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Determinacion in vitro de la susceptibilidad a la nitazoxanida de cuatro aislados de giardia duodenalis obtenidos de diferentes huespedes.


En México la giardiosis es la protozoosis intestinal más frecuente en los niños, para el tratamiento se utilizan los nitrofuranos, nitroimidazoles y benzimidazoles. Recientemente se introdujo un antiparasitario polivalente: la nitazoxanida (Ntz); del cual hay pocos estudios sobre su actividad antigiardiásica.

In Mexico giardiosis is the most prevalent parasitic disease in children. Treatment with antiparasitics derived from: nitroimidazoles, benzimidazoles and nitrofuranes have been used; but, some of them have undesirable side effects. Recently nitazoxanide (Ntz) was introduced in Mexico; however, there are few studies on Giardia duodenalis susceptibility to Ntz.


MEDICINA Y CIENCIAS DE LA SALUD Antiprotozoarios - Farmacología Parásitos intestinales - Veterinaria Giardia - Parasitología Tiazoles - Farmacología Antiprotozoal agents - Pharmacology Intestinal diseases, parasitic - Parasitology Intestinal diseases, parasitic - Veterinary Thiazoles - Pharmacology

Identification of the NADP+ structural binding site and coenzyme effect on the fused G6PD::6PGL protein from Giardia lamblia

Roberto Arreguin Yudibeth Sixto-López NOEMI CARDENAS-RODRIGUEZ Rosa Angélica Castillo-Rodríguez Daniel Ortega-Cuellar (2020)

Giardia lambia is a flagellated protozoan parasite that lives in the small intestine and is the causal agent of giardiasis. It has been reported that G. lamblia exhibits glucose-6-phosphate dehydrogenase (G6PD), the first enzyme in the pentose phosphate pathway (PPP). Our group work demonstrated that the g6pd and 6pgl genes are present in the open frame that gives rise to the fused G6PD::6PGL protein; where the G6PD region is similar to the 3D structure of G6PD in Homo sapiens. The objective of the present work was to show the presence of the structural NADP(+) binding site on the fused G6PD::6PGL protein and evaluate the effect of the NADP(+) molecule on protein stability using biochemical and computational analysis. A protective effect was observed on the thermal inactivation, thermal stability, and trypsin digestions assays when the protein was incubated with NADP(+). By molecular docking, we determined the possible structural-NADP(+) binding site, which is located between the Rossmann fold of G6PD and 6PGL. Finally, molecular dynamic (MD) simulation was used to test the stability of this complex; it was determined that the presence of both NADP(+) structural and cofactor increased the stability of the enzyme, which is in agreement with our experimental results.


BIOLOGÍA Y QUÍMICA NADP + structural binding site Stability 6GPD Docking Giardia lamblia

Final Opportunity to Rehabilitate an Urban River as a Water Source for Mexico City.

Marisa Mazari Hiriart Gustavo Perez Ortiz Ma. Teresa Orta Ledesma Felipe de Jesus Armas Vargas Marco Tapia Rosa Solano Ortiz Miguel Silva Isaura Yañez Noguez Yolanda Lopez Vidal Carlos Diaz Avalos (2014)

The aim of this study was to evaluate the amount and quality of water in the Magdalena-Eslava river system and to propose alternatives for sustainable water use. The system is the last urban river in the vicinity of Mexico City that supplies surface water to the urban area. Historical flow data were analyzed (1973-2010), along with the physicochemical and bacteriological attributes, documenting the evolution of these variables over the course of five years (2008-2012) in both dry and rainy seasons. The analyses show that the flow regime has been significantly altered. The physicochemical variables show significant differences between the natural area, where the river originates, and the urban area, where the river receives untreated wastewater. Nutrient and conductivity concentrations in the river were equivalent to domestic wastewater. Fecal pollution indicators and various pathogens were present in elevated densities, demonstrating a threat to the population living near the river. Estimates of the value of the water lost as a result of mixing clean and contaminated water are presented. This urban river should be rehabilitated as a sustainability practice, and if possible, these efforts should be replicated in other areas. Because of the public health issues and in view of the population exposure where the river flows through the city, the river should be improved aesthetically and should be treated to allow its ecosystem services to recover. This river represents an iconic case for Mexico City because it connects the natural and urban areas in a socio-ecological system that can potentially provide clean water for human consumption. Contaminated water could be treated and reused for irrigation in one of the green areas of the city. Wastewater treatment plants and the operation of the existing purification plants are urgent priorities that could lead to better, more sustainable water use practices in Mexico City.


Parasitología Giardia lamblia Contaminación de agua BIOLOGÍA Y QUÍMICA

Goblet cells: Are they an unspecific barrier against Giardia intestinalis or a gate?


La Giardiosis es una de las principales enfermedades parasitarias intestinales de los seres humanos, así como animales salvajes y domesticados. Se han descrito varios mecanismos protectores contra la infección. Sin embargo, la información específica sobre la relación entre giardiosis y el aumento de la proliferación de células caliciformes (GC) en pacientes infectados con Giardia intestinal (Syn G. duodenalis, G. lamblia) es escasa. En este trabajo comparamos y cuantificamos el número de GC y hemos inferido su estado metabólico en el intestino delgado de perros parasitados con Giardia intestinalis en comparación con perros sin parásitos. Los segmentos del intestino delgado se procesaron utilizando métodos rutinarios para la histología y la microscopía electrónica; Áreas y células fueron examinados con un Axiovision Ver. 4,0 sistema. Los datos se analizaron mediante ANOVA y la comparación de promedios. Los perros parasitados mostraron mayores números de GC que los no parasitados. Los promedios fueron: 20 +/- 0,81 GC / 25 microm (2) con gránulos de mucina independientes y 11 +/- 1,53 GC / 25 microm (2) que expulsaban moco, en comparación con 11 +/- 0,94 GC / 25 microm (2 ) Y 1 +/- 0,27 GC / 25 microm (2), respectivamente, en perros no parasitados (Tukey, p <0,001). Los aumentos en el número de GC parecen ser un mecanismo defensivo inespecífico contra los trofozoítos de Giardia. Sin embargo, hemos encontrado algunas pruebas de que la hiperplasia GC podría ser un perjudicial para la barrera epitelial que da lugar a puertas que permitan Giardia-invasión de tejidos.

