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Introduction: Poincianella bracteosa (Tul.) L.P. Queiroz. (Fabaceae), known as catingueira, is traditionally used in medicine to treat diarrhea, hepatitis and anemia. However, there are no studies on their toxicogenetic effects. Objective: The present study aimed to investigate the phytochemical profile as well as the mutagenic and antimutagenic potential of P. bracteosa aqueous bark extract in Allium cepa and Mus musculus. Methods: The extract from barks was diluted in distilled water to yield the four concentrations (2, 4, 8 and 16 mg/ml) used in the A. cepa bioassay and the three doses (10, 20 and 40 mg/Kg) administered to the mice (five animals per group). The phytochemical profile was performed by the colorimetric test to identify the main secondary metabolites in the bark extract. After treatment, five-thousand meristematic cells were analyzed to determine the mitotic index, the mean number of chromosome alterations and the percentage of damage reduction. For mice, after 24, 48 and 72 h, tail blood was collected from each animal for the preparation of two slides per animal. For each animal, 2 000 normochromatic erythrocytes per mice were evaluated to establish the number of micronuclei and the protective effect. Data were analyzed by Kruskal-Wallis test (P < 0.05). Results: The phytochemical analysis of the extract detected reducing sugars and tannins. None of the concentrations of extract was cytotoxic and the cytoprotective effect was observed in A. cepa for all treatments (pre-, simultaneous and post-). The total mean of chromosome alterations in all concentrations indicated a non-mutagenic activity of the bark. The percentage of damage reduction was observed in the pre- (77.6 to 90.5 %), simultaneous (95.6 to 114.7 %) and post- (84.8 to 117.7 %) treatments. In mice, none of the dosages of extract presented mutagenic effect and the percentage of damage reduction varied from -21.16 to 78.63 % (pre-); from 27.51 to 101.28 % (simultaneous) and from 85.47 to 120.63 % (post-treatment). Conclusions: Probably, the phytochemicals in the extract did not interfere with the cell cycle (A. cepa) nor caused damage to the DNA (A. cepa and mice), and exhibited protective effect in both studied species. The observed data indicate the importance of P. bracteosa bark extract for the inhibition of damage and chemoprevention. However, more studies should be carried out to ensure its protective effect on the genetic material. [ABSTRACT FROM AUTHOR]

Understanding the effects of heavy metals in aquatic ecosystems is of significant importance due to their potential to bioaccumulate at various trophic levels and induce damage in DNA. Mercury is considered one of the most dangerous heavy metals, causing chromosomal breakage (clastogenic event) or spindle dysfunction (aneugenic event), that can lead to the formation of encapsulated chromatin into a separate smaller nucleus, generally referred to as a micronucleus. We evaluated the sensitivity of the micronucleus test in the neotropical cichlid Andinoacara rivulatus (Günther 1860). The fish were divided into four groups of 16 individuals, and each group was placed in separate aquaria (140 L) provided with filtered water and constant aeration. Fish were exposed to mercury chloride (HgCl2) at doses 0.1, 0.25, and 0.50 mg/kg body weight, administered by intraperitoneal (IP) injection. Fish from the control group were injected with a physiologic solution. The following erythrocyte anomalies were identified: erythrocytes with micronuclei varying to some extent in size and position in the cytoplasm, blebbed nucleus, binucleated cell, nuclei showing a deep invagination toward the center (notched nuclei). Examination of blood smears demonstrated a higher level of micronucleus and notched erythrocytes in fish injected with HgCl2 than in the controls. There were significant differences in the frequency of micronucleated and notched erythrocytes among the groups exposed to mercury. Linear regression analysis revealed a positive relationship between the frequency of micronucleated and notched erythrocytes (P< 0.0001), with a moderately strong correlation coefficient (R= 0.737). We propose that, in addition to the two so far known mechanisms of micronucleus formation (spindle apparatus damage and chromosomal ruptures), chromatin fragmentation in notched nuclei resulting from a combination of the cytotoxic effects of mercury and mechanical stress, may be a third mechanism of micronuclei genesis. [ABSTRACT FROM AUTHOR]

