4,507 research outputs found
Tolerância de Noctuideos a proteína CRY1AC expressa no algodão Bollgard.
A introdução da soja Bt no cenário agrícola nacional é acompanhada pela preocupação da seleção de populações resistentes de lepidópteros suscetíveis e tolerantes às toxinas de Bacillus thuringiensis (Bt). A pressão de seleção poder ser exercida pela soja-Bt, assim como por o algodão-Bt, que expressam a mesma toxina, Cry1Ac. Portanto a avaliação da suscetibilidade/tolerância das diferentes espécies de noctuideos é de fundamental importância para definir estratégias para monitorar e prevenir os possíveis casos de resistência a Cry1Ac. Folhas de algodão (Delta Opal e da cultivar convencional NuOpal) provenientes de plantas com 30 dias de germinadas foram desidratadas, moídas e incorporadas na proporção de 2g de peso seco em 40 ml de dieta de Greene. A dieta com e sem tecidos de algodão foi oferecida como alimento para lagartas de Pseudoplusia includens, Spodoptera cosmioides e S. eridania e uma população de Anticarsia gemmatalis resistente e duas populações suscetíveis (uma população de laboratório e outra de Cruz Alta, RS) ao inseticida biológico a base de Bt, Dipel. A sobrevivência de lagartas de A. gemmatalis suscetíveis e resistentes (taxa de resistência = 103x) ao Dipel foi afetada pela presença de algodão convencional na dieta. Mas também foi significativamente afetada pela presença da toxina Cry1Ac. A sobrevivência de P. includens foi menos afetada que A. gemmatalis pela presença da toxina na dieta e também foi afetada pela presença das folhas de algodão convencional. A sobrevivência das espécies de Spodoptera não foi afetada pela presença da toxina na dieta. O ganho de peso das espécies de Spodoptera foi menos afetado pela presença da toxina, sendo esse efeito negativo mais pronunciado em A. gemmatalis, tanto nas populações suscetíveis como na resistente. As populações de A. gemmatalis provenientes de Cruz Alta encontravam-se na 3ª geração, provavelmente, menos adaptadas às condições de criação em laboratório resultando em menor sobrevivência. S. eridania, S. cosmioides e P. includens, foram as espécies mais tolerantes a toxina expressa em folhas de algodão. Lagartas de A. gemmatalis resistentes a uma formulação comercial de B. thuringiensis foram suscetíveis a toxina Cry1Ac.SICONBIOL 2011
Introduction: Examined Live – An Epistemological Exchange Between Philosophy and Cultural Psychology on Reflection
Besides the general agreement about the human capability of reflection, there is a large area of disagreement and debate about the nature and value of “reflective scrutiny” and the role of “second-order states” in everyday life. This problem has been discussed in a vast and heterogeneous literature about topics such as epistemic injustice, epistemic norms, agency, understanding, meta-cognition etc. However, there is not yet any extensive and interdisciplinary work, specifically focused on the topic of the epistemic value of reflection. This volume is one of the first attempts aimed at providing an innovative contribution, an exchange between philosophy, epistemology and psychology about the place and value of reflection in everyday life.
Our goal in the next sections is not to offer an exhaustive overview of recent work on epistemic reflection, nor to mimic all of the contributions made by the chapters in this volume. We will try to highlight some topics that have motivated a new resumption of this field and, with that, drawing on chapters from this volume where relevant.
