242 results on '"Valenzuela, Pablo"'
Search Results
202. Acid catalyzed hydrolysis of neryl pyrophosphate and geranyl pyrophosphate.
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Valenzuela, Pablo, primary and Cori, Osvaldo, additional
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- 1967
- Full Text
- View/download PDF
203. Binding of competitive inhibitors to δ-chymotrypsin in the alkaline pH region. Competitive inhibition kinetics and proton-uptake measurements
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Valenzuela, Pablo, primary and Bender, Myron L., additional
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- 1970
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204. Kinetic properties of succinylated and ethylenediamine-amidated δ-chymotrypsins
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Valenzuela, Pablo, primary and Bender, Myron L., additional
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- 1971
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205. Conformation of δ-chymotrypsin during catalysis. Chemical reactivity of the isoleucine 16 amino group in the acyl-enzyme intermediate
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Valenzuela, Pablo, primary and Bender, Myron L., additional
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- 1971
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206. Difference between .alpha.- and .delta.-chymotrypsins. Preparation and alkaline pH dependence of .alpha.1-chymotrypsin-catalyzed hydrolysis of N-acetyl-L-tryptophan methyl ester (ATME). Involvement of alanine-149 in .alpha.-chymotrypsin catalysis
- Author
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Bender, Myron L., primary and Valenzuela, Pablo, additional
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- 1971
- Full Text
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207. Terpene biosynthesis: Formation of nerol, geraniol, and other prenols by an enzyme system from Pinus radiata seedlings
- Author
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Beytía, Enrique, primary, Valenzuela, Pablo, additional, and Cori, Osvaldo, additional
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- 1969
- Full Text
- View/download PDF
208. Occurrence of monoterpenes in Pinus radiata and utilization of labeled CO2 and mevalonic acid
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Valenzuela, Pablo, primary, Cori, Osvaldo, additional, and Yudelevich, Arturo, additional
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- 1966
- Full Text
- View/download PDF
209. Are all nucleotidyl transferases metalloenzymes?
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Valenzuela, Pablo, primary, Morris, Robert W., additional, Faras, Anthony, additional, Levinson, Warren, additional, and Rutter, William J., additional
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- 1973
- Full Text
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210. Acylation of α- and δ-Chymotrypsins by p-Nitrophenyl Acetate
- Author
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Hardman, Michael J., primary, Valenzuela, Pablo, additional, and Bender, Myron L., additional
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- 1971
- Full Text
- View/download PDF
211. ChemInform Abstract: UNTERSCHIED ZWISCHEN ALPHA- UND DELTA-CHYMOTRYPSINEN, DARST. VON ALPHA(1)-CHYMOTRYPSIN, CHYMOTRYPSIN-KATALYSIERTE HYDROLYSE VON N-ACETYL-L-TRYPTOPHAN-METHYLESTER, ALANIN-149 IN DER CHYMOTRYPSIN-KATALYSE
- Author
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VALENZUELA, PABLO, primary and BENDER, MYRON L., additional
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- 1971
- Full Text
- View/download PDF
212. Slope instabilities in the Asturian coast (N of Iberian Peninsula): a preliminary overview.
- Author
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Domínguez-Cuesta, María José, Valenzuela, Pablo, Jiménez-Sánchez, Montserrat, Rodríguez-Rodríguez, Laura, and Ballesteros, Daniel
- Subjects
- *
PENINSULAS , *COASTS - Published
- 2018
213. Occurrence of monoterpenes in Pinus radiata and utilization of labeled CO 2 and mevalonic acid
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Valenzuela, Pablo, Cori, Osvaldo, and Yudelevich, Arturo
- Published
- 1966
- Full Text
- View/download PDF
214. To [Missing], From Manuel V. Quiros Lozada, Pablo E. Macias Valenzuela, febrero 14 de 1941.
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Lozada, Manuel V. Quiros and Valenzuela, Pablo E. Macias
- Subjects
LETTERS ,VETERANS ,MEXICAN Revolution, Mexico, 1910-1920 - Published
- 1935
215. Proteínas nucleolares terminadoras de la replicación del rDNA y de la transcripción de los genes rRNA: papel en el control del ciclo celular y en la respuesta al estrés nutricional
- Author
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Rodríguez López, María, Hernández Valenzuela, Pablo, Hernandez, Pablo, and Ministerio de Ciencia e Innovación (España)
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Control del ciclo celular ,Parada G1 ,Diferenciación sexual ,Estrés nutricional ,Genética - Abstract
191 p.-35 fig.-11 tab.-anexos., Making use of the multiple molecular techniques available in the fission yeast Schizosaccharomyces pombe, we have been able to characterize a new function for the Reb1 protein, acting as a transcriptional regulator for genes involved in the stress response to nitrogen starvation. We have also found that this protein becomes essential when cells need to lengthen their G1 phase either due to a defect on the proteins required for passing through “start” or due to the need of reaching a certain size to passage through start. Reb1 is also needed for the survival upon entry into stationary phase in minimal medium. The ribosomal genes are usually organized as one or several arrays of tandemly repeated copies through the genome. In S. pombe, the rDNA consists of about 125 copies arranged in two arrays at both ends of chromosome III. A common feature observed in most organisms is that rDNA is replicated almost entirely in a unidirectional manner, with replication forks moving through the transcribed region in the direction of transcription. This is achieved by the presence of replication fork barriers (RFBs) located downstream the transcriptional units. It is believed that these RFBs serve as a mean to prevent the head on collision between replication and transcriptional machineries due to the high transcriptional rate of these genes even during DNA replication. In the fission yeast, three RFBs (RFB1-3) have been identified. A fourth replication fork pause (RFP4) can be visualized when any of the other barriers is not functional. All of S. pombe´s RFBs are dependent on the presence of the protein complex Swi1-Swi3. The RFB1, the one that gives the strongest signal and the closest one to the replication origin, is dependent on the presence of the swhitch activating protein Sap1 (Mejía-Ramírez et al., 2005). Reb1 is the protein that induces replication fork arrest at barriers RFB2 and RFB3, upon binding to two specific 17-bp sites (Sánchez-Gorostiaga et al., 2004). Binding of Reb1 to these two sites is also required for the termination of rRNA transcription by RNA polymerase I (Zhao et al., 1997). In this study we have found that Reb1 also binds in vivo and in vitro to a sequence upstream the promoter of the gene ste9+, participating in its up-regulation under nitrogen starvation (Rodríguez-Sánchez et al., 2011). Ste9 cooperates in the arrest of cells in G1 in reponse to nutritional stress. This is achieved by the anaphase-promoting complex/cyclosome (APC/C), which targets B-type cyclin for proteasome (Blanco et al., 2000)., G1 arrest enables cells to proceed through sexual differentiation, mating and spore formation to resist the harsh environment. Cells lacking Reb1 show a reduced arrest in G1 leading to a diminished fertility (Rodríguez-Sánchez et al., 2011) due to the inefficient expression of ste9+ during nitrogen deprivation. In addition to its function in the regulation of the G1 phase during nitrogen deprivation, we have also found that Reb1 becomes essential for viability when cells need to lengthen the G1 phase to reach the minimal size to begin replication, as in the thermosensitive wee1-50 mutant. The fission yeast shows a smart design to control the accurate size in which cells are born. This involves a mechanism based on gradients of inhibitory kinases, that in the last step regulates the activity of Cdc2, the only cyclin dependent kinase required in this yeast to drive the cell cycle. Wee1 is a kinase that phosphorilates Cdc2 (keeping the Cdc2-Cdc13 complex inactive) during G2 phase to prevent the premature entrance into mitosis if the cells have not reached the critical size for entering this phase. The combined reb1∆ wee1-50 mutants die of mitotic disaster after a couple of rounds of premature entrance into replication and