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71.
IKKalpha controls formation of the epidermis independently of NF-kappaB 总被引:16,自引:0,他引:16
The IKKalpha and IKKbeta catalytic subunits of IkappaB kinase (IKK) share 51% amino-acid identity and similar biochemical activities: they both phosphorylate IkappaB proteins at serines that trigger their degradation. IKKalpha and IKKbeta differ, however, in their physiological functions. IKKbeta and the IKKgamma/NEMO regulatory subunit are required for activating NF-kappaB by pro-inflammatory stimuli and preventing apoptosis induced by tumour necrosis factor-alpha (refs 5,6,7,8,9,10,11). IKKalpha is dispensable for these functions, but is essential for developing the epidermis and its derivatives. The mammalian epidermis is composed of the basal, spinous, granular and cornified layers. Only basal keratinocytes can proliferate and give rise to differentiated derivatives, which on full maturation undergo enucleation to generate the cornified layer. Curiously, keratinocyte-specific inhibition of NF-kappaB, as in Ikkalpha-/- mice, results in epidermal thickening but does not block terminal differentiation. It has been proposed that the epidermal defect in Ikkalpha-/- mice may be due to the failed activation of NF-kappaB. Here we show that the unique function of IKKalpha in control of keratinocyte differentiation is not exerted through its IkappaB kinase activity or through NF-kappaB. Instead, IKKalpha controls production of a soluble factor that induces keratinocyte differentiation. 相似文献
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Karin?BreuEmail author Christopher?Hemingway 《Systemic Practice and Action Research》2005,18(5):437-455
This paper reflects on our experiences with researcher–practitioner partnering within an industry-funded Participatory Action
Research (PAR) project. We find that the nature of partnering in our industry-funded engagement differs from that of traditional,
non-industry funded PAR research. The distribution of power on the industry-funded academic-practitioner research team, whilst
fairly equitable at the outset of the project, shifted in favour of the practitioner partners with the progressive spillover
of credibility and knowledge from the academic to practitioner partners during the course of the engagement. Adhering to recommendations
for academic-practitioner research teams, in our experience, does not guarantee successful partnering according to PAR due
to the spillover problem. As the academic partners' power base erodes, the discretion to preserve the integrity of the PAR
method is increasingly placed in the hands of the practitioner partners. 相似文献
74.
Karin Reich 《Archive for History of Exact Sciences》1992,44(1):77-105
Zusammenfassung Der Riemannschen Geometrie fehlte lange Zeit ein zentraler Begriff, nämlich der des Parallelismus. Als Einstein 1916 seiner allgemeinen Relativitätstheorie die Riemannsche Geometrie in Form des damaligen Tensorkalküls (Ricci-Kalkül) zugrunde legte, war dieser ein rein formaler Kalkül ohne geometrische Interpretationen. Diesen Mangel an Geometrie behob die Einführung der Parallelverschiebung, die darüber hinaus auch eine anschaulichere, geometrische Erklärung des Krümmungstensors ermöglichte.Ausgehend von der Levi-Civitaschen Parallelverschiebung schuf Weyl 1918 den für die zukünftige Entwicklung so bedeutenden Begriff des affinen Zusammenhangs, den Schouten 1922 zum Übertragungsprinzip erweiterte. Aus den alten Christoffelsymbolen wurden die neuen , die in Zukunft sowohl in der Relativitätstheorie (Feldtheorie) als auch in der Differentialgeometrie eine fundamentale Rolle spielten. Aus der Differentialgeometrie wurden die (verschiedenen Arten von) Differentialgeometrien, die durch die vorgegebenen Übertragungen definiert waren.Zum 50. Todestag von Tullio Levi-Civita (29. 3. 1873–20. 12. 1941) 相似文献
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M. Maes W. Stevens S. Scharpe E. Bosmans F. De Meyer P. D'Hondt D. Peeters P. Thompson P. Cosyns L. De Clerck C. Bridts H. Neels A. Wauters W. Cooreman 《Cellular and molecular life sciences : CMLS》1994,50(9):821-829
This study has been carried out in order to investigate seasonal variation in peripheral blood immune cells, such as leukocytes, monocytes, neutrophils, lymphocytes, CD3+ T, CD4+ T, CD8+ t, CD25+ T, CD20+ B, and serum interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R) and sIL-2R levels in normal volunteers. Toward this end, 26 normal volunteers (13 men, 13 women) had monthly blood samplings during one calendar year for peripheral blood count, flow cytometric enumeration of peripheral leukocyte subsets and immunoassays of IL-6, sIL-6R and sIL-2R. It was found that most of the immune variables change rhythmically during the seasons as a group phenomenon. Statistically significant yearly variations with seasonal rhythms, i.e. annual rhythms or harmonics, such as semiannual, tetramensual and trimensual rhythms, were found in the number of leukocytes, neutrophils, monocytes, lymphocytes, CD4+ T, CD8+ T, CD25+ T, CD20+ B cells, in the CD4+/CD8+ ratio, and serum IL-6 and sIL-6R levels. It is concluded that the immune system is characterized by a multifrequency time-structure with significant high-amplitude yearly variations in the number of some peripheral blood leukocyte subsets. 相似文献
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Karin Pointner 《Journal of Natural History》2017,51(37-38):2283-2330
Quantitative sampling during the POS397 GroMet expedition in 2010 allowed analysis of the community structure of Zosimeidae on the Great Meteor Seamount (GMS) plateau. Twelve species of Zosime Boeck, 1873 were identified; 11 were recorded in the middle, nine in the northern, and 10 in the southern region. Similarity and diversity analyses showed no differences in community structure between these regions. The community seemed unaffected by geographical features; similarities between regions could reflect the uniform sediment structure and the complex water current system. Zosime can be characterised as monophyletic, due to the apomorphic one-segmented endopod of the mandible, armed with at most four setae. Two new species are described. Zosime carsteni sp. nov. (incrassata group) is defined by blunt spinules on the outer spines of exopods 1–3 of pereiopods 2–4 and the spinose nature of the innermost distal element of endopod 3 of pereiopods 1–4. Zosime eliasi sp. nov. (typica group) is defined by a flexible outer seta on the maxillipedal endopod. As both species bear an eight-segmented antennule (most plesiomorphic condition known so far), the recently erected anneae group is included into the typica group. An updated key of Zosime at the species level is given.
www.zoobank.org/urn:lsid:zoobank.org:pub:0BA28922-C575-4AAD-AD64-FDDBA22C34CC 相似文献
80.
Sagane Y Hosp J Zech K Thompson EM 《Cellular and molecular life sciences : CMLS》2011,68(9):1611-1622
Oriented cellulose deposition is critical to plant patterning and models suggest microtubules constrain cellulose synthase
movements through the plasma membrane. Though widespread in plants, urochordates are the only animals that synthesize cellulose.
We characterized the distinctive cellulose microfibril scaffold of the larvacean house and its interaction with house structural
proteins (oikosins). Targeted disruption of cytoskeletal elements, secretory pathways, and plasma membrane organization, suggested
a working model for templating extracellular cellulose microfibrils from animal cells that shows both convergence and differences
to plant models. Specialized cortical F-actin arrays template microfibril orientation and glycosylphosphatidylinositol-anchored
proteins in lipid rafts may act as scaffolding proteins in microfibril elongation. Microtubules deliver and maintain cellulose
synthase complexes to specific cell membrane sites rather than orienting their movement through the membrane. Oikosins are
incorporated into house compartments directly above their corresponding cellular field of expression and interact with the
cellulose scaffold to a variable extent. 相似文献