Influence of microplastics on the toxicity of chlorpyrifos and mercury on the marine microalgae Rhodomonas lens

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGThe growing use of plastics, including microplastics (MPs), has enhanced their potential release into aquatic environments, where microalgae represent the basis of food webs. Due to their physicochemical properties, MPs may act as carriers of organic and inorganic pollutants. The present study aimed to determine the toxicity of polyethylene MPs (plain and oxidized) and the model pollutants chlorpyrifos (CPF) and mercury (Hg) on the red microalgae Rhodomonas lens, to contribute to the understanding of the effects of MPs and associated pollutants on marine ecosystems, including the role of MPs as vectors of potentially harmful pollutants to marine food webs. R. lens cultures were exposed to MPs (1–1000 μg/L; 25–24,750 particles/mL), CPF (1–4900 μg/L), Hg (1–500 μg/L), and to CPF- and Hg-loaded MPs, for 96 h. Average specific growth rate (ASGR, day−1), cellular viability and pigment concentration (chlorophyll a, c2 and carotenoids) were measured at 48 and 96 h. No significant effects were observed on the growth pattern of the microalgae after 96-h exposure to plain and oxidized MPs. However, a significant increase in cell concentration was detected after 48-h exposure to plain MPs. A decrease of the ASGR was noticed after exposure to CPF, Hg and to CPF/Hg-loaded MPs, whereas viability was affected by exposure to MPs, CPF and Hg, alone and in combination. Chlorophyll a and c2 significantly decreased when microalgae were exposed to plain MPs and CPF, while both pigments significantly increased when exposed to CPF-loaded MPs. Similarly, chlorophyll and carotenoids content significantly decreased after exposure to Hg, whereas a significant increase in chlorophyll a was observed after 48-h exposure to Hg-loaded MPs, at the higher tested concentration. Overall, the presence of MPs modulates the toxicity of Hg and CPF to these microalgae, decreasing the toxic effects on R. lens, probably due to a lower bioavailability of the contaminants

Análisis de la localización subcelular de la proteína VCC de Arabidopsis y del efecto de las condiciones de cultivo sobre el fenotipo del mutante vcc-2

Se han publicado descripciones discrepantes del fenotipo del mutante vasculature complexity and connectivity-2 (vcc-2) y de la localización subcelular de la proteína VCC de Arabidopsis. Roschzttardtz et al. (2014) y Yanagisawa et al. (2021) afirmaron que el patrón de venación de los cotiledones de vcc-2 es más simple e inconexo que el silvestre, y que VCC se localiza en la membrana celular. Según Wilson-Sánchez et al. (2018), las hojas de vcc-2 muestran asimetría bilateral, y VCC radica en el retículo endoplásmico. Hemos intentado establecer si tales discrepancias se deben a diferentes condiciones de cultivo o a diseños erróneos de los transgenes obtenidos para la visualización de proteínas de fusión entre VCC y una proteína fluorescente. Hemos comprobado que la temperatura y el fotoperiodo no modifican el patrón de venación de los cotiledones ni la simetría bilateral de las hojas de los mutantes estudiados, excepto vcc-2, cuya asimetría bilateral se incrementó en medios gelificados con Gelrite. Nuestro análisis mediante microscopía confocal de superresolución reveló que la proteína de fusión VCC:CFP es aparentemente citoplásmica. También hemos diseñado e iniciado la construcción de las fusiones traduccionales 35Spro:GFP:VCC (con la GFP unida al extremo amino de VCC en la proteína de fusión resultante) y 35Spro:VCC:YFP (con una proteína fluorescente más fotoestable y adecuada para la nanoscopía que la GFP).Two distinct descriptions have been published of the phenotype of the vasculature complexity and connectivity-2 (vcc-2) Arabidopsis mutant, as well as of the subcellular localization of the VCC protein. Roschzttardtz et al. (2014) and Yanagisawa et al. (2021) claimed that the venation pattern of vcc-2 cotyledons is simpler and disconnected compared to wild type, and that VCC localizes at the cell membrane. According to Wilson-Sánchez et al. (2018), vcc-2 leaves exhibit bilateral asymmetry, and VCC localizes at the endoplasmic reticulum. We attempted to establish whether these discrepancies are due to different growth conditions or defective design of the transgenes used for obtaining and visualizing VCC fusion proteins. We confirmed that temperature and photoperiod do not modify the venation pattern of cotyledons or the bilateral symmetry of the studied mutants, except for vcc-2, whose leaf bilateral asymmetry increased in media gelified with Gelrite. Our super-resolution confocal microscopy analysis revealed that VCC:CFP is apparently cytoplasmic. We also designed and initiated the construction of the translational fusions 35Spro:GFP:VCC (with GFP attached to the N-terminus of VCC in the resulting fusion protein) and 35Spro:VCC:YFP (with a fluorescent protein more photostable and suitable for nanoscopy than GFP)

