Caracterização de um isolado do Sugarcane mosaic virus que quebra a resistência de variedades comerciais de cana-de-açúcar

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Boron transport in Eucalyptus. 2. Identification in silico of a putative boron transporter for xylem loading in eucalypt

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Schistosoma mansoni: Evaluation of an RNAi-based treatment targeting HGPRTase gene

Hypoxanthine-guanine phosphoribosyltransferase (HGPRTase) is an essential gene of the parasite Schistosoma mansoni and it is well conserved in its hosts (mouse and human) at the protein but not at the RNA level. This feature prompted us to assess RNA interference (RNAi) to combat schistosomiasis. Small interfering RNAs (siRNAs) were Produced against HGPRTase, injected in infected mice and the number of worms was counted six days after injection. The total number of parasites was reduced by approximately 27% after treatment. RT-PCR analyzes showed a significant reduction in parasite target mRNA but not in host's homologue. The use of low doses of molecules did not oversaturate si- or miRNA pathways as mice survival rates were not affected by siRNAs. This is the first successful in vivo demonstration of a RNAi-based treatment against schistosomiasis. We believe that improvements in molecule delivery and an increase on siRNA dose could rapidly eliminate parasite. (c) 2007 Elsevier B.V. All rights reserved.

Genome-Wide Analysis of Differentially Expressed Genes During the Early Stages of Tomato Infection by a Potyvirus

Plant responses against pathogens cause up-and downward shifts in gene expression. To identify differentially expressed genes in a plant-virus interaction, susceptible tomato plants were inoculated with the potyvirus Pepper yellow mosaic virus (PepYMV) and a subtractive library was constructed from inoculated leaves at 72 h after inoculation. Several genes were identified as upregulated, including genes involved in plant defense responses (e. g., pathogenesis-related protein 5), regulation of the cell cycle (e. g., cytokinin-repressed proteins), signal transduction (e. g., CAX-interacting protein 4, SNF1 kinase), transcriptional regulators (e. g., WRKY and SCARECROW transcription factors), stress response proteins (e. g., Hsp90, DNA-J, 20S proteasome alpha subunit B, translationally controlled tumor protein), ubiquitins (e. g., polyubiquitin, ubiquitin activating enzyme 2), among others. Downregulated genes were also identified, which likewise display identity with genes involved in several metabolic pathways. Differential expression of selected genes was validated by macroarray analysis and quantitative real-time polymerase chain reaction. The possible roles played by some of these genes in the viral infection cycle are discussed.

The promoter of a gene encoding an isoflavone reductase-like protein in coffee (Coffea arabica) drives a stress-responsive expression in leaves

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The 20S proteasome alpha(5) subunit of Arabidopsis thaliana carries an RNase activity and interacts in planta with the Lettuce mosaic potyvirus HcPro protein

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Arabidopsis thaliana Uncoupling Proteins (AtUCPs): insights into gene expression during development and stress response and epigenetic regulation

Mitochondrial inner membrane uncoupling proteins (UCP) catalyze a proton conductance that dissipates the proton electrochemical gradient established by the respiratory chain, thus affecting the yield of ATP synthesis. UCPs are involved in mitochondrial energy flow regulation and have been implicated in oxidative stress tolerance. Based on the global gene expression profiling datasets available for Arabidopsis thaliana, in this review we discuss the regulation of UCP gene expression during development and in response to stress, and provide interesting insights on the possible existence of epigenetic regulation of UCP expression.

CaPrx, a Coffea arabica gene encoding a putative class III peroxidase induced by root-knot nematode infection

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Identification of suitable internal control genes for expression studies in Coffea arabica under different experimental conditions

