The Role of Cytoplasmic mRNA Cap-Binding Protein Complexes in Trypanosoma brucei and Other Trypanosomatids.

Trypanosomatid protozoa are unusual eukaryotes that are well known for having unusual ways of controlling their gene expression. The lack of a refined mode of transcriptional control in these organisms is compensated by several post-transcriptional control mechanisms, such as control of mRNA turnover and selection of mRNA for translation, that may modulate protein synthesis in response to several environmental conditions found in different hosts. In other eukaryotes, selection of mRNA for translation is mediated by the complex eIF4F, a heterotrimeric protein complex composed by the subunits eIF4E, eIF4G, and eIF4A, where the eIF4E binds to the 5'-cap structure of mature mRNAs. In this review, we present and discuss the characteristics of six trypanosomatid eIF4E homologs and their associated proteins that form multiple eIF4F complexes. The existence of multiple eIF4F complexes in trypanosomatids evokes exquisite mechanisms for differential mRNA recognition for translation

Nodulation, gas exchanges and production of peanut cultivated with Bradyrhizobium in soils with different textures.

Nitrogen fertilization from biological source is an uncommon practice for peanut growers due to the limited results, mainly in environments with water restriction. In this study, the response of a commercial Bradyrhizobium was evaluated on the nodulation and production of peanuts grown in sandy and medium textured soils. Two experiments using different soils were carried out in the field during the dry season, in Campina Grande, Paraíba State, Brazil. Three peanut genotypes were submitted to the following treatments: 1-no nitrogen fertilization (control), 2- chemical fertilization (ammonium sulfate) and 3- inoculation with Bradyrhizobium [commercial strain BR 1405 (SEMIA 6144)]. A completely randomized 3x3 factorial design was adopted with five repetitions for both experiments. The evaluates variables were: height of the main stem, number of nodes/plant, root length, root dry weight, weight of pods/plant and number of pods/plant. In addition, gas exchanges were estimated using IRGA apparatus. Both genotypes (BRS Havana and L7 Bege) were benefited in relation to production due to an inoculation with SEMIA 6144. No physiological response was verified in genotypes or N-treatments to gas exchange, excepting for the Ci/Ca ratio in the medium textured soil experiment. BRS Havana showed low Ci/Ca ratio in Bradyrhizobium treatment, indicating that SEMIA 6144 improved the plants photosynthetic efficiency

New triple systems in the RasTyc sample of stellar X-ray sources

During the study of a large set of late-type stellar X-ray sources, we discovered a large fraction of multiple systems. In this paper we investigate the orbital elements and kinematic properties of three new spectroscopic triple systems as well as spectral types and astrophysical parameters (T_eff, log g, vsin i, log N(Li)) of their components. We conducted follow-up optical observations, both photometric and spectroscopic at high resolution, of these systems. We used a synthetic approach and the cross-correlation method to derive most of the stellar parameters. We estimated reliable radial velocities and deduced the orbital elements of the inner binaries. The comparison of the observed spectra with synthetic composite ones, obtained as the weighted sum of three spectra of non-active reference stars, allowed us to determine the stellar parameters for each component of these systems. We found all are only composed of main sequence stars. These three systems are certainly stable hierarchical triples composed of short-period inner binaries plus a tertiary component in a long-period orbit. From their kinematics and/or Lithium content, these systems result to be fairly young.Comment: Accepted for publication in A&A (on July 22, 2008

Desempenho de linhagens de feijão-caupi com grãos de tegumento branco rugoso extra grandes sob cultivo irrigado.

Este trabalho teve por objetivo verificar o desempenho produtivo de 19 genótipos de feijão-caupi em cultivo irrigado nas condições edafoclimatológicas de Teresina-PI. O experimento foi conduzido sob irrigação por aspersão convencional, na Embrapa Meio-Norte, em Teresina, Piauí, nos anos 2008/2009. Foram realizados três ensaios utilizando-se delineamento de blocos casualizados com quatro repetições e 19 tratamentos, onde avaliou-se a produtividade de grãos. Utilizou-se a análise de variância univariada para aferir as respostas dos genótipos aos diferentes ambientes de cultivo e o teste Scott-Knott para comparação das médias. Foi observada resposta diferenciada dos genótipos nos ambientes. Na análise conjunta foi detectada diferença entre ambientes e a interação genótipo x ambiente foi significativa. Os melhores genótipos foram MNC05-828C-1-11, BRS Novaera, MNC05-829C-1-8 e MNC05-828C-30-11, todos com produtividade média superior a 1.400 kg.ha-1, podendo chegar 1.800 kg.ha-1. O melhor ambiente foi Teresina 2009 com produtividade de grãos média de 1.572,59 kg.ha-1.CONAC 2012. Disponível em: http://www.conac2012.org/resumos/pdf/182b.pdf. Acesso em: 05 ago. 2013