Rhipicephalus microplus salivary gland molecules induce differential CD86 expression in murine macrophages

<p>Abstract</p> <p>Background</p> <p>Tick parasitism is a major impediment for cattle production in many parts of the world. The southern cattle tick, <it>Rhipicephalus </it>(<it>Boophilus</it>) <it>microplus</it>, is an obligate hematophagous parasite of domestic and wild animals that serves as vector of infectious agents lethal to cattle. Tick saliva contains molecules evolved to modulate host innate and adaptive immune responses which facilitates blood feeding and pathogen transmission. Tick feeding promotes CD4 T cell polarization to a Th2 profile usually accompanied by down-regulation of Th1 cytokines through as yet undefined mechanisms. Co-stimulatory molecules on antigen presenting cells are central to development of T cell responses including Th1 and Th2 responses. Tick induced changes to antigen presenting cell signal transduction pathways are largely unknown. Here we document the ability of <it>R</it>. <it>microplus </it>salivary gland extracts (SGE) to effect differential CD86 expression.</p> <p>Results</p> <p>We examined changes in co-stimulatory molecule expression in murine RAW 264.7 cells in response to <it>R</it>. <it>microplus </it>SGE exposure in the presence of the toll-like receptor 4 (TLR4) ligand, LPS. After 24 hrs, CD86, but not CD80, was preferentially up-regulated on mouse macrophage RAW 264.7 cells when treated with SGE and then LPS, but not SGE alone. CD80 and CD40 expression was increased with LPS, but the addition of SGE did not alter expression. Higher concentrations of SGE were less effective at increasing CD86 RNA expression. The addition of mitogen or extracellular kinase (MEK) inhibitor, PD98059, significantly reduced the ability for SGE to induce CD86 expression, indicating activation of MEK is necessary for SGE induced up-regulation.</p> <p>Conclusions</p> <p>Molecules in SGE of <it>R. microplus </it>have a concentration-dependent effect on differential up-regulation of CD86 in a macrophage cell line activated by the TLR4 ligand, LPS. This CD86 up-regulation is at least partially dependent on the ERK1/2 pathway and may serve to promote Th2 polarization of the immune response.</p

Symmetries in Classical Field Theory

The multisymplectic description of Classical Field Theories is revisited, including its relation with the presymplectic formalism on the space of Cauchy data. Both descriptions allow us to give a complete scheme of classification of infinitesimal symmetries, and to obtain the corresponding conservation laws.Comment: 70S05; 70H33; 55R10; 58A2

New World screwworm (Cochliomyia hominivorax) myiasis in feral swine of Uruguay: one Health and transboundary disease implications

Background: Feral swine (Sus scrofa) are highly invasive and threaten animal and human health in the Americas. The screwworm (Cochliomyia hominivorax) is listed by the World Organization for Animal Health as a notifiable infestation because myiasis cases affect livestock, wildlife, and humans in endemic areas, and outbreaks can have major socioeconomic consequences in regions where the screwworm has been eradicated. However, a knowledge gap exists on screwworm infestation of feral swine in South America, where the screwworm is endemic. Here, we report screwworm infestation of feral swine harvested in Artigas Department (Uruguay), where the Republic of Uruguay shares borders with Brazil and Argentina. Methods: Myiasis caused by the larvae of screwworm were identified in feral swine with the support and collaboration of members of a local feral swine hunting club over a 3-year period in the Department of Artigas. Harvested feral swine were examined for the presence of lesions where maggots causing the myiasis could be sampled and processed for taxonomic identification. The sites of myiasis on the body of infested feral swine and geospatial data for each case were recorded. The sex and relative size of each feral swine were also recorded. Temperature and precipitation profiles for the region were obtained from public sources. Results: Myiases caused by screwworms were recorded in 27 of 618 the feral swine harvested. Cases detected in males weighing > 40 kg were associated with wounds that, due to their location, were likely caused by aggressive dominance behavior between adult males. The overall prevalence of screwworm infestation in the harvested feral swine was associated with ambient temperature, but not precipitation. Case numbers peaked in the warmer spring and summer months. Conclusions: This is the first report on myiasis in feral swine caused by screwworm in South America. In contrast to myiasis in cattle, which can reach deep into host tissues, screwworms in feral swine tended to cause superficial infestation. The presence of feral swine in screwworm endemic areas represents a challenge to screwworm management in those areas. Screwworm populations maintained by feral swine may contribute to human cases in rural areas of Uruguay, which highlights the importance of the One Health approach to the study of this invasive host species–ectoparasite interaction

