Isolation of serovars of Salmonella enterica from feces of domestic and wild animals in captivity

Se recolectaron muestras de materia fecal correspondientes a 27 especies de animales en cautiverio pertenecientes al Jardín Zoológico de Mendoza (Argentina), con el fin de encontrar portadores asintomáticos de Salmonella. Las muestras de materia fecal obtenidas con hisopos se sembraron en caldo tetrationato base de MüllerKauffmann y se incubaron a 43 ºC en baño María durante 24 h. Alícuotas de este medio se sembraron en agar xilosalisinadesoxicolato y, finalmente, las colonias desarrolladas se identificaron utilizando pruebas bioquímicas convencionales. Como resultado, se aisló Salmonella serovar Meleagridis a partir de muestras de un oso polar y Salmonella serovar Give a partir de las de un oso pardo y un mono carayá. Ambas serovariedades están asociadas con casos de salmonelosis en humanos.Fecal samples corresponding to 27 species of animals in captivity in the Mendoza Zoo (Argentina) were collected, in order to find asymptomatic carriers of Salmonella. The fecal samples obtained with swabs were seeded in MüllerKauffmann base tetrathionate and incubated at 43 °C in a water bath for 24 h. Then, aliquots of this medium were seeded on xyloselysinedeoxycholate agar and, finally, formed colonies were identified using conventional biochemical tests. As a result, Salmonella serovar Meleagridis was isolated from a polar bear and Salmonella serovar Give from a brown bear and a carayá monkey samples. Both serovars are associated with cases of salmonellosis in humans.Facultad de Ciencias Veterinaria

Efecto de la temperatura y pH sobre la actividad y estabilidad de pectinasas producidas por Bacillus spp.

    Las pectinasas se encuentran ampliamente distribuidas en la naturaleza, como por ejemplo en productos de desecho, y su utilidad industrial es de gran importancia. En la presente investigación se trata de establecer algunos parámetros cinéticos a nivel de laboratorio para la producción de pectinasas por Bacillus spp. Se aisló y seleccionó cultivos puros de Bacillus spp. productores de la enzima a partir de muestras de tierra de cultivo de papa y naranja en medio agar nutritivo con sales y pectina como sustrato, se incubó y se realizó la lectura agregando alícuotas de una solución de lugol y aquellos cultivos que presentaban mayor halo de hidrólisis de pectina fueron seleccionados. Estos cultivos se sembraron en medio líquido nutritivo más sales y pectina y se incubaron por 24 – 48 horas; luego se centrifugaron y se obtuvo el sobrenadante denominado extracto crudo de pectinasa (ECP), el cual sirvió para realizar los ensayos de actividad y estabilidad del ECP a pHs y temperaturas variables.  Se encontró que el pH y temperatura de máxima actividad del ECP está alrededor de 6,5 y 35°C, respectivamente. El ECP es estable a pH 6,5 y 8,5 a 35°C por 120 minutos, lo mismo es cierto a temperatura de 50°C hasta por 129 minutos y pierde su estabilidad a 70°C a los 120 minutos.Palabras clave: Bacillus, pectinasas, pH, temperatura, actividad y estabilidad

Comparing Fatigue when Using Large Horizontal and Vertical Multi-Touch Interaction Displays

We report on a user study that compared muscle fatigue experienced when using a large multi-touch display in horizontal and vertical configurations over a one-hour period. Muscle fatigue is recognized as the reduction in a muscle’s capacity to generate force or power output and was measured objectively and subjectively before and after a puzzle-solving task. While subjective measures showed a significant level of overall arm muscle fatigue after the task for both configurations, objective measures showed a significant level of muscle fatigue on the middle deltoids and the non-dominant extensor digitorum for the vertical configuration only. We discuss the design implications of these findings and suggest relevant future areas of investigation

Social sciences research in neglected tropical diseases 2: A bibliographic analysis

