The Escherichia coli gene purR, encoding a repressor protein, was cloned by complementation of a purR mutation. Gene purR on a multicopy plasmid repressed expression of purF and purF-lacZ and reduced the growth rate of host cells by limiting the rate of de novo purine nucleotide synthesis. The level of a 1.3-kilobase purR mRNA was higher in cells grown with excess adenine, suggesting that synth...

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder seen in Fragile X premutation carriers. Previous studies found that Fragile X rCGG repeats are sufficient to cause neurodegeneration and that the rCGG repeat-binding proteins Pur α and hnRNP A2/B1 can modulate rCGG-mediated neuronal toxicity. To explore the role of Pur α in rCGG-mediated neurodegeneration furthe...

While studying a set of multiply marked mutants of Staphylococcus aureus strain 8325 by transformation, several instances of apparent genetic linkage were encountered. After showing that these linked transformations were readily inactivated by shearing of the deoxyribonucleic acid (DNA) but were resistant to dilution of the DNA, and showing that mixtures of DNA failed to form double transforman...

PURPOSE To report our results on urinary continence after bladder neck preservation (BNP) and posterior urethral reconstruction (PUR) during robot-assisted laparoscopic radical prostatectomy (RALP). MATERIALS AND METHODS Data from 107 patients who underwent RALP were compared on the basis of whether the patients underwent BNP and PUR, BNP only, or the standard technique (ST). In group A (n=31...

The halocarbon CFC-11 has extensively been used as a blowing agent for polyurethane (PUR) insulation foams in home appliances and for residential and industrial construction. Release of CFCs is an important factor in the depletion of the ozone layer. For CFC-11 the future atmospheric concentrations will mainly depend on the continued release from PUR foams. Little is known about rates and time ...

Herein, a novel polypropylene/polyurethane rubber (PP/PUR) was prepared based on thermoplastics vulcanizates (TPV)/layered double hydroxide (LDH) nanocomposite in the presence of 3-(triethoxysilyl)propylsuccinic anhydride (SSA) intercalated LDH (SSA-LDH). The effect SSA-LDH explored thermo-mechanical, thermal, morphological, rheological, and mechanical properties as well gel content, compressio...

Abstract. We determine the asymptotical satisfiability probability of a random at-most-k-Horn formula, via a probabilistic analysis of a simple version, called PUR, of positive unit resolution. We show that for k = k(n) → ∞ the problem can be “reduced” to the case k(n) = n, that was solved in [17]. On the other hand, in the case k = constant the behavior of PUR is modeled by a simple queuing ch...

The postentry restriction of HIV-1 replication in monocytes can be relieved when they differentiate to dendritic cells (DCs) or macrophages. Multiple mechanisms have been proposed to interpret the differentiation-dependent susceptibility of monocytes to HIV-1 infection, and the absence of host-cell-encoded essential factors for HIV-1 completing the life cycle may provide an explanation. We have...

Thiamine is thought to be synthesized by two alternative pathways, one involving the first four enzymes of the purine pathway and a second that can function independently of the purine pathway. Insertion mutations in purG and purI prevent thiamine synthesis through the alternative pyrimidine biosynthetic (APB) pathway under aerobic but not anaerobic growth conditions. In contrast, point mutatio...