Habitos alimentarios de Bufo paracnemis (Amphibia, Bufonidae) en el Parana medio, Argentina

On a étudié la composition qualitative et quantitative de l'alimentation de #Bufo parcnemis par l'analyse de 20 estomacs. L'indice d'importance relative, la diversité trophique et l'amplitude de la niche ont été calculés. Les résultats indiquent que #B. paracnemis a un régime omnivore avec une forte dominance insectivore comprenant 20 entités taxonomiques. (Résumé d'auteur

Tiouracilo y sus derivados en el preoperatorio del hipertiroidismo

Últimamente se ha enriquecido la terapéutica de la Endocrinología con el descubrimiento de las drogas tiroinhibídoras del grupo del tiouracilo. De los estudios por los cuáles se ha llegado al conocimiento del tiouracilo y sus propiedades debe destacarse que las observaciones de Chesney y sus colaboradores, en el año 1918 se demostró que el repollo, administrado oomo dieta exclusiva a los conejos, era capaz do producir bocio en estos animales. Esta observación fue confirmada y ampliada por Marine, Bauman y Cipra en 1929, Mac Carrison en 1931, Spende en 1934 y posteriormente otros autores, que demostraron que también otros vegetales oono el repollito de Bruselas, el coliflor, etc. tenían propiedades bocígenas. Este fenómeno también se producía por la administración de hojas y semillas de berzas y semillas de colza, según fue demostrado por Marino y colaboradores en 1929, por Kennedy y Parres en 1941. Con ciertas reglones do la Europa Central, en la que la alimentación con repollo es predominante, se observa bocio endémico según fue comunicado por Suk en 1931.Material digitalizado en SEDICI gracias a la colaboración de la Biblioteca de la Facultad de Ciencias Médicas (UNLP).Facultad de Ciencias Médica

Structure of wetland-breeding anuran assemblages from the southern section of the Paraná river, Argentina

Knowledge of anuran reproduction is necessary to understand the organization of their communities and is a first step in developing management strategies in order to conserve amphibian diversity. We studied the reproduction of anuran species in a wetland reserve – Pre-Delta National Park (PDNP) – on the southern section of the Paraná river in the mideastof Argentina, examining its structure at temporal and spatial levels. We also analysed the influence of environmental factors on breeding activities at habitat and landscape levels. Six waterbodies in the PDNP were monitored from September 2005 to March 2006. Five habitat variables (maximum pond width and length, maximum depth, shore vegetation and presence of predators) and three landscape variables (monthly air temperature, river level and rainfall) were recorded every month and analysed through multivariate analysis. Principal coordinate analysis (PCoA) indicated the existence of four breeding periods. The most frequent breeding call location was the edge of a pond (56.8%), over floating and marsh plants. The presence of tadpole predators and pond width were the main habitat variables that influenced breeding activities. In addition, the number of species with calling males per month was positively correlated with the level of the river which supplies water to ponds. Breeding anuran species co-occurred less often than expected by chance, and exhibited breeding segregation at temporal and spatial scales. The diverse evidence regarding temporal and spatial breeding activities demonstrates the importance of segregation for anuran reproduction in the area studied. We suggest that the nature of breeding interactions can be affected by habitat preference and reproductive strategy, as well as by abiotic (e.g. pond width), biotic (e.g. predators) and landscape (e.g. hydrological variation) variables.Fil: Sanchez, Laura Cecilia. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; ArgentinaFil: Peltzer, Paola. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Escuela Superior de Sanidad; ArgentinaFil: Lajmanovich, Rafael Carlos. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Escuela Superior de Sanidad; Argentin

Feeding habits of Physalaemus biligonigerus (Anura, Leptodactylidae) from soybean field of Córdoba Province, Argentina

Detailed investigation of feeding habits in anurans may help us to understand the ecological significance of them in a particular habitat. In this sense, diet composition of anuran living inside soybean field is scarce. We examined the diet of Physalaemus biligonigerus in soybean field of Córdoba Province, Argentina. A total of 27 frogs (n = 14 females and n = 13 males) were analyzed to assess gastrointestinal contents. Indeed, snout vent length, body mass and sexes were also recorded. A total of 418 prey items was found, being Pheidole sp. (Hymenoptera, Formicidae) and Armadillium vulgare (Crustacea, Isopoda) the most important preys. The diet composition of frog was compared with prey relative abundance in soybean field, estimated by pitfall traps. There were no significant correlation (ô = 0.48, p > 0.05). Selectivity analysis showed positive values for Formicidae and Isoptera. Thus, Isopoda was consumed in the same proportion as occurrence in the environment. No significant differences were detected between females and males diet composition. Finally, we suggest that P. biligonigerus should be considered as potential biocontrol agents of noxious arthropods in soybean field.Fil: Attademo, Andres Maximiliano. Universidad Nacional del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Peltzer, Paola. Universidad Nacional del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lajmanovich, Rafael Carlos. Universidad Nacional del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Consequences of the herbicide-resistant transgenic crop model in Argentina: just a matter of distance?

