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Estudo computacional da enzima gGAPDH do Trypanosoma cruzi
(Universidade Federal de São Carlos, 2009-06-05) Oliveira, Osmair Vital de; Freitas, Luiz Carlos Gomide; https://lattes.cnpq.br/3461414255262928; https://lattes.cnpq.br/3019137922691272
Theoretical methods in computational chemistry were used to study the gGAPDH enzyme from Trypanosoma cruzi. This protozoan is responsible by the Chagas diseases. Molecular dynamics simulations were performed to obtain the time evolution of the gGAPDH enzyme in the holo (with the cofactor NAD+) and apo (without the cofactor) forms in aqueous solution. The calculations were performed in the NpT ensemble with T = 300K e p = 1bar. In these simulations little conformational changes were observed in both holo and apo forms of the enzyme along 20.0 ns simulation time. Docking calculations were carried out to fit some drugs in enzyme active site using the ensemble docking methodology. Therefore, multiple enzyme conformations of both holo and apo forms were obtained at time intervals of 2.0 ns along the molecular dynamics simulation. This procedure was used to take in into account the flexibility of the enzyme. The results from these calculations indicate that the best way to develop a drug molecule is to consider both enzyme forms (holo and apo forms). In this way, one drug will inhibit the apo form and other, the holo form. To characterize the enzymatic mechanism, the glyceraldehyde 3-phosphate (G3P) was placed in the active site (via docking calculations) of the holo form conformation obtained in the end of the 20.0 ns trajectory. A 1.0 ns molecular dynamic simulation was performed in the (gGAPDH-NAD+-G3P) system. Quantum chemical calculations were performed to study reactive process in the enzyme catalytic site. A convenient model was built using about 698 atoms carefully chosen to represent the active site and its surroundings. The calculations were performed using a combination of MOZYME and the usual SCF procedure implemented in the MOPAC2009 program. The calculations were performed at the PM6 level. One of the reaction mechanisms proposed in the literature was characterized xix calculating the energy profile along the reaction path to transfer a proton from Cys166 to His194. Using a second structure obtained from molecular dynamics, a new mechanism for the gGAPDH enzyme was proposed and characterized by a similar MOPAC2009 calculation. In this mechanism, the hydroxyl group of the G3P acts as a bridge to transfer the proton from the Cys166 to His194 residue.
Relações entre o tipo psicológico e a aprendizagem de uma língua estrangeira
(Universidade Federal de São Carlos, 2009-06-05) Belonsi, Lileni Marileili Drugovich; Silva, Ademar da; https://lattes.cnpq.br/9028512631572133; https://lattes.cnpq.br/4917585425367055
There are several factors which interfere in foreign language learning. Among them, there are the learning styles, which comprise the cognitive and affective domains. The intrinsic side of the affective domain, which is the personality, should be considered as an important factor on the building of a foreign language teaching/learning theory, because it gives priority to human behavior concerning the way people learn. Although Personality Traits or Psychological Types may be regarded as circumstantial, that is, without reliability or strength, they may be indicators of personal needs during a certain moment. The purpose of this study was to investigate whether the learner s Psychological Type is reflected on the way he processes information, on his motivation and on the way he develops strategies which help him to deal with the most different learning situations. Knowing the different Psychological Types (such as extroverted, perceptive, judger, intuitive) as well as their characteristics, may be quite important for the teacher, because, through this knowledge, he will be able to better identify the difficulties of a determined learner or a group of learners and provide them with means to reduce them; in relation to the learner, one will have conditions to search more autonomy when learning a foreign language, because one will know how to satisfy his preferences and how to deal with his learning difficulties. By having as theoretical base the studies developed by the psychiatrist Carl Jung in the 1920s, which were further revised and improved by Myers and Briggs (1987; 1995; 1997) and having as reference the studies developed by Ehrman (1996), we pointed out some personality differences which are relevant to the learning process. We analyzed and interpreted the data, which were collected from the answers given at the MBTI (Myers Briggs Type Indicator). The MBTI is an inventory developed by Myers and Briggs, which indicates the Psychological Type, classified into four bipolar or dichotomic dimensions according to the learner s preferences. Such data showed the traits of each Type, the relationship between the orientations and the abilities of each learner and the factors which contribute or not to the success in a foreign language (English) learning context.
