排序方式: 共有32条查询结果,搜索用时 0 毫秒
21.
Bub A Watzl B Blockhaus M Briviba K Liegibel U Müller H Pool-Zobel BL Rechkemmer G 《The Journal of nutritional biochemistry》2003,14(2):90-98
Polyphenolic compounds exert a variety of physiological effects in vitro including antioxidative, immunomodulatory and antigenotoxic effects. In a randomized crossover study in healthy men on a low-polyphenol diet, we determined the effects of 2 polyphenol-rich juices (330 ml/d) supplemented for 2 weeks on bioavailability of polyphenols, markers of antioxidative and immune status, and reduction of DNA damage. Juices provided 236 mg (A) and 226 mg (B) polyphenols with cyanidin glycosides (A) and epigallocatechin gallate (B) as major polyphenolic ingredients. There was no accumulation of plasma polyphenols after two weeks of juice supplementation. In contrast, plasma malondialdehyde decreased with time during juice interventions. Moreover, juice consumption also increased lymphocyte proliferative responsiveness, with no difference between the two juices. Interleukin-2 secretion by activated lymphocytes and the lytic activity of natural killer cells were significantly increased by both juices. Juice intervention had no effect on single DNA strand breaks, but significantly reduced oxidative DNA damage in lymphocytes. A time-delay was observed between the intake of fruit juice and the reduction of oxidative DNA damage and the increase in interleukin-2 secretion. We conclude that consumption of either juice enhanced antioxidant status, reduced oxidative DNA damage and stimulated immune cell functions. However, fruit juice consumption for 2 weeks did not result in elevated plasma polyphenols in subjects after overnight fasting. Further studies should focus on the time-delay between juice intake and changes in measured physiological functions, as well as on active polyphenolic metabolites mediating the observed effects. 相似文献
22.
Karlis Abele 《Protoplasma》1930,10(1):550-567
Zusammenfassung Die Nukleolarsubstanz wird bei der Karyokinese in gleichen Mengen auf beide Tochterzellen verteilt, infolgedessen sind die Nukleolen oder Nukleolensätze beider Tochterkerne gleich groß.Die Nukleolen oder Nukleolensätze beider Tochterzellen sind untereinander in Zahl, Form und Anordnung ähnlich. Jeder Nukleolus hat seinen Partner in der anderen Tochterzelle.In der ersten Zeit nach der Kernteilung liegen die Nukleolen in einer Ebene, die der Äquatorialplatte der Kernteilungsfigur parallel ist.Die Nukleolen können verschmelzen. Es sind aber auch alte Zellen zu treffen, die eine höhere Nukleolenzahl im Kerne führen.Eine Neubildung der Nukleolen, die nicht an die Kernteilung gebunden ist, wurde nicht beobachtet. 相似文献
23.
Annika Assmann Marija Bonifačić Karlis Briviba Helmut Sies Klaus-Dieter Asmus 《Free radical research》2013,47(4):371-376
Experimental evidence is provided that selenomethionine oxide (MetSeO) is more readily reducible than its sulfur analogue, methionine sulfoxide (MetSO). Pulse radiolysis experiments reveal an efficient reaction of MetSeO with one-electron reductants, such as e-aq (k = 1.2 × 1010M-1s-1), CO·-2 (k = 5.9 × 108 M-1s-1) and (CH3)2) C·OH (k = 3.5 × 107M-1s-1), forming an intermediate selenium-nitrogen coupled zwitterionic radical with the positive charge at an intramolecularly formed Se∴ N 2σ/1σ* three-electron bond, which is characterized by an optical absorption with λmax at 375 nm, and a half-life of about 70 μs. The same transient is generated upon HO· radical-induced one-electron oxidation of selenomethionine (MetSe). This radical thus constitutes the redox intermediate between the two oxidation states, MetSeO and MetSe. Time-resolved optical data further indicate sulfur-selenium interactions between the Se∴ N transient and GSH. The Se∴ N transient appears to play a key role in the reduction of selenomethionine oxide by glutathione. 相似文献
24.
Alexander F. Keist Florentina Ferchiu Lea Sante Sebastian Frese Wilhelm Bloch Florian Kreppel Stefan Kochanek Anca Sindrilaru Sebastian Iben Josef Högel Michael Ohnmacht Lutz E. Claes Anita Ignatius Jin Ho Chung Min Jung Lee York Kamenisch Mark Berneburg Thorsten Nikolaus Kerstin E. Braunstein Anne‐Dorte Sperfeld Albert C. Ludolph Karlis Briviba Meinhard Wlaschek Lore Florin Peter Angel Karin Scharffetter‐Kochanek 《Aging cell》2011,10(5):912-912
25.
Treiber N Maity P Singh K Kohn M Keist AF Ferchiu F Sante L Frese S Bloch W Kreppel F Kochanek S Sindrilaru A Iben S Högel J Ohnmacht M Claes LE Ignatius A Chung JH Lee MJ Kamenisch Y Berneburg M Nikolaus T Braunstein K Sperfeld AD Ludolph AC Briviba K Wlaschek M Florin L Angel P Scharffetter-Kochanek K 《Aging cell》2011,10(2):239-254
The free radical theory of aging postulates that the production of mitochondrial reactive oxygen species is the major determinant of aging and lifespan. Its role in aging of the connective tissue has not yet been established, even though the incidence of aging-related disorders in connective tissue-rich organs is high, causing major disability in the elderly. We have now addressed this question experimentally by creating mice with conditional deficiency of the mitochondrial manganese superoxide dismutase in fibroblasts and other mesenchyme-derived cells of connective tissues in all organs. Here, we have shown for the first time that the connective tissue-specific lack of superoxide anion detoxification in the mitochondria results in reduced lifespan and premature onset of aging-related phenotypes such as weight loss, skin atrophy, kyphosis (curvature of the spine), osteoporosis and muscle degeneration in mutant mice. Increase in p16(INK4a) , a robust in vivo marker for fibroblast aging, may contribute to the observed phenotype. This novel model is particularly suited to decipher the underlying mechanisms and to develop hopefully novel connective tissue-specific anti-aging strategies. 相似文献
26.
