?-galaktosidas assay för studie av promotorregion i kloritdismutas från Ideonella dechloratans
Oxochlorates are anions with a partially naturally occurrence in nature but are also spread by human activities, including the paper industry. These compounds are harmful to both nature and humans, which makes it necessary to find a good way for their degradation. There are two different kinds of bacteria that can use oxochlorates as electron acceptors in their metabolism, bacteria that break down perchlorate and bacteria that break down both perchlorate and chlorate. A bacterium that can break down chlorate under anaerobic conditions is Ideonella dechloratans which holds the genes for chlorite dismutase and chlorate reductase which are enzymes for the degradation of chlorate. Gene expression and enzyme activity of chlorite dismutase are induced under anaerobic conditions, which makes it interesting to find out how this regulation functions in order to better exploit these bacteria in biological wastewater treatment. To study the expression of the gene for chlorite dismutase a potential promoter and regulatory sequence has previously been cloned in a reporter vector and transformed into Escherichia coli (E.coli) bacterium XL-1 blue. This work was to develop a ?-galactosidase assay for the quantification of gene expression in this system and apply it to aerobic and anaerobic bacterial cultures. The method was optimized for cultivation in LB-medium and measurements of gene expression showed higher promoter activity during anaerobic compared with aerobic culture conditions for all of the studied clones. This means that all the clones contain a sequence which can function as promoter in E. coli, and that its activity increases during anaerobic conditions.