Análise e caracterização do gene de osmotina em cupuaçuzeiro.

O cupuaçuzeiro, Theobroma grandiflorum (Willd. ex Spreng.) Schum., pertence à família Malvaceae e é nativo da região Amazônica. A cultura do cupuaçuzeiro é afetada pela doença vassoura-de-bruxa, causada pelo fungo Moniliophthora perniciosa, provocando uma grande redução na produção de frutos. O conhecimento molecular da interação planta-patógeno é essencial para o desenvolvimento de ferramentas para o controle da doença, como por exemplo, a identificação de genótipos resistentes. Genes expressos em resposta ao ataque de patógenos são alvos de estudos desta interação. O objetivo do presente trabalho foi caracterizar um deles, o gene de osmotina, em cupuaçuzeiro. Sequências anotadas do transcriptoma de frutos de cupuaçuzeiro foram avaliadas quanto à presença deste gene. Os genes identificados foram comparados ao de osmotina de cacau pelo programa BLAST. Além disso, a organização do gene foi analisada por Southern blot, utilizando DNA genômico de cupuaçu. Identificaram-se duas sequências tipo osmotina: uma de 381 pb e outra de 477 pb, que correspondem a aproximadamente 63% e 79%, respectivamente, da região codificadora da proteína madura de cacau (607 pb). A comparação destas duas sequências com o gene de osmotina de cacau revelou identidade de cerca de 70%. Quanto à organização genômica em cupuaçu, foi observado que o gene está presente em múltiplas cópias. Estudos posteriores são necessários para investigar o envolvimento deste gene com os fenótipos de resistência à vassoura-de-bruxa

Identificação e análise de genes expressos em semente e polpa de cupuaçuzeiro.

O cupuaçuzeiro, Theobroma grandiflorum (Willd. ex Spreng.) Schumm., é a segunda espécie mais importante para a fruticultura da região amazônica, com cerca de 10% do mercado de todas as frutas amazônicas. Apesar de sua importância econômica, pouco se conhece sobre a base genética desta planta, em particular, as bases moleculares. Este trabalho teve como objetivo identificar genes expressos em frutos de cupuaçuzeiro, para disponibilizar uma nova ferramenta de apoio aos trabalhos de melhoramento genético. RNA dos frutos foram obtidos e, após processamento, as sequências foram determinadas por pirosequenciamento, utilizando-se a plataforma 454 (Roche Applied Science). Para os processos de limpeza das sequências e obtenção dos contigs, foram utilizados os programas est2assembly e mira assembly. A busca por similaridade foi realizada utilizando o programa BLASTX contra o banco de dados de proteínas NR (não-redundante). Cerca de 6.200 contigs apresentaram similaridade com proteínas previamente descritas. Em seguida, foram selecionados alguns contigs com potencial para utilização nos programas de melhoramento vegetal. Dentre eles, 20 foram similares a proteínas descritas para o gênero Theobroma e 6 para outros gêneros. As sequências selecionadas são relacionadas a genes codificadores de proteínas de reserva, de resposta a estresse, da via de síntese de ácidos graxos, etc. Análises mais aprofundadas das sequências permitirão a construção de uma importante base de dados moleculares para esta cultura

Genomic analysis in the study of drought tolerance using recombinant inbred lines and recurrent selection.

Plant breeding for drought tolerance is one of the approaches that can be applied in order to improve water use efficiency in agriculture

Experimental Signature of Medium Modifications for rho and omega Mesons in the 12 GeV p + A Reactions

The invariant mass spectra of e+e- pairs produced in 12-GeV proton-induced nuclear reactions are measured at the KEK Proton-Synchrotron. On the low-mass side of the omega meson peak, a significant enhancement over the known hadronic sources has been observed. The mass spectra, including the excess, are well reproduced by a model that takes into account the density dependence of the vector meson mass modification, as theoretically predicted.Comment: 4 pages, 3 figures, Version accepted for Physical Review Lette

Overexpression of grappa encoding a histone methyltransferase enhances stress resistance in Drosophila

