Estudos biológicos e moleculares de um isolado necrótico de bean yellow mosaic virus (BYMV), não transmitido por afídeos

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, 1996.Bean yellow mosaic virus (BYMV) é uma espécie do gênero Potyvirus, da família Potyviridae. Esses vírus são transmitidos por afídeos de maneira não persistente, exigindo para tal a presença de duas proteínas codificadas pelo vírus: a proteína da capa (CP) e a proteinase “helper component” (HC-Pro). Mutações em alguns poucos blocos de aminoácidos nestas duas proteínas estão relacionadas com a perda da transmissão de potyvirus por afídeos. Mutações no “triplet” altamente conservado D/NAG, localizado na região N-terminal da CP, e nos blocos KITC e PTK, localizados respectivamente no N-terminal e no C-terminal de HC-Pro, foram associadas com esta perda. Uma estirpe necrótica de BYMV, denominada BYMVn, não foi transmitida por 15 diferentes espécies de afídeos. Ensaios de transmissão dependente, utilizando-se BCMV como vírus auxiliar, e com dez diferentes fontes de inóculo também foram negativos. Visando elucidar a base molecular da não transmissão de BYMVn, a porção Nterminal da CP foi caracterizada. RNA total de planta infectada com BYMVn foi extraído e utilizado como molde na obtenção de cDNA. Este último foi submetido à amplificação por PCR e o produto obtido (414pb da região N-terminal da CP) foi ligado ao plasmídio pGemT Vector. O clone obtido foi sequenciado, permitindo a leitura de 170 nucleotídeos da região 5’ e 208 da região 3’ do fragmento. O “triplet” NAG da CP mostrou-se conservado, não podendo ser associado a não transmissão de BYMVn por afídeos. Análise molecular subsequente de HC-Pro poderia mostrar se mutações nos blocos KITC e/ou PTK estariam, portanto, envolvidas na perda da capacidade de transmissão de BYMVn pelo inseto vetor. Como aproximadamente 40% da CP, representando a metade N-terminal, de BYMVn foi sequenciada, os valores de homologia encontrados devem representar as diferenças reais existentes entre a CP deste isolado e as dos demais já caracterizados. Diferenças variando de 18,3 à 29,6% de nucleotídeos e de 12,0 à 25,5% de aminoácidos demonstram que mesmo dentro de uma espécie de potyvirus, variações significativas nas seqüências de nucleotídeos e de aminoácidos podem ser encontradas, refletindo as diferenças biológicas observadas entre este e os demais isolados. A análise dos valores de identidade e similaridade da seqüência de aminoácidos entre BYMVn e os demais isolados demonstrou que o isolado necrótico BYMVn é mais relacionado com a estirpe S. 62 Estudos adicionais de western blot mostraram uma massa molecular da CP de BYMVn de cerca de 30 kDa, sendo que a proteína manteve sua reatividade sorológica. O perfil peptídico da CP, obtido através de digestão tríptica e HPLC, mostrou que esta técnica pode ser usada na diferenciação de espécies de potyvirus, mas não permite localizar diferenças menores na seqüência de aminoácidos, como as responsáveis pela transmissão por afídeos.Bean yellow mosaic virus is a virus species identified as a member of the genus Potyvirus within the Potyviridae family. These viruses are aphid transmitted in a nonpersistent manner. The transmission depends upon both virus encoded proteins: the coat protein (CP) and the heiper component proteinase (HC-Pro). Mutational studies in some of the amino acids domains demonstrated that both proteins are related with the loss of transmission of these viruses by aphids. Mutations on the highly conserved triplet D/NAG, located at the CP N-terminal, and on KITC and PTK boxes, located at HC-Pro N-terminal and C-terminal respectively, were associated with the lack of vector transmissibility. Fifteen different species of aphids were tested for the transmission of a BYMV necrotic strain, denoted BYMVn. None of them was able to transmit this virus strain. Dependent transmission assay, using BCMV as helper virus, was also negative. Ten different inocullum sources for virus acquisition by the aphid were also tested and no virus transmission was obtained. In order to elucidate the molecular basis of this non aphid-transmissibility of the viruses, part of the N-terminal of the BYMVn coat protein was sequenced. Total RNA was extracted from plants infected with BYMVn and used as template for cDNA synthesis. This cDNA was used as template for amplification by PCR and the product (414 bp from the CP N-terminal) was cloned in the pGemT Vector and sequenced. A nucleotide sequence of 170 bases from 5’ region and 208 base from 3’ region of that fragment was obtained The triplet NAG showed to be conserved in the BYMVn coat protein and it can not be associated to inability of the virus to be aphid transmitted. Further molecular analysis of the HC-Pro may show if mutations on KITC or PTK boxes are involved on the BYMVn transmissibility by aphids. Approximately 40% of N-terminal coat protein of BYMVn was sequenced. The similarity values found may correspond to the real difference between the BYMVn CP and the other previously isolates characterize. Differences ranging from 18,3 - 29,6% of nucleotides sequences, and 12 - 25,5% at amino acids levei demonstrate that even in the some species of potyvirus, significant variations in the nucleotides and amino acids sequences can be found and it can express the biological differences observed between BYMVn and the other BYMV isolates. Analysis of the amino acid similarities and identities between BYMVn and the other isolates demonstrated that the necrotic isolate is closer related to the S strain. 65 Additional western blot studies showed that CP of BYMVn has a molecular welght of about 30 kDa, showing no changes In its serologlcal reactivlty. The HPLC peptlde profile of tryptlc dlgest CP showed that this technlque can be used to separate spoclos wlthln tho potyvirus gonus, but it doos not allow us to locnlo smoll dlfferoncos In the amino acld sequence responslble for aphid transmission

