Examinando por Autor "González, C."
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Ítem Extracellular cysteine in connexins: Role as redox sensors(FRONTIERS MEDIA, 2016-01) Retamal, M.A.; García, I.E.; Pinto, B.I.; Pupo, A.; Báez, D.; Stehberg, J.; Del Rio, R.; González, C.Connexin-based channels comprise hemichannels and gap junction channels. The opening of hemichannels allow for the flux of ions and molecules from the extracellular space into the cell and vice versa. Similarly, the opening of gap junction channels permits the diffusional exchange of ions and molecules between the cytoplasm and contacting cells. The controlled opening of hemichannels has been associated with several physiological cellular processes; thereby unregulated hemichannel activity may induce loss of cellular homeostasis and cell death. Hemichannel activity can be regulated through several mechanisms, such as phosphorylation, divalent cations and changes in membrane potential. Additionally, it was recently postulated that redox molecules could modify hemichannels properties in vitro. However, the molecular mechanism by which redox molecules interact with hemichannels is poorly understood. In this work, we discuss the current knowledge on connexin redox regulation and we propose the hypothesis that extracellular cysteines could be important for sensing changes in redox potential. Future studies on this topic will offer new insight into hemichannel function, thereby expanding the understanding of the contribution of hemichannels to disease progression.Ítem Improved ontology for eukaryotic single-exon coding sequences in biological databases(Oxford University Press, 2018-01) Jorquera, R.; González, C.; Clausen, P.; Petersen, B.; Holmes, D.S.Efficient extraction of knowledge from biological data requires the development of structured vocabularies to unambiguously define biological terms. This paper proposes descriptions and definitions to disambiguate the term 'single-exon gene'. Eukaryotic Single-Exon Genes (SEGs) have been defined as genes that do not have introns in their protein coding sequences. They have been studied not only to determine their origin and evolution but also because their expression has been linked to several types of human cancer and neurological/developmental disorders and many exhibit tissue-specific transcription. Unfortunately, the term 'SEGs' is rife with ambiguity, leading to biological misinterpretations. In the classic definition, no distinction is made between SEGs that harbor introns in their untranslated regions (UTRs) versus those without. This distinction is important to make because the presence of introns in UTRs affects transcriptional regulation and post-transcriptional processing of the mRNA. In addition, recent whole-transcriptome shotgun sequencing has led to the discovery of many examples of single-exon mRNAs that arise from alternative splicing of multi-exon genes, these single-exon isoforms are being confused with SEGs despite their clearly different origin. The increasing expansion of RNA-seq datasets makes it imperative to distinguish the different SEG types before annotation errors become indelibly propagated in biological databases. This paper develops a structured vocabulary for their disambiguation, allowing a major reassessment of their evolutionary trajectories, regulation, RNA processing and transport, and provides the opportunity to improve the detection of gene associations with disorders including cancers, neurological and developmental diseases. © The Author(s) 2018. Published by Oxford University Press.Ítem Pannexin-1 expression in tumor cells correlates with colon cancer progression and survival(Elsevier, 2024-08) Fierro-Arenas, A.; Landskron, G.; Camhi-Vainroj, I.; Basterrechea, B.; Parada-Venegas, D.; Lobos-González, L.; Dubois-Camacho, K.; Araneda, C.; Romero, C.; Domínguez, A.; Vásquez, G.; López, F.; Alvarez, K.; González, C.; Hager, C.; Balboa, E.; Eugenin, E.; Hermoso, M.; De la Fuente, M.Aims Pannexin-1 (PANX1) is a hemichannel that releases ATP upon opening, initiating inflammation, cell proliferation, and migration. However, the role of PANX1 channels in colon cancer remains poorly understood, thus constituting the focus of this study. Main methods PANX1 mRNA expression was analyzed using multiple cancer databases. PANX1 protein expression and distribution were evaluated by immunohistochemistry on primary tumor tissue and non-tumor colonic mucosa from colon cancer patients. PANX1 inhibitors (probenecid or 10Panx) were used to assess colon cancer cell lines viability. To study the role of PANX1 in vivo, a subcutaneous xenograft model using HCT116 cells was performed in BALB/c NOD/SCID immunodeficient mice to evaluate tumor growth under PANX1 inhibition using probenecid. Key findings PANX1 mRNA was upregulated in colon cancer tissue compared to non-tumor colonic mucosa. Elevated PANX1 mRNA expression in tumors correlated with worse disease-free survival. PANX1 protein abundance was increased on tumor cells compared to epithelial cells in paired samples, in a cancer stage-dependent manner. In vitro and in vivo experiments indicated that blocking PANX1 reduced cell viability and tumor growth. Significance PANX1 can be used as a biomarker of colon cancer progression and blocking PANX1 channel opening could be used as a potential therapeutic strategy against this disease.