1,699 research outputs found
Estradiol-induced mitogen-activated protein kinase (extracellular signal-regulated kinase 1 and 2) activity in the frog (Rana esculenta) testis.
No full textSeveral lines of evidence support a key role of estradiol-17beta (E(2)) in male fertility. We have used a non-mammalian vertebrate model, the frog Rana esculenta, to investigate the regulation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) activity in the testis during the annual sexual cycle and to study whether E(2 )exerts a role in spermatogenesis through the regulation of ERK1/2 activity. ERK1/2 proteins are present in the cytoplasm and nucleus of the primary and secondary spermatogonia (SPG), and in the nucleus of primary spermatocytes. The annual E(2) profile shows a progressive increase during active spermatogenesis with a peak in the month of June. In parallel, ERK1/2 are highly phosphorylated during the period of active spermatogenesis (from April to July) compared with the regressive period (September/October) and winter stasis (from November to March). E(2) treatment induces the proliferation of primary SPG, possibly via the activation of ERK1/2, and this effect is counteracted by the anti-estrogen ICI 182-780
Thyrotropin stimulates transcription from the ferritin heavy chain promoter
No full textThyrotropin (TSH) is the primary hormone regulating the activity of the thyroid gland. We have recently shown that TSH stimulates H-ferritin mRNA levels in rat thyroid. Ferritin plays a key role in determining the intracellular fate of iron. The induction of ferritin synthesis by iron in liver is regulated both at transcriptional and translational levels. Here we present evidence that the mechanisms by which TSH regulates the mRNA levels are mediated by a diffusible product acting in trans on its own promoter. In fact, the H-ferritin promoter mediates increased CAT activity in response to hormone induction. Our results identify transcription as an important regulatory step of TSH action. They suggest that TSH induces expression of the ferritin gene, and that continuous protein synthesis is required to maintain basal ferritin gene expression in the absence of hormone
Effect of cytidine analogs on cell growth and differentiation on a human neuroblastoma line.
No full textThe cytidine analog 5-AZA-2'-deoxycytidine (5-AZA-CdR) has been demonstrated to induce cellular differentiation; on the other hand, induction of differentiation has been suggested as a possible form of therapy for leukemic cells. We have evaluated the possibility that the neuroblastoma malignant tumor growth could be controlled by treatment that promotes the differentiation of immature tumor cells. We have previously reported on differentiation of murine neuroblastoma cells (41A3) treated with 5-AZA-CdR. In this paper, we describe the effect of 5-AZA-CdR on human neuroblastoma cell line CHP-100. The drug-treated cells show some degree of differentiation, demonstrated by morphological and biochemical markers. A significant DNA hypomethylation and partial inhibition of DNA synthesis and cell proliferation is also observed. This effect is more stable than that caused by another cytidine analog, Cytosine-beta-D-Arabinofuranoside (ARA-C)
Globalization of Distinguished Supercuspidal Representations of GL(n)
No full textAn irreducible supercuspidal representation of = GL(n, ), where is a nonarchimedean local field of characteristic zero, is said to be “distinguished” by a subgroup of and a quasicharacter of if Hom(, ) ≠ 0. There is a suitable global analogue of this notion for an irreducible, automorphic, cuspidal representation associated to GL(n). Under certain general hypotheses, it is shown in this paper that every distinguished, irreducible, supercuspidal representation may be realized as a local component of a distinguished, irreducible automorphic, cuspidal representation. Applications to the theory of distinguished supercuspidal representations are provided
Restriction of Representations of GL (n + 1, ℂ) to GL (n, ℂ) and Action of the Lie Overalgebra
No full textConsider a restriction of an irreducible finite dimensional holomorphic representation of GL(n+1,C) to the subgroup GL(n,C). We write explicitly formulas for generators of the Lie algebra gl(n+1) in the direct sum of representations of GL(n,C). Nontrivial generators act as differential-difference operators, the differential part has order n − 1, the difference part acts on the space of parameters (highest weights) of representations. We also formulate a conjecture about unitary principal series of GL(n,C).© The Author(s) 201
The Balanced Voronoi Formulas for
No full textAbstract
In this article, we show how the Voronoi summation formula of [13] can be rewritten to incorporate hyper-Kloosterman sums of various dimensions on both sides. This generalizes a formula for with ordinary Kloosterman sums on both sides that was used in [1] to prove nonvanishing of GL(4) -functions by GL(2)-twists, and later by the second-named author in [16].</jats:p
Bethe Vectors for Composite Models with gl(2|1) and gl(1|2) Supersymmetry
No full textSupersymmetric composite generalized quantum integrable models solvable by the algebraic Bethe ansatz are studied. Using a coproduct in the bialgebra of monodromy matrix elements and their action on Bethe vectors, formulas for Bethe vectors in the composite models with supersymmetry based on the super-Yangians Y[gl(2|1)] and Y[gl(1|2)] are derived.The author wants to express his gratitude to N.A. Slavnov for the proposal to investigate this
topic and discussions. He thanks also to S. Pakuliak for discussions and to A.P. Isaev and
C. Burd´ık for their support. The work of the author has been supported by the Grant Agency ˇ
of the Czech Technical University in Prague, grant No. SGS15/215/OHK4/3T/14, and by the
Grant of the Plenipotentiary of the Czech Republic at JINR, Dubna
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