Heterogeneous enzymatic assays (HEA), where an enzyme in solution acts upon an immobilized substr... more Heterogeneous enzymatic assays (HEA), where an enzyme in solution acts upon an immobilized substrate, are been increasingly used. Given their high throughput and versatility they hold great potential for developing massive enzyme inhibitor screening. However, current HEA lack, in general, rigorous quantitative use. This is in part due to technical problems as a multiplicity of suboptimal substrate populations achieved with traditional immobilization techniques but, more importantly, is due to a poor understanding of the particular kinetic behavior of these systems. This paper addresses the kinetic features of HEA that arise from the very low amount of solid-phase substrate and the resulting inalterability of the free enzyme concentration during the assay, which classify HEA as enzyme quasi-saturable systems (EQSS). We assessed the optimal enzyme concentration working range and time of reaction. We also considered certain attributes of HEA for evaluating isosteric inhibitors. These studies were done on the basis of a simplified model for the kinetics of EQSS and a formal splitting of the functional factor of the analytical sensitivity of an enzymatic assay into [E o ]/K mdependent and temporal components.
ABSTRACT The Middle America trench is formed by the subduction of the Cocos and Rivera plates und... more ABSTRACT The Middle America trench is formed by the subduction of the Cocos and Rivera plates under the Caribbean and North American plates. The subduction interface presents low coupling in Central America showing its seismicity a high frequency of outer-rise normal fault earthquakes. These outer-rise earthquakes are generated on the inherited structures of the seafloor-spreading fabric during the subducting plate bending. We analyze focal mechanism data in combination with the available structural data of the outer-rise normal faults in order to constrain the rupture characteristics of the outer-rise normal earthquakes. A new empirical scaling relationship is developed to define earthquake magnitudes from normal fault dimensions in the outer-rise context. We numerically model the tsunami wave propagation due to the worst outer-rise tsunamigenic source in the area to estimate its damaging potential. Wave elevations higher than 2 m are common at the coast in front of the fault extent, with maximum wave elevations of 8 m. The capability of these faults to generate ocean-wide tsunamis is low, however, they can produce significant tsunamis locally.
Artículo original / original article / Artigo original 1Licenciada en Biología y Química, Magíste... more Artículo original / original article / Artigo original 1Licenciada en Biología y Química, Magíster en Ciencias-Química. Docente Instituto Tecnológico Metropolitano, ITM. 2Química. Magíster en Ciencia-Química. Docente Instituto Tecnológico Metropolitano, ITM. 3Química. Candidata a Magíster en Gestión Energética Industrial. Docente Instituto Tecnológico Metropolitano, ITM. 4Ingeniero Químico. Candidato a Magíster en Ciencias-Química. Docente Instituto Tecnológico Metropolitano, ITM. 5Ingeniero Químico. Magíster en Ciencias-Química. Docente Instituto Tecnológico Metropolitano, ITM. 6Químico. Candidato a Magíster en Ciencias-Química. Docente Instituto Tecnológico Metropolitano, ITM. Correspondencia: Adriana María Soto.
... 5. Innovación y desarrollo tecnológico participativo para la agricultura más limpia y sosteni... more ... 5. Innovación y desarrollo tecnológico participativo para la agricultura más limpia y sostenible del cultivo de arveja (Pisum sativum) en los Municipios de Samacá, Viracachá, Ciénega y Ramiriquí, en el departamento de ... En: Machado, A. (ed.). La academia y el sector rural. ...
This work presents a validation of wave parameters from the new sixty years Downscaled Ocean Wave... more This work presents a validation of wave parameters from the new sixty years Downscaled Ocean Waves (DOW) reanalysis database. This study compares quantiles of the Gumbel distribution of Hs (significant wave height) and Tp (peak period) from simulated data with an 11 months' time series obtained from a buoy moored seaward on the Santa Catarina coast. Analysis by means of Gumbel distribution quantiles allows more weight to be given to the highest values of the time series, which are especially important in design projects. The statistical parameters used to verify the fit between the measured and the modeled data included: RMSE, BIAS, Scatter Index and Pearson Correlation Coefficient. Mean direction (θm) validation was conducted qualitatively. The database showed good fit of the mean conditions, especially Hs which was well reproduced by the wave model. Underestimation of Tp, related mainly to the low spatial and temporal resolution of wind data used to generate waves, highlights this general modeling problem. Based on calculated statistical parameters, DOW data were considered comparable to the values obtained by measurements; however, such data must be cautiously used for extreme events analysis and in areas of bimodal sea conditions, where major deficiencies in the database were observed.
