285 research outputs found

    Candida antarctica lipase-catalyzed synthesis and characterization of novel acrylic teroligomers

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    The synthesis of three novel low molecular weight acrylic terpolymers, containing at random sequences of ethyl acrylate, acrylic acid and N-(2-hydroxyethyl)acrylamide, catalyzed by Candida antarctica lipase was successfully conducted in organic media. For the first time, these products have been enzymatically synthesized using ethyl acrylate as the only monomer starting material and taking advantage of a triple activity displayed by the lipase. In the presence of ethanolamine, the enzyme not only catalyzes the chain polymerization of ethyl acrylate but also the aminolysis and hydrolysis of the pendant ester groups affording the terpolymers. The products were characterized by 1H and 13C NMR and UV-MALDI-TOF-MS.Fil: Baldessari, Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; ArgentinaFil: Fatema, M. Kaniz. Ehime University; JapónFil: Nonami, Hiroshi. Ehime University; JapónFil: Erra Balsells, Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Rustoy, Eduardo Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentin

    Side-effects of a number of insecticides on predatory mites in apple orchards

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    Background: Amblyseius andersoni is a common predatory mite occurring in fruit orchards located in Europe and North America. Its role in preventing spider mite outbreaks is widely recognized, in particular when selective pesticides are used. The compatibility between plant protection products and predatory mites is crucial to preserve their activity. There is a need to investigate the effects of pesticides on beneficials using multiple approaches. Objectives: Field and laboratory experiments were conducted to evaluate the effects of a number of insecticides on A. andersoni. Methods: The effects of neonicotinoids (i.e., acetamiprid, imidacloprid, thiacloprid, thia-methoxam) were compared with those of pyrethroids (i.e., tau-fluvalinate), well known for their negative impact on predatory mites. Insecticides were applied 1-3 times in an experimental fruit orchard located in Northern Italy. Laboratory trials focused on their effects on the survival and the fecundity of predatory mite females. Results: Field experiments showed a decline in predatory mite numbers in plots treated with neonicotinoids or tau-fluvalinate compared to the untreated control. However, predatory mites in neonicotinoid plots reached higher densities compared to those recorded in tau-fluvalinate plots. Spider mite (Panonychus ulmi) populations reached moderate to high densities in plots treated with tau-fluvalinate while their densities were negligible in the remaining plots. Amblyseius andersoni survival was moderately affected by some neonicotinoids in the laboratory while they significantly reduced predatory mite fecundity. In contrast tau-fluvalinate exerted severe effects on survival and fecundity of predatory mites. Finally, escaping rate increased after pesticide exposure suggesting possible alterations in predatory mite behavior. Conclusions: Neonicotinoid applications significantly affected predatory mite densities in field conditions and this phenomenon appeared to be influenced by their impact on female fecundity. Their effects on survival were less severe. Implications of these results for IPM tactics in fruit orchards are discusse

    Is Eriophyes mali Nalepa present in Italy?

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    In the last few years, blistering symptoms were observed on apple plants in commercial orchards. Blisters are commonly found on apple leaves as well as on small fruits. This symptom is compatible with that described for apple blister mites belonging to the genus Eriophyes (Eriophyidae). To assess the identity of the etiological agent, leaf blisters and buds of symptomatic apple and, as a control, pear plants were examined under the dissection microscope and eriophyoid mites were collected. Specimens were examined using both molecular and morphological approaches. The analysis of sequences confirmed that eriophyoid mites collected from symptomatic apple and pear plants are genetically different. Our analyses highlight a complex scenario inside the genus Eriophyes that is worth to be studied in more detai

    Successes and failures of angiogenesis blockade in gastric and gastro-esophageal junction adenocarcinoma

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    Gastric and gastro-esophageal junction adenocarcinoma (GEA) remains a considerable major public health problem worldwide, being the fifth most common cancer with a fatality-to-case ratio that stands still at 70%. Angiogenesis, which is a well-established cancer hallmark, exerts a fundamental role in cancer initiation and progression and its targeting has been actively pursued as a promising therapeutic strategy in GEA. A wealth of clinical trials has been conducted, investigating anti-angiogenic agents including VEGF-directed monoclonal antibodies, small molecules tyrosine kinase inhibitors and VEGF-Trap agents both in the resectable and advanced setting, reporting controversial results. While phase III randomized trials testing the anti-VEGFR-2 antibody Ramucirumab and the selective VEGFR-2 tyrosine kinase inhibitor Apatinib demonstrated a significant survival benefit in later lines, the shift of angiogenesis inhibitors in the perioperative and first-line setting failed to improve patients’ outcome in GEAs. The molecular landscape of disease, together with novel combinatorial strategies and biomarker-selected approaches are under investigation as key elements to the success of angiogenesis blockade in GEA. In this article, we critically review the existing literature on the biological rationale and clinical development of antiangiogenic agents in GEA, discussing major achievements, limitations and future developments, aiming at fully realizing the potential of this therapeutic approach

    Effects of Aculus schlechtendali (Acari: Eriophyidae) population densities on Golden Delicious apple production

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    Field trials were carried out in order to evaluate the seasonal abundance and the impact on yields of the Apple Rust Mite (ARM) Aculus schlechtendali (Acari: Eriophyidae) in an experimental fruit orchard located in northern Italy (Trentino region). The effect of ARM on yield and market quality parameters were assessed on Golden Delicious apple fruits. Fruit size, fruit weight, round colour hue, presence of russet as well as inside quality, i.e. soluble solids, acidity and Perlim index, were evaluated over two seasons considering three population levels of ARM that were determined applying different pesticide strategies. Effects of rust mites on return bloom and yield efficiency were also evaluated. ARM seasonal abundance showed a peak in mid-summer. Relationships between ARM and predatory mites were weak. Moderate to high ARM densities affected fruits size, fruit weight, and round colour hue of Golden Delicious fruits. In contrast, ARM populations did not affect russet on fruits, return bloom and yield efficiency. Additional studies were conducted in the laboratory, on detached Golden Delicious apple leaves, to evaluate the potential for population increase at temperatures close to those recorded in field conditions. These studies evidenced a high potential for population increase
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