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| Registros recuperados: 992 | |
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| HIDALGO,CECILIA; ARACENA,PAULA; SANCHEZ,GINA; DONOSO,PAULINA. |
| In skeletal and cardiac muscle cells, specific isoforms of the Ryanodine receptor channels mediate Ca2+ release from the sarcoplasmic reticulum. These channels are highly susceptible to redox modifications, which regulate channel activity. In this work, we studied the effects of Ca2+ (endogenous agonist) and Mg2+ (endogenous inhibitor) on the kinetics of Ca2+ release from sarcoplasmic reticulum vesicles isolated from skeletal or cardiac mammalian muscle. Native skeletal vesicles exhibited maximal stimulation of release kinetics by 10-20 µM [Ca2+], whereas in native cardiac vesicles, maximal stimulation of release required only 1 µM [Ca2+]. In 10 µM [Ca2+], free [Mg2+] < 0.1 mM produced marked inhibition of release from skeletal vesicles but free [Mg2+]... |
| Tipo: Journal article |
Palavras-chave: Redox state; Ryanodine receptors; Sarcoplasmic reticulum; Calcium release kinetics; Mg2+ inhibition; S-nitrosoglutathione. |
| Ano: 2002 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602002000200009 |
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| ARTHUR,WILLIAM T.; NOREN,NICOLE K.; BURRIDGE,KEITH. |
| Integrins and cadherins are transmembrane adhesion receptors that are necessary for cells to interact with the extracellular matrix or adjacent cells, respectively. Integrins and cadherins initiate signaling pathways that modulate the activity of Rho family GTPases. The Rho proteins Cdc42, Rac1, and RhoA regulate the actin cytoskeleton. Cdc42 and Rac1 are primarily involved in the formation of protrusive structures, while RhoA generates myosin-based contractility. Here we examine the differential regulation of RhoA, Cdc42, and Rac1 by integrin and cadherin signaling. Integrin and cadherin signaling leads to a decrease in RhoA activity and activation of Cdc42 and Rac1. When the normal RhoA suppression is antagonized or RhoA signaling is increased, cells... |
| Tipo: Journal article |
Palavras-chave: Integrins; Cadherins; Adhesion; Rho; Rac; Cdc42. |
| Ano: 2002 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602002000200016 |
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| PÉREZ,LUZ MARÍA; BESOAÍN,XIMENA; REYES,MAURICIO; PARDO,GONZALO; MONTEALEGRE,JAIME. |
| Four isolates of Trichoderma harzianum (ThN3, Th11, Th12 and Th16) were selected for their ability to control the in vitro development of the tomato root pathogen Pyrenochaeta lycopersici. Analysis of the mechanisms involved in biocontrol showed that the formation of non-volatile metabolites appears to be one of those involved in biocontrol of P. lycopersici by all T. harzianum isolates tested. Nevertheless, the higher secretion of chitinases, both in number of isoenzymes and activity by the Th11 strain, correlated well with its higher ability to control this agent in laboratory and greenhouse experiments as compared to the other T. harzianum isolates tested. The secretion of ß -1,3-endoglucanases and/or proteases appeared to have less significance than... |
| Tipo: Journal article |
Palavras-chave: Biological control; Corky root; Tomato root diseases. |
| Ano: 2002 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602002000300014 |
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| CAMPOS-DE QUIROZ,HUGO. |
| Recent technological advancements have substantially expanded our ability to analyze and understand plant genomes and to reduce the gap existing between genotype and phenotype. The fast evolving field of genomics allows scientists to analyze thousand of genes in parallel, to understand the genetic architecture of plant genomes and also to isolate the genes responsible for mutations. Furthermore, whole genomes can now be sequenced. This review addresses these issues and also discusses ways to extract biological meaning from DNA data. Although genomic issuesare addressed from a plant perspective, this review provides insights into the genomic analyses of other organisms |
| Tipo: Journal article |
Palavras-chave: Genomics; Plant breeding; Gene discovery. |
| Ano: 2002 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602002000300013 |
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| THOMAS,GEORGE. |
| The discussion will focus on the role of the ribosomal protein S6 kinase (S6K) signaling pathway in the regulation of cell growth and proliferation. Although 40S ribosomal protein S6 phosphorylation was first described 25 years ago (<A HREF="#20">Gressner and Wool, 1974</A>), it only recently has been implicated in the translational up-regulation of mRNAs coding for the components of protein synthetic apparatus (<A HREF="#15">Fumagalli and Thomas, 2000</A>). These mRNAs contain an oligopyrimidine tract at their 5' transcriptional start site, termed a 5'TOP, which has been shown to be essential for their regulation at the translational level (<A HREF="#32">Meyuhas et al., 1996</A>). In parallel, a great deal of... |
| Tipo: Journal article |
Palavras-chave: Drosophila; SScells; Diabetes. |
| Ano: 2002 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602002000200022 |
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| WRIGHT,MARCIA M.; MCMASTER,CHRISTOPHER R.. |