Two elements defined the scope and content of this volume, on the one hand, the crucial contribution of Ernest Sosa, whose works provide original and thought-provoking contributions to contemporary epistemology in setting a new direction for old dilemmas about the nature and value of knowledge, giving a central place to reflection. On the other hand, the recent developments of cultural psychology, in the version of the “Aalborg approach”, reconsider the object and scope of psychological sciences, stressing that “[h]uman conduct is purposeful”
Quantum state tomography by continuous measurement and compressed sensing
The need to perform quantum state tomography on ever larger systems has
spurred a search for methods that yield good estimates from incomplete data. We
study the performance of compressed sensing (CS) and least squares (LS)
estimators in a fast protocol based on continuous measurement on an ensemble of
cesium atomic spins. Both efficiently reconstruct nearly pure states in the
16-dimensional ground manifold, reaching average fidelities FCS = 0.92 and FLS
= 0.88 using similar amounts of incomplete data. Surprisingly, the main
advantage of CS in our protocol is an increased robustness to experimental
imperfections
Enhanced activity of anticarsia gemmatalis hüb. (lepidoptera: noctuidae) nuclear polyhedrosis virus by boric acid in the laboratory.
ABSTRACT Boric acid concentrations (0.02,0.03,0.045,0.067 and 0.101 g/100 ml of diet) were evaluated in combination with the Anticarsia gemmatalis Hüb. nuclear polyhedrosis virus (AgNPV) for enhanced virali activity against the insect. Seven days after inoculation, the median lethal concentration (LC50) was 1.52 x 105 for the AgNPV alone and 7.95 x 102 for the NPV mixed with 0.045g of boric acid/100 ml of diet. At subsequent evaluation dates (9,11 and 14 days after inoculation) LC50's for NPV+boric acid were ca. 4x lower than those observed for the NPV alone. The median lethal time (LT50) was 13.6 days when the NPV was used alone, while, when in mixture with increasing concentrations of boric acid, LT50 values ranged from 13.7 days (boric acid at 0.02g/100 ml of diet) to 7.4 days (boric acid at 0.101 g/ml of diet). Therefore, boric acid added to the AgNPV significantly increased A. gemmatalis larval mortality and shortened mortality time by the pathogen. Key words: Insecta, velvetbean caterpiliar, biological control, baculovirus
In vitro regeneration of Calophyllum brasiliense Cambess: A valuable medicinal tree
Calophyllum brasiliense (Calophyllaceae) is a medicinal tree known mainly for producing calanolides, secondary metabolites against HIV-1 reverse transcriptase. This wild plant is listed as threatened and despite its outstanding medicinal value, no studies have been conducted on its propagation or preservation. This study standardized a procedure for the micropropagation of C. brasiliense with nodal segments from in vitro seedlings. The in vitro seed germination was 48.6%. The nodal explants displayed a high percentage of shoot induction (77.5%), shoots per segment (6.9), nodes per shoot (3.8), leaves per shoot (8.0) and shoot length (4.2 cm) when 0.5 mg L-1 indole-3-butyric acid plus 0.1 mg L-1 thidiazuron were used. Furthermore, maximum shoot rooting (63.5%) and root length (2.2 cm) were recovered using 1.0 mg L-1 indole-3-acetic acid. More than three-quarters of the acclimatized plants (77.5%) grew successfully in pots. Thus, this study developed an in vitro propagation protocol for C. brasiliense that can be used as a potential resource for restoring wild populations or performing phytopharmacological studies.Key words: Seed germination, plant growth regulators, micropropagation, nodal segments, medicinal plants
Seleção de isolados de vírus e determinação da concentração letal média (CL50) para controle de S. Eridania, S. Cosmioides e S. frugiperda.
