IQ - Instituto de Química
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O Instituto de Química, da Universidade Federal de Goiás, oferece os cursos de: Química e de Engenharia Química.
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Navegando IQ - Instituto de Química por Autor "Alcantara, Glaucia Braz"
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Item 1H HR-MAS NMR and S180 cells: metabolite assignment and evaluation of pulse sequence(2014-04) Oliveira, Aline Lima de; Martinelli, Bruno César Barbosa; Liao, Luciano Morais; Pereira, Flávia de Castro; Lacerda, Elisângela de Paula Silveira; Alcantara, Glaucia BrazHigh resolution magic angle spinning 1H nuclear magnetic resonance spectroscopy (HR-MAS NMR) is a useful technique for evaluation of intact cells and tissues. However, optimal NMR parameters are crucial in obtaining reliable results. To identify the key steps for the optimization of HR-MAS NMR parameters, we assessed different pulse sequences and NMR parameters using sarcoma 180 (S180) cells. A complete assignment of the metabolites of S180 is given to assist future studies.Item 1H HRMAS NMR spectroscopy and chemometrics for evaluation of metabolic changes in citrus sinensis caused by xanthomonas axonopodis pv. citri(2012-05) Silva, Lorena Mara Alexandre e; Alves Filho, Elenilson de Godoy; Choze, Rafael; Liao, Luciano Morais; Alcantara, Glaucia BrazXanthomonas axonopodis (Xac) bacterium causes one of the most feared and untreatable diseases in citriculture: citrus canker. To understand the response mechanisms of orange trees when attacked by Xac, leaves and fruits of Citrus sinensis were directly evaluated by HRMAS NMR (high resolution magic angle spinning nuclear magnetic resonance) spectroscopy. This technique allows the analysis of samples without laborious pre-treatments and also allows access to important information about chemical composition of samples. The orange tree leaves and fruit peels investigated in this study demonstrated the biochemical changes caused by Xac. Aided by chemometric analysis, the HRMAS NMR results show relevant changes in amino acids, carbohydrates, organic acids and terpenoids content.Item Decomposition dynamics of Typha angustifolia under aerobic conditions(2016-02-15) Oliveira, Caroline Silva de; Alcantara, Glaucia Braz; Liao, Luciano Morais; Mesquita, Glenda Máris; Freitas, Silvia de Sousa; Petacci, FernandoThe study of the Typha species has gained attention in tropical areas due to their rapid growth, nutrient release, and contribution to detritus in lakes. Analysis of the degradation of Typha angustifolia has shown that the first stage of decomposition is marked primarily by the release of soluble compounds, indicating that microorganisms have a minor influence at this stage. In subsequent stages, microorganisms act by degrading and consuming phenolic compounds and phosphorus. The remaining compounds form humic substances and are retained in the detritus. Thus, microorganisms significantly degrade organic matter, resulting in a two-fold increase in decomposition. Different forms of phosphorus could be detected in the remaining mass by 31P NMR (nuclear magnetic resonance). By comparing the 31P NMR data between the samples with and without the antibiotic, we can better understand the slow decomposition process of Typha angustifolia.Item Discrimination of sugarcane according to cultivar by ¹H NMR and chemometric analyses(2012-12) Alves Filho, Elenilson de Godoy; Silva, Lorena Mara Alexandre e; Choze, Rafael; Liao, Luciano Morais; Honda, Neli Kika; Alcantara, Glaucia BrazSeveral technologies for the development of new sugarcane cultivars have mainly focused on the increase in productivity and greater disease resistance. Sugarcane cultivars are usually identified by the organography of the leaves and stems, the analysis of peroxidase and esterase isoenzyme activities and the total soluble protein as well as soluble solid content. Nuclear magnetic resonance (NMR) associated with chemometric analysis has proven to be a valuable tool for cultivar assessment. Thus, this article describes the potential of chemometric analysis applied to 1H high resolution magic angle spinning (HRMAS) and NMR in solution for the investigation of sugarcane cultivars. For this purpose, leaves