Éxito reproductivo en Mus musculus (Rodentia) expuesto a olores de conespecíficos y hacinamiento bajo condiciones de laboratorio.

To assess the use of conspecific's odors for controlling commensal Mus musculus, we studied the effect of overcrowding on the reproductive success of females in laboratory conditions. While pregnancy rates, litter size, the weight at birth and survival until weaning did not differ between overcrowding and control groups, the time elapsed until pregnancy was lower for the control group, while the mean weight and the total number of offspring surviving at weaning were higher in the control group. Control females produced a mean of 1.25 offspring, while overcrowded females produced 0.6. A lower weight of the offspring of crowded females may affect their future chances of survival and reproduction.Para evaluar el uso de olores de conespecíficos para el control de M. musculus comensales, estudiamos el efecto del hacinamiento sobre el éxito reproductivo de hembras en condiciones de laboratorio. La tasa de preñez, el tamaño de camada, el peso al nacer y la supervivencia al destete no difirieron significativamente entre hembras hacinadas y controles. El tiempo transcurrido hasta la preñez fue menor en el grupo control, mientras que el peso promedio y el número de crías sobrevivientes al destete fueron mayores. Las hembras control produjeron un promedio de 1,25 crías y las hacinadas 0,6. El menor peso de las crías de las hembras hacinadas podría afectar su supervivencia y futura reproducción.Fil: Burroni, Nora. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Loetti, María V.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Busch, Maria. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

A natural resource-based view of climate change: innovation challenges in the automobile industry

In recent years, uncertainty about climate change policies has deeply altered the competitive landscape of the automobile industry, and highlighted the key role that companies can play in reducing global CO2 emissions through technological innovation. Given the complexity of the innovation process in this industry, mainly due to an interactive relationship with the market, this study adopts a socio-technical transition perspective in order to understand the type of technological innovations that automobile companies have developed for reducing CO2 emissions from their products during a period of regulatory uncertainty. The Natural-Resource-Based View is used as a novel framework to categorize technological innovations into two important sets: product stewardship and clean technology. Product stewardship innovations are characterized by incremental changes in product components, with no substantial modifications of the core product concept. Clean technology innovations are characterized by significant alterations to existing product functionalities, infrastructure and consumer patterns, and imply major restructuring of both manufacturing processes and market acceptance. Under regulatory uncertainty, findings show that significant reductions of CO2 emissions from vehicles have been due to clean technology innovations. The benefits from clean technologies persist over time. In addition, complementarities between product stewardship and clean technology innovations have occurred, with positive effects on further CO2 emission reductions. These latter benefits, however, show only short-term effects, suggesting that continuous innovation in product stewardship is necessary in the next few years in this industry to survive in a carbon-constrained market.This work was supported by Grant #ECO2013-46091-P from Spanish Ministry of Economy and Competitiveness. Part of this work was performed while the first author was visiting faculty (2012-2014) at Pompeu Fabra University, Department of Economics and Business, Barcelona (Spain)

Helminth communities and host-parasite relationships in argentine brown rat (Rattus norvegicus)

The aims of this research were: 1) to determine the helminth parasite fauna of seventy two Rattus norvegicus (Berkenhout, 1769) individuals inhabiting poultry farms in the Pampean region of Argentina; 2) to examine the relationship between parasitism and individual characteristics of the hosts, and 3) to analyze the associations among helminths. The study was carried out in twenty-four poultry farms from autumn 2000 to winter 2001. Nematodes were found in the intestine or caecum rectum of the 74 % of rats and cestodes were found along all the intestine of the 28 % of rats. Heterakis spumosa (Travassos 1914) was a central species, whereas Syphacia muris, Yamaguti 1941, Nippostrongylus brasiliensis (Travassos 1914) and Hymenolepis diminuta (Rudolphi 1819) were satellite species. Helminths do not affect rat survival and growth of rats. Rats parasitized with H. spumosa and H. diminuta were larger and older than non-parasitized rats. The intensity of infection with H. spumosa significantly increased with rat age. Rats parasitized with Nippostrongylus brasiliensis and Syphacia muris did not differ in size and age with respect to non-parasitized ones. The mean intensity of infections per host was 33.74, 74.28, higher than 200, and 3.10 for H. spumosa, S. muris, N. brasiliensis and H. diminuta, respectively. The mean intensity of infection with H. spumosa was higher in summer than in the other seasons, while the higher mean intensity of infection with N. brasiliensis and S. muris occurred in autumn. Infections with Heterakis spumosa and Syphacia muris, and with Syphacia muris and Nippostrongylus brasiliensis were independent; while Heterakis spumosa and Nippostrongylus brasiliensis were negatively associated.Centro de Estudios Parasitológicos y de VectoresFacultad de Ciencias Naturales y Muse

