The main goal of this work is to evaluate some differential protein species in transgenic (T) and nontransgenic (NT) Arabidopsis thaliana plants after their cultivation in the presence or absence of sodium selenite. The transgenic line was obtained through insertion of CaMV 35S controlling nptII gene. Comparative proteomics through 2D-DIGE is carried out in four different groups (NT × T; NT × Se-NT (where Se is selenium); Se-NT × Se-T, and T × Se-T). Although no differential proteins are achieved in the T × Se-T group, for the others, 68 differential proteins (by applying a regulation factor ≥1.5) are achieved, and 27 of them accurately characterized by ESI-MS/MS. These proteins are classified into metabolism, energy, signal transduction, disease/defense categories, and some of them are involved in the glycolysis pathway-Photosystems I and II and ROS combat. Additionally, laser ablation imaging is used for evaluating the Se and sulfur distribution in leaves of different groups, corroborating some results obtained and related to proteins involved in the glycolysis pathway. From these results, it is possible to conclude that the genetic modification also confers to the plant resistance to oxidative stress.

High-level ab initio methods are used to analyze the electronic structure and vibrational spectra of the anthranilic acid or ortho-aminobenzoic acid (o-Abz), both in gas phase and aqueous solution. The geometries of the stationary points for the two lowest energy conformations (I and II) of o-Abz are optimized at the MP2/6-31þþG** and MP2/aug-cc-pVDZ levels of theory. Conformation I is found to be more stable, less polar but more polarizable than conformation II. The same levels of calculation are used to obtain the harmonic vibrational frequencies. Polarizable continuum model method is used later to study the solvent effect on the structure and vibrational spectra of o-Abz. Several electronic, electric, and thermodynamical properties are calculated and compared with the available experimental results and other theoretical calculations. The aqueous solution produces red-shift for most of the vibrational frequencies but increases the intensity of vibrations for all modes of vibration of o-Abz.

Arabidopsis thaliana is a small, owering plant that is widely used as a model organism in plant biology, mainly because it is the rst plant to have its entire genome sequenced. It has since proven to be an ideal organism for studying plant development. Arabidopsis is commonly used as a model plant for genomics, metabolomics and proteomics studies, and more recently it has been utilized in metallomic studies. Because of its widespread applications, many methods for Arabidopsis sample preparation, analytes separation and data quanti cation have been explored. is review brie y describes the Arabidopsis thaliana characteristics, the developed researches and the primary methods using this plant in di erent elds of OMICS. In the future, the availability of Arabidopsis genomic information may result in its continuous development for nanoparticles and metallomics studies.

viii ix "Confia no SENHOR de todo o teu coração, e não te estribes no teu próprio entendimento. Reconhece-o em todos os teus caminhos, e ele endireitará as tuas veredas. Não sejas sábio aos teus próprios olhos; tema ao SENHOR e aparta-te do mal. Isto será saúde para o teu âmago, e medula para os teus ossos." Provérbios de Salomão 3:5-8 "Porque nada há encoberto que não haja de ser manifesto; e nada se faz para ficar oculto, mas para ser descoberto." Evangelho de Marcos 4:22x xi AGRADECIMENTOS Sou grata ao SENHOR Altíssimo, por Ele ter sido sempre bom e justo. Sua palavra é viva e eficaz! Sou grata aos meus pais (Paulo e Edna), irmãos (Érika, Paulo Sérgio, Ana Paula e Fernanda), àqueles que se fizeram parte da minha família ("tio" Braulino, cunhada Elize e namorado Orlando), pelo apoio incondicional, pelo consolo com palavras de motivação e pela preocupação que revigoraram os meus dias, apesar do preço da distância. Sou grata ao meu orientador da Iniciação Científica (prof. Dr. Puspitapallab Chaudhuri) e sua esposa (profa. Dra. Angsula Ghosh), pela maneira que me incentivaram à pesquisa científica. Sou grata ao meu orientador de Mestrado (prof. Dr. Marco Aurélio Zezzi Arruda), pela oportunidade e confiança. Sou grata à CAPES, pela bolsa concedida, bem como a FAPESP e CNPq, por apoiarem financeiramente. Sou grata ao prof. Dr. Carlos Ramos e ao prof. Dr. Gonçalo Pereira e respectivos colaboradores, por terem cedido os lotes de sementes, a infraestrutura dos laboratórios de "Química de Proteínas" (Instituto de Química) e de "Genômica e Expressão" (Instituto de Biologia). E também ao professor Fábio Gozzo e colaboradores, pela infraestrutura do laboratório de espectrometria de massas "Dalton". Sou grata àqueles amigos da minha cidade natal (Manaus) e aos amigos de vários lugares do Brasil e do mundo que conheci na cidade de Campinas, que tiveram influências para a motivação deste trabalho. De maneira especial, sou muitíssimo grata: ao "Grupo de Espectrometria, Preparo de Amostra e xii