Adsorption of methylene blue and malachite green was carried out using Luf fa cylindrica sponges as adsorbing material. We provide a very illustrative exercise about the use of common natural materials requiring little preparation to solve environmental tasks in a routine laboratory situation such as using dyes. In addition, the experiment can be used in different study levels. We illustrate the use of spectrophotometric techniques, calibrations, or (in a more advanced level) calculations of adsorption kinetics and the use of statistical tools in data treatment. The use of natural fibers to remove dyes from laboratory wastewater highlights the environmental responsibility of undergraduate students by training them to treat common laboratory pollutants, and on the other hand, it offers an efficient tool to illustrate water remediation procedures.

El cianuro se considera una especie altamente tóxica para cualquier ecosistema debido a que causa enfermedades en seres humanos, contribuye a la pérdida de fertilidad en suelos y contamina fuentes de agua constituyendo un factor importante en mortalidad de flora y fauna acuática. El presente trabajo evalúa el estropajo (Luffa Cylindrica) como material adsorbente de origen natural para retener ion cianuro en medio acuoso; los ensayos realizados se llevaron a cabo a través de la aplicación de un diseño experimental tipo factorial, evaluando variables como pH y tiempo de contacto en dos niveles. Las condiciones adecuadas para retener el ion cianuro fueron pH de 9,0 y un tiempo de contacto de 10 minutos, el comportamiento adsorbente – adsorbato se representa por la isoterma de Freundlich, el modelo cinético de adsorción se ajusta a pseudo-segundo orden. Se obtuvieron porcentajes de retenciones de ion cianuro que van desde 12.2 hasta 98.0%.

The inhibition of porcine pancreatic lipase by the drug orlistat was studied through a series of activities that combine experimental and computational procedures. The enzymatic activity of the lipase was determined by measuring enzyme kinetics and calculating parameters such as K m and V max from experimental data. Assays of lipase inhibition by orlistat were used to construct Linewaver−Burk and Dixon plots. Docking calculations are highly recommended to visualize the enzyme−ligand interactions and as an approach to decipher the inhibitor mechanism of action. Furthermore, sequence analysis was included to compare enzyme structures across different organisms, specifically between human and pig as closely related study models, and complement the docking simulations. The educational project proposed here for biochemistry or pharmacy students can enhance the understanding of concepts regarding enzyme kinetics, binding sites, and enzyme−ligand interactions through visualizations.

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Como citar este artículo: Naranjo J, Dueñas Y, Caicedo O, Castrillón A. Evaluación de propiedades fisicoquímicas de aceite de girasol (Helianthus annuus) adicionado con extracto de Bixa orellana durante calentamiento en horno microondas. Perspect Nutr Humana. 2015;17: 115-124 Evaluation of physicochemical properties of sunflower oil (Helianthus annuus) blended with achiote (Bixa orellana) extract during microwave heating AbstractBackground: Microwave cooking is a growing trend in the general population, which does not take into account the effect on food quality. Objective: To evaluate the effect of the extract of Bixa orellana on sunflower oil during microwave heating. Materials and methods: Sunflower oil was heated during 12 minutes in a microwave, with and without the addition of 100 mg extract of Bixa orellana, and physicochemical properties were evaluated at different time intervals. Results: The addition of Bixa orellana extract contributes to preserve the quality of the sunflower oil during the first three minutes of heating. For longer periods, no protective effect is observed. Conclusion: The addition of 100 mg of extract of Bixa orellana on sunflower oil was capable to avoid the oxidation during microwave heating for three minutes.