mitosis. Reb1 is also essential for the viability of cells with defects in proteins required for the initiation of S-phase, as in cdc10-129 mutants. Cdc10 is a component of the transcriptional regulator complex MBF (Aligianni et al., 2009; Caetano et al., 2011), involved in controlling that the expression of the genes necessary for the entry into the S takes place only during G1 phase (McInerny et al., 1995). These data indicate that Reb1 is required to prevent the premature passage of cells through start. We have also found that during the course of the quiescent state induced upon reaching stationary phase on minimal medium, reb1∆ cells lose their viability at the early stages of stationary phase, showing a reduced chronological life span. Reb1 protein presents two Myb-type domains required for DNA binding. A protein interaction domain at its N-terminal end allows Reb1 to dimerize and interact with other proteins (Biswas y Bastia, 2008). We have found that during nitrogen starvation, Reb1 is processed through this N-terminal domain in a specific pattern, giving rise to different isoforms. The pattern of Reb1 isoforms is specific of the culture medium in which cells are growing. These different isoforms might be involved in the various cellular responses that we have attributed to Reb1. The exogenous expression of two of this isoforms is able to carry out all the Reb1 functions described above. Our latest work is centered on a high-throughput screening for other Reb1 binding sites on the fission yeast´s genome. This study has revealed that Reb1 binds upstream various genes, frequently around their transcription start sites. The gene ontology enrichment (Carmona-Saez et al., 2007; Nogales-Cadenas et al., 2009; Tabas-Madrid et al., 2012) of the genes whose promoters Reb1 binds to, shows that Reb1 might be involved in the transcriptional regulation of genes that participate in the regulation of cell cycle (e.g., ste9+, nim1+, cig2+, rbx1+, cdc18+), in the biosynthesis of secondary metabolites (e.g., fbp1+, pgk1+, gpm1+) and in the ubiquitin mediated degradation of proteins (cyp8+, ste9+ and rbx1+). Using real-time RT-PCR technique, we have been able to show that Reb1 is required for the transcriptional regulation of some of these genes in response to nitrogen starvation. The expression of genes nim1+, ste9+, cdc18+ and cig2+, is known to be up-regulated during nitrogen starvation, diminished in reb1∆ cells., stationary phase or under nitrogen starvation. Cells that lack Reb1 show no transcriptional up-regulation of ecl1+ upon entrance into stationary phase, nor upon nitrogen starvation. These results indicate that Reb1 acts as a transcriptional regulator protein for multiple genes in S. pombe. All together, the results described above lead us to propose a model in which Reb1 acts as a scaffold protein that tethers together different genomic regions (by dimerization or binding to other DNA binding proteins) (Singh et al., 2010) during non stressful conditions close to the nucleolus, where the stress response genes are silenced or expressed at baseline level. Upon sensing the absence of nitrogen, the protein interaction N-terminal domain of Reb1 is readily processed allowing the movement of the silenced chromosomal regions to a more transcription prone zone of the nucloeplasm. Processing of the N-terminal domain would not only allow the release of the Reb1-binding loci from the silenced nuclear zone, but it could also serve to activate the pro-transcriptional properties of Reb1. As the cells are kept under nitrogen starvation, Reb1 is further processed, switching off the transcription of the early Reb1-dependent nitrogen response genes. In the present work we have shown that Reb1 is a multifunctional protein acting in the regulation of several cellular processes in fission yeast, such as replication, transcription and stress response.
- Published
- 2016
216. Efecto borde en el bosque de encino de la Sierra de Monte Alto
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Marcela Yilotl Cazares Sanchez, García Romero, Arturo, Manzo Delgado, Lilia de Lourdes, Campo Alves, Julio Homero, Espinoza Rodríguez, José Manuel, Leautaud Valenzuela, Pablo, Arturo Garcia Romero, Lilia de Lourdes Manzo Delgado, Homero Julio Eudes Campo Alves, José Manuel Espinoza Rodríguez, and Pablo Leautaud Valenzuela
- Subjects
Ciencias Sociales ,4 [cti] - Abstract
Fuente TESIUNAM
- Published
- 2016
217. Transactivación de IRE1 y PERK por una molécula pequeña inhibidora de quinasa
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Morales Soto, Marisol, Bernales, Sebastián, and Valenzuela, Pablo
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Análisis celular ,Proteína Quinasa ,Antagonistas e Inhibidores - Abstract
Tesis (Doctor en Biotecnología) Las células eucariontes tienen la capacidad de responder a la acumulación de proteínas mal plegadas en el retículo endoplásmico a través de un mecanismo conocido como respuesta a proteínas mal plegadas (UPR). Dos de los tres sensores del UPR; IREl y PERK participan activamente en las decisiones de sobrevida y muerte celular, por lo que constituyen potenciales candidatos para blancos terapéuticos. Ambos sensores son proteínas quinasa y sus regiones luminales son altamente similares e intercambiables, lo que sugiere un mecanismo de activación común. IRE 1 además contiene un dominio endoribonucleasa yuxtapuesto al dominio quinasa. El uso del inhibidor de quinasa APY29, reveló que la ocupación de sitio ATP del dominio quinasa de IREl provoca un cambio conformacional que induce su transactivación y oligomerización, permitiendo así la activación de los dominios endon·ibonucleasa adyacentes. Recientemente se encontró que inhibidores de quinasa pueden actuar como agonistas de la actividad quinasa, al promover la transactivación y oligomerización. Dada la similitud en los mecanismos de activación entre IREl y PERK en esta tesis proponemos estudiar el efecto de análogos de APY29 sobre la actividad quinasa de PERK. Nuestros resultados indican que el análogo AM9 es más potente y selectivo que APY29 en la inducción de la actividad endoribonucleasa de IREl, tanto in vitro como en líneas celulares, y funciona promoviendo su transactivación y oligomerización. Este análogo además es capaz de unirse e inhibir la actividad quinasa de PERK in vitro. Sin embargo y de manera interesante, análisis en líneas celulares muestran que AM9 puede actuar, dependiendo de la concentración, como agonista y como un inhibidor de la actividad quinasa de PERK, mostrando una curva de activación tipo campana. Esto sugiere que PERK se activa por un mecanismo dependiente de transactivación y oligomerización. Nuestros resultados muestran que un mismo inhibidor de quinasa puede modular a dos de los tres sensores del UPR. Por otra parte, estos resultados demuestran que PERK es activable por inhibidores de quinasa, lo cual es importante de considerar durante el uso y diseño de drogas que apunten a este sensor del UPR. Eukaryotic cells have the capacity to respond to the accumulation of unfolded proteins in the endoplasmic reticulum via a mechanism known as the unfolded protein response (UPR). Two of the three sensors of the UPR, IRE 1 and PERK, are actively involved in decisions of survival and cell death, which makes them important candidates as therapeutic targets. Both sensors are kinases, IRE 1 also have an endoribonuclease domain, with highly similar and interchangeable luminal segment, suggesting a common activation mechanism. Using the small molecule kinase inhibitor APY29, it was revealed that the occupancy of the IREl kinase catalytic domain causes a conformational change that induces transactivation and oligomerization of the protein thereby activating its appended endoribonuclease domains. Moreover, it has been reported that in sorne cases kinase inhibitors may act as agonists of the kinase activity by promoting transactivation and oligomerization. Since IRE 1 and PERK are very similar in activation in this thesis we propose to study the effect of APY29 analogs on kinase activity of PERK. Our results indicate that in both, in vitro and in cell lines, the analog AM9 is a more potent and selective activator of IREl endoribonuclease activity than APY29, promoting its transactivation and oligomerization. Furthermore, AM9 is capable of binds and inhibits kinase activity of PERK in vitro. Nevertheless, analysis in cell lines shows that AM9 acts as both, agonist and antagonist of the PERK kinase activity, depending in the concentration, displaying a bell-shaped activation curve. This suggests that like IRE 1, PERK is activated by a mechanism involving transactivation and oligomerization. In summary, we show that the same kinase inhibitor can modulate two of the three UPR sensors. These results also suggest that PERK can be activated by a kinase inhibitor, this will be important to consider in the design of drugs that target PERK.