La prueba de micronúcleos (MN) en sangre periférica es rápida, sencilla, económica y sirve para detectar genotóxicos ambientales. Los MN son fragmentos de cromosomas o cromosomas completos que por alguna causa quedan fuera del núcleo en mitosis, pero que incrementan significativamente cuando los organismos que los presentan de manera espontánea se exponen a genotóxicos. Por lo tanto, el requisito para que una especie pueda ser utilizada para esta prueba es que presente eritrocitos micronucleados espontáneos (EMNe), con lo que estas especies pueden ser potenciales bioindicadores de genotóxicos micronucleogénicos, con sólo una gota de su sangre. En el presente articulo es mostramos 9 especies de felinos que como característica general presentan EMNe. Del total de especies de felinos, el gato ha sido previamente probado, con resultados positivos y ya que también el león, yaguaroundi, lince, jaguar, puma, tigre de bengala, ocelote y leopardo presentan EMNe, esta familia puede ser propuesta como un grupo potencialmente adecuado para estudios de toxicogenética. En otras palabras, cada una de estas especies puede llegar a ser un modelo potencial para determinar exposición a genotóxicos en nuestro entorno, de una manera sencilla y rápida.Felines: an alternative in genetic toxicology studies? The micronuclei (MN) test carry out in peripheral blood is fast, simple, economic and it is used to detect genotoxic environmental agents. MN are fragments of chromosomes or complete chromosomes remaining in the cytoplasm after cell division, which increase when organisms are exposed to genotoxic agents. Therefore, species with the highest values of spontaneous micronucleated erythrocytes (MNE) are the most suitable to be potentials biomonitor of micronucleogenic agents, using a drop of blood. Nine species of Felines that present spontaneous MNE in peripheral blood are shown. From these species, the cat has been previously proven, with positive results and also lion (Panthera leo), yaguaroundi (Felis yagoaroundi), lynx (Lynx ruffus), jaguar (Panthera onca), puma (Puma concolor), tiger (Panthera tigris), ocelote (Felis padalis) and leopard (Panthera pardus) display spontaneous MNE, and with this characteristic this Family can be propose like a potential group to be used in toxicogenetic studies. Rev. Biol. Trop. 56 (2): 969-974. Epub 2008 June 30.

Con el objetivo de esclarecer la posible existencia de anomalías citogenéticas que aminoren la fertilidad del polen de Aloe vera, se analizó la etapa de proliferación celular que lleva a la formación de células madres del polen (CMPs). Se recolectaron botones florales (BF) en 25 plantas de una población ubicada a 10°34’15’’ N, 64°12’08’’ W, los cuales fueron fijados en Carnoy I por 24 h y almacenados en etanol (70 % v/v). Las observaciones se realizaron en preparaciones temporales obtenidas por la tinción del contenido de las anteras suspendidas en orceína acética (1.5 % p/v) por 5 minutos. De las 9 411 células analizadas, 17 % mostraron 1-8 puentes entre cromátidas hermanas, 13 % 1-7 micronúcleos de 0.9-4.8 µm, 8.1 % estaban unidas por puentes y 0.1 % no contenían cromatina. El resto de las células (61.8 %) presentó configuraciones aparentemente normales y sin variaciones morfométricas. La proliferación irregular de una fracción de CMPs (39.2 %) sugiere que las condiciones ambientales de la zona árida donde se realizaron los muestreos inducen inestabilidad cromosómica y cambios fisiológicos que afectan el normal desarrollo de la mitosis premeiótica, generando pérdida o adición de fragmentos, asociados a deficiencias y duplicaciones génicas.

