Oscar Fernando Garcia Mendoza - Academia.edu (original) (raw)
Papers by Oscar Fernando Garcia Mendoza
Revista Veterinaria, 2021
El salazonado de pescado es una forma antigua y económica de preservación que se usa aún en paíse... more El salazonado de pescado es una forma antigua y económica de preservación que se usa aún en países en vías de desarrollo como el Perú. En la región Tumbes, es común la comercialización de caballa (Scomber japonicus peruanus) salada artesanalmente, por lo cual su inocuidad microbiológica no está garantizada. La presente investigación tuvo como objetivo identificar, mediante el secuenciamiento de un fragmento del gen 16S ARNr, las bacterias cultivables presente en la caballa salada comercializada en Tumbes. A partir de tejido del músculo de la caballa, se aislaron cepas bacterianas en medio TSA suplementado con 15% de NaCl, de las que luego se obtuvieron fragmentos del gen 16S ARNr, que fueron secuenciados para luego identificar la especie a la que pertenecieron mediante una búsqueda en Genbank. Adicionalmente se analizaron el contenido de humedad y de NaCl del músculo de la caballa salada. Como resultado se identificaron cepas típicas de productos salados como: Staphylococcus sp, Hal...
Revista de Investigaciones Veterinarias del Perú, 2021
El objetivo de la presente investigación fue aislar, seleccionar y caracterizar genéticamente bac... more El objetivo de la presente investigación fue aislar, seleccionar y caracterizar genéticamente bacterias nativas de Argopecten purpuratus que, a través de un biofilm, estimulen su asentamiento larval. Conociendo que el asentamiento larval es el principal problema que afronta la reproducción en laboratorio de este molusco, se utilizó un biofilm bacteriano para mejorar porcentualmente la fijación larval. Se aislaron cepas bacterianas nativas del cultivo de A. purpuratus y se caracterizaron taxonómicamente a partir del análisis de las secuencias parciales del gen 16S rARN, amplificadas mediante PCR a cada una de las muestras de ADN extraídas de las cepas bacterianas aisladas. Al analizar las secuencias se identificó a nivel de género tres cepas bacterianas; Oceanobacillus, Bacillus y Pseudomonas. Además, se avaluó la eficiencia de fijación de larvas de A. purpuratus en los biofilms formados por las cepas Oceanobacillus y Bacillus logrando una fijación de 12 y 14%, en tanto que al estar ...
This project was developed by the opportunity that nowadays sports, especially football has gone ... more This project was developed by the opportunity that nowadays sports, especially football has gone from being a simple way to exercise and demonstrate skills to a business investment. Here works basically 2 areas: The Football Soccer as a sport and recreation, and the latter establishments commonly known as "synthetic grass courts." In Ecuador there are several places that offer hourly rental synthetic grass courts allowing playing football in a nice place to assist with who handle the same affinity and set up matches with friends or co-workers and even complete Championships. In the Canton General Villamil Playas, a large proportion of the population practice football but in conditions which are not nice nor proper to practice, and there are only two football fields, which are used to organize parties and championships but this is insufficient to meet the demand for people who enjoy this sport This is the reason why it is necessary to create a project focused on the constru...
COMPRA RAPIDO was born from an idea of three young entrepreneurs who seek to provide a different ... more COMPRA RAPIDO was born from an idea of three young entrepreneurs who seek to provide a different kind of online service, which is an important and necessary in this era where technology goes hand in hand with the daily lives of people. Is aimed at businesses, homes, in which it is difficult to go to the supermarket to choose the products you are interested, so, our website offers the convenience of getting them quickly. Provide service to make grocery shopping online. Our company offers the products on the market in a different way because of the facilities offered in the types of delivery schedule availability, affordability, etc.
