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101.
Huadong Chen Saeed Hayek Javier Rivera Guzman Nicholas D. Gillitt Salam A. Ibrahim Christian Jobin Shengmin Sang 《PloS one》2012,7(12)
Background
Theaflavins including theaflavin (TF), theaflavin-3-gallate (TF3G), theaflavin-3′-gallate (TF3′G), and theaflavin-3,3′-digallate (TFDG), are the most important bioactive polyphenols in black tea. Because of their poor systemic bioavailability, it is still unclear how these compounds can exert their biological functions. The objective of this study is to identify the microbial metabolites of theaflavins in mice and in humans.Methods and Findings
In the present study, we gavaged specific pathogen free (SPF) mice and germ free (GF) mice with 200 mg/kg TFDG and identified TF, TF3G, TF3′G, and gallic acid as the major fecal metabolites of TFDG in SPF mice. These metabolites were absent in TFDG- gavaged GF mice. The microbial bioconversion of TFDG, TF3G, and TF3′G was also investigated in vitro using fecal slurries collected from three healthy human subjects. Our results indicate that TFDG is metabolized to TF, TF3G, TF3′G, gallic acid, and pyrogallol by human microbiota. Moreover, both TF3G and TF3′G are metabolized to TF, gallic acid, and pyrogallol by human microbiota. Importantly, we observed interindividual differences on the metabolism rate of gallic acid to pyrogallol among the three human subjects. In addition, we demonstrated that Lactobacillus plantarum 299v and Bacillus subtilis have the capacity to metabolize TFDG.Conclusions
The microbiota is important for the metabolism of theaflavins in both mice and humans. The in vivo functional impact of microbiota-generated theaflavins-derived metabolites is worthwhile of further study. 相似文献102.
103.
Shafqat Nadeem Saeed Ahmad Tahira Fazeelat Muhammad Khawar Rauf Sadia Siddiq Abdul Hameed 《Inorganica chimica acta》2010,363(13):3261-3269
Palladium(II) complexes with triphenylphosphine (PPh3) and thioamides of the general formulae, [Pd(L)2(PPh3)2]Cl2 and [Pd(L)2(PPh3)2] have been prepared and characterized by elemental analysis, IR and NMR (1H, 13C and 31P) methods, and two of them (trans-[Pd(PPh3)2(Dmtu)2]Cl2·(H2O)(CH3OH)0.5 (1) and trans-[Pd(PPh3)2(Mpy)2] (2)) by X-ray crystallography; where L = thiourea (Tu), methylthiourea (Metu), N,N′-dimethylthiourea (Dmtu), tetramethylthiourea (Tmtu), 2-mercaptopyridine (Mpy), 2-mercaptopyrimidine (Mpm) and thionicotinamide (Tna). The spectral data of the complexes are consistent with the sulfur coordination of thioamides to palladium(II). The crystal structures of the complexes show that (1) has ionic character consisting of [Pd(PPh3)2(Dmtu)2]+2 cations and uncoordinated Cl− ions, while (2) is a neutral complex with Mpy behaving as anionic thiolate ligand. The coordination environment around palladium in (2) is nearly regular square-planar, while in (1) the trans angles show significant distortions from 180°. The complexes were screened for antibacterial effects, brine shrimps lethality bioassay and antitumor activity. These complexes showed significant activities in most of the cases against the tested bacteria as compared to that of a standard drug. Their antitumor activity against prostate cancer cells (PC3) is comparable with doxorubicin, together with no cytotoxic effects in brine shrimps lethality bioassay study. 相似文献
104.
105.
The emergence of pathogenic bacteria resistant to multiple antimicrobial agents is turning into a major crisis in human and veterinary medicine. This necessitates a serious re-evaluation of our approaches toward antibacterial drug discovery and use. Concurrent advances in genomics including whole-genome sequencing, genotyping, and gene expression profiling have the potential to transform our basic understanding of antimicrobial pathways and lead to the discovery of novel targets and therapeutics. 相似文献
106.
Tina Choe Saeed I Khan Miguel A Garcia-Garibay 《Photochemical & photobiological sciences》2006,5(5):449-451
While 1,6-biradicals produced by photodecarbonylation of dimethyl 11-oxodibenzo[c,h]bicyclo[4.4.1]undeca-3,8-diene-1,6-dicarboxylate (1) react exclusively by disproportionation in benzene solution, reactions in crystals lead to radical-radical combination reactions in almost quantitative yield. 相似文献
107.