- Published
- 2013
218. Interferencia del ARN mitocondrial no codificante por lentivirus psuedotipificados
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Varas Godoy, Manuel, Burzio, Luis O., and Valenzuela, Pablo
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ARN ,Análisis celular ,Genética - Abstract
Tesis (Doctor en Biotecnología) Burzio y colaboradores han descrito una familia de ARNs mitocondriales no codificantes (ARNmtnc) denominados ARNmtnc Sentido (ARNmtnc-S) y ARNmtnc Antisentido (ARNmtnc-AS) que se encuentran diferencialmente expresados en células normales y tumorales. Células normales en proliferación expresan altos niveles tanto del ARNmtnc-S como del ARNmtnc-AS. En contraste, células que no están en división expresan bajos niveles de ambos transcritos. Interesantemente, células tumorales expresan el ARNmtnc-S y disminuyen la expresión del ARNmtnc-S. Estas características son observadas tanto en células en cultivo como en biopsias de tejidos. Previamente, Burzio y colaboradores demostraron que la transfección transiente con oligonucleótidos complementarios a estos ARNmtnc induce muerte en diferentes tipos de células cancerígenas in vitro, pero no en células normales, dando la posibilidad de usar la interferencia de estos ARNs mitocondriales como un potencial tratamiento contra el cáncer. El objetivo de este estudio fue determinar si la administración in vivo de lentivirus que codifican shRNA (del inglés short hairpain RNA) dirigidos contra los ARNmtnc podría inhibir el crecimiento tumoral y la metástasis en modelos animales de melanoma de ratón. Para esto se construyeron vectores lentivirales no-replicativos que codifican un shRNA contra los ARNmtnc (Lv-ARNmtnc) y luciferasa (Lv-Control) y su efecto fue evaluado in vitro por transducción de células de melanoma de ratón B16F10. Mediciones por PCR en tiempo real indican una disminución de aproximadamente 6 veces en la expresión del ARNmtnc-S y del ARNmtnc-AS en células transducidas con Lv-ARNmtnc en comparación a células transducidas con Lv-Control. Además, la transducción de Lv-ARNmtnc induce muerte celular apoptótica determinada por exposición en la superficie celular de fosfatidilserina y fragmentación del ADN. La capacidad de estos lentivirus para inhibir el crecimiento de tumores sólidos y metástasis de células de melanoma B16F10 fue evaluada in vivo. Ratones C57BLl6 a los cuales se les indujeron tumores subcutáneos con células B16F10 fueron tratados cada dos días con cinco inyecciones intratumorales de 4 x lo7 Lv-ARNmtnc o LV-Control en un volumen de 100 VI. Los ratones tratados con Lv-ARNmtnc mostraron una significativa disminución en el volumen tumoral comparado a ratones tratados con LV-Control observado hasta el día 20 post inoculación de las células. Para el ensayo de metástasis, ratones C57BLl6 fueron inyectados por vía intravenosa con células B16F10 y cuatro días después se les administraron cada tres días 4 inyecciones intravenosas de 5 x 10' Lv-ARNmtnc o Lv-Control en un volumen de 200 pl. Los ratones fueron sacrificados dos semanas después de la inyección de las células para el análisis de metástasis pulmonar. Los ratones tratados con Lv-ARNmtnc mostraron una significativa reducción en el número de focos metastásicos comparados a los ratones tratados con Lv-Control y también una reducción en el peso pulmonar. Tinción de secciones de tejido con hematoxilina-eosina indica que los pulmones de los ratones tratados con Lv-ARNmtnc presentan solo unos pocos nódulos. En contraste, los nódulos metastásicos ocupaban la mayoría del tejido pulmonar cuando los ratones fueron tratados con Lv-Control. Estos resultados sugieren que la administración intratumoral y sistémica de shRNA dirigidos a los ARNmtnc representan una promisoria estrategia hacia el desarrollo de una potencial terapia contra el cáncer.
- Published
- 2012
219. Interferencia del arn mitocondrial no codificante mediado por lentivirus pseudotipificados
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Varas-Godoy, Manuel Alejandro, Valenzuela, Pablo D T, Burzio, Luis O, and Universidad Andrés Bello
- Abstract
Burzio y colaboradores han descrito una familia de ARNs mitocondriales nocodificantes (ARNmtnc) denominados ARNmtnc Sentido (ARNmtnc-S) yARNmtnc Antisentido (ARNmtnc-AS) que se encuentran diferencialmenteexpresados en células normales y tumorales. Células Doctor en Biotecnología TERMINADA PFCHA-Becas 101p. PFCHA-Becas
- Published
- 2012
220. Aislamiento y caracterización del factor de transcripción ICE1 de Eucalyptus globulus
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Rasmussen Poblete, Susana Alejandra, Krauskopf, Erwin, and Valenzuela, Pablo
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Eucalyptus globulus ,Factores de Transcripción - Abstract
Tesis (Doctor en Biotecnología) ICE1 es un factor de transcripción que es activado en respuesta a condiciones de frío en plantas. Es considerado como el componente clave dentro de la cascada de señalización de frío, activando la respuesta mediada por los factores de transcripción de unión a e-repetidos (CBFs) y gatillando la expresión de los genes localizados río debajo de esta cascada. En esta tesis aislamos un cDNA que codifica para la proteína ICE1 de Eucalyptus g/obu/us (Eg/CE1) a partir de una librería de cDNA construida bajo condiciones de frío. La secuencia de cDNA posee un marco de lectura abierto de 1683 pb y codifica para una proteína de 560 aminoácidos, con un peso molecular estimado de 60,48 kDa y un pi calculado de 5,65. La comparación de la secuencia de cDNA con la obtenida a partir de DNA genómico demostró que Eg/CE1 no posee intrones, confirmándose la presencia de todos los dominios característicos de las proteínas ICE1 descritas actualmente. Adicionalmente, encontramos un dominio de activación extra, que probablemente aumenta la actividad del factor de transcripción EglCE1. Este dominio también está presente en proteínas ICE1 de otras especies de Eucalyptus. Ensayos de expresión transientes demostraron que EglCE1 es un factor de transcripción que se une a los promotores de genes CBF, de la misma forma que AtlCE1. EglCE1 es un regulador transcripcional, activando y reprimiendo los promotores de los genes CBFs en respuesta a bajas temperaturas. Los niveles de transcritos de Eg/CE1 aumentaron en respuesta a condiciones de frío y sequía. El análisis de expresión de los genes río abajo demostró que la abundancia relativa de los mRNA de EgCBF1 aumentó sólo en respuesta a bajas temperaturas y no fue detectado en condiciones de sequía. Por otro lado, la abundancia relativa del gen EgRD29B disminuyó en respuesta a bajas temperaturas y aumentó en respuesta a sequía. Por otro lado, los niveles de proteína EgICE1 no variaron en las mismas condiciones. Sin embargo, se demostró que EglCE1 se encuentra fosforilado tanto en frío, sequía y condiciones control. Proponemos que existen eventos de desfosforilación implicados en la regulación post-traduccional en respuesta a condiciones de estrés, pero estro debe ser determinado experimentalmente
- Published
- 2011
221. RNA de interferencia en nicotiana benthamiana como modelo para el desarrollo de plantas resistentes a virus
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Bruno Urbina, Consuelo, Valenzuela, Pablo, Facultad de Ciencias Biológicas, and Doctorado en Biotecnología
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Plantas -- Enfermedades y Plagas ,Plantas -- Enfermedades a Virus - Abstract
