Single cell gel electrophoresis as a tool to assess genetic damage in Heleobia cf. australis (Mollusca: Gastropoda) as sentinel for industrial and domestic pollution in Montevideo bay (Uruguay)

O conhecimento dos danos no DNA em organismos aquáticos de áreas poluídas é uma questão importante, já que a contaminação pode vir a alterar os organismos em níveis subletais. Apesar dos moluscos terem sido amplamente utilizados para monitorar a poluição da água, não há registros de estudos in vivo de genotoxicidade. Heleobia cf. australis é um pequeno gastrópode amplamente distribuído em quase todos os ecossistemas costeiros uruguaios, inclusive em locais altamente poluídos. O ensaio do cometa é um biomarcador genético do dano baseado na migração de fragmentos de DNA com carga negativa produzidas por agentes mutagênicos. Foram coletados indivíduos vivos na Baía de Montevidéu (área impactada) e Laguna Garzón (área controle) para analisar a presença de agentes mutagênicos que ocasionassem dano genético. Células de organismos da área impactada apresentaram níveis significativamente mais elevados de danos genéticos do que os obtidos na área controle. Esse nível de dano foi medido pela porcentagem de DNA na cauda. Embora preliminar, esta abordagem apoia a noção de que H. cf. australispoderia ser usado como sentinela para avaliar a presença de agentes mutagênicos em ambientes estuarinos, alertando sobre o impacto da poluição em estágios iniciais.The knowledge of the extent of DNA damage in aquatic organisms in polluted areas is an important issue because contamination may alter their health at sublethal levels. Although molluscs have been widely used to monitor water pollution, there are no records of in vivo genotoxicity studies. Heleobia cf. australis, is distributed in almost all Uruguayan coastal ecosystems, including highly polluted sites. The comet assay is a damage genetic biomarker based on the migration of negatively charged DNA fragments produced by mutagenic agents in individual cells. Live individuals were collected in the Montevideo Bay (impacted area) and Laguna Garzón (control) to analyze the presence of mutagenic agents in the former site through comet assay. Cells from organisms of the impacted area showed significantly higher levels of genetic damage than those obtained in the control population, measured by percentage of DNA in the tail. Although preliminary, this approach supports the idea that H. cf. australis could be used as a sentinel to evaluate the presence of mutagenic agents in estuarine environments, alerting to the impact of contamination in its early stages

Response of estuarine free-living nematode assemblages to organic enrichment:an experimental approach

Organic enrichment, especially from anthropogenic sources, is one of the currentthreats to coastal marine biodiversity. Organic enrichment occurs mainly in sheltered soft bottoms,characterized by fine sediments, and results in multiple changes in the benthic habitat, includinghypoxia and an increased concentration of compounds that are toxic to marine invertebrates. Wereport on the results of a microcosm-based experiment (duration = 30 d), quantifying the effects oforganic enrichment on taxonomic and functional diversity of nematode assemblages from anopen/closed coastal lagoon of South America (Rocha Lagoon, Uruguay). In open/closed lagoons,the input of organic matter becomes a major disturbance due the limitation in water renewal. Inour experiment, enrichment led to reductions in abundance, richness and trophic diversity of thenematode assemblage. Rapid reductions in total abundance (after 4 d) were registered, while richnessdecreased only towards the end of the experiment (~30 d). Trophic changes were characterizedby loss of predators/omnivores and dominance of selective deposit-feeders and epigrowthfeeders.By contrast, we did not find any selective effect of enrichment associated with life historytraits (e.g. maturity index). Overall, these findings have 2 important implications for the conservationand monitoring of the health of coastal lagoons: first, monitoring of nematode assemblages atthe genus level is sufficient to detect enrichment effects; second, an index of trophic diversitywould be a good indicator of the effects of enrichment on natural communities.Fil: Kandratavicius, Noelia. Universidad de la República de Uruguay; UruguayFil: Pastor, Catalina Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; ArgentinaFil: Venturini, Natalia. Universidad de la República de Uruguay; UruguayFil: Giménez, Luis. Bangor University; Reino UnidoFil: Rodriguez, Marcel. Universidad de la República de Uruguay; UruguayFil: Muniz, Pablo. Universidad de la República de Uruguay; Urugua