Comparative assessment of microplastics and microalgae as vectors of mercury and chlorpyrifos in the copepod Acartia tonsa

Microplastics (MPs) raise concerns not only as pollutants themselves, but also due to their ability to act as vectors of pollutants adsorbed from seawater, transferring them to marine organisms. However, the relevance of MPs as carriers of pollutants compared to microalgae needs further exploration. This study compared the role of MPs (2–10 μm non-oxidized and 10–15 μm oxidized high-density polyethylene) and natural organic particles (Rhodomonas lens microalgae, MA) as carriers of mercury (Hg, 2.3 μg Hg/L) and chlorpyrifos (CPF, 1.0 μg CPF/L) to adult Acartia tonsa copepods, after 24–48 h exposure. Dose-response experiments were first performed with adult female copepods exposed to oxidized MPs (0.25–4.0 mg/L), waterborne Hg (0.01–10.0 μg/L) and Ox MPs + Hg (0.25–4.0 mg oxidized MPs/L + 0.50–8.0 μg Hg/L) for 48 h, to complement previous studies that focused on the pesticide CPF. Effects were evaluated with four replicates for physiological and reproductive responses (6 females/replicate), biochemical techniques (40 individuals/replicate) and Hg/CPF bioaccumulation measurements (1000 individuals/replicate). Copepods accumulated Hg/CPF similarly from dissolved pollutants (6204 ± 2265 ng Hg/g and 1251 ± 646 ng CPF/g) and loaded MPs (3125 ± 1389 ng Hg/g and 1156 ± 266 ng CPF/g), but significantly less from loaded MA (21 ± 8 ng Hg/g and 173 ± 80 ng CPF/g). After 24–48 h, copepods exposed to MPs + Hg/CPF showed generally greater biological effects than those exposed to dissolved Hg/CPF or to MA + Hg/CPF, although differences were not statistically significant. MA + CPF had significantly lower AChE inhibition (1073.4 nmol min−1 mg−1) and MA + Hg lower GRx induction (48.8 nmol min−1 mg−1) compared to MPs + Hg/CPF and dissolved Hg/CPF (182.8–236.4 nmol min−1 mg−1 of AChE and 74.1–101.7 nmol min−1 mg−1 of GRx). Principal component analysis suggested different modes of action for Hg and CPF.Xunta de GaliciaAgencia Estatal de InvestigaciónUniversidade de Vigo/CISU

Genotyping of Giardia intestinalis from Schoolchildren in Honduras

This study aimed to identify the circulating genotypes of Giardia intestinalis in Honduran schoolchildren. Of a total of 242 fecal samples, 7.4% showed G. intestinalis cysts by microscopy. All positive samples amplified the tpi gene. Three samples amplified genotype A, four samples amplified genotype B, while 11 samples amplified both genotypes. These results suggest the presence of mixed infections or recombinant strains within the analyzed population. The sequences of the 18Sr gene confirmed for the first time in Honduras the presence of both genotypes (A and B) of Giardia intestinalis causing human infections

Genotyping of Giardia intestinalis from Schoolchildren in Honduras

This study aimed to identify the circulating genotypes of Giardia intestinalis in Honduran schoolchildren. Of a total of 242 fecal samples, 7.4% showed G. intestinalis cysts by microscopy. All positive samples amplified the tpi gene. Three samples amplified genotype A, four samples amplified genotype B, while 11 samples amplified both genotypes. These results suggest the presence of mixed infections or recombinant strains within the analyzed population. The sequences of the 18Sr gene confirmed for the first time in Honduras the presence of both genotypes (A and B) of Giardia intestinalis causing human infections