Tesis (Doctor en Biotecnología) RESUMEN: El cultivo de las vides es uno de los de mayor importancia económica para Chile, sin embargo, se ve afectado por numerosos factores, tanto bióticos como abióticos. Los virus se consideran entre los patógenos de mayor importancia para este cultivo y hasta el momento se han descrito más de 60 especies de virus que afectan vides. La mayoría de ellos se transmiten a través de vectores, como nemátodos o áfidos. Se piensa que las metodologías de propagación a través de estacas serían las responsables del incremento y amplia diseminación de estos virus en los últimos años. No existen antecedentes de resistencia natural en vides frente a la infección por virus y la búsqueda de nuevas variedades resistentes ha sido blanco de muchos esfuerzos en este campo de investigación. En este trabajo se describe el desarrollo de resistencia a virus de vides a través de la inducción de silenciamiento génico en plantas de tabaco. Consideramos de gran importancia trabajar con los virus más comunes en Chile, como son: Grapevine leafroll associated virus 2 y 3, Grapevine virus A, Grapevine fanleaf virus y Grapevine fleck virus, y utilizar secuencias de aislados chilenos para inducir el silenciamiento génico contra los virus. Se realizó un análisis de las secuencias disponibles, se utilizaron mayormente secuencias obtenidas en estudios previos en el laboratorio y se secuenciaron los virus de los que no se disponían secuencias de aislados locales. En este trabajo se presenta el caso de Grapevine fleck virus, para el cual se obtuvo la secuencia del 70% del genoma de un aislado chileno y los fragmentos codificantes para los dominios proteicos conservados de la replicasa viral para otros 3 aislados, con los que se analizó la variabilidad de este virus en Chile. En este trabajo, analizamos la capacidad de diferentes secuencias virales para gatillar el silenciamiento génico en plantas, y probamos la habilidad de algunas de ellas para inducir resistencia frente a la infección con el virus. Se eligieron fragmentos de las secuencias codificantes para proteínas esenciales para el virus, como proteínas de replicación, movimiento, cubierta y proteínas de shock térmico, de los diferentes virus. En este proceso de elección de las secuencias a utilizar para la inducción del silenciamiento génico, nos llamó particularmente la atención tres proteínas de Grapevine leafroll associated virus-3, las que no tienen función putativa asociada y basados principalmente en la similitud de la organización genómica de GLRaV-3 con virus de otra familia, planteamos la hipótesis de que pudieran actuar como supresores del silenciamiento génico. Se desarrolló análisis bioinformáticos para intentar proponer una función putativa para estas tres proteínas de GLRaV-3, los que arrojaron resultados significativos sólo para la proteína p19.6 de GLRaV-3, en la cual se identificó un putativo dominio de unión de RNA doble hebra del tipo arreglos de α-hélices, lo que sin embargo no nos permitió asociarle una putativa función por ser un dominio presente en... ABSTRACT: The grapevines are one of the most economically important crops in Chile; however, they are affected by many factors, both biotic and abiotic. Viruses are among the most important pathogens of this crop and thus far more than 60 species of viruses that affect grapevines have been described. Most of them are transmitted in the field by vectors such as nematodes or aphids, but it is thought that the propagation by cuttings would be responsible for the increase and widespread dissemination of these viruses in the last years. There are no records of natural resistance in grapevine against virus infection and the search for new resistant varieties has been the target of many efforts in this field of research. This thesis describes the development of grapevine virus resistance through induction of gene silencing in tobacco plants. We considered of great importance to work with the major viruses present in Chile, including: Grapevine leafroll associated virus 2 and 3, Grapevine virus A, Grapevine fanleaf virus and Grapevine fleck virus; and use of sequences of Chilean isolates to induce gene silencing against them. We did an analysis of the available sequences, most of the ones we used were obtained in previous studies in the laboratory and we sequenced the viruses that lack in local sequences. In this work we present the case of Grapevine fleck virus, for which we obtained the sequence of 70% of the genome of a Chilean isolate and the fragments coding for conserved protein domains of the viral replicase for other three isolates. In this work, we analyzed the ability of different viral sequences to trigger gene silencing in plants, and tested the ability of some of them to induce resistance against infection with the corresponding virus. We selected fragments of the coding sequences for proteins essential for the virus, such as replication, movement, coat proteins and heat shock proteins of the different viruses. In the comparison of the available sequences for the different viruses, and the choosing of the sequences to be used to induce gene silencing, we realized that the genomic organization of Grapevine leafroll associated virus-3, was quite conserved in the family Closteroviridae; most of the viruses of this family encodes for silencing suppressor proteins, and GLRaV-3 has three proteins with no putative function. We performed bioinformatic analyses trying to propose a putative function for these three proteins of GLRaV-3, which yielded significant results only for the p19.6 protein of GLRaV-3. A putative double stranded RNA binding domain was identified, which however did not allow us to associate a putative function because it is a very promiscuous domain that can be found in proteins of various functions. We analyzed the possible activity as a suppressor of gene silencing for the three proteins under study. The results indicate that none of them act as suppressors of gene silencing in our assays, but revealed that they may be able to interact with each other...
- Published
- 2011
222. Identificación y expresión de antígenos de streptococcus phocae en e. coli, y su ensayo como candidatos para una vacuna recombinante en salmón
- Author
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Manosalva Contreras, Headdy, Valenzuela, Pablo, Wilhlem Bavestrelllo, Vivian, Facultad de Ciencias de la Vida, and Escuela de Ingeniería en Biotecnología
- Subjects
Salmon ,Chile ,Prevención y Control ,Enfermedades ,Impacto Ecológico ,Costos Económicos - Abstract
Tesis (Doctor en Biotecnología) Streptococcus phocae es un patógeno emergente en la industria de la salmonicultura chilena. Este patógeno es el principal responsable del síndrome por cocáceas Gram positivas que afecta al salmón del Atlántico, causando importantes pérdidas económicas a las empresas. El control de esta enfermedad se basa actualmente en el uso de antibióticos, lo cual tiene un fuerte impacto ecológico, además de la problemática de comercializar salmones con trazas de antibióticos. Por lo tanto, en este trabajo se desarrolló como un método preventivo una vacuna experimental para salmones basada en una mezcla de antígenos recombinantes contra S. phocae. A partir de un salmón infectado se obtuvo un aislado bacteriano (Spl), identificado como S. phocae a través de la secuencia del gen de RNA ribosomal de 16s. En esta tesis se demostró que el patógeno es capaz de infectar salmones pre-smolt y smolt en agua temperada dulce o salobre a una temperatura óptima de 16OC. Además se obtuvo un segundo aislado (2868) a partir de un pez infectado con el aislado Spl, el cual fue más virulento, provocando tres veces más mortalidad en los peces que Spl en las mismas condiciones. Proteínas de S. phocae, cuyos ortólogos se localizan en la pared de especies de Streptococcus relacionados filogenéticamente con S. phocae, y confieren una determinada protección contra el correspondiente patógeno, fueron seleccionadas como potenciales candidatos para la vacuna experimental. Basándose en los dominios conservados de éstas, fueron diseñados partidores degenerados para amplificar las regiones codificantes de las chaperonas Hsp6O y Hsp70, Soda, los receptores de transportadores ABC de metales FebP y PsaA y las proteínas de superficie Sip y PrtS de S. phocae mediante PCR. Las regiones codificantes fueron clonadas en el vector de expresión bacteriano pET2la, lográndose una abundante expresión de las proteínas recombinantes en E. coli. El potencial antigénico de las proteínas fue evaluado in silico. Como resultado, Hsp70, PsaA, Sip y PrtS presentaron los más altos índices de antigenicidad. Esto fue confirmado experimentalmente. Salmones inmunizados con una mezcla de estas mismas proteínas mostraron una respuesta inmune humoral potenciada. Por lo tanto, la vacuna fue formulada con una mezcla de estas cuatro proteínas, extracto de E. coli y adyuvante de Freund incompleto. Alevines de salmón del Atlántico fueron vacunados con la preparación y desafiados en las condiciones óptimas de infección del patógeno, el desafío mostró una efectiva protección en salmón del Atlántico contra S. phocae, con un porcentaje relativo de sobrevivencia (RPS) de un 81%. Además, se demostró que el extracto de E. coli y el adyuvante de Freund incompleto presentes en la formulación multicomponente tienen un importante rol en la protección.
