204 research outputs found

    Selection of Beauveria bassiana sensu lato and Metarhizium anisopliae sensu lato isolates as microbial control agents against the boll weevil (Anthonomus grandis) in Argentina

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    The boll weevil (Anthonomus grandis) is the main pest of cotton in the Americas. The aim of this work was to evaluate isolates of the entomopathogenic fungi Beauveria bassiana sensu lato and Metarhizium anisopliae sensu lato virulent against A. grandis. Screening was performed to evaluate the pathogenicity of 28 isolates of M. anisopliae s.l. and 66 isolates of B. bassiana s.l. against boll weevil adults. To select the isolates, LC 50 values of the most virulent isolates were calculated, and compatibility between the fungi and insecticides was studied. In addition, the effects of these isolates on the feeding behavior of the adults were evaluated. Isolates Ma 50 and Ma 20 were the most virulent against A. grandis and their LC 50 values were 1.13×10 7 and 1.20×10 7 conidia/ml, respectively. In addition, these isolates were compatible with pyrethroid insecticides, but none with endosulfan. On the other hand, infected females reduced the damage caused by feeding on the cotton squares and their weight gain. This shows that entomopathogenic fungi cause mortality in the insects, but also these fungi could influence the feeding behavior of the females. In summary, these results indicate the possibility of the use of M. anisopliae s.l. as a microbiological control agent against boll weevils. Also, this species could be included in an Integrated Pest Management program.Fil: Nussenbaum, Ana Laura. Instituto Nacional de TecnologĂ­a Agropecuaria. Centro de InvestigaciĂłn en Ciencias Veterinarias y AgronĂłmicas. Instituto de MicrobiologĂ­a y ZoologĂ­a AgrĂ­cola; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: Lecuona, R. E.. Instituto Nacional de TecnologĂ­a Agropecuaria. Centro de InvestigaciĂłn en Ciencias Veterinarias y AgronĂłmicas. Instituto de MicrobiologĂ­a y ZoologĂ­a AgrĂ­cola; Argentin

    Sensory integration intervention and the development of the premature infant: A controlled trial

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    Background. Premature infants are at risk of sensory processing difficulties and developmental delays due to an immature central nervous system and possible episodes of medical instability, discomfort, pain and stress during the first weeks or months after birth.Objective. To investigate the effect of Ayres Sensory Integration (ASI) on the development of premature infants in the first 12 months of life.Methods. A pre-/post-test experimental design was used to randomly divide 24 premature infants from a low socioeconomic setting in Bloemfontein, South Africa, into experimental and control groups after being matched by corrected age and gender. Developmental status was determined with the Bayley III Scales of Infant and Toddler Development, the Test of Sensory Functions in Infants and the Infant/ Toddler Sensory Profile. The experimental group received 10 weeks of ASI intervention.Results. ASI intervention had a positive effect on the sensory processing and development of premature infants, especially in terms of cognitive, language and motor development.Conclusions. ASI intervention at an early age enhances the developmental progress of premature infants

    Transcranial magnetic stimulation in depression--lessons from the multicentre trials

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    Looking at novelties and advances in medicine in particular in the treatment of major depressive disorder no principally new antidepressant treatment strategy has been established in clinical routine in the last fifty years. However, regarding the considerable issue of treatment resistance in depression, new therapeutic strategies are urgently required. In this context, repetitive transcranial magnetic stimulation above the dorsolateral prefrontal cortex has been proposed as a potential new treatment option for depression; furthermore, in October 2008 a first rTMS-device (NeuroStar TMS Therapy Systemℱ) was approved by the FDA for the treatment of treatment resistant major refractory depression in adults. Yet, despite now nearly two decades of research in this field, no final answer concerning its validity for antidepressant treatment in the clinical practice is given. Numerous studies with small sample sizes and heterogeneous designs have been performed in this field yielding to different results. These were subjected to meta-analyses, assessing the antidepressant effect of rTMS, which are briefly summarized in this article. Further, multicentre-trials with larger numbers of patients were performed, which are presented and critically discussed here in more detail. This short review shall thus provide an overview of the current status of knowledge concerning rTMS in depression and it also provides some recommendations for future research in this field

    Effect of Constant and Cyclical Temperatures on the Mortality of Triatoma infestans (Klug) (Hemiptera: Reduviidae) Treated with Beauvaria bassiana (Bals.) Vuill. (Hyphomycetes)

