In Paper I (l), it was shown that, in Escherichia co&, exogenous uracil can be converted to nucleic acid thymine and that the methyl group of methionine does not serve as a precursor of either bacterial thymine or bacteriophage thymine and hydroxymethylcytosine. Considerations as to the nature of the l-carbon precursor of the thymine methyl group and of possible biosynthetic mechanisms have led...

background: saccharomyces boulardii (s. boulardii) is the best known probiotic yeast. the genetic engineering of this probiotic strain requires the availability of appropriate mutants to accept various gene constructs carrying different selection markers. as the auxotrophy selection markers are under focus, we have generated a ura3 auxotroph mutant of s. boulardii for use in further genetic man...

Thymine and uracil have been shown to be rapidly catabolized by animal tissues in vitro and in vivo 1_4. Several 5-substituted halogen derivatives of uracil have also been reported to be degraded in the identical manner 5_8. S e b e s t a and coworkers 9 found that 5-substituted nitroand bromouracil inhibit the degradation of thymine and uracil by rat liver acetone powder. In a previous rep o r...

Knowledge of the mechanisms involved in pyrimidine metabolism is fundamental to the biochemistry of the nucleic acids. Cerecedo, Emerson, and Stekol (l-7) pioneered this field in their work with dogs. Their experiments, conducted by feeding the in vitro oxidation products of uracil and the estimation of excreted urea, culminated in the proposal of a mechanism for pyrimidine metabolism (8). More...

N-1 regioselective Michael-type addition of 5-substituted uracils to (2-hydroxyethyl) acrylate is presented. The reactions were performed in polar aprotic solvents and with avoidance of polymerization of acrylic substrate. The obtained adducts may serve as versatile substrates for further functionalization, e.g. into (3-uracil-1-yl)propanoic acids or transformations, with participation of hydro...

The present work includes synthesis of new series heterocyclic derivatives containing 6-amino-1,3-dimethyl uracil moiety linked to 1,2,4-triazole [6-8 and 10]. first way reaction 6-amino-1,3-dimethyluracil with ethyl chloroacetate K2CO3 as catalyst in DMF solvent gives ester derivative [1]. Then, compound [1] was converted into (semicarbazide, thiosemicarbazide, phenylsemicarbazide hydrazide de...

The reaction o f N.N'-dim ethylurea with l,5-dim ethyl-2,4-bis-(dim ethylam ino)-l,5-diaza-2,4-dibora-3-oxacyclohexan-6-one (2) in the melt proceeds with condensation of the urea to yield two major products: the acid l,3,5-trim ethyl-2-hydroxy-l,3,5-triaza-2-boracyclohexa-4,5-dione (la); and a mixture of the methylammonium (4a) and dimethylammonium salt (4b) of the anion [{C H 3N («-C O N C H 3...