832 research outputs found
Interleukin-21 expanded NKDC in vitro reduces the B16F10 tumor growth in vivo
AbstractInnate immunity to tumors is mediated mainly by natural killer cells (NKs) and dendritic cells (DCs). The function of these cells is coordinated by cytokines produced during the inflammatory process. NK cells are highly active against tumors, being an important source of IFN-γ. Natural killer dendritic cells (NKDCs) were recently identified as a group of hybrid cells; some studies claim that they have lytic activity, produce IFN-γ and can also stimulate antigen-specific T cells. Interleukin 21 (IL-21) regulates the proliferation capacity and cytotoxicity of NK and T cells. The main objective of this study was to investigate if IL-21 influences the frequency of NKDCs in vitro as well as IFN-γ production and also to verify if these cells could enhance the antitumor activity against B16F10 tumor model in vivo. Splenocytes from C57BL/6 mice were isolated and the DC were enriched by immunomagnetic beads and cultured for four days with recombinant IL-21 (10, 20, 40 or 100ng/ml). NKDC population was characterized as CD11clow/medB220+NK1.1+. Expanded cells were used to treat B16F10 tumor bearing mice and tumor growth was compared between the doses of IL-21 10ng/ml and 20ng/ml. The results indicate that IL-21 increases the expansion of splenic NKDCs in vitro in doses of 10ng/ml and 20ng/ml and these cells produce IFN-γ. In vivo, cells expanded with IL-21 and injected directly into the growing tumor efficiently reduced the tumor size. Together, these results showed for the first time that IL-21 influences the biology and the effector activity of NKDCs
Response of the Coccinellidae Community within Sustainable Vineyards to the Surrounding Landscape
The family Coccinellidae (Coleoptera) includes important predatory natural enemies in agricultural
crops. To survive, this group uses different occurring resources across the landscape; therefore,
the landscape can influence the Coccinellidae community in agroecosystems. In this context, this
work aims to evaluate the response of the Coccinellidae community to the landscape context within
a gradient of distances from vineyards managed under sustainable production methods. For that,
Coccinellidae were sampled in thirty-five vineyards distributed by six wine Protected Designation of
Origin (PDO) regions of Portugal, and landscape metrics—composition and configuration—were
calculated in a 2000 m, 1500 m, 1000 m, 750 m, and 500 m buffers around the vineyards. Then,
Coccinellidae species were identified, and the response of the Coccinellidae to the landscape metrics
was analyzed. In total, 326 Coccinellidae from 21 species were collected. The most abundant species
were Scymnus apetzi, Scymnus interruptus, Scymnus subvillosus, Coccinella septempunctata, and Stethorus
pusillus, which together represented 83.4% of the total collected individuals. Most specimens were
concentrated in July and at the vegetation cover. Results from the statistical analysis (Generalized
Linear Mixed Models) indicated that the presence of seminatural habitat surrounding the crop may
favor Coccinellidae, while habitat fragmentation seems detrimental for them. The potential relevance
of the identified Coccinellidae for pest control in vineyards is discussedinfo:eu-repo/semantics/publishedVersio
Coccinellídeos associados ao olival da Beira Interior
Com o objectivo de obter informação sobre as espécies de coccinelídeos associadas ao olival
da Beira Interior, em 2003 e 2004 efectuaram-se amostragens em dois olivais considerados
401 representativos das condições da região. As amostragens decorreram entre Maio e Outubro
de cada um dos anos, a uma periodicidade aproximadamente quinzenal, tendo consistido no
batimento de dois ramos por árvore em cada uma de 25 árvores seleccionadas ao acaso por
olival e data. A quase totalidade das capturas (96,3% em 2003 e 93,2% em 2004), obteve-se
entre o início de Julho e o início de Outubro, quando se interromperam as amostragens. Os
exemplares capturados identificaram-se como pertencendo a I 5 espécies, isto é: Chilocorus
bipustulotus L, Exochomus nigromoculotus (Gze.), Exochomus quodripustulotus L, Plotynaspis luteorubro
Gze., Stethorus punctillum Ws.), Scymnus (Scymnus) abietis (Paykull.), Scymnus (Scymnus)
apetzi Muls., Scymnus (Scymnus) interruptus Gze., Scymnus (Pu/Jus) mediterraneus Khnz., Scymnus
(Pullus) subvillosus Gze., Nephus (Bipunaotus) bisignotus Boheman, Coccinello septempunaoto (L.),
Propyloea quotuordecimpuntocto (L), Rhyzabius laphontae (Biaisd.) e Rhyzobius litura Fabr. A espécie
capturada em maior número, em qualquer dos olivais e anos de estudo, foi S. interruptus, que
representou 61,3% do total de exemplares obtidos
Linear and nonlinear models in wind resource assessment and wind turbine micro-siting in complex terrain
The current trend of increasing the electricity production from wind
energy has led to the installation of wind farms in areas of greater
orographic complexity, raising doubts on the use of simple, linear,
mathematical models of the fluid flow equations, so common in the
