We report the complete and annotated genome sequence of the animal pathogen Listeria ivanovii subsp. ivanovii strain PAM 55 (serotype 5), isolated in 1997 in Spain from an outbreak of abortion in ...sheep. The sequence and its analysis are available at an interactive genome browser at the Institut Pasteur (http://genolist.pasteur.fr/LivaList/).
The aim of this study was to characterize the capillary density, progression and persistence of new capillaries induced by different isoforms of vascular endothelial growth factor (VEGF)-A. They were ...produced and purified using the same protocol and assessed in the same experimental model, the rabbit cornea assay. Monogenic homodimers for VEGF121 and VEGF165 together with the heterodimer VEGF121/165 were tested as slow release polymer pellets implanted into the avascular rabbit cornea and examined up to 18 days post-implantation. The implants consistently stimulated angiogenesis in the absence of inflammation. The VEGF121 isoform produced the strongest increase of new capillary vessels which rapidly and persistently progressed into the corneal stroma. VEGF165 promoted the growth of a smaller number of capillaries which ten-ded to regress over time. Heterodimers of VEGF121/165 produced intermediate in vivo activities between the two homodimers. In vitro endothelial cell proliferation, mobilization and adhesion were promoted by all VEGF isoforms under serum-free or serum-reduced conditions with the same order of potency. Anti-soluble KDR (sKDR) antibody completely inhibited the effects of all the isoforms. These results indicate that monogenic homodimer preparations of VEGF121 and VEGF165 can display distinct biological effects which are functionally retained after the heterodimeric assembly of VEGF121 and VEGF165. The observed different biological behavior of the VEGF isoforms reveals the possibility that in vivo the assembly of dimers derived from splicing of a single gene may yield molecules with either different matrix or receptor interaction, stability or diffusion rate according to specific needs.
We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron–positron colliders SLC and LEP. The data consist of 17 ...million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLD experiment using a polarised beam at SLC. The measurements include cross-sections, forward–backward asymmetries and polarised asymmetries. The mass and width of the Z boson,
m
Z
and
Γ
Z
, and its couplings to fermions, for example the
ρ
parameter and the effective electroweak mixing angle for leptons, are precisely measured:
m
Z
=
91.1875
±
0.0021
GeV
,
Γ
Z
=
2.4952
±
0.0023
GeV
,
ρ
ℓ
=
1.0050
±
0.0010
,
sin
2
θ
eff
lept
=
0.23153
±
0.00016
.
The number of light neutrino species is determined to be
2.9840
±
0.0082
, in agreement with the three observed generations of fundamental fermions.
The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward–backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations.
Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark,
m
t
=
173
-
10
+
13
GeV
, and the mass of the W boson,
m
W
=
80.363
±
0.032
GeV
. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of
m
t
and
m
W
, the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than
285
GeV
at 95% confidence level.
The four LEP Collaborations, ALEPH, DELPHI, L3 and OPAL, have collected a total of 2461 pb−1 of e+e− collision data at centre-of-mass energies between 189 and 209 GeV. The data are used to search for ...the Standard Model Higgs boson. The search results of the four Collaborations are combined and examined in a likelihood test for their consistency with two hypotheses: the background hypothesis and the signal plus background hypothesis. The corresponding confidences have been computed as functions of the hypothetical Higgs boson mass. A lower bound of 114.4 GeV/c2 is established, at the 95% confidence level, on the mass of the Standard Model Higgs boson. The LEP data are also used to set upper bounds on the HZZ coupling for various assumptions concerning the decay of the Higgs boson.
Extracellular proteins of bacterial pathogens play a crucial role in the infection of the host. Here we present the first comprehensive validation of the secretory subproteome of the Gram positive ...pathogen Listeria monocytogenes using predictive bioinformatic and experimental proteomic approaches. The previous original signal peptide (SP) prediction (Glaser et al., Science 2001, 294, 849–852) has been greatly improved by an in‐depth analysis using seven different bioinformatic tools. Subsequent careful classification of the resulting data gives a probability dependent annotation of 121 putatively secreted proteins of which 45 are novel. Complementary proteomic analysis using both two‐dimensional gel electrophoresis/matrix assisted laser desorption/ionization mass spectrometry and high performance liquid chromatography/electrospray ionization‐mass spectrometry has identified 105 proteins in the culture supernatant of L. monocytogenes. Among these, we were able to detect all the currently known virulence factors with an SP showing the importance of this subproteome and demonstrating the reliability of the techniques used. The comparison between the L. monocytogenes wildtype and the nonpathogenic species Listeria innocua was performed to reveal proteins probably involved in pathogenicity and/or the adaptation to their respective lifestyles. In addition to the eight known virulence factors, all of which have no orthologous genes in L. innocua, eight additional proteins have been identified that exhibit the typical key feature defining the known listerial virulence factors. Further significant differences between the two species are evident in the group of cell wall and secretory proteins that warrant further study. Our investigation clearly demonstrates that the major difference between the pathogenic and nonpathogenic species, noted in the comparative genome analysis, manifests itself strongest in the secretome.
The surface subproteome of Listeria monocytogenes that includes many proteins already known to be involved in virulence and interaction with host cells has been characterized. A new method for the ...isolation of a defined surface proteome of low complexity has been established based on serial extraction of proteins by different salts at high concentration, and in all 55 proteins were identified by N‐terminal sequencing and mass spectrometry. About 16% of these proteins are of unknown function and three proteins have no orthologue in the nonpathogenic L. innocua and might be involved in virulence mechanisms. Remarkably, a relatively high number of proteins with a function in the cytoplasmic compartment was identified in this surface proteome. These proteins had neither predicted or detectable signal peptides nor could any modification be observed except removal of the N‐terminal methionine. Enolase (Lmo2455) is one of these proteins. It was shown to be present in the cell wall of the pathogen by immunoelectron microscopy and, along with heat shock factor DnaK (Lmo1473), elongation factor TU (Lmo2653), and glyceraldehyde‐3‐phosphate dehydrogenase (Lmo2459), it was found to be able to bind human plasminogen in overlay blots and surface plasmon resonance (SPR) experiments. The KD values of these interactions were determined by SPR measurements. The data indicate a possible role of these proteins as receptors for human plasminogen on the bacterial cell surface. The potential role of this recruitment of a host protease for extracellular invasion mechanisms is discussed.
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