The proteins DotY and DotZ modulate the dynamics and localization of the type IVB coupling complex of Legionella pneumophila

Legionella pneumophila is an opportunistic pathogen infecting alveolar macrophages and protozoa species. Legionella utilizes a Type IV Secretion System (T4SS) to translocate over 300 effector proteins into its host cell. In a recent study, we isolated and solved the cryo-EM structure of the Type IV Coupling Complex (T4CC), a large cytoplasmic determinant associated with the inner membrane that recruits effector proteins for delivery to the T4SS for translocation. The T4CC is composed of a DotLMNYZ hetero-pentameric core from which the flexible IcmSW module flexibly protrudes. The DotY and DotZ proteins were newly reported members of this complex and their role remained elusive. In this study, we observed the effect of deleting DotY and DotZ on T4CC stability and localization. Furthermore, we found these two proteins are co-dependent, whereby the deletion of DotY resulted in DotZ absence from the coupling complex, and vice versa. Additional cryo-EM data analysis revealed the dynamic movement of the IcmSW module is modified by the DotY/Z proteins. We therefore determined the likely function of DotY and DotZ and revealed their importance on T4CC function

Mechanism of effector capture and delivery by the type IV secretion system from Legionella pneumophila

Legionella pneumophila is a bacterial pathogen that utilises a Type IV secretion (T4S) system to inject effector proteins into human macrophages. Essential to the recruitment and delivery of effectors to the T4S machinery is the membrane-embedded T4 coupling complex (T4CC). Here, we purify an intact T4CC from the Legionella membrane. It contains the DotL ATPase, the DotM and DotN proteins, the chaperone module IcmSW, and two previously uncharacterised proteins, DotY and DotZ. The atomic resolution structure reveals a DotLMNYZ hetero-pentameric core from which the flexible IcmSW module protrudes. Six of these hetero-pentameric complexes may assemble into a 1.6-MDa hexameric nanomachine, forming an inner membrane channel for effectors to pass through. Analysis of multiple cryo EM maps, further modelling and mutagenesis provide working models for the mechanism for binding and delivery of two essential classes of Legionella effectors, depending on IcmSW or DotM, respectively

Structural and functional characterization of Pseudomonas aeruginosa CupB chaperones

Pseudomonas aeruginosa, an important human pathogen, is estimated to be responsible for,10% of nosocomial infections worldwide. The pathogenesis of P. aeruginosa starts from its colonization in the damaged tissue or medical devices (e. g. catheters, prothesis and implanted heart valve etc.) facilitated by several extracellular adhesive factors including fimbrial pili. Several clusters containing fimbrial genes have been previously identified on the P. aeruginosa chromosome and named cup [1]. The assembly of the CupB pili is thought to be coordinated by two chaperones, CupB2 and CupB4. However, due to the lack of structural and biochemical data, their chaperone activities remain speculative. In this study, we report the 2.5 A crystal structure of P. aeruginosa CupB2. Based on the structure, we further tested the binding specificity of CupB2 and CupB4 towards CupB1 (the presumed major pilus subunit) and CupB6 (the putative adhesin) using limited trypsin digestion and strep-tactin pull-down assay. The structural and biochemical data suggest that CupB2 and CupB4 might play different, but not redundant, roles in CupB secretion. CupB2 is likely to be the chaperone of CupB1, and CupB4 could be the chaperone of CupB4:CupB5:CupB6, in which the interaction of CupB4 and CupB6 might be mediated via CupB5

Taxonomy and chemical characterization of new antibiotics produced by Saccharothrix SA198 isolated from a Saharan soil

Actinomycete strain SA198, isolated from a Saharan soil sample of Algeria, exhibited antimicrobial activity against Gram-positive and Gram-negative bacteria, and phytopathogenic and toxinogenic fungi. The morphological and chemotaxonomic characteristics of the strain were consistent with those of the genus Saccharothrix. Analysis of the 16S rRNA gene sequence of strain SA198 showed a similarity level ranging between 97.2 and 98.8% within Saccharothrix species, S. australiensis being the most closely related. Two new active products were isolated by reverse HPLC using a C18 column. The ultraviolet–visible (UV–VIS), infrared (IR), mass, and 1Hand 14C nuclear magnetic resonance (NMR) spectra showed that these products were new bioactive compounds. The minimum inhibitory concentrations of these antibiotics showed a strong activity against fungi and moderate activities against Gram-positive and Gram-negative bacteria

Desarrollo y evaluación mecánica de cubiertas poliméricas a base de nanocápsulas cargadas con aceite esencial de Thymus vulgaris.

A nivel mundial se estima que las pérdidas postcosecha de frutas y hortalizas frescas oscilan entre 15 y 85%. En los últimos años se han investigado las propiedades y aplicaciones del uso de recubrimientos y películas que mantengan la calidad de los alimentos y prolonguen la vida útil de estos. El aceite esencial de Thymus vulgaris han sido utilizado en cubiertas poliméricas por su actividad antibacteriana, sin embargo debido a su gran volatilidad, su uso se ha visto limitado por lo que es necesario su nanoencapsulación. Las NC obtenidas por la técnica de nanoprecipitación, fueron homogéneas y estables y se utilizaron para formar las cubiertas. Estas cubiertas fueron transparentes, homogéneas y resistentes al doblez. En base a sus propiedades mecánicas, se demostró que, las cubiertas formadas a base de NC, presentan un bajo porcentaje de elongación y rompimiento pero una adhesión elevada. Las cubiertas poliméricas obtenidas a base de NC cargadas con el aceite esencial de Thymus vulgaris, tienen un gran potencial como recubrimiento de frutas y hortalizas