Journal of Pharmaceutical and Biomedical Analysis, 2004
The emergence and worldwide spreading of Plasmodium falciparum strains that shown to be resistant... more The emergence and worldwide spreading of Plasmodium falciparum strains that shown to be resistant to traditional drugs is considered a very serious health problem, given the high mortality and morbidity rate of Malaria. In the search for new drugs against this parasite, Hb hydrolyzing enzymes, such as Plasmepsin II (Plm II), have been classified as very promising targets for therapeutic attacks. In this work, it is developed a cheap and high-throughput heterogeneous enzymatic assay for measuring Plasmepsin II activity in order to use it as a tool in the discovery of new inhibitors of this enzyme. In this assay, Plasmepsin II acts upon a solid-phase bound synthetic peptide (DU2) whose sequence comprises the cleavage site F 33 -L 34 present in Hb ␣-chain. The peptide surface density is quantified by means of a classical ELISA-based procedure. In order to estimate the kinetic constants of the system and to quantify both, enzymatic and inhibitory activity, it was used a model for the kinetics of enzyme quasi-saturable systems previously developed by our group, that fitted very well to the experimental data. It was used Pepstatin as a model inhibitor of Plasmepsin II and the resulting dose-response relation agreed with the expected behavior for the Pepstatin-Plasmepsin II pair under the employed experimental conditions.
Vitroceramic powders of Li 2 O-Al 2 O 3 -SiO 2 systems (LAS), doped with 1% (LAS:1Ce) and 10% (LA... more Vitroceramic powders of Li 2 O-Al 2 O 3 -SiO 2 systems (LAS), doped with 1% (LAS:1Ce) and 10% (LAS:10Ce) molar of cerianite (CeO 2 ) were synthesized by means of the gelification technique of metal formates of aluminum and lithium, in the presence of tetraethoxy silane and CeO 2 . The gels obtained were dried (120 1C, 2.5 h), calcined (480 1C, 5 h) and sinterized (1250 1C, 30 min). The sinterized samples were characterized by X-ray difraction (XRD), scanning electron microscopy (SEM) and microchemical analysis (EDS). There is evidence for a mixture of two phases of 64% b-spodumene (Li 2 O-Al 2 O 3 -4SiO 2 ) and 36% b-eucryptite (Li 2 O-Al 2 O 3 -2SiO 2 ). The LAS:1Ce system was enriched in aluminum, the LAS:10Ce system showed areas of heterogeneous composition; some regions with a shortage of CeO 2 , while others zones with cerium cumulus. From the microscopy images it was found that CeO 2 acts as a densificant agent in LAS system, favoring the sintering in the host. The chemical route and the sintering processes utilized allow the production of samples exhibiting an acceptable linear correlation between total thermoluminescent emission intensity and the irradiation dose when the CeO 2 concentration is low (less than 1%), opening the possibility of using this kind of glass-ceramic in dosimetry.
A comparative study of the thermoluminescence (TL) emission between beta-irradiated lithium alumi... more A comparative study of the thermoluminescence (TL) emission between beta-irradiated lithium aluminosilicates, Li 2 O-Al 2 O 3 -SiO 2 (LAS), and beta-irradiated CeO 2 -doped lithium aluminosilicates, Li 2 O-Al 2 O 3 -SiO 2 -CeO 2 (LAS:Ce), grown by sol-gel technique and preannealed at 1250 1C is presented. It is found that doping reinforces the result of preannealing the sample; the incorporation of CeO 2 at low concentrations shifts the TL curves towards higher temperatures and increases the total intensity with respect to samples without the dopant. This behavior, together with the fact that CeO 2 is a good densification agent, suggests the possibility of using CeO 2 to improve the technological properties of LAS. Deconvolution analysis of the thermoluminescence glow curves of doped materials under general order kinetics shows that the relevant temperatures at which the component signals appear are virtually the same as for pure samples. This suggests that CeO 2 does not introduce new types of traps, but only changes the population and distribution of impurities responsible for the TL in the original matrix of LAS. Finally, the kinetic parameters for the deconvoluted curves are reported. They corroborate that changes in CeO 2 concentration only vary the depth and distribution of the same kind of original traps.
