Brucellosis 2003 proceedings - PHIDIAS

Poster Session
109- COMPARATIVE PROTEOMIC ANALYSIS OF Brucella suis BIOVARS 1 AND
2 USING TWO-DIMENSIONAL GEL ELECTROPHORESIS AND MASS
SPECTROMETRY.
M.S. Zygmunt , C. Boursier and F. Carreras. Unité de Pathologie Infectieuse et Immunologie, Institut
National de la Recherche Agronomique, F-37380, Nouzilly, France.
Brucella suis is a Gram-negative, facultative, intracellular pathogen that
causes brucellosis in both domestic and feral pigs. Porcine brucellosis is
characterized by abortion, low production, infertility, and arthritis in infected animals.
B. suis can also cause a serious infection in humans characterized by a systemic,
febrile illness. Although B. suis (biovars 1, 2 and 3) is still widely distributed in the
world, prevalence in domestic pigs is low excepted in South-East Asia and South
America. Since approximately 10 years, B. suis biovar 2 is emerging in outdoor
breedings of domestic pigs in France. The population of wild boars in this country are
largely contaminated by B. suis biovar 2 with up to 40% of serological prevalence. It
is well known that transmission of B. suis biovar 2 between wild boars and domestic
pigs is possible. However, no definitive explanation has been provided for the lower
pathogenicity of this biovar for the wild boars compared to domestic pigs. Moreover,
in contrast to B. suis biovar 1, human infections with B. suis biovar 2 have not yet
been reported . In the present study, we compared the proteome of B. suis biovar 1,
for which the genome sequence has recently been released and published, to that of
strains of B. suis biovar 2, by using two-dimensional gel electrophoresis and matrixassisted
laser desorption/ionization (MALDI)-mass spectrometry (MS), to elucidate
differences between the protein expression pattern of the two biovars and to identify
potential molecular markers related to host preferentialism. Differentially expressed
proteins involved in sugar transport, amino acid binding, oxydative pathways were
identified. Expression of an immunogenic 31-kDa protein was altered in B. suis
biovar 1.
110- IN SILICO ANALYSIS OF THE CtrA REGULON IN ALPHA
PROTEOBACTERIA.
R.HALLEZ, A. F. BELLEFONTAINE, C. LAMBERT, J-J. LETESSON, J. VANDENHAUTE AND X. DE
BOLLE. Unité de Recherche en Biologie Moléculaire (URBM), Laboratoire de Microbiologie et de
Génétique Moléculaire, Facultés Universitaires Notre-Dame de la Paix, B-5000 Namur, Belgium.
CtrA is a transcriptional regulator found in all alpha proteobacteria analysed to
date. In this group, we find notably the free living bacterium Caulobacter crescentus,
the plant’s symbionts Sinorhizobium meliloti and Mesorhizobium loti, the plant’s
pathogen Agrobacterium tumefaciens, or yet the facultative or obligate animal’s
pathogens Brucella sp. or Rickettsia prowazekii, respectively. In C. crescentus, CtrA
is controlled by a complex multicomponent signal transduction system that regulates
and synchronises multiple cell cycle events (Quon et al., 1996). All the promoters
directly regulated by CtrA contain a characteristic DNA motif (TTAA-N7-TTAAC or
TTAACCAT), defined as the CtrA binding sites since CtrA is able to bind it in vitro
and in vivo (Laub et al, 2002). We analysed the CtrA regulon in other alpha
proteobacteria to get a better understanding of the CtrA role in these bacteria. The
release of the alpha proteobacterial genomes has permitted us to characterize in
silico both the upstream and downstream pathways of CtrA regulons. Our results
indicate first that the upstream regulating pathway is partially conserved between
152
Brucellosis 2003 International Research Conference