Discovery Fiesta Cruises is a maritime craft that devotes itself to give the service of fluvial t... more Discovery Fiesta Cruises is a maritime craft that devotes itself to give the service of fluvial tourism. The company was founded in 1991. Nowadays there is rolled in the “Malecon Simon Bolivar” of the city of Guayaquil, where the first
Presentamos resultados de una investigacion relacionada con el aprendizaje de las soluciones de s... more Presentamos resultados de una investigacion relacionada con el aprendizaje de las soluciones de sistemas de ecuaciones lineales (SEL 2x2) consistentes e inconsistentes, a traves de conversiones entre los registros: verbal, algebraico-simbolico y grafico y tratamiento en ellos con el apoyo de software (e.g., GeoGebra). Los datos fueron analizados por tres conceptos los cuales obtuvimos de confluir las teorias Cambio de atencion y Representaciones semioticas . En el estudio participaron 25 estudiantes de nivel superior de entre 19 y 23 anos. La metodologia fue de tipo cualitativo. Se describen las respuestas de dos equipos al resolver tres problemas. Los resultados indican que los equipos lograron resolver los problemas asociados a SEL 2x2 consistentes con solucion unica, mediante la conversion entre el registro verbal y el registro grafico, pero tuvieron dificultades al resolver los problemas asociados a SEL 2x2 inconsistentes y consistentes con infinidad de soluciones.
Manglar, 2015
Crecimiento y supervivencia de Anadara tuberculosa (Sowerby, 1833) a tres densidades Growth and s... more Crecimiento y supervivencia de Anadara tuberculosa (Sowerby, 1833) a tres densidades Growth and survival of Anadara tuberculosa (Sowerby, 1833) on three densities
Revista Repertorio de Medicina y Cirugía, 2018
Para la Sociedad de Cirugía de Bogotá, Hospital de San José, es un honor haber contado con la pre... more Para la Sociedad de Cirugía de Bogotá, Hospital de San José, es un honor haber contado con la presencia del doctor Josep Brugada en el marco del Segundo Simposio SDC, muerte súbita cardiovascular, del proyecto PR-Chagas, financiado por Colciencias y organizado en conjunto con docentes de la Fundación Universitaria de Ciencias de la Salud. La enfermedad de Chagas es una de las enfermedades transmitidas por vectores de mayor importancia en salud pública en el país, en especial por las manifestaciones de la fase crónica que afectan al corazón. El vector de la enfermedad es el triatómino, un tipo de insecto hematófago que se encuentra distribuido en diferentes regiones de nuestro país, poniendo en riesgo de padecer la infección a cerca de 8 millones de nuestros compatriotas generando una importante prevalencia de la miocardiopatía chagásica en diversos departamentos, siendo acorde con estadísticas de la Organización Mundial de la Salud que estima en cerca de 10 millones las personas inf...
INGENIERÍA Y COMPETITIVIDAD, 1970
Este trabajo considera un exoesqueleto de miembros inferiores actuado en cadera y rodilla, con to... more Este trabajo considera un exoesqueleto de miembros inferiores actuado en cadera y rodilla, con torso y pies de apoyo portando un maniquí; se presenta el diseño e implementación de una estrategia de control para el equilibrio estático del exoesqueleto-maniquí, consistente en un control distribuido de bajo nivel para el posicionamiento angular de las articulaciones y de un control centralizado de alto nivel para el equilibrio. Para el control de posicionamiento angular en las articulaciones actuadas se diseñaron controladores PID; este control permite el seguimiento de trayectorias de posición en las articulaciones, preestablecidas por la estrategia de control de alto nivel. A partir del cálculo de la desviación horizontal del centro de masa del sistema total, el control de equilibrio estático manipula las articulaciones para compensar los disturbios de pequeña señal en la postura del exoesqueleto-maniquí. Se establece un protocolo para obtener los parámetros de la ley de control y la...
Biochimica et biophysica acta, May 6, 2017
G-quadruplexes (G4) are RNA and DNA secondary structures formed by the stacking of guanine quarte... more G-quadruplexes (G4) are RNA and DNA secondary structures formed by the stacking of guanine quartets in guanine rich sequences. Quadruplex-prone motifs may be found in key genomic regions such as telomeres, ribosomal DNA, transcriptional activators and regulators or oncogene promoters. A number of proteins involved in various biological processes are able to interact with G4s. Among them, proteins dedicated to nucleic acids unwinding such as WRN, BLM, FANCJ or PIF1, can unfold G4 structures. Mutations of these helicases are linked to genome instability and to increases in cancer risks. Here, we present a high-throughput fluorescence-based reliable, inexpensive and fast assay to study G4/RHAU interaction. RHAU is an RNA helicase known as the major source of G4 resolution in HeLa cells. Our assay allows to monitor the unfolding properties of RHAU towards DNA and RNA quadruplexes in parallel and to screen for the optimal conditions for its activity. This article is part of a Special Iss...