Cochaperones are important for the folding and activation of steroid hormone receptors. Results: ... more Cochaperones are important for the folding and activation of steroid hormone receptors. Results: The androgen receptor-associated cochaperone SGTA binds both Hsp70 and Hsp90 and regulates progesterone and glucocorticoid receptors. Conclusion: SGTA is a receptor-specific cochaperone that regulates distinct steps in the receptor chaperoning cycle. Significance: SGTA is a relevant factor in diseases that depend on androgens, progestins and/or glucocorticoids.
Nod2, a member of the Apaf1/Nod protein family, confers responsiveness to bacterial products and ... more Nod2, a member of the Apaf1/Nod protein family, confers responsiveness to bacterial products and activates NF-B, a transcription factor that plays a central role in innate immunity. Recently, genetic variation in Nod2 has been associated with susceptibility to Crohn's disease. Here, we report that expression of Nod2 is induced upon differentiation of CD34 ؉ hematopoietic progenitor cells into granulocyte or monocyte/macrophages. In peripheral blood cells, the highest levels of Nod2 were observed in CD14 ؉ (monocytes), CD15 ؉ (granulocytes), and CD40 ؉ /CD86 ؉ (dendritic cells) cell populations. Notably, stimulation of myeloblastic and epithelial cells with bacterial lipopolysaccharide or TNF␣ resulted in up-regulation of Nod2. A search for consensus sites within the Nod2 promoter revealed a NF-B binding element that was required for transcriptional activity in response to TNF␣. Moreover, ectopic expression of p65 induced transactivation, whereas that of dominant-negative IB␣ blocked the transcriptional activity of the Nod2 promoter. Upon stimulation with TNF␣ or lipopolysaccharide, both p50 and p65 subunits of NF-B were bound to the Nod2 promoter. Thus, Nod2 expression is enhanced by proinflammatory cytokines and bacterial components via NF-B, a mechanism that may contribute to the amplification of the innate immune response and susceptibility to inflammatory disease.
Proline-and acid-rich (PAR) basic region leucine zipper (bZIP) proteins thyrotroph embryonic fact... more Proline-and acid-rich (PAR) basic region leucine zipper (bZIP) proteins thyrotroph embryonic factor (TEF), D-sitebinding protein (DBP), and hepatic leukemia factor have been involved in neurotransmitter homeostasis and amino acid metabolism. Here we demonstrate a novel role for these proteins in the transcriptional control of a BH3-only gene. PAR bZIP proteins are able to transactivate the promoter of bcl-gS.
Tripeptidyl-peptidase II (TPP II) is a cytosolic peptidase that has been implicated in fat format... more Tripeptidyl-peptidase II (TPP II) is a cytosolic peptidase that has been implicated in fat formation and cancer, apparently independent of the enzymatic activity. In search for alternative functional regions, conserved motifs were identified and eleven signatures were constructed. Seven of the signatures covered previously investigated residues, whereas the functional importance of the other motifs is unknown. This provides directions for future investigations of alternative activities of TPP II. The obtained signatures provide an efficient bioinformatic tool for the identification of TPP II homologues. Hence, a TPP II sequence homologue from fission yeast, Schizosaccharomyces pombe, was identified and demonstrated to encode the TPP II-like protein previously reported as multicorn. Furthermore, an homologous protein was found in the prokaryote Blastopirellula marina, albeit the TPP II function was apparently not conserved. This gene is probably the result of a rare gene transfer from eukaryote to prokaryote.