Os lepidópteros desfolhadores principalmente do gênero Spodoptera são atualmente um dos mais importantes problemas entomológicos em várias culturas de expressão econômica. Como alternativa ao controle químico, podem ser utilizados microrganismos entomopatogênicos, incluindo bactérias, vírus, fungos e protozoários. Este trabalho teve como objetivo avaliar isolados de vírus para as espécies de S. cosmioides, S. eridania e S. frugiperda. Lagartas de 3º instar (n=50), foram inoculadas com uma suspensão viral [1,0 x 107 corpos poliédricos de inclusão do vírus (CPI/mL)] incorporada na dieta artificial a fim de analisar a mortalidade causada por diferentes isolados de vírus. Para a determinação da CL50 seguiu-se a mesma metodologia, porém utilizando 80 lagartas por concentração (concentrações de 4.000; 8.000; 16.000; 32.000; 64.000 e 128.000 CPI/mL). Os dados de mortalidade foram submetidos à análise Probit, para a estimação CL50, bem como dos parâmetros associados (Intervalo de confiança (IC 95%) e ?2). Para a espécie S. cosmioides o isolado VPN 72 isolado desta mesma espécie resultou em mortalidade de 20%. Os isolados VNP 143, 144 e 152 obtidos de outros hospedeiros, mataram 24, 100 e 80% respectivamente. As lagartas de S. frugiperda apresentaram mortalidade de 100% somente com os isolados obtidos da mesma espécie VPN 76 e VG 89. S. eridania teve 20% de mortalidade com o isolado VPN 144, sendo este isolado o único que provocou mortalidade nas duas espécies. Os valores de ?2 calculados não foram significativos, indicando a homogeneidade dos dados e, principalmente, que os dados adaptaram-se ao modelo de análise Probit. O VPN 144 de A. californica inoculado em S. albula, testado em S. cosmioides apresentou a menor CL50, caracterizando-se como o mais virulento, quando comparado ao VPN 152 que resultou em CL50 de 49,13 CPI/mL ou seja foi duas vezes menos virulento que o VPN 144. Esse mesmo isolado testado em S. eridania foi 67 vezes menos virulento quando comparado com a espécie de S. cosmioides. Esta espécie apresentou-se a mais suscetível a isolados de vírus provenientes de outros hospedeiros.SICONBIOL 2011
N-ftaloil-glicin-hidroksamska kiselina kao kelator željeza u serumu štakora
The aim of this study was to investigate the activity of N-phthaloyl-glycine-hydroxamic acid (Phth-Gly-HA) as a new iron chelator in vivo to be used in iron overload diseases. After intraperitoneal application of Phth-Gly-HA to male rats (1 mg kg1 body mass) once a day for seven days, iron serum level decreased by 21%, whereas the iron value dropped by 32% in female rats (1.5 mg kg1 body mass). The results indicate that the tested substance has the ability to bind serum iron by complexation. Besides transferrin iron release, mobilization of ferritin iron is also possibleU cilju pronalaženja novog efikasnog kelatora koji bi mogao poslužiti u liječenju bolesti izazvanih viškom željeza, u ovom je radu ispitano djelovanje N-ftaloil-glicin-hidroksamske kiseline (Phth-Gly-HA) in vivo. Istraživan je utjecaj kelatora na razinu željeza u serumu štakora nakon intraperitonealne primjene vodene otopine Phth-Gly-HA (0,1 mg mL1) jednom dnevno tijekom 7 dana. Kontrolne su životinje primale fiziološku otopinu. Kod mužjaka injektiranje test supstancije (1 mg kg1) uzrokovalo je pad serumskog željeza za 21%. Kod ženki je nakon tretmana (1,5 mg kg1) izmjereno sniženje razine željeza za 35%. Rezultati pokazuju da ispitivana supstanca ima sposobnost kompleksiranja serumskog željeza, pretežno transferinskog, ali da postoji mogućnost mobilizacije željeza i iz feritinskih zaliha
Trypanosomatid prevalence in Nezara viridula (L.), Euschistus heros (Fabricius) and Piezodorus guildinii (Westwood) (Heteroptera: Pentatomidae) populations in Northern Paraná, Brazil.
