Diuron exposure induces systemic and organ-specific toxicity following acute and sub-chronic exposure in male Wistar rats

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

CDHI promoter hypermethylation and E-cadherin protein expression in infiltrating breast cancer

Background: the E-cadherin gene (CDH1) maps, at chromosome 16q22.1, a region often associated with loss of heterozygosity (LOH) in human breast cancer. LOH at this site is thought to lead to loss of function of this tumor suppressor gene and was correlated with decreased disease-free survival, poor prognosis, and metastasis. Differential CpG island methylation in the promoter region of the CDH1 gene might be an alternative way for the loss of expression and function of E-cadherin, leading to loss of tissue integrity, an essential step in tumor progression.Methods: the aim of our study was to assess, by Methylation-Specific Polymerase Chain Reaction (MSP), the methylation pattern of the CDH1 gene and its possible correlation with the expression of E-cadherin and other standard immunohistochemical parameters (Her-2, ER, PgR, p53, and K-67) in a series of 79 primary breast cancers ( 71 infiltrating ductal, 5 infiltrating lobular, 1 metaplastic, 1 apocrine, and 1 papillary carcinoma).Results: CDH1 hypermethylation was observed in 72% of the cases including 52/71 ductal, 4/5 lobular carcinomas and 1 apocrine carcinoma. Reduced levels of E-cadherin protein were observed in 85% of our samples. Although not statistically significant, the levels of E-cadherin expression tended to diminish with the CDH1 promoter region methylation. In the group of 71 ductal cancinomas, most of the cases of showing CDH1 hypermethylation also presented reduced levels of expression of ER and PgR proteins, and a possible association was observed between CDH1 methylation and ER expression ( p = 0.0301, Fisher's exact test). However, this finding was not considered significant after Bonferroni correction of p-value.Conclusion: Our preliminary findings suggested that abnormal CDH1 methylation occurs in high frequencies in infiltrating breast cancers associated with a decrease in E-cadherin expression in a subgroup of cases characterized by loss of expression of other important genes to the mammary carcinogenesis process, probably due to the disruption of the mechanism of maintenance of DNA methylation in tumoral cells.

Using Amino Acid Correlation and Community Detection Algorithms to Identify Functional Determinants in Protein Families

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

Mutational analysis of Arabidopsis thaliana plant uncoupling mitochondrial protein

In this study, point mutations were introduced in plant uncoupling mitochondrial protein AtUCP1, a typical member of the plant uncoupling protein (UCP) gene subfamily, in amino acid residues Lys147, Arg155 and Tyr269, located inside the so-called UCP-signatures, and in two more residues, Cys28 and His83, specific for plant UCPs. The effects of amino acid replacements on AtUCP1 biochemical properties were examined using reconstituted proteoliposomes. Residue Arg155 appears to be crucial for AtUCP1 affinity to linoleic acid (LA) whereas His83 plays an important role in AtUCP1 transport activity. Residues Cys28, Lys147, and also Tyr269 are probably essential for correct protein function, as their substitutions affected either the AtUCP1 affinity to LA and its transport activity, or sensitivity to inhibitors (purine nucleotides). Interestingly, Cys28 substitution reduced ATP inhibitory effect on AtUCP1, while Tyr269Phe mutant exhibited 2.8-fold increase in sensitivity to ATP, in accordance with the reverse mutation Phe267Tyr of mammalian UCP1. (C) 2007 Elsevier B.V. All fights reserved.

Screening and characterization of sex-specific DNA fragments in the freshwater fish matrinch, Brycon amazonicus (Teleostei: Characiformes: Characidae)

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

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)

Plasmodium falciparum: sequence diversity and antibody recognition of the Merozoite surface protein-2 (MSP-2) in Brazilian Amazonia

The merozoite surface protein-2 (MSP-2) of Plasmodium falciparum comprises repeats flanked by dimorphic domains defining the allelic families FC27 and IC1. Here, we examined sequence diversity at the msp-2 locus in Brazil and its impact on MSP-2 antibody recognition by local patients. Only 25 unique partial sequences of msp-2 were found in 61 isolates examined. The finding of identical msp-2 sequences in unrelated parasites, collected 6-13 years apart, suggests that no major directional selection is exerted by variant-specific immunity in this malaria-endemic area. To examine antibody cross-reactivity, recombinant polypeptides derived from locally prevalent and foreign MSP-2 variants were used in ELISA. Foreign IC1-type variants, such as 3D7 (currently tested for human vaccination), were less frequently recognized than FC27-type and local IC1-type variants. Antibodies discriminated between local and foreign IC1-type variants, but cross-recognized structurally different local IC1-type variants. The use of evolutionary models of MSP-2 is suggested to design vaccines that minimize differences between local parasites and vaccine antigens. (C) 2004 Elsevier B.V. All rights reserved.

Molecular models of protein targets from Mycobacterium tuberculosis

Structural characterization of enzymes that belong to microbial metabolic pathways is very important for structure-based drug design since some of these proteins may be present in the bacterial genome, but absent in humans. Thus, metabolic pathways became potential targets for drug design. The motivation of this work is the fact that Mycobacterium tuberculosis is the cause of the deaths of millions of people in the world, so that the structural characterization of protein targets to propose new drugs has become essential. DBMODELING is a relational database, created to highlight the importance of methods of molecular modeling applied to the Mycobacterium tuberculosis genome with the aim of proposing protein-ligand docking analysis. There are currently more than 300 models for proteins from Mycobacterium tuberculosis genome in the database. The database contains a detailed description of the reaction catalyzed by each enzyme and their atomic coordinates. Information about structures, a tool for animated gif image, a table with a specification of the metabolic pathway, modeled protein, inputs used in modeling, and analysis methods used in this project are available in the database for download. The search tool can be used for reseachers to find specific pathways or enzymes.

Identification of Rv3852 as a nucleoid-associated protein in Mycobacterium tuberculosis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Histochemistry and Protein Profile of The Venom Glands of Workers of Neoponera villosa Ants (Hymenoptera: Ponerinae)

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

Genetic diversity of NS5A protein from hepatitis C virus genotype 3a and its relationship to therapy response

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

Coordinate and time-dependent diffusion dynamics in protein folding

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Subcellular localization of the coat protein in tobacco cells infected by cucumber mosaic virus isolated from Catharanthus roseus

Electron microscopy and immunolabelling with antiserum specific to cucumber mosaic virus coat protein were used to examine tobacco leaf cells infected by cucumber mosaic virus isolated from Catharanthus roseus (CMV-Cr). Crystalline and amorphous inclusions in the vacuoles were the most obvious cytological modifications seen. Immunogold labelling indicated that the crystalline inclusion was made up of virus particles and amorphous inclusions contained coat protein. Rows of CMV-Cr particles were found between membranes of dictyosomes, but membranous bodies and tonoplast-associated vesicles were not evident. Virus particles and/or free coat protein were easily detected in the cytoplasm by immunolabelling. No gold labelling was found within nuclei, chloroplasts and mitochondria.

PR gene families of citrus: their organ specific-biotic and abiotic inducible expression profiles based on ESTs approach

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)