Heterogeneous enzymatic assays (HEA), where an enzyme in solution acts upon an immobilized substr... more Heterogeneous enzymatic assays (HEA), where an enzyme in solution acts upon an immobilized substrate, are been increasingly used. Given their high throughput and versatility they hold great potential for developing massive enzyme inhibitor screening. However, current HEA lack, in general, rigorous quantitative use. This is in part due to technical problems as a multiplicity of suboptimal substrate populations achieved with traditional immobilization techniques but, more importantly, is due to a poor understanding of the particular kinetic behavior of these systems. This paper addresses the kinetic features of HEA that arise from the very low amount of solid-phase substrate and the resulting inalterability of the free enzyme concentration during the assay, which classify HEA as enzyme quasi-saturable systems (EQSS). We assessed the optimal enzyme concentration working range and time of reaction. We also considered certain attributes of HEA for evaluating isosteric inhibitors. These studies were done on the basis of a simplified model for the kinetics of EQSS and a formal splitting of the functional factor of the analytical sensitivity of an enzymatic assay into [E o ]/K mdependent and temporal components.
ABSTRACT The Middle America trench is formed by the subduction of the Cocos and Rivera plates und... more ABSTRACT The Middle America trench is formed by the subduction of the Cocos and Rivera plates under the Caribbean and North American plates. The subduction interface presents low coupling in Central America showing its seismicity a high frequency of outer-rise normal fault earthquakes. These outer-rise earthquakes are generated on the inherited structures of the seafloor-spreading fabric during the subducting plate bending. We analyze focal mechanism data in combination with the available structural data of the outer-rise normal faults in order to constrain the rupture characteristics of the outer-rise normal earthquakes. A new empirical scaling relationship is developed to define earthquake magnitudes from normal fault dimensions in the outer-rise context. We numerically model the tsunami wave propagation due to the worst outer-rise tsunamigenic source in the area to estimate its damaging potential. Wave elevations higher than 2 m are common at the coast in front of the fault extent, with maximum wave elevations of 8 m. The capability of these faults to generate ocean-wide tsunamis is low, however, they can produce significant tsunamis locally.
Artículo original / original article / Artigo original 1Licenciada en Biología y Química, Magíste... more Artículo original / original article / Artigo original 1Licenciada en Biología y Química, Magíster en Ciencias-Química. Docente Instituto Tecnológico Metropolitano, ITM. 2Química. Magíster en Ciencia-Química. Docente Instituto Tecnológico Metropolitano, ITM. 3Química. Candidata a Magíster en Gestión Energética Industrial. Docente Instituto Tecnológico Metropolitano, ITM. 4Ingeniero Químico. Candidato a Magíster en Ciencias-Química. Docente Instituto Tecnológico Metropolitano, ITM. 5Ingeniero Químico. Magíster en Ciencias-Química. Docente Instituto Tecnológico Metropolitano, ITM. 6Químico. Candidato a Magíster en Ciencias-Química. Docente Instituto Tecnológico Metropolitano, ITM. Correspondencia: Adriana María Soto.
... 5. Innovación y desarrollo tecnológico participativo para la agricultura más limpia y sosteni... more ... 5. Innovación y desarrollo tecnológico participativo para la agricultura más limpia y sostenible del cultivo de arveja (Pisum sativum) en los Municipios de Samacá, Viracachá, Ciénega y Ramiriquí, en el departamento de ... En: Machado, A. (ed.). La academia y el sector rural. ...
This work presents a validation of wave parameters from the new sixty years Downscaled Ocean Wave... more This work presents a validation of wave parameters from the new sixty years Downscaled Ocean Waves (DOW) reanalysis database. This study compares quantiles of the Gumbel distribution of Hs (significant wave height) and Tp (peak period) from simulated data with an 11 months' time series obtained from a buoy moored seaward on the Santa Catarina coast. Analysis by means of Gumbel distribution quantiles allows more weight to be given to the highest values of the time series, which are especially important in design projects. The statistical parameters used to verify the fit between the measured and the modeled data included: RMSE, BIAS, Scatter Index and Pearson Correlation Coefficient. Mean direction (θm) validation was conducted qualitatively. The database showed good fit of the mean conditions, especially Hs which was well reproduced by the wave model. Underestimation of Tp, related mainly to the low spatial and temporal resolution of wind data used to generate waves, highlights this general modeling problem. Based on calculated statistical parameters, DOW data were considered comparable to the values obtained by measurements; however, such data must be cautiously used for extreme events analysis and in areas of bimodal sea conditions, where major deficiencies in the database were observed.
