143 research outputs found

    Avaliação dos danos causados por (Westwood, 1837) (Hemiptera, Pentatomidae), em diferen tes niveis e épocas de infestação, na qualidade da semente de soja (\u3ci\u3eGlycine max\u3c/i\u3e (L.) Merrill)

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    Assessment of soybean seed quality in relation to the damage caused by Piezodorus guildinii (Westwood, 1837) (Hemiptera, Pentatornidae) at various infestation levels and at diferent stages of soybean development (Glycine max (L.) Merrill). Stinkbug effect on soybean seed quality was studied. Field tests were carried out in Guaiba, Rio Grande do Sul, 1974/75. Soybean plants were artificially infested at various densities of Piezodorus guildinii (Westwood, 1837) per 0.5m of row and at different stages of soybean development by means of isolation cages. Stinkbug infestations restricted from full bloom up to the beginning of pod formation do not result in reduction of seed quality. However, infestation during full bloom up to the complete physiological maturity of the seed or restricted to the seed development stage do result in reduction of seed quality in terms of percentage damaged seeds, oil and protein content, and seed germination. Similar results were obtained with higher infestation leveIs during the physiological maturation of the seeds. A qualidade da semente de soja pode ser afetada pela ação dos insetos da família Pentatomidae que apresentam uma preferência pelas estruturas frutíferas de sua planta hospedeira, causando danos considerãveis ã mesma

    Incidence of natural control agents of the velvetbean caterpillar and response of its predators to insecticide treatments in Brazilian soybean fields

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    Lagartas de Anticarsia gemmatalis Hubner foram coletadas em soja (Glycine max (L.) Merrill) para determinar os níveis populacionais e a porcentagem de infecção pelo fungo-Nomuraea rileyi (Farlow) Samson. Os níveis populacionais de larvas e adultos do predador Colosoma argentatus granulatum (Perty) foram determinados utilizando armadilhas de solo. Foi estudada a relação entre a ressurgência de A. gemmatalis e os níveis populacionais dos predadores C. argentatus granulatum, Geocoris spp. e Nabis spp. sob influência de inseticidas. A infestação pelo fungo N. rileyi começou em fevereiro, durante o estágio de desenvolvimento dos legumes quando a terceira geração de lagartas alcançou o seu pico. Três semanas mais tarde 100% das lagartas observadas sobre as folhas estavam infectadas pelo fungo. A atividade de C argentatus granulatum coincidiu com o pico da terceira geração de A. gemmatalis. As populações de Geocoris spp. e Nabis spp. foram severamente afetadas com as aplicações de monocrotofos e metilparation, mas a aplicação diflubenzuron, um inibidor da formação de quitina, aparentemente não provocou efeito deletério.Larvae of the velvetbean caterpillar Anticarsia gemmatalis Hubner were collected from soybean (Glycine max (L.) Merrill) to determine their population levels and percentage of infection by the fungus, Normuraea rileyi (Farlow) Samson. Seasonal population levels of larvae and adults of the carabid predator, Calosoma argentatus granulatum (Perty) were determined by pitfall trap collections. The relationship between resurgence of Anticarsia and populations of Calosoma, geocorids, and nabids as influenced by insecticides was studied. Fungus attack began in February during the pod development stage when the third generation of Anticarsia larvae were reaching a peak and 100% of larvae observed on foliage were infected three weeks later. Activity of Colosoma coincided closely with population levels of the third generation of Anticarsia. Geocorid and nabid populations were severely affected by monocrotophos and methyl parathion treatments whereas diflubenzuron, a chitin inhibitor, had no apparent deleterious effect

    A new species of Eclipta Bates, 1873 from Brazil (Coleoptera, Cerambycidae) in honor of the late Ubirajara Ribeiro Martins de Souza

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    A new species of Eclipta Bates, 1873 from Brazil (São Paulo), E. birai, is described and illustrated. A tribute to the late Ubirajara Ribeiro Martins de Souza is provided

    Neuregulin-1 Regulates Cell Adhesion via an ErbB2/Phosphoinositide-3 Kinase/Akt-Dependent Pathway: Potential Implications for Schizophrenia and Cancer

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    Neuregulin-1 (NRG1) is a putative schizophrenia susceptibility gene involved extensively in central nervous system development as well as cancer invasion and metastasis. Using a B lymphoblast cell model, we previously demonstrated impairment in NRG1alpha-mediated migration in cells derived from patients with schizophrenia as well as effects of risk alleles in NRG1 and catechol-O-methyltransferase (COMT), a second gene implicated both in schizophrenia susceptibility and in cancer.Here, we examine cell adhesion, an essential component process of cell motility, using an integrin-mediated cell adhesion assay based on an interaction between ICAM-1 and the CD11a/CD18 integrin heterodimer expressed on lymphoblasts. In our assay, NRG1alpha induces lymphoblasts to assume varying levels of adhesion characterized by time-dependent fluctuations in the firmness of attachment. The maximum range of variation in adhesion over sixty minutes correlates strongly with NRG1alpha-induced migration (r(2) = 0.61). NRG1alpha-induced adhesion variation is blocked by erbB2, PI3K, and Akt inhibitors, but not by PLC, ROCK, MLCK, or MEK inhibitors, implicating the erbB2/PI3K/Akt1 signaling pathway in NRG1-stimulated, integrin-mediated cell adhesion. In cell lines from 20 patients with schizophrenia and 20 normal controls, cells from patients show a significant deficiency in the range of NRG1alpha-induced adhesion (p = 0.0002). In contrast, the response of patient-derived cells to phorbol myristate acetate is unimpaired. The COMT Val108/158Met genotype demonstrates a strong trend towards predicting the range of the NRG1alpha-induced adhesion response with risk homozygotes having decreased variation in cell adhesion even in normal subjects (p = 0.063).Our findings suggest that a mechanism of the NRG1 genetic association with schizophrenia may involve the molecular biology of cell adhesion

    Induction of the GABA Cell Phenotype: An In Vitro Model for Studying Neurodevelopmental Disorders

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    Recent studies of the hippocampus have suggested that a network of genes is associated with the regulation of the GAD67 (GAD1) expression and may play a role in γ-amino butyric acid (GABA) dysfunction in schizophrenia (SZ) and bipolar disorder (BD). To obtain a more detailed understanding of how GAD67 regulation may result in GABAergic dysfunction, we have developed an in vitro model in which GABA cells are differentiated from the hippocampal precursor cell line, HiB5. Growth factors, such as PDGF, and BDNF, regulate the GABA phenotype by inducing the expression of GAD67 and stimulating the growth of cellular processes, many with growth cones that form appositions with the cell bodies and processes of other GAD67-positive cells. These changes are associated with increased expression of acetylated tubulin, microtubule-associated protein 2 (MAP2) and the post-synaptic density protein 95 (PSD95). The addition of BDNF, together with PDGF, increases the levels of mRNA and protein for GAD67, as well as the high affinity GABA uptake protein, GAT1. These changes are associated with increased concentrations of GABA in the cytoplasm of “differentiated” HiB5 neurons. In the presence of Ca2+ and K+, newly synthesized GABA is released extracellularly. When the HiB5 cells appear to be fully differentiated, they also express GAD65, parvalbumin and calbindin, and GluR subtypes as well as HDAC1, DAXX, PAX5, Runx2, associated with GAD67 regulation. Overall, these results suggest that the HiB5 cells can differentiate into functionally mature GABA neurons in the presence of gene products that are associated with GAD67 regulation in the adult hippocampus
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