability of low protein diets containing small neutral, dispensable amino acids to induce threonine imbalance has been examined. Diets containing amino acids which compete for threonine transport in vitro (serine, alanine, alpha-amino-n-butyrate) caused depressions of growth and food intake which could be corrected to varying degrees by adding threonine to the diet. Large neutral, indispensable amino acids, moderately inhibitory of threonine transport, also induced the imbalance. Some amino acids that had little or no effect on threonine transport in vitro (acidic amino acids and proline) did not cause growth and food intake depressions. Other non-inhibitory amino acids (arginine and lysine) caused growth depressions which were not satisfactorily corrected by additional threonine alone, but were prevented by supplements of all the indispensable amino acids including threonine. Ornithine which was also not inhibitory of threonine transport was an exception. It induced a moderate growth depression which was corrected by additional threonine. Similar studies showed that histidine or tryptophan imbalance could be induced by feeding diets containing only those large neutral amino acids which compete for histidine or tryptophan transport in vitro. These experiments show that, based on the results of transport competition experiments, it is generally possible to devise amino acid supplements which can induce a dietary imbalance of a given amino acid.
 ...
PMID:Induction of threonine imbalance by dispensable amino acids: relation to competition for amino acid transport into brain. 43 Feb 32

The effects of several types of vasopressin analogs that are considered to be resistant to some of the physiologically significant enzymatic systems were investigated utilizing rats trained in a passive avoidance task. Enhancement of avoidance latencies was observed 2, 7 and 13 days after the single learning trial when deamino-carbavasopressins, triglycyl-8-lysine-vasopressin or its des-glycinamide derivative, and deamino-D-arginine-vasopressin were given shortly after the learning trial in the dose of 1 microgram s.c. (8-L-Arginine)deamino-6-carba-vasopressin and (8-L-ornithine)deamino-6-carba-vasopressin were also active in the dose of 0.1 microgram. Lysine vasopressin and its des-glycinamide derivative failed to enhance avoidance latencies in part of the experiments if doses of 0.3--3 micrograms were administered and 7 or 13 day intervals were used between the learning and the test trials. Enhancement of avoidance latencies was also observed, if some of the peptides were injected 20 min but not 120 or 180 min before the test trial. Marked depression of exploratory behavior of rats in an open field was found after s.c. injections of low doses (1--3 micrograms kg-1) of deamino-carba-vasopressins. Higher doses (10--30 micrograms kg-1) induced sleep-like immobility not accompanied by ataxia or catalepsy.
 ...
PMID:Vasopressin analogs: sedative properties and passive avoidance behavior in rats. 47 29

Lysine supplementation of the growth medium of a wild type strain of the yeast Saccharomycopsis lipolytica specifically results in saccharopine dehydrogenase repression. Starvation of the strain for histidine triggers a general depression of various histidine, leucine, arginine and lysine biosynthetic enzymes, including saccharopine dehydrogenase. These two types of control, specific and general, act independently on saccharopine dehydrogenase expression, since mutants which fail to respond to the specific control still are sensitive to the general one. These mutants were first selected as unable to catabolize lysine, suggesting that a link may exist between saccharopine dehydrogenase specific regulation and activity of the catabolic pathway.
 ...
PMID:General and lysin specific control of saccharopine dehydrogenase levels in the yeast Saccharomycopsis lipolytica. 48 78

Substantial genetic, variability for grain protein content in wheat has been identified. In appropriate combinations known genes can increase protein content of wheat grain by 5 percentage points. Productive high protein experimental lines with good agronomic traits and satisfactory processing attributes have been identified. A high protein hard red winter variety developed in Nebraska was released for commercial production in 1975 under the name "Lancota". The high protein of Lancota resides entirely in the starchy endosperm portion of the kernel and is fully transmissible to white milled flour. The high protein of Lancota results from elevated NO3 reductase activity, increased N-absorption by the roots, and more complete translocation of N to the grain. Despite strong environmental influence on wheat protein level, genes for high protein have been demonstrated to effectively increase protein content in many different production environments. Lysine % of protein decreases but lysine % of grain increases as protein is increased. Genetic variability for lysine of sufficient magnitude to overcome the normal depression of lysine % of protein as protein is increased has been uncovered. Experimental lines have been developed in the ARS-Nebraska program in which genes for high protein and high lysine were combined. The lines have been widely distributed for use in other breeding programs.
 ...
PMID:Improvement of wheat protein quality and quantity by breeding. 72 17


1 2 3 4 5 6 7 8 9 10 Next >>