ABSTRACT
AIMS: The aim of the study was to characterize 10 hemicellulolytic enzymes obtained from a wheat straw-degrading microbial consortium. METHODS AND RESULTS: Based on previous metagenomics analyses, 10 glycosyl hydrolases were selected, codon-optimized, synthetized, cloned and expressed in Escherichia coli. Nine of the overexpressed recombinant proteins accumulated in cellular inclusion bodies, whereas one, a 37·5-kDa protein encoded by gene xylM1989, was found in the soluble fractions. The resulting protein, denoted XylM1989, showed ß-xylosidase and α-arabinosidase activities. It fell in the GH43 family and resembled a Sphingobacterium sp. protein. The XylM1989 showed optimum activity at 20°C and pH 8·0. Interestingly, it kept approximately 80% of its ß-xylosidase activity in the presence of 0·5% (w/v) furfural and 0·1% (w/v) 5-hydroxymethylfurfural. Additionally, the presence of Ca2+ , Mg2+ and Mn2+ ions increased the enzymatic activity and conferred complete tolerance to 500 mmol l-1 of xylose. Protein XylM1989 is also able to release sugars from complex polysaccharides. CONCLUSION: We report the characterization of a novel bifunctional hemicellulolytic enzyme obtained through a targeted synthetic metagenomics approach. SIGNIFICANCE AND IMPACT OF THE STUDY: The properties of XylM1989 turn this protein into a promising enzyme that could be useful for the efficient saccharification of plant biomass.
ABSTRACT
Food misdescription has become of paramount importance as consumers come into contact daily with a great variety of foods. The controversies surrounding genetically modified organism (GMO) labelling and malpractices in the food chain have forced regulatory authorities to authenticate food from production to consumption. This paper reports the results of a surveillance programme conducted in the United Arab Emirates (UAE) market to assess the status of food misdescription and authenticity. A DNA test was used to screen random samples of processed meat products bought from supermarkets in the UAE. A total of 246 samples were analysed from different geographical locations. The majority of samples showed a high standard of legal compliance, with over 95% confirmed for authenticity. However, 5% of samples were found to contain undeclared species. In conclusion, this study confirms the presence of undeclared food in the UAE market. Regular surveillance and monitoring programmes along with strict implementation of the Food and Adulteration Act may alleviate misdescription issues to a greater extent.
Subject(s)
Consumer Product Safety , Food Contamination , Food Labeling , Meat Products/analysis , Meat/analysis , Animals , Consumer Product Safety/legislation & jurisprudence , DNA/analysis , DNA/metabolism , Food Contamination/legislation & jurisprudence , Food Labeling/legislation & jurisprudence , Guideline Adherence , Humans , Legislation, Food , Meat/adverse effects , Meat/economics , Meat/standards , Meat Products/adverse effects , Meat Products/economics , Meat Products/standards , Polymerase Chain Reaction , Public Health Surveillance , United Arab EmiratesABSTRACT
The Department of Community Health Christian Medical College, Vellore, India, developed a module in 1981 to teach filariasis to medical undergraduates, using a community-based approach aimed at providing a comprehensive picture of this disease. Students learn in four phases during the 5 1/2 years they spent in medical school. Student assessment is done during and at the end of each phase. Student feedback of the programme has been very positive. This paper describes the salient features of the module and suggests it could be adopted by other institutions to teach tropical diseases of public health importance that are relevant to that particular region or country.
