Estudo comparativo entre ovitrampa e o método LIRAa para avaliação da presença de Aedes aegypti (Diptera:Culicidae) em Pedro II, Piauí, Brasil / Comparative study between ovitraps and LIRAa method for evaluating the presence of Aedes aegypti (Diptera:Culicidae) in Pedro II, Piauí, Brazil

O aumento no número de casos de dengue, Chikungunya e Zika vírus se deve a vários fatores, como aumento da urbanização, abastecimento de água irregular e controle ineficaz do vetor primário Aedes aegypti. Assim, estratégias de monitoramento desses vetores são necessárias para redução da circulação viral. O objetivo desse estudo foi avaliar comparativamente, o Levantamento Rápido do índice de Infestação por Ae. aegypti (LIRAa) e a ovoposição em armadilhas (ovitrampa) na cidade de Pedro II, PI- Brasil em três bairros: Boa Esperança, Cristo Rei e Vila Kolping.  As ovitrampas foram elaboradas com pote plástico escuro, contendo no seu interior água, uma palheta e o larvicida Pyriproxifen. No período de 2019 e 2020, colocou-se 31 ovitrampas em pontos estratégicos para contagem e identificação dos ovos presentes na palheta e a partir dos dados obtidos foi possível o cálculo dos Índices de Positividade de Ovitrampa (IPO) e Índices de Densidade de Ovos (IDO). Os dados obtidos foram comparados com o LIRAa realizado em 2019 nos meses de maio, agosto e outubro.  Coletou-se 23.704 ovos. No bairro Boa Esperança foram 9.020 ovos (38,1%) com IPO = 68,9% e IDO = 222,8. No Cristo Rei foram 9.659 ovos (40,7%), IPO = 72,4% e IDO = 109,6. No Vila Kolping, 5.025 ovos (21,2%), IPO = 47,4% e IDO = 81,3. Os resultados mostraram que o IPO variou muito (27,2% a 100%) entre os bairros amostrados, o que demonstra a grande flutuabilidade populacional do vetor. De acordo com o LIRAa, os bairros ofereceram risco alto de infestação do vetor, especialmente no mês de maio. No entanto, no mês de outubro os índices aferidos pelo LIRAa tiveram o valor entre 0,8% e 1,3% e os ovos ainda estavam com a densidade alta, como é o caso do bairro Boa Esperança com 203,6 de IDO.  O grupo de depósitos que predominou foi o A2, caracterizado por grandes reservatórios de água, vasos/frascos com água, pratos, garrafas e outros. Os resultados da pesquisa indicam que o monitoramento por ovitrampas e o método LIRAa são atividades complementares e instrumentos de grande utilidade para a vigilância vetorial, permitindo maior precisão na tomada de decisões

Antimicrobial and Cytotoxic Properties of Extracts from Plants Traditionally Used in North-East Brazil

The north-eastern region of Brazil is home to communities of diverse ethnic origins that still depend significantly on folk medicine, with emphasis on plant extracts. The present work aims at investigating medicinal plants used in the traditional medicine of north-eastern Brazil with an assessment of the antimicrobial profile of their extracts. The antimicrobial activity of 12 extracts from 11 plant species from eight higher plant families traditionally used was evaluated against three human pathogens (Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae) using the Agar Disk Diffusion and Broth Microdilution assays. The cytotoxic effects were evaluated on human keratinocytes. A hydroalcoholic extract from Anadenanthera colubrina presented the most promising in vitro antimicrobial activity against S.aureus associated with low cytotoxicity towards human keratinocytes. The information gathered in the present study represents a starting point for further research aiming at providing scientific evidence to the empirical usage of medicinal plants in traditional practices

Construção de um mapa genético para feijão-caupi com marcadores moleculares ISSR, DAF E CAPS

A cultura do feijão-caupi é de grande importância econômica no Brasil, sendo a região Nordeste a principal produtora. A baixa resistência aos principais patógenos é um dos fatores limitantes para a competitividade brasileira da cultura no mercado nacional e internacional. Uma das doenças mais importantes é a virose, causado pelo Cowpea severe mosaic virus - CPSMV. O controle de CPSMV pode ser obtido com o uso de inseticidas no combate aos insetos vetores. Contudo, é necessário aumentar o emprego de medidas mais econômicas e que não agridam o ambiente, com a utilização de cultivares resistentes. Atualmente, o melhoramento genético de plantas está utilizando ferramentas que possibilitam a obtenção de resultados mais rápidos e precisos. Dentre elas podem-se citar os mapas genéticos, obtidos por meio de marcadores moleculares do tipo ISSR, DAF e CAPS, os quais apresentam elevado polimorfismo. Este trabalho buscou a construção de um mapa genético, visando o mapeamento de genes de resistência a doenças em feijão-caupi. Pelo cruzamento dos parentais contrastantes BR 14-Mulato e IT85F-2687 obteve-se 92 linhas endogâmicas recombinantes F6-7 que foram mecanicamente inoculadas e avaliadas quanto à reação ao Cowpea severe mosaic virus CPSMV. O programa MapMarker 2.0 foi utilizado para a construção do mapa adotando-se LOD 2.0, freqüência de recombinação r<0.40 e função de mapeamento de Kosambi. Foi gerado o mapa com 6 marcadores DAF, 27 ISSR e 6 CAPS distribuídos em 11 grupos de ligação (GL), cobrindo 492,128 cM e uma distância média entre marcadores de 16,9 cM. A reação fenotípica ao CPSMV foi codificada como um marcador e mapeado como característica qualitativa, sendo localizado a uma distância genética estimada em 28,7 cM do marcador ISSR-878. Contudo, esta distância entre a marca e o gene não permite ainda o uso de seleção assistida. O desenvolvimento de mapas de ligação para o feijão-caupi é o primeiro passo na integração de biotecnologia nos programas de melhoramento genético visando a introgressão de genes de resistênci