Background: Quantitative data from gene expression experiments are often normalized by transcription levels of reference or housekeeping genes. An inherent assumption for their use is that the expression of these genes is highly uniform in living organisms during various phases of development, in different cell types and under diverse environmental conditions. To date, the validation of reference genes in plants has received very little attention and suitable reference genes have not been defined for a great number of crop species including Coffea arabica. The aim of the research reported herein was to compare the relative expression of a set of potential reference genes across different types of tissue/organ samples of coffee. We also validated the expression profiles of the selected reference genes at various stages of development and under a specific biotic stress.Results: The expression levels of five frequently used housekeeping genes (reference genes), namely alcohol dehydrogenase (adh), 14-3-3, polyubiquitin (poly), beta-actin (actin) and glyceraldehyde-3-phosphate dehydrogenase (gapdh) was assessed by quantitative real-time RT-PCR over a set of five tissue/organ samples (root, stem, leaf, flower, and fruits) of Coffea arabica plants. In addition to these commonly used internal controls, three other genes encoding a cysteine proteinase (cys), a caffeine synthase (ccs) and the 60S ribosomal protein L7 (rpl7) were also tested. Their stability and suitability as reference genes were validated by geNorm, NormFinder and BestKeeper programs. The obtained results revealed significantly variable expression levels of all reference genes analyzed, with the exception of gapdh, which showed no significant changes in expression among the investigated experimental conditions.Conclusion: Our data suggests that the expression of housekeeping genes is not completely stable in coffee. Based on our results, gapdh, followed by 14-3-3 and rpl7 were found to be homogeneously expressed and are therefore adequate for normalization purposes, showing equivalent transcript levels in different tissue/ organ samples. Gapdh is therefore the recommended reference gene for measuring gene expression in Coffea arabica. Its use will enable more accurate and reliable normalization of tissue/organ-specific gene expression studies in this important cherry crop plant.

An Arabidopsis Mitochondrial Uncoupling Protein Confers Tolerance to Drought and Salt Stress in Transgenic Tobacco Plants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Stochastic dynamics in exotic and native blowflies: an analysis combining laboratory experiments and a two-patch metapopulation model

In this study we explored the stochastic population dynamics of three exotic blowfly species, Chrysomya albiceps, Chrysomya megacephala and Chrysomya putoria, and two native species, Cochliomyia macellaria and Lucilia eximia, by combining a density-dependent growth model with a two-patch metapopulation model. Stochastic fecundity, survival and migration were investigated by permitting random variations between predetermined demographic boundary values based on experimental data. Lucilia eximia and Chrysomya albiceps were the species most susceptible to the risk of local extinction. Cochliomyia macellaria, C. megacephala and C. putoria exhibited lower risks of extinction when compared to the other species. The simultaneous analysis of stochastic fecundity and survival revealed an increase in the extinction risk for all species. When stochastic fecundity, survival and migration were simulated together, the coupled populations were synchronized in the five species. These results are discussed, emphasizing biological invasion and interspecific interaction dynamics.

Megaselia scalaris (Diptera : Phoridae) causing myiasis in Crotalus durissus terrificus (Serpentes : Viperidae) in Brazil

We describe a case of myiasis in Crotalus durissus terrificus (Laurenti) caused by Megaselia scalaris (Loew). The snake was Found in Anhembi, São Paulo, Brazil, with a lesion measuring 25 mm in diameter where the larvae of M. scalaris had penetrated the ribs. The opportunistic behavior of the larvae of M. scalaris is discussed.

Dispersal and predation behavior in larvae of Chrysomya albiceps and Chrysomya megacephala (Diptera : Calliphoridae)

Chrysomya albiceps and Chrysomya megacephala are exotic blowfly species known by producing myiasis in humans and other animals and by transmitting pathogens mechanically. C. albiceps stand out by being a facultative predator of other dipteran larvae. In this paper we investigated the influence of larval predation on the dispersal of larvae of C. albiceps and C. megacephala single and double species for three photophases. An experimental acrylic channel graduated and covered with wood shavings was used to observe the larval dispersal. The results showed that C. albiceps attacks C. megacephala larvae during dispersal and keeps an aggregated pattern close to the release point, in single and double species, independently of the different photophases. Chrysomya megacephala single species exhibited the same pattern, but in double species this was changed to a random distribution.

Fuzzy subset approach in coupled population dynamics of blowflies

This paper is a study on the population dynamics of blowflies employing a density-dependent. non-linear mathematical model and a coupled population formalism. In this Study, we investigated the coupled population dynamics applying fuzzy subsets to model the Population trajectory. analyzing demographic parameters such as fecundity, Survival, and migration. The main results suggest different possibilities in terms of dynamic behavior produced by migration in coupled Populations between distinct environments and the rescue effect generated by the connection between populations. It was possible to conclude that environmental heterogeneity can play an important role in blowfly metapopulation systems. The implications of these results for population dynamics of blowflies are discussed.