Role of UV radiation and oxidation on polyethylene micro- and nanoplastics: impacts on cadmium sorption, bioaccumulation, and toxicity in fish intestinal cells

This study investigated the role of ultraviolet (UV) radiation and oxidation in high-density polyethylene microplastics (2–15 μm) and nanoplastics (0.2–9.9 μm) (NMPs) on particle chemistry, morphology, and reactivity with cadmium (Cd). Additionally, toxicity of NMPs alone and with Cd was evaluated using RTgutGC cells, a model of the rainbow trout (Oncorhynchus mykiss) intestine. The role on NMPs on Cd bioaccumulation in RTgutGC cells was also evaluated. Dynamic light scattering indicated that after UV radiation NPs agglomerated size increased from 0.8 to 28 µm, and to 8 µm when Cd was added. Oxidized MPs agglomerated size increased from 11 and 7 to 46 and 27 µm in non-UV- and UV-aged oxidized MPs when adding Cd, respectively. Cd-coated particles exhibited generally significantly higher zeta potential than non-Cd-coated particles, while attenuated total reflectance–Fourier transform infrared spectroscopy showed that the functional chemistry of the particles was oxidized and modified after being exposed to UV radiation. Presence of NMPs resulted in a significant decrease in Cd bioaccumulation in RTgutGC cells (100.5–87.9 ng Cd/mg protein) compared to Cd alone (138.1 ng Cd/mg protein), although this was not quite significant for co-exposures with UV-aged NPs (105.7 ng Cd/mg protein). No toxicity was observed in RTgutGC cells exposed to NMPs alone for 24 h. Moreover, co-exposures with Cd indicated that NMPs reduce the toxicity of Cd. Altogether these results show that UV aging enhances NMP surface reactivity, increasing Cd absorption in solution, which resulted in a reduction in Cd bioavailability and toxicity.Xunta de GaliciaNational Institute on Minority Health and Health Disparities (EE.UU.) | Ref. P50MD015706National Institute of Environmental Health Sciences (EE.UU.) | Ref. 1R15ES034901-01Universidade de Vigo/CISU

Estudio de necesidades de formación de profesores que imparten estadística en carreras del área social

Este trabajo, de corte cuantitativo, exploratorio y tipo encuesta, presenta las características y necesidades de formación profesional (inicial y permanente) y de práctica docente (estrategias de enseñanza, recursos materiales y estrategias de evaluación) de 46 profesores que imparten estadística en alguna carrera del área de humanidades y ciencias de la conducta, de la Cd. de Mérida, Yucatán. Con base en las respuestas al “cuestionario para identificar y detectar las características y necesidades de los profesores de estadística”, se concluye que es necesario utilizar diversas estrategias de enseñanza, materiales y recursos con base en la investigación generada en la educación estadística. El estudio sustenta la necesidad de un programa ad hoc de formación de profesores de estadística a través de variadas y nuevas formas de formación (ej. comunidades de práctica)