The official published version of the article can be found at the link below.Background There are strong arguments for social science and interdisciplinary research in the neglected tropical diseases. These diseases represent a rich and dynamic interplay between vector, host, and pathogen which occurs within social, physical and biological contexts. The overwhelming sense, however, is that neglected tropical diseases research is a biomedical endeavour largely excluding the social sciences. The purpose of this review is to provide a baseline for discussing the quantum and nature of the science that is being conducted, and the extent to which the social sciences are a part of that. Methods A bibliographic analysis was conducted of neglected tropical diseases related research papers published over the past 10 years in biomedical and social sciences. The analysis had textual and bibliometric facets, and focussed on chikungunya, dengue, visceral leishmaniasis, and onchocerciasis. Results There is substantial variation in the number of publications associated with each disease. The proportion of the research that is social science based appears remarkably consistent (<4%). A textual analysis, however, reveals a degree of misclassification by the abstracting service where a surprising proportion of the "social sciences" research was pure clinical research. Much of the social sciences research also tends to be "hand maiden" research focused on the implementation of biomedical solutions. Conclusion There is little evidence that scientists pay any attention to the complex social, cultural, biological, and environmental dynamic involved in human pathogenesis. There is little investigator driven social science and a poor presence of interdisciplinary science. The research needs more sophisticated funders and priority setters who are not beguiled by uncritical biomedical promises

In vitro activity of ten medicinal plants on ten Streptococcus pneumoniae strains

Introducción: El portador sano es el principal diseminador de las infecciones neumocócicas por la nasofaringe. Una alternativa para combatirlo son las plantas medicinales. Objetivos: Determinar la efectividad de diez plantas medicinales frente a Streptococcus pneumoniae. Diseño: Estudio experimental in vitro. Material biológico: Plantas medicinales y cepas de Streptococcus pneumoniae. Intervenciones: Los extractos de 10 plantas medicinales fueron puestos en contacto in vitro con 10 cepas de Streptococcus pneumoniae. Principales medidas de resultados: Actividad de las plantas medicinales sobre las cepas de Streptococcus pneumoniae. Resultados: almendro y Bellaco caspi fueron las únicas plantas que dieron pequeño halo de inhibición con algunas cepas; con almendro se inhibió dos cepas y con Bellaco caspi, se inhibió siete cepas y tres resultaron resistentes. Estos resultados no tuvieron relación con el serotipo de neumococo ni con los antibióticos utilizados en los antibiogramas realizados previamente. Conclusiones: El Bellaco caspi podría ser una alternativa para atacar al neumococo en la nasofaringe. Pero, por haber presentado resistencia a tres cepas de Streptococcus pneumoniae, antes de usarlo sería conveniente desarrollar un antibiograma de los neumococos contra las plantas medicinales.Introduction: The healthy carrier is the main disseminator of pneumococcal infections through nasopharynx; an alternative for treatment is a medicinal plant. Objectives: To determine the effectivity of ten medicinal plants against Streptococcus pneumoniae. Design: In vitro experimental study. Biologic materials: Medicinal plant extracts and Streptococcus pneumoniae strains. Interventions: Ten medicinal plant extracts were put in contact in vitro with 10 different Streptococcus pneumonia strains. Main outcome measures: Medicinal plant extracts activity against Streptococcus pneumoniae strains. Results: Only almendro y Bellaco caspi showed small inhibition halos with some strains; with almendro two of 10 Pneumococcus strains were inhibited and with Bellaco caspi seven strains were inhibited and three were resistant. These results had no relation either with Pneumococcus serotype or with antibiotics used according to antibiograms. Conclusions: Bellaco caspi could be an alternative for treating nasopharynx Pneumococcus, but due to resistance to three Streptococcus pneumonia strains there is no total guarantee and an antibiogram for pneumococci against medicinal plants is needed

Assessment of exposure to Plasmodium falciparum transmission in a low endemicity area by using multiplex fluorescent microsphere-based serological assays

