3 research outputs found
Acetylcholinesterase inhibition and micronucleus frequency in oysters (Crassostrea corteziensis) exposed to chlorpyrifos
Chlorpyrifos (CPF) is an Organophosphorous pesticide (OP) that has been widely used for both agricultural and domestic pest control. To date, there is little information regarding the effects of this pesticide on aquatic organisms, particularly oysters. The aim of this study was to evaluate Acetylcholinesterase (AChE) activity and Micronucleus (MN) frequency in the oyster Crassostrea corteziensis in laboratory exposure with CPF (20, 40, 60, 80, and 160 µg/L) and in a field study. The results showed that AChE was reduced 60 - 82 % in oysters exposed to CPF, relative to the negative control. Similar AChE results were observed in oysters collected from the Boca de CamichĂn Estuary in Nayarit, Mexico; with respect to genetic damage, evaluated through MN, treatment with CPF did not induce the MN frequency, nor did the oyster from the field study exhibit an increase in this biomarker. These results suggest that C. corteziensis is a sensitive model for evaluating the acute toxicity of OP in laboratory studies as well in the field. In addition, it generates prospects on studying mechanisms through which the oyster could possess resistance to genotoxic agents, as well as its being a reliable model for evaluating the genotoxic effects of xenobiotics through the MN technique.El clorpirifos (CPF) es un pesticida organofosforoso (OP) que ha sido ampliamente utilizado tanto para el control de plagas agrĂcolas como domĂ©sticas. Hasta la fecha, hay poca informaciĂłn sobre los efectos de este pesticida en los organismos acuáticos, particularmente las ostras. El objetivo de este estudio fue evaluar la actividad de la acetilcolinesterasa (AChE) y la frecuencia del micronĂşcleo (MN) en la ostra Crassostrea corteziensis en exposiciĂłn de laboratorio con CPF (20, 40, 60, 80 y 160 ÎĽg / L) y en un estudio de campo. Los resultados mostraron que la AChE se redujo de 60 a 82% en ostras expuestas a CPF, en relaciĂłn con el control negativo. Se observaron resultados similares de AChE en las ostras recolectadas en el estuario de Boca de CamichĂn en Nayarit, MĂ©xico; Con respecto al daño genĂ©tico, evaluado a travĂ©s de MN, el tratamiento con CPF no indujo la frecuencia MN, ni la ostra del estudio de campo mostrĂł un aumento en este biomarcador. Estos resultados sugieren que C. corteziensis es un modelo sensible para evaluar la toxicidad aguda de OP en estudios de laboratorio, asĂ como en el campo. Además, genera perspectivas sobre el estudio de mecanismos a travĂ©s de los cuales la ostra podrĂa poseer resistencia a los agentes genotĂłxicos, asĂ como su ser un modelo fiable para evaluar los efectos genotĂłxicos de los xenobiĂłticos a travĂ©s de la tĂ©cnica MN
Haplotype structure in Ashkenazi Jewish BRCA1 and BRCA2 mutation carriers
Three founder mutations in BRCA1 and BRCA2 contribute to the risk of hereditary breast and ovarian cancer in Ashkenazi Jews (AJ). They are observed at increased frequency in the AJ compared to other BRCA mutations in Caucasian non-Jews (CNJ). Several authors have proposed that elevated allele frequencies in the surrounding genomic regions reflect adaptive or balancing selection. Such proposals predict long-range linkage disequilibrium (LD) resulting from a selective sweep, although genetic drift in a founder population may also act to create long-distance LD. To date, few studies have used the tools of statistical genomics to examine the likelihood of long-range LD at a deleterious locus in a population that faced a genetic bottleneck. We studied the genotypes of hundreds of women from a large international consortium of BRCA1 and BRCA2 mutation carriers and found that AJ women exhibited long-range haplotypes compared to CNJ women. More than 50% of the AJ chromosomes with the BRCA1 185delAG mutation share an identical 2.1 Mb haplotype and nearly 16% of AJ chromosomes carrying the BRCA2 6174delT mutation share a 1.4 Mb haplotype. Simulations based on the best inference of Ashkenazi population demography indicate that long-range haplotypes are expected in the context of a genome-wide survey. Our results are consistent with the hypothesis that a local bottleneck effect from population size constriction events could by chance have resulted in the large haplotype blocks observed at high frequency in the BRCA1 and BRCA2 regions of Ashkenazi Jew