Estrogenic compounds as exogenous modulators of physiological functions in molluscs: Signaling pathways and biological responses

Molluscs have been widely utilized to evaluate the effects of estrogenic compounds, one of the most widespread classes of Endocrine Disrupting Chemicals-EDCs. However, knowledge on steroid signaling and metabolism in molluscs has considerably increased in the last decade: from these studies, a considerable debate emerged on the role of 'natural' steroids in physiology, in particular in reproduction, of this invertebrate group. In this work, available information on the effects and mechanisms of action of estrogens in molluscs will be reviewed, with particular emphasis on bivalves that, widespread in aquatic ecosystems, are most likely affected by exposure to estrogenic EDCs. Recent advances in steroid uptake and metabolism, and estrogen receptors-ERs in molluscs, as well as in estrogen signaling in vertebrates, will be considered. The results so far obtained with 17\u3b2-estradiol and different estrogenic compounds in the model bivalve Mytilus spp., demonstrate specific effects on immune function, development and metabolism. Transcriptomic data reveal non genomic estrogen signaling pathways in mussel tissues that are supported by new observations at the cellular level. In vitro and in vivo data show, through independent lines of evidence, that estrogens act through non-genomic signaling pathways in bivalves. In this light, regardless of whether molluscs synthesize estrogens de novo or not, and despite their ERs are not directly activated by ligand binding, estrogens can interact with multiple signaling components, leading to modulation of different physiological functions. Increasing knowledge in endocrine physiology of molluscs will provide a framework for a better evaluation and interpretation of data on the impact of estrogenic EDCs in this invertebrate group

Photocatalytic Fe-doped n-TiO2: From synthesis to utilization of in vitro cell models for screening human and environmental nanosafety

The utilization of different types nanomaterials (NMs) in environmental remediation and wastewatertreatment requires information on the potential harmful effects on human and environmental health. Inthis light, the utilization of human cell models together with cells from lower organisms, representativeof different environmental compartments, could represent a valuable tool for the in vitro screening of thepotential toxicity of different NMs used in nanoremediation. Among NMs, n-TiO2, because of its peculiaroptical and chemical properties, is widely applied for photosensitized UV oxidation of organic pollutants.Moreover, development in design of metal- and non metal- doped TiO2 with extended photocatalyticactivity in the visible region represents the subject of ongoing research

Physiological Roles of Serotonin in Bivalves: Possible Interference by Environmental Chemicals Resulting in Neuroendocrine Disruption

Contaminants of Emerging Concerns (CECs) are defined as chemicals not commonly monitored in aquatic ecosystems, but with the potential to cause adverse effects on biota. CECs include Endocrine Disrupting Chemicals (EDCs) and Neuro-Endocrine disruptors (NEDs) of vertebrates. However, most invertebrates only rely on neuroendocrine systems to maintain homeostatic processes. Although conserved neuroendocrine components have been characterized in ecologically relevant groups, limited knowledge on invertebrate neuroendocrinology makes it difficult to define EDCs and NEDs in most species. The monoamine serotonin (5-hydroxytryptamine, 5-HT) acts both as a neurotransmitter and as a peripheral hormone in mammals. In molluscs, 5-HT is involved in multiple physiological roles and molecular components of the serotonergic system have been identified. This review is focused on the effects of CECs on the serotonergic system of bivalve molluscs. Bivalves are widespread in all aquatic environments, estuarine and coastal areas in particular, where they are exposed to a variety of chemicals. In bivalves, 5-HT is involved in gametogenesis and spawning, oocyte maturation and sperm motility, regulates heart function, gill ciliary beating, mantle/siphon function, the ‘‘catch’’ state of smooth muscle and immune responses. Components of 5-HT transduction (receptors and signaling pathways) are being identified in several bivalve species. Different CECs have been shown to affect bivalve serotonergic system. This particularly applies to antidepressants, among the most commonly detected human pharmaceuticals in the aquatic environment. In particular, selective serotonin reuptake inhibitors (SSRIs) are frequently detected in seawater and in bivalve tissues. Information available on the effects and mechanisms of action of SSRIs on the serotonergic system of adult bivalves is summarized. Data are also reported on the effects of CECs on development of neuroendocrine pathways of early larval stages, in particular on the effects of model EDCs in the marine mussel Mytilus galloprovincialis. Overall, available data point at the serotonergic system as a sensitive target for neuroendocrine disruption in bivalves. The results contribute drawing Adverse Outcome Pathways (AOPs) for model EDCs and SSRIs in larvae and adults. However, basic research on neuroendocrine signaling is still needed to evaluate the potential impact of neuroendocrine disruptors in key invertebrate groups of aquatic ecosystems

Herramientas de gestión: relación entre concentraciones de material particulado fracción gruesa (MP10) y material particulado fracción fina (MP2.5) en calidad del aire