Helminth communities and host-parasite relationships in argentine brown rat (Rattus norvegicus)

The aims of this research were: 1) to determine the helminth parasite fauna of seventy two Rattus norvegicus (Berkenhout, 1769) individuals inhabiting poultry farms in the Pampean region of Argentina; 2) to examine the relationship between parasitism and individual characteristics of the hosts, and 3) to analyze the associations among helminths. The study was carried out in twenty-four poultry farms from autumn 2000 to winter 2001. Nematodes were found in the intestine or caecum rectum of the 74 % of rats and cestodes were found along all the intestine of the 28 % of rats. Heterakis spumosa (Travassos 1914) was a central species, whereas Syphacia muris, Yamaguti 1941, Nippostrongylus brasiliensis (Travassos 1914) and Hymenolepis diminuta (Rudolphi 1819) were satellite species. Helminths do not affect rat survival and growth of rats. Rats parasitized with H. spumosa and H. diminuta were larger and older than non-parasitized rats. The intensity of infection with H. spumosa significantly increased with rat age. Rats parasitized with Nippostrongylus brasiliensis and Syphacia muris did not differ in size and age with respect to non-parasitized ones. The mean intensity of infections per host was 33.74, 74.28, higher than 200, and 3.10 for H. spumosa, S. muris, N. brasiliensis and H. diminuta, respectively. The mean intensity of infection with H. spumosa was higher in summer than in the other seasons, while the higher mean intensity of infection with N. brasiliensis and S. muris occurred in autumn. Infections with Heterakis spumosa and Syphacia muris, and with Syphacia muris and Nippostrongylus brasiliensis were independent; while Heterakis spumosa and Nippostrongylus brasiliensis were negatively associated.Centro de Estudios Parasitológicos y de VectoresFacultad de Ciencias Naturales y Muse

Physicochemical, thermal and rheological properties of isolated Argentina quinoa starch

The aim of the present study was to evaluate the physicochemical, thermal and pasting properties of the starch of six quinoa genotypes native to the northwest of Argentina. The genotypes belonging to two genotype groups, highlands and dry valley, were grown in Jujuy, Argentina. Significant differences among genotypes were observed (P < 0.05) in amylose content, swelling power, water-binding capacity, thermal and pasting properties. In the different genotypes, the starch was characterized by a typical A-type X-ray diffraction pattern, with relative crystallinity ranging between 26.1 and 28.5%. Granule-bound starch synthase (GBSS), which is the single enzyme responsible for amylose biosynthesis, was also identified, with the 67- and 58-kDa quinoa polypeptides corresponding to the full-length and mature GBSS proteins. Studies of the pasting properties showed that the starch of the genotypes from the highlands had lower peak viscosity and lower breakdown parameter than that of the genotypes from the dry valleys. The results showed that the genotypic background and the environment influence the pasting curves. The novel findings discussed in this study constitute a starting point for research focusing on incorporating innovative technologies in the food and biomaterials industry.Fil: Lopez Fernandez, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Rodríguez, Silvio David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Favre, Leonardo Cristian. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias. Instituto de Tecnología de Alimentos y Procesos Quimicos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Tecnología de Alimentos y Procesos Quimicos.; ArgentinaFil: Busch, Verónica María. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias. Instituto de Tecnología de Alimentos y Procesos Quimicos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Tecnología de Alimentos y Procesos Quimicos.; ArgentinaFil: Buera, Maria del Pilar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias. Instituto de Tecnología de Alimentos y Procesos Quimicos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Tecnología de Alimentos y Procesos Quimicos.; Argentin

Hantavirus in rodents of Buenos Aires Province: are seroprevalence and abundance related?

