Structural basis of complement membrane attack complex formation

In response to complement activation, the membrane attack complex (MAC) assembles from fluid-phase proteins to form pores in lipid bilayers. MAC directly lyses pathogens by a ‘multi-hit’ mechanism; however, sublytic MAC pores on host cells activate signalling pathways. Previous studies have described the structures of individual MAC components and subcomplexes; however, the molecular details of its assembly and mechanism of action remain unresolved. Here we report the electron cryo-microscopy structure of human MAC at subnanometre resolution. Structural analyses define the stoichiometry of the complete pore and identify a network of interaction interfaces that determine its assembly mechanism. MAC adopts a ‘split-washer’ configuration, in contrast to the predicted closed ring observed for perforin and cholesterol-dependent cytolysins. Assembly precursors partially penetrate the lipid bilayer, resulting in an irregular β-barrel pore. Our results demonstrate how differences in symmetric and asymmetric components of the MAC underpin a molecular basis for pore formation and suggest a mechanism of action that extends beyond membrane penetration

Assessment of the Effect of Satureja montana and Origanum virens Essential Oils on Aspergillus flavus Growth and Aflatoxin Production at Different Water Activities

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).Aflatoxin contamination of foodstuffs poses a serious risk to food security, and it is essential to search for new control methods to prevent these toxins entering the food chain. Several essential oils are able to reduce the growth and mycotoxin biosynthesis of toxigenic species, although their efficiency is strongly influenced by the environmental conditions. In this work, the effectiveness of Satureja montana and Origanum virens essential oils to control Aspergillus flavus growth was evaluated under three water activity levels (0.94, 0.96 and 0.98 aw) using a Bioscreen C, a rapid in vitro spectrophotometric technique. The aflatoxin concentrations at all conditions tested were determined by HPLC-FLD. Aspergillus flavus growth was delayed by both essential oil treatments. However, only S. montana essential oil was able to significantly affect aflatoxin production, although the inhibition percentages widely differed among water activities. The most significant reduction was observed at 0.96 aw, which is coincident with the conditions in which A. flavus reached the highest levels of aflatoxin production. On the contrary, the treatment with S. montana essential oil was not effective in significantly reducing aflatoxin production at 0.94 aw. Therefore, it is important to study the interaction of the new control compounds with environmental factors before their application in food matrices, and in vitro ecophysiological studies are a good option since they provide accurate and rapid results.Peer reviewedFinal Published versio

Producción de ocratoxina en las principales especies de "Aspergillus" sección cirdumdati estudio de los genes implicados, métodos de detección y control

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Biológicas, Departamento de Microbiología III, leída el 22/06/2011.Depto. de Genética, Fisiología y MicrobiologíaFac. de Ciencias BiológicasTRUEProQuestpu

Evolución de las compañías aéreas de bajo coste en el mercado europeo; pasado, presente y futuro

El presente trabajo de investigación se centrará en un análisis de la evolución de las compañías aéreas de bajo coste en Europa. A través del mismo se podrá observar cómo este patrón de la industria aeronáutica ha ido creciendo y ha ido penetrando en el mercado europeo hasta convertirse en uno de los modelos de negocio más exitosos. En un principio se analizarán ambos tipos de compañías (tradicionales y de bajo coste) realizando una comparativa para poder observar, de una forma más detallada, que es lo que caracteriza el “low cost”. Se hablará también de la evolución de este modelo y su impacto en la comercialización y a través de diversas fuentes de información, echar un vistazo hacia el futuro de las mismas.This research will focus on an analysis of the evolution of low cost airlines in Europe. Through it, we can see how this pattern of the aviation industry has been growing and it has penetrated the European market to become one of the most successful business models. Initially both types of companies (traditional and low cost) will be analyzed by performing a comparative to see, in a more detailed way, what is characterizes the "low cost". It will also discuss the evolution of this model and its impact on marketing and through different sources of information, have a look at the future of them.Serna Gil, A. (2014). Evolución de las compañías aéreas de bajo coste en el mercado europeo; pasado, presente y futuro. Universitat Politècnica de València. http://hdl.handle.net/10251/47231Archivo delegad

Evolución de la comunicación publicitaria, de la intracción de S.XX al horizonte de la autoacción

A través del presente trabajo se desarrollara una nueva visión personal de la evolución de la comunicación publicitaria entre marcas y usuarios. Partiendo de un contexto en constante variación, se han elaborado una serie de factores temporales lineales, que coinciden con cada uno de los cuatro factores comunicativos en los que se divide el objeto de estudio, de INTRACCIÓN - Siglo XX hasta AUTOACCIÓN - Año 2.020 en adelante. Para poder comprender las diferencias de estos factores comunicativos según el transcurso de los años, concretare en cada uno de los siete conceptos propios necesarios para explicar y entender de forma más precisa esta comunicación publicitaria, de reacción a reinvención. Gracias a las magnitudes dependientes de los conceptos y las variables que ayudan al desarrollo de estas, se explicará en su conjunto la hipótesis de estudio, y entenderemos la evolución del consumidor, de comprador a smartsumer, y de su comunicación con las marcas.Departamento de Historia Moderna, Contemporánea y de América, Periodismo y Comunicación Audiovisual y PublicidadGrado en Publicidad y Relaciones Pública