from eight different cultivars of sugarcane were investigated by 1H NMR spectroscopy in combination with chemometric analysis. The approach shows to be a useful tool for the distinction and classification of different sugarcane cultivars as well as to access the differences on its chemical composition.Item Fracionamento de polifosfato de sódio e caracterização por RMN de 31P: um experimento para aulas de físico-química(2010-08) Lima, Emília Celma de Oliveira; Alcantara, Glaucia Braz; Damasceno, Fernando Cruvinel; Moita Neto, José Machado; Galembeck, FernandoThis text describes an experiment on fractional precipitation of a polymer together with determination of average degree of polymerization by NMR. Commercial sodium polyphosphate was fractionated by precipitation from aqueous solution by adding increasing amounts of acetone. The polydisperse salt and nine fractions obtained from it were analyzed by 31P Nuclear Magnetic Resonance and the degree of polymerization of the salts and of the fractions were calculated. Long-chain sodium polyphosphate was also synthesized and analyzed. This experiment was tested in a PChem lab course but it can be used also to illustrate topics of inorganic polymers and analytical chemistry.Item HR-MAS NMR for rapid identification of illicit substances in tablets and blotter papers seized by police department(2016-04-06) Souza, Luciano Figueiredo de; Vieira, Tarcisio da Silva; Alcantara, Glaucia Braz; Liao, Luciano MoraisIllicit substances found in blotter papers and tablets seized by police are traditionally identified and characterized from extracts of these materials. However, the procedures involved in extraction stages can result in artifacts and even contamination of the samples to be analyzed. On the other hand, high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) is a technique that requires no pretreatment steps, enabling direct analysis of the material, including the analysis of new illegal synthetic psychoactive substances. This study presents and discusses applications of the HR-MAS NMR in the analysis of tablets and blotter papers seized. Additional analysis in solution of the extracts of these materials was performed to compare the obtained spectral resolution signals. The results demonstrated that the HR-MAS NMR allowed the rapid identification of 3,4-methylenedioxy-N-methylcathinone (methylone), 4-methylmethcathinone (mephedrone), 2,5-dimethoxy-4-bromoamphetamine (DOB) and 2-(4-bromo-2,5-dimethoxyphenyl)-N-[(2- methoxyphenyl)methyl]ethanamine (25B-NBOMe) in samples of tablets and blotter papers seized in Goiás State, Brazil.Item Metabolic response of soybean plants to Sclerotinia sclerotiorum infection(2019) Oliveira, Caroline Silva de; Liao, Luciano Morais; Alcantara, Glaucia BrazWhite mold is a disease caused by the fungus Sclerotinia sclerotiorum, a highly destructive necrotrophic pathogen that infects soybean crops, among others. Usually, the infection triggers the plant defense system to minimize the damages. However, the effects of the infection on soybean plant metabolism are still unclear. In this work, the metabolic profiles of soybean stems and leaves were accessed using 1H HR-MAS NMR spectroscopy to identify metabolic changes as a response to S. sclerotiorum infection. This fungus widely affects the central metabolism of soybean plants, and most of the altered metabolites are involved in carbon metabolism, as suggested by the results. Furthermore, the metabolites of central metabolism can be associated with the production of several polyphenolic metabolites. Changes in metabolic profile of leaves indicate systemic effects.Item NMR-based metabolomics of dried berries in comparison with dietary supplements(2022) Peçanha, Juliana de Souza; Santos, Nathalia Medina dos; Maróstica Junior, Mário Roberto; Micheletti, Ana Camila; Liao, Luciano Morais; Alcantara, Glaucia BrazConsumption of dried berries is increasing worldwide due to their health benefits. This popularity has introduced berry-based supplements as an easier way to take in berry nutrients. The chemical composition of six dried berries (blueberry, cranberry, goji berry, golden berry, maqui berry, and raspberry) were compared to their berry-based supplements by metabolomics using nuclear magnetic resonance spectroscopy (NMR). Thirty-three metabolites were identified and 23 were quantified. Chemometric analysis of berries revealed that goji berry showed the highest content of amino and organic acids, while cranberry and golden berry showed a high carbohydrate content. Fatty acids were predominant in blueberry, golden berry, maqui berry, and raspberry. Additionally, an exploratory analysis of phenolic compounds in berry extracts were conducted. phenolic compounds in berry extracts could be correlated with their antioxidant activity. Additionally, derived supplements did not show similarities with their respective berry, suggesting the minimal addition of dried berry in their formulation. Thus, non-declared additives have highlighted the importance of food safety investigation.Item NMR-based metabolomics of transgenic and non-transgenic sweet orange reveals different responses in primary metabolism during citrus canker development(2017) Apparecido, Rafael do Prado; Carlos, Eduardo Fermino; Liao, Luciano Morais; Vieira, Luiz Gonzaga Esteves; Alcantara, Glaucia BrazIntroduction Citrus canker, a disease caused by Xanthomonas axonopodis pv. citri (Xac) bacteria, has been responsible for extensive economic losses in citriculture. In this work, we report the metabolic responses of citrus plants during disease development. This information can be useful for understanding the natural mechanism of plant defense beyond helping design new varieties and/or genetically modified genotypes for tolerance/resistance against citrus canker. Objectives To understand how primary metabolism is affected in two sweet orange genotypes during citrus canker development. Methods 1H NMR spectroscopy together with chemometrics was used to evaluate the metabolic changes caused by Xac infection at various time points (days 4, 12 and 20) in Citrus sinensis L. Osbeck leaves from non-transgenic and transgenic plants expressing the antibacterial peptide sarcotoxin. Results The results revealed a high level of metabolic similarity between the studied genotypes without Xac infection. However, after Xac infection, the plants responded differently to disease development. The non-transgenic genotype showed altered early precursors of some secondary metabolites (tryptophan, tyrosine and putrescine) in addition to signaling metabolites of biotic stress (putrescine and dimethylamine), and the drastic reduction of gluconeogenesis was the overall metabolic cost for defense. The transgenic genotype suffered late metabolic changes due to the protective stoichiometric role of sarcotoxin. In addition, the oxidative stress response was more balanced in transgenic than in non-transgenic plants. Conclusion An NMR-based metabolomic approach was useful for understanding plant–pathogen interactions in citrus canker. Our findings provide valuable preliminary insights into different stages of citrus canker development.Item Qualitative and quantitative control of pediatric syrups using Nuclear Magnetic Resonance and chemometrics(2018) Alves Filho, Elenilson de Godoy; Silva, Lorena Mara Alexandre e; Araújo, Nathália Vitória Pereira; Liao, Luciano Morais; Alcantara, Glaucia BrazSeveral flavoring and sweetening agents added to excipient of pediatric syrups are not declared in the package leaflet. Therefore, the aim of this study was to develop a non-target, simple, and precise method for qualitative and quantitative evaluation of pediatric syrups using NMR spectroscopy combined with chemometrics. This approach allowed the identification of several added compounds as citric acid, cyclamate, ethanol, glycerol, propylene glycol, saccharin, sorbitol, fructose, glucose, and sucrose. Among the sugared syrups, sucrose was the main carbohydrate with approximately 59.1%, and for sweetened syrups, glycerol with 25.5%. The ethanol was found with highest concentration of 4.0%, approximately. In addition, some syrups presented both sugar and sweetener, which is inconsistent according to the purpose of the addition. Consequently, institutional structures of countries as Brazil that are in charge of public health should put additional compliance pressure on pharmaceutical companies to clearly declare in package leaflet the presence and exact amount of the main compounds (at least) existent in the pediatric excipients.