RESUMEN
In this work, a begomovirus isolated from a bean plant coinfected with the potyviruses bean common mosaic virus and bean common mosaic necrosis virus was characterized. The three viruses were detected by high-throughput sequencing and assembly of total small RNAs, but the begomovirus-related contigs did not allow precise identification. Molecular analysis based on standard DNA amplification techniques revealed the presence of a single bipartite virus, which is a novel begomovirus according to the current taxonomic criteria. Infectious clones were generated and agroinoculated into Phaseolus vulgaris and Nicotiana benthamiana plants. In all cases, viral DNA-A and DNA-B were detected in new growths, but no symptoms were observed, thus indicating that this virus produces asymptomatic infections in both host species.
Asunto(s)
Begomovirus/aislamiento & purificación , Nicotiana/virología , Phaseolus/virología , Enfermedades de las Plantas/virología , Potyvirus/fisiología , Begomovirus/clasificación , Begomovirus/genética , Begomovirus/fisiología , Coinfección/virologíaRESUMEN
The begomoviruses (BGVs) are plant pathogens that evolved in the Old World during the Cretaceous and arrived to the New World (NW) in the Cenozoic era. A subgroup of NW BGVs, the "Squash leaf curl virus (SLCV) lineage" (S-Lin), includes viruses with unique characteristics. To get clues on the evolutionary origin of this lineage, a search for divergent members was undertaken. Four novel BGVs were characterized, including one that is basal to the group. Comparative analyses led to discover a ~670 bp genome module that is nearly exclusive of this lineage, encompassing the replication origin, the AC4 gene, and 480 bp of the Rep gene. A similar DNA module was found in two curtoviruses, hence suggesting that the S-Lin ancestor acquired its distinctive genomic segment by recombination with a curtovirus. This hypothesis was definitely disproved by an in-depth sequence analysis. The search for homologs of S-Lin Rep uncover the common origin of Rep proteins encoded by diverse Geminiviridae genera and viral "fossils" integrated at plant genomes. In contrast, no homolog of S-Lin Rep was found in public databases. Consequently, it was concluded that the SLCV clade ancestor evolved by a recombination event between a primitive NW BGV and a virus from a hitherto unknown lineage.
Asunto(s)
Begomovirus/clasificación , Evolución Molecular , Geminiviridae/clasificación , Enfermedades de las Plantas/virología , Origen de Réplica , ADN Viral/genética , Genoma Viral , Filogenia , Recombinación Genética , Nicotiana/virología , Proteínas Virales/genética , Replicación Viral/genéticaRESUMEN
Objetivo: Determinar la relación entre la suplementación con sulfato ferroso y el rendimiento escolar. Metodología: estudio comparativo experimental. Durante el ciclo escolar se realizó suplementación diaria, de lunes a viernes, con 60 mg. de sulfato ferroso a 217 alumnas y otro grupo de 115 alumnas y otro grupo de 115 alumnas no lo recibió, por lo que se constituyó como grupo control. En todas las alumnas se midieron niveles de Hb y Ferritina sérica al inicio y al final del estudio, así como notas académicas. Resultados: se demostró que no existió relación entre mejora de anemia y rendimiento académico. Las niñas con anemia que fueron suplementadas, a pesar de continuar con niveles bajos de Hb y Ferritina, aprobaron el ciclo escolar en un porcentaje mayor (91/100), en comparación del grupo de niñas con anemia que no recibieron suplementación (20/100). Conclusiones: El estudio mostró que niñas con anemia que no recibieron suplementación, reprobaron en mayor porcentaje que las que si lo recibieron (p <0.01), pero esta mejora del rendimiento académico fue independiente del incremento en los niveles de Hb y Ferritina