M. Tsuda et al., ESSENTIAL ROLE OF HELICOBACTER-PYLORI UREASE IN GASTRIC COLONIZATION - DEFINITE PROOF USING A UREASE-NEGATIVE MUTANT CONSTRUCTED BY GENE REPLACEMENT, European journal of gastroenterology & hepatology, 6, 1994, pp. 49-52
Objective: To investigate the involvement of urease in Helicobacter py
lori colonization in the nude mouse stomach by using a genetically def
ined urease-negative mutant. Methods and results: Through electroporat
ion-mediated gene replacement, one of the urease genes of an H. pylori
strain, CYP3401, was disrupted by insertion of a kanamycin-resistance
determinant to construct a stable urease-negative mutant, HPT73. Sout
hern analysis confirmed that gene replacement was achieved. The two is
ogenic strains were introduced into the stomachs of nude mice, and the
number of H. pylori and the histological changes in the stomachs were
investigated 1 or 4 weeks after the challenge. Gastritis was present
in the CPY3401-challenged stomach, from which bacteria indistinguishab
le from CPY3401 were successfully recovered. In contrast, no gastritis
was found in the HPT73-challenged stomach, and H. pylori was not reco
vered from these stomachs. Conclusion: H. pylori urease is essential f
or colonization of the nude mouse stomach.