939 resultados para Virus diseases of plants
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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A espécie Tomato severe rugose virus (ToSRV) é a predominante em áreas de cultivo de pimentão no Estado de São Paulo. Sua ocorrência na cultura é relativamente recente de modo que não existem informações sobre os danos causados nesta cultura. Os objetivos do presente trabalho foram avaliar a produtividade e qualidade dos frutos de pimentão de três cultivares (Magda, Amanda e Rubia R) quando infectadas com o ToSRV. Verificou-se acentuada redução no número de frutos e menor crescimento das plantas, porém, o ToSRV não influenciou significativamente na massa, diâmetro e comprimento dos frutos. Os resultados obtidos até o momento permitem concluir que o ToSRV causa danos em pimentão e que há necessidade de estudos visando resistência ao ToSRV.
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The aim of the present trial was to evaluate the heminested RT-PCR for the study of rabies virus distribution in mice inoculated experimentally. Inoculation was by the intramuscular route in 150 mice, using the dog street rabies virus. Groups of five animals were killed at different times. Fragments of different organs were collected and the material was tested by Fluorescent Antibody Test (FAT) and heminested RT-PCR (hn RT-PCR). Positive results were obtained beginning on the 10th day after inoculation in the brain, spinal cord, salivary gland, limbs, lungs, liver, spleen, urinary bladder, tongue and right kidney. Hn RT-PCR was shown to be more efficient for the study of rabies virus distribution in different tissues and organs. (C) 2004 Elsevier B.V.. All rights reserved.
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The aim of this study was to evaluate the importance of vaccination against Newcastle Disease (ND) in lovebirds (Agapornis roseicollis) and to investigate the state of carrier of the virus (NDV) in this species. There were used 48 lovebirds, distributed at random into 4 experimental groups: GI (Ulster 2C strain), Gil (B1 strain), Gill (LaSota strain) and GIV (non-vaccinated group). At 12 months of age, all groups were challenged with a pathogenic virus (NDV) suspension (ElD50 = 1081510.1 mL) and a group of Specific-Pathogen-Free (SPF) chicks were used as control of the virus. Cloaca) swabs from each bird were collected after 9, 14 and 21 days post-challenge for detection of genome viral excretion by Reverse Transcription Polymerase Chain Reaction RT-PCR. Lovebirds of GI, Gil and Gill did not demonstrate any signs of ND. They were refractory to the clinical disease. In lovebirds from the control group, NDV genome was detected 9 and 21 days after challenge. Therefore it was demonstrated the state of carrier of NDV by lovebirds. In birds from the vaccinated groups, genome viral excretion was not detected by RT-PCR. It was also demonstrated the importance of the vaccination in the suppression of the state of virus carrier of ND in lovebirds.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The anatomy and ultrastructure of root nodules of Anadenanthera peregrina var. falcata (Leguminosae-Mimosoideae) were analysed, as was plant growth. To ensure that nodules developed, seedlings were inoculated with a mixture of six strains of rhizobia. Nodules were produced that differed in appearance-and probably also effectiveness-but their structure was similar and they showed characteristics typical of indeterminate nodules, such as persistent meristematic tissue and a gradient of cells at different stages of development. Many starch grains were present in inner cortex cells and interstitial cells of infected tissue. Infected cells were densely packed with bacteroids, which contained many poly-beta-hydroxybutyrate granules. The high incidence of these granules, together with high levels of starch accumulation in interstitial cells, suggested low N-2-fixation efficiency of the rhizobia isolates used for inoculation. In the symbiosomes of early-senescent infected cells, reticulum-like structures, small vesicles and a fibrillar material were observed; these may be related to bacteroid degradation. In the cytoplasm of late-senescent infected cells, many vesicles and membrane-like structures were observed, probably associated with membrane degradation of bacteroids and peribacteroids. The total biomass of plants inoculated with rhizobia was low and their xylopodia and shoots had low levels of N compared with non-inoculated plants fertilized with ammonium nitrate. However, inoculated plants did not show N-deficiency symptoms and grew better than non-inoculated plants without N fertilization. These growth results, together with ultrastructural observations of nodules, suggest that nitrogen fixation of rhizobia isolates associated with Anadenanthera peregrina var. falcata roots is poor. (C) 2002 Annals of Botany Company.
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A toxicidade do alumínio (Al) é um dos fatores mais limitantes para a produtividade. Esta pesquisa foi realizada para avaliar a influência do Al, em solução nutritiva, na altura de plantas, no peso da matéria seca e nas alterações morfoanatômicas de raízes e folhas de milho (Zea mays L.). O experimento foi conduzido em casa de vegetação com tratamentos constituídos de cinco doses de Al (0; 25; 75; 150; e 300 µmol L-1) e seis repetições. As soluções foram constantemente aeradas e o pH foi ajustado a 4,3, inicialmente. A matéria seca da parte aérea e das raízes e a altura das plantas diminuíram significativamente com o aumento da concentração de Al. As raízes de plantas de milho cultivadas em soluções com Al tiveram seu crescimento inibido e apresentaram menos raízes laterais e desenvolvimento do sistema radicular inferior, em comparação com as das plantas-controle. As folhas das plantas crescidas em soluções que continham 75 e 300 µmol L-1 de Al não apresentaram muita diferença anatômica em relação às das plantas-controle. A bainha da folha das plantas exposta ao Al apresentou epiderme uniestratificada revestida por uma fina camada de cutícula e as células da epiderme e do córtex foram as que menos se desenvolveram. No feixe vascular, o metaxilema e protoxilema não tinham paredes secundárias, e o diâmetro de ambos foi muito menor quando comparado com os das plantas-controle.
