Browsing by Subject "Senescence"

Now showing 1 - 7 of 7
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    Cambios en actividad triosa-fosfato isomerasa y estudio de su posible pérdida por cloroplastos durante el envejecimiento de hojas
    (Murcia: Universidad de Murcia, Servicio de Publicaciones, 1989) Cuello Moreno, Juan; Sabater, B.; Quiles Ródenas, María José de Jesus; Facultad de Biología
    Hemos estudiado los cambios relativos de triosa-fosfato isomerasa en el citoplasma y en los cloroplastos durante el envejecimiento de las hojas primarias de cebada. Las fracciones subcelulares se aislaron por ultracentrifugación hasta equilibrio en un gradiente de densidad de sacarosa. Las actividades glucosa-6-fosfato deshidrogenasa y TIM del citoplasma disminuyeron a lo largo del envejecimiento y su pérdida era retrasada por quinetina. La actividad TIM en los cloroplastos era relativamente baja. La presencia de actividad TIM en fracciones de ultracentrifugación situadas entre las de cloroplastos y citoplasma sugirió que la actividad TIM era perdida por los cloroplastos rotos. Sin embargo, no encontramos factor estimulante de la rotura de los cloroplastos en hojas en envejecimiento.
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    CD9 expression in vascular aging and atherosclerosis
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Kim, Jae-Ryong; Cho, Joon Hyuk
    CD9 is a transmembrane glycoprotein belonging to the tetraspanin family. CD9 expression has been reported to be associated with cellular signaling, cell adhesion, cell migration, and tumor related processes. The aim of this study was to examine the immunohistochemical expression of CD9 in vascular senescence and atherosclerosis. One hundred and twenty samples of normal young arteries (obtained from individuals aged 0-60 years), 40 samples of normal old arteries (obtained from individuals aged 61-80 years), and 67 samples of atherosclerotic arteries were obtained from surgically resected specimens. Tissue microarray blocks were prepared for immunohistochemical staining. Immunohistochemical staining detected CD9 expression in 10.8% (13 of 120 samples) of normal young arteries and 30.0% (12 of 40 samples) of normal old arteries. CD9 expression was absent or mildly present in the smooth muscle cells and endothelial cells of normal arteries. Normal old arteries showed significantly higher expression of CD9 than normal young arteries (P<0.01). Atherosclerotic arteries showed moderate or strong CD9 expression (65 of 67 samples, 97.0%), which was observed in the smooth muscle cells, endothelial cells, macrophages, and atheromatous plaques. CD9 was significantly expressed in the atherosclerotic arteries compared to normal young and old arteries (P<0.01). The results suggest that CD9 expression may play an important role in the vascular senescence and pathogenesis of atherosclerosis.
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    Conservación de claveles cortados (Dianthus caryophyllus, L. cv. Arthur). II. Control del metabolismo y acción del etileno
    (Murcia: Universidad de Murcia, Servicio de Publicaciones, 1987) Serrano, M.; Riquelme, F.; Río Conesa, José Antonio del; Acosta Echevarría, Manuel; Facultad de Biología
    La senescencia de claveles cortados (Dianthus caryophyllus, L. cv. Arthur) puede ser retrasada por compuestos que inhiban la síntesis de etileno o su mecanismo de acción hormonal. Los compuestos ácido aminooxiacético (AOA) y aminoetoxivinilglicina (AVG) prolongan la longevidad de estas flores durante 4 días, comprobándose que inhiben su producción de etileno actuando a nivel de ACC-sintetasa. Compuestos como ácido cx:-aminoisobutírico (AIB), Cl2Co, galato de n-propilo, benzoato de sodio, ácido acetilsalicílico y 8-hidroxiquinoleína inhiben la actividad EFE. Sin embargo, sólo AIB y 8-hidroxiquinoleína retrasan la senescencia de los claveles, mientras que galato de n-propilo y benzoato de sodio la adelantan, Cl2Co tiene efectos fitotóxicos y el ácido acetilsalicílico no tiene prácticamente influencia en la misma. Los tratamientos más eficaces para prolongar la longevidad de los claveles son los realizados con tiosulfato de plata (STS), el cual bloquea la unión del etileno a su receptor hormonal, impidiendo la síntesis autocatalítica de esta hormona.
