Previous Article | Next Article ![]()
Infection and Immunity, October 1998, p. 4640-4650, Vol. 66, No. 10
Division of Microbiology, GBF-National
Research Centre for Biotechnology, 38124 Braunschweig,
Germany,1 and
Department of Biological
Sciences, University of Wollongong, Wollongong, New South Wales
2522, Australia2
Received 30 April 1998/Returned for modification 18 June
1998/Accepted 21 July 1998
Random minitransposon mutagenesis was used to identify genes
involved in the survival of Bordetella
bronchiseptica within eukaryotic cells. One of the
mutants which exhibited a reduced ability to survive
intracellularly harbored a minitransposon insertion in a
locus (ris) which displays a high degree of homology to
two-component regulatory systems. This system exhibited
less than 25% amino acid sequence homology to the only other
two-component regulatory system described in Bordetella
spp., the bvg locus. A risA'-'lacZ translational fusion was constructed and integrated into the chromosome of B. bronchiseptica. Determination of
0019-9567/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
A Second Two-Component Regulatory System of Bordetella
bronchiseptica Required for Bacterial Resistance to Oxidative
Stress, Production of Acid Phosphatase, and In Vivo
Persistence
-galactosidase activity under different environmental conditions
suggested that ris is regulated independently of
bvg and is optimally expressed at 37°C, in the absence of
Mg2+, and when bacteria are in the intracellular niche.
This novel regulatory locus, present in all Bordetella
spp., is required for the expression of acid phosphatase by
B. bronchiseptica. Although catalase and superoxide
dismutase production were unaffected, the ris mutant was
more sensitive to oxidative stress than the wild-type
strain. Complementation of bvg-positive and
bvg-negative ris mutants with the
intact ris operon incorporated as a single copy into the
chromosome resulted in the reestablishment of the ability of the
bacterium to produce acid phosphatase and to resist oxidative stress.
Mouse colonization studies demonstrated that the ris mutant
is cleared by the host much earlier than the wild-type strain,
suggesting that ris-regulated products play a significant role in natural infections. The identification of a second
two-component system in B. bronchiseptica highlights the
complexity of the regulatory network needed for organisms with a
life cycle requiring adaptation to both the external environment and a
mammalian host.
*
Corresponding author. Mailing address: Division of
Microbiology, GBF-National Research Centre for Biotechnology,
Mascheroder Weg 1, 38124 Braunschweig, Germany. Phone: 49-531-6181558. Fax: 49-531-6181411. E-mail: cag{at}gbf.de.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»