The Journal of chemical physics, Jan 14, 2017
Logic circuits based on DNA strand displacement reaction are the basic building blocks of future ... more Logic circuits based on DNA strand displacement reaction are the basic building blocks of future nanorobotic systems. The circuits tethered to DNA origami platforms present several advantages over solution-phase versions where couplings are always diffusion-limited. Here we consider a possible implementation of one of the basic operations needed in the design of these circuits, namely, signal replication. We show that with an appropriate preparation of the initial state, signal replication performs in a reproducible way. We also show the existence of side effects concomitant to the high effective concentrations in tethered circuits, such as slow leaky reactions and cross-activation.
![Research paper thumbnail of Design, Synthesis, and Evaluation of 2,9-Bis[(substituted-aminomethyl)phenyl]-1,10-phenanthroline Derivatives as G-Quadruplex Ligands](https://attachments.academia-assets.com/95210129/thumbnails/1.jpg)
](ChemMedChem, 2017
Genomic sequences able to form guanine quadruplexes (G4) are found in oncogene promoters, in telo... more Genomic sequences able to form guanine quadruplexes (G4) are found in oncogene promoters, in telomeres and in 5' and 3' untranslated regions as well as introns of messenger RNAs. These regions are potential targets for drugs designed to treat cancer. In the present work, we present the design and syntheses of ten new phenantroline derivatives and characterization of their interactions with G4-forming oligonucleotides. We evaluated ligand-induced stabilization and specificity and selectivity of ligands for various G4 conformations using FRET-melting experiments. We investigated the interaction of compound 1a, which combined the greatest stabilising effect and specificity for G4, with human telomeric sequences using FRET, circular dichroism and ESI-MS. In addition, we showed that compound 1a interferes with the G4 helicase activity of Saccharomyces cerevisiae Pif1. Interestingly, compound 1a was significantly more cytotoxic toward two human leukemic cell lines than to normal human blood mononuclear cells. These novel phenantroline derivatives will be a starting point for further development and optimization of potent G4 ligands that have potential as anti-cancer agents.
Journal of Biological Chemistry, 2016
The replication protein A (RPA) is a single-stranded DNA binding protein that plays an essential ... more The replication protein A (RPA) is a single-stranded DNA binding protein that plays an essential role in DNA metabolism. RPA is able to unfold G-quadruplex (G4) structures formed by telomeric DNA sequences, a function important for telomere maintenance. To elucidate mechanism through which RPA unfolds telomeric G4s, we studied its interaction with oligonucleotides that adopt a G4 structure extended with a single-stranded tail on either side of the G4. Binding and unfolding was characterized using several biochemical and biophysical approaches and in the presence of specific G4 ligands, such as telomestatin and 360A. Our data show that RPA can bind on each side of the G4 but it unwinds the G4 only from 5' toward 3'. We explain the 5' to 3' unfolding directionality in terms of the 5' to 3' oriented laying-out of hRPA subunits along single-stranded DNA. Furthermore we demonstrate by kinetics experiments that RPA proceeds with the same directionality for duplex unfolding.
Antecedentes historicos de la vulneracion del acceso a la Justicia—Recurso de amparo como medio d... more Antecedentes historicos de la vulneracion del acceso a la Justicia—Recurso de amparo como medio de tutela del Derecho de acceso a la Justicia-- Aspectos doctrinarios sobre la Vulneracion al Acceso a la Justicia en la normativa juridica Internacional sobre Derechos Humanos-- Analisis de resoluciones de amparo.
