Twenty-four multiparous dairy cows (eight with ruminal cannulae) were blocked by days in milk and assigned to six balanced 4 x 4 Latin squares with 21-d periods. The four diets, formulated from alfalfa silage plus a concentrate mix based on ground high moisture ear corn, contained (dry matter basis): 1) 20% concentrate, 80% alfalfa silage (24% nonfiber carbohydrate; NFC), 2) 35% concentrate, 65...

BACKGROUND The aim of the study was to measure the content of methylated purines that appear as admixtures in uric acid stones. METHODS We analyzed urinary calculi from 48 residents of Western Pomerania who underwent surgery at the urology ward in Szczecin. Stone samples were dissolved in 0.1 mol/L NaOH. Extracts were diluted in 50 mmol/L KH(2)PO(4) and analyzed by reversed-phase HPLC with ul...

In earlier papers the presence of protein decomposition products in soils was reported and it was shown that in soils the changes occurring in the decay of such plant and animal materials as get into the soil are similar to the changes occuring under other conditions in the laboratory or in nature. The presence of arginine and histidine in soils was definitely established by isolating these deg...

The solution conformations of 2-substituted derivatives of 1-(beta-D-ribofuranosyl)benzimidazole have been determined by circular dichroism spectroscopy in aqueous solutions. It is shown that analogs with methyl, amino, or methylamino substituents at position 2 of the benzimidazole ring (position 8 of the purine ring) have predominantly anti conformations, whereas analogs with chloro, aza, meth...

In earlier papers the presence of protein decomposition products in soils was reported and it was shown that in soils the changes occurring in the decay of such plant and animal materials as get into the soil are similar to the changes occuring under other conditions in the laboratory or in nature. The presence of arginine and histidine in soils was definitely established by isolating these deg...

In earlier papers the presence of protein decomposition products in soils was reported and it was shown that in soils the changes occurring in the decay of such plant and animal materials as get into the soil are similar to the changes occuring under other conditions in the laboratory or in nature. The presence of arginine and histidine in soils was definitely established by isolating these deg...

The pathway for the utilization of 2,6-diaminopurine (DAP) as an exogenous purine source in Salmonella typhimurium was examined. In strains able to use DAP as a purine source, mutant derivatives lacking either purine nucleoside phosphorylase or adenosine deaminase activity lost the ability to do so. The implied pathway of DAP utilization was via its conversion to DAP ribonucleoside by purine nu...

BACKGROUND Based on some previous research, the chalcone derivatives exhibited potent xanthine oxidase inhibitory activity, e.g. sappanchalcone (7), with IC50 value of 3.9 μM, was isolated from Caesalpinia sappan. Therefore, objectives of this research are design and synthesis of 7 and other chalcone derivatives by Claisen-Schmidt condensation and then evaluate their XO inhibitory activity. R...

Purine inhibitors of cyclin-dependent kinases attract attention as potential anticancer drugs because their first representative roscovitine recently entered clinical trials. Although well described in terms of structure-activity relationships, we still present here a novel modification of the purine scaffold influencing their inhibitory properties. The introduced C-8 substituents, however, low...

C6-Alkylated purine analogues were obtained in good to excellent isolated yields by S(N)Ar reaction of 6-chloropurine derivatives with 3-alkyl-acetylacetone. 3-Alkyl-acetylacetones were employed as alkylating agents and C6-alkylated purines were obtained highly selectively within short reaction time under microwave irradiation conditions. This work is complementary to the classical coupling rea...