Genetic complexity of miscanthus cell wall composition and biomass quality for biofuels

BACKGROUND: Miscanthus sinensis is a high yielding perennial grass species with great potential as a bioenergy feedstock. One of the challenges that currently impedes commercial cellulosic biofuel production is the technical difficulty to efficiently convert lignocellulosic biomass into biofuel. The development of feedstocks with better biomass quality will improve conversion efficiency and the sustainability of the value-chain. Progress in the genetic improvement of biomass quality may be substantially expedited by the development of genetic markers associated to quality traits, which can be used in a marker-assisted selection program. RESULTS: To this end, a mapping population was developed by crossing two parents of contrasting cell wall composition. The performance of 182 F1 offspring individuals along with the parents was evaluated in a field trial with a randomized block design with three replicates. Plants were phenotyped for cell wall composition and conversion efficiency characters in the second and third growth season after establishment. A new SNP-based genetic map for M. sinensis was built using a genotyping-by-sequencing (GBS) approach, which resulted in 464 short-sequence uniparental markers that formed 16 linkage groups in the male map and 17 linkage groups in the female map. A total of 86 QTLs for a variety of biomass quality characteristics were identified, 20 of which were detected in both growth seasons. Twenty QTLs were directly associated to different conversion efficiency characters. Marker sequences were aligned to the sorghum reference genome to facilitate cross-species comparisons. Analyses revealed that for some traits previously identified QTLs in sorghum occurred in homologous regions on the same chromosome. CONCLUSION: In this work we report for the first time the genetic mapping of cell wall composition and bioconversion traits in the bioenergy crop miscanthus. These results are a first step towards the development of marker-assisted selection programs in miscanthus to improve biomass quality and facilitate its use as feedstock for biofuel production

Leishmaniose visceral (calazar) na Ilha de São Luís, Maranhão, Brasil: evolução e perspectivas

Leishmaniose visceral (calazar) entrou definitivamente como nosologia importante do Estado do Maranhão, Brasil, a partir de 1982. Desde então, vários autores têm trabalhado o tema do ponto de vista de relatos. No entanto, a parte de diagnóstico, tratamento e controle de cura percorreram caminhos difíceis e sempre preocupou os que estudam a doença que se instalou na Ilha de São Luís a partir da desestabilização dos ecótopos da Lutzomya longipalpis, o transmissor mais importante. Após 1993 a constatação de casos com má resposta ao antimoniato-n-metil glucamina (Glucantime®) veio se somar às outras preucupações. O estudo atual mostra como o Sistema Único de Saúde, através dos seus serviços, atua no controle da doença e conclui sobre a existência de refratariedade ao Glucantime® o que impõe maior vigilância no diagnóstico, tratamento e controle de cura dos pacientes.<br>Visceral leishmaniasis (kala-azar) was definitively an important disease of the state of Maranhão-Brasil since 1982. Since of then, many authors have been working with this topic in spite of reports. Nevertheless, the aspects of diagnosis, treatment an control of cure went through still hard worried the authors have been studing the disease, that came at São Luís Island since of the desestabilization of the ecotops of Lutzomya longipalpis, most important sandflies bites. After 1993 the constatation of cases with bad response to pentavalent antimonial (Glucantime®) comes to add the other worries. This actual trial accost the disease and conclude about an existence of failures to Glucantime® being important to have much vigilance in the diagnosis, treatment and control of cure of the patients