Primera cita de Cloudina carinata Cortijo et al., 2010 en Sudamérica, Formación de Tamengo, Grupo de Corumbá, Brasil Brazil

It is herein presented the unprecedented occurrence of Cloudina carinata Cortijo et al., 2010 in the American continent. This new occurrence expanded the geographic distribution of this species, until now reported from sections in Spain and Siberia. The assembled biomineralizing metazoans Cloudina carinata, Cloudina lucianoi (Beurlen & Sommer, 1957) and Corumbella werneri Hahn et al., 1982 are presented for the first time from the Tamengo Formation, Corumbá Group, Porto Figueiras section, Corumbá Municipality, Mato Grosso do Sul State, Brazil. This new occurrence could be employed as an additional biostratigraphic tool for international correlation of the terminal Ediacaran, as well as for palaeobiogeographic and palaeoecologic reconstructions.Se documenta en este resumen la primera aparición de Cloudina carinata Cortijo et al., 2010 en el continente americano. Esta nueva aparición extiende la distribución geográfica de esta especie, hasta ahora restringida a España y Siberia. Se presenta por primera vez en la Formación de Tamengo (Corumbá, Estado de Mato Grosso do Sul, Brasil) la asociación de metazoos mineralizados compuesta por Cloudina carinata, Cloudina lucianoi (Beurlen & Sommer, 1957) y Corumbella werneri Hahn et al., 1982. Esta asociación podría ser útil como marcador bioestratigráfico en las correlaciones internacionales del Ediacárico terminal, así como para futuras reconstrucciones paleobiogeográficas y paleoecológicas

Análisis paleontológicos a través límite Ediacárico-Cámbrico, Grupo Alto Corumbá, Brasil

This work presents the results of a palaeontological analysis focused on twenty-six species sampled in five sections of the Tamengo and Guaicurus formations, Corumbá and Ladário regions: Corcal and Laginha quarries, Porto Sobramil, Porto Figueiras and Ecoparque Cacimba. Besides, palaeoecological and palaeoenvironmental inferences are presented based on the occurrence of this fossil assemblage. Cloudina carinata Cortijo et al., 2010, previously documented in Spain and Siberia, presents an unprecedented occurrence in the American continent, in siltstones of the Tamengo Formation at Porto Figueiras section, Municipality of Corumbá, Mato Grosso do Sul State, Brazil. The biota of the Tamengo Formation is updated and composed of three biomineralizing metazoans, including poriferan spicules, putative sponge gemmule, and a sessile epibiontic prokaryotic colony. The present work also deals with the taxonomy and stratigraphic distribution of four ichnospecies and three vendotaenid species that integrate the updated benthic fauna for the upper portion of Corumbá Group. The species diversity of the Tamengo Formation was complemented by the occurrence of sixteen microfossil species that possibly represent a marine planktic assemblage. A dramatic change was identified in the palaeoenvironmental conditions of the Tamengo to Guaicurus formations, followed by a mass extinction event, possibly linked to the global Ediacaran- Cambrian mass extinction. In addition, organic-walled microfossils were prepared and analyzed from sections of three countries: nine species from the Nomtsas Formation, Namibia; four species from the Tagatiya Guazu Formation, Paraguay; and six species from the Dengying Formation, China. An international biostratigraphic essay consisting of six biozones is proposed for the uppermost Ediacaran and one biozone for the earliest Cambrian.Se presenta en este trabajo el análisis paleontológico de 26 especies fósiles muestradas en cinco cortes de las Formaciones de Tamengo y Guaicurus en las regines de Corumbá y Ladário: canteras de Corcal y Laginha, Porto Sobramil, Porto Figueiras y Ecoparque Cacimba. Además, se añaden varias interpretaciones paleoecológicas y ambientales, basadas en el registro fósil. Cloudina carinata Cortijo et al., 2010, previamente citada en España y Siberia, aparece por primera vez en el continente Americano, concretamente en limolitas de la Formación Tamengo en el corte de Porto Figueiras, Corumbá, Estado de Mato Grosso do Sul, Brasil. La biota de la Formación Tamengo incluye tres metazoos mineralizados, que incluyen espículas de poríferos, posibles gémulas de esponjas y una colonia sésil de procaiotas epibentónicos. Este trabajo se centra en la taxonomía y distribución estratigráfica de cuatro icnoespecies y tres especies de vendoténidos que forman la fauna bentónica de la parte superior del Grupo de Corumbá. La biodiversidad de la Formación Tamengo ha sido completada con el registro de 16 especies microfósiles que representan posiblemente una asociación plantónica marina. Se ha identificado un cambio drástico en las condiciones ambientales de las Formaciones Tamengo y Guaicurus, que culminan en un evento de extincinón masiva posiblemente relacionado con la extincición en masa que marca el tránsito global Ediácarico- Cámbrico. Por otro lado, se han extraído microfósiles de pared orgánica de varios afloramientos: nueve especies de la Formación de Nomtsas (Namibia), cuatro de la Formación Tagatiya Guazu (Paraguay) y seis de la Formación Dengying (China). Se propone un marco bioestratigráfico para el Ediacárico terminal que incluye seis biozonas y una biozona para el Cámbrico basal

