Pneumococcal biofilms

Over 60% of bacterial infections (and up to 80% of chronic infections) are currently considered to involve microbial growth in biofilms. This peculiar form of life poses an array of problems in human clinical practice, from infections associated with the implant of prosthetic devices and dental plaque formation to diseases such as cystic fibrosis, otitis media, and endocarditis. Biofilms are also at the basis of a variety of problems in industry. This report describes the biofilms produced by Streptococcus pneumoniae. This bacterium often colonizes the upper airways in humans as a normal commensal, yet it may spread to other areas of the body, causing otitis media, pneumonia, or invasive diseases such as bacteremia and meningitis. The capacity of S. pneumoniae to form biofilms had not been explored until recently. Several newly developed in vitro systems have allowed to test the capacity of S. pneumoniae to form biofilms, and to analyze the influence of several factors, including DNA and proteins—which play a role in the virulence of this “supergerm” in the formation and development of biofilms. In this brief review, we update the knowledge available on pneumococcal biofilm formation and the unusual features of this structure

Interacción entre la proteína RepB y el origen de replicación de pLS1

Se hah estudiado las interacciones entre la proteína iniciadora de la replicacion, repb y el origen de replicacion (dso) del plasmido pls1. Este plásmico replica por el mecanismo de circulo rodante asimétrico. Se ha delimitado el dso en un fragmento de 247 pb. Se compone de dos regiones separadas fisica y funcionalmente: bind, constituida por tres repeticiones directas de 11pb y 8iterones) nic, formada pro dos estructuras palindromicas, las horquillas i y ii. Repb se une a los tres iterones e introduce un corte en el lazo monocatenario de la h-i a 84 pb del primer iteron. Repb reconoce la secuencia consenso: 5'tactacgac-3', e introduce un corte del enlace fosfodiester entre los nt g y a. Repb posee actividades de endonucleasa especifica de sitio y hebra y nucleotidiltransferasa. Su actividad es independiente de orientación, y dependiente de la temperatura. Actura sobre dna superenrollado siendo importante el grado de suprenrollamiento y sobre ssdna: no presenta actividad detectable sobre dsdna lineal. Pls1 es el prototipo de una familia de plasmidos que presentan homología en el dso y en sus proteinas rep. Repb presenta actividad, in vitro, sobre los orígenes de plasmidos de la familia. Por comparación de la secuencia de aa de las proteinas rep se han establecido 5 regiones conservadas: r-i, esencial para la replicacion in vivo; r-iii correspondería al motivo de unión a metales y en r-iv se encuentra el residuo tyr implicado en la reacción de corte y unión covalente al dna. Los motivos r-ii y r-v podrían formar parte del centro activo de la proteín

Implementación del marketing mix para mejorar el posicionamiento del minimarket T&P, San Martín de Porres, 2020

La presente investigación planteó como problema general ¿De qué manera la implementación del Marketing Mix influye en el posicionamiento del Minimarket T&P? teniendo como objetivo general, determinar la influencia de la implementación de Marketing Mix en el posicionamiento del Minimarket T&P. El estudio fue de nivel explicativo, enfoque cuantitativo, diseño cuasi experimental y de tipo aplicada. Por otro lado, la muestra fue de 383 clientes, aplicando la técnica de la encuesta, utilizando como instrumento, un cuestionario validado por 3 juicios de experto. Asimismo, en el informe se desarrollaron distintas actividades como la creación del logo, implementación de redes sociales, implementación del POS móvil, diagrama de flujo, Matriz Ansoff, estrategia de precio, definición del canal de distribución y estrategia de promociones. Los resultados al implementar el marketing mix fue, que mejoraron el posicionamiento de 91,5% nivel medio y 8,5% nivel alto a un nivel medio 33,4% y alto 66,6%. Asimismo, se utilizó el estadístico U de Mann-Withney y se pudo ver que la significancia de 0.000, fue menor al 0.05. Por lo tanto, se concluyó que la influencia de la implementación del Marketing Mix mejoró el posicionamiento del Minimarket T&

Biofilm formation avoids complement immunity and phagocytosis of Streptococcus pneumoniae

