Histamine, one of the most toxic and commonly encountered biogenic amines (BA) in food, is produced by the microbial decarboxylation of histidine. It may accumulate at high concentrations in fish and fermented food. Cheese has some of the highest histamine concentrations, the result of the histidine-decarboxylase activity of certain lactic acid bacteria (LAB). The present work describes the nucleotide sequence and transcriptional organization of the gene cluster responsible for histamine biosynthesis (the HDC cluster) in Lactobacillus vaginalis IPLA 11064 isolated from cheese. The influence of histidine availability and pH on histamine production and the expression of the HDC cluster genes is also examined. As expected, the results suggest that the production of histamine under acidic conditions improves cell survival by maintaining the cytosol at an appropriate pH. However, the transcriptional regulation of the HDC cluster is quite different from that described in other dairy histamine-producing LAB, probably due to the lack of a termination-antitermination system in the histidyl-tRNA synthetase gene (hisS).

组胺是食物中毒性最高，最常见的生物胺（BA）之一，它是通过组氨酸的微生物脱羧作用产生的。它可能在鱼类和发酵食品中高浓度积累。奶酪具有某些最高的组胺浓度，这是某些乳酸菌（LAB）的组氨酸脱羧酶活性的结果。本工作描述了从奶酪分离的阴道乳酸杆菌IPLA 11064中负责组胺生物合成的基因簇（HDC簇）的核苷酸序列和转录组织。组氨酸利用率和pH值对组胺产生和HDC表达的影响还检查了簇基因。如所预期的，结果表明在酸性条件下组胺的产生通过将细胞溶质维持在适当的pH来改善细胞存活。但是，HDC簇的转录调控与其他乳品组胺生产实验室中描述的调控完全不同，这可能是由于组氨酸-tRNA合成酶基因（hisS）中缺少终止-终止系统。