| Apoptosis is a means by which organisms dispose of unwanted cells without inducing an inflammatory response. Alterations in apoptosis is a common process by which cells become cancerous. Paradoxically, many cancer chemotherapeutics preferentially kill cancer cells by inducing apoptosis. Diacylglycerol is a lipid second messenger that regulates cell growth and apoptosis and is produced during signal transduction by hydrolysis of membrane phospholipids. Protein kinase Cs are a family of diacylglycerol responsive enzymes that are recruited to cellular membranes as a consequence of diacylglycerol production where they phosphorylate specific target proteins responsible for regulating cell growth. In this review, we will first summarize our current understanding... |
| Tipo: Journal article |
Palavras-chave: Apoptosis; Diacylglycerol; Farnesol; Phorbol ester; Protein kinase C. |
| Ano: 2002 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602002000200014 |
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| ILLANES,JULIO; DABANCENS,ALFREDO; ACUÑA,OLGA; FUENZALIDA,MARCELA; GUERRERO,ANIBAL; LOPEZ,CLAUDIA; LEMUS,DAVID. |
| In this study, we showed the effect of the betamethasone, sulindac and quinacrine alone or combined, on the inflammatory angiogenesis promoted by polyurethane sponge on mice. The main finding reported here is that the formation of new blood vessels was strongly inhibited by low concentration of betamethasone, sulindac or quinacrine, whether alone or in combination. It is known that steroidal anti-inflammatory drugs inhibit the enzymes required for the production of prostaglandins through a nuclear glucocorticoid receptor (GR) mediated mechanism. This mechanism may occur in endothelial cells as well. Considering that activity of cyclo-oxigenases 1 and 2 is inhibited by sulindac, and that these enzymes are located in the stromal tissue, we propose that the... |
| Tipo: Journal article |
Palavras-chave: Angiogenesis; Antiangiogenesis; Betamethasone; Sulindac; Quinacrine. |
| Ano: 2002 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602002000300008 |
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| GALINDO,MARIO; GONZALEZ,M JULIETA; GALANTI,NORBEL. |
| Echinococcus granulosus is a parasitic platyhelminth that is responsible for cystic hydatid disease. From the inner, germinal layer of hydatid cysts protoscoleces are generated, which are are the infective forms to the dog. Systematic studies on the cell biology of E. granulosus protoscolex formation in natural infections are scarce and incomplete. In the present report we describe seven steps in the development of protoscoleces. Cellular buds formed by a clustering of cells emerge from the germinal layer of hydatid cysts. The buds elongate and the cells at their bases seem to diminish in number. Very early on a furrow appears in the elongated buds, delimiting anterior (scolex) and caudal (body) regions. Hooks are the first fully-differentiated structures... |
| Tipo: Journal article |
Palavras-chave: Protoscolex formation; Hydatid cyst. |
| Ano: 2002 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602002000300011 |
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| HERRIG,VANESSA; FERRARESE,MARIA DE LOURDES L.; SUZUKI,LETÍCIA S.; RODRIGUES,JOÃO DOMINGOS; FERRARESE-FILHO,OSVALDO. |
| The influence of the allelochemicals ferulic (FA) and vanillic (VA) acids on peroxidase (POD, EC 1.11.1.7) and phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) activities and their relationships with phenolic acid (PhAs) contents and root growth of soybean (Glycine max (L.) Merr.) were examined. Three-day-old seedlings were cultivated in nutrient solution containing FA or VA (0.1 to 1 mM) for 48 h. Both compounds (at 0.5 and 1 mM) decreased root length (RL), fresh weight (FW) and dry weight (DW) and increased PhAs contents. At 0.5 and 1 mM, FA increased soluble POD activity (18% and 47%, respectively) and cell wall (CW)-bound POD activity (61% and 34%), while VA increased soluble POD activity (33% and 17%) but did not affect... |
| Tipo: Journal article |
Palavras-chave: Roots; Phenolic acids; Phenylalanine ammonia-lyase; Peroxidase; Soybean. |
| Ano: 2002 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602002000100009 |
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| RAZIK,MONA A; CIDLOWSKI,JOHN A. |
| Apoptosis is the programmed and deliberate destruction of specific cells. This process occurs during normal development and maintains cellular homeostasis. Disruption or malfunction of apoptosis is implicated in diseases like cancer, AIDS as well as neurodegenerative disorders. The movement of monovalent ions appears to set the stage for the induction of the self-destruction machinery by creating an intracellular environment that favors activation and coordinated execution of the apoptotic program. Understanding the components and steps involved in this intricate process can further our insight to diseases and reveal new approaches for therapeutic treatment |
| Tipo: Journal article |
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| Ano: 2002 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602002000200011 |
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| Registros recuperados: 992 | |
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