Para determinar si la exposición laboral a plaguicidas produce daño al material genético se utilizó como biomarcador de efecto la presencia de micronúcleos en células del epitelio oral de trabajadoras de Guápiles y Siquirres, Costa Rica. También se analizaron otras anormalidades nucleares que pueden ser indicio de genotoxicidad o de citotoxicidad. El grupo de mujeres expuestas a plaguicidastrabajaban en plantas empacadoras de diferentes fincas bananeras independientes. El grupo de mujeres no expuestas nunca habían trabajado en labores agrícolas, no vivían dentro de una finca bananera, así como tampoco sus esposos o compañeros. Se obtuvo información acerca del estilo de vida, historia médica y familiar de las participantes mediante una entrevista. No se encontró un aumento significativo en la frecuencia de micronúcleos en el grupo de expuestas con respecto a las no expuestas. Las otras anormalidades nucleares mostraron indicios de citotoxicidad y genotoxicidad en el grupo de no expuestas, asociados a ingesta de café y a radiografías dentales. Estos resultados no descartan a los plaguicidas como agentes capaces de causar daño genético, sino que más bien los micronúcleos de la mucosa oral no parecen ser el biomarcador más adecuado para medirlo.Micronuclei and other nuclear abnormalities in the oral epithelium of female workers exposed to pesticides. In order to study if banana fields labour exposure to pesticides produces some kind of DNA damage, we determine the presence of micronuclei in epithelial oral cells in working women in Guapiles and Siquirres, Costa Rica, as an effect biomarker. We also analyzed other abnormalities in the nucleus of those cells such as broken-egg, karyolysis or kariorrhexis, to see if there was some kind of genotoxicity or citotoxicity. The women group exposed to pesticides worked in packing bananas plant from different independent farms. The control group of women had never done any farming tasks; they did not live in the banana fields, neither their husband. We got information about the life style, medical and familial history of the participants through an interview. We did not found any significant increment in the frequency of micronuclei form the exposed group compared with the controls. The other nuclei abnormalities showed signs of citotoxicity or genotoxicity in the controls, associated with the intake of coffee and dental x-rays. These results do not rule out at that pesticides used in packing bananas are agents capable of producing damage to the DNA, but it seems that micronuclei from the oral epithelium is not the most adequate marker to measure it. Rev. Biol. Trop. 52(3): 611-621. Epub 2004 Dic 15.

The micronuclei (MN) test carry out in peripheral blood is fast, simple, economic and it is used to detect genotoxic environmental agents. MN are fragments of chromosomes or complete chromosomes remaining in the cytoplasm after cell division, which increase when organisms are exposed to genotoxic agents. Therefore, species with the highest values of spontaneous micronucleated erythrocytes (MNE) are the most suitable to be potentials biomonitor of micronucleogenic agents, using a drop of blood. Nine species of Felines that present spontaneous MNE in peripheral blood are shown. From these species, the cat has been previously proven, with positive results and also lion (Panthera leo), yaguaroundi (Felis yagoaroundi), lynx (Lynx ruffus), jaguar (Panthera onca), puma (Puma concolor), tiger (Panthera tigris), ocelote (Felis padalis) and leopard (Panthera pardus) display spontaneous MNE, and with this characteristic this Family can be propose like a potential group to be used in toxicogenetic studies. [ABSTRACT FROM AUTHOR]

Karyological instability during pollen mother cells formation in Aloe vera (Aloaceae). In order to clarify possible cytogenetic anomalies that reduce pollen fertility, premeiotic mitosis was studied in Aloe vera plants from a naturalized population in the northeast of Venezuela (10°34'15'' N and 64°12'08'' W). Karyological configurations were evaluated during the stage of cell proliferation leading to the formation of pollen mother cells (PMCs). The sampling was carried out in March 2005, choosing inflorescences without mechanical or biological damage from 25 plants selected at random. Flower buds (FB) 2 to 6 mm in length were collected from 7:00 AM through 6:00 PM, their perianths removed, and fixed in Carnoy I (3:1 ethanol/glacial acetic acid) for 24 h and stored in ethanol (70 % v/v) until observation. Light microscope observations were done on temporary preparations obtained by overflowing anther content suspended in acetic orcein (1.5 % w/v) for 5 min and softly squashing with the cover slip. A total of 9 411 cells were analyzed. Upper mitotic activity was observed in FB from 3.8 ± 0.09 mm long, collected at 11:00 AM through 1:00 PM; 17% of PMCs showed one to eight sister chromatid bridges from anaphase to telophase; 13%, one to seven micronucleus of variable diameter (0.9 to 4.8 μm); 8.1% were united by thin chromatin filaments, and 0.1% lacked a nucleus. Other evaluated cells (61.8%) had apparently normal mitotic configurations, without considerable morphometric variations. The evident irregular proliferation of a PMCs fraction (39.2%) suggests that environmental stress conditions (day temperatures ranging 32.7 to 39.8°C, high solar radiation and low humidity) induce chromosome instability and physiologic changes that affect the normal development during premeiotic mitosis. As a consequence, loss or addition of chromosome fragments can occur in association with deficiencies and gene duplications. [ABSTRACT FROM AUTHOR]