Investigation of the functions of gamma-glutamyltranspeptidease in Salmonella

为了了解谷氨酰转氨酶(GGT)在沙门氏菌中的作用，我调查了GGT是否与沙门氏菌的毒力有关。虽然我利用GGT基因突变株分析了GGT的功能，但我没有发现GGT与沙门氏菌毒力的关系。沙门氏菌在20℃培养时，GGT活性比37℃时提高。在研究GGT活性的分子机制时，我发现Hfq基因突变株(hfq-突变株)的GGT活性比野生型沙门氏菌的GGT活性降低。此外，hfq基因互补突变体的GGT活性比hfq突变体的GGT活性高。这些结果表明，RNA伴侣Hfq参与了GGT的活性。因此，我推测沙门氏菌中GGT的产生是一种低温依赖的方式，沙门氏菌中一种新的非编码小RNA可能与GGT活性的展示有关。

To understand the role of gamma-glutamyltranspeptidase (GGT) in Salmonella, I investigated whether GGT is contributed to the Salmonella virulence. Although I analyzed the functions of GGT using the ggt gene-disrupted mutant, I could not find the association with GGT and Salmonella virulence.Salmonella was cultured at 20 C, GGT activity was elevated than that at 37 C. When I investigated the molecular mechanisms on GGT activity, I found that GGT activity in the hfq gene-disrupted mutant (hfq-mutant) was decreased compared with that of wild-type Salmonella. In addition, GGT activity in the hfq gene-complemented hfq-mutant was elevated compared with that of hfq-mutant. These results suggested that the RNA chaperone Hfq is involved in the GGT activity. Therefore, I speculated that production of GGT in Salmonella is the low temperature dependent manner and a novel non-coding small RNA in Salmonella should be associated with the exhibition of GGT activity.