Journal of Pharmaceutical and Biomedical Analysis, 2004
The emergence and worldwide spreading of Plasmodium falciparum strains that shown to be resistant... more The emergence and worldwide spreading of Plasmodium falciparum strains that shown to be resistant to traditional drugs is considered a very serious health problem, given the high mortality and morbidity rate of Malaria. In the search for new drugs against this parasite, Hb hydrolyzing enzymes, such as Plasmepsin II (Plm II), have been classified as very promising targets for therapeutic attacks. In this work, it is developed a cheap and high-throughput heterogeneous enzymatic assay for measuring Plasmepsin II activity in order to use it as a tool in the discovery of new inhibitors of this enzyme. In this assay, Plasmepsin II acts upon a solid-phase bound synthetic peptide (DU2) whose sequence comprises the cleavage site F 33 -L 34 present in Hb ␣-chain. The peptide surface density is quantified by means of a classical ELISA-based procedure. In order to estimate the kinetic constants of the system and to quantify both, enzymatic and inhibitory activity, it was used a model for the kinetics of enzyme quasi-saturable systems previously developed by our group, that fitted very well to the experimental data. It was used Pepstatin as a model inhibitor of Plasmepsin II and the resulting dose-response relation agreed with the expected behavior for the Pepstatin-Plasmepsin II pair under the employed experimental conditions.
Vitroceramic powders of Li 2 O-Al 2 O 3 -SiO 2 systems (LAS), doped with 1% (LAS:1Ce) and 10% (LA... more Vitroceramic powders of Li 2 O-Al 2 O 3 -SiO 2 systems (LAS), doped with 1% (LAS:1Ce) and 10% (LAS:10Ce) molar of cerianite (CeO 2 ) were synthesized by means of the gelification technique of metal formates of aluminum and lithium, in the presence of tetraethoxy silane and CeO 2 . The gels obtained were dried (120 1C, 2.5 h), calcined (480 1C, 5 h) and sinterized (1250 1C, 30 min). The sinterized samples were characterized by X-ray difraction (XRD), scanning electron microscopy (SEM) and microchemical analysis (EDS). There is evidence for a mixture of two phases of 64% b-spodumene (Li 2 O-Al 2 O 3 -4SiO 2 ) and 36% b-eucryptite (Li 2 O-Al 2 O 3 -2SiO 2 ). The LAS:1Ce system was enriched in aluminum, the LAS:10Ce system showed areas of heterogeneous composition; some regions with a shortage of CeO 2 , while others zones with cerium cumulus. From the microscopy images it was found that CeO 2 acts as a densificant agent in LAS system, favoring the sintering in the host. The chemical route and the sintering processes utilized allow the production of samples exhibiting an acceptable linear correlation between total thermoluminescent emission intensity and the irradiation dose when the CeO 2 concentration is low (less than 1%), opening the possibility of using this kind of glass-ceramic in dosimetry.
A comparative study of the thermoluminescence (TL) emission between beta-irradiated lithium alumi... more A comparative study of the thermoluminescence (TL) emission between beta-irradiated lithium aluminosilicates, Li 2 O-Al 2 O 3 -SiO 2 (LAS), and beta-irradiated CeO 2 -doped lithium aluminosilicates, Li 2 O-Al 2 O 3 -SiO 2 -CeO 2 (LAS:Ce), grown by sol-gel technique and preannealed at 1250 1C is presented. It is found that doping reinforces the result of preannealing the sample; the incorporation of CeO 2 at low concentrations shifts the TL curves towards higher temperatures and increases the total intensity with respect to samples without the dopant. This behavior, together with the fact that CeO 2 is a good densification agent, suggests the possibility of using CeO 2 to improve the technological properties of LAS. Deconvolution analysis of the thermoluminescence glow curves of doped materials under general order kinetics shows that the relevant temperatures at which the component signals appear are virtually the same as for pure samples. This suggests that CeO 2 does not introduce new types of traps, but only changes the population and distribution of impurities responsible for the TL in the original matrix of LAS. Finally, the kinetic parameters for the deconvoluted curves are reported. They corroborate that changes in CeO 2 concentration only vary the depth and distribution of the same kind of original traps.