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    Conservación de la flor cortada de clavel (Dianthus caryophyllus, L. cv. Arthur). I. Uso de disoluciones conservadoras
    (Murcia: Universidad de Murcia, Servicio de Publicaciones, 1987) Serrano, M.; Rosauro, J.; Río Conesa, José Antonio del; Acosta Echevarría, Manuel; Facultad de Biología
    La senescencia de las flores de clavel (Dianthus caryophyllus, L. cv. Arthur) es un proceso programado genéticamente cuyas manifestaciones más aparentes son la pérdida de peso fresco de la flor, el enrollamiento de sus pétalos y la producción de etileno. Se diseñan dos disoluciones conservadoras (denominadas SB y SN) capaces, ambas, de aumentar la longevidad de estas flores cortadas, puesto que impiden la proliferación de microorganismos y mantienen un pH ácido, evitando la obstrucción del sistema vascular del tallo. La disolución SN proporciona, además, una fuente carbonada (sacarosa). Se comprueba la eficacia de estas disoluciones comparándolas con otras comerciales utilizadas para la conservación de flores cortadas.
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    Defective expression of the peroxisome regulators PPARα receptors and lysogenesis with increased cellular senescence in the venous wall of chronic venous disorder
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2021) Ortega, Miguel A; Fraile-Martínez, Oscar; Pekarek, Leonel; Alvarez-Mon, Miguel A.; Asúnsolo, Ángel; Sanchez-Trujillo, Lara; Coca, Santiago; Buján, Julia; Álvarez-Mon, Melchor; GarcíaHonduvilla, Natalio; Sain, Felipe
    The pathogenesis of chronic venous disorder (CVeD) remains partially understood. A marked wall remodeling has been shown with potential accelerated tissue senescence. We have investigated the expression of peroxisome proliferator-activated receptor (PPAR) isoforms transcription factor EB (TFEB) as regulatory molecules of cellular homeostasis and makers of peroxisomal and lysosomal biogenesis. We have also quantified p16 expression as a cellular senescence marker. In specimens of maior safena vein from 35 CVeD and 27 healthy venous controls (HV), we studied the expression of PPAR-α, PPAR-β/δ, PPAR-γ, TFEB and p16 by RT-qPCR and immunohistochemical techniques. We have demonstrated a reduced gene and protein expression of the PPAR-α and PPAR-β/δ isoform as well as that of TFEB in the venous wall of CVeD patients, suggesting an altered peroxisomal and lysosomal biogenesis associated with an increased cellular senescence shown by increased p16 expression
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    Schwannomas, bening tumors with a senescent phenotype
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2014) Simonetti, S.; Serrano, C.; Hernández-Losa, J.; Bagué, S.; Orellana, R.; Valverde, C.; Lleonart, M. E.; Aizpurua, M.; Carles, J.; Ramón y Cajal, S.; Romagosa, C.
    Background: Schwannomas are benign nerve sheath tumors that only very rarely undergo malignant changes. Oncogenic-induced senescence is a defense mechanism against such malignant transformation. Different molecular pathways are involved in this process, such as RAS-RAF-MAPK. Based on the fact that the RAS-RAF-MAPK pathway is known to be activated in peripheral nerve sheath tumors, this study analyzes senescence markers in Schwannomas to demonstrate the possible role of senescence in their genesis. Methods: A retrospective immunohistochemical study was done in 39 schwannoma and 18 malignant peripheral nerve sheath tumors (MPNST). Staining for p16INK4a, Ki67, p53 and CyclinD1 was performed in all the cases. Additionally, ß-galactosidase staining was done in those cases in which frozen tissue was available (n=8). Results: Higher levels of p16INK4a (p=0.0001) and lower levels of Ki67 (p=0.0001) were found in Schwannomas. Beta-galactosidase activity was positive in 5/5 Schwannomas and negative in 3/3 MPNST. Conclusions: Our results support the senescence nature of Schwannomas and the absence of a senescence phenotype in MPNST.
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    The ARF-p53 senescence pathway in mouse and human cells
    (Murcia : F. Hernández, 2004) Wadhwa, R.; Sugahara, T.; Taira, K.; Kaul, S.C.
    Mouse and human cells have most frequently been used for studies that have led to the elucidation of various molecular pathways involved in senescence. The ARF–p53 pathway has been assigned as one of the major protagonists in these phenomena. ARF is an alternative reading frame protein encoded along with p16INK4A by the INK4a locus on human chromosome 9p21 and the corresponding locus on mouse chromosome 4. Whereas the mouse ARF (p19ARF) consists of 169 amino acids, the human ARF (p14ARF) consists of 132 amino acids, truncated at the C-terminus. Molecular studies on the regulation of ARF activity by its binding partners have revealed that mouse ARF protein, but not human ARF protein, interacts with a cytoplasmic protein, Pex19p. This interaction of mouse ARF with Pex19p results in its milder p53 activation function in mouse cells as compared to human cells and thus accounts, at least in part, for the weaker tumor surveillance and frequent immortalization of mouse cells.