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121.
Alexander H Stegh Bryan C Barnhart Jorg Volkland Alicia Algeciras-Schimnich Ning Ke John C Reed Marcus E Peter 《The Journal of biological chemistry》2002,277(6):4351-4360
Apoptosis induction through CD95 (APO-1/Fas) critically depends on generation of active caspase-8 at the death-inducing signaling complex (DISC). Depending on the cell type, active caspase-8 either directly activates caspase-3 (type I cells) or relies on mitochondrial signal amplification (type II cells). In MCF7-Fas cells that are deficient for pro-caspase-3, even high amounts of caspase-8 produced at the DISC cannot directly activate downstream effector caspases without mitochondrial help. Overexpression of Bcl-x(L) in these cells renders them resistant to CD95-mediated apoptosis. However, activation of caspase-8 in control (vector) and Bcl-x(L) transfectants of MCF7-Fas cells proceeds with similar kinetics, resulting in a complete processing of cellular caspase-8. Most of the cytosolic caspase-8 substrates are not cleaved in the Bcl-x(L) protected cells, raising the question of how Bcl-x(L)-expressing MCF7-Fas cells survive large amounts of potentially cytotoxic caspase-8. We now demonstrate that active caspase-8 is initially generated at the DISC of both MCF7-Fas-Vec and MCF7-Fas-Bcl-x(L) cells and that the early steps of CD95 signaling such as caspase-8-dependent cleavage of DISC bound c-FLIP(L), caspase-8-dependent clustering, and internalization of CD95, as well as processing of pro-caspase-8 bound to mitochondria are very similar in both transfectants. However, events downstream of mitochondria, such as release of cytochrome c, only occur in the vector-transfected MCF7-Fas cells, and no in vivo caspase-8 activity can be detected in the Bcl-x(L)-expressing cells. Our data suggest that, in Bcl-x(L)-expressing MCF7-Fas cells, active caspase-8 is sequestered on the outer mitochondrial surface presumably by association with the protein "bifunctional apoptosis regulator" in a way that does not allow substrates to be cleaved, identifying a novel mechanism of regulation of apoptosis sensitivity by mitochondrial Bcl-x(L). 相似文献
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We consider a very simple adaptive rule that induces cooperative behavior in a large class of dilemma games. The rule has a Pavlovian flavor and can be described as win-continue, lose-reverse. It assumes no knowledge about the underlying structure of the environment (the "rules of the game") and requires very little cognitive effort. Both features make it an appealing candidate for explaining the emergence of cooperative behavior in non-human species. 相似文献
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126.
Nelson H. Caicedo Birgit Heyduck-Söller Ulrich Fischer Jorg Thöming 《Journal of applied phycology》2011,23(5):811-818
The synthesis of bioactive compounds with antimicrobial activity, excreted by marine cyanobacteria, strongly depends on their
growth conditions. Due to the wide variety of biomolecules which could show properties as growth inhibitors and their low
concentrations within the culture medium, the activity of their crude extracts also seems to be related to the extraction
method used. Using the marine filamentous cyanobacterium Geitlerinema strain Flo1, we demonstrate a systematic approach for identifying optimal culture conditions to obtain culture media extracts
with antimicrobial activity. The changes in the culture conditions, such as the addition of NaBr to the medium, cell immobilisation
in vegetable sponge pieces, or temperature, effected the production of these bioactive compounds. The crude extract, containing
middle polar molecules, obtained by extraction with Amberlite XAD-1180 had a higher antifouling activity upon a number of
bacteria and fungi than the extract obtained by extraction with Amberlite XAD-16. The lowest inhibitory concentration obtained
upon Rhodosporidium sphaerocarpum was still ten times higher than that of bis(tributyltin)oxide, but compared to zinc pyrithione, it was two times more active. 相似文献
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128.
