ISSUES IN BIOTECHNOLOGY TEACHING - Teaching of Biotechnology in the Biochemistry Course

Biotechnology is taught in the Biochemistry course of the Faculty of Science of the Lisbon University during the last year of the course divide into two semesters. These two disciplines are optional with other disciplines that the students may choose in order to complete their knowledge in Biochemistry. Both disciplines have two credits, one for theory and the other for laboratory: Applied Biochemistry, comes in the first semester and Immobilized Biocatalysts in the second. Each discipline is taught during 13 weeks. The main goal of these two disciplines in the Biochemistry course is to give the students an applied vision, devoted to the industry, of the Biochemistry they have been taught during the previous three years

NADH oxidase activity of rat and human liver xanthine oxidoreductase: potential role in superoxide production

J Biol Inorg Chem (2007) 12:777–787 DOI 10.1007/s00775-007-0229-7To characterise the NADH oxidase activity of both xanthine dehydrogenase (XD) and xanthine oxidase (XO) forms of rat liver xanthine oxidoreductase (XOR) and to evaluate the potential role of this mammalian enzyme as an O2*- source, kinetics and electron paramagnetic resonance (EPR) spectroscopic studies were performed. A steady-state kinetics study of XD showed that it catalyses NADH oxidation, leading to the formation of one O2*- molecule and half a H(2)O(2) molecule per NADH molecule, at rates 3 times those observed for XO (29.2 +/- 1.6 and 9.38 +/- 0.31 min(-1), respectively). EPR spectra of NADH-reduced XD and XO were qualitatively similar, but they were quantitatively quite different. While NADH efficiently reduced XD, only a great excess of NADH reduced XO. In agreement with reductive titration data, the XD specificity constant for NADH (8.73 +/- 1.36 microM(-1) min(-1)) was found to be higher than that of the XO specificity constant (1.07 +/- 0.09 microM(-1) min(-1)). It was confirmed that, for the reducing substrate xanthine, rat liver XD is also a better O2*- source than XO. These data show that the dehydrogenase form of liver XOR is, thus, intrinsically more efficient at generating O2*- than the oxidase form, independently of the reducing substrate. Most importantly, for comparative purposes, human liver XO activity towards NADH oxidation was also studied, and the kinetics parameters obtained were found to be very similar to those of the XO form of rat liver XOR, foreseeing potential applications of rat liver XOR as a model of the human liver enzyme

Glycation potentiates α-synuclein-associated neurodegeneration in synucleinopathies

publishersversionpublishe

Optimization of Time-Course Experiments for Kinetic Model Discrimination

Systems biology relies heavily on the construction of quantitative models of biochemical networks. These models must have predictive power to help unveiling the underlying molecular mechanisms of cellular physiology, but it is also paramount that they are consistent with the data resulting from key experiments. Often, it is possible to find several models that describe the data equally well, but provide significantly different quantitative predictions regarding particular variables of the network. In those cases, one is faced with a problem of model discrimination, the procedure of rejecting inappropriate models from a set of candidates in order to elect one as the best model to use for prediction

Beyond Genetic Factors in Familial Amyloidotic Polyneuropathy: Protein Glycation and the Loss of Fibrinogen's Chaperone Activity

Familial amyloidotic polyneuropathy (FAP) is a systemic conformational disease characterized by extracellular amyloid fibril formation from plasma transthyretin (TTR). This is a crippling, fatal disease for which liver transplantation is the only effective therapy. More than 80 TTR point mutations are associated with amyloidotic diseases and the most widely accepted disease model relates TTR tetramer instability with TTR point mutations. However, this model fails to explain two observations. First, native TTR also forms amyloid in systemic senile amyloidosis, a geriatric disease. Second, age at disease onset varies by decades for patients bearing the same mutation and some mutation carrier individuals are asymptomatic throughout their lives. Hence, mutations only accelerate the process and non-genetic factors must play a key role in the molecular mechanisms of disease. One of these factors is protein glycation, previously associated with conformational diseases like Alzheimer's and Parkinson's. The glycation hypothesis in FAP is supported by our previous discovery of methylglyoxal-derived glycation of amyloid fibrils in FAP patients. Here we show that plasma proteins are differentially glycated by methylglyoxal in FAP patients and that fibrinogen is the main glycation target. Moreover, we also found that fibrinogen interacts with TTR in plasma. Fibrinogen has chaperone activity which is compromised upon glycation by methylglyoxal. Hence, we propose that methylglyoxal glycation hampers the chaperone activity of fibrinogen, rendering TTR more prone to aggregation, amyloid formation and ultimately, disease

Effect of dietary palm oil on growth and carcass composition of Heterobranchus longifilis fingerlings

This study investigated the effects of dietary palm oil (PO) on growth performance and carcass composition of Heterobranchus longifilis with the goal of replacing dietary fish oil with palm oil. In this study triplicate groups of H. longifilis fingerlings were fed the experimental diets for 8 weeks. Five isonitrogenous (45% crude protein), isoenergetic (20 KJg-1) experimental diets were made containing either 6.0% FO and 0% PO, 4.5% FO and 1.5% PO; 3.0% FO and 3.0% PO; 1.5% FO and 4.5% PO; or 0% FO and 6.0% PO using soybean and fish meal as the protein source. Dietary palm oil had no significant effect on growth rate or feed conversion ratio. Similarly, No significant differences were observed between dietary treatments for moisture, protein and ash content in H. longifilis fingerlings. However, fillet saturated, monounsaturated fatty acids and liver lipid deposition were significantly (P0.05) higher in fish fed 6.0% PO diet. This study suggests that the replacement of cod liver oil by palm oil as lipid supplement in the diet permitted a clear improvement of growth and FCR of H. longifilis. This indicates that PO can effectively replace FO in the diet of the fish without compromising fish growth and feed efficiency