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排序方式: 共有625条查询结果,搜索用时 593 毫秒
41.
Gunther Zischinsky Frank Osterkamp Doerte Vossmeyer Grit Zahn Dirk Scharn Ariane Zwintscher Roland Stragies 《Bioorganic & medicinal chemistry letters》2010,20(1):65-68
Recently, a new class of selective integrin α5β1inhibitors consisting of a heterocyclic based scaffold was published. Herein the SAR and pharmacokinetic profiles of N-phenyl piperidine derivatives are described. 相似文献
42.
Ariane Germeyer Michael von Wolff Julia Jauckus Thomas Strowitzki Tanuj Sharma Anna T Grazul-Bilska 《Reproductive biology and endocrinology : RB&E》2010,8(1):67
Background
Reproductive failure, determined as recurrent spontaneous abortions (RSA) or recurrent implantation failure (RIF) in women is not well understood. Several factors, including embryo quality, and cellular and molecular changes in endometrium may contribute to the insufficient feto-maternal interaction resulting in reproductive failure. Prior clinical studies suggest an inadequate endometrial growth and development of the endometrium, leading to a lesser endometrial thickness. 相似文献43.
New insights into the unique structure of the F0F1-ATP synthase from the chlamydomonad algae Polytomella sp. and Chlamydomonas reinhardtii
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In this study, we investigate the structure of the mitochondrial F(0)F(1)-ATP synthase of the colorless alga Polytomella sp. with respect to the enzyme of its green close relative Chlamydomonas reinhardtii. It is demonstrated that several unique features of the ATP synthase in C. reinhardtii are also present in Polytomella sp. The alpha- and beta-subunits of the ATP synthase from both algae are highly unusual in that they exhibit extensions at their N- and C-terminal ends, respectively. Several subunits of the Polytomella ATP synthase in the range of 9 to 66 kD have homologs in the green alga but do not have known equivalents as yet in mitochondrial ATP synthases of mammals, plants, or fungi. The largest of these so-called ASA (ATP Synthase-Associated) subunits, ASA1, is shown to be an extrinsic protein. Short heat treatment of isolated Polytomella mitochondria unexpectedly dissociated the otherwise highly stable ATP synthase dimer of 1,600 kD into subcomplexes of 800 and 400 kD, assigned as the ATP synthase monomer and F(1)-ATPase, respectively. Whereas no ASA subunits were found in the F(1)-ATPase, all but two were present in the monomer. ASA6 (12 kD) and ASA9 (9 kD), predicted to be membrane bound, were not detected in the monomer and are thus proposed to be involved in the formation or stabilization of the enzyme. A hypothetical configuration of the Chlamydomonad dimeric ATP synthase portraying its unique features is provided to spur further research on this topic. 相似文献
44.
Activation of a dimeric metabotropic glutamate receptor by intersubunit rearrangement 总被引:1,自引:0,他引:1
Brock C Oueslati N Soler S Boudier L Rondard P Pin JP 《The Journal of biological chemistry》2007,282(45):33000-33008
Although many G protein-coupled receptors (GPCRs) can form dimers, a possible role of this phenomenon in their activation remains elusive. A recent and exciting proposal is that a dynamic intersubunit interplay may contribute to GPCR activation. Here, we examined this possibility using dimeric metabotropic glutamate receptors (mGluRs). We first developed a system to perfectly control their subunit composition and show that mGluR dimers do not form larger oligomers. We then examined an mGluR dimer containing one subunit in which the extracellular agonist-binding domain was uncoupled from the G protein-activating transmembrane domain. Despite this uncoupling in one protomer, agonist stimulation resulted in symmetric activation of either transmembrane domain in the dimer with the same efficiency. This, plus other data, can only be explained by an intersubunit rearrangement as the activation mechanism. Although well established for other types of receptors such as tyrosine kinase and guanylate cyclase receptors, this is the first clear demonstration that such a mechanism may also apply to GPCRs. 相似文献
45.