Data in Brief, 2015
This article describes additional data related to a research article entitled "Kinetics of Quadru... more This article describes additional data related to a research article entitled "Kinetics of Quadruplex to Duplex Conversion" (Mendoza et al. 2015 [1]). We followed the opening reaction of a series of intramolecular G-quadruplex structures by the addition of their corresponding complementary strand. Fluorolabeled complementary strands allowed to monitor the reaction in real-time. An adapted kinetic model was then applied in order to obtain the kinetic parameters of this reaction. We present a series of kinetic traces providing raw data of the G4 opening reaction and the fitting model applied in every case. In addition CD spectra and UV melting data is also provided to confirm the stability of all the DNA structures considered (G-quadruplex and duplex DNA).
Revista Facultad de Ingeniería
In this paper we present a Model Predictive Controller (MPC) implemented in a rice drying process... more In this paper we present a Model Predictive Controller (MPC) implemented in a rice drying process with inclined silo. A pilot system is used at scale of 1:10, and capacity of 25 kg. In this system temperature and humidity of the rice grains are measured as well as air humidity. Additionally, the flow and temperature of drying air are controlled and measured. In order to design the controller a model based on thin layer and physical first principles is obtained and validated. Then, a MPC controller is designed based on this model. The type of MPC controller used is Dynamic Matrix Control (DMC) which uses Diseño e implementación de una estrategia de control predictivo para el secado de arroz paddy the system step and free responses to estimate the next optimal control input. As a result, a good performance of the controller is obtained, showing that this is a promising technology that can be used in the Paddy rice drying process. The results show improvements in: a) reduction in dryin...
Cement and Concrete Research, 2015
This research evaluates the effect of sodium and potassium hydroxide on the structure and nano-me... more This research evaluates the effect of sodium and potassium hydroxide on the structure and nano-mechanical properties of Calcium Silicate Hydrate (C-S-H) formed from the hydration of pure alite. Monoclinic (MIII) alite was synthesized and hydrated, using water-to-alite ratios of 0.5 and 0.6 and additions of 10% NaOH and KOH by weight of alite. Based on results of X-ray diffraction, isothermal calorimetry, thermogravimetric analysis, Nuclear Magnetic Resonance and nanoindentation, two different effects of the alkaline hydroxides on the hydration reaction of alite, both at early and later ages, can be identified: (i) a differentiated hydration process, attributed to an enhancement in calcium hydroxide (CH) precipitation and a stimulation of the C-S-H nuclei; and (ii) an increase in the elastic modulus of the C-S-H aggregations, attributed to an electrostatic attraction between positive charges from the alkaline cations and negative charges from the C-S-H structure.
Chemistry - A European Journal, 2015
DNA and RNA G-quadruplexes (G4) are unusual nucleic acid structures involved in a number of key b... more DNA and RNA G-quadruplexes (G4) are unusual nucleic acid structures involved in a number of key biological processes. RNA G-quadruplexes are less studied although recent evidence demonstrates that they are biologically relevant. Compared to DNA quadruplexes, RNA G4 are generally more stable and less polymorphic. Duplexes and quadruplexes may be combined to obtain pure tetrameric species. Here, we investigated whether classical antiparallel duplexes can drive the formation of antiparallel tetramolecular quad-ruplexes. This concept was first successfully applied to DNA G4. In contrast, RNA G4 were found to be much more unwilling to adopt the forced antiparallel orientation, highlighting that the reason RNA adopts a different structure must not be sought in the loops but in the G-stem structure itself. RNA antiparallel G4 formation is likely to be restricted to a very small set of peculiar sequences, in which other structural features overcome the formidable intrinsic barrier preventing its formation.
Nucleic acids research, Jan 12, 2015
Helicases, enzymes that unwind DNA or RNA structure, are present in the cell nucleus and in the m... more Helicases, enzymes that unwind DNA or RNA structure, are present in the cell nucleus and in the mitochondrion. Although the majority of the helicases unwind DNA or RNA duplexes, some of these proteins are known to resolve unusual structures such as G-quadruplexes (G4) in vitro. G4 may form stable barrier to the progression of molecular motors tracking on DNA. Monitoring G4 unwinding by these enzymes may reveal the mechanisms of the enzymes and provides information about the stability of these structures. In the experiments presented herein, we developed a reliable, inexpensive and rapid fluorescence-based technique to monitor the activity of G4 helicases in real time in a 96-well plate format. This system was used to screen a series of G4 structures and G4 binders for their effect on the Pif1 enzyme, a 5' to 3' DNA helicase. This simple assay should be adaptable to analysis of other helicases and G4 structures.