Los sistemas más habituales de monitoreo de la calidad del aire proporcionan datos basados en la medición del MP10 respecto a otros tamaños del material particulado. Como consecuencia, la mayoría de los estudios epidemiológicos utilizan el valor de concentración de la fracción MP10 como indicador de la exposición de la población. Sin embargo, numerosos trabajos científicos dan evidencia de mayores efectos sobre la salud asociados al MP2.5 en comparación con el anterior. En tal sentido contar con mediciones de esta fracción fina (MP2.5) en calidad de aire resulta de suma relevancia. En la práctica, no es sencillo acceder a esta información; principalmente por los altos costos que implican estas determinaciones. Por ende, se destaca la importancia de contar con un factor que relacione ambos parámetros, tal como lo ha estimado la Organización Mundial de la Salud (OMS), obteniendo un valor aproximado a 0.5 (MP2.5/MP10). Este número corresponde a zonas urbanas de los países en desarrollo. En el presente trabajo se estiman factores locales, en base a mediciones de MP10 y MP2.5, con el propósito de caracterizar las zonas urbanas evaluadas, acceder a un diagnóstico más preciso de distribución de la fracción fina y constituir así una herramienta de gestión

Impact of bisphenol A (BPA) on early embryo development in the marine mussel Mytilus galloprovincialis: Effects on gene transcription.

Bisphenol A (BPA), a monomer used in plastic manufacturing, is weakly estrogenic and a potential endocrine disruptor in mammals. Although it degrades quickly, it is pseudo-persistent in the environment because of continual inputs, with reported concentrations in aquatic environments between 0.0005 and 12 \u3bcg/L. BPA represents a potential concern for aquatic ecosystems, as shown by its reproductive and developmental effects in aquatic vertebrates. In invertebrates, endocrine-related effects of BPA were observed in different species and experimental conditions, with often conflicting results, indicating that the sensitivity to this compound can vary considerably among related taxa. In the marine mussel Mytilus galloprovincialis BPA was recently shown to affect early development at environmental concentrations. In this work, the possible effects of BPA on mussel embryos were investigated at the molecular level by evaluating transcription of 13 genes, selected on the basis of their biological functions in adult mussels. Gene expression was first evaluated in trocophorae and D-veligers (24 and 48 h post fertilization) grown in physiological conditions, in comparison with unfertilized eggs. Basal expressions showed a general up-regulation during development, with distinct transcript levels in trocophorae and D-veligers. Exposure of fertilized eggs to BPA (10 \u3bcg/L) induced a general upregulation at 24 h pf, followed by down regulation at 48 h pf. Mytilus Estrogen Receptors, serotonin receptor and genes involved in biomineralization (Carbonic Anydrase and Extrapallial Protein) were the most affected by BPA exposure. At 48 h pf, changes in gene expression were associated with irregularities in shell formation, as shown by scanning electron microscopy (SEM), indicating that the formation of the first shelled embryo, a key step in mussel development, represents a sensitive target for BPA. Similar results were obtained with the natural estrogen 17\u3b2-estradiol. The results demonstrate that BPA and E2 can affect Mytilus early development through dysregulation of gene transcription

Modelos utilizados en emergencias

Los modelos aplicados en emergencias son muy utilizados como modelos de respuesta y herramientas de planificación. En esta sección se desarrollarán los conceptos básicos de dichos modelos. Se abordarán casos de aplicación real utilizando el modelo ALOHA. Se explicarán niveles de preocupación: AEGL y otros, como así también la interpretación de resultados.Facultad de Ciencias Exacta

Photocatalytic Fe-doped n-TiO2: From synthesis to utilization of in vitro cell models for screening human and environmental nanosafety

The utilization of different types nanomaterials (NMs) in environmental remediation and wastewater treatment requires information on the potential harmful effects on human and environmental health. In this light, the utilization of human cell models together with cells from lower organisms, representative of different environmental compartments, could represent a valuable tool for the in vitro screening of the potential toxicity of different NMs used in nanoremediation. Among NMs, n-TiO2, because of its peculiar optical and chemical properties, is widely applied for photosensitized UV oxidation of organic pollutants. Moreover, development in design of metal- and non metal- doped TiO2 with extended photocatalytic activity in the visible region represents the subject of ongoing research. In this work, the cytotoxic effects of three different types of recently synthetized Fe-doped n-TiO2 were compared in two cell models widely utilized for screening cellular toxicity of NMs in humans and aquatic organisms, human vascular endothelial cells (HECV) and immune cells (hemocytes) of the marine invertebrate, the mussel Mytilus spp, respectively. Parallel studies were carried out using N-doped n-TiO2. The results indicate both distinct and common behavior (agglomeration state) in different media (human cell culture medium and mussel hemolymph serum) and biological effects (cytotoxicity, nitric oxide production) of different types of doped- n-TiO2 in different cell models. Although in vitro studies represent a first step in the toxicological assessment of NMs, studies comparing their effects on human and aquatic invertebrate cells that take into account the effects of different exposure media represent an useful tool for evaluating potential cytotoxicity of those NMs, like TiO2-based photocatalytic NMs, widely applied in environmental remediation, and whose potential risks are poorly understood

Responses of Mytilus galloprovincialis to challenge with the emerging marine pathogen Vibrio coralliilyticus