- Published
- 2007
223. Estudio de los factores implicados en la barrera para las horquillas de replicación RFB1 presente en los genes del rRNA de Schizosaccharomyces pombe
- Author
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Mejía Ramírez de Arellano, Eva María, Hernández Valenzuela, Pablo, and Universidad Autónoma de Madrid. Departamento de Biología Molecular
- Subjects
Biología ,ADN ribosómico - Replicación - Tesis doctorales - Abstract
Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 01-12-2006
- Published
- 2006
224. Cellulolytic yeast strains and their application
- Author
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Merja Penttilä, Päivi Lehtovaara, Jonathan Knowles, Barr, Philip J., Brake, Anthony J., and Valenzuela, Pablo
- Published
- 1989
225. Clinical characteristics and outcomes of people living with HIV hospitalized with COVID-19: a nationwide experience.
- Author
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Ceballos ME, Ross P, Lasso M, Dominguez I, Puente M, Valenzuela P, Enberg M, Serri M, Muñoz R, Pinos Y, Silva M, Noguera M, Dominguez A, and Zamora F
- Subjects
- Adult, Black or African American, Aged, Anti-HIV Agents therapeutic use, CD4 Lymphocyte Count, COVID-19 therapy, COVID-19 Serological Testing, Chile epidemiology, Critical Care, Female, HIV Infections drug therapy, HIV Infections epidemiology, Humans, Intensive Care Units, Male, Middle Aged, Pandemics, Prospective Studies, COVID-19 diagnosis, Coinfection immunology, Coinfection virology, HIV Infections complications, Hospitalization statistics & numerical data, SARS-CoV-2
- Abstract
In this prospective, multicentric, observational study, we describe the clinical characteristics and outcomes of people living with HIV (PLHIV) requiring hospitalization due to COVID-19 in Chile and compare them with Chilean general population admitted with SARS-CoV-2. Consecutive PLHIV admitted with COVID-19 in 23 hospitals, between 16 April and 23 June 2020, were included. Data of a temporally matched-hospitalized general population were used to compare demography, comorbidities, COVID-19 symptoms, and major outcomes. In total, 36 PLHIV subjects were enrolled; 92% were male and mean age was 44 years. Most patients (83%) were on antiretroviral therapy; mean CD4 count was 557 cells/mm
3 . Suppressed HIV viremia was found in 68% and 56% had, at least, one comorbidity. Severe COVID-19 occurred in 44.4%, intensive care was required in 22.2%, and five patients died (13.9%). No differences were seen between recovered and deceased patients in CD4 count, HIV viral load, or time since HIV diagnosis. Hypertension and cardiovascular disease were associated with a higher risk of death ( p = 0.02 and 0.006, respectively). Compared with general population, the HIV cohort had significantly more men (OR 0.15; IC 95% 0.07-0.31) and younger age (OR 8.68; IC 95% 2.66-28.31). In PLHIV, we found more intensive care unit admission (OR 2.31; IC 95% 1.05-5.07) but no differences in the need for mechanical ventilation or death. In this cohort of PLHIV hospitalized with COVID-19, hypertension and cardiovascular comorbidities, but not current HIV viro-immunologic status, were the most important risk factors for mortality. No differences were found between PLHIV and general population in the need for mechanical ventilation and death.- Published
- 2021
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226. Dataset: Ecosystem services and uses of dune systems of the coast of the Araucanía Region, Chile: A perception study.
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Arévalo-Valenzuela P, Peña-Cortés F, and Pincheira-Ulbrich J
- Abstract
The dataset shows the relationship and valuation of the coastal dunes of the Araucanía region in Chile. The valuation of the local population was surveyed using a questionnaire applied to 49 subjects belonging to Mapuche communities and local government. The data consists of eight tables that show a list of questions, the number of times per year that visit the dunes, cultural practices carried out in the dunes, valuation of ecosystem services provided by the coastal dunes, and knowledge about flora and fauna. Lastly, the original questionnaire and its responses in Spanish and English are included in supplemantary material. This dataset was generated within the framework of the manuscript "Ecosystem services and uses of dune systems of the coast of the Araucanía Region, Chile: a perception study" where 23 leaders of Mapuche communities and 26 representatives of the local government were interviewed. The dataset can be used to compare the valuation of ecosystems by local communities, especially when quantitative data are scarce or do not exist., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships which have, or could be perceived to have, influenced the work reported in this article., (© 2021 The Authors.)
- Published
- 2021
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227. Cryptococcus bacillisporus (VGIII) Meningoencephalitis Acquired in Santa Cruz, Bolivia.
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Thompson L, Porte L, Díaz V, Díaz MC, Solar S, Valenzuela P, Norley N, Pires Y, Carreño F, Valenzuela S, Shabani R, Rickerts V, and Weitzel T
- Abstract
We describe a case of chronic meningoencephalitis with hydrocephalus caused by Cryptococcus bacillisporus (VGIII) in an immunocompetent patient from Santa Cruz, Bolivia. This first report of a member of the Cryptococcus gattii species complex from Bolivia suggests that C. bacillisporus (VGIII) is present in this tropical region of the country and complements our epidemiological and clinical knowledge of this group of emerging fungal pathogens in South America.
- Published
- 2021
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228. [Epidemiology of invasive fungal disease by filamentous fungi in the period 2005 to 2015, in a university hospital in Santiago, Chile].
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Valenzuela P, Legarraga P, and Rabagliati R
- Subjects
- Adult, Aged, Antifungal Agents therapeutic use, Chile epidemiology, Female, Fungi, Humans, Male, Middle Aged, Retrospective Studies, Aspergillosis drug therapy, Invasive Fungal Infections drug therapy, Invasive Fungal Infections epidemiology
- Abstract
Background: Invasive fungal disease (IFD) due to filamentous fungi is increasingly common., Aim: To study the epidemiology of EFI in hospitalized adults in our center., Methods: Retrospective study of adult patients of a university hospital in Santiago, Chile, with EFI due to filamentous fungi between January 2005 and December 2015., Results: 125 episodes were identified, being 48% proven, 40% probable and 11% possible according to EORTC/MSG criteria, overall incidence was 0.47/1,000 admissions, 57% male patients and age 50 ± 16 years. 66.4% had hematological pathology, 11.2% solid organ transplant, 11.2% rheumatology diseases, 11.2% other conditions. The risk factors were neutropenia 44%, corticosteroid therapy 21%, immunosuppressants 13%. The most frequent mould identified were Aspergillus spp (53.6%), Mucorales (16%), Fusarium spp (8.8%), Alternaria spp (5.6%) and other filamentous (3.2%). All received antifungals, 82% monotherapy, 18% combined therapy, there was surgical defocation in 90% of mucormycosis. The overall mortality was 42%. When comparing 2005-2009 vs 2010-2015, there was a significant increase in incidence and a tendency to lower mortality in the second period., Conclusions: Over a period of 10 years, we observed an increase in the incidence of EFI by filamentous, aspergillosis was the most frequent etiology and the overall mortality was 42%.
- Published
- 2019
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229. In vivo knockdown of antisense non-coding mitochondrial RNAs by a lentiviral-encoded shRNA inhibits melanoma tumor growth and lung colonization.