Revista Veterinaria, 2021
El salazonado de pescado es una forma antigua y económica de preservación que se usa aún en paíse... more El salazonado de pescado es una forma antigua y económica de preservación que se usa aún en países en vías de desarrollo como el Perú. En la región Tumbes, es común la comercialización de caballa (Scomber japonicus peruanus) salada artesanalmente, por lo cual su inocuidad microbiológica no está garantizada. La presente investigación tuvo como objetivo identificar, mediante el secuenciamiento de un fragmento del gen 16S ARNr, las bacterias cultivables presente en la caballa salada comercializada en Tumbes. A partir de tejido del músculo de la caballa, se aislaron cepas bacterianas en medio TSA suplementado con 15% de NaCl, de las que luego se obtuvieron fragmentos del gen 16S ARNr, que fueron secuenciados para luego identificar la especie a la que pertenecieron mediante una búsqueda en Genbank. Adicionalmente se analizaron el contenido de humedad y de NaCl del músculo de la caballa salada. Como resultado se identificaron cepas típicas de productos salados como: Staphylococcus sp, Hal...
Revista de Investigaciones Veterinarias del Perú, 2021
El objetivo de la presente investigación fue aislar, seleccionar y caracterizar genéticamente bac... more El objetivo de la presente investigación fue aislar, seleccionar y caracterizar genéticamente bacterias nativas de Argopecten purpuratus que, a través de un biofilm, estimulen su asentamiento larval. Conociendo que el asentamiento larval es el principal problema que afronta la reproducción en laboratorio de este molusco, se utilizó un biofilm bacteriano para mejorar porcentualmente la fijación larval. Se aislaron cepas bacterianas nativas del cultivo de A. purpuratus y se caracterizaron taxonómicamente a partir del análisis de las secuencias parciales del gen 16S rARN, amplificadas mediante PCR a cada una de las muestras de ADN extraídas de las cepas bacterianas aisladas. Al analizar las secuencias se identificó a nivel de género tres cepas bacterianas; Oceanobacillus, Bacillus y Pseudomonas. Además, se avaluó la eficiencia de fijación de larvas de A. purpuratus en los biofilms formados por las cepas Oceanobacillus y Bacillus logrando una fijación de 12 y 14%, en tanto que al estar ...
This project was developed by the opportunity that nowadays sports, especially football has gone ... more This project was developed by the opportunity that nowadays sports, especially football has gone from being a simple way to exercise and demonstrate skills to a business investment. Here works basically 2 areas: The Football Soccer as a sport and recreation, and the latter establishments commonly known as "synthetic grass courts." In Ecuador there are several places that offer hourly rental synthetic grass courts allowing playing football in a nice place to assist with who handle the same affinity and set up matches with friends or co-workers and even complete Championships. In the Canton General Villamil Playas, a large proportion of the population practice football but in conditions which are not nice nor proper to practice, and there are only two football fields, which are used to organize parties and championships but this is insufficient to meet the demand for people who enjoy this sport This is the reason why it is necessary to create a project focused on the constru...
COMPRA RAPIDO was born from an idea of three young entrepreneurs who seek to provide a different ... more COMPRA RAPIDO was born from an idea of three young entrepreneurs who seek to provide a different kind of online service, which is an important and necessary in this era where technology goes hand in hand with the daily lives of people. Is aimed at businesses, homes, in which it is difficult to go to the supermarket to choose the products you are interested, so, our website offers the convenience of getting them quickly. Provide service to make grocery shopping online. Our company offers the products on the market in a different way because of the facilities offered in the types of delivery schedule availability, affordability, etc.