Background: The evaluation of malaria transmission intensity is a crucial indicator for estimating the burden of malarial disease. In this respect, entomological and parasitological methods present limitations, especially in low transmission areas. The present study used a sensitive multiplex assay to assess the exposure to Plasmodium falciparum infection in children living in an area of low endemicity. In three Senegalese villages, specific antibody (IgG) responses to 13 pre-erythrocytic P. falciparum peptides derived from Lsa1, Lsa3, Glurp, Salsa, Trap, Starp, Csp and Pf11.1 proteins were simultaneously evaluated before (June), at the peak (September) and after (December) the period of malaria transmission, in children aged from 1 to 8 years. Results: Compared to other antigens, a high percentage of seropositivity and specific antibody levels were detected with Glurp, Salsa1, Lsa3NR2, and Lsa1J antigens. The seropositivity increased with age for all tested antigens. Specific IgG levels to Glurp, Salsa1, Lsa3NR2, and Lsa1J were significantly higher in P. falciparum infected children compared to non-infected and this increase is significantly correlated with parasite density. Conclusion: The multiplex assay represents a useful technology for a serological assessment of rapid variations in malaria transmission intensity, especially in a context of low parasite rates. The use of such combined serological markers (i.e. Glurp, Lsa1, Lsa3, and Salsa) could offer the opportunity to examine these variations over time, and to evaluate the efficacy of integrated malaria control strategies

An international code comparison study on coupled thermal, hydrologic and geomechanical processes of natural gas hydrate-bearing sediments

Highlights • Code comparisons build confidence in simulators to model interdependent processes. • International hydrate reservoir simulators are compared over five complex problems. • Geomechanical processes significantly impact response of gas hydrate reservoirs. • Simulators yielded comparable results, however many differences are noted. • Equivalent constitutive models are required to achieve agreement across simulators. Geologic reservoirs containing gas hydrate occur beneath permafrost environments and within marine continental slope sediments, representing a potentially vast natural gas source. Numerical simulators provide scientists and engineers with tools for understanding how production efficiency depends on the numerous, interdependent (coupled) processes associated with potential production strategies for these gas hydrate reservoirs. Confidence in the modeling and forecasting abilities of these gas hydrate reservoir simulators (GHRSs) grows with successful comparisons against laboratory and field test results, but such results are rare, particularly in natural settings. The hydrate community recognized another approach to building confidence in the GHRS: comparing simulation results between independently developed and executed computer codes on structured problems specifically tailored to the interdependent processes relevant for gas hydrate-bearing systems. The United States Department of Energy, National Energy Technology Laboratory, (DOE/NETL), sponsored the first international gas hydrate code comparison study, IGHCCS1, in the early 2000s. IGHCCS1 focused on coupled thermal and hydrologic processes associated with producing gas hydrates from geologic reservoirs via depressurization and thermal stimulation. Subsequently, GHRSs have advanced to model more complex production technologies and incorporate geomechanical processes into the existing framework of coupled thermal and hydrologic modeling. This paper contributes to the validation of these recent GHRS developments by providing results from a second GHRS code comparison study, IGHCCS2, also sponsored by DOE/NETL. IGHCCS2 includes participants from an international collection of universities, research institutes, industry, national laboratories, and national geologic surveys. Study participants developed a series of five benchmark problems principally involving gas hydrate processes with geomechanical components. The five problems range from simple geometries with analytical solutions to a representation of the world's first offshore production test of methane hydrates, which was conducted with the depressurization method off the coast of Japan. To identify strengths and limitations in the various GHRSs, study participants submitted solutions for the benchmark problems and discussed differing results via teleconferences. The GHRSs evolved over the course of IGHCCS2 as researchers modified their simulators to reflect new insights, lessons learned, and suggested performance enhancements. The five benchmark problems, final sample solutions, and lessons learned that are presented here document the study outcomes and serve as a reference guide for developing and testing gas hydrate reservoir simulators

