Antibiotic resistance of coliforms in drinking water in rural areas.

The antibiotic sensitivity of 197 coliform sp. isolated from drinking water in five rural areas was studied. Twelve strains (6.

Cloning and physical characterization of linked lysine genes (lys4, lys15) of Saccharomyces cerevisiae.

The plasmid pSC4 which carries a 7.8 kb yeast DNA insert at the BamHI site of the Vector YEp13, complemented simultaneously MO-59-13c lys4, LU75 lys15 and LU32 lys4lys15 (double) mutations of Saccharomyces cerevisiae. The 1.

Properties of revertants of lys2 and lys5 mutants as well as alpha-aminoadipate-semialdehyde dehydrogenase from Saccharomyces cerevisiae.

alpha-Aminoadipate-semialdehyde dehydrogenase catalyzes the conversion of alpha-aminoadipate to alpha-aminoadipate-semialdehyde in the biosynthetic pathway of lysine in yeasts and molds. Mutants belonging to lys2 and lys5 loci of Saccharomyces cerevisiae lacked the alpha-aminoadipate-semialdehyde dehydrogenase activity. Complementation in vitro was demonstrated by combining the extracts from different lys2 and lys5 mutants.

Retinal organisation in a hill-stream cyprinid, Crossocheilus latius latius Hamilton.

The retinal organisation of a cyprinid fish, Crossocheilus latius latius Hamilton, which inhabits the sub-Himalayan torrents of Sikkim, India, has been studied by light microscopy. The fish are small and cylindrical having relatively large eyes with a large, oval pupil. They are adapted to the low-light level of the hill-torrents, which is caused by the heavily silted monsoon water.

Lysine biosynthesis pathway and biochemical blocks of lysine auxotrophs of Schizosaccharomyces pombe.

The alpha-aminoadipate (AA) pathway for the biosynthesis of lysine was investigated in the wild type and in lysine auxotrophs of the fission yeast Schizosaccharomyces pombe. Of the eight enzyme activities of the AA pathway that have been examined so far, six were present in the extract of wild-type S. pombe cells.

Cloning and biochemical characterization of LYS5 gene of Saccharomyces cerevisiae.

In Saccharomyces cerevisiae, the functions of two unlinked genes (LYS2 and LYS5) are required for the synthesis of the lysine biosynthetic enzyme, alpha-aminoadipate reductase. The LYS5 gene of S. cerevisiae was cloned by functional complementation of a lys5 mutant, X4004-3A, using a YEp24 plasmid library.

Biosynthetic and regulatory role of lys9 mutants of Saccharomyces cerevisiae.

Derepression of lysine biosynthetic enzymes of Saccharomyces cerevisiae was investigated in lys9 auxotrophs which lack saccharopine reductase activity. Five enzymes (homocitrate synthase, homoisocitrate dehydrogenase, alpha-aminoadipate aminotransferase, alpha-aminoadipate reductase and saccharopine dehydrogenase) were constitutively derepressed in all lys9 mutants with up to eight-fold higher enzyme levels than in isogenic wild-type cells. Levels of these enzymes in lys2, lys14, and lys15 mutants were the same or lower than those in wild-type cells.

Purification and properties of saccharopine dehydrogenase (glutamate forming) in the Saccharomyces cerevisiae lysine biosynthetic pathway.

Saccharopine dehydrogenase (glutamate forming) of the biosynthetic pathway of lysine in Saccharomyces cerevisiae was purified 1,122-fold by using acid precipitation, ammonium sulfate precipitation, DEAE-Sepharose, gel filtration, and Reactive Red-120 agarose chromatography. The enzyme exhibited a native molecular size of 69,000 daltons by gel filtration and consisted of a single 50,000-dalton polypeptide based upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme was readily denatured by exposures to temperatures exceeding 46 degrees C.

Regulation of phosphoenolpyruvate carboxykinase and pyruvate kinase in Saccharomyces cerevisiae grown in the presence of glycolytic and gluconeogenic carbon sources and the role of mitochondrial function on gluconeogenesis.

Phosphoenolpyruvate carboxykinase (PEPCKase) and pyruvate kinase (PKase) were measured in Saccharomyces cerevisiae grown in the presence of glycolytic and gluconeogenic carbon sources. The PEPCKase activity was highest in ethanol-grown cells. However, high PEPCKase activity was also observed in cells grown in 1% glucose, especially as compared with the activity of sucrose-, maltose-, or galactose-grown cells.

General and specific controls of lysine biosynthesis in Saccharomyces cerevisiae.

Six of the eight enzymes of the alpha-aminoadipate pathway for the biosynthesis of lysine in Saccharomyces cerevisiae were examined for repressibility to lysine and for susceptibility to the general control of amino acid biosynthesis. All of the enzymes exhibited a 2 to 4 fold lower level of specific activity in the wildtype strain X2180 when grown in lysine supplemented medium as compared to minimal medium. However, levels of only three of the enzymes, alpha-aminoadipate reductase, saccharopine reductase, and saccharopine dehydrogenase, were derepressed in the leaky lysine mutant 7305d and leaky arginine mutant 7853-6c when grown in minimal medium.

alpha-Aminoadipate pathway for the biosynthesis of lysine in lower eukaryotes.

Bacteria and green plants use the diaminopimelate pathway for the biosynthesis of the essential amino acid, lysine; however, yeast and other higher fungi use the alpha-aminoadipate (AA) pathway. The AA pathway has been investigated in detail biochemically, genetically, and in terms of regulatory mechanisms in the baker's yeast Saccharomyces cerevisiae. The genetic analysis of lysine auxotrophs of S.

Study of ascorbate status in murine and human leukaemias.

Since mice can synthesize ascorbic acid but man cannot, the ascorbate status in murine and human leukaemia was compared. The decline in plasma ascorbate concentration in both cases indicates that vitamin C deficiency occurs in malignancy. Analysis of tissue ascorbate values in mice also indicated that an enhanced rate of utilization of this vitamin occurs during malignancy, as does an increased rate of excretion, and both events may be responsible for vitamin C deficiency.

Two unlinked lysine genes (LYS9 and LYS14) are required for the synthesis of saccharopine reductase in Saccharomyces cerevisiae.

Three lysine auxotrophs, strains AU363, 7305d, and 8201-7A, were investigated genetically and biochemically to determine their gene loci, biochemical lesions, and roles in the lysine biosynthesis of Saccharomyces cerevisiae. These mutants were leaky and blocked after the alpha-aminoadipate step. Complementation studies placed these three mutations into a single, new complementation group, lys14.

Role of L-lysine-alpha-ketoglutarate aminotransferase in catabolism of lysine as a nitrogen source for Rhodotorula glutinis.

Wild-type and saccharopine dehydrogenaseless mutant strains of Rhodotorula glutinis grew in minimal medium containing lysine as the sole nitrogen source and simultaneously accumulated, in the culture supernatant, large amounts of a product identified as alpha-aminoadipic-delta-semialdehyde. The saccharopine dehydrogenase and pipecolic acid oxidase levels remained unchanged in wild-type cells grown in the presence of ammonium or lysine as the nitrogen source. Lysine-alpha-ketoglutarate aminotransferase activity was demonstrated in ammonium-grown cells.