Discovery Fiesta Cruises is a maritime craft that devotes itself to give the service of fluvial t... more Discovery Fiesta Cruises is a maritime craft that devotes itself to give the service of fluvial tourism. The company was founded in 1991. Nowadays there is rolled in the “Malecon Simon Bolivar” of the city of Guayaquil, where the first
Presentamos resultados de una investigacion relacionada con el aprendizaje de las soluciones de s... more Presentamos resultados de una investigacion relacionada con el aprendizaje de las soluciones de sistemas de ecuaciones lineales (SEL 2x2) consistentes e inconsistentes, a traves de conversiones entre los registros: verbal, algebraico-simbolico y grafico y tratamiento en ellos con el apoyo de software (e.g., GeoGebra). Los datos fueron analizados por tres conceptos los cuales obtuvimos de confluir las teorias Cambio de atencion y Representaciones semioticas . En el estudio participaron 25 estudiantes de nivel superior de entre 19 y 23 anos. La metodologia fue de tipo cualitativo. Se describen las respuestas de dos equipos al resolver tres problemas. Los resultados indican que los equipos lograron resolver los problemas asociados a SEL 2x2 consistentes con solucion unica, mediante la conversion entre el registro verbal y el registro grafico, pero tuvieron dificultades al resolver los problemas asociados a SEL 2x2 inconsistentes y consistentes con infinidad de soluciones.
Manglar, 2015
Crecimiento y supervivencia de Anadara tuberculosa (Sowerby, 1833) a tres densidades Growth and s... more Crecimiento y supervivencia de Anadara tuberculosa (Sowerby, 1833) a tres densidades Growth and survival of Anadara tuberculosa (Sowerby, 1833) on three densities
Revista Repertorio de Medicina y Cirugía, 2018
Para la Sociedad de Cirugía de Bogotá, Hospital de San José, es un honor haber contado con la pre... more Para la Sociedad de Cirugía de Bogotá, Hospital de San José, es un honor haber contado con la presencia del doctor Josep Brugada en el marco del Segundo Simposio SDC, muerte súbita cardiovascular, del proyecto PR-Chagas, financiado por Colciencias y organizado en conjunto con docentes de la Fundación Universitaria de Ciencias de la Salud. La enfermedad de Chagas es una de las enfermedades transmitidas por vectores de mayor importancia en salud pública en el país, en especial por las manifestaciones de la fase crónica que afectan al corazón. El vector de la enfermedad es el triatómino, un tipo de insecto hematófago que se encuentra distribuido en diferentes regiones de nuestro país, poniendo en riesgo de padecer la infección a cerca de 8 millones de nuestros compatriotas generando una importante prevalencia de la miocardiopatía chagásica en diversos departamentos, siendo acorde con estadísticas de la Organización Mundial de la Salud que estima en cerca de 10 millones las personas inf...
INGENIERÍA Y COMPETITIVIDAD, 1970
Este trabajo considera un exoesqueleto de miembros inferiores actuado en cadera y rodilla, con to... more Este trabajo considera un exoesqueleto de miembros inferiores actuado en cadera y rodilla, con torso y pies de apoyo portando un maniquí; se presenta el diseño e implementación de una estrategia de control para el equilibrio estático del exoesqueleto-maniquí, consistente en un control distribuido de bajo nivel para el posicionamiento angular de las articulaciones y de un control centralizado de alto nivel para el equilibrio. Para el control de posicionamiento angular en las articulaciones actuadas se diseñaron controladores PID; este control permite el seguimiento de trayectorias de posición en las articulaciones, preestablecidas por la estrategia de control de alto nivel. A partir del cálculo de la desviación horizontal del centro de masa del sistema total, el control de equilibrio estático manipula las articulaciones para compensar los disturbios de pequeña señal en la postura del exoesqueleto-maniquí. Se establece un protocolo para obtener los parámetros de la ley de control y la...
Biochimica et biophysica acta, May 6, 2017
G-quadruplexes (G4) are RNA and DNA secondary structures formed by the stacking of guanine quarte... more G-quadruplexes (G4) are RNA and DNA secondary structures formed by the stacking of guanine quartets in guanine rich sequences. Quadruplex-prone motifs may be found in key genomic regions such as telomeres, ribosomal DNA, transcriptional activators and regulators or oncogene promoters. A number of proteins involved in various biological processes are able to interact with G4s. Among them, proteins dedicated to nucleic acids unwinding such as WRN, BLM, FANCJ or PIF1, can unfold G4 structures. Mutations of these helicases are linked to genome instability and to increases in cancer risks. Here, we present a high-throughput fluorescence-based reliable, inexpensive and fast assay to study G4/RHAU interaction. RHAU is an RNA helicase known as the major source of G4 resolution in HeLa cells. Our assay allows to monitor the unfolding properties of RHAU towards DNA and RNA quadruplexes in parallel and to screen for the optimal conditions for its activity. This article is part of a Special Iss...