Los cultivos extensivos de soja transgénica han dejado numerosos pasivos ambientales, como ser desmontes, pérdidas de suelo y biodiversidad, inundaciones, contaminación ambiental y diversas consecuencias socio-económicas y sanitarias. En este contexto, el debate de las “distancias de aplicación” de los agroquímicos a las poblaciones humanas (cuyos rangos tienen una gran variabilidad interjurisdiccional), ocupa gran parte de las agendas políticas actuales. El objetivo del presente aporte es brindar una breve síntesis sobre las principales investigaciones que a lo largo del tiempo han constatado la presencia de residuos de agrotóxicos en distintas matrices ambientales. Además, datos bibliográficos sobre cuáles son las distancias mínimas necesarias para la protección de la salud humana y animal. En último término, realizar algunas reflexiones y recomendaciones concernientes al modelo agroindustrial impuesto y su creciente conflictividad ambiental y a la necesidad de una urgente opción “agroecológica” que promueva la producción de alimentos sin transgénicos y sin agrotóxicos.Extensive crops of GM soybeans produced numerous environmental liabilities, such as clearing, loss of soil and biodiversity, floods, environmental pollution and several socio-economic and health consequences. In this context, the debate about the “distances of application” of agrochemicals to human populations (whose ranks have a great interjurisdictional variability), occupies a large part of the current political agendas. The objective of this contribution is to provide a brief summary of the main investigations that, over time, have confirmed the presence of pesticide residues in different environmental matrices. In addition, bibliographic data on which are the minimum distances necessary for the protection of human and animal health. Finally, make some reflections and recommendations concerning the imposed agribusiness model and its growing environmental conflict and the need for an urgent “agroecological” alternative that promotes the production of food without transgenic and without agrotoxics.Fil: Lajmanovich, Rafael Carlos. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Escuela Superior de Sanidad; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentin

Inhibition and recovery of cholinesterases in Odontophrynus americanus tadpoles exposed to fenitrothion

We determined the levels of brain acetylcholinesterase (AChE) and tail butyrylcholinesterase (BChE) activities in tadpoles of Odontophrynus americanus exposed to a commercial formulation of fenitrothion. The mean brain AChE activities in the controls tadpoles varied from 6.91 to 6.39 µmol min-1 mg-1 protein, whereas tail BChE activities ranged among 0.26 to 0.17 µmol min-1 mg-1 protein; the two sub- lethal concentrations of fenitrothion assayed produced AChE and BChE inhibition (p < 0.01). Brain AChE recovered a substantial level of activity with a maximum of 93.2%; after the transference of tadpoles to a free-pesticide solution, whereas tail BChE recovery showed a smaller increase (39%) in the activity at 168 hr after to transference to clear water. According with our results, we suggest that tadpole’s tail BChE presents higher sensibility than brain AChE.Fil: Lajmanovich, Rafael Carlos. Universidad Nacional del Litoral; ArgentinaFil: Attademo, Andres Maximiliano. Universidad Nacional del Litoral; ArgentinaFil: Peltzer, Paola. Universidad Nacional del Litoral; ArgentinaFil: Junges, Celina Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentin

Acute Toxicity and Sublethal Effects Caused by a Commercial Herbicide Formulated with 2,4-D on Physalaemus albonotatus Tadpoles

The aim of this study was to evaluate the acute and chronic effects caused by exposure to the 2,4 dichlorophenoxyacetic acid (2,4-D)-based commercial herbicide Amina Zamba® on Physalaemus albonotatus tadpoles from Gosner stage 25. The lethal concentration (LC50) was determined after exposure to different concentrations of Amina Zamba® (350 to 2400 mg/L) at 96 h. Sublethal effects were evaluated after chronic exposure to four fractions of the LC50 96h obtained (12.5, 25, 50, and 75% of LC50 96h ) and a control. The biological responses analyzed included survival, growth and development, morphological abnormalities, and histological changes in the liver. The LC50 values of Amina Zamba® at 48, 72, and 96 h were 1040.2, 754.2, and 350 mg/L, respectively. The chronic exposure to the herbicide altered the survival of exposed tadpoles and caused several morphological abnormalities and liver histological alterations, mainly at the highest concentrations tested. Oral disc malformations and intestinal abnormalities were the most frequent abnormalities in all treated tadpoles. Histological alterations observed in the liver structure included hepatocyte vacuolization, enlargement of sinusoids, dilation of blood vessels, and a significant increase in the number of melanomacrophages in tadpoles exposed to 25, 50, and 75% LC50 96h with respect to control (P < 0.05). Furthermore, the treated tadpoles showed an accelerated development rate, reaching Gosner stages 38 and 42 before controls. These results demonstrate that the chronic exposure to this commercial formulation affects the survival, accelerates metamorphosis, and induces morphological abnormalities and liver damage in P. albonotatus tadpoles.Fil: Curi, Lucila Marilén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Laboratorio de Ecotoxicologia; ArgentinaFil: Peltzer, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Laboratorio de Ecotoxicologia; ArgentinaFil: Sandoval, María Teresa. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología; ArgentinaFil: Lajmanovich, Rafael Carlos. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Laboratorio de Ecotoxicologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentin

Albinism in larvae of the Chacoan frog <i>Leptodactylus chaquensis</i> (Anura, Leptodactylidae) from an urban lake from Argentina

We report complete albinism in Leptodactylus chaquensis (Cei, 1950; Amphibia, Anura) larvae. Two foam nests were collected from an urban lake and maintained in outdoor tanks during metamorphosis. Different proportions of albino larvae and metamorphs occurred. This is the first observation of several larvae of L. chaquensis with albinisms from an urban lake with continuous artificial and natural luminosity.Asociación Herpetológica Argentina (AHA

Albinism in larvae of the Chacoan frog <i>Leptodactylus chaquensis</i> (Anura, Leptodactylidae) from an urban lake from Argentina

We report complete albinism in Leptodactylus chaquensis (Cei, 1950; Amphibia, Anura) larvae. Two foam nests were collected from an urban lake and maintained in outdoor tanks during metamorphosis. Different proportions of albino larvae and metamorphs occurred. This is the first observation of several larvae of L. chaquensis with albinisms from an urban lake with continuous artificial and natural luminosity.Asociación Herpetológica Argentina (AHA