wind energy engineering. The present study shows how conventional
techniques, linear models and cup anemometers, can be
combined with flow simulation by computational fluid dynamics
techniques (nonlinear models) and measurements by sonic anemometers,
and discuss their relative merits in the characterisation of
the wind over a coastal region—a cliff over the sea. The computational
fluid dynamic techniques were particularly useful, providing a
global view of the wind flow over the cliff and enabling the
identification of separated flow regions, clearly unsuitable for
installation of wind turbines. These locations display a pulsating
flow, with periods between 1 and 7min, in agreement with sonic
anemometer measurements, and both a turbulence intensity and a
gust factor well above the wind turbine design conditions.The authors acknowledge the support of the Portuguese Foundation for Science and Technology
(FCT), under research Project TURBWIND (POCI/ENR/60965/2004). Data from the field experiment
were kindly supplied by EEM-Empresa de Electricidade da Madeira, SA.info:eu-repo/semantics/publishedVersio
Abundance and diversity of potential vectors of Xylella fastidiosa in four different wine regions of Portugal
Xylella fastidiosa, is a phytopathogenic bacterium, responsible for serious diseases in important
crops, such as Pierce’s Disease in grapevines. The recent detection of this bacterium in Portugal
is worrying, since this bacterium can spread rapidly via xylem-sap feeder insects, mainly belonging
to Hemiptera Cicadomorpha. In this context, the goal of this work was to detect the abundance and
diversity of possible vectors of X. fastidiosa in vineyards from different wine regions of Portugal. For
that, in 2018, 21 vineyards with ground cover and from four different wine regions of Portugal (i.e.,
“Trás-os-Montes”, “Vinho Verde”, “Bairrada”, and “Peninsula de Setúbal”) were sampled for adults of
Auchenorrhyncha, during three distinct periods (beginning of July, mid September and mid October).
Sampling was performed in the ground and in the aerial part of the vines. In each sampling date,
10 samples of 10 sweepings were collected on the ground in each vineyard. On the aerial part of
the vines, 10 samples of 50 sweepings were collected in 3 lines of the vineyard. A total of 3543
Cicadomorpha were collected on the 3 sampling dates, being the highest abundance observed in
the mid September. The “Trás-os-Montes” and “Bairrada” regions, in general, presented the highest
abundance of insects of this infraorder, but it was in “Vinho Verde” region that there was a highest
abundance of potential vectors: Philaenus, Neophilaenus and Cicadelli viridis.Work funded by the project H2020-SFS-2016-3. RIA, contrato 727987 “XF-ACTORS: Xylella
fastidiosa Active Containment Through a multidisciplinary-Oriented Research Strategy”.info:eu-repo/semantics/publishedVersio
Capillary electrophoresis-mass spectrometry characterisation of secondary metabolites from the antihyperglycaemic plant Genista tenera
Genista tenera is endemic to the Portuguese island of Madeira, where an infusion of the aerial parts of the plant is used in folk medicine as an antidiabetic agent. Consequently the medicinal properties of the secondary metabolites of this plant have been the subject of an ongoing study. A recently reported LC-MS method using a 100 min separation allowed identification of five flavonoid components in an extract of the aerial parts of this plant. In order to obtain additional information on the range and complexity of the plant’s secondary metabolite components a CE-MS method has been developed and applied for the analysis of an extract of G. tenera. Twenty-six different components are distinguished in an analysis time of only 10 min. Results demonstrate that CE-MS/MS rapidly generates data complementary to those obtainable by LC-MS/MS and is particularly suited to the analysis of plant metabolites where concentration is not limiting.BBSRC, University of York, Treaty of Windsor Anglo-Portuguese joint research programme, Thermo Electron, Analytical Chemistry Trust Fund, Royal Society of Chemistry Analytical Division, Engineering and Physical Sciences Research Council (EPSRC)info:eu-repo/semantics/publishedVersio
Grapevine under deficit irrigation: hints from physiological and molecular data
Background - A large proportion of vineyards are located in regions with seasonal drought (e.g. Mediterraneantype
climates) where soil and atmospheric water deficits, together with high temperatures, exert large constraints
on yield and quality. The increasing demand for vineyard irrigation requires an improvement in the efficiency of
water use. Deficit irrigation has emerged as a potential strategy to allow crops to withstand mild water stress with
little or no decreases of yield, and potentially a positive impact on fruit quality. Understanding the physiological
and molecular bases of grapevine responses to mild to moderate water deficits is fundamental to optimize deficit
irrigation management and identify the most suitable varieties to those conditions.