Plants Defense-related Cyclic Peptides: Diversity, Structure and Applications

Plant growth is prone to several unfavorable factors that may compromise or impair development and survival, including abiotic or biotic stressors. Aiming at defending themselves, plants have developed several strategies to survive and adapt to such adversities. Cyclotides are a family of plant-derived proteins that exhibit a diverse range of biological activities including antimicrobial and insecticidal activities that actively participate in plant defense processes. Three main categories of peptides have been described: (i) Cyclotides (ii) Sunflower Trypsin Inhibitor (SFTI) and (iii) peptides MCoTI-I and II, from Momordica cochinchinensis. They comprise proteins of approximately 30 amino acids, containing a head-to-tail cyclized backbone, with three disulfide bonds configured in a cystine knot topology, therefore bearing greater peptide stability. Given their features and multifunctionality, cyclotides stand out as promising sources for the discovery of new antimicrobial agents. The present review describes cyclotide occurrence, abundance and action in plants, also their and evolution. Considerations regarding their use in the context of biomedical and agronomical sciences uses are also presented

Plant Elite Squad: First Defense Line and Resistance Genes - Identification, Diversity and Functional Roles

Plants exhibit sensitive mechanisms to respond to environmental stresses, presenting some specific and non-specific reactions when attacked by pathogens, including organisms from different classes and complexity, as viroids, viruses, bacteria, fungi and nematodes. A crucial step to define the fate of the plant facing an invading pathogen is the activation of a compatible Resistance (R) gene, the focus of the present review. Different aspects regarding R-genes and their products are discussed, including pathogen recognition mechanisms, signaling and effects on induced and constitutive defense processes, splicing and post transcriptional mechanisms involved. There are still countless challenges to the complete understanding of the mechanisms involving R-genes in plants, in particular those related to the interactions with other genes of the pathogen and of the host itself, their regulation, acting mechanisms at transcriptional and post-transcriptional levels, as well as the influence of other types of stress over their regulation. A magnification of knowledge is expected when considering the novel information from the omics and systems biology

Resistance (R) Genes: Applications and Prospects for Plant Biotechnology and Breeding

The discovery of novel plant resistance (R) genes (including their homologs and analogs) opened interesting possibilities for controlling plant diseases caused by several pathogens. However, due to environmental pressure and high selection operated by pathogens, several crop plants have lost specificity, broad-spectrum or durability of resistance. On the other hand, the advances in plant genome sequencing and biotechnological approaches, combined with the increasing knowledge on R-genes have provided new insights on their applications for plant genetic breeding, allowing the identification and implementation of novel and efficient strategies that enhance or optimize their use for efficiently controlling plant diseases. The present review focuses on main perspectives of application of R-genes and its co-players for the acquisition of resistance to pathogens in cultivated plants, with emphasis on biotechnological inferences, including transgenesis, cisgenesis, directed mutagenesis and gene editing, with examples of success and challenges to be faced

Cowpea and abiotic stresses: identification of reference genes for transcriptional profiling by qPCR

Abstract Background Due to cowpea ability to fix nitrogen in poor soils and relative tolerance to drought and salt stresses, efforts have been directed to identifying genes and pathways that confer stress tolerance in this species. Real-time quantitative PCR (qPCR) has been widely used as the most reliable method to measure gene expression, due to its high accuracy and specificity. In the present study, nine candidate reference genes were rigorously tested for their application in normalization of qPCR data onto roots of four distinct cowpea accessions under two abiotic stresses: root dehydration and salt (NaCl, 100 mM). In addition, the regulation of four target transcripts, under the same referred conditions was also scrutinized. Results geNorm, NormFinder, BestKeeper, and ΔCt method results indicated a set of three statistically validated RGs for each stress condition: (I) root dehydration (actin, ubiquitin-conjugating enzyme E2 variant 1D, and a Phaseolus vulgaris unknown gene—UNK), and (II) salt (ubiquitin-conjugating enzyme E2 variant 1D, F-box protein, and UNK). The expression profile of the target transcripts suggests that flavonoids are important players in the cowpea response to the abiotic stresses analyzed, since chalcone isomerase and chalcone synthase were up-regulated in the tolerant and sensitive accessions. A lipid transfer protein also participates in the cowpea tolerance mechanisms to root dehydration and salt stress. The referred transcript was up-regulated in the two tolerant accessions and presented no differential expression in the sensitive counterparts. Chitinase B, in turn, generally related to plant defense, was an important target transcript under salt stress, being up-regulated at the tolerant, and down-regulated in the sensitive accession. Conclusions Reference genes suitable for qPCR analyses in cowpea under root dehydration and salt stress were identified. This action will lead to a more accurate and reliable analysis of gene expression on this species. Additionally, the results obtained in this study may guide future research on gene expression in cowpea under other abiotic stress types that impose osmotic imbalance. The target genes analyzed, in turn, deserve functional evaluation due to their transcriptional regulation under stresses and biotechnological potential