Transient Binding Dynamics of Complement System Pattern Recognition Molecules on Pathogens.

Previous studies of pattern recognition molecules (PRMs) of the complement system have revealed difficulties in observing binding on pathogens such as Aspergillus fumigatus and Escherichia coli, despite complement deposition indicative of classical and lectin pathway activation. Thus, we investigated the binding dynamics of PRMs of the complement system, specifically C1q of the classical pathway and mannose-binding lectin (MBL) of the lectin pathway. We observed consistently increasing deposition of essential complement components such as C4b, C3b, and the terminal complement complex on A. fumigatus and E. coli. However, C1q and MBL binding to the surface rapidly declined during incubation after just 2-4 min in 10% plasma. The detachment of C1q and MBL can be linked to complement cascade activation, as the PRMs remain bound in the absence of plasma. The dissociation and the fate of C1q and MBL seem to have different mechanistic functions. Notably, C1q dynamics were associated with local C1 complex activation. When C1s was inhibited in plasma, C1q binding not only remained high but further increased over time. In contrast, MBL binding was inversely correlated with total and early complement activation due to MBL binding being partially retained by complement inhibition. Results indicate that detached MBL might be able to functionally rebind to A. fumigatus. In conclusion, these results reveal a (to our knowledge) novel "hit-and-run" complement-dependent PRM dynamic mechanism on pathogens. These dynamics may have profound implications for host defense and may help increase the functionality and longevity of complement-dependent PRMs in circulation.

Evaluation of 3-Deoxy-D-Arabino-Heptulosonate 7-Phosphate Synthase (DAHPS) as a Vulnerable Target in Mycobacterium tuberculosis.

Tuberculosis (TB) remains one of the leading causes of death due to a single pathogen. The emergence and proliferation of multidrug-resistant (MDR-TB) and extensively drug-resistant strains (XDR-TB) represent compelling reasons to invest in the pursuit of new anti-TB agents. The shikimate pathway, responsible for chorismate biosynthesis, which is a precursor of important aromatic compounds, is required for Mycobacterium tuberculosis growth. The enzyme 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase (MtbDAHPS) catalyzes the first step in the shikimate pathway and it is an attractive target for anti-tubercular agents. Here, we used a CRISPRi system to evaluate the DAHPS as a vulnerable target in M. tuberculosis. The silencing of aroG significantly reduces the M. tuberculosis growth in both rich medium and, especially, in infected murine macrophages. The supplementation with amino acids was only able to partially rescue the growth of bacilli, whereas the Aro supplement (aromix) was enough to sustain the bacterial growth at lower rates. This study shows that MtbDAHPS protein is vulnerable and, therefore, an attractive target to develop new anti-TB agents. In addition, the study contributes to a better understanding of the biosynthesis of aromatic compounds and the bacillus physiology. IMPORTANCE Determining the vulnerability of a potential target allows us to assess whether its partial inhibition will impact bacterial growth. Here, we evaluated the vulnerability of the enzyme 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase (DAHPS) from M. tuberculosis by silencing the DAHPS-coding aroG gene in different contexts. These results could lead to the development of novel and potent anti-tubercular agents in the near future.

EPSP Synthase-Depleted Cells Are Aromatic Amino Acid Auxotrophs in Mycobacterium smegmatis.