Double aortic arch with double aneuploidy—rare anomaly in combined Down and Klinefelter syndrome

A 14-month-old boy with double aneuploidy and a double aortic arch suffered from frequently recurrent severe feeding and respiratory problems. Chromosomal analysis showed a 48,XXY + 21 karyotype: a double aneuploidy of Down syndrome (DS) and Klinefelter syndrome (KS). Only four cases of double aneuploidy (DS + KS) associated with congenital heart defects have been published of which none had a double aortic arch. Our case report should draw attention to the possibility of a double aortic arch in patients with severe feeding and respiratory problems and a double aneuploidy

Avaliação da instabilidade genômica e prevenção de câncer

OBJECTIVES: This study aimed at verifying the damage index acquired from the environment and from an inherited condition in the leukocytes of workers occupationally exposed to Xradiation and antineoplastic drugs, patients with Down syndrome, Fanconi anemia, and controls. MATERIAL AND METHODS: Cytokinesis-block micronucleus assay (CB-MN) and single-cell-gel electrophoresis (SCGE) were employed in 22 workers potentially exposed to X-radiation and 22 controls matched for age, sex, and smoking habits from a hospital in southern Brazil. The same evaluation was employed in 12 individuals who had been occupationally exposed to antineoplastic drugs and in 14 patients with Fanconi anemia (FA), 30 with Down syndrome (DS), and 30 controls,in order to examine the sensitivity of the techniques to detect specific genome instability. RESULTS: Both CB-MN and SCGE showed increased genetic damage in the cells of exposed individuals. In individuals handling antineoplastic drugs, no statistically difference was found when using CB-MN; however, the mean value of SCGE was significantly higher in exposed individuals when compared to controls. Down syndrome presented an increase just in the SCGE technique; the frequency of micronuclei and dicentric bridges was similar to that found in controls. Both CB-MN and SCGE showed increased genetic damage in the cells of individuals with Fanconi anemia. The high frequency of micronuclei seems to be due to clastogenic events, since the frequency of dicentric bridges was also elevated. DISCUSSION: Both methods are efficient for monitoring mutagenic events in exposed populations or individuals presenting genetic instability. CB-MN represents a longer time of exposure, while SCGE detects momentary DNA damage and/or repair activity. The combination of both techniques is recommended to monitor chronically exposed populations. Changes in lifestyle may constitute an important way of preventing carcinogenesis, either in individuals presenting increased risk and in the general population.OBJETIVOS: Este estudo teve como objetivo avaliar o nível de mutagênese em indivíduos normais não expostos, em trabalhadores expostos à radiação ionizante e drogas antineoplásicas e em indivíduos portadores de doenças genéticas, comparando os níveis de mutagênese herdada com aqueles adquiridos por exposição a mutágenos. MÉTODOS: A técnica de micronúcleo em linfócitos do sangue periférico e a técnica do cometa ou eletroforese em célula única foram empregados em 22 trabalhadores potencialmente expostos à radiação X, 12 potencialmente expostos a drogas antineoplásicas, 34 controles adultos, 14 pacientes com anemia de Fanconi (AF), 30 com síndrome de Down (SD) e 30 controles infantis, do Hospital de Clínicas de Porto Alegre. RESULTADOS: As duas técnicas mostraram um aumento no dano genético em células de indivíduos expostos a radiação-X. Nos indivíduos que manuseiam drogas antineoplásicas, não foi encontrada diferença significativa com a técnica de micronúcleo; no entanto, o índice de dano avaliado pela técnica do cometa foi significativamente maior em indivíduos expostos em relação a controles. Pacientes com síndrome de Down apresentaram um aumento no índice medido pela técnica do cometa; a freqüência de micronúcleos e pontes dicêntricas foi semelhante ao valor encontrado em controles. Tanto a técnica de micronúcleo como a técnica do cometa mostraram aumento de dano genético nas células de indivíduos com anemia Fanconi. A alta freqüência de micronúcleos parece ser devida a eventos clastogênicos, uma vez que a freqüência de pontes dicêntricas também se encontrava elevada. DISCUSSÃO: As duas técnicas são eficientes na monitoração de eventos mutagênicos em populações expostas ou em indivíduos que apresentam instabilidade genética. A técnica de micronúcleo representa um tempo maior de exposição, enquanto que a técnica do cometa detecta dano momentâneo ao DNA e/ou atividade de reparo. A combinação das duas técnicas é recomendada para monitorar populações cronicamente expostas. Mudanças no estilo de vida podem constituir uma forma importante de prevenir carcinogênese, tanto em indivíduos que apresentam risco aumentado como na população em geral

