Defining the remarkable structural malleability of a bacterial surface protein Rib domain implicated in infection

Streptococcus groups A and B cause serious infections, including early onset sepsis and meningitis in newborns. Rib domain-containing surface proteins are found associated with invasive strains and elicit protective immunity in animal models. Yet, despite their apparent importance in infection, the structure of the Rib domain was previously unknown. Structures of single Rib domains of differing length reveal a rare case of domain atrophy through deletion of 2 core antiparallel strands, resulting in the loss of an entire sheet of the β-sandwich from an immunoglobulin-like fold. Previously, observed variation in the number of Rib domains within these bacterial cell wall-attached proteins has been suggested as a mechanism of immune evasion. Here, the structure of tandem domains, combined with molecular dynamics simulations and small angle X-ray scattering, suggests that variability in Rib domain number would result in differential projection of an N-terminal host-colonization domain from the bacterial surface. The identification of 2 further structures where the typical B-D-E immunoglobulin β-sheet is replaced with an α-helix further confirms the extensive structural malleability of the Rib domain

Structure and mechanism of a bacterial beta-glucosaminidase having O-GlcNAcase activity

O-GlcNAc is an abundant post-translational modification of serine and threonine residues of nucleocytoplasmic proteins. This modification, found only within higher eukaryotes, is a dynamic modification that is often reciprocal to phosphorylation. In a manner analogous to phosphatases, a glycoside hydrolase termed O-GlcNAcase cleaves O-GlcNAc from modified proteins. Enzymes with high sequence similarity to human O-GlcNAcase are also found in human pathogens and symbionts. We report the three-dimensional structure of O-GlcNAcase from the human gut symbiont Bacteroides thetaiotaomicron both in its native form and in complex with a mimic of the reaction intermediate. Mutagenesis and kinetics studies show that the bacterial enzyme, very similarly to its human counterpart, operates via an unusual 'substrate-assisted' catalytic mechanism, which will inform the rational design of enzyme inhibitors

Afferent and Efferent Connections of the Sexually Dimorphic Medial Preoptic Nucleus of the Male Quail Revealed by in Vitro Transport of Dii

The medial preoptic nucleus of the Japanese quail is a testosterone-sensitive structure that is involved in the control of male copulatory behavior. The full understanding of the role played by this nucleus in the control of reproduction requires the identification of its afferent and efferent connections. In order to identify neural circuits involved in the control of the medial preoptic nucleus, we used the lipophilic fluorescent tracer DiI implanted in aldheyde-fixed tissue. Different strategies of brain dissection and different implantation sites were used to establish and confirm afferent and efferent connections of the nucleus. Anterograde projections reached the tuberal hypothalamus, the area ventralis of Tsai, and the substantia grisea centralis. Dense networks of fluorescent fibers were also seen in several hypothalamic nuclei, such as the anterior medialis hypothalami, the paraventricularis magnocellularis, and the ventromedialis hypothalami. A major projection in the dorsal direction was also observed from the medial preoptic nucleus toward the nucleus septalis lateralis and medialis. Afferents to the nucleus were seen from all these regions. Implantation of DiI into the substantia grisea centralis also revealed massive bidirectional connections with a large number of more caudal mesencephalic and pontine structures. The substantia grisea centralis therefore appears to be an important center connecting anterior levels of the brain to brain-stem nuclei that may be involved in the control of male copulatory behavior

Efectividad de una guía de diagnósticos de enfermería para el registro en pacientes con cardiopatias lima 2014

Los registros de enfermería son actualmente más importantes que nunca, debido al aumento de las situaciones médico-legales, frente a las cuales es indispensable contar con un respaldo del trabajo realizado, respaldo que, idealmente, debe favorecer la comunicación entre los componentes del equipo de salud; utilizando un lenguaje estandarizado al momento de registrar las acciones en las notas de enfermería. Es por ello la importancia de este estudio, que tiene como objetivo Determinar la efectividad de una guía de diagnósticos de enfermería para el registro en pacientes con cardiopatías, aplicado a los enfermeros del servicio de tórax y cardiovascular del Instituto Nacional de Salud del Niño. El presente estudio es de tipo cuantitativo, nivel aplicativo, de corte transversal y utiliza el método cuasiexperimental. La población estuvo conformada por 13 enfermeros asistenciales del servicio y la unidad de análisis la conformaron las notas de enfermería registradas en las historias clínicas de los pacientes con cardiopatías del Servicio de Cirugía de Tórax y Cardiovascular. Las técnicas utilizadas fueron la observación y una encuesta, y los instrumentos una Guía de Diagnósticos de Enfermería y una Escala de Likert Modificada. Los resultados encontrados revelan que la guía de diagnósticos de enfermería es efectiva dado que sus 4 dimensiones fueron registrados en un 82.41% en las notas de enfermería, y los enfermeros estuvieron de acuerdo en su utilización en el servicio según la encuesta de opinión aplicada, con lo cual se aceptan la hipótesis de estudio.Tesi