Streptococcus pneumoniae is a frequent member of the microbiota of the human nasopharynx. Colonization of the nasopharyngeal tract is a first and necessary step in the infectious process and often involves the formation of sessile microbial communities by this human pathogen. The ability to grow and persist as biofilms is an advantage for many microorganisms, because biofilm-grown bacteria show reduced susceptibility to antimicrobial agents and hinder recognition by the immune system. The extent of host protection against biofilm-related pneumococcal disease has not been determined yet. Using pneumococcal strains growing as planktonic cultures or as biofilms, we have investigated the recognition of S. pneumoniae by the complement system and its interactions with human neutrophils. Deposition of C3b, the key complement component, was impaired on S. pneumoniae biofilms. In addition, binding of C-reactive protein and the complement component C1q to the pneumococcal surface was reduced in biofilm bacteria, demonstrating that pneumococcal biofilms avoid the activation of the classical complement pathway. In addition, recruitment of factor H, the downregulator of the alternative pathway, was enhanced by S. pneumoniae growing as biofilms. Our results also show that biofilm formation diverts the alternative complement pathway activation by a PspC-mediated mechanism. Furthermore, phagocytosis of pneumococcal biofilms was also impaired. The present study confirms that biofilm formation in S. pneumoniae is an efficient means of evading both the classical and the PspC-dependent alternative complement pathways the host immune system.This work was supported by grants SAF2009-10824; and SAF2012-39444-C02-01/02 from Dirección General de Investigación Científica y Técnica and MINECO, respectively. Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES) is an initiative of the ISCIII. M.D. and E.R-S. were supported by FPI and FPU fellowships, respectively, from Ministerio de Economía y Competitividad.S

LytA is involved in the evasion of complement- mediated immunity and invasive disease by a pneumolysin-independent mechanism

2 p.Streptococcus pneumoniae is one of the major causes of invasive disease accounting for more deaths than any other vaccine-preventable bacterial infection. Recognition by the complement system is a vital event in the clearance of this important human pathogen. We show here that the main autolytic enzyme of the bacterium,the amidase LytA, avoid complement-mediated immunity by a complex mechanism of impaired activation and increased down-regulation. Moreover, we demonstrated that both ply and lytA mutants were attenuated in pneumonia and sepsis and the virulence of the double mutant was greatly impaired demonstrating that both proteins play an important role in the establishment of the pneumococcal invasive disease.Peer reviewe

A highly-safe live auxotrophic vaccine protecting against disease caused by non-typhoidal Salmonella Typhimurium in mice

Background: Salmonella enterica serovar Typhimurium (S. Typhimurium) has become an important intestinal pathogen worldwide and is responsible for lethal invasive infections in populations at risk. There is at present an unmet need for preventive vaccines. Methods: IRTA GN-3728 genome was sequenced by Illumina and D-glutamate and D-glutamate/D-alanine knockout-auxotrophs were constructed. They were characterized using electron microscopy, growth/viability curves, reversion analysis, and motility/agglutination assays. Their potential as vaccine candidates were explored using two BALB/c mouse models for Salmonella infections: a systemic and an intestinal inflammation. Clinical signs/body weight and survival were monitored, mucosal lactoferrin and specific/cross-reactive IgA/IgG were quantified by enzyme-linked-immunosorbent assays and bacterial shedding/burden in fecal/tissues were evaluated. Results: The D-glutamate auxotroph, IRTA DmurI, is highly attenuated, immunogenic and fully protective against systemic infection. The IRTA DmurI Dalr DdadX double auxotroph, constructed to reinforce vaccine safety, showed a higher level of attenuation and was 100% effective against systemic disease. In the intestinal model, it proved to be safe, yielding a lowdegree of mucosal inflammation, short-term shedding and undetectable invasiveness in the long-term, while eliciting cross-reactive fecal IgA/serum IgG against clinically relevant multidrug-resistant (MDR) S. Typhimurium strains. It also conferred protection against homologous oral challenge, and protected mice from local and extra-intestinal dissemination caused by one MDR strain responsible for an international outbreak of highly severe human infections. Additionally, oral vaccination promoted extended survival after lethal heterologous infection. Conclusion: This study yielded a very safe S. Typhimurium vaccine candidate that could be further refined for mucosal application against disease in humans.This study was supported by a grant from SERGAS (The Galician Healthcare Service) (Programs “InnovaSaude” and “InnovaMicrolab”), the Spanish Network for Research in Infectious Diseases (RD16/0016/0006), CIBERINFEC, project PI18/00501, funded by Instituto de Salud Carlos III and cofunded by European Union (ERDF, “A way to make Europe”), and PI21/00704, funded by Instituto de Salud Carlos III (ISCIII) and co-funded by the European Union, awarded to GB, and by CZ Vaccines. VFV is funded by a predoctoral fellowship from Xunta de Galicia (IN606A-2019/012).S

Virtual Reference in Seville University Library: A shared experience.