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Varas-Godoy M, Lladser A, Farfan N, Villota C, Villegas J, Tapia JC, Burzio LO, Burzio VA, and Valenzuela PDT
- Subjects
- Animals, Apoptosis, Cell Proliferation, Gene Expression Regulation, Neoplastic, Gene Knockdown Techniques, Humans, Lung Neoplasms genetics, Lung Neoplasms secondary, Male, Melanoma genetics, Melanoma pathology, Mice, Mice, Inbred C57BL, RNA, Antisense genetics, RNA, Mitochondrial genetics, RNA, Untranslated genetics, Lentivirus genetics, Lung Neoplasms therapy, Melanoma therapy, RNA, Antisense antagonists & inhibitors, RNA, Mitochondrial antagonists & inhibitors, RNA, Small Interfering genetics, RNA, Untranslated antagonists & inhibitors
- Abstract
The family of non-coding mitochondrial RNAs (ncmtRNA) is differentially expressed according to proliferative status. Normal proliferating cells express sense (SncmtRNA) and antisense ncmtRNAs (ASncmtRNAs), whereas tumor cells express SncmtRNA and downregulate ASncmtRNAs. Knockdown of ASncmtRNAs with oligonucleotides induces apoptotic cell death of tumor cells, leaving normal cells unaffected, suggesting a potential application for developing a novel cancer therapy. In this study, we knocked down the ASncmtRNAs in melanoma cell lines with a lentiviral-encoded shRNA approach. Transduction with lentiviral constructs targeted to the ASncmtRNAs induced apoptosis in murine B16F10 and human A375 melanoma cells in vitro and significantly retarded B16F10 primary tumor growth in vivo. Moreover, the treatment drastically reduced the number of lung metastatic foci in a tail vein injection assay, compared to controls. These results provide additional proof of concept to the knockdown of ncmtRNAs for cancer therapy and validate lentiviral-shRNA vectors for gene therapy., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)
- Published
- 2018
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230. Prediction of bacterial microRNAs and possible targets in human cell transcriptome.
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Shmaryahu A, Carrasco M, and Valenzuela PD
- Subjects
- Cell Line, Host-Pathogen Interactions genetics, Host-Pathogen Interactions physiology, Humans, RNA, Bacterial physiology, MicroRNAs genetics, MicroRNAs physiology, RNA, Bacterial genetics, Transcriptome genetics
- Abstract
Recent studies have examined gene transfer from bacteria to humans that would result in vertical inheritance. Bacterial DNA appears to integrate into the human somatic genome through an RNA intermediate, and such integrations are detected more frequently in tumors than normal samples and in RNA than DNA samples. Also, vertebrate viruses encode products that interfere with the RNA silencing machinery, suggesting that RNA silencing may indeed be important for antiviral responses in vertebrates. RNA silencing in response to virus infection could be due to microRNAs encoded by either the virus or the host. We hypothesized that bacterial expression of RNA molecules with secondary structures is potentially able to generate miRNA molecules that can interact with the human host mRNA during bacterial infection. To test this hypothesis, we developed a pipeline-based bioinformatics approach to identify putative micro-RNAs derived from bacterial RNAs that may have the potential to regulate gene expression of the human host cell. Our results suggest that 68 bacterial RNAs predicted from 37 different bacterial genomes have predicted secondary structures potentially able to generate putative microRNAs that may interact with messenger RNAs of genes involved in 47 different human diseases. As an example, we examined the effect of transfecting three putative microRNAs into human embryonic kidney 293 (HEK293) cells. The results show that the bacterially derived microRNA sequence can significantly regulate the expression of the respective target human gene. We suggest that the study of these predicted microRNAs may yield important clues as to how the human host cell processes involved in human diseases like cancer, diabetes, rheumatoid arthritis, and others may respond to a particular bacterial environment.
- Published
- 2014
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231. Charting Brachyury-mediated developmental pathways during early mouse embryogenesis.
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Lolas M, Valenzuela PD, Tjian R, and Liu Z
- Subjects
- Animals, Chromatin Immunoprecipitation, Enhancer Elements, Genetic, Evolution, Molecular, Gene Expression Regulation, Developmental, Mice, Embryonic Development physiology, Fetal Proteins physiology, T-Box Domain Proteins physiology
- Abstract
To gain insights into coordinated lineage-specification and morphogenetic processes during early embryogenesis, here we report a systematic identification of transcriptional programs mediated by a key developmental regulator--Brachyury. High-resolution chromosomal localization mapping of Brachyury by ChIP sequencing and ChIP-exonuclease revealed distinct sequence signatures enriched in Brachyury-bound enhancers. A combination of genome-wide in vitro and in vivo perturbation analysis and cross-species evolutionary comparison unveiled a detailed Brachyury-dependent gene-regulatory network that directly links the function of Brachyury to diverse developmental pathways and cellular housekeeping programs. We also show that Brachyury functions primarily as a transcriptional activator genome-wide and that an unexpected gene-regulatory feedback loop consisting of Brachyury, Foxa2, and Sox17 directs proper stem-cell lineage commitment during streak formation. Target gene and mRNA-sequencing correlation analysis of the T(c) mouse model supports a crucial role of Brachyury in up-regulating multiple key hematopoietic and muscle-fate regulators. Our results thus chart a comprehensive map of the Brachyury-mediated gene-regulatory network and how it influences in vivo developmental homeostasis and coordination.
- Published
- 2014
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232. Transcriptome profiling of Botrytis cinerea conidial germination reveals upregulation of infection-related genes during the prepenetration stage.
- Author
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Leroch M, Kleber A, Silva E, Coenen T, Koppenhöfer D, Shmaryahu A, Valenzuela PD, and Hahn M
- Subjects
- Amidohydrolases metabolism, Botrytis metabolism, Carboxylic Ester Hydrolases metabolism, Fungal Proteins metabolism, Gene Expression Profiling, Genes, Reporter, Green Fluorescent Proteins, Models, Biological, Plant Diseases microbiology, Plants microbiology, Spores, Fungal metabolism, Transcription Factors metabolism, Waxes chemistry, Amidohydrolases genetics, Botrytis genetics, Carboxylic Ester Hydrolases genetics, Fungal Proteins genetics, Gene Expression Regulation, Fungal, Spores, Fungal genetics, Transcription Factors genetics
- Abstract
Botrytis cinerea causes gray mold on a great number of host plants. Infection is initiated by airborne conidia that invade the host tissue, often by penetration of intact epidermal cells. To mimic the surface properties of natural plant surfaces, conidia were incubated on apple wax-coated surfaces, resulting in rapid germination and appressorium formation. Global changes in gene expression were analyzed by microarray hybridization between conidia incubated for 0 h (dormant), 1 h (pregermination), 2.5 h (postgermination), 4 h (appressoria), and 15 h (early mycelium). Considerable changes were observed, in particular between 0 h and 1 h. Genes induced during germination were enriched in those genes encoding secreted proteins, including lytic enzymes. Comparison of wild-type and a nonpathogenic MAP kinase mutant (bmp1) revealed marked differences in germination-related gene expression, in particular related to secretory proteins. Using promoter-GFP reporter strains, we detected a strictly germination-specific expression pattern of a putative chitin deacetylase gene (cda1). In contrast, a cutinase gene (cutB) was found to be expressed only in the presence of plant lipids, in a developmentally less stringent pattern. We also identified a coregulated gene cluster possibly involved in secondary metabolite synthesis which was found to be controlled by a transcription factor also encoded in this cluster. Our data demonstrate that early conidial development in B. cinerea is accompanied by rapid shifts in gene expression that prepare the fungus for germ tube outgrowth and host cell invasion.
- Published
- 2013
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233. First detection and complete genome sequence of Deformed wing virus in Chilean honeybees.