Cochaperones are important for the folding and activation of steroid hormone receptors. Results: ... more Cochaperones are important for the folding and activation of steroid hormone receptors. Results: The androgen receptor-associated cochaperone SGTA binds both Hsp70 and Hsp90 and regulates progesterone and glucocorticoid receptors. Conclusion: SGTA is a receptor-specific cochaperone that regulates distinct steps in the receptor chaperoning cycle. Significance: SGTA is a relevant factor in diseases that depend on androgens, progestins and/or glucocorticoids.
Nod2, a member of the Apaf1/Nod protein family, confers responsiveness to bacterial products and ... more Nod2, a member of the Apaf1/Nod protein family, confers responsiveness to bacterial products and activates NF-B, a transcription factor that plays a central role in innate immunity. Recently, genetic variation in Nod2 has been associated with susceptibility to Crohn's disease. Here, we report that expression of Nod2 is induced upon differentiation of CD34 ؉ hematopoietic progenitor cells into granulocyte or monocyte/macrophages. In peripheral blood cells, the highest levels of Nod2 were observed in CD14 ؉ (monocytes), CD15 ؉ (granulocytes), and CD40 ؉ /CD86 ؉ (dendritic cells) cell populations. Notably, stimulation of myeloblastic and epithelial cells with bacterial lipopolysaccharide or TNF␣ resulted in up-regulation of Nod2. A search for consensus sites within the Nod2 promoter revealed a NF-B binding element that was required for transcriptional activity in response to TNF␣. Moreover, ectopic expression of p65 induced transactivation, whereas that of dominant-negative IB␣ blocked the transcriptional activity of the Nod2 promoter. Upon stimulation with TNF␣ or lipopolysaccharide, both p50 and p65 subunits of NF-B were bound to the Nod2 promoter. Thus, Nod2 expression is enhanced by proinflammatory cytokines and bacterial components via NF-B, a mechanism that may contribute to the amplification of the innate immune response and susceptibility to inflammatory disease.
Proline-and acid-rich (PAR) basic region leucine zipper (bZIP) proteins thyrotroph embryonic fact... more Proline-and acid-rich (PAR) basic region leucine zipper (bZIP) proteins thyrotroph embryonic factor (TEF), D-sitebinding protein (DBP), and hepatic leukemia factor have been involved in neurotransmitter homeostasis and amino acid metabolism. Here we demonstrate a novel role for these proteins in the transcriptional control of a BH3-only gene. PAR bZIP proteins are able to transactivate the promoter of bcl-gS.
Tripeptidyl-peptidase II (TPP II) is a cytosolic peptidase that has been implicated in fat format... more Tripeptidyl-peptidase II (TPP II) is a cytosolic peptidase that has been implicated in fat formation and cancer, apparently independent of the enzymatic activity. In search for alternative functional regions, conserved motifs were identified and eleven signatures were constructed. Seven of the signatures covered previously investigated residues, whereas the functional importance of the other motifs is unknown. This provides directions for future investigations of alternative activities of TPP II. The obtained signatures provide an efficient bioinformatic tool for the identification of TPP II homologues. Hence, a TPP II sequence homologue from fission yeast, Schizosaccharomyces pombe, was identified and demonstrated to encode the TPP II-like protein previously reported as multicorn. Furthermore, an homologous protein was found in the prokaryote Blastopirellula marina, albeit the TPP II function was apparently not conserved. This gene is probably the result of a rare gene transfer from eukaryote to prokaryote.
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