Route of tracer administration does not affect ileal endogenous nitrogen recovery measured with the 15N-isotope dilution technique in pigs fed rapidly digestible diets. (1/47)

The (15)N-isotope dilution technique ((15)N-IDT), with either pulse-dose oral administration or continuous i.v. administration of [(15)N]-l-leucine (carotid artery), both at 5 mg/(kg body weight . d), was used to measure ileal (postvalve T-cecum cannula) endogenous nitrogen recovery (ENR) in pigs (9 +/- 0.6 kg). Diets were cornstarch, enzyme-hydrolyzed casein with no (control) or high (4%) content of quebracho extract (Schinopsis spp.) rich in condensed tannins. Blood was sampled from a catheter in the external jugular vein. Mean plasma (15)N-enrichment at d 8-10 was higher (P = 0.0009) after i.v. than after oral administration [0.0356 vs. 0.0379 atom% excess (APE)]. Plasma (15)N-enrichment for i.v. infused pigs was 0.01117 APE higher (P < 0.0001) and for orally dosed pigs 0.0081 APE lower (P < 0.0001) at 11 h postprandial compared with 1 h postprandial. Apparent ileal N digestibility was higher (P < 0.0001) for the control (85.5%) than for the quebracho diet (69.5%). ENR was calculated from the ratio of (15)N-enrichment of plasma and digesta. The ENR for the quebracho diet was approximately 300% higher than for the control diet (6.03 vs. 1.94 g/kg dry matter intake, P < 0.001). The real N digestibility (92.2 +/- 0.4%) was equal for both diets (P = 0.1030) and both tracer methods (P = 0.9730). We concluded that oral administration of [(15)N]leucine provides reasonable estimates of ENR in pigs fed semipurified diets with high or low content of tannins; however, one must be careful in extrapolating this conclusion to studies with other protein sources or feeding frequencies.  (+info)

Ileal endogenous nitrogen recovery is increased and its amino acid pattern is altered in pigs fed quebracho extract. (2/47)

Ileal endogenous nitrogen recovery (ENR) in pigs (9 +/- 0.6 kg body weight) was estimated simultaneously using the (15)N-isotope dilution technique ((15)N-IDT) and the peptide alimentation ultrafiltration (UF) method. Diets were cornstarch, enzyme-hydrolyzed casein with no (control) or high (4%) content of quebracho extract (Schinopsis spp.) rich in condensed tannins. The amino acid (AA) pattern of the ENR was also determined. The ENR of pigs fed the quebracho diet was higher (P = 0.0001) than that of pigs fed the control diet [6.00 vs. 1.95 g/kg dry matter intake (DMI) for the (15)N-IDT and 5.18 vs. 1.49 g/kg DMI for the UF method, respectively]. With the (15)N-IDT, ENR values were 0.44-0.79 g/kg DMI (24%) higher (control P = 0.0032, quebracho P = 0.0002) than for the UF method. Apparent nitrogen digestibility depended on diet (69.0% quebracho vs. 86.0% control, P = 0.0001). Real nitrogen digestibility (RD-N) determined by the UF method was higher (P = 0.0001) for the control than for the quebracho diet (91.4 vs. 88.2%). Corresponding values for the (15)N-IDT did not differ (P = 0.0569) between diets (92.8 vs. 91.4%). The (15)N-IDT gave higher values for RD-N of both diets (control P = 0.0030, quebracho P = 0.0002) compared with the UF method. Endogenous AA recoveries (g/kg DMI) were increased 300% (P = 0.0001) and the AA-pattern of ENR was changed (P from 0.0001 to 0.7530 for different AA) by the quebracho diet. A constant AA-pattern of ENR cannot be assumed. Despite limitations of both techniques, the (15)N-IDT and the UF method gave similar results with respect to ENR.  (+info)

Domestication of a Mesoamerican cultivated fruit tree, Spondias purpurea. (3/47)

Contemporary patterns of genetic variation in crops reflect historical processes associated with domestication, such as the geographic origin(s) of cultivated populations. Although significant progress has been made in identifying several global centers of domestication, few studies have addressed the issue of multiple origins of cultivated plant populations from different geographic regions within a domestication center. This study investigates the domestication history of jocote (Spondias purpurea), a Mesoamerican cultivated fruit tree. Sequences of the chloroplast spacer trnG-trnS were obtained for cultivated and wild S. purpurea trees, two sympatric taxa (Spondias mombin var. mombin and Spondias radlkoferi), and two outgroups (S. mombin var. globosa and Spondias testudinus). A phylogeographic approach was used and statistically significant associations of clades and geographical location were tested with a nested clade analysis. The sequences confirm that wild populations of S. purpurea are the likely progenitors of cultivated jocote trees. This study provides phylogeographic evidence of multiple domestications of this Mesoamerican cultivated fruit tree. Haplotypes detected in S. purpurea trees form two clusters, each of which includes alleles recovered in both cultivated and wild populations from distinct geographic regions. Cultivated S. purpurea populations have fewer unique trnG-trnS alleles than wild populations; however, five haplotypes were absent in the wild. The presence of unique alleles in cultivation may reflect contemporary extinction of the tropical dry forests of Mesoamerica. These data indicate that some agricultural habitats may be functioning as reservoirs of genetic variation in S. purpurea.  (+info)

Polyphenols purified from the Brazilian aroeira plant (Schinus terebinthifolius, Raddi) induce apoptotic and autophagic cell death of DU145 cells. (4/47)