Caracterización estructural de las chaperonas TBCE y TBCB, involucradas en la Homeostasis de Tubulina Alfa

Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 07-05-2013Microtubules are cytoskeletal elements made up of αβ-­‐tubulin heterodimers that provide structural support for the cell and play important roles in key cellular processes such as cell division, cell motility and intracellular transport. In contrast to other cytoskeletal components (i.e. actin), the α and β-­‐tubulin heterodimer biogenesis pathway involves not only the cytosolic chaperonin CCT for proper folding of the monomer but also a number of tubulin binding cofactors (TBCA-­‐E). Upon one or several rounds of ATPase dependent cycles of CCT activity, quasi-­‐native monomers of tubulin are released from the chaperonin. These folding intermediates subsequently interact with cofactors in a stepwise process that generates assembled competent heterodimers. Furthermore, cofactors D and E can dissociate native heterodimers and might also regulate tubulin monomers degradation. Therefore, these proteins would take an important role in the spatial and temporal regulatory pathway of microtubule dynamic instability. Previously, it has been proposed that some of these domains (i.e. Ubl domains) mediate the interaction between different cofactors and those cofactors with tubulin in a regulated manner that determines microtubule stability or dynamicity. However, no cofactor-­‐cofactor complex or cofactor-­‐substrate complex structures have been solved up to now, and the specific regions of interaction remain to be mapped. Here we present a structural analysis by transmission electron microscopy and image processing techniques of the full-­‐length TBCE protein and the ternary α-­‐tubulin:TBCE:TBCB (αEB) complex. The interpretation of the reconstructed electron density maps of TBCE and αEB by fitting the already known atomic structures of several domains of the cofactors has allowed us to elucidate the protein configuration inside the complex and thus the interaction regions that mediate complex formation and stabilization. Finally, we suggest a model that may provide insights into the molecular mechanism that drives the αβ-­‐tubulin heterodimer dissociation

Comunicación corta. Rhizoctonia solani, agente causal de la muerte de plántulas de acelga en España

During September 2011, post-emergence damping off of Swiss chard (Beta vulgaris subsp. cicla L.) was observed in a greenhouse in Villa del Prado (Spain). About 20% of the seedlings showed damping off symptoms. Lesions were initially water soaked, dark brown necrosis of crown tissue, irregular in shape and sunken in appearance on large plants, causing the infected seedlings to collapse and eventually die. Rhizoctonia solani was isolated consistently from symptomatic plants. After morphological and molecular identification of the isolates, pathogenicity was tested by placing agar plugs of four isolates adjacent to the stem at the three or four true leaf stage. In inoculated plants, brown crown and stem necrosis occurred while control plants did not show disease symptoms. Pathogenicity using non-germinated seeds was also tested. All four isolates produced extensive damping off when inoculated on non-germinated seeds. To our knowledge, this is the first report of damping off of Swiss chard caused by R. solani in Europe.En el mes de septiembre de 2011, se observó muerte de plántulas en acelgas cultivadas en un invernadero en Villa del Prado (España). Cerca del 20% de los semilleros mostraban síntomas de caída de plántulas. Las lesiones iniciales tenían un aspecto húmedo y consistían en una necrosis del tejido de la corona de color marrón oscuro, de bordes irregulares y deprimidos en las plantas adultas, produciendo el colapso de las plántulas y, ocasionalmente, la muerte de las mismas. Rhizoctonia solani se aisló de manera consistente de las plantas sintomáticas. Tras una identificación morfológica y molecular, la patogenicidad de los aislados se probó colocando discos de agar adyacentes al tallo de la planta en estados de tres o cuatro hojas verdaderas. En las plantas inoculadas se observó un oscurecimiento de la corona y la necrosis del tallo en todos los casos, síntomas que no mostraron las plantas control. Por otro lado, se comprobó la patogenicidad de los aislados en semillas no germinadas. Los cuatro aislados produjeron muerte de plántulas cuando se inocularon en semillas no germinadas. Hasta donde hemos podido comprobar, este trabajo parece ser la primera cita de muerte de plántulas de acelga causada por R. solani en Europa

Genetic regulation of aflatoxin, ochratoxin A, trichothecene, and fumonisin biosynthesis: A review

Mycotoxins are a significant food safety concern. Aflatoxins, trichothecenes, fumonisins, and ochratoxin A are considered the most important mycotoxins due to their frequent occurrence in food products and their well-known toxicity. The regulation of mycotoxin biosynthesis occurs mainly at transcriptional level, and specific regulators have been described in every biosynthetic cluster. Secondary metabolite production, including mycotoxin synthesis, is also regulated by general regulator pathways affected by light, osmotic stress and oxidative stress, among others. This review is focused on this genetic regulation of mycotoxin biosynthesis by specific genes and global regulators

Percepción que tienen los estudiantes del grado 10 de la Escuela Normal Superior de Quibdó sobre las prácticas culturales de tradición oral (Alabaos y Gualíes).