Exposições ao alumínio em meio ácido afetam as brânquias e a osmorregulação do peixe neotropical Prochilodus lineatus
(Universidade Federal de São Carlos, 2009-06-05) Camargo, Marina Mori Pires de; Fernandes, Marisa Narciso; https://lattes.cnpq.br/3021357484136942; https://lattes.cnpq.br/3442998290367091
Aluminium is very toxic to fish. Biomarkers have been using to indicate water contamination, however, there are few studies concerning tropical fish species. So, the neotropical fish Prochilodus lineatus, were exposed to aproximately 200 μg.L-1 of dissolved Al em acid pH (Al group), only to acid water (pH group) or to water with pH 7.0 (CTR group) for 6, 24, 96h and 10 days to evaluate its effects on haematological, osmo-ionic, metabolic and endocrine parameters besides morphological analysis by light and electronic microscopy. Fishes exposed to Al have all haematological and metabolic parameters increased when compared to CTR group. Osmo-ionic parameters were significantly smaller in fishes exposed to Al as much as the Na+/K+-ATPase enzyme and the CC number smaller Light microscopy reveal that fish exposed to Al in all experimental periods showed lesions widely distributed in the tissue and considered more severe when compared to fish from other groups. In the Al group, the main alterations found were hyperplasia of the epithelial cells, lamellar fusion and hypertrophy of mucous cells. In the animals of pH group, the main alteration was hipertrophy of epithelial cells, especially of the CC. Scanning electron microscopy allowed to see great disorganization in the lamellae of the fishes exposed to Al, detachment of branchial epithelium and reduction of the interlamellar space. Chloride cells with sponge aspect were noted in the pH and Al groups, besides alteration in the microcript of the pv in both groups. Transmission electron microscopy showed that animals from Al group have more CC displaced to the tip of the lamellae and that these CC have a less dense cytoplasm, with a smaller quantity of tubules and mitochondrias and nuclei with altered shapes. The thickness of the lamellae is bigger because of the swollen pv and the interlamellar spaces are reduced. There are, also, more vacuoles in the cytoplasm of these CC. Results allowed to conclude that exposure to Al in acid medium impairs mostly the hyperegulation capacity of the fish, since it affects the active uptake of ions in the gills and also caused serious structural alterations in the organ, leading to functional problems, jeopardizing the survival of the fishes in such situation.
O discurso político e o tema corrupção: construções discursivo-ideológicas na relação entre a vida pública e a vida privada
(Universidade Federal de São Carlos, 2009-06-05) Silva, Michele Viana da; Miotello, Valdemir; https://lattes.cnpq.br/9131819326282708; https://lattes.cnpq.br/0001111917983214
This dissertation has as its investigation object the political speech of the Senator Renan Calheiros (who, at the moment, occupied the Presidency function), more precisely, his speech at the Federal Senate after a corruption denunciation by Veja Magazine, in May/2007. This paper aimed to comprehend how the discursive speaker defends himself from that accusation in order to verify the relation that is built among the speaker, his interlocutors and the discursive object. Before such problem questions, the dissertation follows a theoretical and methodological way based on Bakhtin s concepts concerning the discursive ideological relation as the essential element to comprehend the senses of words and the verbal interaction as the essence of the man (the dialogical principal). The study observed the presence of a confrontation between public life and private life which functions as a way to rebuild the discursive object. In the speech of Renan Calheiros, it is not his self-defense which occupies a central role, but values related to privacy and the institution, the Senate.
Desenvolvimento de descritores de imagens para reconhecimento de padrões de plantas invasoras (folhas largas e folhas estreitas)
(Universidade Federal de São Carlos, 2009-06-05) Santos, Ana Paula de Oliveira; Cruvinel, Paulo Estevão; https://lattes.cnpq.br/7924553462118511; https://lattes.cnpq.br/2368219284471351
In Brazil, the development of tools for weeds recognition, capable of aiding risk detection and decision making on the fieldwork is still embryonic. This master s thesis presents the development of a pattern recognition system that recognizes weeds and gives the occupation percentage of wide and narrow leaves in an agricultural production system, with digital image processing techniques. The development was based on considerations about image acquisition, pre-processing, texture based segmentation, descriptors for weeds recognition and occupation percentage of each kind of leaf. The validation has been developed considering geometric patterns generated in laboratory, as well as others obtained of a maize (Zea mays) production agricultural environment, i. e. two species of weeds, one with wide leaves (Euphorbia heterophylla L.) and other with narrow leaves (Digitaria sanguinalis Scop.). The results show recognition of about 84.24 percent for wide leaves and 80.17 percent for narrow leaves in agricultural environment and also the capability to spot weed on unreachable locations by natural vision. Besides, the method presents application in precision agriculture to improve the decision making in pulverization processes.