Unexpected different chemoselectivity in the aerobic oxidation of methylated planar catechin and bent epicatechin derivatives catalysed by the Trametes villosa laccase/1-hydroxybenzotriazole system

Unreported methylated catechin and epicatechin derivatives 5 and 6 were synthesized by an oxa-Pictet- Spengler reaction. Catechin 5 shows the B and C rings coplanar because of the formation of a trans junction between the C ring and the newly generated six-term cycle D, in turn condensed to ring B. In contrast, epicatechin 6 presents a bent geometry due to the establishment of a cis junction between the C ring and the newly formed cycle D. The oxidation of compounds 5 and 6 in the presence of the Trametes villosa laccase/1-hydroxybenzotriazole (HBT) system was investigated under aerobic conditions in both a biphasic system and a reverse micelle. The unexpected different chemoselective oxidation at the benzylic position of catechin and epicatechin derivatives 5 and 6 has been rationalized using a molecular modelling approach. These results demonstrate that the Trametes villosa laccase/HBT system represents a useful tool to functionalize the C-2 or C-4 position of phenolic compounds depending on the structural features

Fortaleciendo los sistemas tradicionales de producción de semilla en los Andes en Perú.

Los cultivos alimenticios en el Perú han estado históricamente asociados a la pequeña agricultura andina, caracterizada por predios muy pequeños (<3ha), tecnificación tradicional y producción destinada principalmente al autoconsumo y una pequeña proporción para la venta y producción de semilla. El Centro Internacional de la Papa (CIP) a través de su programa Papa Andina/INCOPA promovió una serie de innovaciones que han permitido revalorizar la biodiversidad de la papa y organizar cadenas productivas inclusivas para articular a pequeños productores pobres alto andinos a nuevos mercados. Sin embargo, esta innovación generó demanda por semilla de variedades nativas con potencial de mercado, la cual no ha podido ser satisfecha debido a que el sistema formal de semilla no abastece la demanda interna y las variedades nativas no han sido priorizadas por dicho sistema. Como alternativa, los proyectos del CIP como InnovAndes (Junín y Huancavelica) y McKnight (Pasco), están promoviendo esquemas no convencionales como una alternativa flexible para mejorar los sistemas tradicionales de producción de semilla y responder a la demanda de los pequeños productores. En ambos casos, en las comunidades participantes se organizaron comités de gestión de semillas, que fueron capacitados en técnicas de multiplicación de semilla e identificación de plagas para tener a su cargo la producción de semilla básica en campos semilleros e invernaderos empleando la técnica de selección positiva. La capacitación se realizó a través de escuelas de campo de agricultores (ECA) semilleristas. Como resultado de la intervención, del Proyecto McKnight en las comunidades de La Quinua y Quichas (Pasco) se logró reducir en más del 92% la incidencia de virus (PVX y PVS), enfermedades (P. infestans) e insectos (Epitrix spp, y Diabrótica spp) que afectan la calidad de la semilla, lográndose aumentar el rendimiento promedio de tubérculos en 53%. En este proyecto, el comité de gestión de semillas se constituyó como empresa y cuentan con un invernadero de aeroponia para producir semilla prebásicaa bajo costo, habiendo producido hasta la fecha 54,000 tuberculillos de 6 variedades nativas. En el marco del proyecto Innovandes, los productores de Chicche y Pomamanta (Junín) aprendieron la técnica convencional de propagación y multiplicación de semilla pre-básica en sus respectivos invernaderos. En 2011 la producción fue en total 20,574 tuberculillos de variedades nativas con demanda en el mercado, con lo que han constituido un fondo rotatorio de semilla de las variedades Leona y Cceccorani de uso en gastronomía y la industria, respectivamente. Los resultados indican que la producción de semilla pre-básica en combinación con la técnica de selección positiva ayudará a gestar un mercado regional de semilla de calidad, con posibilidades de evolucionar hacia un esquema o modelo no convencional, similar al de semilla de calidad declarada (QDS)

