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Granulosa cell-oocyte interactions: the phosphorylation of specific proteins in mouse oocytes at the germinal vesicle stage is dependent upon the differentiative state of companion somatic cells
No full textThe role of granulosa cells in the regulation of mouse ovarian oocyte metabolism
was investigated. Fully grown antral oocytes, isolated from surrounding cumulus
cells, were cultured on monolayers of preantral granulosa cells in the presence
of dbcAMP to prevent the resumption of meiosis. Under these conditions metabolic
cooperativity was established between the two cell types as early as 1 hr after
seeding. Moreover, cocultured oocytes phosphorylated two polypeptides of 74 and
21 kDa which are normally phosphorylated in follicle-enclosed growing oocytes but
not in cumulus cell-enclosed fully grown oocytes at the germinal vesicle stage.
When cocultured oocytes were allowed to resume meiosis, the 74 and 21 kDa
proteins were synthesized but no longer phosphorylated even though intercellular
coupling between the two cell types was maintained during radiolabeling. It
appears therefore: a) that the different protein kinase activity of growing and
fully grown germinal vesicle-stage mouse oocytes is related to the
differentiative state of granulosa cells, and b) that the regulation of oocyte
protein phosphorylation activity by granulosa cells is dependent on the meiotic
stage of the oocyte
Evaluation of the elevated plus-maze and open-field tests for the assessment of anxiety-related behaviours in inbred mice
No full textEffects of protein kinase C stimulation and free Ca2+ rise in mammalian egg activation.
No full textProtein phosphorylation activity, chromosome segregation, and cortical granule exocytosis (CGE) have been studied in mouse eggs activated parthenogenetically by specific PKC stimulators such as 4 beta-phorbol 12-myristate 13-acetate (PMA) and 1-oleyl-2-acetylglycerol (OAG), or by agents inducing an immediate increase in cytosolic calcium concentration ([Ca2+]i) such as ethanol and Ca-ionophore A23187. When protein phosphorylation activity of mouse eggs was analyzed 10 min after different activation treatments, the phosphorylation of a 32 kDa polypeptide was a feature common to all different parthenogenetic agents used. The appearance of such labeling was independent of an increasing [Ca2+]i, as indicated by direct measurements of 1) cytosolic Ca2+ concentration with fura-2 and 2) exogenous Ca2+ entrance into activated eggs. Emission of the second polar body was blocked in PMA-elicited parthenogenones, whereas it was apparently normal in OAG-treated eggs, unless the eggs were continuously exposed to OAG. CGE was almost immediate in ethanol-activated eggs, but in PMA-treated cells, it occurred significantly later, with a timing corresponding to that found for the appearance of sustained Ca2+ oscillations in this system. Here, we propose that in mammalian eggs 1) PKC stimulation represents an early regulatory step in egg activation; 2) this kinase activity is turned off before the second meiotic cleavage; and 3) cytosolic free Ca2+ rise is essential for CGE occurrence
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Amino acid transport systems in growing mouse oocytes.
No full textAmino acid transport systems have been studied in isolated mouse oocytes
throughout oogenesis. While these cells were lacking the A-transport system of
Ehrlich cell (Christensen, 1975), they were found to be provided with the L- and
ASC-systems of Ehrlich cell (Christensen, 1975). Since, in contrast to the
A-system, the L- and ASC-systems mainly work by exchanging internal and external
amino acids, we propose that their main function is to actively maintain the
appropriate internal balance between different amino acids within the growing
oocyte
Somatic cell-oocyte interactions in mouse oogenesis: stage-specific regulation of mouse oocyte protein phosphorylation by granulosa cells
No full text
Stage-dependent modifications of amino acid uptake by antral and metaphase II mouse oocytes.
No full textModifications of leucine transport system of mouse oocytes have been studied
throughout Graafian follicle development and oocyte maturation. In contrast to
sheep oocytes (Moor and Smith, 1979), in the mouse kinetic constants and efflux
rate of leucine transport system did not vary in diestrus, proestrus, and
metaphase II (met II) oocytes. However, kinetics of leucine equilibration in
proestrus and met II oocytes was significantly slower than that found in diestrus
cells, and this may reflect a decreased availability of internal amino acids for
exchange
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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