Exercise tolerance in dogs with pulmonary hypertension treated with sildenafil

El estudio buscó establecer el efecto del sildenafil sobre la distancia recorrida en la prueba de marcha de seis minutos (6MWT) en caninos sanos y con hipertensión pulmonar (HP) sobre la frecuencia cardiaca (FC) y respiratoria (FR) en una zona de gran altitud (2650 m sobre el nivel del mar). Un grupo de nueve perros con diagnóstico de HP y otro de 10 perros clínicamente sanos hicieron la caminata en una pista plana de 30 metros, sin control de temperatura y humedad. Al finalizar se la prueba se les administró 1 mg/kg de sildenafil oral. Una hora después, se repitió la prueba. Antes y después de cada prueba se midió la FC y FR mediante auscultación. Los perros con HP caminaron 470 ± 122.6 y 407.8 ± 137.4 m antes y después de sildenafil, respectivamente (p=0.027). Asimismo, la FR fue más alta después de la prueba que antes de empezar (p<0.05). El grupo de caninos sanos caminó 560 ± 55 y 613 ± 36 m antes y después de sildenafil, respectivamente (p=0.03) y redujo la FR antes y después de la segunda prueba donde recibieron sildenafil. Los perros con HP redujeron su tolerancia al ejercicio de manera drástica y presentaron aumentos de FR, mientras que los caninos sanos aumentaron la distancia recorrida con, posiblemente, menos requerimiento de oxígeno. Estos resultados ponen en duda la utilidad del sildenafil para la reducción de signos clínicos en caninos con hipertensión pulmonar en zonas de gran altura y sugieren su uso para mejorar la tolerancia aguda al ejercicio en caninos sanos en zonas de altura

High Levels of Tetrodotoxin (TTX) in Trumpet Shell Charonia lampas from the Portuguese Coast

Tetrodotoxin (TTX) is a potent neurotoxin, considered an emerging toxin in Europe where recently a safety limit of 44 µg TTX kg-1 was recommended by authorities. In this study, three specimens of the large gastropod trumpet shell Charonia lampas bought in a market in south Portugal were analyzed using a neuroblastoma cell (N2a) based assay and by LC-MS/MS. N2a toxicity was observed in the viscera of two individuals analyzed and LC-MS/MS showed very high concentrations of TTX (42.1 mg kg-1) and 4,9-anhydroTTX (56.3 mg kg-1). A third compound with m/z 318 and structurally related with TTX was observed. In the edible portion, i.e., the muscle, toxin levels were below the EFSA recommended limit. This study shows that trumpet shell marine snails are seafood species that may reach the markets containing low TTX levels in the edible portion but containing very high levels of TTX in non-edible portion raising concerns regarding food safety if a proper evisceration is not carried out by consumers. These results highlight the need for better understanding TTX variability in this gastropod species, which is critical to developing a proper legal framework for resources management ensuring seafood safety, and the introduction of these gastropods in the markets.UID/Multi/04326/2020info:eu-repo/semantics/publishedVersio

Innovaciones en la Enseñanza de la Robótica: Realidad Aumentada

Augmented Reality (AR) is a technological tool that provides interactive experiences to the user by overlapping virtual objects in a real environment. This paper presents a tool developed using augmented reality to study and teach robotic manipulators, focused on universities without the economic resources to acquire a serial manipulator. Three programs were developed that allow the student to visualize and rectify essential concepts of robotics such as the transformation of coordinate systems, Denavit - Hartenberg methodology, and configuration of a robotic manipulator, among others. The application allows the student to interact virtually with different manipulators, control the robot’s joints using the keyboard, and visualize real-time distances and parameters concerning a fixed coordinate system on the screen. Considering that the manipulators are rendered, it is possible to perform path planning and collision analysis on a path given by the user. The application is easily modifiable, including new manipulators and developing didactic strategies for students.La Realidad Aumentada (RA) es una tecnología que proporciona experiencias interactivas al usuario superponiendo objetos virtuales en un ambiente real. En este trabajo se presenta una herramienta desarrollada usando realidad aumentada para el estudio y enseñanza de manipuladores robóticos, dirigida especialmente a universidades sin los recursos económicos para adquirir un manipulador serial. Fueron desarrollados tres programas que le permiten al estudiante visualizar y rectificar conceptos esenciales de la robótica como: transformación de sistemas coordenados, metodología de Denavit – Hartenberg, configuración de un manipulador robótico, entre otros. El aplicativo permite al estudiante interactuar de manera virtual con diferentes manipuladores, controlando mediante el uso del teclado las articulaciones del robot, y visualizando en pantalla en tiempo real distancias y parámetros respecto a un sistema coordenado fijo. Teniendo en cuenta que los manipuladores se encuentran renderizados, es posible realizar análisis de trayectoria y colisiones en un recorrido dado por el usuario. El aplicativo es fácilmente modificable, lo que permite la inclusión de nuevos manipuladores y el desarrollo de estrategias innovadoras