An experiment on the use of problem-based exercises in an Indian Medical School is described. Problem-based classes were supplemented with laboratory classes and feedback from both students and tutors was analyzed.
An experiment on the use of problem-based exercises in an Indian Medical School is described. Problem-based classes were supplemented with laboratory classes and feedback from both students and tutors was analyzed.
A graphical method for analysing enzyme data to obtain kinetic parameters, to identify the types of inhibition and the enzyme mechanisms is described. The method consists of plotting experimental data as v/(V0−v) versus 1/(I) at different substrate concentrations. I is the inhibitor concentration; V0 and v are the initial rates of enzyme reaction attained by the system in the presence of a fixed amount of substrate and in the absence and presence of inhibitor respectively. Complete inhibition gives straight lines that pass through the origin while partial inhibition gives straight lines that converge on the 1/I-axis at a point away from the origin. With uncompetitive inhibition the slopes of the lines decrease with increasing substrate concentration. The kinetic parameters Km, K′i and β (degree of partiality) can best be determined from respective secondary plots of slope and intercept versus reciprocal of substrate concentration.
The present article describes a simple protocol that allows the study of nitrogen source utilisation by cells and its relation with cellular growth. The assay can be performed using the minimum of laboratory equipment.
A simple undergraduate laboratory experiment that can be used in Biochemistry and Toxicology courses to illustrate the importance of metabolic reactions in the toxicity of chemical substances is reported. It involves the experimental confirmation that oxidized phosphorothionate esters, commonly used as insecticides, are stronger cholinesterase inhibitors and therefore exhibit higher toxicity than do their sulphur analogs starting from which the first are formed by in vivo oxidative desulphuration. Two separated aliquots of a bovine blood sample are incubated with parathion and paraoxon, its oxygen analog, and compared for cholinesterase activity with “normal” blood. Previously, a standard sample of paraoxon was obtained by oxidation of the thiono group of parathion with bromine vapour by reaction TLC. The comparison of the inhibitory capacity of both compounds is made by a colorimetric procedure using acetylthiocholine as substrate of the enzyme and 5,5′-dithiobis-(2-nitrobenzoic acid) as chromogen.
The main objective of this laboratory practical class was to teach students how a detergent and the best experimental conditions are chosen to solubilize a given membrane protein. Kidney Na,K-ATPase was chosen as the protein of interest and anionic, neutral and zwitterionic detergents were tested. Simple laboratory experiments were designed to study the effect of the detergent on the activity of the enzyme, the effect of detergent concentration on solubilization, the effect of protein concentration on enzyme solubilization, and the effect of time and temperature of incubation during enzyme solubilization. This resulted in the selection of an appropriate detergent for the solubilization of the protein taking into account smaller inactivation factors, more effective solubilization (more effective solubilization with a better detergent–protein relationship), lower inactivation temperature and time of incubation of the membrane protein with the detergent. The results obtained showed that instantaneous incubation of Na,K-ATPase with C12E8 (1 : 1 w/w) at 4°C resulted in a more efficient solubilization and had a smaller denaturing effect on the solubilized enzyme.
This article describes a method for determining some antioxidant enzyme activities (catalase and/or glutathione peroxidase) and the oxidative status (protein oxidative damage and/or lipid peroxidation) of human blood. However, the main objective of the work is to illustrate the relationship between antioxidant defences and oxidative damage, showing to students their correlation and the general importance of the biochemical regulation in health and diseases.
This article describes a method for determining some antioxidant enzyme activities (catalase and/or glutathione peroxidase) and the oxidative status (protein oxidative damage and/or lipid peroxidation) of human blood. However, the main objective of the work is to illustrate the relationship between antioxidant defences and oxidative damage, showing to students their correlation and the general importance of the biochemical regulation in health and diseases.
Post graduate research students need to undertake programs that will develop their potential as a scientist. They need to acquire skills to develop scientific argument, design an experimental approach to test a hypothesis, obtain and analyse data, and effectively communicate their ideas and findings to the scientific community. Many biotechnology-based programs are now funded by industry partnerships and integrating post graduate students into these programs require special considerations.
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