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Begomovírus em soja no Brasil e ferramentas moleculares para sua identificação

CNP

Principais dificuldades e obstáculos enfrentados pela comunidade surda no acesso à saúde: uma revisão integrativa de literatura

RESUMO Buscou-se identificar na literatura os principais obstáculos e dificuldades enfrentadas por pessoas surdas quanto ao acesso à saúde. Trata-se de uma revisão integrativa de literatura, considerando estudos publicados entre 2006 e 2016, utilizando combinações de descritores controlados. As bases de dados virtuais utilizadas foram: LILACS, PUBMED e SciELO, incluindo artigos publicados em Inglês, Português e Espanhol. A amostra final foi composta por 24 artigos, selecionados após análise dos títulos, resumos e textos na íntegra. Os estudos selecionados foram categorizados quanto às principais temáticas e dificuldades enfrentadas pela comunidade surda, sendo principalmente relacionadas à barreira comunicacional existente entre ouvintes e surdos. Tal fato culmina em interferências na relação profissional-paciente, compreensão deficitária das pessoas surdas quanto ao processo saúde-doença e as dificuldades de integração da pessoa surda na comunidade. Na maioria dos estudos analisados, evidenciou-se que as dificuldades enfrentadas pelas pessoas surdas quando buscam atendimento em saúde são ligadas à comunicação, bem como desconhecimento de Língua Brasileira de Sinais (LIBRAS) por grande parte dos profissionais de saúde. Além disso, também há a necessidade de familiar ou intérprete presente durante a consulta e a falta de compreensão de grande parte da comunidade surda como sujeitos bilíngues e multiculturais

Anti-Diabetic Effects of the Ethyl-Acetate Fraction of Trichilia catigua in Streptozo-tocin-Induced Type 1 Diabetic Rats

Background/Aims: Trichilia catigua A. Juss., known as “catuaba” in Brazil, has been popularly used as a tonic for fatigue, impotence and memory deficits. Previously, our group demonstrated that the ethyl-acetate fraction (EAF) of T. catigua has antioxidant and anti-inflammatory effects. The present study evaluated the anti-diabetic activity of EAF in type 1 diabetic rats. Methods: Male Wistar rats were divided into four groups (N: non-diabetic group, D: type 1 diabetic group, NC: non-diabetic + EAF group and DC: type 1 diabetic + EAF group). The latter two groups were treated with 200 mg/kg EAF. Type 1 diabetes was induced by intravenous streptozotocin (STZ) injection (35 mg/kg). Starting two days after STZ injection, EAF was administered daily by gavage for 8 weeks. Results: EAF attenuated body mass loss and reduced food and water intake. EAF improved hyperglycaemia and other biochemical parameters, such as alkaline phosphatase (ALP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Furthermore, the number of pancreatic β-cells and the size of the islets had increased by β-cell proliferation in the DC group. EAF promoted reduction in kidney tissue damage in STZ-induced diabetic rats by reduction of renal fibrosis. Conclusion: The present study showed that EAF improves glucose homeostasis and endocrine pancreas morphology and inhibits the development of diabetic nephropathy in STZ-induced diabetic rats