Open AccessBrucella abortus d ‐alanyl‐ d ‐alanine carboxypeptidase contributes to its intracellular replication and resistance against nitric oxide
Author(s) -
Kikuchi Hiroaki,
Kim Suk,
Watanabe Kenta,
Watarai Masahisa
Publication year - 2006
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2006.00253.x
Subject(s) - nitric oxide , intracellular , microbiology and biotechnology , chemistry , alanine , biology , biochemistry , amino acid , organic chemistry
Brucella spp. are facultative intracellular pathogens that have the ability to survive and multiply in professional and nonprofessional phagocytes, and cause abortion in domestic animals and undulant fever in humans. However, the mechanism and factors of virulence are not fully understood. In the present study, a d ‐alanyl‐ d ‐alanine carboxypeptidase (DAP) mutant of Brucella abortus failed to replicate in mouse macrophages and HeLa cells, and showed less virulence than the wild type in mice. Under nitric oxide (NO) stress, the growth of the DAP mutant in vitro decreased and it also had less capability to reduce NO than the wild type. Intracellular replication of the DAP mutant was partially restored by pretreatment of macrophages with the NO synthase inhibitor, 1‐phenyl‐imidazole, and the level of expression of the NO reductase gene, norB , in the DAP mutant was lower than that in the wild type. These results suggest that DAP contributes to resistance against NO and that it is required for the intracellular growth of the bacterium.