Lower Richness of Small Wild Mammal Species and Chagas Disease Risk

A new epidemiological scenario involving the oral transmission of Chagas disease, mainly in the Amazon basin, requires innovative control measures. Geospatial analyses of the Trypanosoma cruzi transmission cycle in the wild mammals have been scarce. We applied interpolation and map algebra methods to evaluate mammalian fauna variables related to small wild mammals and the T. cruzi infection pattern in dogs to identify hotspot areas of transmission. We also evaluated the use of dogs as sentinels of epidemiological risk of Chagas disease. Dogs (n = 649) were examined by two parasitological and three distinct serological assays. kDNA amplification was performed in patent infections, although the infection was mainly sub-patent in dogs. The distribution of T. cruzi infection in dogs was not homogeneous, ranging from 11–89% in different localities. The interpolation method and map algebra were employed to test the associations between the lower richness in mammal species and the risk of exposure of dogs to T. cruzi infection. Geospatial analysis indicated that the reduction of the mammal fauna (richness and abundance) was associated with higher parasitemia in small wild mammals and higher exposure of dogs to infection. A Generalized Linear Model (GLM) demonstrated that species richness and positive hemocultures in wild mammals were associated with T. cruzi infection in dogs. Domestic canine infection rates differed significantly between areas with and without Chagas disease outbreaks (Chi-squared test). Geospatial analysis by interpolation and map algebra methods proved to be a powerful tool in the evaluation of areas of T. cruzi transmission. Dog infection was shown to not only be an efficient indicator of reduction of wild mammalian fauna richness but to also act as a signal for the presence of small wild mammals with high parasitemia. The lower richness of small mammal species is discussed as a risk factor for the re-emergence of Chagas disease

Temporal differences in blood meal detection from the midguts of Triatoma infestans

We used genus/species specific PCRs to determine the temporal persistence of host DNA in Triatoma infestans experimentally fed on blood from six common vertebrate species: humans, domestic dogs, guinea pigs, chickens, mice, and pigs. Twenty third or fourth instar nymphs per animal group were allowed to feed to engorgement, followed by fasting-maintenance in the insectary. At 7, 14, 21, or 28 days post-feeding, the midgut contents from five triatomines per group were tested with the respective PCR assay. DNA from all vertebrate species was detected in at least four of five study nymphs at seven and 14 days post-feeding. DNA of humans, domestic dogs, guinea pigs, pigs, and chickens were more successfully detected (80-100%) through day 21, and less successfully (20-100%) at day 28. Findings demonstrate that species-specific PCRs can consistently identify feeding sources of T. infestans within two weeks, a biologically relevant time interval

Risk factors associated with Trypanosoma cruziexposure in domestic dogs from a rural community in Panama

Chagas disease, caused by Trypanosoma cruzi infection, is a zoonosis of humans, wild and domestic mammals,including dogs. In Panama, the main T. cruzi vector is Rhodnius pallescens, a triatomine bug whose main naturalhabitat is the royal palm, Attalea butyracea. In this paper, we present results from three T. cruzi serological tests(immunochromatographic dipstick, indirect immunofluorescence and ELISA) performed in 51 dogs from 24 housesin Trinidad de Las Minas, western Panama. We found that nine dogs were seropositive (17.6% prevalence). Dogswere 1.6 times more likely to become T. cruzi seropositive with each year of age and 11.6 times if royal palms wherepresent in the peridomiciliary area of the dog’s household or its two nearest neighbours. Mouse-baited-adhesivetraps were employed to evaluate 12 peridomestic royal palms. All palms were found infested with R. pallescens withan average of 25.50 triatomines captured per palm. Of 35 adult bugs analysed, 88.6% showed protozoa flagellates intheir intestinal contents. In addition, dogs were five times more likely to be infected by the presence of an additionaldomestic animal species in the dog’s peridomiciliary environment. Our results suggest that interventions focused onroyal palms might reduce the exposure to T. cruzi infection