 |
Sandra K. Armstrong,
Ph.D.
Associate Professor
Department of Microbiology
University of Missouri-Columbia, 1986, Ph.D.
armst018@umn.edu
612-625-6947 office
612-624-5177 lab
|
Research Interests:
Iron Acquisition in Pathogenic Bacteria
Virtually all organisms require nutritive iron and its assimilation
is essential for invading pathogenic bacteria to establish
infection in the iron-limiting environment of the host. Research
in my laboratory is centered on Gram-negative bacterial pathogens
of humans and nonhuman hosts.
Bordetella pertussis, Bordetella bronchiseptica and
Bordetella parapertussis are mammalian respiratory
pathogens that are highly genetically-related Gram-negative
members of the family Alcaligenaceae. B. pertussis,
the agent of whooping cough (pertussis), is an obligate human
pathogen. B. parapertussis causes respiratory infections
in humans and sheep, and B. bronchiseptica
infects nonhuman mammals, causing kennel cough in dogs, atrophic
rhinitis in swine and snuffles in rabbits. These Bordetella
species obtain iron supplied by their native iron-chelating
siderophore, alcaligin, as well as siderophores produced by
other microbial species (termed xenosiderophores) and from
host iron containing compounds including heme and hemoglobin.
These iron retrieval systems are expressed when the bacteria
are starved for iron and they are further activated by cognate
transcriptional regulators that respond to the presence of
the specific iron compound. Our studies are aimed at analyzing
the cis- and trans-acting determinants involved
in transcriptional regulation of these iron utilization genes
with the long range objective of understanding the processes
governing the expression of different Bordetella
iron acquisition in the host.
Francisella tularensis is a facultative intracellular
bacterial pathogen that is highly infectious and can cause
severe disease, however very little is known about its biology
and pathogenic mechanisms. Our studies are aimed at defining
the mechanisms by which F. tularensis satisfies its
nutritional and metabolic requirements in the host environment.
Cell-Cell Signaling
Another project in my laboratory is the study of bacterial
intercellular communication by the excretion and perception
of signaling molecules. Recent experiments have identified
molecules produced by Bordetella pertussis and Bordetella
bronchiseptica that possess potent intercellular signaling
activity. My lab is focused on determining whether Bordetella
cells communicate with one another in the host during the
course of infection, and whether this communication is required
for optimal growth and regulation of the expression of known
virulence factors.
Selected Recent Publications:
- Anderson, M.T., Armstrong, S.K. 2006. The Bordetella bfe system: growth and transcriptional response to siderophores, catechols, and neuroendocrine catecholamines. J Bacteriol. 188(16):5731-40.
- Brickman, T.J., Vanderpool, C.K., Armstrong, S.K. 2006. Heme transport contributes to in vivo fitness of Bordetella pertussis during primary infection in mice. Infect Immun. 74(3):1741-4.
- Brickman, T.J., Armstrong, S.K. 2005. Bordetella AlcS transporter functions in alcaligin siderophore export and is central to inducer sensing in positive regulation of alcaligin system gene expression. J Bacteriol. 2005 Jun;187(11):3650-61.
- Anderson, M.T. and S.K. Armstrong. 2004. The BfeR regulator mediates enterobactin-inducible expression of Bordetella enterobactin utilization genes. J. Bacteriol. 186:7302-7311.
- Brickman, T.J., C.K. Vanderpool and S.K. Armstrong. 2004. Bordetella, p. 311-328. In Crosa, Mey and Payne,(ed.), Iron Transport in Bacteria; American Society for Microbiology, Washington, D.C.
- Vanderpool, C.K. and S.K. Armstrong. 2004. Integration of environmental signals controls expression of Bordetella heme utilization genes. J. Bacteriol. 186:938-948.
- Vanderpool, C.K. and S.K. Armstrong. 2003. Heme-responsive transcriptional activation of Bordetella bhu genes. J. Bacteriol. 185:909-917.
- Brickman, T.J. and S.K. Armstrong. 2002. Alcaligin siderophore production by Bordetella bronchiseptica strain RB50 is not repressed by the BvgAS virulence control system. J. Bacteriol. 184:7055-7057.
- Brickman, T.J. and S.K. Armstrong. 2002. Bordetella interspecies allelic variation in AlcR inducer requirements: identification of a critical determinant of AlcR inducer responsiveness and construction of an alcRCon mutant allele . J. Bacteriol. 184:1530-1539.
- Brickman, T.J., H.Y. Kang, and S.K. Armstrong. 2001.
Transcriptional activation of Bordetella alcaligin
siderophore genes requires the AlcR regulator with alcaligin
as inducer. J.
Bacteriol. 183:483-489.
- Vanderpool, C.K. and S.K. Armstrong. 2001. The Bordetella
bhu locus is required for heme iron utilization. J.
Bacteriol. 183:4278-4287.
Last modified on: October 24, 2006 |
