RESUMEN
Borrelia burgdorferi conserved gene products BB0406 and BB0405, members of a common B. burgdorferi paralogous gene family, share 59% similarity. Although both gene products can function as potential porins, only BB0405 is essential for infection. Here we show that, despite sequence homology and coexpression from the same operon, both proteins differ in their membrane localization attributes, antibody accessibility, and immunogenicity in mice. BB0406 is required for spirochete survival in mammalian hosts, particularly for the disseminated infection in distant organs. We identified that BB0406 interacts with laminin, one of the major constituents of the vascular basement membrane, and facilitates spirochete transmigration across host endothelial cell barriers. A better understanding of how B. burgdorferi transmigrates through dermal and tissue vascular barriers and establishes disseminated infections will contribute to the development of novel therapeutics to combat early infection.
Asunto(s)
Proteínas de la Membrana Bacteriana Externa/inmunología , Células Endoteliales/microbiología , Interacciones Huésped-Patógeno , Laminina/metabolismo , Enfermedad de Lyme/microbiología , Animales , Anticuerpos Antibacterianos/inmunología , Antígenos Bacterianos/inmunología , Proteínas de la Membrana Bacteriana Externa/genética , Borrelia burgdorferi/efectos de los fármacos , Borrelia burgdorferi/genética , Modelos Animales de Enfermedad , Células Endoteliales/metabolismo , Expresión Génica , Marcación de Gen , Prueba de Complementación Genética , Humanos , Ratones , Ratones Endogámicos C3H , Mutación , Unión ProteicaRESUMEN
This paper investigates the influence of non-uniform corrosion in the transversal direction of the steel reinforcement on the cracking propagation of the concrete cover. An analytical model is proposed for the prediction of the corrosion-induced cracking performance. Both the thick cylinder theory of the concrete and the effect of transversal non-uniform corrosion of the steel reinforcement are involved by considering the corrosion layer of the corrosion products and a layer of concrete with the corrosion products filled with the pores. A three-stage corrosion-induced cracking of the concrete is proposed: corrosion without expansive stress to the concrete, corrosion with expansive stress to the adjacent concrete, as well as the corrosion-induced cracking of the concrete. By considering the non-uniform corrosion of the steel reinforcement and the tensile stress induced by the volumetric expansion of the corrosion products, the cracking initiation resulting from the non-uniform corrosion was involved in the prediction model. The models were also validated by the experimental results from both the corroded specimens and the existing literature, which would be helpful for the evaluation of the existing reinforced concrete constructions in the marine environment.