Capsules from Pathogenic and Non-Pathogenic Cryptococcus spp. Manifest Significant Differences in Structure and Ability to Protect against Phagocytic Cells

Capsule production is common among bacterial species, but relatively rare in eukaryotic microorganisms. Members of the fungal Cryptococcus genus are known to produce capsules, which are major determinants of virulence in the highly pathogenic species Cryptococcus neoformans and Cryptococcus gattii. Although the lack of virulence of many species of the Cryptococcus genus can be explained solely by the lack of mammalian thermotolerance, it is uncertain whether the capsules from these organisms are comparable to those of the pathogenic cryptococci. In this study, we compared the characteristic of the capsule from the non-pathogenic environmental yeast Cryptococcus liquefaciens with that of C. neoformans. Microscopic observations revealed that C. liquefaciens has a capsule visible in India ink preparations that was also efficiently labeled by three antibodies generated to specific C. neoformans capsular antigens. Capsular polysaccharides of C. liquefaciens were incorporated onto the cell surface of acapsular C. neoformans mutant cells. Polysaccharide composition determinations in combination with confocal microscopy revealed that C. liquefaciens capsule consisted of mannose, xylose, glucose, glucuronic acid, galactose and N-acetylglucosamine. Physical chemical analysis of the C. liquefaciens polysaccharides in comparison with C. neoformans samples revealed significant differences in viscosity, elastic properties and macromolecular structure parameters of polysaccharide solutions such as rigidity, effective diameter, zeta potential and molecular mass, which nevertheless appeared to be characteristics of linear polysaccharides that also comprise capsular polysaccharide of C. neoformans. The environmental yeast, however, showed enhanced susceptibility to the antimicrobial activity of the environmental phagocytes, suggesting that the C. liquefaciens capsular components are insufficient in protecting yeast cells against killing by amoeba. These results suggest that capsular structures in pathogenic Cryptococcus species and environmental species share similar features, but also manifest significant difference that could influence their potential to virulence

DETC Induces Leishmania Parasite Killing in Human In Vitro and Murine In Vivo Models: A Promising Therapeutic Alternative in Leishmaniasis

Background: Chemotherapy remains the primary tool for treatment and control of human leishmaniasis. However, currently available drugs present serious problems regarding side-effects, variable efficacy, and cost. Affordable and less toxic drugs are urgently needed for leishmaniasis. Methodology/Principal Findings: We demonstrate, by microscopy and viability assays, that superoxide dismutase inhibitor diethyldithiocarbamate (DETC) dose-dependently induces parasite killing (p,0.001) and is able to ??????sterilize?????? Leishmania amazonensis infection at 2 mM in human macrophages in vitro. We also show that DETC-induced superoxide production (p,0.001) and parasite destruction (p,0.05) were reverted by the addition of the antioxidant N-acetylcysteine, indicating that DETC-induced killing occurs through oxidative damage. Furthermore, ultrastructural analysis by electron microscopy demonstrates a rapid and highly selective destruction of amastigotes in the phagosome upon DETC treatment, without any apparent damage to the host cell, including its mitochondria. In addition, DETC significantly induced parasite killing in Leishmania promastigotes in axenic culture. In murine macrophages infected with Leishmania braziliensis, DETC significantly induced in vitro superoxide production (p = 0.0049) and parasite killing (p = 0.0043). In vivo treatment with DETC in BALB/C mice infected with Leishmania braziliensis caused a significant decrease in lesion size (p,0.0001), paralleled by a 100-fold decrease (p = 0.0087) in parasite burden. Conclusions/Significance: Due to its strong leishmanicidal effect in human macrophages in vitro, its in vivo effectiveness in a murine model, and its previously demonstrated in vivo safety profile in HIV treatment, DETC treatment might be considered as a valuable therapeutic option in human leishmaniasis, including HIV/Leishmania co-infection