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    Neotropical Entomology 34(4): Efecto de Temperaturas Constantes y CĂ­clicas sobre la Mortalidad de Triatoma infestans (Klug) (Hemiptera: Reduviidae) Tratada con Beauveria bassiana (Bals.) Vuill. PALABRAS CLAVE: RegĂ­men fluctuante, germinaciĂłn, hongo entomopatĂłgeno ABSTRACT -The mortality of Triatoma infestans (Klug) treated with Beauvaria bassiana (Bals.) Vuill. under several temperature regimes was analyzed. Mortality rates were highest at 26ÂșC and 22ÂșC and lowest at constant 34ÂșC. The combinations 26/34ÂșC or 34/26ÂșC (12:12h cycles) were significantly different from the combinations 18/26ÂșC and 26/18ÂșC, showing that high temperatures (34ÂșC) affect mortality most significantly. The combinations also indicate that when an extreme high temperature is associated with an optimal temperature of 26ÂșC, the susceptibility of T. infestans to B. bassiana infection decreases. Exposure to extreme temperature (18ÂșC or 34ÂșC) associated with an optimal temperature of 26ÂșC in 8:8:8h cycles, reduces the mortality of T. infestans. In cycles of 6:6:6:6h, only the mortality associated with the 34/30/26/22ÂșC combination was similar to the combinations at constant 22ÂșC and 26ÂșC. Extreme temperatures during the first stage affect mortality less than when this period is not longer than 6h. Mortality decreases significantly when an extreme high initial temperature is followed by an abrupt fall (34/22/26/30ÂșC). Our results indicate that Beauvaria bassiana should be applied to the field in the late afternoon to avoid the negative impact of abrupt changes in temperature, or of high temperatures during the critical first stages of the infectious cycle of this entomopathogenic fungi. KEY WORDS: Fluctuating regime, germination, entomapathogenic fungus The blood-sucking bug Triatoma infestans (Klug) (Hemiptera: Reduviidae), the most important vector of Chagas disease, is well adapted to domestic and peridomestic habitats (Rabinovich 1972).The entomopathogenic fungus Beauvaria bassiana (Bals.) Vuill. (Hyphomycetes) controlled T. infestans under laboratory conditions (Lecuona et al. 2000). 676 Effect of Constant and Cyclical Temperatures on the Mortality of Triatoma... Lecuona et al. In insects, development of Hyphomycetes mycosis occurs in 10 stages The disease cycle is influenced by several factors, including environmental conditions such as temperature, relative humidity, and light (Alves 1998). Temperature is one of the most important factors because it affects both the growth of B. bassiana Material and Methods Populations of T. infestans. Specimens of T. infestans were collected in rural areas of Santiago del Estero by employees of the Servicio Nacional de Chagas (Cordoba, Argentina). The insects were reared in the laboratory at 27 ± 1ÂșC and 80 ± 10% relative humidity (R.H.), and fed on chickens. Thirdinstar nymphs (N3) that belonged to this colony were taken to the Laboratory of Entomopathogenic Fungi (Laboratorio de Hongos EntomopatĂłgenos -IMYZA-INTA Castelar, Buenos Aires), where the experiments were conducted. Cultivation of B. bassiana. A strain Bb10 that belongs to the fungal culture collection of the IMYZA-INTA Castelar was used. The strain was isolated from Diatraea saccharalis (Fabricius) (Lepidoptera: Pyralidae), in Argentina. Before the strain could be used in this study, it was isolated a second time in nymphs of T. infestans. The strain was maintained in a petri dish with complete agar medium (CAM) containing (g/l): KH 2 PO 4 , 0.4; Na 2 HPO 4 , 1.4; MgSO 4 , 0.6; KCl, 1; NH 4 NO 3 , 0.7; glucose, 10; agar, 15; and yeast extract, 5. Conidia were extracted from 14-days old fungal colonies, and were incubated in petri dishes at 26 ± 0.5ÂșC. Viability was assessed at 18, 22, 26, 30 and 34 ± 0.5ÂșC by counting the number of conidia that had germinated. The conidia were incubated in CAM with 1 x 10 7 conidia/ml, in 10 microscopic fields 8, 12, 16, 20 and 24h after planting. Conidia are considered germinated when the germination tubule reaches a length that is the same, or greater than the widest part of the conidial body. Mortality of T. infestans under Constant and Fluctuating Temperature Regimes. The activity of the strain Bb10 on T. infestans was analyzed by means of a completely random design with 20 N3 nymphs in each repetition. The number of repetitions varied from six to 24, depending on the availability of insects. Nymphs were fed on chickens up to a week before the assays started. Inoculation was carried out by immersion, 6 min after each repetition, in a suspension of 1 x 10 8 conidia/ml in sterile water with 0.01% Tween 80. The insects were placed in a plastic cylindrical sieve (4 x 4.5 cm) for immersion. After immersion in the fungal suspension, each nymph was kept in a separate plastic container (4.5 x 2.5 cm), had their upper bodies covered with a voile fine cloth, and were maintained at different temperatures and in the dark, according to each treatment. The nymphs were not fed for 14 days. Control insects were dipped into sterile water with 0.01% Tween 80, also for six seconds. The assays were carried out at constant temperatures (18, 22, 26, 30 and 34 ± 0.5 o C), and daily temperature fluctuation cycles (12:12h, 8:8:8h and 6:6:6:6h). All the assays were conducted in the dark, at 80 ± 10% R.H. Nymph mortality was recorded daily, and cadavers were taken to a humid chamber (saturated atmosphere) for fungal sporulation. Mortality was analyzed by ANOVA and SNK, soon after the data arc sine transformation. Percentiles of the survival function were estimated by the Kaplan-Meier method Results and Discussion Mortality of T. infestans under Constant and Fluctuating Temperatures. Mortality percentage was higher at 26ÂșC in the 12:12h and 8:8:8h cycles, and at 26ÂșC and 22ÂșC in the 6:6:6:6h cycl