Emerging infectious diseases in cetaceans worldwide and the possible role of environmental stressors
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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O tripes Frankliniella schultzei Trybom (Thysanoptera: Thripidae) é um dos mais importantes vetores de tomato spotted wilt tospovirus (TSWV) na cultura do tomate no Brasil. Dois métodos de aplicação do inseticida thiamethoxam foram comparados no controle de tripes em tomate. O experimento foi conduzido em delineamento de blocos ao acaso com sete tratamentos e quatro repetições. Utilizou-se um pulverizador costal manual com lança simples provida de ponta de pulverização com jato cônico vazio JD 14-2 ou modificada, com aplicador tipo esguicho, em substituição à ponta de pulverização. Dosagens de 150 e 200 g i.a. ha-1 foram usadas em única aplicação com esguicho e 50 g i.a. ha-1 em pulverizações semanais, iniciadas aos 48 dias após a semeadura. A eficiência do inseticida em teste foi comparada com diafenthiuron (400 g i.a. ha-1), profenofos + cypermethrin (320+32 g i.a. ha-1, respectivamente) e methamidophos (60 g i.a. 100 L-1 de água), aplicados em pulverização. Não houve diferença estatística entre os métodos de aplicação e doses com thiamethoxam no controle de F. schultzei aos 24 dias após a aplicação, sendo vantajosa a realização de uma única aplicação das maiores dosagens de thiamethoxam com esguicho em comparação às aplicações semanais da menor dosagem em pulverização. A eficiência de controle do tripes com o inseticida thiamethoxam variou de 93 a 95%, nos diferentes métodos e dosagens em teste. Diafenthiuron e profenofos + cypermethrin apresentaram eficiência menor (78 e 88%, respectivamente), porém foram superiores às obtidas com methamidophos (71%). Os produtos e doses utilizados não causaram fitotoxicidade às plantas de tomate.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Xylella fastidiosa is an important pathogen bacterium transmitted by xylem-feedings leafhoppers that colonizes the xylem of plants and causes diseases on several important crops including citrus variegated chlorosis (CVC) in orange and lime trees. Glutathione-S-transferases (GST) form a group of multifunctional isoenzymes that catalyzes both glutathione (GSH)-dependent conjugation and reduction reactions involved in the cellular detoxification of xenobiotic and endobiotic compounds. GSTs are the major detoxification enzymes found in the intracellular space and mainly in the cytosol from prokaryotes to mammals, and may be involved in the regulation of stress-activated signals by suppressing apoptosis signal-regulating kinase 1. In this study, we describe the cloning of the glutathione-S-transferase from X. fastidiosa into pET-28a(+) vector, its expression in Escherichia coli, purification and initial structural characterization. The purification of recombinant xfGST (rxfGST) to near homogeneity was achieved using affinity chromatography and size-exclusion chromatography (SEC). SEC demonstrated that rxfGST is a homodimer in solution. The secondary and tertiary structures of recombinant protein were analyzed by circular dichroism and fluorescence spectroscopy, respectively. The enzyme was assayed for activity and the results taken together indicated that rxfGST is a stable molecule, correctly folded, and highly active. Several members of the GST family have been extensively studied. However, xfGST is part of a less-studied subfamily which yet has not been structurally and biochemically characterized. In addition, these studies should provide a useful basis for future studies and biotechnological approaches of rxfGST. (C) 2008 Elsevier B.V. All rights reserved.
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As part of a study of plants involved in crystal-associated hepatogenous photosensitization diseases, samples of Brachiaria decumbens and Panicum dichotomiflorum on which cattle and goats had recently been photosensitized were analyzed. The level of saponins associated with these photosensitization outbreaks were determined by GC-MS. Only low levels of Pithomyces chartarum spores were present on the B decumbens, and all isolates obtained failed to produce sporidesmin.
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An integrated and interdisciplinary research programme with native medicinal plants from tropical forests has been performed in order to obtain new forest products for sustainable use in regional markets vis-à-vis ecosystem conservation. For the success of this programme ethnopharmacological studies are very important with respect to (i) identification of useful plants including medicinal and aromatic species; (ii) recuperation and preservation of traditional knowledge about native plants; and (iii) identification of potential plants with economic value. The plants are selected with a view to evaluate efficacy and safety (pharmacological and toxicological studies), and phytochemical profile and quality control (phytochemical and chromatographic characterization). These studies are very important to add value to plant products and also to mitigate unscrupulous exploitation of medicinal plants by local communities, since multiple use of plants represents an excellent strategy for sustaining the tropical ecosystem through ex situ and in situ conservation. Thus, conservation of tropical resources is possible in conjunction with improvements in the quality of life of the traditional communities and production of new products with therapeutic, cosmetic and 'cosmeceutic' value. © NIAB 2005.
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Isotope screening is a simple test for determining the photosynthetic pathway used by plants. The scope of this work was to classify the photosynthetic type of some herbs and medicinal plants through studies of the carbon isotope composition (δ13C). Also, we propose the use of carbon isotope composition as a tool to control the quality of herbs and medicinal plants. For studies of δ13C, δ 13C‰ = [R (sample)/R (standard) - 1] × 10-3, dry leaves powdered in cryogenic mill were analyzed in a mass spectrometer coupled with an elemental analyzer for determining the ratio R = 13CO2/12CO2. In investigation of δ13C of 55 species, 23 botanical families, and 44 species possessed a C3 photosynthetic type. Six species found among the botanical families Euphorbiaceae and Poaceae were C4 plants, and 5 species found among the botanical families Agavaceae, Euphorbiaceae, and Liliaceae possessed CAM-type photosynthesis. Carbon isotope composition of plants can be used as quality control of herbs and medicinal plants, allowing the identification of frauds or contaminations. Also, the information about the photosynthetic type found for these plants can help in introducing and cultivating exotic and wild herbs and medicinal plants.