Los servicios de referencia en las bibliotecas universitarias están lejos de desaparecer y las tecnologías, en este caso las de la web social, están facilitando e impulsando una cada vez más demandada referencia virtual, con aplicaciones al alcance de todos. LibraryH3lp es un software en código abierto, que ha permitido a la Biblioteca de la Universidad de Sevilla establecer un servicio de referencia virtual que comparten sus 19 bibliotecas de área, para atender preguntas generales o especializadas temáticas , así como las dudas sobre el uso de su catálogo Fama. Se presenta una primera valoración del servicio que se pondrá en completa explotación en este curso académico 2009‐2010. Palabras clave: Referencia virtual, Bibliotecas universitarias, software en cóigo abierto, LibraryH3lp, Biblioteca de la Universidad de SevillaReference services in academic libraries are far from dead and technologies of the social web are facilitating and encouraging an ever-increasing demand for virtual reference with applications available to everyone. The open source software LibraryH3lp has enabled the Library of the University of Seville to establish a virtual reference service shared among 19 libraries to answer common and specialized questions and explain the use of the Fama library catalog. We present a first assessment of the service that will go live in the academic year 2009-2010

Entornos Virtuales y Aprendizaje de los estudiantes de la Escuela Profesional de Ingeniería de Sistemas de la Universidad Nacional de Huancavelica, Sede Pampas

Virtual environments represent great opportunities within the teaching-learning environment for both teachers and students in terms of flexibility, accessibility and many times in costs. The research aimed to establish the relationship between virtual environments and student learning at the Professional School of Systems Engineering at the National University of Huancavelica in 2018. The research was of the basic type, correlational level, design descriptive - correlational and made use of the general scientific method and the specific statistical and hypothetical deductive methods. The study population was made up of all the students of the Professional School of Systems Engineering of the National University of Huancavelica, which were 188 students, a probabilistic sample of 126 students was taken from them. The survey techniques were used with their survey questionnaire instruments with their reliability criteria (Cronbach's Alpha: 0.986) and the validity criterion (Expert judgment: 90%). The research concludes with a significance level of 5% that there is a strong direct and significant relationship (p - value: 0.000 < 0.010) between virtual environments and student learning at the Professional School of Systems Engineering at the National University. of Huancavelica in the period 2018.Los entornos virtuales representan grandes oportunidades dentro del ámbito de la enseñanza – aprendizaje tanto para los docentes como para los estudiantes en términos de flexibilidad, accesibilidad y muchas veces en costos. La investigación tuvo como objetivo establecer la relación que existe entre los entornos virtuales y el aprendizaje de los estudiantes de la Escuela Profesional de Ingeniería de Sistemas de la Universidad Nacional de Huancavelica en el periodo 2018. La investigación fue del tipo básico, nivel correlacional, diseño descriptivo – correlacional e hizo uso del método general científico y de los métodos específicos estadístico e hipotético deductivo. La población de estudio estuvo integrada por todos los estudiantes de la Escuela Profesional de Ingeniería de Sistemas de la Universidad Nacional de Huancavelica, que fueron 188 estudiantes, de ellos se tomó una muestra probabilística de 126 estudiantes. Se utilizó las técnicas de la encuesta con sus instrumentos cuestionario de encuesta con sus criterios de confiabilidad (Alfa de Cronbach: 0,986) y el criterio de validez (Juicio de experto: 90%). La investigación concluye con un nivel de significancia del 5% que existe una relación directa y significativa fuerte (p - valor: 0.000 < 0.010) entre los entornos virtuales y el aprendizaje de los estudiantes de la Escuela Profesional de Ingeniería de Sistemas de la Universidad Nacional de Huancavelica en el periodo 2018

Pleiotropic effects of cell wall amidase LytA on Streptococcus pneumoniae sensitivity to the host immune response

The complement system is a key component of the host immune response for the recognition and clearance of Streptococcus pneumoniae. In this study, we demonstrate that the amidase LytA, the main pneumococcal autolysin, inhibits complement-mediated immunity independently of effects on pneumolysin by a complex process of impaired complement activation, increased binding of complement regulators, and direct degradation of complement C3. The use of human sera depleted of either C1q or factor B confirmed that LytA prevented activation of both the classical and alternative pathways, whereas pneumolysin inhibited only the classical pathway. LytA prevented binding of C1q and the acute-phase protein C-reactive protein to S. pneumoniae, thereby reducing activation of the classical pathway on the bacterial surface. In addition, LytA increased recruitment of the complement downregulators C4BP and factor H to the pneumococcal cell wall and directly cleaved C3b and iC3b to generate degradation products. As a consequence, C3b deposition and phagocytosis increased in the absence of LytA and were markedly enhanced for the lytA ply double mutant, confirming that a combination of LytA and Ply is essential for the establishment of pneumococcal pneumonia and sepsis in a murine model of infection. These data demonstrate that LytA has pleiotropic effects on complement activation, a finding which, in combination with the effects of pneumolysin on complement to assist with pneumococcal complement evasion, confirms a major role of both proteins for the full virulence of the microorganism during septicemia.This work was supported by grant SAF2012-39444-C01/02 from MINECO. The Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES) and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER) are initiatives of ISCIII. E.R.-S. was supported by an FPU fellowship from MINECO.S