Recombinant Listeria monocytogenes expressing a cell wall-associated listeriolysin O is weakly virulent but immunogenic

Listeriolysin O (LLO) is an essential virulence factor for the gram-positive bacterium Listeria monocytogenes. Our goal was to determine if altering the topology of LLO would alter the virulence and toxicity of L. monocytogenes in vivo. A recombinant strain was generated that expressed a surface-associated LLO (sLLO) variant secreted at 40-fold-lower levels than the wild type. In culture, the sLLO strain grew in macrophages, translocated to the cytosol, and induced cell death. However, the sLLO strain showed decreased infectivity, reduced lymphocyte apoptosis, and decreased virulence despite a normal in vitro phenotype. Thus, the topology of LLO in L. monocytogenes was a factor in the pathogenesis of the infection and points to a role of LLO secretion during in vivo infection. The sLLO strain was cleared by severe combined immunodeficient (SCID) mice. Despite the attenuation of virulence, the sLLO strain was immunogenic and capable of eliciting protec-tive T-cell responses. Listeria monocytogenes is a gram-positive facultative intra-cellular pathogen extensively used to understand host-patho-gen interactions (44, 51, 53). It expresses the highly conserved pore-forming toxin listeriolysin O (LLO), a member of a large family of cholesterol-dependent cytolysins found in many im

Resonant Magnetic Vortices

By using the complex angular momentum method, we provide a semiclassical analysis of electron scattering by a magnetic vortex of Aharonov-Bohm-type. Regge poles of the $S$-matrix are associated with surface waves orbiting around the vortex and supported by a magnetic field discontinuity. Rapid variations of sharp characteristic shapes can be observed on scattering cross sections. They correspond to quasibound states which are Breit-Wigner-type resonances associated with surface waves and which can be considered as quantum analogues of acoustic whispering-gallery modes. Such a resonant magnetic vortex could provide a new kind of artificial atom while the semiclassical approach developed here could be profitably extended in various areas of the physics of vortices.Comment: 6 pages, 7 figure

A proteomic focus of the alterations occurring at the human atherosclerotic coronary intima and media

Comunicaciones a congreso

Ullucus tuberosus Caldas: colección de germoplasma de ullucu conservada en el Centro Internacional de la Papa (CIP).

El presente catálogo contiene información pasaporte, datos de caracterización morfológica y ploidía para 432 accesiones de ulluco mantenidas en el banco de germoplasma del CIP. Para ilustrar mejor los datos de caracterización morfológica, cada accesión está acompañada de un set de fotografías que incluye la parte aérea de la planta, los tubérculos, las flores y una muestra lista para herborizar conformada por un tallo con sus hojas y flores. La información pasaporte es complementada con mapas ilustrados que muestran el lugar de colecta de cada accesión

Proteomic analysis of intimal layer from human coronary atherothrombotic arteries

Comunicaciones a congreso

Identification of protein expressed by aortic stenosis valves in the search for novel biomarkers

Comunicaciones a congreso

Nonlinear Aharonov-Bohm scattering by optical vortices

We study linear and nonlinear wave scattering by an optical vortex in a self-defocusing nonlinear Kerr medium. In the linear case, we find a splitting of a plane-wave front at the vortex proportional to its circulation, similar to what occurs in the scattered wave of electrons for the Aharonov-Bohm effect. For larger wave amplitudes, we study analytically and numerically the scattering of a dark-soliton stripe (a nonlinear analog of a small-amplitude wavepacket) by a vortex and observe a significant asymmetry of the scattered wave. Subsequently, a wavefront splitting of the scattered wave develops into transverse modulational instability, ``unzipping'' the stripe into trains of vortices with opposite charges.Comment: 4 pages, 4 figure