Genotoxic Biomonitoring in Children Living near the El Fraile Mine Tailings in Northern Guerrero State, Mexico.

A genotoxic study was conducted with 101 elementary school children (56 girls and 45 boys) in the 6-7, 8-9, and 10-12 age ranges from El Fraile rural community, which is located beside the El Fraile mine tailings in Taxco of Alarcon City, in northern Guerrero State, Mexico. For this, we used the alkaline comet assay in exfoliated buccal mucosa cells, scoring three genotoxic parameters: tail intensity, tail moment, and tail length. Additionally, we detected oxidative DNA damage through urinary 8-OHdG levels by enzyme-linked immunosorbent assay. We also evaluated a control group consisting of 101 children in the same age ranges from Chilpancingo City, Guerrero, who had never lived near mining zones. Genotoxic results showed that there was a significant increase in three genotoxic parameters and urinary 8-OHdG levels in the exposed children group compared with the control group. Analysis of MANOVA revealed that boys aged 8 and 9 years had higher DNA damage than girls from the same exposure group, and Spearman's analysis identified a positive correlation between DNA damage and sex and age. This study provides the first valuable genotoxic data in children living in areas with environmental pollution.

Bactericidal effect of silver nanoparticles against propagation of Clavibacter michiganensis infection in Lycopersicon esculentum Mill.

This study explored the use of silver nanoparticle as a bactericidal against the propagation of Clavibacter michiganensis onto tomatoes (Lycopersicon esculentum Mill). In Mexico, tomato production covers about 73% of the total vegetable production but it is affected by outbreak of bacteria canker caused by Clavibacter michiganensis subspecies michiganensis (Cmm). Silver ions possess inhibitor properties, bactericides and high specter antimicrobials. In this study, 6 groups of culture were prepared using 6 different petri dishes where silver nanoparticles of varying concentrations (120, 84, 48, 24, 12 and 0 µg) were added. Furthermore, each group was observed for 20 min, 1, 2, 12 and 24 h. The optimum concentration is 84 µg, which shows an average of 2 Cmm colonies after 20 min. Further increase to 120 µg shows no significant change. However, the average colonies was observed for 48 µg after 1, 2, 12, and 24 h. The obtained results indicate that silver nanoparticles are a promising inhibitor, bactericide and high a specter antimicrobial for treatment or prevention of Cmm.

Stress in callus of hippocratea excelsa: catalase activity, hydrogen peroxide content and canophyllol accumulation

En las células vegetales algunos factores adversos inducen frecuentemente estrés oxidativo, el cual genera síntesis de moléculas que activan una gama de señales en las rutas de transducción y antioxidantes. Una molécula-señal producida bajo estrés es el H2O2, el cual ha sido asociado a la producción de metabolitos secundarios in vitro y a la actividad antioxidante de las células vegetales. En este trabajo se utilizó la producción de canofilol en callos de Hippocratea excelsa como un ejemplo para demostrar el incremento en la producción de metabolitos secundarios bajo estrés. Semillas obtenidas de frutos fueron cultivadas in vitro para la obtención del callo. Dos diferentes tipos de estrés fueron aplicados: nutricional, reduciendo la cantidad de N2 en el medio, y osmótico, usando polietilenglicol. Se midió el contenido de canofilol y de H2O2, así como la actividad de la enzima catalasa. El estrés nutricional causó una respuesta diferente a la del estrés osmótico en la acumulación de canofilol y en la actividad de la catalasa, mientras que el contenido de H2O2 aumentó bajo ambos tipos de estrés. La mayor cantidad de canofilol (8 veces el control) se obtuvo bajo estrés nutricional en el tratamiento de 25 por ciento de N2. Este trabajo muestra que las respuestas en la producción de canofilol y la actividad de catalasa en callos de H. excelsa son señalizadas diferencialmente en los dos diferentes tipos de estrés aplicados.