Para la supervivencia de la cultura negra, la oralidad ha sido el instrumento de mayor importancia en el Pacífico Colombiano, sus habitantes históricamente han utilizado el relato y la conversa para comunicarse, transmitiendo y recreando su cotidianidad de boca en boca y generación tras generación. Cotidianidad mágica de donde han surgido expresiones y manifestaciones propias, como puntales de nuestra dinámica sociocultural. De donde se desprenden expresiones como el cuento tradicional, cuya enseñanza ha impulsado valores formativos como la cooperación, la amistad o la unidad; y delineado un hilo conductor para mantener constante relación de convivencia, verse como familia, Los afrocolombianos se han caracterizado por tener un alto grado de religiosidad. Las manifestaciones de esta religiosidad son los mitos y las creencias en espíritus y seres sobrenaturales, por esta razón resulta de suma importancia que la escuela siga siendo ese vínculo generacional, espontáneo, de intercambio y con una inercia cultural, a todos los niveles educativos, edad y sexo en cada sociedad. La problemática más evidente de la que se ocupa esta investigación es la pérdida de identidad, proceso de aculturación, prejuicios, mutación de las prácticas culturales de tradición oral y negación del yo, de los estudiantes de los grados 10 de la Escuela Normal Superior de Quibdó. Estos hechos representan una clara señal del desarraigo social y cultural. Se hace muy evidente el caso de los ritos fúnebres como son sus tradicionales alabaos y gualíes muy propios de los comunidades chocoanas, ya que estos juegan un papel fundamental en la historia de los pueblos afros. En los cantos de alabaos y gualíes, se expresa la tradición oral de las comunidades negras del pacifico colombiano, que se trasmite de generación en generación. Estos cantos a su vez expresan una serie de conocimientos sobre la cultura afrocolombiana y sus tradiciones, por lo cual son un referente para su identidad. La educación debe jugar un papel preponderante, en mantener y conservar la cultura de los pueblos y en este aspecto la ley en materia educativa, facilita que se incorporen a los PEI, de cada institución cátedras que mantengan, fortalezcan y difundan sus tradiciones. Desde este punto de vista, la Etnoeducación es el elemento trasversal de la educación de los pueblos, para que sus costumbres e idiosincrasia sean relevantes a la hora de formar a los futuros hombres y mujeres de este paísFor the survival of the black culture, orality has been the most important instrument in the Colombian Pacific, its inhabitants have historically used the story and the conversation to communicate, transmitting and recreating their daily life from mouth to mouth and generation after generation. Magical everydayness from which expressions and manifestations of our own have emerged, as props of our sociocultural dynamics. Whence expressions such as the traditional story emerge, whose teaching has promoted formative values ​​such as cooperation, friendship or unity; and outlined a common thread to maintain a constant relationship of coexistence, see yourself as a family, Afro-Colombians have been characterized as having a high degree of religiosity. The manifestations of this religiosity are the myths and beliefs in spirits and supernatural beings, for this reason it is of the utmost importance that the school continues to be that generational, spontaneous, exchange and cultural inertia link, at all educational levels, age and sex in each society. The most obvious problem that this research deals with is the loss of identity, acculturation process, prejudices, mutation of cultural practices of oral tradition and denial of the self, of the students of the 10th grades of the Higher Normal School of Quibdó . These facts represent a clear sign of social and cultural uprooting. It becomes very evident the case of the funeral rites as they are their traditional alabaos and gualíes very own of the chocoanas communities, since these play a fundamental role in the history of the Afro towns. In the songs of alabaos and gualíes, the oral tradition of the black communities of the Colombian Pacific is expressed, which is transmitted from generation to generation. These songs, in turn, express a series of knowledge about the Afro-Colombian culture and its traditions, for which they are a reference for their identity. Education must play a preponderant role, in maintaining and preserving the culture of the people and in this aspect the law on education, facilitates the incorporation into the PEI of each institution chairs that maintain, strengthen and disseminate their traditions. From this point of view, Ethnoeducation is the transversal element of the education of the peoples, so that their customs and idiosyncrasies are relevant when training the future men and women of this country