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URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
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Item Functional complementation of a yeast knockout strain by Schistosoma mansoni Rho1 GTPase in the presence of caffeine, an agent that affects mutants defective in the protein kinase C signal transduction pathway(Instituto Oswaldo Cruz, Ministério da Saúde, 2006-05-26) Aguiar, Pedro H. N. de; Santos, Débora N.; Lobo, Francisco P.; Santos, Túlio M.; Macedo, Andréa M.; Pena, Sérgio D. J.; Machado, Carlos R.; Franco, Glória R.In a previous study, the Schistosoma mansoni Rho1 protein was able to complement Rho1 null mutant Saccharomyces cerevisiae cells at restrictive temperatures and under osmotic stress (low calcium concentration) better than the human homologue (RhoA). It is known that under osmotic stress, the S. cerevisiae Rho1 triggers two distinct pathways: activation of the membrane 1,3-beta-glucan synthase enzymatic complex and activation of the protein kinase C1 signal transduction pathway, promoting the transcription of response genes. In the present work the SmRho1 protein and its mutants smrho1E97P, smrho1L101T, and smrho1E97P, L101T were used to try to clarify the basis for the differential complementation of Rho1 knockout yeast strain by the human and S. mansoni genes. Experiments of functional complementation in the presence of caffeine and in the presence of the osmotic regulator sorbitol were conducted. SmRho1 and its mutants showed a differential complementation of the yeast cells in the presence of caffeine, since smrho1E97P and smrho1E97P, L101T mutants showed a delay in the growth when compared to the yeast complemented with the wild type SmRho1. However, in the presence of sorbitol and caffeine the wild type SmRho1 and mutants showed a similar complementation phenotype, as they allowed yeast growth in all caffeine concentrations tested.Item Café com quimioterapia: uma aplicação do planejamento fatorial fracionário 2|5-1(Sociedade Brasileira de Química, 2023-03-03) Silva, Kaique Carvalho da; Caldeira, Gabriel Rocha Figueira; Nogueira, Kenya Gomes; Canela, Maria Cristina; Filgueiras, Paulo Roberto; Souza, Murilo de OliveiraChemometrics is a subfield of chemistry that emerged from advances in analytical instrumentation and computing. When seeking to solve chemical problems that depend on many concomitants experimental variables, chemometrics can be employed in order to extract as much information as possible in the least possible number of experiments. In addition, it is possible to evaluate the important effects and interactions among the variables to understand the processes being monitored in each system. In this sense, this article aimed to develop a didactic experiment of caffeine extraction using an espresso machine, applying the 25-1 fractional factorial design. The variables studied were temperature (75 and 78 °C), pressure (2 and 15 bar), granulation (bean and ground), type of coffee (special and traditional) and period of the day (morning and afternoon) to obtain maximum extraction of caffeine. The coffee extracts obtained were analyzed using UV-Vis molecular absorption spectrophotometry. The developed experiment showed the potential to spread the application of chemometrics in the academic environment and to facilitate the teaching of fractional factorial design.Item Differences in chemical characteristics due to different roasting of robusta coffee beans(Universidade Federal de Lavras, 2023-08-23) Ramadhani, Aji Fajar; Nisa, Fithri Choirun; YuniantaRoasting is a process that contributes to the formation of compounds and flavors in coffee beans. Temperature and length of time are the main factors in the roasting process. Generally, the range of temperatures and roasting times varies significantly for different varieties of coffee beans. This study aims to determine the effect of roasting on changes in the chemical characteristics of robusta coffee beans (Coffea canephora) from Sidomulyo Village. This study used different brewing methods to brew roasted robusta coffee beans with the best chemical characteristics used a factorial randomized block design with two factors: roasting temperature, which consisted of three levels (185, 190, and 195 ⁰C), and roasting time, which consisted of three levels (10, 13, and 16 minutes). The roasted coffee beans were analyzed for water content, ash content, caffeine content, total phenol, and pH. The results of this study obtained a water content value of 3.523 ± 0.129% to 1.939 ± 0.025%, ash content of 8.119 ± 0.115% to 4.315 ± 0.260%, a caffeine content of 2.494 ± 0.015% to 2.176 ± 0.021%; total phenol of 6.251 ± 0.101% to 4.334 ± 0.117%; and a pH value of 6.675±0.126 to 4.075±0.171. At this stage, the best treatment (Zeleny method) is produced by robusta coffee beans roasted at 185⁰C for 10 minutes. Robusta coffee beans with the best treatment have a moisture content of 3.523 ± 0.129%; ash content of 4.315 ± 0.260%, the caffeine content of 2.494±0.015%; total phenol of 6.251±0.101%; and a pH value of 4.075±0.171.Item Physicochemical and sensory characteristics of dehydrated coffee pulp in function of drying temperature(Departamento de Engenharia Agrícola - UFCG, 2022-08-08) Jiménez-Ochoa, Jessica P.; Barrios-Rodríguez, Yeison F.; Bahamón-Monje, Andrés F.; Gutiérrez-Gúzman, NelsonCurrently, the use of coffee pulp to prepare infusions is being studied based on its antioxidant properties. The objective of this study was to evaluate the effect of drying temperature on the chemical properties of dehydrated coffee pulp to characterize the coffee pulp beverage in single-dose capsules physically and sensorially after being subjected to three thermal treatments (CT, natural drying; T50, oven drying at 50°C; T60, oven drying at 60°C). Chemical characterization of the dehydrated pulp was performed using Fourier transform infrared spectroscopy analysis (ATR-FTIR) and liquid chromatography (HPLC). Next, physical and sensorial characterization of the beverage was performed to determine the soluble solids (SS), pH, titratable acidity, and color. On the other hand, this beverage was evaluated sensorially. Principal component analysis was performed on the data from the FTIR spectral ranges of 1,800-650 cm-1. Physicochemical and sensory results were analyzed using ANOVA. The chemical, physical, and sensory behavioral results allowed the identification of T60 as a viable processing treatment.Item Indirect caffeine modeling in an urban river(Instituto de Pesquisas Ambientais em Bacias Hidrográficas, 2022-04-15) Peixoto, Luis Otávio Miranda; Marques, Luana Mayumi Takahasi; Mizukawa, Alinne; Azevedo, Julio Cesar Rodrigues deCaffeine is used worldwide as a chemical tracer to identify anthropic pressures on urban water resources. Nevertheless, its quantification demands great financial investments. This research created a model that would indirectly determine a range of possible caffeine concentrations along an urban river, without the need for extensive laboratory work. The model is based on Canonical Correlation Analysis (CCA), which can correlate two sets of different-sized independent and dependent variables in order to generate a single empirical equation. This equation takes as input the concentrations of ammonia nitrogen and orthophosphate, as well as the total population and the population inhabiting irregular housing areas. From the model’s results, it was possible to elaborate a spectrum of possible concentrations of caffeine along the Atuba River (Curitiba-Brazil). The tendency of water quality degradation of this river was also predicted. This model could become a useful preliminary analysis for water resource managers and researchers alike.