Ítem Synthesis of five known brassinosteroid analogs from hyodeoxycholic acid and their activities as plant-growth regulators(MDPI, 2017-03) Durán, M.I.; González, C.; Acosta, A.; Olea, A.F.; Díaz, K.; Espinoza, L.Brassinosteroids (BRs) are plant hormones that promote growth in different plant organs and tissues. The structural requirements that these compounds should possess to exhibit this biological activity have been studied. In this work, a series of known BR analogs 5-15, were synthesized starting from hyodeoxycholic acid 4, and maintaining the alkyl side chain as cholic acid or its methyl ester. The growth-promoting effects of brassinolide (1) and synthesized analogs were evaluated by using the rice lamina inclination assay at concentrations ranging from 1 x 10(-8)-1 x 10(-6) M. Our results indicate that in this concentration range the induced bending angle of rice seedlings increases with increasing concentration of BRs. Analysis of the activities, determined at the lowest tested concentration, in terms of BR structures shows that the 2 alpha,3 alpha-dihydroxy-7-oxa-6-ketone moiety existing in brassinolide is required for the plant growing activity of these compounds, as it has been proposed by some structure-activity relationship studies. The effect of compound 8 on cell elongation was assessed by microscopy analysis, and the results indicate that the growth-promoting effect of analog 8 is mainly due to cell elongation of the adaxial sides, instead of an increase on cell number.Ítem Variación espacio-temporal en la composición del ensamble de macroalgas del intermareal rocoso de Maitencillo, Valparaíso, costa central de Chile(Universidad de Valparaiso, 2018-04) Betancourtt, C.; Zapata, J.; Latorre, N.; Anguita, C.; Castañeda, F.; Meynard, A.; Fierro, C.; Espinoza, C.; Guajardo, E.; Núñez, A.; Salas, N.; González, C.; Ramírez, M.-E.; Bulboa-Contador, C.; Contreras-Porcia, L.Records on the diversity of algae serve as a foundation for establishing management and environmental protection programs, as well as for determining new commercial uses of algae. With this context in mind, the goal of the present study was to determine the richness, coverage, and composition of the macroalgae assemblage in the intertidal zone of Maitencillo, Valparaíso, Chile over the course of 3 years (2013-2015). A total of 29 species were recorded from 3 phyla - 23 Rhodophyta; 3 Ochrophyta, of the Phaeophyceae class; and 3 Chlorophyta. Species richness presented high spatial and temporal variations, with these variations most significantly explained by intertidal zone (61%) and the seasons (31%). The highest levels of specific richness were recorded in the mid and lower intertidal zones (14 species) in spring, as well as in the lower intertidal zone (14 species) during summer. The lowest values of specific richness were recorded for the mid intertidal zone (2 species) during fall. The distinct levels of the intertidal zone also notably impacted algae assemblage, explaining 53% of variation while the seasons explained 18% of variation. The greatest coverage was recorded in the mid intertidal zone during spring, with a predominance of Mazzaella laminarioides and Ulva spp. complex. In turn, the lowest coverage was found in fall, linked with processes of sand accretion. In rocky walls, the Pyropia complex dominated. Results indicate a marked pattern of vertical and seasonal distribution in the macroalgae assemblage, as well as notably high presence of Rhodophyta species. This benthic flora description serves to update information on the diversity of representative algal species from Valparaíso Region of Chile. © 2018, Universidad de Valparaiso. All rights reserved.Ítem Vitamin D supplementation: is it safe and effective for the treatment of COVID-19?(NLM (Medline), 2022-03) Fuentes, H.; Aguilera, R.; González, C.; López, O.; Herrera, B.Leímos con interés el artículo titulado “Vitamina D y su importancia en la infección por SARS-CoV-2” (1), que a partir de un análisis realizado al trabajo denominado “Interaction between age and vitamin D deficiency in severe COVID-19 infection” (2), nos alerta sobre la importancia de la vitamina D como posible factor de riesgo y pronóstico para la COVID-19. No obstante, sobre la base de la revisión bibliográfica realizada por el autor, nos parece interesante intentar responder a la interrogante final plasmada en su escrito, referente a la seguridad y eficacia de los suplementos de vitamina D para el manejo de pacientes con COVID-19.