Guillain-Barré syndrome: a century of progress

In 1916, Guillain, Barré and Strohl reported on two cases of acute flaccid paralysis with high cerebrospinal fluid protein levels and normal cell counts — novel findings that identified the disease we now know as Guillain–Barré syndrome (GBS). 100 years on, we have made great progress with the clinical and pathological characterization of GBS. Early clinicopathological and animal studies indicated that GBS was an immune-mediated demyelinating disorder, and that severe GBS could result in secondary axonal injury; the current treatments of plasma exchange and intravenous immunoglobulin, which were developed in the 1980s, are based on this premise. Subsequent work has, however, shown that primary axonal injury can be the underlying disease. The association of Campylobacter jejuni strains has led to confirmation that anti-ganglioside antibodies are pathogenic and that axonal GBS involves an antibody and complement-mediated disruption of nodes of Ranvier, neuromuscular junctions and other neuronal and glial membranes. Now, ongoing clinical trials of the complement inhibitor eculizumab are the first targeted immunotherapy in GBS

CRT-100.12 Risk of Bleeding Among Cangrelor-Treated Patients Administered Upstream P2Y12 Inhibitor Therapy

Introduction: Little is known about the use of cangrelor in patients with MI who are treated with an oral P2Y12 inhibitor upstream prior to cardiac catheterization. Methods: CAMEO (Cangrelor in Acute MI: Effectiveness and Outcomes) is a 12-hospital observational registry studying platelet inhibition for MI patients undergoing cardiac cath. Upstream oral P2Y12 inhibition was defined as receipt of an oral P2Y12 inhibitor within 24 hours prior to hospitalization or in-hospital prior to cath. Among cangrelor-treated patients, we compared bleeding after cangrelor use through 7 days post-discharge between patients with and w/o upstream oral P2Y12 inhibitor exposure using logistic regression. We examined rates of bleeding among patients with a shorter (\u3c1 hour) vs. longer (1-3 hours or \u3e3 hours) duration between the last oral dose and cangrelor start. Results: Among 1,775 cangrelor-treated MI patients, 433 (24.4%) had upstream oral P2Y12 inhibitor treatment prior to cath. Of these, 165 patients (38%) started cangrelor within 1 hour, 109 (25%) between 1-3 hours, and 134 (31%) \u3e 3 hours after the in-hospital oral P2Y12 inhibitor dose. Cangrelor-treated patients who received upstream treatment were more likely to have a history of prior PCI, MI, PAD, and diabetes and to be clopidogrel-treated (all p\u3c0.01) compared w/o upstream treatment. There was no significant difference in risk of bleeding among cangrelor-treated patients with and w/o upstream oral P2Y12 inhibitor exposure (Table). While bleeding events were higher in patients with longer delays to cangrelor initiation, bleeding risk was not significant after adjustment (Table). Conclusions: Bleeding risk was not observed to be higher in cangrelor-treated patients after upstream oral P2Y12 inhibitor exposure compared with patients treated with cangrelor w/o upstream oral P2Y12 inhibitor exposure

Desarrollo e implementación de una herramienta para revisión y recodificación de datos de pacientes internados

La necesidad de información para la toma de decisiones de gestión eficiente en una institución de salud es de innegable importancia. Para la gestión oportuna y adecuada de los indicadores de internación y la toma de acciones sobre los mismos es necesario contar con información de calidad. Se generó una herramienta de post procesamiento de datos asistenciales de internación tendiente a lograr completitud en los registros y homogeneidad en los mismos para secundariamente construir indicadores de mejor calidad para alimentar los tableros de mando informatizados de los tomadores de decisiones asistenciales y de gestión administrativa. Luego de un piloto de un mes se comenzó a trabajar durante todo el 2014 y se procesaron los datos provenientes de las internaciones de ese año lográndose una recodificación y mapeo total de estos episodios en una base de datos ad hoc. El proceso y el aplicativo con el que se llevó a cabo el proceso se denominó Back Office de Internación (BO). Los resultados fueron muy bien recibidos por dichos decisores y estamos en plan de aumentar la cantidad de información procesada, mejorar su calidad de interoperabilidad y comenzar una retroalimentación con los actores de salud encargados de registrar los datos que conforman el crudo de BO con el objetivo de generar cambios de calidad en la estandarización de los mencionados registros.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Desarrollo e implementación de una herramienta para revisión y recodificación de datos de pacientes internados

La necesidad de información para la toma de decisiones de gestión eficiente en una institución de salud es de innegable importancia. Para la gestión oportuna y adecuada de los indicadores de internación y la toma de acciones sobre los mismos es necesario contar con información de calidad. Se generó una herramienta de post procesamiento de datos asistenciales de internación tendiente a lograr completitud en los registros y homogeneidad en los mismos para secundariamente construir indicadores de mejor calidad para alimentar los tableros de mando informatizados de los tomadores de decisiones asistenciales y de gestión administrativa. Luego de un piloto de un mes se comenzó a trabajar durante todo el 2014 y se procesaron los datos provenientes de las internaciones de ese año lográndose una recodificación y mapeo total de estos episodios en una base de datos ad hoc. El proceso y el aplicativo con el que se llevó a cabo el proceso se denominó Back Office de Internación (BO). Los resultados fueron muy bien recibidos por dichos decisores y estamos en plan de aumentar la cantidad de información procesada, mejorar su calidad de interoperabilidad y comenzar una retroalimentación con los actores de salud encargados de registrar los datos que conforman el crudo de BO con el objetivo de generar cambios de calidad en la estandarización de los mencionados registros.Sociedad Argentina de Informática e Investigación Operativa (SADIO