Giardiosis is one of the major intestinal parasitic diseases of human beings as well as wild and domesticated animals. Several protective mechanisms against infection have been described. However, specific information about relationship between giardiosis and the increased proliferation of goblet cells (GC) in patients infected with Giardia intestinalis (Syn. G. duodenalis, G. lamblia) is scarce. In this work, we compare and quantify the number of GC, and have inferred their metabolic state in the small intestine of dogs parasitized with Giardia intestinalis compared to dogs without parasites. Small intestine segments were processed using routine methods for histology and electron microscopy; areas and cells were screened with an Axiovision Ver. 4.0 system. Data were analyzed by ANOVA and comparison of averages. Parasitized dogs showed higher GC numbers than nonparasitized ones. Averages were: 20 ± 0.81 GC/25 μm2 with independent mucin granules and 11 ± 1.53 GC/25 μm2 that were expelling mucus, compared to 11 ± 0.94 GC/25 μm2 and 1 ± 0.27 GC/25 μm2, respectively, in nonparasitized dogs (Tukey, p∈<∈0.001). The increases in GC number seem to be an unspecific defensive mechanism against Giardia trophozoites. However, we found some evidence supporting that GC hyperplasia could be a prejudicial to epithelial barrier that gives rise to gates allowing for Giardia-tissue invasion. © 2007 Springer-Verlag.


MEDICINA Y CIENCIAS DE LA SALUD Giardia lamblia - Patogenicidad Giardiasis - Prevencion y control Giardiasis - Transmisión Células caliciformes - Parasitología Intestino delgado - Parasitología Giardia lamblia - Pathogenicity Giardiasis - Prevention & control Giardiasis - Transmission Goblet cells - Parasitology Intestine, small - Parasitology Giardia intestinalis Giardiasis células de cáliz Mucinas Histopatología Invasión de tejido de giardia Giardia intestinalis Giardiasis goblet cells Mucins Histopathology Giardia -Tissue invasion

Disulfide Bridges in the Mesophilic Triosephosphate Isomerase from Giardia lamblia Are Related to Oligomerization and Activity


Triosephosphate isomerase from the mesophile Giardia lamblia (GlTIM) is the only known TIM with natural disulfide bridges. We previously found that oxidized and reduced thiol states of GlTIM are involved in the interconversion between native dimers and higher oligomeric species, and in the regulation of enzymatic activity. Here, we found that trophozoites and cysts have different oligomeric species of GlTIM and complexes of GlTIM with other proteins. Our data indicate that the internal milieu of G. lamblia is favorable for the formation of disulfide bonds. Enzyme mutants of the three most solvent exposed Cys of GlTIM (C202A, C222A, and C228A) were prepared to ascertain their contribution to oligomerization and activity. The data show that the establishment of a disulfide bridge between two C202 of two dimeric GlTIMs accounts for multimerization. In addition, we found that the establishment of an intramonomeric disulfide bond between C222 and C228 abolishes catalysis. Multimerization and inactivation are both reversed by reducing conditions. The 3D structure of the C202A GlTIM was solved at 2.1 Å resolution, showing that the environment of the C202 is prone to hydrophobic interactions. Molecular dynamics of an in silico model of GlTIM when the intramonomeric disulfide bond is formed, showed that S216 is displaced 4.6 Å from its original position, causing loss of hydrogen bonds with residues of the active-site loop. This suggests that this change perturb the conformational state that aligns the catalytic center with the substrate, inducing enzyme inactivation. © 2006 Elsevier Ltd. All rights reserved.


MEDICINA Y CIENCIAS DE LA SALUD Dimerización Disulfuros - Metabolismo Giardia lamblia - Efectos de drogas Giardia lamblia - Enzimología Proteínas mutantes - Química Proteínas mutantes - Metabolismo Oocistos -Citología Oocistos - Efectos de drogas Oocistos - Enzimología Estructura cuaternaria de proteína - Efectos de drogas Estructura secundaria de proteína - Efectos de drogas Estructura secundaria de proteína - Química Estructura secundaria de proteína - Metabolismo Triosa-Fosfato isomerasa - Química Triosa-Fosfato isomerasa -Metabolismo Trofozoítos - Citología Trofozoítos - Efectos de drogas Trofozoítos -Enzimología Dimerization Disulfides - Metabolism Giardia lamblia - Drug effects Giardia lamblia - Enzymology Mutant proteins - Chemistry Mutant proteins - Metabolism Oocysts - Cytology Oocysts - Drug effects Oocysts - Enzymology Protein structure, quaternary - Drug effects Protein structure, secondary - Drug effects Protein subunits-Chemistry metabolism Protein transport - Drug effects chemistry Triose-Phosphate isomerase - Metabolism Trophozoites - Cytology Trophozoites- Drug effects Trophozoites- Enzymology Triosephosphate Disulfide bonds Glycolysis Dinamic molecular