107,140 research outputs found
IL-4-secreting CD4+ T cells are crucial to the development of CD8+ T-cell responses against malaria liver stages.
No full textCD4+ T cells are crucial to the development of CD8+ T cell responses against hepatocytes infected with malaria parasites. In the absence of CD4+ T cells, CD8+ T cells initiate a seemingly normal differentiation and proliferation during the first few days after immunization. However, this response fails to develop further and is reduced by more than 90%, compared to that observed in the presence of CD4+ T cells. We report here that interleukin-4 (IL-4) secreted by CD4+ T cells is essential to the full development of this CD8+ T cell response. This is the first demonstration that IL-4 is a mediator of CD4/CD8 cross-talk leading to the development of immunity against an infectious pathogen
Suelo sano hombre sano : guía del instructor
No full textGuía dirigida a los instructores de la especialidad en huerta casera en el que se explican prácticas agrícolas orientadas a la mejora y cuido de los suelos, ventajas de la agricultura biológica orgánica y prácticas sostenibles que a su vez permitan mejorar los cultivos y permitan obtener buenas cosechasGuide for the instructors of the specialty in home garden in which agricultural practices are explained oriented to the improvement and care of the soils, advantages of the organic biological agriculture and sustainable practices that in turn allow to improve the crops and allow to obtain good harvests¿Por qué una agricultura biológica? – Contenido del curso – Orientaciones generales para la utilización del curso18 página
Swift development of protective effector functions in naive CD8(+) T cells against malaria liver stages.
Full text linkWe generated T cell receptor transgenic mice specific for the liver stages of the rodent malaria parasite Plasmodium yoelii and studied the early events in the development of in vivo effector functions in antigen-specific CD8(+) T cells. Differently to activated/memory cells, naive CD8(+) T cells are not capable of exerting antiparasitic activity unless previously primed by parasite immunization. While naive cells need to differentiate before achieving effector status, the time required for this process is very short. Indeed, interferon (IFN)-gamma and perforin mRNA are detectable 24 h after immunization and IFN-gamma secretion and cytotoxic activity are detected ex vivo 24 and 48 h after immunization, respectively. In contrast, the proliferation of CD8(+) T cells begins after 24 h and an increase in the total number of antigen-specific cells is detected only after 48 h. Remarkably, a strong CD8(+) T cell-mediated inhibition of parasite development is observed in mice challenged with viable parasites only 24 h after immunization with attenuated parasites. These results indicate that differentiation of naive CD8(+) T cells does not begin only after extensive cell division, rather this process precedes or occurs simultaneously with proliferation
On K-stability of Fano weighted hypersurfaces
Full text linkLet X subset of P(a(0), ... , a(n)) be a quasi-smooth weighted Fano hypersurface of degree d and index I-X such that a(i) vertical bar d for all i. If I-X = 1, we show that, under a suitable condition, the alpha-invariant of X is greater than or equal to dim X/(dim X + 1) and X is K-stable. This can be applied in particular to any X as above such that dim X <= 3. If X is general and I-X < dim X, then we show that X is K-stable. We also give a sufficient condition for the finiteness of automorphism groups of quasi-smooth Fano weighted complete intersections
Suelo sano hombre sano : repelentes naturales. Unidad 3
No full textCartilla 3 del módulo de huertas ecológicas de la especialidad huerta casera en la que se explica cómo proteger las siembras mediante el uso de repelentes naturales de uso sostenible y amigable con el medio ambiente que permitan controlar mas no destruir especies y los métodos de preparación y aplicación de los repelentesPrimer 3 of the module of organic orchards of the specialty orchard home in which it is explained how to protect the sowings by means of the use of natural repellents of sustainable use and friendly with the environment that allow to control but not to destroy species and the methods of preparation and application of the repellentsRepelentes naturales -- Preparación de repelentes naturales22 página
Aseismic design for cut-and-cover tunnels: criteria and practical applications
No full textAn application of the Boundary Element Indirect Method is presented as a way to obtain design values of the “raking” of tunnels with rectangular cross section, subjected to earthquake excitation. Focus is on cut-and-cover type of tunnels, i.e. structure that are close to the ground surface. The features of the computer code UNDERGROUND are summarized. Applications to practical design cases show the importance of lateral diaphragms in the reduction of the design raking
Early self-regulatory mechanisms control the magnitude of CD8+ T cell responses against liver stages of murine malaria.