Polyphenols extracted from many plants have shown antiproliferative and antitumor activities in a wide range of carcinogenesis models. The antiproliferative effects of polyphenols purified from the Brazilian aroeira plant (Schinus terebinthifolius, Raddi) were investigated on the androgen-insensitive DU145 human prostatic carcinoma cell line. A F3 fraction purified from leaf extract inhibited the DU145 cell proliferation more than 30-fold compared to the crude extract. By flow cytometric analysis, the polyphenol fraction was demonstrated to induce G0/G1 cell growth arrest and cell apoptosis. This apoptosis was evidenced by caspase 3 stimulation in F3-treated cells as compared to crude extract treated cells. The acid phosphatase activity of lysosomes was strongly activated in the lysosomal fraction of the F3-treated DU145 cells. This lysosomal activation, together with the appearance of autophagic vacuoles, suggests that "type 2 physiological cell death" was also involved in this antiproliferative effect. HPLC analysis of this F3 fraction showed 18 different subfractions. Among these subfractions, F3-3, F3-7 and F3-13 strongly inhibited DU145 cell proliferation in a dose-dependent manner. However, the nature of these polyphenols remains unknown since only one (Isoquercitrin) of the tested pure polyphenols co-migrated with F3-13. Since lysosomotropic drugs are considered as possible regulators of lysosome activity, aroeira polyphenols could target lysosomes of prostatic cancer cells to induce autophagic cell death.  (+info)

General synthesis for chiral 4-alkyl-4-hydroxycyclohexenones. (5/47)

[reaction: see text] Some selective transformations of resorcinol-derived cyclohexadienone are reported. Efforts led to a structure reported to display anticancer properties. On the basis of the results, the structures for natural products reported to contain a 4,6-dihydroxy-4-alkyl-cyclohexenone nucleus are corrected.  (+info)

Vasorelaxant and hypotensive effects of Sclerocarya birrea (A Rich) Hochst (Anacardiaceae) stem bark aqueous extract in rats. (6/47)

The vasorelaxant and hypotensive effects of Sclerocarya birrea stem bark aqueous extract have been examined in rat experimental paradigms. Cumulative additions of S birrea stem bark aqueous extract (SBE 12.5-200 mg/ml) to the bath fluid induced concentration-dependent relaxations of endothelium- containing normotensive Wistar rat isolated aortic rings pre-contracted with noradrenaline (NA). The vasorelaxant effect of SBE on endothelium-containing isolated aortic rings was annulled by removal of the functional endothelium (in endothelium-denuded normotensive Wistar rat isolated aortic rings), or by pretreatment of the endothelium-containing isolated aortic rings with NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthase (NOS). Bolus intravenous administrations of the plant extract (SBE 25-400 mg/kg iv) caused transient, dose-dependent and significant (p < 0.05-0.001) reductions in systemic arterial blood pressure and heart rates of anaesthetised normotensive and hypertensive Dahl salt-sensitive rats. The findings of this experimental animal study suggest that S birrea stem bark aqueous extract relaxes normotensive Wistar rat aortic vascular smooth muscle via endothelium-dependent nitric oxide (NO); and that the hypotensive effect of the plant extract is likely to be mediated, at least in part, through nitric oxide synthase activation and subsequent nitric oxide release.  (+info)

Induction of apoptosis on human hepatocarcinoma cell lines by an alkyl resorcinol isolated from Lithraea molleoides. (7/47)

AIM: To study the mechanism of cytotoxicity of a new active 5-alkyl resorcinol [1, 3-dihydroxy-5- (tridec-4', 7'-dienyl) benzene] isolated from Lithraea molleoides leaves on liver tumor cells. METHODS: Human hepatocarcinoma cell lines (HepG2 and Hep3B) in culture were treated with inhibitory concentrations, 50% of the compound, for 24 h. The induction of apoptosis was detected in treated cells by analysis of DNA fragmentation, DNA content, and acridine orange and propidium iodide staining. RESULTS: After 24 h of 5-alkyl resorcinol treatment, both cell lines showed: (1) the typical morphological alterations of apoptosis; (2) DNA fragmentation, detected by laddering and appearance of a subG0 population by flow cytometry; and (3) condensed and fragmented nuclei by acridine orange-propidium iodide staining. CONCLUSION: Based on the results, this compound exerts its cytotoxic effect in both hepatocellular cell lines through apoptotic cell death. For Hep3B, cells with mutated p53 and Fas, apoptosis would proceed by p53- or Fas-independent pathways.  (+info)

Colonization patterns of the invasive Brazilian peppertree, Schinus terebinthifolius, in Florida. (8/47)

Invasive species are believed to spread through a process of stratified dispersal consisting of short-distance diffusive spread around established foci and human mediated long-distance jumps. Brazilian peppertree (Schinus terebinthifolius), native to South America, was introduced twice as an ornamental plant into Florida, USA, just over 100 years ago. A previous study indicated that these two introductions were from genetically differentiated source populations in the native range. In this study, we took advantage of these contrasting genetic signatures to study the spatial spread of Brazilian peppertree across its entire range in Florida. A combination of spatial genetic and geostatistical analyses using chloroplast and nuclear microsatellite markers revealed evidence for both diffusive dispersal and long-distance jumps. Chloroplast DNA haplotype distributions and extensive bands of intra-specific hybridization revealed extensive dispersal by both introduced populations across the state. The strong genetic signature around the original introduction points, the presence of a general southeast to northwest genetic cline, and evidence for short-distance genetic spatial autocorrelation provided evidence of diffusive dispersal from an advancing front, probably by birds and small mammals. In the northernmost part of the range, there were patches having a high degree of ancestry from each introduction, suggesting long-distance jump dispersal, probably by the movement of humans. The evidence for extensive movement throughout the state suggests that Brazilian peppertree will be capable of rapidly recolonizing areas from which it has been eradicated. Concerted eradication efforts over large areas or the successful establishment of effective biocontrol agents over a wide area will be needed to suppress this species.  (+info)

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