Scope - How the whole plant acclimatizes to water scarcity and how short- and long-distance chemical and
hydraulic signals intervene are reviewed. Chemical compounds synthesized in drying roots are shown to act
as long-distance signals inducing leaf stomatal closure and/or restricting leaf growth. This explains why some
plants endure soil drying without significant changes in shoot water status. The control of plant water potential
by stomatal aperture via feed-forward mechanisms is associated with ‘isohydric’ behaviour in contrast to ‘anysohydric’
behaviour in which lower plant water potentials are attained. This review discusses differences in this
respect between grapevines varieties and experimental conditions. Mild water deficits also exert direct and/or
indirect (via the light environment around grape clusters) effects on berry development and composition; a
higher content of skin-based constituents (e.g. tannins and anthocyanins) has generally being reported.
Regulation under water deficit of genes and proteins of the various metabolic pathways responsible for berry
composition and therefore wine quality are reviewed
Deficit irrigation in Mediterranean environment. What lessons have we learnt from grapevine studies ?
Libro de Actas - X Simposium Hispano Português de Relaciones Hidricas, 2010Deficit irrigation techniques, implying that water is supplied at levels below full crop evapotranspiration
throughout the growing season or in specific phenological stages, such as regulated deficit irrigation
(RDI) or partial root drying (PRD), emerged as potential strategies to increase water savings with
marginal decreases of yield and likely positive impact on fruit quality. Understanding the physiological
and molecular bases for plant responses to mild to moderate water deficits is of utmost importance to
modulate the appropriate balance between vegetative and reproductive development, to improve crop
water-use efficiency and to control fruit quality. It is acknowledged that the timing and intensity of the
response to soil and atmospheric water deficits, namely in what concerns stomatal control, depends
greatly on the genotype. This has profound implications in irrigation management, in particular the
timing and amount of irrigation to optimize source-sink relationships and achieve optimal fruit quality in
each variety. Mild water deficits also exert direct and/or indirect (via the light environment in the cluster
zone) effects on berry development and composition. A current research challenge is determining how
the environment, in particular water deficits, regulates genes and proteins of the various metabolic
pathways responsible for berry composition and therefore for wine qualit
A serologia para avaliação do papel dos predadores em olival biológico
A oliveira, sendo uma planta mediterrânica, encontra-se bem adaptada em Portugal. Apesar de ser uma cultura
com poucos problemas fitossanitários, por vezes e sujeita à acção de algumas pragas e doenças. De entre as
pragas de artrópodos destacam-se a traça da oliveira, Prays oleae (Bern.), a mosca da azeitona, Bactrocera oleae (GmeL) e a cochonilha negra, Saissetia oleae (Oliv.). No entanto, as populações destes inimigos podem ser mantidas abaixo do nível económico de ataque por factores abióticos e/ou por outros artrópodos, espécies
predadoras e parasitóides, que contribuem para a estabilidade da biocenose no olival A valorização destes
auxiliaras é, assim, um factor preponderante na protecção contra pragas da oliveira, nomeadamente em modo de
produção biológico
Produção de antissoros policlonais para detecção de predadores das principais pragas da oliveira
A oliveira está bem adaptada às áreas mediterrâneas mas por vezes é sujeita à acção de inimigos,
nomeadamente a traça da oliveira, Prays oleae (Bern.), a mosca da azeitona, Bactrocera oleae (Gmel.) e a
cochonilha negra, Saissetia oleae (Oliv.). No entanto, as populações destes inimigos podem ser mantidas abaixo
do nível económico de ataque por factores abióticos e bióticos. Entre estes incluem-se espécies predadoras e
parasitóides que contribuem para a estabilidade da biocenose. A valorização dos auxiliares artrópodos é,
assim, factor preponderante na protecção contra pragas da oliveira, nomeadamente em modo de produção
biológico.
A utilização de técnicas serológicas, particularmente ELISA (enzyme linked immunosorbent assay), para
avaliação da predação em artrópodos, já é bastante utilizada.
Para futuramente se avaliar o papel dos predadores em olivais conduzidos de acordo com o modo de
produção biológico, em Trás-os-Montes e no Alentejo, produziram-se antissoros policlonais para monitorizar
as três pragas nos seus principais predadores. Este trabalho refere a preparação dos antigénios, o protocolo de
imunização dos coelhos, a colheita dos antissoros e sua caracterização preliminar por ELISA
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