Toxicity assessment of biological suspensions using the dielectric impedance spectroscopy technique.

PURPOSE: This article studies the variation of the electromagnetic parameters of a suspension of zebrafish (Danio rerio) embryos to assess its potential applications to toxicological and biomedical research areas. MATERIALS AND METHODS: For this purpose, the dielectric impedance spectroscopy technique is applied to a modified coaxial line enclosing the biological suspension to be characterized in the frequency range from 100 kHz to 100 MHz. The electrical parameters of the suspension under test were obtained by fitting the impedance spectra to the resulted from the simulation of the test fixture using finite elements (FE). RESULTS: Variation of the complex permittivity of the suspensions makes possible to identify viable and non-viable embryos after a toxic exposure, as well as different stages during the blastula period of embryonic development of the zebrafish. CONCLUSIONS: The approach presented here, combining experimental and simulation techniques, may provide a basis for a non-invasive method to assess toxicity in any biological suspension.

Environmental concentrations of the cocaine metabolite benzoylecgonine induced sublethal toxicity in the development of plants but not in a zebrafish embryo-larval model.

Several studies have found cocaine and its main active metabolite benzoylecgonine (BE) in the aquatic environment and drinking water, derived from its consumption by humans as well as the inability of water treatment processes to eliminate it. A few studies have already investigated the ecotoxicology of BE to aquatic invertebrates, but none has still addressed the effects of BE on aquatic vertebrates or vascular plants. The goal of this publication is to provide information on the toxicity of environmental concentrations of BE during animal and vascular plant development, in order to contribute to a better understanding of the potential risk of this substance for the environment. BE induced alterations in mitochondrial activity and DNA levels of fern spores at environmental concentrations (1 ng L(-1)), which could disrupt gametophyte germination. However, BE at concentrations ranging from 1 ng L(-1) to 1 mg L(-1) did not disturb morphogenesis, hatching, heartbeat rate or larval motility in a zebrafish embryo-larval model. Adverse effects on ferns agree with the allelophathic role described for alkaloids and their unspecific interference with plant germination. Therefore, the anthropogenic dispersion of alkaloid allelochemicals may pose a risk for biodiversity and irrigated food production that should be further investigated.

Informatic resources useful for the development of biomedical applications of nanomaterials and their toxicological evaluation / Recursos informáticos útiles en el desarrollo de aplicaciones biomédicas de nanomateriales y su evaluación toxicológica

The need for tools to process all the information generated in the field of nanotechnology has led to the development of a new discipline known as nanoinformatics. In the coming years, it is expected to have databases with information, not only on the physicochemical properties of nanomaterials, but also with information on the potential interactions with environment and biological systems, which will enable search for new biomedical applications of nanomaterials, without forgetting their toxicological aspects. In this review, various standardization resources, ontologies, databases, initiatives and partnerships that will help manage the information generated on nanomaterials are presented, especially those useful in biomedical research and the toxicology of nanomaterials. In addition, other complementary web resources are described with the aim of facilitating the process of self-learning and the development of curriculum contents of nanotechnology in higher education centers (AU)

La necesidad de herramientas informáticas para procesar toda la información generada en el ámbito de la nanotecnología ha originado el desarrollo de una nueva disciplina conocida como nanoinformática. En los próximos años es esperable poder disponer de bases de datos con información, no sólo de las propiedades físico-químicas de los nanomateriales, sino también con información de sus posibles interacciones con el medio ambiente y sistemas biológicos, lo que favorecerá la investigación de nuevas aplicaciones biomédicas de los nanomateriales, sin olvidar sus aspectos toxicológicos. En este artículo se presentan diversos recursos de estandarización, ontologías, bases de datos, iniciativas y colaboraciones que ayudan a gestionar la información generada sobre nanomateriales, especialmente orientados a favorecer la Investigación biomédica y la toxicología de los nanomateriales. Además, se presentan otros recursos web complementarios que facilitarán el proceso de autoaprendizaje y el desarrollo de contenidos curriculares en escuelas superiores y facultades, útiles en la formación de esta nueva disciplina, denominada nanotecnología (AU)

Efectos letales y subletales de nanopartículas y material soluble de oro en el desarrollo de embriones de pez cebra / The lethal and sub-lethal effects of nanoparticulated and soluble gold on the development of zebrafish embryos