Biogeochemistry of surface sediments in an Antarctic nearshore area affected by recent glacier retreat: Collins Harbour, King George Island

Biochemical composition of sedimentary organic matter, grain size, major and trace elements were analysed at 10 sampling stations in Collins Harbour, Maxwell Bay, to evaluate sources of particulate material in the seafloor. Surface sediment samples were taken with a grab, during the ANTAR XXV expedition in January 2018, onboard the BAP Carrasco from the Peruvian Navy. Coarse sediment fractions decreased, while mud content increased towards the centre of the bay. Positive correlation between mud and the biopolymeric carbon (BPC) indicated depositional conditions and organic material accumulation in the deepest central area. Proteins (PRT) predominated over other biochemical classes contributing to labile organic carbon, followed by lipids (LIP) and carbohydrates (CHO). PRT positive correlation with Ba, Ca and Al indicated that labile organic carbon inputs derived from marine primary production. Whereas, PRT positive correlation with K and Ti suggested also the influence of terrestrial supply through Collins Glacier meltwater runoff. Mn/Ti, Mn/Al and Fe/Al ratios decreased towards the centre of the bay, while the Ba/Al ratio showed the opposite trend. This distributional pattern suggested the diminish of glacial and terrigenous sedimentation towards the deepest central area of the bay, with the increment of marine particulate material deposition and accumulation. Igeo values between 0 and 1 showed unpolluted conditions in Collins Harbour for Cr, Ni, Cu, Zn, As and Pb, which concentrations may reflect background values for this area. Natural inputs from weathering, glacial runoff and marine primary production are main sources of particulate material in Collins Harbour, with none detected anthropogenic contributions

Pathophysiology of mood disorders in temporal lobe epilepsy

Objective: There is accumulating evidence that the limbic system is pathologically involved in cases of psychiatric comorbidities in temporal lobe epilepsy (TLE) patients. Our objective was to develop a conceptual framework describing how neuropathological, neurochemical and electrophysiological aspects might contribute to the development of psychiatric symptoms in TLE and the putative neurobiological mechanisms that cause mood disorders in this patient subgroup. Methods: In this review, clinical, experimental and neuropathological findings, as well as neurochemical features of the limbic system were examined together to enhance our understanding of the association between TLE and psychiatric comorbidities. Finally, the value of animal models in epilepsy and mood disorders was discussed. Conclusions: TLE and psychiatric symptoms coexist more frequently than chance would predict. Alterations and neurotransmission disturbance among critical anatomical networks, and impaired or aberrant plastic changes might predispose patients with TLE to mood disorders. Clinical and experimental studies of the effects of seizures on behavior and electrophysiological patterns may offer a model of how limbic seizures increase the vulnerability of TLE patients to precipitants of psychiatric symptoms.FAPESPPROEXCNPqFAEP

Testing for nematode–granulometry relationships

The majority of studies have advocated that diversity of marine nematodes increases with increasing sediment grain size, although the opposite trend has also been suggested. The controversy is partially caused by not taking into account the effect of density on patterns of diversity and by analyzing datasets from different environments. The present study investigated nematode assemblages from sediments varying from very fine sand (mean grain size of 0.12 mm) to very coarse sand (1 mm) in shallow sublittoral marine environments. Contrary to previous studies, species richness was constant along the granulometric spectrum, despite significant changes in composition. The dominant genera were separated into five groups according to their optimum distribution and there was little overlap between these groups. Concepts from the niche theory explain to some extent the observed patterns. For instance, some of the coexisting genera were from different feeding types

Variación en pequeña escala de la estructura horizontal y vertical de comunidades macrobentónicas en una laguna costera del Atlántico Sudoccidental = Small-scale variation of the horizontal and vertical structure of macrobenthic communities in a coastal lagoon of the southwestern Atlantic