Thyroid Hormones Reorganize the Cytoskeleton of Glial Cells Through Gfap Phosphorylation and Rhoa-Dependent Mechanisms 总被引:1,自引:0,他引:1
Zamoner A Funchal C Jacques-Silva MC Gottfried C Barreto Silva FR Pessoa-Pureur R 《Cellular and molecular neurobiology》2007,27(7):845-865
Thyroid hormones (3,5,3′-triiodo-l-thyronine, T3; 3,5,3′,5′-l-tetraiodothyronine, T4; TH) play crucial roles in the growth and differentiation of the central nervous system. In this study, we investigated the
actions of TH on proliferation, viability, cell morphology, in vitro phosphorylation of glial fibrillary acidic protein (GFAP)
and actin reorganization in C6 glioma cells. We first observe that long-term exposure to TH stimulates cell proliferation
without induce cell death. We also demonstrate that after 3, 6, 12, 18, and 24 h treatment with TH, C6 cells and cortical
astrocytes show a process-bearing shape. Furthermore, immunocytochemistry with anti-actin and anti-GFAP antibodies reveals
that TH induces reorganization of actin and GFAP cytoskeleton. We also observe an increased in vitro 32P incorporation into GFAP recovered into the high-salt Triton insoluble cytoskeletal fraction after 3 and 24 h exposure to
5×10−8 and 10−6 M T3, and only after 24 h exposure to 10−9 M T4. These results show a T3 action on the phosphorylating system associated to GFAP and suggest a T3-independent effect of T4 on this cytoskeletal protein. In addition, C6 cells and astrocytes treated with lysophosphatidic acid, an upstream activator
of the RhoA GTPase pathway, totally prevented the morphological alterations induced by TH, indicating that this effect could
be mediated by the RhoA signaling pathway. Considering that IF network can be regulated by phosphorylation leading to reorganization
of IF filamentous structure and that alterations of the microfilament organization may have important implications in glial
functions, the effects of TH on glial cell cytoskeleton could be implicated in essential neural events such as brain development. 相似文献
46.
Boudier C Bousquet JA Schauinger S Michels B Bieth JG 《Archives of biochemistry and biophysics》2007,466(2):155-163
The inhibitory activity of the serpins alpha(1)-proteinase inhibitor, alpha(1)-antichymotrypsin, alpha(2)-antiplasmin, antithrombin and C(1)-esterase inactivator is rapidly lost at pH 3 but slowly recovers at pH 7.4 with variable first-order rates (t(1/2)=1.4-19.2 min). All except alpha(1)-antichymotrypsin undergo a variation in intrinsic fluorescence intensity upon acidification (midpoint ca. 4.5) with a slow bi-exponential return to the initial intensity at pH 7.4 (mean t(1/2)=2.3-23 min). No correlation was found between the time of fluorescence recovery and that of reactivation. The acid-treated serpins are proteolyzed at neutral pH by their target proteinases. alpha(1)-Proteinase inhibitor was studied in more detail. Its acidification at pH 3 has a mild effect on its secondary structure, strongly disorders its tertiary structure, changes the microenvironment of Cys(232) and causes a very fast change in ellipticity at 225 nm (t(1/2)=1.6s). Neutralization of the acid-treated alpha(1)-proteinase inhibitor is an exothermic phenomenon. It leads to a much faster recovery of activity (t(1/2)=4+/-1 min) than of fluorescence intensity (t(1/2)=23+/-19 min), ellipticity (t(1/2)=32+/-4 min) and change in total energy, indicating that the inhibitory activity of alpha(1)-proteinase inhibitor does not require a fully native structure. 相似文献
47.
48.
Cédric MessaoudiI Thomas Boudier Carlos Oscar Sanchez Sorzano Sergio Marco 《BMC bioinformatics》2007,8(1):288
Background
Transmission electron tomography is an increasingly common three-dimensional electron microscopy approach that can provide new insights into the structure of subcellular components. Transmission electron tomography fills the gap between high resolution structural methods (X-ray diffraction or nuclear magnetic resonance) and optical microscopy. We developed new software for transmission electron tomography, TomoJ. TomoJ is a plug-in for the now standard image analysis and processing software for optical microscopy, ImageJ. 相似文献49.
Marion Nicolaus Kimberley J. Mathot Yimen G. Araya-Ajoy Ariane Mutzel Jan J. Wijmenga Bart Kempenaers Niels J. Dingemanse 《Proceedings. Biological sciences / The Royal Society》2015,282(1799)
A number of studies have suggested that avian brood size is individually optimized. Yet, optimal reproductive decisions likely vary owing to among-individual differences in environmental sensitivity. Specifically, ‘proactive’ individuals who do not track environmental changes may be less able to produce optimal brood sizes than ‘reactive’ individuals who have more precise local environmental knowledge. To test this, we quantified exploratory behaviour (a proxy for proactivity) in a great tit (Parus major) population, manipulated brood sizes (reduced, control, enlarged) and evaluated whether individuals of dissimilar coping style differed in their level of optimization. If reactive females behaved optimally, any deviation from their original brood size should lower fitness, whereas this should not be the case for proactive females. Reactive females indeed performed best at their natural brood size, whereas proactive females performed best when raising an enlarged brood. These findings imply that proactive females produced sub-optimal brood sizes. We speculate that proactive females might (i) take decisions based on biased perception of their environment, (ii) face energetic constraints in offspring production and/or (iii) be more willing to invest into current reproduction when given the option. Our findings provide experimental evidence for coping style-related differences in optimal reproductive decisions and life-history strategies. 相似文献
50.