Cytotoxicity analysis of three Bacillus thuringiensis Subsp. israelensis d-Endotoxins towards insect and mammalian cells

Three members of the d-endotoxin group of toxins expressed by Bacillus thuringiensis subsp. israelensis, Cyt2Ba, Cry4Aa and Cry11A, were individually expressed in recombinant acrystalliferous B. thuringiensis strains for in vitro evaluation of their toxic activities against insect and mammalian cell lines. Both Cry4Aa and Cry11A toxins, activated with either trypsin or Spodoptera frugiperda gastric juice (GJ), resulted in different cleavage patterns for the activated toxins as seen by SDS-PAGE. The GJ-processed proteins were not cytotoxic to insect cell cultures. On the other hand, the combination of the trypsinactivated Cry4Aa and Cry11A toxins yielded the highest levels of cytotoxicity to all insect cells tested. The combination of activated Cyt2Ba and Cry11A also showed higher toxic activity than that of toxins activated individually. When activated Cry4Aa, Cry11A and Cyt2Ba were used simultaneously in the same assay a decrease in toxic activity was observed in all insect cells tested. No toxic effect was observed for the trypsin-activated Cry toxins in mammalian cells, but activated Cyt2Ba was toxic to human breast cancer cells (MCF-7) when tested at 20 mg/mL

First association of scale insects (Hemiptera: Diaspididae) with \u3ci\u3eSalacia crassifolia\u3c/i\u3e (Mart. Ex Schult.) G. Don. (Celastraceae)

Salacia crassifolia (Mart. ex Schult.) G.Don., (Celastraceae) is a native species of shrub/tree highly ap­preciated in Brazil for its fruits and medicinal properties. Scale insects have never been reported associated with S. crassifolia; nevertheless, this paper describes the occurrence of two diaspidids on S. crassifolia leaves in Brazil. Three mature trees were inspected in February and March 2018 and scale insect samples were collected and pre­served in 70% alcohol, then mounted and identified under an optical microscope. Two species of scale insects were found associated with this plant, Pseudoparlatoria argentata Hempel and Melanaspis aristotelesi Lepage and Gi­annotti, both from the family Diaspididae (Hemiptera). The three observed trees were infested by the diaspidids, with some leaves completely colonized by both species. This is the first reported occurrence of P. argentata and M. aristotelesi in plants of the Celastraceae family. It is also the first report of these insects in the Distrito Federal, Brazil, expanding the distribution and hosts in native plant species of the Cerrado biome

First Report of Eutetranychus banksi (McGregor) on Mahogany (Swietenia macrophylla King)

Texas citrus mite, Eutetranychus banksi (McGregor) (Acari: Tetranychidae: Tetranychinae), considered a serious pest of the citrus crop in some countries, is reported for the first time on mahogany seedlings (Swietenia macrophylla King, Meliaceae) in Brazil, causing foliar tanning with chlorotic spots and premature fall of leaves

Identificação de biótipos B, Q e nativo brasileiro do complexo da espécie Bemisia tabaci por meio de marcadores Scar

O objetivo deste trabalho foi desenvolver marcadores "sequence-characterized amplified region" (Scar) para identificar os biótipos B, Q e nativo brasileiro da mosca-branca [Bemisia tabaci (Hemiptera: Aleyrodidae)]. Produtos de amplificação de DNA polimórfico amplificado ao acaso (RAPD), exclusivos aos biótipos B e nativo brasileiro, foram selecionados após análise de 12.000 amostras, para desenhar um conjunto de iniciadores específicos de Scar. Os marcadores Scar BT-B1 e BT-B3, usados para detectar o biótipo B, produziram fragmentos de PCR de 850 e 582 pb, respectivamente. O marcador Scar BT-BR1, utilizado para identificar o biótipo brasileiro, produziu um fragmento de PCR de 700 pb. Os marcadores Scar foram testados contra o biótipo Q, e um fluxograma foi proposto para indicar os passos para tomada de decisão sobre quando usar esses iniciadores, para discriminar corretamente os biótipos. Este procedimento permitiu identificar os biótipos que ocorrem em amostras de campo, como o biótipo B. O conjunto de iniciadores utilizados permitiu discriminar os biótipos B, Q e nativo brasileiro de B. tabaci. Esses iniciadores podem ser utilizados com sucesso para identificar o biótipo B de B. tabaci em amostras de campo, e mostram apenas um biótipo específico presente em todas as culturas.The objective of this work was to develop sequence-characterized amplified region (Scar) markers to identify the B, Q, and native Brazilian biotypes of the sweet potato whitefly [Bemisia tabaci (Hemiptera: Aleyrodidae)]. Random amplified polymorphic DNA (RAPD) amplification products, exclusive to the B and Brazilian biotypes, were selected after the analysis of 12,000 samples, in order to design a specific Scar primer set. The BT-B1 and BT-B3 Scar markers, used to detect the B biotype, produced PCR fragments of 850 and 582 bp, respectively. The BT-BR1 Scar marker, used to identify the Brazilian biotype, produced a PCR fragment of 700 bp. The Scar markers were tested against the Q biotype, and a flowchart was proposed to indicate the decision steps to use these primers, in order to correctly discriminate the biotypes. This procedure allowed to identify the biotypes that occur in field samples, such as the B biotype. The used set of primers allowed to discriminate the B, Q, and native Brazilian biotypes of B. tabaci. These primers can be successfully used to identify the B biotype of B. tabaci from field samples, showing only one specific biotype present in all cultures

