摘要：NADH oxidase activity has been found in a number of host-associated bacterial species by previous investigators. NADH oxidase may play an essential role in the colonisation of the mammalian intestinal tract by diverse bacterial species. In this study, 45 strains of intestinal spirochaetes were screened for NADH oxidase by enzyme assay and by using an oligodeoxynucleotide probe (5'-ATGAAAGT(TA)AT(TA)GT(TA)AT(TA)GG-3') complementary to the 5'-end of the NADH oxidase (nox) gene from Serpulina (Treponema) hyodysenteriae B204. The strains surveyed included 18 strains of S. hyodysenteriae, S. innocens strains B256 and 4/71, Treponema succinifaciens 6091, T. bryantii RUS-1, and 23 strains of uncharacterised (unclassified) intestinal spirochaetes. The uncharacterised spirochaetes had been isolated from the intestinal contents of different animal hosts (human, swine, avian, nutria). NADH oxidase was absent from T. succinifaciens and T. bryantii, but was present in every strain of S. hyodysenteriae, in the two recognised strains of S. innocens, and in every uncharacterised strain of intestinal spirochaete. Cells of four strains contained NADH oxidase activity but their DNA did not react with the probe. NADH oxidase is a common enzyme for the intestinal spirochaetes included in this survey.Keywords: NADH oxidase; spirochaete; intestinal bacteria; Serpulina hyodysenteriae; nox; intestinal microecology.