- Author
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Barriga GP, Cifuentes-Muñoz N, Rivera PA, Gutierrez M, Shmaryahu A, Valenzuela PD, and Engel EA
- Subjects
- Animals, Base Sequence, Chile, Insect Viruses classification, Insect Viruses isolation & purification, Insect Viruses pathogenicity, Phylogeny, Picornaviridae classification, Picornaviridae isolation & purification, Picornaviridae pathogenicity, RNA, Viral genetics, Reverse Transcriptase Polymerase Chain Reaction, Wings, Animal pathology, Wings, Animal virology, Bees virology, Genome, Viral, Insect Viruses genetics, Picornaviridae genetics
- Abstract
Deformed wing virus (DWV) is one of the most common viruses affecting honey bee specimens. Although the presence of DWV has been reported in many countries, there is no data of the current situation in Chile. In this report, we detected the presence of DWV in apiaries from two different locations in central Chile. Furthermore, the genome of a Chilean DWV isolate was completely sequenced. This is the first report of the presence of a honey bee virus in Chile.
- Published
- 2012
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234. Aromatic and polar residues spanning the candidate fusion peptide of the Andes virus Gc protein are essential for membrane fusion and infection.
- Author
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Cifuentes-Muñoz N, Barriga GP, Valenzuela PD, and Tischler ND
- Subjects
- Amino Acid Substitution genetics, Amino Acids chemistry, Amino Acids metabolism, Animals, Cell Fusion, Cell Line, Chlorocebus aethiops, Flow Cytometry methods, Genes, Reporter, Green Fluorescent Proteins metabolism, Humans, Mutagenesis, Site-Directed, Mutant Proteins genetics, Mutant Proteins metabolism, Protein Binding, Staining and Labeling methods, Amino Acids genetics, Orthohantavirus pathogenicity, Membrane Fusion, Viral Fusion Proteins genetics, Viral Fusion Proteins metabolism, Virus Internalization
- Abstract
Hantaviruses infect human cells through cell attachment and subsequent fusion of viral and cellular membranes at low pH. This largely unknown entry process is mediated by the Gn and Gc glycoproteins, anchored at the viral envelope membrane. Performing bioinformatic analysis and peptide-liposome-binding assays we suggested in a former report that Gc of Andes virus (ANDV) and other hantaviruses corresponds to the viral fusion protein sharing characteristics with class II fusion proteins. To gain insights into the fusion protein of hantaviruses, residues within the previously predicted fusion peptide of ANDV Gc were substituted and mutant proteins tested in fusion and infection assays. To ensure proper folding of mutant proteins, they were first characterized for trafficking to the plasma membrane and incorporation on to ANDV Gn/Gc-pseudotyped lentiviral particles. Cell attachment of these particles was assessed using a newly developed binding assay and their subsequent entry properties determined by FACS analysis of transduced cells expressing the GFP reporter gene. Furthermore, a three-colour-based cell-cell fusion assay of ANDV Gn/Gc expressing cells was performed. The results indicate an essential role of conserved Gc residues W115 and N118 in membrane fusion. Conversely, substitutions of the non-conserved Gc residue G116 did not considerably affect fusion and infection. Altogether, the findings are fully consistent with our earlier prediction suggesting Gc residues 115-121 as an internal fusion peptide and further emphasize the importance of aromatic and polar residues in hantavirus-cell membrane fusion.
- Published
- 2011
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- View/download PDF
235. A diagnostic oligonucleotide microarray for simultaneous detection of grapevine viruses.
- Author
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Engel EA, Escobar PF, Rojas LA, Rivera PA, Fiore N, and Valenzuela PD
- Subjects
- Molecular Sequence Data, Oligonucleotide Probes genetics, Plant Viruses genetics, RNA, Viral genetics, Reverse Transcriptase Polymerase Chain Reaction, Sensitivity and Specificity, Sequence Analysis, DNA, Oligonucleotide Array Sequence Analysis methods, Plant Diseases virology, Plant Viruses classification, Plant Viruses isolation & purification, Vitis virology
- Abstract
At least 58 viruses have been reported to infect grapevines causing economic damage globally. Conventional detection strategies based on serological assays, biological indexing and RT-PCR targeting one or few viruses in each assay are widely used. Grapevines are prone to contain mixed infections of several viruses, making the use of these techniques time-consuming. A 70-mer oligonucleotide microarray able to detect simultaneously a broad spectrum of known viruses as well as new viruses by cross-hybridization to highly conserved probes is reported in the present study. The array contains 570 unique probes designed against highly conserved and species-specific regions of 44 plant viral genomes. In addition probes designed against plant housekeeping genes are also included. By using a random primed RT-PCR amplification strategy of grapevine double stranded RNA-enriched samples, viral agents were detected in single and mixed infections. The microarray accuracy to detect 10 grapevine viruses was compared with RT-PCR yielding consistent results. For this purpose, grapevine samples containing single or mixed infections of Grapevine leafroll-associated virus-1, -2, -3, -4, -7, -9, Grapevine fanleaf virus, Grapevine rupestris stem pitting-associated virus, Grapevine virus A, and Grapevine virus B were used. Genomic libraries containing complete viral genomes were also used as part of the validation process. The specific probe hybridization pattern obtained from each virus makes this approach a powerful tool for high throughput plant certification purposes and also for virus discovery if the new viral genomic sequences have partial similarity with the microarray probes. Three Closteroviridae members (Grapevine leafroll-associated virus -4, -7 and -9) were detected for the first time in Chilean grapevines using the microarray., (2009 Elsevier B.V. All rights reserved.)
- Published
- 2010
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236. Draft genome sequence of the extremely acidophilic bacterium Acidithiobacillus caldus ATCC 51756 reveals metabolic versatility in the genus Acidithiobacillus.
- Author
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Valdes J, Quatrini R, Hallberg K, Dopson M, Valenzuela PD, and Holmes DS
- Subjects
- Acidithiobacillus genetics, Computational Biology, Genes, Bacterial, Genomic Library, Molecular Sequence Data, Acidithiobacillus metabolism, Bacterial Proteins genetics, Bacterial Proteins metabolism, Genome, Bacterial, Sequence Analysis, DNA
- Abstract
Acidithiobacillus caldus is an extremely acidophilic, moderately thermophilic, chemolithoautotrophic gammaproteobacterium that derives energy from the oxidation of sulfur and reduced inorganic sulfur compounds. Here we present the draft genome sequence of Acidithiobacillus caldus ATCC 51756 (the type strain of the species), which has permitted the prediction of genes for survival in extremely acidic environments, including genes for sulfur oxidation and nutrient assimilation.
- Published
- 2009
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237. Isolation and characterization of the equine influenza virus causing the 2006 outbreak in Chile.
- Author
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Müller I, Pinto E, Santibáñez MC, Celedón MO, and Valenzuela PD
- Subjects
- Animals, Chile epidemiology, Horse Diseases epidemiology, Horses, Influenza A Virus, H3N8 Subtype genetics, Orthomyxoviridae Infections epidemiology, Orthomyxoviridae Infections virology, Phylogeny, Horse Diseases virology, Influenza A Virus, H3N8 Subtype classification, Influenza A Virus, H3N8 Subtype isolation & purification, Orthomyxoviridae Infections veterinary
- Abstract
The equine influenza virus is the causal agent of influenza in horses. In July 2006, horses from various regions of Chile presented fever, serious nasal discharge, dry cough, anorexia and depression. Here we describe the isolation and characterization of the virus responsible for this outbreak. The virus was identified as equine influenza virus H3N8, since haemagglutination was inhibited by an anti-A/equi/1/H3N8 serum, but not by an anti-A/equi/1/H7N7 serum. The isolate was named A/equi/2/Lonquén/06 (H3N8). In addition, we describe the isolation and sequencing of the haemagglutinin, neuraminidase and nucleoprotein genes of this new isolate. Sequence alignments show important differences with the Santiago/85 isolate and a closer relation to North American isolates, especially with the Florida lineage, and to Argentina isolates from 1990s.