Vibrio coralliilyticus has emerged as a coral pathogen of concern throughout the Indo-Pacific reef. The interest towards understanding its ecology and pathogenic potential has increased since V. coralliilyticus was shown to be strongly virulent also for other species; in particular, it represents a serious threat for bivalve aquaculture, being one of the most important emerging pathogen responsible for oyster larval mortalities worldwide. V. coralliilyticus has a tightly regulated temperature-dependent virulence and it has been related to mass mortalities events of benthic invertebrates also in the temperate northwestern Mediterranean Sea. However, no data are available on the effects of V. coralliilyticus in the mussel Mytilus galloprovincialis, the most abundant aquacultured species in this area. In this work, responses of M. galloprovincialis to challenge with V. coralliilyticus (ATCC BAA-450) were investigated. In vitro, short term responses of mussel hemocytes were evaluated in terms of lysosomal membrane stability, bactericidal activity, lysozyme release, ROS and NO production, and ultrastructural changes, evaluated by TEM. In vivo, hemolymph parameters were measured in mussels challenged with V. coralliilyticus at 24h p.i. Moreover, the effects of V. coralliilyticus on mussel early embryo development (at 48 hpf) were evaluated. The results show that both in vitro and in vivo, mussels were unable to activate immune response towards V. coralliilyticus, and that challenge mainly induced lysosomal stress in the hemocytes. Moreover, V. coralliilyticus showed a strong and concentration-dependent embryotoxicity. Overall, the results indicate that, although M. galloprovincialis is considered a resistant species to vibrio infections, the emerging pathogen V. coralliilyticus can represent a potential threat to mussel aquaculture

Herramientas de control cultural para el manejo de artrópodos plaga en agricultura extensiva

Existe una creciente necesidad de profundizar el conocimiento y la divulgación de estrategias de manejo de adversidades bióticas en cultivos extensivos que excluyan el uso de agroquímicos. En el Módulo Productivo Periurbano (MPP) de INTA EEA Marcos Juárez se relevaron poblaciones de artrópodos y se utilizaron prácticas culturales tendientes a disminuir el desarrollo y supervivencia de las plagas, o hacer que el cultivo sea menos susceptible al ataque de las mismas. Los objetivos perseguidos fueron evaluar dichas prácticas para el manejo de poblaciones de artrópodos plaga en los cultivos de trigo, soja y maíz, y medir su impacto sobre poblaciones de enemigos naturales. Según el cultivo y la plaga en cuestión (orugas defoliadoras, bicho bolita, gorgojo del macollo del trigo, oruga cogollera) se utilizaron como estrategias la incorporación de cultivo de cobertura, la disminución del espaciamiento entre hileras, el aumento de la densidad de siembra, diferentes rotaciones y fechas de siembra. En todos los casos, la utilización de prácticas culturales constituyó una alternativa viable para el manejo de artrópodos plaga en cultivos extensivos.EEA Marcos JuárezFil: Balbi, Emilia Inés. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez; Argentina.Fil: Defagot, Melisa Ana Velia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez; Argentina.Fil: Gadban, Laura Carolina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez; Argentina

Resposta de Populações de Plantas Daninhas ao Plantio e a Taxas Reduzidas de Herbicida e Nitrogênio na Produção de Trigo (Triticum aestivum)

Field experiments were carried out in 1999 and 2000 to investigate the effects of conventional (CT) and no-tillage (NT) systems, interacting with three herbicide dose levels and three nitrogen (N) levels on weed growth and wheat production of two varieties. There was a higher grain yield for NT system compared with CT in one year. CT weed biomass was lower than from NT weed biomass, in both varieties. No differences on wheat biomass and grain yield were observed between full and reduced herbicide rates. N fertilizer increased wheat biomass and grain yield significantly. Only N medium level had an effect upon weed biomass with respect to non-fertilized plots, while the highest fertilization rate lowered weed biomass. Conventional tillage, reduced herbicide rates and nitrogen fertilization were effective ways of limiting weed production in wheat.Experimentos foram conduzidos sob condições de campo em 1999 e 2000 a fim de investigar os efeitos dos plantios convencional (PC) e direto (PD), em combinação com três doses de herbicidas e três de nitrogênio (N), no crescimento de plantas daninhas e produção de duas variedades de trigo. Foi observada produção maior de grãos PD, comparado ao PC, durante um ano. A biomassa das plantas daninhas no PC foi menor do que no PD, para as duas variedades. Nenhuma diferença em biomassa e produção de grãos de trigo foi observada entre as doses de herbicida integral e reduzida. N aumentou a biomassa do trigo e produção de grãos significativamente. Apenas o nível médio de N teve efeito sobre a biomassa das plantas daninhas em relação à não-aplicação de N, enquanto uma taxa maior de N diminuiu a biomassa das plantas daninhas. No plantio convencional, doses reduzidas de herbicida e aplicação de N foram efetivos na limitação do crescimento das plantas daninhas no cultivo de trigo.Facultad de Ciencias Agrarias y Forestale