Examinando por Autor "Vera, M."

Mostrando 1 - 4 de 4
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    Environmental reprogramming of the expression of protein kinase CK2β subunit in fish
    (Springer, 2001) Alvarez, M.; Kausel, G.; Figueroa, J.; Vera, M.
    The dramatic segregation of the nucleolar components in winter-acclimatized carp is the most striking cellular-phenotypical feature observed during the seasonal adaptation of this fish toward the circannual changes in its habitat. Our studies also show that the carp habitat temperature and photoperiod winter conditions provoke a remarkable reduction of both rRNA transcription and the processing of their precursors. To gain knowledge on the mechanisms involved in the regulation of nucleolar activity during the seasonal adaptation process, we studied the behavior of some genes, specifically snoRNA U3 and protein kinase CK2. Consistent with the reduction in the synthesis and processing of pre-rRNA observed during the cold season, the level of CK2β expression decreases in winter when compared to that attained in summer. Similarly, in winter, liver and kidney cells contain lower levels of CK2β subunit protein compared to summer. CK2 is associated with or modifies different factors and enzymes involved in the nucleolar activity; therefore, its higher or lower content could be part of the molecular mechanisms underlying the nucleolar seasonal changes that occur during the compensatory acclimatization process.
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    Gene structure of the carp fish ribosomal protein L41: Seasonally regulated expression
    (Elsevier Science, 2002-07) Molina, A.; Corta, A.; Martin, R.; Alvarez, M.; Burzio, L.; Krauskopf, M.; Vera, M.
    The seasonal acclimatization of the carp fish demands physiological compensatory responses. The process involves profound nucleolar adjustments and remarkable changes in rRNA synthesis, which affect ribosomal biogenesis. We have documented that protein kinase CK2, whose activity is related to ribosomal protein L41 and the regulation of rRNA synthesis, was expressed in notably higher amounts in summer-acclimatized carp compared to the cold-season adapted fish. Thus, we approached the study of the functional genomics of carp L41 protein. We report the first cloning of a fish L41 gene encoding the highly conserved 25 amino acids, including approximately 1700 bp regulatory upstream region and the 3′ polyadenylation signal, plus the isolation and characterization of two different L41 cDNAs. We found a clear differential expression of L41, which follows the same pattern as protein kinase CK2β that transcribes at higher levels in the summer-acclimatized carp than it does in the winter-adapted fish.
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    Imagenología médica: Fundamentos y alcance
    (Sociedad Latinoamericana de Hipertension, 2016) Huérfano, Y.; Vera, M.; Del Mar, A.; Chacón, J.; Vera, M.; Bautista, N.; Martínez, M.S.; Rojas, J.; Bermúdez, V.; Contreras-Velásquez, J.; Graterol-Rivas, M.; Wilches-Duran, S.; Torres, M.; Prieto, C.; Siguencia, W.; Ortiz, R.; Aguirre, M.; Angarita, L.; Cerda, M.; Garicano, C.; Hernández-Ladinde, J.D.; Arias, V.; Graterol-Silva, R.; Chacín, M.; Bravo, A.
    En la actualidad es innegable la utilidad de las diversas modalidades de imagenología médica como apoyo clínico tanto en la generación de diagnósticos de un buen número de enfermedades como en la planeación de tratamientos tendientes a proporcionar una alternativa de solución a las personas que, por una u otra razón, manifiestan algún desequilibrio en su salud. Entre las modalidades imagenológicas que, frecuentemente, se utilizan en el ámbito médico se pueden mencionar: Ultrasonido (US), Resonancia Magnética (MRI), Tomografía Computarizada sencilla (CT) y multicapa (MSCT), Tomografía Computarizada por Emisión de Positrones (PET) y Tomografía Computarizada por Emisión de Fotones simples (SPECT). En este sentido, este artículo tiene como finalidad presentar una descripción ordenada, coherente y sistemática de cada una de las mencionadas modalidades y establecer la vinculación de la MSCT con situaciones clínicas íntimamente relacionadas con la anatomía cardiaca y procesos de hipertensión. La razón por la cual se hace énfasis en la MSCT es debido a que, por una parte, se cuenta con un número importante de bases de datos tanto de sujetos fisiológicos como de sujetos patológicos y, por la otra, que se tiene previsto presentar un conjunto de técnicas computacionales que serán exploradas en el desarrollo de futuras investigaciones en el contexto de aspectos anatómico-cardiológicos que influyen directa o indirectamente en la aparición, desarrollo y prevalencia de procesos hipertensivos.
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    Seasonal environmental changes regulate the expression of the histone variant macroH2A in an eurythermal fish
    (Elsevier [Former Publisher] Federation of European Biochemical Societies [Associate Organisation] Wiley [Commercial Publisher], 2005-10) Pinto, R.; Ivaldi, C.; Reyes, M.; Doyen, C.; Mietton, F.; Mongelard, F.; Alvarez, M.; Molina, A.; Dimitrov, S.; Krauskopf, M.; Vera, M.; Bouvet, P.
    Adaptation to cold and warm conditions requires dramatic change in gene expression. The acclimatization process of the common carp Cyprinus carpio L. in its natural habitat has been used to study how organisms respond to natural environmental changes. At the cellular level, adaptation to cold condition is accompanied by a dramatic alteration in nucleolar structure and a down regulation of the expression of ribosomal genes. We show that the enrichment of condensed chromatin in winter adapted cells is not correlated with an increase of the heterochromatin marker trimethyl and monomethyl K20H4. However, the expression of the tri methyl K4 H3 and of the variant histone macroH2A is significantly increased during the winter season together with a hypermethylation of CpG residues. Taking into account the properties of macroH2A toward chromatin structure and dynamics and its role in gene repression our data suggest that the increased expression of macroH2A and the hypermethylation of DNA which occurs upon winter-acclimatization plays a major role for the reorganization of chromatin structure and the regulation of gene expression during the physiological adaptation to a colder environment.