The stink bug complex in soybeans has a great potential to cause damage, their control has been difficult due to high population densities at the end of the season. Studies related to entomopathogenic organisms in stink bugs are interesting for their possibilities to be used as biological control agents and because they could be an etiological agent in mass rearing. We determined the prevalence of trypanosomatids in the most important species of the stink bugs complex in soybean, from Brazil, Nezara viridula (L.) Euschistus heros (Fabricius) and Piezodorus guildinii (Westwood). Insects were collected in soybean and on alternate hosts during the intercrop season. Hemolymph drops fromeach adult were mounted on slides and observed under microscope: stink bug numbers with and without flagellates were recorded. The flagellates found in P. guildinii or E. heros populations were smaller than that found in N. viridula. The higher prevalence of the trypanosomatids was observed on soybean reaching a peak of 30% of the sampled N. viridula specimens in January, 2001, and 44% prevalence in February, 2003. The maximum prevalences (16%) in P. guildinii were observed in January and February, 2003 and on July 27, 2003 with 20% of the specimens infected. Flagellates in the hemolymph of E. heros were less frequent (maximum prevalence of 8.7%), suggesting that this species is less susceptible than N. viridula and P. guildinii. Trypanosomatid prevalence was higher than that observed for entomopathogenic fungi, however they seem to be inefficient control agents in short term condition
Feasibility, drug safety, and effectiveness of etiological treatment programs for Chagas disease in Honduras, Guatemala, and Bolivia: 10-year experience of Médecins Sans Frontières
BACKGROUND: Chagas disease (American trypanosomiasis) is a zoonotic or anthropozoonotic disease caused by the parasite Trypanosoma cruzi. Predominantly affecting populations in poor areas of Latin America, medical care for this neglected disease is often lacking. Médecins Sans Frontières/Doctors Without Borders (MSF) has provided diagnostic and treatment services for Chagas disease since 1999. This report describes 10 years of field experience in four MSF programs in Honduras, Guatemala, and Bolivia, focusing on feasibility protocols, safety of drug therapy, and treatment effectiveness. METHODOLOGY: From 1999 to 2008, MSF provided free diagnosis, etiological treatment, and follow-up care for patients <18 years of age seropositive for T. cruzi in Yoro, Honduras (1999-2002); Olopa, Guatemala (2003-2006); Entre Ríos, Bolivia (2002-2006); and Sucre, Bolivia (2005-2008). Essential program components guaranteeing feasibility of implementation were information, education, and communication (IEC) at the community and family level; vector control; health staff training; screening and diagnosis; treatment and compliance, including family-based strategies for early detection of adverse events; and logistics. Chagas disease diagnosis was confirmed by testing blood samples using two different diagnostic tests. T. cruzi-positive patients were treated with benznidazole as first-line treatment, with appropriate counseling, consent, and active participation from parents or guardians for daily administration of the drug, early detection of adverse events, and treatment withdrawal, when necessary. Weekly follow-up was conducted, with adverse events recorded to assess drug safety. Evaluations of serological conversion were carried out to measure treatment effectiveness. Vector control, entomological surveillance, and health education activities were carried out in all projects with close interaction with national and regional programs. RESULTS: Total numbers of children and adolescents tested for T. cruzi in Yoro, Olopa, Entre Ríos, and Sucre were 24,471, 8,927, 7,613, and 19,400, respectively. Of these, 232 (0.9%), 124 (1.4%), 1,475 (19.4%), and 1,145 (5.9%) patients, respectively, were diagnosed as seropositive. Patients were treated with benznidazole, and early findings of seroconversion varied widely between the Central and South American programs: 87.1% and 58.1% at 18 months post-treatment in Yoro and Olopa, respectively; 5.4% by up to 60 months in Entre Ríos; and 0% at an average of 18 months in Sucre. Benznidazole-related adverse events were observed in 50.2% and 50.8% of all patients treated in Yoro and Olopa, respectively, and 25.6% and 37.9% of patients in Entre Ríos and Sucre, respectively. Most adverse events were mild and manageable. No deaths occurred in the treatment population. CONCLUSIONS: These results demonstrate the feasibility of implementing Chagas disease diagnosis and treatment programs in resource-limited settings, including remote rural areas, while addressing the limitations associated with drug-related adverse events. The variability in apparent treatment effectiveness may reflect differences in patient and parasite populations, and illustrates the limitations of current treatments and measures of efficacy. New treatments with improved safety profiles, pediatric formulations of existing and new drugs, and a faster, reliable test of cure are all urgently needed
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