Full text linkFollowing immunization with Plasmodium yoelii sporozoites, the CD8(+) T cell population specific for the SYVPSAEQI epitope expressed in sporozoite and liver stages of this malaria parasite revealed the existence of a short term Ag presentation process that translated into a single clonal burst. Further expansion of this CD8(+) T cell population in conditions of sustained Ag exposure and additional supply of naive cells was inhibited by regulatory mechanisms that were developed as early as 24-48 h after priming. Studies using mouse models for Plasmodium or influenza virus infections revealed that this mechanism is Ag specific and is mediated by activated CD8(+) T cells that inhibit the priming of naive cells. This interference of the priming of naive cells appeared to result from limited access to Ag-presenting dendritic cells, which become disabled or are eliminated after contact with activated cells. Thus, concomitantly with the development of their effector antimicrobial capacity, CD8(+) T cells also acquire a self-regulatory role that is likely to represent one of the earliest mechanisms induced in the course of an immune response and that limits the magnitude of the early expansion of CD8(+) T lymphocytes reactive to microorganisms
Suelo sano hombre sano : ¿cómo mejorar un cultivo en desarrollo? Unidad 4
No full textCartilla 4 del módulo de huertas ecológicas de la especialidad huerta casera en la que se explican los principales factores que deben tenerse presentes para la evaluación del cultivo, cómo corregir defectos de un cultivo, cómo escoger las variedades de acuerdo con el ambiente apropiado, cómo corregir oportunamente los defectos que tenga el suelo y como controlar plagasPrimer 4 of the module of organic vegetable gardens of the home garden specialty in which the main factors that must be present for the evaluation of the crop, how to correct defects of a crop, how to choose the varieties according to the appropriate environment, how to correct timely defects that have the soil and how to control pestsFactores genéticos -- Factores de adaptación -- Factores del suelo -- Factores de competencia -- Factores de plagas -- Factores climáticos -- Extensión del problema -- Correctivos después de la cosecha -- El tiempo: un recurso valioso35 página
Actinocephalus delicatus Sano 2011, sp. nov.
No full textActinocephalus delicatus Sano, sp. nov. (Figs. 1, 2) Ab Actinocephalo brachypo habitu rhizomatoso, foliis glabris, scapis pilosis, bracteis paracladiorum intus glabris, bracteis florum apicibus et sepalorum apicibus obtusis, bracteis involucralibus hialine usque ad brunnea et floribus pistillatis pedicellatis differt. Type:— BRAZIL. Minas Gerais: Felício dos Santos, APA Felício dos Santos, Cachoeira do Sumidouro, 1350 m, 18 o 13’S, 43 o 15’W. 19 June 2006, P. L . Viana, F. S. F. Leite, L. E. Lopes & M. Ferreira 2512 (holotype SPF, isotype BHCB). Perennial herbs, 10–18 cm tall, with a rhizome producing basal rosettes, and paraclades axillary to the rosette leaves with an umbel of inflorescences at its apex. Rhizome 1–6 cm long. Leaves rosulate, flat, patent, linear, 3.0–6.5 × 0.1–0.2 cm, glabrous, apex acute, margin glabrous. Paraclades 1–5 per rosette, unramified, 6.5–16.5 × 0.3 cm, hirsute; paracladial bracts distributed along the paraclade and subtending the umbel of capitules, erect, linear, 1.0–2.5 × 0.1–0.2 cm, adaxial surface glabrous, abaxial surface glabrescent, apex acute, margins glabrescent, base semiamplexicaul. Spathes 0.3–0.5 cm long, glabrous, apex acute. Scapes 18–35 per paraclade, 1.5–2.0 cm long, tomentose with simple trichomes; capitula 2–4 mm in diameter, hemispheric; involucral bracts hyaline to light-brown, obovate, ca. 2 mm long, glabrous, apex obtuse, ciliate toward the apex; receptacle hemispheric, pubescent. Flowers 3-merous, ca. 14 per capitula: 10 staminates, 4 pistilates; floral bracts castaneous to golden-brown, oblong, concave, ca. 2 mm long, glabrous, apex obtuse, ciliate toward the apex. Staminate flowers ca. 2 mm; pedicel ca. 0.5 mm long, with long trichomes; sepals colored like floral bracts, fused at the base, obovate, concave, ca. 1 mm long, glabrous, apex obtuse, ciliate toward the apex; corolla tubular, membranaceous, hyaline, ca. 1.5 mm long, 3-lobed, glabrous; stamens ca. 2 mm long; pistillodes 3, papillose. Pistillate flowers ca. 2 mm; pedicel ca. 0.5 mm long, glabrous; sepals colored like floral bracts, obovate, concave, ca. 2 mm long, glabrous, apex obtuse, ciliate toward the apex; petals hyaline, oblong, ca. 1 mm long, glabrous, apex acute, ciliate toward the apex; gynoecium ca. 2 mm long, stigmatic branches completely fused, twice as long as the nectariferous branches; staminodes 3, scale-like. Fruit a loculicidal capsule. Distribution and ecology:— Actinocephalus