The role of GRK6 in animal models of Parkinson's Disease and L-DOPA treatment

G protein-coupled Receptor Kinase 6 (GRK6) belongs to a family of kinases that phosphorylate GPCRs. GRK6 levels were found to be altered in Parkinson's Disease (PD) and D2 dopamine receptors are supersensitive in mice lacking GRK6 (GRK6-KO mice). To understand how GRK6 modulates the behavioral manifestations of dopamine deficiency and responses to L-DOPA, we used three approaches to model PD in GRK6-KO mice: 1) the cataleptic response to haloperidol; 2) introducing GRK6 mutation to an acute model of absolute dopamine deficiency, DDD mice; 3) hemiparkinsonian 6-OHDA model. Furthermore, dopamine-related striatal signaling was analyzed by assessing the phosphorylation of AKT/GSK3β and ERK1/2. GRK6 deficiency reduced cataleptic behavior, potentiated the acute effect of L-DOPA in DDD mice, reduced rotational behavior in hemi-parkinsonian mice, and reduced abnormal involuntary movements induced by chronic L-DOPA. These data indicate that approaches to regulate GRK6 activity could be useful in modulating both therapeutic and side-effects of L-DOPA

Genotoxicity of Nicotiana tabacum leaves on Helix aspersa

Tobacco farmers are routinely exposed to complex mixtures of inorganic and organic chemicals present in tobacco leaves. In this study, we examined the genotoxicity of tobacco leaves in the snail Helix aspersa as a measure of the risk to human health. DNA damage was evaluated using the micronucleus test and the Comet assay and the concentration of cytochrome P450 enzymes was estimated. Two groups of snails were studied: one fed on tobacco leaves and one fed on lettuce (Lactuca sativa L) leaves (control group). All of the snails received leaves (tobacco and lettuce leaves were the only food provided) and water ad libitum. Hemolymph cells were collected after 0, 24, 48 and 72 h. The Comet assay and micronucleus test showed that exposure to tobacco leaves for different periods of time caused significant DNA damage. Inhibition of cytochrome P450 enzymes occurred only in the tobacco group. Chemical analysis indicated the presence of the alkaloid nicotine, coumarins, saponins, flavonoids and various metals. These results show that tobacco leaves are genotoxic in H. aspersa and inhibit cytochrome P450 activity, probably through the action of the complex chemical mixture present in the plant