Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

L-Asparagine uptake by Stemphylium botryosum is mediated by two distinct energy- and temperature-dependent transport systems. One permease is relatively specific for L-asparagine and L-glutamine and is present in nutrient-sufficient mycelium. The specific permease shows an optimum pH at 5.2, saturation kinetics (Km = 4.4 x 10(-4) M, Vmax = 1.1 mumol/g per min), competitive gradient of L-asparagine, and higher affinity towards the L-isomer of asparagine. Amide derivatives of L-asparagine (5-diazo-4-oxo-L-norvaline or L-aspartyl hydroxamate) are the most effective competitors, alpha-amino derivative (N-acetyl asparagine) is a moderate competitor, and alpha-carboxyl derivative (L-asparagine-t-butylester) shows only slight inhibition of the specific permease. Derivatives of L-glutamine are significantly less effective competitors than those of L-asparatine. The level of the specific permease is affected by nitrogen sources and increases approximately threefold upon starvation. The nonspecific permease possesses an optimum pH at 6.8, saturation kinetics (Km = 7 x 10(-5) M, Vmax = 5 mumol/g per min, Kt = 7.4 x 10(-5) M for L-leucine), and high affinity towards various types of amino acids.
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PMID:Characterization of L-asparagine transport systems in Stemphylium botryosum. 0 27

Amount of guanosine-5'-triphosphate, 3'-diphosphate (pppGpp) and guanosine-5'-diphosphate, 3'-diphosphate (ppGpp) in the cells of b. subtilis increased several times during starvation for lysine or after treatment with serine hydroxamate (analog of serine) or norvaline (analog of leucine), or in the presence of trimethoprim, which induced deficiency of methionine and leucine. In exponentially growing cells the concentration of pppGpp was found to be 10-20 pmol/A600. When serine hydroxamate or trimethoprim were added, concentration of pppGpp increased to 500-800 pmol/A600 and then slowly diminished. Elimination of lysine or addition to the culture medium of norvaline caused slight transitory accumulation of pppGpp (150 pmol/A600). The amount of another nucleotide ppGpp was always 2-3 times lower than one of pppGpp. Accumulation of (p)ppGpp in rel+ cells was accompanied by cessation of stable RNA synthesis. Under conditions described above rel- cells continued RNA synthesis and did not accumulate (p)ppGpp. In the rel+ cells treated with serine hydroxamate synthesis of stable RNA resumed and the amount of (p)ppGpp decreased after addition of serine or tetracycline and chloramphenicol. The half-life period for pppGpp in the presence of chloramphenicol was determined to be 30-40 seconds. Thus, during aminoacyl-tRNA deficiency rel+ cells of B. subtilis accumulate (p)ppGpp, which are believed to participate in negative regulation of RNA synthesis. Slight accumulation of pppGpp without concomitant inhibition of stable RNA synthesis was observed after treatment of growing cells with chloramphenicol.
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PMID:[Guanosine polyphosphate concentration and stable RNA synthesis in Bacillus subtilis following suppression of protein synthesis]. 616 Mar 84

Gc-ms and hplc have been employed to identify 5-hydroxy-L-norvaline (L-2-amino-5-hydroxypentanoic acid) in the culture fluids of pyridoxine-starved cultures of two pyridoxine auxotrophs of Escherichia coli B. The production of 5-hydroxynorvaline is shown to be secondary to pyridoxine starvation of the cultures, and the quantities of 5-hydroxynorvaline are similar to those of the common protein amino acids present in these cultures. This is the first time that 5-hydroxynorvaline has been identified as a product of bacterial metabolism.
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PMID:The identification of 5-hydroxy-L-norvaline in cultures of pyridoxine auxotrophs of Escherichia coli B. 822 10

Welker, N. E. (Western Reserve University, Cleveland, Ohio and University of Illinois, Urbana), and L. Leon Campbell. De novo synthesis of alpha-amylase by Bacillus stearothermophilus. J. Bacteriol. 86:1202-1210. 1963.-The pH optimum for the synthesis of alpha-amylase by washed-cell suspensions was 6.7. alpha-Amylase synthesis began soon after the addition of the inducer (maltose, methyl-beta-d-maltoside, or phenyl-alpha-d-glucoside, at 10(-3)m), proceeded at a linear rate for 60 min, and then leveled off. Cell suspensions without inducer produced small amounts of alpha-amylase. The addition of glucose (2 x 10(-3)m), sucrose (10(-3)m), or glycerol (4 x 10(-3)m) to washed-cell suspensions failed to stimulate the production of alpha-amylase. Nitrogen starvation of washed cells for 60 min with fructose as a carbon source or by induction with pure maltose showed that the ability to produce alpha-amylase was lost. Examination of the amino acid pool at this time showed a general depletion of amino acids and the complete disappearance of tyrosine, phenyl-alanine, proline, and valine. Replenishment of the amino acid pool with casein hydrolysate (0.5%) restored the ability of the cells to produce alpha-amylase. Chloramphenicol and 8-azaguanine were shown to inhibit alpha-amylase synthesis. Inhibition was observed immediately upon the addition of chloramphenicol to cell suspensions preinduced for varying periods of time. Actinomycin D and mitomycin C also inhibited alpha-amylase synthesis when added to induced washed-cell suspensions. The amino acid analogues, norvaline, norleucine, and ethionine, inhibited alpha-amylase formation by 72, 53, and 38%, respectively. p-Fluorophenylalanine inhibited the synthesis of active alpha-amylase by 92% and the incorporation of proline-C(14) into alpha-amylase and cellular proteins by 95 and 74%, respectively.
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PMID:DE NOVO SYNTHESIS OF ALPHA-AMYLASE BY BACILLUS STEAROTHERMOPHILUS. 1408 90

Interruption of the (p)ppGpp synthetase gene (rel) of Sorangium cellulosum So ce56 resulted in loss of ppGpp accumulation after norvaline treatment during exponential growth phase. The rel mutant failed to produce wild-type levels of the polyketides chivosazol and etnangien in production media. In wild-type cells expression of the chivosazol biosynthetic operon can be significantly increased by norvaline or alpha-methylglucoside. This induction does not occur in the rel mutant. The rel mutant also lost the capability to form multicellular fruiting bodies under nutrient starvation.
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PMID:Mutation in the rel gene of Sorangium cellulosum affects morphological and physiological differentiation. 1851 16