923 research outputs found

    The chromosomal passenger complex and the spindle assembly checkpoint: kinetochore-microtubule error correction and beyond

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    During mitosis, correct bipolar chromosome attachment to the mitotic spindle is an essential prerequisite for the equal segregation of chromosomes. The spindle assembly checkpoint can prevent chromosome segregation as long as not all chromosome pairs have obtained bipolar attachment to the spindle. The chromosomal passenger complex plays a crucial role during chromosome alignment by correcting faulty chromosome-spindle interactions (e.g. attachments that do not generate tension). In the process of doing so, the chromosomal passenger complex generates unattached chromosomes, a specific situation that is known to promote checkpoint activity. However, several studies have implicated an additional, more direct role for the chromosomal passenger complex in enforcing the mitotic arrest imposed by the spindle assembly checkpoint. In this review, we discuss the different roles played by the chromosomal passenger complex in ensuring proper mitotic checkpoint function. Additionally, we discuss the possibility that besides monitoring the presence of unattached kinetochores, the spindle assembly checkpoint may also be capable of responding to chromosome-microtubule interactions that do not generate tension and we propose experimental set-ups to study this

    A stochastic movement simulator improves estimates of landscape connectivity

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    Acknowledgments This publication issued from the project TenLamas funded by the French Ministère de l'Energie, de l'Ecologie, du Développement Durable et de la Mer through the EU FP6 BiodivERsA Eranet; by the Agence Nationale de la Recherche (ANR) through the open call INDHET and 6th extinction MOBIGEN to V. M. Stevens, M. Baguette, and A. Coulon, and young researcher GEMS (ANR-13-JSV7-0010-01) to V. M. Stevens and M. Baguette; and by a VLIR-VLADOC scholarship awarded to J. Aben. L. Lens, J. Aben, D. Strubbe, and E. Matthysen are grateful to the Research Foundation Flanders (FWO) for financial support of fieldwork and genetic analysis (grant G.0308.13). V. M. Stevens and M. Baguette are members of the “Laboratoire d'Excellence” (LABEX) entitled TULIP (ANR-10-LABX-41). J. M. J. Travis and S. C. F. Palmer also acknowledge the support of NERC. A. Coulon and J. Aben contributed equally to the work.Peer reviewedPublisher PD

    Estudo Galenico de Formas Plásticas (Gel E Creme) Do Extrato Bruto De “Maca”, Lepidium Peruvianum Chacon Sp. Nov.

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    Las infecciones del tracto genital son la causa más frecuente de consulta ginecológica (50-70% de las quejas). Se cree que todas las mujeres sexualmente activas ya han tenido al menos un episodio de vaginosis bacteriana y / o vulvovaginitis. El aumento de la resistencia de las bacterias a los antibióticos convencionales ha estimulado intensos esfuerzos para desarrollar nuevos agentes antimicrobianos eficaces contra estas bacterias y hongos. El objetivo de este estudio es realizar la producción de formas farmacéuticas plásticas de acción tópica dermatológica y vaginal a partir del extracto seco del hipocotiledón, de Lepidium peruvianum CHACON sp. Nov. = Lepidium meyenii WALP., Popularmente conocida como MACA; esta es una planta herbácea, bienal o anual; distribuida básicamente en los Andes Centrales del Perú, en altitudes que van desde 3.500 hasta 4.500 metros sobre el nivel del mar. Inicialmente se hizo la identificación botánica y la obtención de extracto acuoso. Se realizó la investigación de toxicidad de la planta; a través de la prueba de toxicidad aguda en ratones con el extracto bruto, realizado por vía intraperitoneal y por vía oral, la toxicidad se probó hasta una dosis de 4.500 mg / kg; y posteriormente se verificó la acción frente a hongos y bacterias patógenas, comprobando si la acción sobre hongos. Los ensayos farmacotécnicos revelaron que el extracto se incorpora perfectamente a las formulaciones elegidas. La determinación de las características físicoquímicas de los productos acabados mostró que la manipulación no altera cualitativa ni cuantitativamente el extracto. Los estudios preliminares indican que las perspectivas de su utilización en las Industrias, Cosmética y de Medicamentos son óptimas, pues la utilización de estas nuevas formulaciones conduce a una disminución del uso de métodos convencionales, que no raramente acarrean acciones indeseables al organismo humanoTesi

    The anti-apoptotic factor Bcl-2 can functionally substitute for the B cell survival but not for the marginal zone B cell differentiation activity of BAFF.

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    The TNF family ligand B cell-activating factor (BAFF, BLyS, TALL-1) is an essential factor for B cell development. BAFF binds to three receptors, BAFF-R, transmembrane activator and CAML interactor (TACI), and B cell maturation antigen (BCMA), but only BAFF-R is required for successful survival and maturation of splenic B cells. To test whether the effect of BAFF is due to the up-regulation of anti-apoptotic factors, TACI-Ig-transgenic mice, in which BAFF function is inhibited, were crossed with transgenic mice expressing FLICE-inhibitory protein (FLIP) or Bcl-2 in the B cell compartment. FLIP expression did not rescue B cells, while enforced Bcl-2 expression restored peripheral B cells and the ability to mount T-dependent antibody responses. However, many B cells retained immaturity markers and failed to express normal amounts of CD21. Marginal zone B cells were not restored and the T-independent IgG3, but not IgM, response was impaired in the TACI-IgxBcl-2 mice. These results suggest that BAFF is required not only to inhibit apoptosis of maturating B cells, but also to promote differentiation events, in particular those leading to the generation of marginal zone B cells

    Alpha-decay Rates of Yb and Gd in Solar Neutrino Detectors

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    The α\alpha-decay rates for the nuclides 168,170,171,172,173,174,176^{168,170,171,172,173,174,176}Yb and 148,150,152,154^{148,150,152,154}Gd have been estimated from transmission probabilities in a systematic α\alpha-nucleus potential and from an improved fit to α\alpha-decay rates in the rare-earth mass region. Whereas α{\alpha}-decay of 152^{152}Gd in natural gadolinium is a severe obstacle for the use of gadolinium as a low-energy solar-neutrino detector, we show that α{\alpha}-decay does not contribute significantly to the background in a ytterbium detector. An extremely long α{\alpha}-decay lifetime of 168^{168}Yb is obtained from calculation, which may be close to the sensitivity limit in a low-background solar neutrino detector.Comment: 12 pages, 1 figure; An author name was correcte
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