Applications of bioluminescence in toxicity tests and microbial physiology

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Liu, X., 2006. Applications of bioluminescence in toxicity tests and microbial physiology. PhD, Nottingham Trent University.

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Abstract

Bioluminescence in general was reviewed before several applications of bacterial luminescence were described in details, which generally include toxicity test and microbial physiology. The first application of bioluminescence was the toxicity testing of end-products from anaerobic and aerobic microbial decolourisation of azo dyes (Sunset Yellow, Orange II, Reactive Black 5 and Acid Red 183). The bacterium Enterococcus faecalis reduced selective azo dyes in less than one hour, while the white-rot fungus Trametes versicolor needed about 13 days in total for decolourisation. The end products from the bacterial decolourisation were more toxic than the fungi. Toxicity was assessed using the standard Vibrio fischeri bioluminescence assay (ToxAlert 100). The toxicity of naphthol compounds was also assessed using genetic modified bioluminescent E. coli, Ps. putida as well as marine bacteria V. fischeri. These bacteria responded differently to naphthol-based compounds, which are generated from bacterial decolourisation of azo dyes. The second application of bioluminescence was construction of bioluminescent Campylobacter jejuni, which is a well-known cause of diarrhoeal disease. A final application of bioluminescence was related to Enterobacter sakazakii, and related organisms. These organisms cause bacteraemia, meningitis and other diseases in neonates and immuno-compromised adults. All strains used were previously isolated from dried food. They retained their viability even after begin exposed to stress conditions; desiccation and acidic pH environment. How quick these bacteria recovered from stressed states was unknown, protein synthesis activity during the bacteria recovery from extreme conditions was monitored in this study using bioluminescence and fluorescence markers. E. sakazakii, C. koseri and related organisms were genetically regrouped by PCR methods prior to the reporter strain construction. Initial transposon modified bioluminescent bacteria were regarded not appropriate for the study as no promoter information was available. Ribosomal protein promoter was used to construct bioluminescent and GFP E. sakazakii and C. koseri, as the ribosomal protein promoter can represent the ribosomal activity. The result shows that the bacteria required 1-3 hours to recover from the desiccated condition prior to protein synthesis. This was dependent upon the pH. The recovery period for pH 7, 6 and 5 were 2.5, 4.5 and 7 hours, respectively.

Item Type:

Thesis

Creators:

Liu, X.

Date:

2006

ISBN:

9781369324631

Identifiers: