194 research outputs found

    Diachasmimorpha longicaudata (Hymenoptera: Braconidae) tem um Ă­nstar preferencial para parasitar Tephritidae (Diptera)?

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    Diachasmimorpha longicaudata (Ashmead, 1905) is a koinobiont parasitoid of Tephritidae larvae, the third instar larvae of which is considered preferential, but it is able to parasitize other larval stages and compete with native parasitoids. This study investigated the preference and parasitism capacity of D. longicaudata in larvae of different instar of Anastrepha fraterculus (Wiedemann, 1830) (AF) and Ceratitis capitata (Wiedemann, 1824) (CC). The experiments were carried out under laboratory conditions, one instar being offered at a time in parasitism units, with the following choices among the hosts: 25 AF larvae and 25 CC larvae (first, second and third instar were evaluated). The other test was a multiple-choice in relation to the instar, for larvae of the same host species, with three parasitism units being offered, with 15 larvae of each instar. The mean number of formed pupae, emerged parasitoids, parasitized pupae, unviable pupae and sex ratio were evaluated. In the first bioassay, the mean number of emerged parasitoids and parasitized pupae in the AF host were significantly higher in treatments with first and second instar larvae. For CC there was no difference between the instars tested. In the second bioassay, the mean value of emerged parasitoids and parasitized pupae, was higher in second and third instar larvae for CC, and for AF was in second instar larvae. The sex ratio was biased for males in all treatments in both bioassays. The results show that D. longicaudata can parasitize and be successful in all available larval instars, being able to compete with parasitoids of any instar.Diachasmimorpha longicaudata (Hymenoptera: Braconidae) tem um ínstar preferencial para parasitar Tephritidae (Diptera)? Diachasmimorpha longicaudata (Ashmead, 1905) é um parasitoide coinobionte de larvas de Tephritidae sendo que o terceiro ínstar larval é tido como o preferencial, mas pode parasitar outros estágios larvais e competir com os parasitoides nativos. Este estudo investigou a preferência e capacidade de parasitismo de D. longicaudata em larvas de diferentes ínstares de Anastrepha fraterculus (Wiedemann, 1830) (AF) e Ceratitis capitata (Wiedemann, 1824) (CC). Os experimentos foram realizados em condições laboratoriais, sendo oferecido um ínstar por vez em unidades de parasitismo, havendo escolha entre os hospedeiros: 25 larvas de AF e 25 larvas de CC (foram avaliadas larvas de primeiro, segundo e terceiro ínstar). O outro teste foi de múltipla escolha em relação ao ínstar, para larvas da mesma espécie hospedeira, sendo oferecidas três unidades de parasitismo, com 15 larvas de cada ínstar. Avaliou-se o número médio de pupários formados, parasitoides emergidos, pupários parasitados, pupas inviáveis e razão sexual. No primeiro bioensaio o número médio de parasitoides emergidos e pupários parasitados no hospedeiro AF foram significativamente superiores nos tratamentos com larvas de primeiro e segundo ínstar. Para CC não houve diferença entre os ínstares testados. No segundo bioensaio, o valor médio de parasitoides emergidos e de pupas parasitadas foi maior nas larvas de segundo e terceiro ínstar para CC, e para AF nas larvas de segundo ínstar. A razão sexual foi desviada para machos em todos os tratamentos, nos dois bioensaios. Os resultados demostram que D. longicaudata pode parasitar e ter sucesso em qualquer ínstar larval disponível, podendo competir com parasitoides de qualquer ínstar

    Intra and interspecific competition between Diachasmimorpha longicaudata (Hymenoptera Braconidae) and Aganaspis pelleranoi (Hymenoptera Figitidae)

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    Braconidae and Figitidae parasitoids are important agents of pest population regulation in natural and agricultural systems, with species used in applicate biological control programs of fruit flies (Diptera Tephritidae). However, many aspects of the interactions of parasitoids with their heterospecific and conspecific are poorly understood. Thus, the interspecific competition between the par- asitoids Diachasmimorpha longicaudata (Ashmead) (DL) (Hymenoptera Braconidae) and Aganaspis pelleranoi (Brethes) (AP) (Hymenoptera Figitidae), was studied using Anastrepha fraterculus (Wiedemann) (Diptera Tephritidae) as host. Host larvae were offered to only one parasitoid on a single occasion or on two occasions, or even to two parasitoid species, alternating the offering sequence. Thus, six exposure regimes were completed: AP (host exposed for 4 hours); DL (host exposed for 40 minutes); AP-AP (host exposed to AP for 4 hours and then to a conspecific for an additional further 4 hours); DL-DL (host exposed to DL for 40 minutes and then to a conspecific for an additional 40 minutes); AP-DL (host exposed to AP for 4 hours and then to DL for 40 minutes); and DL-AP (host exposed to DL for 40 minutes and then exposed to AP for 4 hours). The mean number of parasitized pupae, emerged parasitoids, oviposition scars per host (larvae) and sex ratio of parasitoids were compared between the different exposure regimes. The mean of parasitized pupae and emerged parasitoids was higher in the DL-DL and DL-AP treatments. The mean number of oviposition scars per host was correlated positively with the mean number of parasitoid offspring and the emerged females in treatments AP, DL, AP-AP, DL-DL for both species, and DL-AP only to D. longicaudata. When the hosts were exposed only once to the parasitoids, the sex ratio was male biased (AP and DL treatments); but when exposed twice, the treatments spawned offspring female biased, except for D. longicaudata at AP-DL treatment. Irrespective of the parasitism order, D. longicaudata suppress the emergence of A. pelleranoi

    Synthesis and nanoprecipitation of HEMA-CLnbased polymers for the production of biodegradable nanoparticles

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    The control over the size distribution and stability of polymeric nanoparticles (NPs) is crucial in many of their applications, especially in the biomedical field. These characteristics are typically influenced by the production method and the nature of the starting material. To investigate these aspects, the controlled radical polymerization of functionalized methacrylates constituted by 2-hydroxyethyl methacrylate (HEMA) functionalized with a controlled number of ε-caprolactone (CL) units (HEMA-CLn), was carried out via reversible addition–fragmentation chain transfer polymerization (RAFT) in solution. The living reaction allows for good control over the molar mass of the final polymer with a low molar mass dispersity. The obtained polymer solutions were nanoprecipitated in order to produce NPs suitable for drug delivery applications with narrow particle size distribution and a wide size range (from 60 to 250 nm). The NP synthesis has been performed using a mixing device, in order to control the parameters involved in the nanoprecipitation process. As already seen for similar systems, the size of the produced NPs is a function of the polymer concentration during the nanoprecipitation process. Nevertheless, when the polymer concentration is kept constant, the NP size is influenced by the chemical structure of the polymer used, in terms of the presence of PEG (poly(ethylene glycol)), the degree of RAFT polymerization, and the length of the caprolactone side chain. These characteristics were also found to influence the stability and degradation properties of the produced NPs

    Relationship between herpes simplex virus-1-specific antibody titers and cortical brain damage in Alzheimer's disease and amnestic mild cognitive impairment

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    This work was supported by 2012–2014 Ricerca Corrente (Italian Ministry of Health).Alzheimer's disease (AD) is a multifactorial disease with a still barely understood etiology. Herpes simplex virus 1 (HSV-1) has long been suspected to play a role in the pathogenesis of AD because of its neurotropism, high rate of infection in the general population, and life-long persistence in neuronal cells, particularly in the same brain regions that are usually altered in AD. The goal of this study was to evaluate HSV-1-specific humoral immune responses in patients with a diagnosis of either AD or amnestic mild cognitive impairment (aMCI), and to verify the possible relation between HSV-1-specific antibody (Ab) titers and cortical damage; results were compared to those obtained in a group of healthy controls (HC). HSV-1 serum IgG titers were measured in 225 subjects (83 AD, 68 aMCI, and 74 HC). HSV-specific Ab avidity and cortical gray matter volumes analyzed by magnetic resonance imaging (MRI) were evaluated as well in a subgroup of these individuals (44 AD, 23 aMCI, and 26 HC). Results showed that, whereas HSV-1 seroprevalence and IgG avidity were comparable in the three groups, increased Ab titers (p < 0.001) were detected in AD and aMCI compared to HC. Positive significant correlations were detected in AD patients alone between HSV-1 IgG titers and cortical volumes in orbitofrontal (region of interest, ROI1 RSp0.56; p = 0.0001) and bilateral temporal cortices (ROI2 RSp0.57; p < 0.0001; ROI3 RSp0.48; p = 0.001); no correlations could be detected between IgG avidity and MRI parameters. Results herein suggest that a strong HSV-1-specific humoral response could be protective toward AD-associated cortical damage.Publisher PDFPeer reviewe

    Sinopse internacional, n. 17, abr. 2012

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    Sinopse internacional, n. 16, out. 2011

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    Sinopse internacional

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