Oligoryzomys flavescens and Akodon azarae are two rodent species living in agroecosystems of the Pampean region. O. flavescens is a reservoir of the Lechiguanas genotype, associated with Hantavirus Pulmonary Syndrome, whereas Akodon azarae is a reservoir of the Pergamino genotype, which has not been associated with human cases. Our objective was to evaluate whether there is a relationship between abundance and seroprevalence in both rodent species, as this may help to identify situations of high risk of exposure to hantavirus for humans. Eleven longitudinal rodent capture-mark-recapture surveys were conducted in three railway embankments in agricultural landscapes (Exaltación de la Cruz Departament, Buenos Aires province, Argentina), from 2014 through 2016. The trapping effort was 1800 trap-nights per survey. During these surveys, demographic data and blood samples were collected. Blood samples were analyzed by means of ELISAs to determine the presence of hantavirus-specific antibodies. For each rodent species, the relationship between seroprevalence and its abundance was assessed through logit-linked binomial generalized linear models using the number of infected individuals by sampling session as the response variable (i.e., successees, with the corresponding number of tested blood samples per group as trials). Models containing the species’ MNA as a predictor and the null models were evaluated. Using a multi-model approach, averaged parameters and their relative importance were calculated using Akaike weights (AIC). The main finding in this work was that both A. azarae and O. flavescens exhibit a negative relationship between prevalence and abundance. A possible explanation for this result is that populations reach their smaller numbers when these consist mainly of overwintering adults, which had longer exposures with higher chances of becoming infected, whereas larger populations are observed soon after the reproductive season, when new recruits are unlikely to be infected yet. Thus, the effect of prevalence and abundance on the risk of human exposure could be compensatory. This suggests that there would be no particular season of increased risk; prevention and surveillance should be permanent.Para acceder a la videoconferencia completa, hacer clic en "Enlace externo".Sociedad Latinoamericana de Ecología de Vectore

Calidad e innovación en docencia en la USC: integración de las competencias informacionales en la guía docente. La experiencia en la asignatura de Biología

Within the framework of the European Higher Education Area, as Transversal competences that students should possess at the end of their Degree studies, there is training in informational competences (IC). The IC main objective is the acquisition of skills and abilities for access and use of information. An online IC Course taught in collaboration with the University Library as part of the Teaching Program of a 1st course discipline, was very well followed by the students. Students participation was high, and a big percentage of them passed the examinations. A substantial improvement in the presentation of the works and the bibliography was observed

Helminth communities and host-parasite relationships in argentine brown rat (Rattus norvegicus)

The aims of this research were: 1) to determine the helminth parasite fauna of seventy two Rattus norvegicus (Berkenhout, 1769) individuals inhabiting poultry farms in the Pampean region of Argentina; 2) to examine the relationship between parasitism and individual characteristics of the hosts, and 3) to analyze the associations among helminths. The study was carried out in twenty-four poultry farms from autumn 2000 to winter 2001. Nematodes were found in the intestine or caecum rectum of the 74 % of rats and cestodes were found along all the intestine of the 28 % of rats. Heterakis spumosa (Travassos 1914) was a central species, whereas Syphacia muris, Yamaguti 1941, Nippostrongylus brasiliensis (Travassos 1914) and Hymenolepis diminuta (Rudolphi 1819) were satellite species. Helminths do not affect rat survival and growth of rats. Rats parasitized with H. spumosa and H. diminuta were larger and older than non-parasitized rats. The intensity of infection with H. spumosa significantly increased with rat age. Rats parasitized with Nippostrongylus brasiliensis and Syphacia muris did not differ in size and age with respect to non-parasitized ones. The mean intensity of infections per host was 33.74, 74.28, higher than 200, and 3.10 for H. spumosa, S. muris, N. brasiliensis and H. diminuta, respectively. The mean intensity of infection with H. spumosa was higher in summer than in the other seasons, while the higher mean intensity of infection with N. brasiliensis and S. muris occurred in autumn. Infections with Heterakis spumosa and Syphacia muris, and with Syphacia muris and Nippostrongylus brasiliensis were independent; while Heterakis spumosa and Nippostrongylus brasiliensis were negatively associated.Centro de Estudios Parasitológicos y de VectoresFacultad de Ciencias Naturales y Muse