Histone deacetylases, such as silent information regulator 2 (Sir2) and Rpd3 are involved in chromatin silencing and implicated in lifespan determination in several organisms. The yeast Dot1 gene encoding a histone methyltransferase affects localization of silencing proteins including Sir2, and plays an essential role in the repair of damaged DNA. However, it is not known whether an alteration of a histone methyltransferase activity influences lifespan or stress resistance, which is often associated with extended lifespan. Here we investigated whether the Drosophilagrappa (gpp) gene, a Dot1 homolog influences lifespan and stress resistance using transgenic flies overexpressing gpp and those bearing a partial loss-of-function mutation. Overexpression of gpp throughout the adult stage did not extend the lifespan, but significantly enhanced resistances when they were kept on medium containing 1% H(2)O(2), or those with poor nutrients. As well, gpp-overexpressing flies were behaviourally more active than control flies. We investigated whether gpp overexpression induced anti-oxidant genes, Catalase, Sod, Sod2, GstD2, dhd, TrxT and Trx-2. However, none of these genes was induced. A partial loss-of-function mutations in gpp dramatically reduced the lifespan under oxidative and caloric stresses. Taken together, these results demonstrated that gpp is required for normal lifespan and stress resistance, and that its overexpression increases stress resistance in Drosophila, without obvious induction of representative anti-oxidant genes

Lyso-GM2 Ganglioside: A Possible Biomarker of Tay-Sachs Disease and Sandhoff Disease

To find a new biomarker of Tay-Sachs disease and Sandhoff disease. The lyso-GM2 ganglioside (lyso-GM2) levels in the brain and plasma in Sandhoff mice were measured by means of high performance liquid chromatography and the effect of a modified hexosaminidase (Hex) B exhibiting Hex A-like activity was examined. Then, the lyso-GM2 concentrations in human plasma samples were determined. The lyso-GM2 levels in the brain and plasma in Sandhoff mice were apparently increased compared with those in wild-type mice, and they decreased on intracerebroventricular administration of the modified Hex B. The lyso-GM2 levels in plasma of patients with Tay-Sachs disease and Sandhoff disease were increased, and the increase in lyso-GM2 was associated with a decrease in Hex A activity. Lyso-GM2 is expected to be a potential biomarker of Tay-Sachs disease and Sandhoff disease

Analysis of the leaf transcriptome of Musa acuminata during interaction with Mycosphaerella musicola: gene assembly, annotation and marker development.

Background: Although banana (Musa sp.) is an important edible crop, contributing towards poverty alleviation and food security, limited transcriptome datasets are available for use in accelerated molecular-based breeding in this genus. 454 GS-FLX Titanium technology was employed to determine the sequence of gene transcripts in genotypes of Musa acuminata ssp. burmannicoides Calcutta 4 and M. acuminata subgroup Cavendish cv. Grande Naine, contrasting in resistance to the fungal pathogen Mycosphaerella musicola, causal organism of Sigatoka leaf spot disease. To enrich for transcripts under biotic stress responses, full length-enriched cDNA libraries were prepared from whole plant leaf materials, both uninfected and artificially challenged with pathogen conidiospores. Results: The study generated 846,762 high quality sequence reads, with an average length of 334 bp and totaling 283 Mbp. De novo assembly generated 36,384 and 35,269 unigene sequences for M. acuminata Calcutta 4 and Cavendish Grande Naine, respectively. A total of 64.4% of the unigenes were annotated through Basic Local Alignment Search Tool (BLAST) similarity analyses against public databases. Assembled sequences were functionally mapped to Gene Ontology (GO) terms, with unigene functions covering a diverse range of molecular functions, biological processes and cellular components. Genes from a number of defense-related pathways were observed in transcripts from each cDNA library. Over 99% of contig unigenes mapped to exon regions in the reference M. acuminata DH Pahang whole genome sequence. A total of 4068 genic-SSR loci were identified in Calcutta 4 and 4095 in Cavendish Grande Naine. A subset of 95 potential defense-related gene-derived simple sequence repeat (SSR) loci were validated for specific amplification and polymorphism across M. acuminata accessions. Fourteen loci were polymorphic, with alleles per polymorphic locus ranging from 3 to 8 and polymorphism information content ranging from 0.34 to 0.82. Conclusions: A large set of unigenes were characterized in this study for both M. acuminata Calcutta 4 and Cavendish Grande Naine, increasing the number of public domain Musa ESTs. This transcriptome is an invaluable resource for furthering our understanding of biological processes elicited during biotic stresses in Musa. Gene-based markers will facilitate molecular breeding strategies, forming the basis of genetic linkage mapping and analysis of quantitative trait loci