- Published
- 2009
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- View/download PDF
238. Preparation and analysis of an expressed sequence tag library from the toxic dinoflagellate Alexandrium catenella.
- Author
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Uribe P, Fuentes D, Valdés J, Shmaryahu A, Zúñiga A, Holmes D, and Valenzuela PD
- Subjects
- Animals, Contig Mapping, DNA, Protozoan genetics, Databases, Genetic, Gene Library, Genomics, Molecular Sequence Data, Sequence Analysis, DNA, Dinoflagellida genetics, Expressed Sequence Tags
- Abstract
Dinoflagellates of the genus Alexandrium are photosynthetic microalgae that have an extreme importance due to the impact of some toxic species on shellfish aquaculture industry. Alexandrium catenella is the species responsible for the production of paralytic shellfish poisoning in Chile and other geographical areas. We have constructed a cDNA library from midexponential cells of A. catenella grown in culture free of associated bacteria and sequenced 10,850 expressed sequence tags (ESTs) that were assembled into 1,021 contigs and 5,475 singletons for a total of 6,496 unigenes. Approximately 41.6% of the unigenes showed similarity to genes with predicted function. A significant number of unigenes showed similarity with genes from other dinoflagellates, plants, and other protists. Among the identified genes, the most expressed correspond to those coding for proteins of luminescence, carbohydrate metabolism, and photosynthesis. The sequences of 9,847 ESTs have been deposited in Gene Bank (accession numbers EX 454357-464203).
- Published
- 2008
- Full Text
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239. Genome analysis and detection of a Chilean isolate of Grapevine leafroll associated virus-3.
- Author
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Engel EA, Girardi C, Escobar PF, Arredondo V, Domínguez C, Pérez-Acle T, and Valenzuela PD
- Subjects
- Amino Acid Sequence, Chile, Closteroviridae classification, Closteroviridae genetics, Closteroviridae metabolism, Molecular Sequence Data, Open Reading Frames, Phylogeny, Sequence Alignment, Sequence Analysis, DNA, Viral Proteins analysis, Viral Proteins metabolism, Closteroviridae isolation & purification, Enzyme-Linked Immunosorbent Assay methods, Genome, Viral, Plant Diseases virology, Reverse Transcriptase Polymerase Chain Reaction methods, Virology methods, Vitis virology
- Abstract
The complete genome of the Chilean isolate Cl-766 of Grapevine leafroll-associated virus-3 (GLRaV-3) has been sequenced. This is the first genome sequence obtained from a GLRaV-3 isolate of the Southern hemisphere. The genomic RNA of 17,919 nucleotides contains 13 open reading frames (ORFs) with 5' and 3' untranslated regions (UTR) of 158 and 277 nucleotides, respectively. Comparison with NY1, the only isolate with complete genomic sequence available today, shows 97.6% nucleotide identity between the two isolates. Examination of the genome variability shows that most of the genetic diversity is concentrated in ORF1a. Three additional isolates from different geographic regions of Chile were partially sequenced as well, one which showed sequence divergence with respect to the other local and foreign isolates, indicative of different evolutionary constrains. Immunodetection systems were developed using monoclonal and polyclonal antibodies produced against the recombinant major coat protein of GLRaV-3, providing sensitive and specific detection using a triple antibody sandwich-enzyme linked immunosorbent assay (TAS-ELISA) and an immunocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR) assay.
- Published
- 2008
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240. A vaccine against the salmonid pathogen Piscirickettsia salmonis based on recombinant proteins.
- Author
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Wilhelm V, Miquel A, Burzio LO, Rosemblatt M, Engel E, Valenzuela S, Parada G, and Valenzuela PD
- Subjects
- Animals, Bacterial Proteins immunology, Bacterial Vaccines adverse effects, Female, Fish Diseases microbiology, Lethal Dose 50, Mice, Mice, Inbred BALB C, Piscirickettsiaceae Infections prevention & control, Recombinant Proteins immunology, Salmo salar, Bacterial Vaccines immunology, Fish Diseases prevention & control, Piscirickettsiaceae immunology, Piscirickettsiaceae Infections veterinary
- Abstract
We report here the protective effect against piscirickettsiosis elicited in fish by a mixture of recombinant proteins. A comparative genomics strategy was used on a genomic library of Piscirickettsia salmonis in order to select optimal candidates for a recombinant subunit vaccine to protect fish from rickettsial septicaemia (SRS). Based on this information, 15 P. salmonis ORFs encoding heat shock proteins, virulence factors, membrane bound and other surface exposed antigens, were isolated and expressed. Seven of the most promising antigens were formulated in three mixtures (V1-V3) containing two or three recombinant proteins each and injected into salmon to test their protective efficacy. Two of the three formulations (V1, V2) elicited a strong protective response in a challenge against the pathogen, which was coincident with the humoral response against the corresponding recombinant proteins present in each formulation. V1, formulated with recombinant chaperonines Hsp60, Hsp70 and flagellar protein FlgG of P. salmonis achieved the highest level of protection with a relative percent survival (RPS) of 95%.
- Published
- 2006
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241. [Experience with electronic files in a university neonatology unit].
- Author
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Aguila A and Valenzuela P
- Subjects
- Abstracting and Indexing, Hospital Units, Hospitals, University, Humans, Local Area Networks, Medical Records Systems, Computerized organization & administration, Neonatology
- Abstract
The electronic file is a reality in medical practice nowadays. We have a decade of experience with electronic files in a neonatology unit. We use a local network that consists in one server and 8 connected computers, distributed in the hospital. Filemaker Pro is used as database administrator and access to data is protected with passwords. Data entry is made by health care professionals in charge of the patients. Patient's reports and statistical information are based on data entered to the system. This methodology allows to have update clinical data, indexing of information, to maintain track of pharmacological indications, prescribe parenteral nutrition and obtain information for research purpose. It is possible therefore, with a minimal computing expertise, to devise electronic files that can improve the quality of health care.
- Published
- 2005
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242. Detection of Piscirickettsia salmonis in fish tissues by an enzyme-linked immunosorbent assay using specific monoclonal antibodies.
- Author
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Aguayo J, Miquel A, Aranki N, Jamett A, Valenzuela PD, and Burzio LO
- Subjects
- Alphaproteobacteria immunology, Animals, Antibody Specificity, Cell Line, Cross Reactions, Enzyme-Linked Immunosorbent Assay methods, Fish Diseases microbiology, Fluorescent Antibody Technique, Indirect methods, Fluorescent Antibody Technique, Indirect veterinary, Gram-Negative Bacterial Infections diagnosis, Gram-Negative Bacterial Infections microbiology, Sensitivity and Specificity, Alphaproteobacteria isolation & purification, Antibodies, Monoclonal, Enzyme-Linked Immunosorbent Assay veterinary, Fish Diseases diagnosis, Gram-Negative Bacterial Infections veterinary, Salmonidae
- Abstract
An enzyme-linked immunosorbent assay (ELISA) for the detection of Piscirickettsia salmonis in fish tissue samples was developed. The test uses a combination of different monoclonal antibodies specific against P. salmonis in the capture step of the assay. The antibodies 7G4, 6E2 and 2C1 chosen for the capture step are bound to the solid support with an adhesive protein purified from a bivalve mollusc, resulting in a high yield of adsorption and binding stability. The monoclonal antibody 7G4, used as a second antibody, is conjugated to horseradish peroxidase. The resulting ELISA test detected 7 different isolates of P. salmonis and does not cross-react with several other fish pathogens, revealing a high specificity and sensitivity. The test also detects P. salmonis in kidney tissue of infected coho salmon with 98% correlation with the immunofluorescence assay.
- Published
- 2002
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