Solution X-ray scattering study of a full-length class A penicillin-binding protein.

Penicillin binding proteins (PBPs) catalyze essential steps in the biosynthesis of peptidoglycan, the main component of the bacterial cell wall. PBPs can harbor two catalytic domains, namely the glycosyltransferase (GT) and transpeptidase (TP) activities, the latter being the target for ß-lactam antibiotics. Despite the availability of structural information regarding bi-functional PBPs, little is known regarding the interaction and flexibility between the TP and GT domains. Here, we describe the structural characterization in solution by small angle X-ray scattering (SAXS) of PBP1b, a bi-functional PBP from Streptococcus pneumoniae. The molecule is present in solution as an elongated monomer. Refinement of internal coordinates starting from a homology model yields models in which the two domains are in an extended conformation without any mutual contact compatible with the existence of restricted mobility.

Patologías mamarias más frecuentes y su relación con la edad / Age distribution of breast diseases (neoplasm, fibroadenoma, fibrocystic disease and others)

Se estudian 784 casos de biopsias de glándula mamaria en mujeres, realizando una correlación entre la edad de las pacientes y el diagnóstico. Las patologías encontradas en las mujeres menores de 50 años muestran una marcada tendencia a la benignidad, en cambio hay un notable incremento de patologías malignas en pacientes con más de 50 años, lo que nos lleva a concluir que hay una correlación directa entre edad y el tipo de patología mamaria que se presenta