Heat-stable enterotoxin (STa) isolated from bovine Escherichia coli strains was purified to homogeneity by growing the bacterial strains in a chemically defined medium, desalting, and concentrating the culture filtrate by batch adsorption chromatography on Amberlite XAD-2 resin, batch adsorption chromatography on reversed-phase silica, and preparative reversed-phase high-performance liquid chromatography. This rapid preparative purification scheme gave high recovery yields of pure STa which exhibited biochemical homology to STa purified by more complicated procedures. 相似文献
108.
The effect of lysolecithin (lysophosphatidylcholine) on the relaxation of rabbit aortic strip closely resembled that produced by acetylcholine (ACh) which releases the endothelium-derived relaxing factor (EDRF). Relaxation induced by lysolecithin depended on the presence of endothelium and was inhibited by hemoglobin and methylene blue. It appeared to be mediated by the second messenger, c-GMP. Lysolecithin induced relaxation was slower but more persistent than that resulting from the endothelium-derived relaxing factor (EDRF) produced by acetylcholine (ACh). Like lysolecithin, Triton X-100, a non-ionic detergent, also preferentially relaxed aortic strips with intact endothelium. The results demonstrate the importance of phospholipids derived from cell membranes in vascular smooth muscle relaxation. Endothelium-derived relaxing factors appear as a group of heterogeneous substances. 相似文献
109.
Mechanisms of resistance in the rice cultivar Manikpukha to the rice stem nematode Ditylenchus angustus 下载免费PDF全文
Shakhina Khanam Lander Bauters Richard Raj Singh Ruben Verbeek Ashley Haeck Saeed M. D. Sultan Kristof Demeestere Tina Kyndt Godelieve Gheysen 《Molecular Plant Pathology》2018,19(6):1391-1402
The incompatible interaction between the rice cultivar Manikpukha and the rice stem nematode Ditylenchus angustus has been reported recently. This research focuses on the underlying mechanisms of resistance in Manikpukha. Invasion, post‐infection development and reproduction of D. angustus were compared in compatible and incompatible interactions to identify the stage in which resistance occurs. The results indicate that resistance in Manikpukha is associated with reduced development and reproduction, implying that resistance acts post‐invasion. We studied the possible involvement of three classical defence hormones, salicylic acid (SA), jasmonic acid (JA) and ethylene (ET), in response to infection in a compatible interaction using biosynthesis/signalling‐deficient transgenic rice lines. All three hormones appear to have an influence on the basal defence of Nipponbare against the stem nematode. Although hormone application increases basal defences, expression studies and hormone analyses after nematode infection in Manikpukha did not show a clear involvement of the hormone defense pathways for SA, ET and JA. However, it seems that OsPAL1 plays a pivotal role in resistance, indicating that the phenylpropanoid pathway and its products might be key players in the incompatible interaction. Lignin measurement showed that, although basal levels are similar, Manikpukha had a significantly higher lignin content on nematode infection, whereas it was decreased in the susceptible cultivar. The results presented here show that SA, ET and JA are involved in basal defences, but the resistance of Manikpukha against D. angustus probably relies on products of the phenylpropanoid pathway. 相似文献
110.
Zamora E Handisurya A Shafti-Keramat S Borchelt D Rudow G Conant K Cox C Troncoso JC Kirnbauer R 《Journal of immunology (Baltimore, Md. : 1950)》2006,177(4):2662-2670
Immunization with amyloid-beta (Abeta) prevents the deposition of Abeta in the brain and memory deficits in transgenic mouse models of Alzheimer's disease (AD), opening the possibility for immunotherapy of AD in humans. Unfortunately, the first human trial of Abeta vaccination was complicated, in a small number of vaccinees, by cell-mediated meningoencephalitis. To develop an Abeta vaccine that lacks the potential to induce autoimmune encephalitis, we have generated papillomavirus-like particles (VLP) that display 1-9 aa of Abeta protein repetitively on the viral capsid surface (Abeta-VLP). This Abeta peptide was chosen because it contains a functional B cell epitope, but lacks known T cell epitopes. Rabbit and mouse vaccinations with Abeta-VLP were well tolerated and induced high-titer autoAb against Abeta, that inhibited effectively assembly of Abeta(1-42) peptides into neurotoxic fibrils in vitro. Following Abeta-VLP immunizations of APP/presenilin 1 transgenic mice, a model for human AD, we observed trends for reduced Abeta deposits in the brain and increased numbers of activated microglia. Furthermore, Abeta-VLP vaccinated mice also showed increased levels of Abeta in plasma, suggesting efflux from the brain into the vascular compartment. These results indicate that the Abeta-VLP vaccine induces an effective humoral immune response to Abeta and may thus form a basis to develop a safe and efficient immunotherapy for human AD. 相似文献