La Laguna de Rocha forma parte de la cadena de lagunas costeras que se extienden por la costa atlántica uruguaya y se continúa por el sur de Brasil. Presenta una dinámica ecológica compleja debido al gradiente marino-salobre. La macrofauna bentónica es un componente importante de estos ambientes estuariales que se ve afectada por la compleja dinámica del mismo. Analizamos cómo afectan las lenguas de arena (acumulaciones de arena perpendiculares a la barra) a la fauna macrobentónica. Se buscó establecer la relación del macrobentos con variables ambientales, a una escala vertical (estratos dentro del sedimento), y horizontal (a un lado y al otro de las lenguas), además de evaluar la influencia de la distancia a la intrusión marina. En todos los puntos de muestreo los parámetros ambientales (materia orgánica, fósforo total, oxígeno disuelto, clorofila-ay feopigmentos) presentaron una tendencia vertical (disminución hacia el fondo) y el macrobentos se relacionó con estos cambios. Se observó la dominancia de Heleobia australis, Nephtys fluviatilisy Heteromastus similisen diferentes estaciones y estratos. Existe una partición espacial de los recursos reflejada por estos cambios de dominancia, mientras quela distribución vertical de la comunidad macrobentónica responde tanto a las condiciones bióticas como a las ambientales

Biogeochemical and oceanographic conditions provide insights about current status of an Antarctic fjord affected by relatively slow glacial retreat

Comprender el origen, el transporte y el carácter de la materia orgánica que ingresa a los fiordos antárticos es esencial, ya que son componentes importantes del ciclo y presupuesto global del carbono. Se analizaron como indicadores de fuente depósitos macromoleculares de materia orgánica particulada, geoquímica orgánica a granel, elementos principales y traza en sedimentos superficiales de la Bahía de Collins. Como factores de control ambiental se consideraron las condiciones oceanográficas, la batimetría (multihaz) y el tamaño de grano. Las muestras de sedimentos fueron tomadas con una cuchara van Veen, durante la XXV expedición peruana ANTAR (febrero 2018), a bordo del B/O “ BAP Carrasco” de la Armada del Perú. La composición biopolimérica reveló el predominio de materia orgánica marina fresca rica en proteínas en el fondo marino de la Bahía de Collins, lo que denota un recurso alimentario de alta calidad para los heterótrofos bentónicos marinos. Según los valores de Igeo (entre 0 y 1), la Bahía de Collins se puede considerar no contaminada con niveles naturales de As, Cd, Cr, Cu, Fe, Mn, Ni, Pb y Zn. La distribución de la mayoría de estos elementos con un gradiente de disminución desde el fiordo interior poco profundo hacia el fiordo exterior más profundo, sugiere su asociación con la deposición de material detrítico y partículas litogénicas suministradas por la ablación frontal y la escorrentía del glaciar Collins. Esta primera información de referencia integral ayudaría a interpretar las reconstrucciones sedimentarias descendentes y los futuros cambios inducidos por el clima

Psychiatric comorbidities in temporal lobe epilepsy: Possible relationships between psychotic disorders and involvement of limbic circuits

Objective: Mounting evidence suggests that the limbic system is pathologically involved in cases of psychiatric comorbidities in temporal lobe epilepsy (TLE) patients. Our objective was to develop a conceptual framework describing how neuropathological and connectivity changes might contribute to the development of psychosis and to the potential neurobiological mechanisms that cause schizophrenia-like psychosis in TLE patients. Methods: In this review, clinical and neuropathological findings, especially brain circuitry of the limbic system, were examined together to enhance our understanding of the association between TLE and psychosis. Finally, the importance of animal models in epilepsy and psychiatric disorders was discussed. Conclusions: TLE and psychiatric symptoms coexist more frequently than chance would predict. Damage and deregulation among critical anatomical regions, such as the hippocampus, amygdala, thalamus, and the temporal, frontal and cingulate cortices, might predispose TLE brains to psychosis. Studies of the effects of kindling and injection of neuroactive substances on behavior and electrophysiological patterns may offer a model of how limbic seizures in humans increase the vulnerability of TLE patients to psychiatric symptoms.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (National Counsel of Technological and Scientific Development CNPq)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (National Counsel of Technological and Scientific Development - CNPq)Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Norte (FAPERN), BrazilFundacao de Amparo a Pesquisa do Estado do Rio Grande do Norte (FAPERN), Brazi