Ocorrência da cochonilha Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) em mudas de mogno (Swietenia macrophylla King)

Resumo. Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) é relatada pela primeira vez associada ao mogno brasileiro, Swietenia macrophylla King (Meliaceae). Infestações deste pseudococcídeo foram observadas sobre folhas e ramos de mudas do mogno cultivadas em casa de vegetação, em Brasília, Distrito Federal, Brasil. O controle da cochonilha foi realizado manualmente e/ou com aplicação de solução de água com detergente neutro a 10%. Occurrence of the mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) on mahogany seedlings (Swietenia macrophylla King) Abstract. Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) is reported for the first time on brazilian mahogany, Swietenia macrophylla King (Meliaceae). Infestations of this Pseudococcidae were observed on leafs and branches of mahogany seedlings cultivated in a greenhouse, in Brasilia, Federal District, Brazil. The control of the mealybug was realized manually and/or with application of water solution with 10% of neutral detergent

Marcadores mitocondriais para diferenciar populações de Spodoptera frugiperda associadas às culturas de milho e algodão

The objective of this work was to analyze the genetic variability of Spodoptera frugiperda (Lepidoptera: Noctuidae) populations collected from corn and cotton crops in Brazil. The samples were analyzed by DNA markers. The dendrogram produced by the 20 RAPD primers evaluated showed a correlation between genetic profile and feeding behavior. The analysis of the mitochondrial ND1 gene allowed identifying the insect populations in both crops, and, in corn, in several geographical regions. The presented strategy allows the identification of Spodoptera frugiperda populations associated with corn and cotton crops.O objetivo deste trabalho foi avaliar a variabilidade genética de populações de Spodoptera frugiperda (Lepidoptera: Noctuidae) coletadas nas culturas de milho e algodão do Brasil. As amostras foram analisadas por marcadores de DNA. O dendrograma produzido pelos 20 iniciadores de RAPD avaliados revelou correlação entre o perfil genético e o comportamento de alimentação. A análise do gene ND1 mitocondrial permitiu identificar populações do inseto em ambas as culturas, e, em milho, em várias regiões geográficas. A estratégia apresentada permite a identificação de populações de Spodoptera frugiperda associadas às culturas de milho e algodão

Selection and characterization of Bacillus thuringiensis strains effective to control the diamondback moth Plutella xylostella

O objetivo deste trabalho foi selecionar e caracterizar, no Banco de Germoplasma de Bacillus spp., da Empresa Brasileira de Pesquisa Agropecuária, as estirpes de Bacillus thuringiensis mais tóxicas à Plutella xylostella, por métodos morfológicos, bioquímicos e moleculares. Das 203 estirpes testadas, sete causaram 100% de mortalidade e foram semelhantes à estirpe padrão utilizada, B. thuringiensis subsp. kurstaki. Elas apresentaram proteínas de 130 kDa e 65 kDa, presença de genes cry1 e cry2 e cristais bipiramidais, cubóides e redondos. As estirpes selecionadas oferecem novas perspectivas de controle de P. xylostella.The aim of this work was to select and characterize the most toxic Bacillus thuringiensis strains, from the Germplasm Bank of Bacillus spp. of Empresa Brasileira de Pesquisa Agropecuária, against Plutella xylostella. Strains were characterized by morphological, biochemical and molecular methods. It was observed that seven out of the 203 strains tested showed high toxicity compared to the standard used B. thuringiensis subsp. kurstaki (HD-1), which showed 100% mortality. Selected strains showed features described for lepidoptera regarding the protein of 130 kDa and 65 kDa; profile and features were obtained through the PCR reactions, making possible to identify the presence of cry1 and cry2 genes. Moreover, the scanning electron microscopy showed the bipiramydal, cubed and round crystal forms. The selected strains offer new perspectives to control P. xylostella

Estirpes de Bacillus thuringiensis efetivas contra insetos das ordens Lepidoptera, Coleoptera e Diptera

The aim of this work was to select among 300 strains of Bacillus thuringiensis those which are simultaneously effective against larvae of Spodoptera frugiperda J.E. Smith and Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae), Anthonomus grandis Boheman (Coleoptera: Curculionidae), Aedes aegypti Linnaeus and Culex quinquefasciatus Say (Diptera: Culicidae). Two strains of B. thuringiensis were selected, S234 and S997, which presented activity against those three insect orders. Both strains were characterized by morphological, biochemical and molecular methods. They have presented two main proteins with 130 and 65 kDa, polimerase chain reaction products with expected sizes for detection of the genes cry1Aa, cry1Ab, cry1Ac, cry1B and cry2 and bipiramidal, cubical and spherical crystals.O objetivo deste trabalho foi selecionar entre 300 estirpes de Bacillus thuringiensis as efetivas simultaneamente contra larvas de Spodoptera frugiperda J.E. Smith e Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae), Anthonomus grandis Boheman (Coleoptera: Curculionidae), Aedes aegypti Linnaeus e Culex quinquefasciatus Say (Diptera: Culicidae). Foram selecionadas duas estirpes de B. thuringiensis, denominadas S234 e S997, que apresentaram atividade contra as três ordens de insetos. As estirpes foram caracterizadas por métodos morfológicos, bioquímicos e moleculares. As mesmas apresentaram duas proteínas principais de 130 e 65 kDa, produtos de reação em cadeia da polimerase de tamanho esperado para a detecção dos genes cry1Aa, cry1Ab, cry1Ac, cry1B e cry2 e cristais bipiramidais, cubóides e esféricos