Sheep prions with molecular properties intermediate between classical scrapie,BSE and CH1641–scrapie
Jan PM Langeveld Jorg G Jacobs Jo HF Erkens Thierry Baron Olivier Andréoletti Takahashi Yokoyama 《朊病毒》2014,8(4):296-305
Efforts to differentiate bovine spongiform encephalopathy (BSE) from scrapie in prion infected sheep have resulted in effective methods to decide about the absence of BSE. In rare instances uncertainties remain due to assumptions that BSE, classical scrapie and CH1641–a rare scrapie variant–could occur as mixtures. In field samples including those from fallen stock, triplex Western blotting analyses of variations in the molecular properties of the proteinase K resistant part of the disease‑associated form of prion protein (PrPres) represents a powerful tool for quick discrimination purposes. In this study we examined 7 deviant ovine field cases of scrapie for some typical molecular aspects of PrPres found in CH1641‑scrapie, classical scrapie and BSE. One case was most close to scrapie with respect to molecular mass of its non-glycosylated fraction and N-terminally located 12B2‑epitope content. Two cases were unlike classical scrapie but too weak to differentiate between BSE or CH1641. The other 4 cases appeared intermediate between scrapie and CH1641 with a reduced molecular mass and 12B2‑epitope content, together with the characteristic presence of a second PrPres population. The existence of these 2 PrPres populations was further confirmed through deglycosylation by PNGaseF. The findings indicate that discriminatory diagnosis between classical scrapie, CH1641 and BSE can remain inconclusive with current biochemical methods. Whether such intermediate cases represent mixtures of TSE strains should be further investigated e.g. in bioassays with rodent lines that are varying in their susceptibility or other techniques suitable for strain typing. 相似文献
129.
Long-term (70-year) monitoring of reef structure through high-resolution multidecadal aerial imagery
Newnham Tahlia J. Browne Nicola K. Bumbak Joshua Loudon Luke Wellington Harry Shedrawi George Hacker Jorg O’Leary Michael 《Coral reefs (Online)》2020,39(6):1859-1870
Coral Reefs - Here, we utilise a unique, 70-year-long (1949–2017), high-resolution historical aerial imagery dataset to track changes to coral reef structures in Bill’s Bay on the... 相似文献
130.
Knebel B Janssen OE Hahn S Jacob S Nitzgen U Haas J Muller-Wieland D Kotzka J 《Molecular biology reports》2012,39(6):6835-6842
The polycystic ovary syndrome (PCOS) is a complex endocrine-metabolic disorder consisting of reproductive disturbances associated
with all aspects of the metabolic syndrome and genetic components in the pathology of this complex disease is very likely.
Accordingly, variations in single genes might affect specific features of PCOS and thereby help to define different subgroups.
SREBP-1 or LXRα have been shown to be genetically linked to lipid metabolism or insulin sensitivity. As these are two major
aspects of the PCOS phenotype, we evaluated both genes in a cohort of 153 PCOS patients. Analyses of both genes revealed in
SREBF-1, i.e. SREBP-1a and SREBP-1c, not any variation and in the LXRα gene no novel sequence variations. Common variants
of LXRα (rs2279238:G; all:0.8658; PCOS:0.8627; controls: 0.8686 or A: all:0.13412; PCOS:0.1373; controls:0.1314; (OR (95%
CI) 0.9508 (0.4226–2.1385); rs11039155: G: all:0.8767; PCOS:0.8663; controls:0.8857 and A all:0.1233; PCOS:0.1337; controls:0.1143;
(OR (95% CI) 0.8383 (0.3618–1.9371)) were also not directly associated to PCOS. Combined analyses of both polymorphism revealed
that there was no difference of distribution between the groups. In contrast, analyses of the impact of these polymorphisms
on metabolic parameters of the syndrome indicated significant differences related to genotypes. The data indicated that rs11039155
increases metabolic risk, whereas rs2279238 has a protective effect on the overall metabolic risk. The investigation of the
PCOS group presented indicates that the combined analyses of variations in putative candidate genes allowed a genotype-phenotype
correlation for metabolic features. 相似文献