Daño en el ADN de linfocitos humanos por efecto de cloroquina / Damage to human lymphocyte DNA from chloroquine effect

RESUMEN El objetivo del estudio fue evaluar el efecto de cloroquina (CQ) en linfocitos humanos a través del ensayo cometa. Los linfocitos fueron aislados de muestras de sangre periférica obtenidas de tres donantes sanos, no fumadores de 24 a 30 años. Los linfocitos aislados fueron expuestos durante una hora a diversos tratamientos: peróxido de hidrógeno 2,5 % (control positivo), buffer fosfato salino 1X (control negativo) y cloroquina a concentraciones de 0 µg/ml, 0,25 µg/ml; 5 µg/ml y 300 µg/ml. Se registró los promedios del porcentaje de ADN en la cola del cometa, momento de la cola y momento de la cola de Olive, encontrándose diferencias significativas entre las diversas concentraciones de CQ (p<0,01). Asimismo, la magnitud de daño del ADN se incrementó en función de la concentración de CQ. Se demostró el efecto genotóxico de CQ en linfocitos humanos expuestos in vitro.

ABSTRACT The objective of the study was to evaluate the effect of chloroquine (CQ) on human lymphocytes through the Comet Assay. Lymphocytes were isolated from peripheral blood samples obtained from three healthy, non-smoking donors aged 24 to 30 years. The isolated lymphocytes were exposed for one hour to various treatments: hydrogen peroxide 2.5% (positive control), saline buffer phosphate 1X (negative control) and chloroquine at concentrations of 0 µg/ml, 0.25 µg/ml; 5 µg/ml and 300 µg/ml. The averages of the percentage of DNA in the comet tail, moment of tail and moment of Olive's tail were recorded, with significant differences between the different concentrations of CQ (p<0.01). Also, the magnitude of DNA damage was increased as a function of the CQ concentration. The genotoxic effect of CQ was demonstrated in human lymphocytes exposed in vitro.

Diferenciación genética de tilapia roja y gris (Oreochromis niloticus) mediante microsatélites y marcadores SCAR como indicadores del sexo genético

El objetivo del trabajo fue realizar la estandarización de los protocolos moleculares, diferenciar los linajes de la tilapia roja y gris mediante microsatélites de ADN y evaluar los marcadores SCAR5F-X/5R y SCAR-5F/5R-Y como indicadores del sexo genético de O. niloticus. El microsatélite UNH106 permitió diferenciar genéticamente los linajes de la tilapia roja de la gris. Los microsatélites UNH136, UNH115 y UNH995 presentaron loci monomórficos tanto en la tilapia roja como en la gris en el lote poblacional del Centro Experimental de Genética de la Universidad Nacional de Trujillo. Se describen los tamaños de fragmentos para los microsatélites y del gen de referencia β actin. También se confirmó la efectividad de los marcadores SCAR como informativos en la determinación del sexo genético evaluados en hembras XX y YY y machos XY y YY de O. niloticus roja y hembras XX y machos XY de O. niloticus gris.

The aims of this work was to develop a standardized molecular protocols, to differentiate red and gray tilapia lineages using DNA microsatellites and to evaluate SCAR-5F-X/5R and SCAR-5F/5RY markers associated with the phenotypic sex of O. niloticus. The UNH106 microsatellite allowed differentiating genetically the lineages of red tilapia from gray. The markers UNH136, UNH115 and UNH995 presented monomorphic loci in both the red and gray tilapia in the population stock of the Centro Experimental de Genética of the Universidad Nacional de Trujillo. Fragment sizes for microsatellites and the reference gene β actin are described. The effectiveness of SCAR markers as informative in the determination of the genetic sex in XX and YY females and XY y YY males of red tilapia and XX females and XY males of gray tilapia was also confirmed.

Model of chromosome associations in Mus domesticus spermatocytes

Understanding the spatial organization of the chromosomes in meiotic nuclei is crucial to our knowledge of the genome's functional regulation, stability and evolution. This study examined the nuclear architecture of Mus domesticus 2n=40 pachytene spermatocytes, analyzing the associations among autosomal bivalents via their Centromere Telomere Complexes (CTC). The study developed a nuclear model in which each CTC was represented as a 3D computer object. The probability of a given combination of associations among CTC was estimated by simulating a random distribution of 19 indistinguishable CTC over n indistinguishable "cells" on the nuclear envelope. The estimated association frequencies resulting from this numerical approach were similar to those obtained by quantifying actual associations in pachytene spermatocyte spreads. The nuclear localization and associations of CTC through the meiotic prophase in well-preserved nuclei were also analyzed. We concluded that throughout the meiotic prophase: 1) the CTC of autosomal bivalents are not randomly distributed in the nuclear space; 2) the CTC associate amongst themselves, probably at random, over a small surface of the nuclear envelope, at the beginning of the meiotic prophase; 3) the initial aggregation of centromere regions occurring in lepto-zygotene likely resolves into several smaller aggregates according to patterns of preferential partitioning; 4) these smaller aggregates spread over the inner face of the nuclear envelope, remaining stable until advanced stages of the meiotic prophase or even until the first meiotic division.

Efecto genotóxico del dicromato de potasio en eritrocitos de sangre periférica de Oreochromis niloticus (TILAPIA) / Genoto xic efect of potassium dicromate in peripheral blod eryt hrocytes of Oreochromis niloticus (TILAPIA)

Existen múltiples reportes del efecto genotóxico y cancerígeno del cromo VI, los seres humanos tenemos una permanente exposición a este elemento. Objetivos. Evidencias la genotoxicidad del dicromato de potasio utilizando como sistema biológico a Oreochromis niloticus "tilapia", mediante el test de micronúcleos y la cuantificación de nuclear buds, en eritrocitos de sangre periférica. Materiales y métodos. Los individuos fueron expuestos a concentraciones crecientes (0,0, 0,2, 0,4 y 0,8 ppm) de dicromato de potasio. Se obtuvieron muestras de sangre periférica, del arco branquial de cada individuo (cuatro por grupo), a los tres y siete días de tratamiento, las cuales fueron procesadas y coloreadas con Giemsa 5% y se cuantificaron eritrocitos con micronúcleos y nuclear buds en sangre periférica. Resultados. Se encontró un incremento significativo de las frecuencias de micronúcleos y nuclear buds directamente proporcional a la concentración del dicromato de potasio en los individuos expuestos (p < 0,05). Conclusiones. El dicromato de potasio produce daño genético en los eritrocitos de O. niloticus.

Due multiple reports of the genotoxic and carcinogenic effect of chromium VI and the permanent exposure of the human beings to this element. Objective. Contributing new evidence of the genotoxicity of potassium dichromate using the biological system Oreochromis niloticus "tilapia" through the micronucleus test and the nuclear quantification of buds in erythrocytes of peripheral blood. Material and methods. The individuals were exposed to increasing concentrations (0.0, 0.2, 0.4 and 0.8 ppm) of potassium dichromate. Peripheral blood samples of the branchial arc of each individual were taken at 3th and 7th day of treatment which were processed and colored with Giemsa 5%, erythrocytes in peripheral blood with micronuclei and nuclear buds were quantified. Results. A significant increase of frequencies of micronucleus and nuclear buds in the exposed individuals were registered which were directly proportional to the potassium dichromate concentration (p < 0.05). Conclusions. Potassium dichromate caused genetic damage in the cells of O. niloticus.