Unambiguous Formalism for Higher-Order Lagrangian Field Theories

The aim of this paper is to propose an unambiguous intrinsic formalism for higher-order field theories which avoids the arbitrariness in the generalization of the conventional description of field theories, which implies the existence of different Cartan forms and Legendre transformations. We propose a differential-geometric setting for the dynamics of a higher-order field theory, based on the Skinner and Rusk formalism for mechanics. This approach incorporates aspects of both, the Lagrangian and the Hamiltonian description, since the field equations are formulated using the Lagrangian on a higher-order jet bundle and the canonical multisymplectic form on its dual. As both of these objects are uniquely defined, the Skinner-Rusk approach has the advantage that it does not suffer from the arbitrariness in conventional descriptions. The result is that we obtain a unique and global intrinsic version of the Euler-Lagrange equations for higher-order field theories. Several examples illustrate our construction.Comment: 21 pages; 4 diagrams; (this version) corrected typos; moved paragraphs; publishe

Desarrollo de germoplasma de maíz para suelos ácidos: programa suramericano de maíz CIMMYT.

La baja fertilidad de los uselos es el problema más importante en la reducción de los rendimiento de maíz en los tropicos y la acidez del suelo es el principal causante de esta baja fertilidad, siendo la toxicidad de aluminio la principal causa. Actualmente se seimbran entre 8 y 29 millones de ha. de maíz en suelos ácidos con bajo pH, alta concentración de Al, y deficiencia en Ca, Mg y P. En los suelos ácidos se inhibe el crecimiento radicular que finalmente se manifiesta en una dismimunción del rendimiento. El CIMMYT, en colaboración con los Programas Nacionales, esta aprovechando la gran variabilidad en el maíz para generar cultivares que puedan crecer bajo el estress provocado por la ácidez del suelo y que su cultivo sea una actividad económicamente viable y que no interfiera con la sosteniblidad del ambiente. Estudios realizados en Colombia y otros lugares indican que la selección recurrente recíproca, basada en el comportamiento de genotivos a través de un rango de ambiente será efectiva en el desarrollo de variedades e híbridos tolerantes. La capacidad de rendimiento en suelos ácidos esta correlacionada positivamente con el comportamiento en suelos fértiles no ácidos. Por esta razón, los cultivadores de maíz tolerantes a la acidez pueden crecer y produciir bien tanto en suelos ácidos en no ácidos. Como resultado de este proyecto colaborativo se han liberado dos cultivares de maíz: Sikuani ICA V110-Colombia y Antasena en Indonesia, actualmente en evaluación en diferentes países Estudios agronómicos indican la superioridad de los cultivares tolerantes con relación a los susceptibles o comerciales en un rango de suelos ácidos y no ácidosMaíz-Zea may

Classical field theory on Lie algebroids: Variational aspects

The variational formalism for classical field theories is extended to the setting of Lie algebroids. Given a Lagrangian function we study the problem of finding critical points of the action functional when we restrict the fields to be morphisms of Lie algebroids. In addition to the standard case, our formalism includes as particular examples the case of systems with symmetry (covariant Euler-Poincare and Lagrange Poincare cases), Sigma models or Chern-Simons theories.Comment: Talk deliverd at the 9th International Conference on Differential Geometry and its Applications, Prague, September 2004. References adde