Stephan W. Barth Karlis Briviba Bernhard Watzl Nicole Jäger Doris Marko Melanie Esselen Dr. 《Biotechnology journal》2010,5(3):321-327
Irinotecan is an anticancer agent that stabilizes topoisomerase I/DNA complexes. So far, no test system has been reported for directly determining irinotecan-induced stabilization of topoisomerase I/DNA complexes in organs in vivo. We adapted an ‘in vivo complexes of enzyme to DNA’ (ICE) bioassay to assess irinotecan activity in the stomach, duodenum, colon and liver of male Wistar rats after a single treatment with irinotecan (100 mg/kg body weight, intraperitoneally). This was compared to the control group receiving 0.9% sodium chloride intraperitoneally. In addition, the DNA strand breaking properties of irinotecan were measured in mucosal cells from the distal colon by single-cell gel electrophoresis (comet assay) to investigate the association of topoisomerase poisoning and DNA damage in vivo. A single dose of irinotecan significantly increased amounts of topoisomerase I covalently bound to DNA in stomach, duodenum, colon and liver. Concomitantly, the irinotecan-treated group showed significantly higher amounts of DNA strand breaks in colon mucosa cells compared to the control group. The ICE bioassay and the comet assay represent two test systems for investigating the impact of topoisomerase I poisons on DNA integrity in colon tissues of Wistar rats. 相似文献
27.
Ulrike Neumann Sandrine Louis Andrea Gille Felix Derwenskus Ulrike Schmid-Staiger Karlis Briviba Stephan C. Bischoff 《Journal of applied phycology》2018,30(5):2837-2846
The microalgae Phaeodactylum tricornutum (PT) is known for its high content of omega-3 fatty acids, which are known to attenuate inflammation. Additionally, this microalga contains other nutrients such as carbohydrates, vitamins, proteins, and carotenoids and therefore could be of interest for animal and human nutrition. Here, we investigated the effects of hexane, ethanolic, and aqueous extracts on lipopolysaccharide (LPS)-stimulated human peripheral blood mononuclear cells (PBMCs) and on the murine macrophage cell line RAW 264.7. Further, the cytotoxicity of the extracts was studied using the MTT assay. The production of pro-inflammatory cytokines was significantly inhibited by the ethanolic and aqueous P. tricornutum extracts but not by the hexane extract. Both at the mRNA and at the protein levels, the aqueous extract inhibited LPS-induced IL-6, IL-1β, TNFα, and COX-2 expression and release by up to 96% (mRNA) and 79% (protein) in a dose-dependent manner. Compared to the aqueous extract, the ethanolic extract was less effective in cytokine inhibition. The production of nitric oxide in RAW 264.7 cells was significantly reduced by all extracts. We showed that the anti-inflammatory effect of P. tricornutum is exerted through inhibition of nuclear factor-κB activation and dependent on the mitogen-activated protein (MAP) kinase pathway. Our data indicate anti-inflammatory effects of the aqueous P. tricornutum extract and provide a basis information on the safety and potential health benefits of P. tricornutum usage for future animal and human nutrition. 相似文献
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29.
Thermal-alkaline solubilization of waste activated sludge as a pre-treatment stage for anaerobic digestion 总被引:17,自引:0,他引:17
This work studied the hydrolysis kinetics and the solubilization of waste activated sludge under a medium range temperature (50-90 degrees C) and pH in the alkaline region (8-11), as a pretreatment stage for anaerobic digestion. The hydrolysis rate for the solubilization of volatile suspended solids (VSS) followed a first-order rate. A linear polynomial hydrolysis model was derived from the experimental results leading to a satisfactory correlation between the hydrolysis rate coefficient, pH, and temperature. At pH 11 and a temperature of 90 degrees C the concentration of the VSS was 6.82%, the VSS reduction reached 45% within ten hours and at the same time the soluble COD was 70.000 mg/l and the total efficiency for methane production 0.28 l of CH4 per g of VSS loading. 相似文献
30.
McKellar RC Wolfe AP Muehlenbachs K Tappert R Engel MS Cheng T Sánchez-Azofeifa GA 《Proceedings. Biological sciences / The Royal Society》2011,278(1722):3219-3224
Despite centuries of research addressing amber and its various inclusions, relatively little is known about the specific events having stimulated the production of geologically relevant volumes of plant resin, ultimately yielding amber deposits. Although numerous hypotheses have invoked the role of insects, to date these have proven difficult to test. Here, we use the current mountain pine beetle outbreak in western Canada as an analogy for the effects of infestation on the stable isotopic composition of carbon in resins. We show that infestation results in a rapid (approx. 1 year) (13)C enrichment of fresh lodgepole pine resins, in a pattern directly comparable with that observed in resins collected from uninfested trees subjected to water stress. Furthermore, resin isotopic values are shown to track both the progression of infestation and instances of recovery. These findings can be extended to fossil resins, including Miocene amber from the Dominican Republic and Late Cretaceous New Jersey amber, revealing similar carbon-isotopic patterns between visually clean ambers and those associated with the attack of wood-boring insects. Plant exudate δ(13)C values constitute a sensitive monitor of ecological stress in both modern and ancient forest ecosystems, and provide considerable insight concerning the genesis of amber in the geological record. 相似文献