The epidemiological importance of mycobacterial species is indisputable, and the necessity to find new molecules that can inhibit their growth is urgent. The shikimate pathway, required for the synthesis of important bacterial metabolites, represents a set of targets for inhibitors of Mycobacterium tuberculosis growth. The aroA-encoded 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) enzyme catalyzes the sixth step of the shikimate pathway. In this study, we combined gene disruption, gene knockdown, point mutations (D61W, R134A, E321N), and kinetic analysis to evaluate aroA gene essentiality and vulnerability of its protein product, EPSPS, from Mycolicibacterium (Mycobacterium) smegmatis (MsEPSPS). We demonstrate that aroA-deficient cells are auxotrophic for aromatic amino acids (AroAAs) and that the growth impairment observed for aroA-knockdown cells grown on defined medium can be rescued by AroAA supplementation. We also evaluated the essentiality of selected MsEPSPS residues in bacterial cells grown without AroAA supplementation. We found that the catalytic residues R134 and E321 are essential, while D61, presumably important for protein dynamics and suggested to have an indirect role in catalysis, is not essential under the growth conditions evaluated. We have also determined the catalytic efficiencies (Kcat/Km) of recombinant wild-type (WT) and mutated versions of MsEPSPS (D61W, R134A, E321N). Our results suggest that drug development efforts toward EPSPS inhibition may be ineffective if bacilli have access to external sources of AroAAs in the context of infection, which should be evaluated further. In the absence of AroAA supplementation, aroA from M. smegmatis is essential, its essentiality is dependent on MsEPSPS activity, and MsEPSPS is vulnerable. IMPORTANCE We found that cells from Mycobacterium smegmatis, a model organism safer and easier to study than the disease-causing mycobacterial species, when depleted of an enzyme from the shikimate pathway, are auxotrophic for the three aromatic amino acids (AroAAs) that serve as building blocks of cellular proteins: l-tryptophan, l-phenylalanine, and l-tyrosine. That supplementation with only AroAAs is sufficient to rescue viable cells with the shikimate pathway inactivated was unexpected, since this pathway produces an end product, chorismate, that is the starting compound of essential pathways other than the ones that produce AroAAs. The depleted enzyme, the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), catalyzes the sixth step of shikimate pathway. Depletion of this enzyme inside cells was performed by disrupting or silencing the EPSPS-encoding aroA gene. Finally, we evaluated the essentiality of specific residues from EPSPS that are important for its catalytic activity, determined with experiments of enzyme kinetics using recombinant EPSPS mutants.

Effect of citric acid on the proteolytic activity of Zea mays L. / Efeito do ácido cítrico sobre a atividade proteolítica de Zea mays L.

Hybrids of Zea mays L. (Buffalo, Falcon, H360 y HV313) were treated with citric acid (2000 ppm). Grain yield, soluble protein and proteolytic activity were monitored when the crop reached physiological maturity. Citric acid was applied before the appearance of the flag leaf, and induced an increase in the grain yield from 4222 to 5780 kg/ha, in the soluble protein from 6.34 to 7.91 mg/mg and into the proteolytic activity from 14.3 to 65.7 µU mg prot-1. This is an increase of 2 to 12 times in the Falcon, H360 and HV313 hybrids, while the Buffalo hybrid responded with less intensity to the treatment with citric acid. In the H360 hybrid treated with citric acid, an increase in the proteolytic activity of aspartyl serine proteases was observed. The results indicate that citric acid differentially induces proteolytic activity and vigor in the corn hybrids analyzed.

Zea mays L. híbridos (Buffalo, Falcão, H360 e HV313) foram tratados com ácido cítrico (2000 ppm). O rendimento de grãos, proteína solúvel e atividade proteolítica foram monitorados na fase de maturação fisiológica do cultivo. O ácido cítrico aplicado antes do aparecimento da folha bandeira induziu um aumento na produção de grãos 4222 a 5780 kg/ha, na proteína solúvel de 6.34 7.91 mg/mg de peso seco e atividade proteolítica de 14.3 to 65.7 µU mg prot-1, esto é, um incremento de 2-12 vezes nos híbridos Falcao, H360 e HV313, enquanto o híbrido Buffalo responderam com menor intensidade ao tratamento com ácido cítrico. No híbrido H360, tratadas com ácido cítrico, apresentou-se um aumento na atividade proteolítica de aspartil proteases e serin protease. Os resultados indicam que o ácido cítrico diferencialmente induz a atividade proteolítica e o vigor de híbridos de milho testados.

Angiosarcoma of the nasal cavity: a case report.

Angiosarcomas are malignant neoplasias of rapid growth that develop from endothelial cells. They represent 2% of all sarcomas and only 1-4% are located in the aerodigestive tract. Since 1977, only 16 cases have been reported.We present a 33-year-old male with spontaneous epistaxis that was refractory to cauterization. During physical examination, a smooth purplish tumor of 1.5 cm x 1.5 cm was identified. A CT scan showed a nonenhanced tumor in the left nostril on the uncinate process. A biopsy revealed an intermediate-grade angiosarcoma. Surgical removal followed by radiation therapy was performed with good result. Aerodigestive angiosarcomas have a better prognosis than angiosarcomas of other locations due to better cell differentiation and the presence of early symptoms. Recurrence can occur because of tumor tissue left during resection. Our patient continues tumor free after three years.

