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...

Bacteriophage T5 induces a deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase) activity during infection of Escherichia coli. A T5 mutant (T5 dut) unable to induce this dUTPase activity has been isolated. Although this mutant is viable, the E. coli dUTPase activity is not sufficiently active to exclude uracil from the progeny DNA and about 3% of the thymine is replaced by uracil. When th...

The stereoselective synthesis of some 3’-deoxy-3’-C-methyl pyrimidine nucleosides is reported. studied modifications concern the inversion configuration in 2’-position as well introduction fluoro and azido substituents. corresponding arabinonucleoside 2’-substituted ribonucleoside analogs uracil cytosine have been obtained fully characterized. Attempts to introduce substituents with at C-2’ are...

Phage PBS-2 DNA, which contains uracil in place of thymine, was selectively damaged and then used as substrate for purified Bacillus subtilis uracil-DNA glycosylase. This enzyme releases uracil from DNA in a limited processive manner. Irradiation by ultraviolet light (greater than 305 nm) in the presence of isopropanol and a free radical photoinitiator introduced covalently bound 8-(2-hydroxy-2...

The degradation of uracil in regenerating rat liver has been investigated by Canellakis et al. (2, 3) and, more recently, by Skijld (4). Uracil labeled with C?4 in the ureido carbon was incubated with rat liver slices (2, 3) and with the particle-free supernatant fraction obtained by centrifugation of rat liver homogenates (4). The formation of CY402 was used as a measure of the breakdown of ur...

A thymine-requiring mutant of Bacillus subtilis strain 168 accumulates short DNA chains after brief pulses with [(3)H]thymidine. Reversion of the thy mutation to thy(+) abolishes the accumulation of short DNA chains, suggesting that the accumulation is related to the thy mutation. The reason for this accumulation has been further investigated by analysis of a mutant with a defective uracil-DNA ...

Uracil is incorporated into newly synthesized DNA by mutants of Escherichia coli with reduced levels of dUTPase (dUTP nucleotidohydrolase; EC 3.6.1.23). Excision-repair of the incorporated uracil results in the generation of labeled DNA fragments that appear after brief pulses with [(3)H]thymidine [Tye, B-K., Nyman, P.-D., Lehman, I. R., Hochhauser, S. & Weiss, B. (1977) Proc. Natl. Acad. Sci. ...

The tumor-promoting effect of uracil-induced calculi on rat urinary bladder carcinogenesis was investigated in male F344 rats pretreated with /V-butyl-A/-(4-hydroxybutyl)nitrosamine (BBN). Since uracil-in duced calculi and papillomatosis of the bladder are reversible, uracil was given for a limited period after the treatment with BBN. Animals were given 0.05% BBN in their drinking water for 4 w...

In the title compound, C(13)H(16)O(4), the terminal carboxyl-ate groups are twisted to each other at a dihedral angle of 23.80 (9)°. Weak inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into supra-molecular chains along the a axis.