La toxicidad de las nanopartículas de oro (AuNP) en el desarrollo de pez cebra resulta un tanto controvertida, ya que algunos autores demuestran su inocuidad, mientras que otros autores advierten de la presencia de efectos tóxicos. Por otro lado, la toxicidad del material base de la AuNP en solución aún no se ha investigado, aunque generalmente se requiera. Por consiguiente, el objetivo de este estudio fue investigar los efectos de la exposición de AuNP y el oro soluble en embriones de pez cebra, aportando reflexiones sobre la toxicidad de AuNP. Para ello, se llevaron a cabo ensayos toxicológicos en embriones de pez cebra con AuNP sin recubrimiento y recubiertas con ácido hialurónico (12,8 ± 1,6 nm, TEM), así como el material base (HAuCl4) de dichas AuNP. Los resultados demuestran que las AuNP no fueron tóxicas durante las primeras fases del desarrollo de los embriones (0-48 h). Por otro lado, el HAuCl4 resultó ser letal a concentraciones > 64,1 mg/L. A concentraciones subletales (48,1-0,7 mg/L), el HAuCl4 no alteró el desarrollo ni la actividad motora o cardiaca, aunque redujo notablemente la capacidad de eclosión a > 5.7 mg/L, situándose el NOAEC en 2,7 mg/L. Teniendo en cuenta nuestros resultados y los encontrados por otros autores, se puede concluir que la superficie de carga y en menor medida el tamaño de las AuNP resultaron ser los factores clave para explicar la toxicidad de la AuNP. Nuestros resultados también confirmaron que este modelo, con embriones de pez cebra, es adecuado para el estudio de toxicidad de las nanopartículas, siempre y cuando éstas estén completamente caracterizadas antes y durante el ensayo de toxicidad (AU)

Toxicity of gold nanoparticles (AuNPs) on zebrafish development is a rather controversial aspect in literature, and the investigation of the bulk material has not been considered yet, even though it is generally required. Therefore, we investigated the potential adverse effects of AuNPs and soluble gold on zebrafish embryos, while trying to find a rationale for gold nanoparticle toxicity. For such a purpose, uncoated and coated with hyaluronic acid AuNPs (12.8 ± 1.6 nm, TEM) and the bulk material (HAuCl4) were tested for their toxicity in zebrafish embryos. Results showed that the AuNPs were non-toxic for the zebrafish development during exposure (0-48h). Soluble gold (HAuCl4) was lethal at > 64.1 mg/L. At sublethal concentrations (48.1-0.7 mg/L) HAuCl4 did not alter embryo development, spontaneous movements or heartbeat rate, but the hatching ability was affected at > 5.7 mg/L, resulting in a NOAEC of 2.7 mg/L. According to our data and others found in scientific literature, it can be concluded that surface charge and, to a lesser extent, the size of the gold nanoparticles are key factors to explain toxicity of gold nanoparticles. Our results also confirmed that this model is suitable for studying nanoparticle toxicity, although the nanoparticles themselves should be fully characterised before and during the toxicity test (AU)

Effect of long-term exposure to simazine on histopathology, hematological, and biochemical parameters in Cyprinus carpio.

We investigated if residues of simazine in the natural waters would cause histological, hematological, and biochemical alterations in carps from contaminated areas in Badajoz (Spain). Some necrotic foci in kidney and liver, hepatitis, and hepatic steatosis were detected. No changes on measured hematological and biochemical parameters between fish from reference and contaminated ponds were observed. To assess if simazine exposure was the cause of these observations carps were exposed in the laboratory to simazine (45 microg/L) for 90 days. Some results obtained in the field were confirmed in laboratory, such as necrosis in kidney and liver and hepatic steatosis. Globular eosinophilic foci in kidney and a slight decrease of the hematocrit were also detected. These changes were moderate and indicative of an adaptation of the fish to the toxic stress caused by exposure to low simazine concentrations.

Effect of long-term exposure to simazine on brain and muscle acetylcholinesterase activity of common carp (Cyprinus carpio).

Several water-contamination incidents with simazine have occurred in the province of Badajoz (Spain), due to its excessive use for controlling weeds in olive trees and vineyards. Simazine residues were also detected in drinking water, increasing public health concern. However, little is known on the effects that low levels of simazine pose to environment organisms. We investigated if residues of simazine in the natural waters would affect brain and muscle acetylcholinesterase activity in common carps captured in areas in which simazine residues were detected at average levels of 4.5 microg/L. Results confirmed depression on brain and muscle acetylcholinesterase activity of 20% and 29%, respectively, in carps inhabiting one of the simazine-contaminated ponds, termed "Molinos de Matachel." To assess the biological significance of this finding, we developed a controlled laboratory study in which carps were exposed to simazine at 45 microg/L (10-fold that of the natural water levels) for 90 days. The results obtained in the field study were not confirmed in our laboratory experiment, since carps did not show evidence or brain or muscle acetylcholinesterase activity depression for the duration of the experiment, and therefore, we can conclude that acetylcholinesterase depression found in carps collected in "Molinos de Matachel" should be ascribed to other compounds or mixtures of xenobiotics.

Lead exposition by gunshot ingestion in red-legged partridge (Alectoris rufa).

Absorption of low concentrations of lead may result in a wide range of sublethal effects in birds. Although waterfowl appear the most severely affected group for this heavy metal, leadpoisoning-mortality has been observed in a wide variety of bird species, ie raptors and upland game birds. In this present work, hepatic lead levels in different red-legged partridges are presented to indicate threshold values which could help in future toxicological studies when considering the lack of information about lead poisoning of such birds in the wild.