Salud mental de los trabajadores de la Dirección de Educación de la Municipalidad de Concepción / Mental health of workers of the Dirección de Educación, Municipalidad de Concepción

En el contexto del Programa de Epidemiología Psiquiátrica para Chile, se presentan los resultados del estudio de prevalencia de algunos trastornos psiquiátricos en los trabajadores de la Dirección de Educación de la Municipalidad de Concepción. A una muestra de 242 trabajadores representativa de las tres categorías laborales existentes (directores, docentes, administrativos) se les aplicó el CIDI 1.1, junto a un conjunto de otros instrumentos. Se destaca una prevalencia de vida según criterios CIE-10 de un 49.5 por ciento y una prevalencia de seis meses de un 23.45 por ciento. Las prevalencias son analizadas por las variables sociodemográficas usuales y se comparan referencialmente con las de otros estudios. Se concluye que es un grupo de alto riesgo que requiere intervención preferentemente preventiva

Prevalencia de algunos trastornos psiquiátricos en los trabajadores de la salud dependientes de la Dirección de Administración de Salud de la Municipalidad de Concepción / Prevalence of some psychiatric disorders in the health workers of Dirección de Administración de Salud, Municipalidad de Concepción

Se presentan los resultados de un estudio de prevalencia de algunos trastornos psiquiátricos en los funcionarios de la Dirección de Salud de la Municipalidad de Concepción. A un total de 122 personas, aproximadamente un tercio de total, se les aplicó el composite diagnostic interview (CIDI) por entrevistadores legos previamente capacitados. La prevalencia encontrada según criterios DSM-III-R se presentan y analizan según variables sociodemográficos. Destaca una prevalencia de vida de un 42.9 por ciento a expensas principalmente de los cuadros fobicos. La prevalencia de 6 meses llega a un 17,5 por ciento cuando los resultados se comparan con otros similares encontrados en poblaciones específicas muy parecidas se concluye que, poco o nada ha cambiado en la ultima década

Clima organizacional en dos grupos laborales de la Municipalidad de Concepción / Organizational enviroment in 2 labor groups of the Municipalidad de Concepción

Se intenta evaluar la percepción que tienen los funcionarios de salud y educación de la Municipalidad de Concepción, respecto del clima laboral de la organización a la que pertenecen, analizando los resultados por variables sociodemográficas, laborales y de presencia de patología psíquica. A una muestra aleatoria de 364 sujetos, funcionarios de 6 establecimientos de atención primaria en salud y de 63 establecimientos educacionales, todos de administración municipal, se aplicó el cuestionario de clima organización de Litwin y Stringer, previamente adaptado, la entrevista diagnóstica estructurada CIDI y el cuestionario Graffar para determinación del nivel socioeconómico. Los datos fueron procesados con el SPSS, en base a medianas. Las tasa de respuesta alcanzó al 82,7 por ciento. Los resultados para el total e la muestra (n=301) señalan diferencias estadísticamente significativas en las dimensiones apoyo en función del género; y estructura, y manejo de conflictos en función de la presencia/ausencia de patología psíquica; manejo de conflictos en función del nivel socioeconómico; estructura recompensa, riesgo, calidez e identidad en función del establecimiento de pertenencia; y responsabilidad, rendimiento y manejo de conflictos en función de la categoría laboral. En el sector salud (n=91) diferencias estadísticamente significativas se presentan en las dimensiones calidez en función de la edad; responsabilidad en función diagnóstico psiquiátrico; y riesgo e identidad en función del establecimiento laboral. Se concluye que la dimensión más débil, para todos los casos, es la identificación con la organización. En el sector salud la percepción del manejo de conflictos está por sobre el total de la muestra y del sector educación

Factores asociados a trastornos psiquiátricos en los trabajadores de la educación y salud de la Municipalidad de Concepción / Associated factors to psychiatric disorders in education and health workers of the Municipalidad de Concepción

Se presenta el análisis de algunos factores que pudieran estar asociados a las prevalencias de trastornos psiquiátricos en dos grupos laborales. Se constata una mayor prevalencia de trastornos psiquiátricos en el sector salud educación comparado con el de salud con el consecuente mayor uso de servicios. Destacó el alto nivel de satisfacción con la atención recibida. Se analizan otras variables sin encontrar elementos diferenciales significativos

Efectos en salud de la contaminación de las aguas del sistema Río Maipo-Mapocho

Señala los orígenes de los contaminantes presentes en las aguas residuales que se utilizan para riego en la Región Metropolitana de Chile. Indica las vias y formas de exposición humana a los riesgos que implica este problema. Resume la experiencia sobre efectos conocidos en la salud de la población, indicando algunos datos estadísticos