delicatus is terrestrial or rupicolous and occurs in open areas, growing over rocky to sandy soils of the northeastern Espinhaço Range in Minas Gerais, Brazil. The species is known to occur in two distinct localities (Fig. 3): (1) in the Cachoeira do Sumidouro, in the Felício dos Santos municipality, a place predicted to be included in the Rio Preto State Park, where only a few individuals were found; and (2) in the Serra Negra State Park, in the Itamarandiba municipality, where a population of hundreds of individuals occurs throughout the Serra Negra. The individuals in the Cachoeira do Sumidouro were found in the riverbed, suggesting an aquatic habitat. These specimens were collected in June, in the dry season, so that it is unlikely that terrestrial individuals were flooded. However, we went to the area in the same season and, despite our intense search in the river edges and all around, we were unsuccessful to recover the species. As aquatic Actinocephalus are unknown, we suggest that the species is terrestrial, but some seeds germinated accidentally in the dry riverbed, where they were able to survive for a short while, without forming a perennial population. In addition, all the individuals in the Serra Negra are terrestrial or rupiculous, occurring in dry conditions, on sandy, free-draining soil. IUCN Red List category:— Actinocephalus delicatus is considered endangered (E) according to criteria B2a (IUCN 2008). Etymology:—The epithet refers to the delicate habit of the species, with its membranaceous leaves, and small and narrow paraclades. Notes:— Actinocephalus delicatus matches morphological architectural pattern I (sensu Oriani et al. 2008) due to its paraclades arising directly from a short aerial stem. Of all species exhibiting this pattern, A. delicatus shares morphological similarities with A. brachypus (Bong.) Sano (2004: 101) and A. herzogii (Moldenke) Sano (2004: 103). From the other Actinocephalus species it can be easily differentiated by its linear leaves, hirsute paraclades, hyaline to light-brown involucral bracts, and pedicelate pistillate flowers. Actinocephalus brachypus is the species morphologically most similar to A. delicatus. It shows approximately the same size of leaves, paraclades, and paracladial bracts, spathes and scapes, as well as a similar capitulum diameter. These common features give them a similar general habit, however they are easily distinguished, particularly by indumentum characters. Actinocephalus delicatus is a rhizomatous herb (vs. rhizome absent), with glabrous leaves (vs. hispid and ciliate), hirsute paraclades (vs. glabrous), and glabrous adaxial surface of the paracladial bracts (vs. hispid). It exhibits floral bracts and sepals of both staminate and pistillate flowers with obtuse apex (vs. acute). These species are also distinguished by the hyaline to light-brown involucral bracts (vs. dark-brown) and pedicelate pistillate flower (vs. sessile) in A. delicatus. Actinocephalus brachypus occurs in campos rupestres on the Diamantina Plateau (Minas Gerais), on roadsides between Diamantina and Gouveia (Sano 1999). Until now, both species were considered allopatric. Actinocephalus herzogii is divided into two varieties, distinguished mainly by overall size (Sano 1999). Individuals of Actinocephalus herzogii var. humilis (Sano) Sano (2004: 103) are distinctly smaller, and morphologically similar to A. delicatus. Both are rhizomatous herbs with linear leaves, hairy paraclades and scapes. They have approximately the same size of paraclades and spathes and pedicelate pistillate flowers, a very unusual characteristic in the genus. Actinocephalus delicatus is distinguished by its longer leaves (3.0– 6.5 cm vs. 2.0– 2.5 cm) with glabrous margins (vs. ciliate), linear erect paracladial bracts (vs. lanceolate patent), spathes with acute apices (vs. truncate), and glabrous sepals of the pistillate flowers (vs. hairy in abaxial surface base). Actinocephalus herzogii var. humilis occurs in campos rupestres on Chapada Diamantina (BA), in the vicinity of Piatã (Sano 1999), thus, these species occur allopatrically. Paratypes:— BRAZIL. Minas Gerais: Itamarandiba. Parque Estadual da Serra Negra, 18 o 00’ 20.2’’S, 42 o 43’ 28.9’’W, 13 September 2006, R. C . Mota, A. P. Fontana & K. A. Brahin 3089 (BHCB); Parque Estadual da Serra Negra, 18 o 00’ 31.7’’S, 42 o 43’ 46.7’’W, 1477 m, April 2010, L . Echternacht, T. V. Bastos, T. E. Almeida & A. M. de O. Santos 2140 (BHCB, P, SPF).Published as part of Echternacht, Livia, Trovó, Marcelo & Sano, Paulo Takeo, 2011, Two new species of Actinocephalus (Eriocaulaceae) from Minas Gerais, Brazil, pp. 26-36 in Phytotaxa 27 on pages 27-31, DOI: 10.11646/phytotaxa.27.1.3, http://zenodo.org/record/489415
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