RESUMO
OBJECTIVES: Mycobacterium tuberculosis is a deadly human pathogen that causes the lung disease TB. M. tuberculosis latently infects a third of the world's population, resulting in â¼1.5 million deaths per year. Due to the difficulties and expense of carrying out animal drug trials using M. tuberculosis and rodents, infections of the zebrafish Danio rerio with Mycobacterium marinum have become a useful surrogate. However, the infection methods described to date require specialized equipment and a high level of operator expertise. METHODS: We investigated whether zebrafish larvae could be naturally infected with bioluminescently labelled M. marinum by immersion, and whether infected larvae could be used for rapid screening of anti-mycobacterial compounds using bioluminescence. We used rifampicin and a variety of nitroimidazole-based next-generation and experimental anti-mycobacterial drugs, selected for their wide range of potencies against M. tuberculosis, to validate this model for anti-mycobacterial drug discovery. RESULTS: We observed that five of the six treatments (rifampicin, pretomanid, delamanid, SN30488 and SN30527) significantly reduced the bioluminescent signal from M. marinum within naturally infected zebrafish larvae. Importantly, these same five treatments also retarded the growth of M. tuberculosis in vitro. In contrast, only three of the six treatments tested (rifampicin, delamanid and SN30527) retarded the growth of M. marinum in vitro. CONCLUSIONS: We have demonstrated that zebrafish larvae naturally infected with bioluminescent M. marinum M can be used for the rapid screening of anti-mycobacterial compounds with readily available equipment and limited expertise. The result is an assay that can be carried out by a wide variety of laboratories for minimal cost and without high levels of zebrafish expertise.
Assuntos
Antituberculosos/isolamento & purificação , Antituberculosos/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Mycobacterium marinum/efeitos dos fármacos , Peixe-Zebra/microbiologia , Animais , Larva/microbiologia , Medições Luminescentes , Mycobacterium marinum/crescimento & desenvolvimento , Nitroimidazóis/farmacologia , Rifampina/farmacologia , Coloração e RotulagemRESUMO
The nutrient content of 85 cooked dishes has been calculated using McCance and Widdowson's 'The composition of foods' (Paul & Southgate, 1978). The nutrients covered were energy, fat, protein, carbohydrates, ten minerals and 12 vitamins. Recipes for each dish and the factors used to estimate losses of water in cooking are included.