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Some grain processing by-products rich in digestible fiber are good feed resources for ruminants. This experiment was conducted to investigate the effects of replacing a portion of corn and corn stover with the combinations of corn bran and soybean hulls in the diet of fattening lambs on nutrient digestion, rumen microbial protein synthesis, and growth performance. A total of 36 Dorper × Small Thin-Tailed crossbred ram lambs (BW = 22.2 ± 0.92 kg; mean ± SD) were randomly divided into three groups, and each group was fed 1 of 3 treatment diets: 1) 0% corn bran and soybean hulls (control); 2) 9% corn bran and 9% soybean hulls (18MIX); and 3) 17% corn bran and 17% soybean hulls (34MIX). The feeding experiment was conducted for 70 days, with the first 10 days for adaption. The DM intake was higher for 34MIX (1635.3 g/d) than for control diet (1434.7 g/d; P = 0.001). Lambs fed 18MIX and 34MIX diets (230.2 and 263.6 g/d, respectively) had higher average daily gain and feed efficiency than those fed control diet (194.8 g/d; P 0.05). The metabolizable protein supplies were improved with increasing co-products inclusion rate. The results indicated that corn bran and soybean hulls in combination can effectively replace a portion of corn and corn stover in the ration of finishing lambs with positive effect on nutrient digestion and growth performance.

To determine the endogenous contribution of purine derivatives (PD) to renal excretion and the urinary recovery of duodenal purine bases (PB), five dairy Granadina goats (initial weight ± s.e.: 38.6 ± 2.78 kg) were each fitted with a duodenal infusion catheter. Animals were offered ad libitum a mixed diet (75 : 25; alfalfa hay : concentrate), which was supplied in equal portions every 3 h. To label microbial PB, (15NH4)2SO4 was added to the concentrate. The lower enrichment of urinary PD (15N-allantoin) compared with duodenal PB enrichment confirmed the presence of an endogenous PD fraction (268.5 ± 21.98 μmol/kg weight0.75 or 0.386 of the total PD excretion). The recovery of PD in urine and milk increased linearly in response to increasing amounts of duodenally infused RNA (starting on day 21 after parturition). On average, 0.74 of infused PB from RNA was recovered in urine. Milk PD constituted a minor (

The experimental NMR methods and theoretical calculations of NMR parameters used in the studies of purine derivatives are reviewed. The first part of this chapter brings an overview of the experimental techniques that are commonly used for hydrogen, carbon and nitrogen NMR signal detection and assignment, followed by a detailed discussion of the influence of purine substitution on NMR parameters. The applications of solid-state NMR methods and the calculations of chemical shifts and indirect coupling constants of purines are also reviewed. The second part of this chapter summarises recent applications (since 2005) of these techniques in the studies of purine structure and interactions.

Based on recent reports that several (E)-8-styrylcaffeinyl analogues are potent reversible inhibitors of monoamine oxidase B (MAO-B), a series of 8-benzyloxycaffeinyl analogues were synthesized and evaluated as inhibitors of baboon liver MAO-B and recombinant human MAO-A and -B. The 8-benzyloxycaffeinyl analogues were found to inhibit reversibly both MAO isoforms with enzyme–inhibitor dissociation constants (Ki values) ranging from 0.14 to 1.30 lM for the inhibition of human MAO-A, and 0.023– 0.59 lM for the inhibition of human MAO-B. The most potent MAO-A inhibitor was 8-(3-methylbenzyloxy) caffeine while 8-(3-bromobenzyloxy)caffeine was the most potent MAO-B inhibitor. The analogues inhibited human and baboon MAO-B with similar potencies. A quantitative structure–activity relationship (QSAR) study indicated that the MAO-B inhibition potencies of the 8-benzyloxycaffeinyl analogues are dependent on the Hansch lipophilicity (p) and Hammett electronic (r) constants of the substituents at C-3 of the benzyloxy ring. Electron-withdrawing substituents with a high degree of lipophilicity enhance inhibition potency. These results are discussed with reference to possible binding orientations of the inhibitors within the active site cavities of MAO-A and -B. http://dx.doi.org/10.1016/j.bmc.2009.12.064 http://www.journals.elsevier.com/bioorganic-and-medicinal-chemistry/ Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.bmc.2009.12.064. National Research Foundation; Medical Research Council, South Africa.

Methanolic extracts of the Brazilian endemic ascidian Eudistoma vannamei have been extensively studied for their cytotoxic activity against several human cancer cell lines. Previous work reported the occurrence of purine derivatives and staurosporine alkaloids as the major nitrogen-containing compounds. In this study, we report the occurrence of three pyrimidine alkaloids in addition to cholesterol, sitosterol and stigmasterol. Keywords: Pyrimidine, Tunicate, Steroids, Nucleosides

Publisher Summary This chapter describes the effect of epinephrine on liver ribonucleic acids and 5-nucleotidase. In a series of experiments, it is found that adrenaline produces a significant increase on the excretion of purine derivatives in rats. It is found that after administration of adrenaline the activity of liver 5-nucleotidase was increased, while there is no change on the concentration of purines or ribonucleic acids. When adrenaline was added in liver homogenates the activity of 5-nucleotidase and the level of purine derivatives were increased. There is also an increased breakdown of ribonucleic acids, although a concomitant increase of liver ribonuclease activity was not observed.

Publisher Summary This chapter presents an overview on purine N-oxides and cancer. The oxidative transformation of purines into N-oxide derivatives that are potent oncogenic agents introduces the possibility that such derivatives may play a role in the origin of spontaneous cancers. Some of the chemical and biological information about N-oxides collected in the chapter may be important in deciphering the enigma of a purine derivative redirecting growth into disorder. Heterocyclic N-oxides have received attention from organic chemists because of their utility in the syntheses of variously substituted nitrogen-heterocycles and, more recently, because of the discovery of the heterocyclic AT-oxide group in several antibiotics. The presence of the N-oxide introduces some profound differences from the parent purines in the behaviors of both the ring system and of substituents. In purine N-oxides, there is almost always an active hydrogen that can tautomerize, more or less readily, to the oxygen of the N-oxide.