Histamine-Producing Pathway Encoded on an Unstable Plasmid in Lactobacillus hilgardii 0006

摘要: Histamine production from histidine in fermented food products by lactic acid bacteria results spoilage and is harmful to consumers. We have isolated a histamine-producing bacterium, Lactobacillus hilgardii strain IOEB 0006, which could retain or lose the ability produce histamine depending on culture conditions. The hdcA gene, coding for decarboxylase of L. was located an 80-kb plasmid that proved be unstable. Sequencing locus disclosed four-gene cluster encoding decarboxylase, protein unknown function, histidyl-tRNA synthetase, protein, we named HdcP, showing similarities integral membrane transporters driving substrate/product exchange. gene HdcP cloned downstream sequence specifying tag expressed Lactococcus lactis. recombinant drive uptake into cell exchange histamine. combination forms typical bacterial decarboxylation pathway may generate metabolic energy involved stress response. Analyses sequences present databases suggest other two proteins dispensable functions. These describe first time genes provide clues parsimonious distribution instability bacteria.