The Journal of chemical physics, Jan 14, 2017
Logic circuits based on DNA strand displacement reaction are the basic building blocks of future ... more Logic circuits based on DNA strand displacement reaction are the basic building blocks of future nanorobotic systems. The circuits tethered to DNA origami platforms present several advantages over solution-phase versions where couplings are always diffusion-limited. Here we consider a possible implementation of one of the basic operations needed in the design of these circuits, namely, signal replication. We show that with an appropriate preparation of the initial state, signal replication performs in a reproducible way. We also show the existence of side effects concomitant to the high effective concentrations in tethered circuits, such as slow leaky reactions and cross-activation.
ChemMedChem, 2017
Genomic sequences able to form guanine quadruplexes (G4) are found in oncogene promoters, in telo... more Genomic sequences able to form guanine quadruplexes (G4) are found in oncogene promoters, in telomeres and in 5' and 3' untranslated regions as well as introns of messenger RNAs. These regions are potential targets for drugs designed to treat cancer. In the present work, we present the design and syntheses of ten new phenantroline derivatives and characterization of their interactions with G4-forming oligonucleotides. We evaluated ligand-induced stabilization and specificity and selectivity of ligands for various G4 conformations using FRET-melting experiments. We investigated the interaction of compound 1a, which combined the greatest stabilising effect and specificity for G4, with human telomeric sequences using FRET, circular dichroism and ESI-MS. In addition, we showed that compound 1a interferes with the G4 helicase activity of Saccharomyces cerevisiae Pif1. Interestingly, compound 1a was significantly more cytotoxic toward two human leukemic cell lines than to normal human blood mononuclear cells. These novel phenantroline derivatives will be a starting point for further development and optimization of potent G4 ligands that have potential as anti-cancer agents.
Journal of Biological Chemistry, 2016
The replication protein A (RPA) is a single-stranded DNA binding protein that plays an essential ... more The replication protein A (RPA) is a single-stranded DNA binding protein that plays an essential role in DNA metabolism. RPA is able to unfold G-quadruplex (G4) structures formed by telomeric DNA sequences, a function important for telomere maintenance. To elucidate mechanism through which RPA unfolds telomeric G4s, we studied its interaction with oligonucleotides that adopt a G4 structure extended with a single-stranded tail on either side of the G4. Binding and unfolding was characterized using several biochemical and biophysical approaches and in the presence of specific G4 ligands, such as telomestatin and 360A. Our data show that RPA can bind on each side of the G4 but it unwinds the G4 only from 5' toward 3'. We explain the 5' to 3' unfolding directionality in terms of the 5' to 3' oriented laying-out of hRPA subunits along single-stranded DNA. Furthermore we demonstrate by kinetics experiments that RPA proceeds with the same directionality for duplex unfolding.
Antecedentes historicos de la vulneracion del acceso a la Justicia—Recurso de amparo como medio d... more Antecedentes historicos de la vulneracion del acceso a la Justicia—Recurso de amparo como medio de tutela del Derecho de acceso a la Justicia-- Aspectos doctrinarios sobre la Vulneracion al Acceso a la Justicia en la normativa juridica Internacional sobre Derechos Humanos-- Analisis de resoluciones de amparo.
Data in Brief, 2015
This article describes additional data related to a research article entitled "Kinetics of Quadru... more This article describes additional data related to a research article entitled "Kinetics of Quadruplex to Duplex Conversion" (Mendoza et al. 2015 [1]). We followed the opening reaction of a series of intramolecular G-quadruplex structures by the addition of their corresponding complementary strand. Fluorolabeled complementary strands allowed to monitor the reaction in real-time. An adapted kinetic model was then applied in order to obtain the kinetic parameters of this reaction. We present a series of kinetic traces providing raw data of the G4 opening reaction and the fitting model applied in every case. In addition CD spectra and UV melting data is also provided to confirm the stability of all the DNA structures considered (G-quadruplex and duplex DNA).
Revista Facultad de Ingeniería
In this paper we present a Model Predictive Controller (MPC) implemented in a rice drying process... more In this paper we present a Model Predictive Controller (MPC) implemented in a rice drying process with inclined silo. A pilot system is used at scale of 1:10, and capacity of 25 kg. In this system temperature and humidity of the rice grains are measured as well as air humidity. Additionally, the flow and temperature of drying air are controlled and measured. In order to design the controller a model based on thin layer and physical first principles is obtained and validated. Then, a MPC controller is designed based on this model. The type of MPC controller used is Dynamic Matrix Control (DMC) which uses Diseño e implementación de una estrategia de control predictivo para el secado de arroz paddy the system step and free responses to estimate the next optimal control input. As a result, a good performance of the controller is obtained, showing that this is a promising technology that can be used in the Paddy rice drying process. The results show improvements in: a) reduction in dryin...
Cement and Concrete Research, 2015
This research evaluates the effect of sodium and potassium hydroxide on the structure and nano-me... more This research evaluates the effect of sodium and potassium hydroxide on the structure and nano-mechanical properties of Calcium Silicate Hydrate (C-S-H) formed from the hydration of pure alite. Monoclinic (MIII) alite was synthesized and hydrated, using water-to-alite ratios of 0.5 and 0.6 and additions of 10% NaOH and KOH by weight of alite. Based on results of X-ray diffraction, isothermal calorimetry, thermogravimetric analysis, Nuclear Magnetic Resonance and nanoindentation, two different effects of the alkaline hydroxides on the hydration reaction of alite, both at early and later ages, can be identified: (i) a differentiated hydration process, attributed to an enhancement in calcium hydroxide (CH) precipitation and a stimulation of the C-S-H nuclei; and (ii) an increase in the elastic modulus of the C-S-H aggregations, attributed to an electrostatic attraction between positive charges from the alkaline cations and negative charges from the C-S-H structure.
Chemistry - A European Journal, 2015
DNA and RNA G-quadruplexes (G4) are unusual nucleic acid structures involved in a number of key b... more DNA and RNA G-quadruplexes (G4) are unusual nucleic acid structures involved in a number of key biological processes. RNA G-quadruplexes are less studied although recent evidence demonstrates that they are biologically relevant. Compared to DNA quadruplexes, RNA G4 are generally more stable and less polymorphic. Duplexes and quadruplexes may be combined to obtain pure tetrameric species. Here, we investigated whether classical antiparallel duplexes can drive the formation of antiparallel tetramolecular quad-ruplexes. This concept was first successfully applied to DNA G4. In contrast, RNA G4 were found to be much more unwilling to adopt the forced antiparallel orientation, highlighting that the reason RNA adopts a different structure must not be sought in the loops but in the G-stem structure itself. RNA antiparallel G4 formation is likely to be restricted to a very small set of peculiar sequences, in which other structural features overcome the formidable intrinsic barrier preventing its formation.
Nucleic acids research, Jan 12, 2015
Helicases, enzymes that unwind DNA or RNA structure, are present in the cell nucleus and in the m... more Helicases, enzymes that unwind DNA or RNA structure, are present in the cell nucleus and in the mitochondrion. Although the majority of the helicases unwind DNA or RNA duplexes, some of these proteins are known to resolve unusual structures such as G-quadruplexes (G4) in vitro. G4 may form stable barrier to the progression of molecular motors tracking on DNA. Monitoring G4 unwinding by these enzymes may reveal the mechanisms of the enzymes and provides information about the stability of these structures. In the experiments presented herein, we developed a reliable, inexpensive and rapid fluorescence-based technique to monitor the activity of G4 helicases in real time in a 96-well plate format. This system was used to screen a series of G4 structures and G4 binders for their effect on the Pif1 enzyme, a 5' to 3' DNA helicase. This simple assay should be adaptable to analysis of other helicases and G4 structures.