    Sensory integration intervention and the development of the premature infant: A controlled trial

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    Background. Premature infants are at risk of sensory processing difficulties and developmental delays due to an immature central nervous system and possible episodes of medical instability, discomfort, pain and stress during the first weeks or months after birth.Objective. To investigate the effect of Ayres Sensory Integration (ASI) on the development of premature infants in the first 12 months of life.Methods. A pre-/post-test experimental design was used to randomly divide 24 premature infants from a low socioeconomic setting in Bloemfontein, South Africa, into experimental and control groups after being matched by corrected age and gender. Developmental status was determined with the Bayley III Scales of Infant and Toddler Development, the Test of Sensory Functions in Infants and the Infant/Toddler Sensory Profile. The experimental group received 10 weeks of ASI intervention.Results. ASI intervention had a positive effect on the sensory processing and development of premature infants, especially in terms of cognitive, language and motor development.Conclusions. ASI intervention at an early age enhances the developmental progress of premature infants.

    Development of Alfalfa (Medicago Sativa L.) Transgenic Plants Expressing a Bacillus Thuringiensis Endotoxin and Their Evaluation Against Alfalfa Caterpillar (Colias Lesbia)

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    Alfalfa (Medicago sativa L.) is the most important forage crop in Argentina, with ca. 6 million cultivated hectares. The production of this crop is limited by the alfalfa caterpillar (Colias lesbia) which causes a loss equivalent to at least 10% of the biomass per year. No natural tolerance against this lepidoptera was found in alfalfa germplasm, hampering the development of tolerant cultivars by conventional breeding. This pest is usually controlled by using chemical insecticides but this has adverse effects on beneficial insects and the environment. Alternatively, low doses of commercial Bt insecticides (40 to 70 g/ha) also proved to efficiently limit the pest. This observation leads to us consider that the development of alfalfa transgenic plants expressing a suitable member of the B. thuringiensis cry gene family could be a useful tool for overcoming this alfalfa yield constraint. The aim of this work was to produce alfalfa transgenic plants expressing a Bt protein and to assess its biological activity against C. lesbia under laboratory conditions

    CD11b suppresses TLR activation of nonclassical monocytes to reduce primary graft dysfunction after lung transplantation

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    Primary graft dysfunction (PGD) is the leading cause of postoperative mortality in lung transplant recipients and the most important risk factor for development of chronic lung allograft dysfunction. The mechanistic basis for the variability in the incidence and severity of PGD between lung transplant recipients is not known. Using a murine orthotopic vascularized lung transplant model, we found that redundant activation of Toll-like receptors 2 and 4 (TLR2 and -4) on nonclassical monocytes activates MyD88, inducing the release of the neutrophil attractant chemokine CXCL2. Deletion of Itgam (encodes CD11b) in nonclassical monocytes enhanced their production of CXCL2 and worsened PGD, while a CD11b agonist, leukadherin-1, administered only to the donor lung prior to lung transplantation, abrogated CXCL2 production and PGD. The damage-associated molecular pattern molecule HMGB1 was increased in peripheral blood samples from patients undergoing lung transplantation after reperfusion and induced CXCL2 production in nonclassical monocytes via TLR4/MyD88. An inhibitor of HMGB1 administered to the donor and recipient prior to lung transplantation attenuated PGD. Our findings suggest that CD11b acts as a molecular brake to prevent neutrophil recruitment by nonclassical monocytes following lung transplantation, revealing an attractive therapeutic target in the donor lung to prevent PGD in lung transplant recipients
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