A Microbial Nitrogen Engine Modulated by Bacteriosyncytia in Hexactinellid Sponges: Ecological Implications for Deep-Sea Communities

Hexactinellid sponges are common in the deep sea, but their functional integration into those ecosystems remains poorly understood. The phylogenetically related species Schaudinnia rosea and Vazella pourtalesii were herein incubated for nitrogen and phosphorous, returning markedly different nutrient fluxes. Transmission electron microscopy (TEM) revealed S. rosea to host a low abundance of extracellular microbes, while Vazella pourtalesii showed higher microbial abundance and hosted most microbes within bacteriosyncytia, a novel feature for Hexactinellida. Amplicon sequences of the microbiome corroborated large between-species differences, also between the sponges and the seawater of their habitats. Metagenome-assembled genome of the V. pourtalesii microbiota revealed genes coding for enzymes operating in nitrification, denitrification, dissimilatory nitrate reduction to ammonium, nitrogen fixation, and ammonia/ammonium assimilation. In the nitrification and denitrification pathways some enzymes were missing, but alternative bridging routes allow the microbiota to close a N cycle in the holobiont. Interconnections between aerobic and anaerobic pathways may facilitate the sponges to withstand the low-oxygen conditions of deep-sea habitats. Importantly, various N pathways coupled to generate ammonium, which, through assimilation, fosters the growth of the sponge microbiota. TEM showed that the farmed microbiota is digested by the sponge cells, becoming an internal food source. This microbial farming demands more ammonium that can be provided internally by the host sponges and some 2.6 million kg of ammonium from the seawater become annually consumed by the aggregations of V. pourtalesii. Such ammonium removal is likely impairing the development of the free-living bacterioplankton and the survival chances of other sponge species that feed on bacterioplankton. Such nutritional competitive exclusion would favor the monospecific character of the V. pourtalesii aggregations. These aggregations also affect the surrounding environment through an annual release of 27.3 million kg of nitrite and, in smaller quantities, of nitrate and phosphate. The complex metabolic integration among the microbiota and the sponge suggests that the holobiont depends critically on the correct functioning of its N-driven microbial engine. The metabolic intertwining is so delicate that it changed after moving the sponges out of their habitat for a few days, a serious warning on the conservation needs of these sponge aggregations

Coproparasitological study of Akodon azarae (Rodentia, Cricetidae) in Pampas agroecosystems

Este trabajo describe los huevos hallados en heces frescas (depuestas en las trampas) del ratón de campo Akodon azarae (Fischer) en bordes de campos de cultivo de Exaltación de la Cruz (Buenos Aires, Argentina). Las muestras fueron fijadas en solución SAF, procesadas por la técnica de Ritchie modificada y observadas al microscopio óptico. Las características morfológicas y morfométricas de los huevos permitieron identificar los nematodes Stilestrongylus cf. azarai (prevalencia: P = 63%), Trichuris cf. laevitestis (P = 35%) y cf. Spirurida (P = 10%), y al cestode Rodentolepis cf. nana (P = 5%). Se discute, a la luz de la bibliografía disponible sobre huevos de helmintos parásitos de A. azarae y otros roedores de zonas cercanas al área de estudio, la determinación taxonómica de las especies identificadas en base a las características observadas.This work describes eggs found in fresh faeces (deposited in traps) of the Pampean grassland rodent Akodon azarae (Fischer) inhabiting cultivated field edges in Exaltación de la Cruz (Buenos Aires, Argentina). Samples were fixed in SAF solution, processed by the modified Ritchie technique and observed under optical microscope. Morphological and morphometric characteristics of eggs allowed us to identify the nematodes Stilestrongylus cf. azarai (prevalence: P = 63%), Trichuris cf. laevitestis (P = 35%) and cf. Spirurida (P = 10%), and the cestode Rodentolepis cf. nana (P = 5%). We discussed, taking in account the literature available about parasitic helminths of A. azarae and other rodents in the region, the taxonomic determination of the species identified based on the characteristics observed.Asociación Parasitológica Argentin