8,293 research outputs found

    Lysenko and the screwworm fly—when politics interferes with science and public health

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    In the One Health scenario, a deep understanding of the dynamics potentially threatening the development and implementation of useful pest and vector management tools is of key importance. The New World screwworm fly, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae), is characterized by a wide host range. It acts as an important agent of myiasis in humans and warm-blooded animals in the Neotropics, and has been eliminated from a wide region through genetic methods. Of note, Serebrovsky had already proposed in 1940 the principles of autocidal control by the translocation of segments between two chromosomes, but his work was negated by Lysenko, based on the negation of Mendelian genetics. This entomological case study emphasizes the danger of politics interfering with science, a still contemporary hot issue. The negation of global warming or current pandemics are further examples of this noxious influence

    Hyperspectral imaging to measure apricot attributes during storage

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    The fruit industry needs rapid and non-destructive techniques to evaluate the quality of the products in the field and during the post-harvest phase. The soluble solids content (SSC), in terms of °Brix, and the flesh firmness (FF) are typical parameters used to measure fruit quality and maturity state. Hyperspectral imaging (HSI) is a powerful technique that combines image analysis and infrared spectroscopy. This study aimed to evaluate the potential of the application of the Vis/NIR push-broom hyperspectral imaging (400 to 1000 nm) to predict the firmness and the °Brix in apricots (180 samples) during storage (11 days). Partial least squares (PLS) and artificial neural networks (ANN) were used to develop predictive models. For the PLS, R2 values (test set) up to 0.85 (RMSEP=1.64 N) and 0.72 (RMSEP=0.51 °Brix) were obtained for the FF and SSC, respectively. Concerning the ANN, the best results in the test set were achieved for the FF (R2=0.85, RMSEP=1.50 N). The study showed the potential of the HSI technique as a non-destructive tool for measuring apricot quality even along the whole supply chain

    Newer Approaches for Malaria Vector Control and Challenges of Outdoor Transmission

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    The effective and reliable management of malaria vectors is still a global challenge. Recently, it has been noted that the first vaccine against Plasmodium falciparum malaria, RTS,S/AS01 showed only transient protection, particularly in infants, and rapid resistance has been developing to artemisinin-based drugs. Therefore, the control of malaria mosquito vectors according to strategies of integrated vector management (IVM) is receiving emphasis. A rather wide number of novel mosquito control tools have been tested, including attractive toxic sugar baits, eave tubes, nano-synthesized pesticides loaded with microbial- and plant-borne compounds, biocontrol agents with little non-target effects, new adult repellents, oviposition deterrents, and even acoustic larvicides. However, their real-world applications remain limited. Most National Malaria Control Programs in Africa still rely on indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) to reduce malaria incidence but generally have insufficient impact on malaria prevalence. Here, we focus on facts, trends, and current challenges in the employment of the above-mentioned vector control tools in the fight against malaria. We emphasize the needs for better vector control tools used in IVM to overcome the challenges posed by outdoor transmission and growing levels of insecticide resistance, which are threatening the efficacy of LLINs and IRS

    Estratégias para reduzir a mortalidade embrionária em bovinos: II. Protocolo para reduzir a mortalidade embrionária em vacas de leite e em receptoras de embrião.

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    A mortalidade embrionária precoce é a maior causa de perdas reprodutivas em bovinos e ela relaciona-se, principalmente com os distúrbios do reconhecimento materno da prenhez originados em disfunções do corpo lúteo ovariano. Recentemente, foi desenvolvido na Embrapa Pecuária Sudeste, um protocolo hormonal que melhora a função luteínica e permite aumentar a oportunidade para um reconhecimento materno da prenhez bem sucedido. O protocolo baseia-se na administração de hormônios reprodutivos (GnRH e hCG) em ocasiões estratégicas após a ovulação. Foram realizados dois experimentos, um com vacas leiteiras e outro com receptoras de embrião, para testar e validar o uso desse protocolo. Após a aplicação do tratamento houve aumento nas taxas de prenhez. Os resultados detalhados do uso dessa prática estão descritos no presente Boletim de Pesquisa e Desenvolvimento. O protocolo testado traduz-se numa prática pecuária de controle das funções ovariana e uterina que otimiza a eficiência reprodutiva de vacas leiteiras e de receptoras de embrião.bitstream/item/43513/1/Boletim27.pd

    Oviposition inhibitory activity of the Mexican sunflower Tithonia diversifolia (Asteraceae) polar extracts against the two-spotted spider mite Tetranychus urticae (Tetranychidae)

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    The Mexican sunflower (Tithonia diversifolia, Asteraceae) is an invasive shrub of agricultural and non-agricultural lands in tropical countries. Besides extensive utilizations in the traditional medicine, mainly to treat malaria, the plant is believed to have a great potential in agriculture of developing countries as a green biomass to produce fertilizer, fodder and biopesticides. The plant is known to produce tagitinins, which are sesquiterpene lactones with a bitter taste endowed with toxicity against several insects such as mosquitoes, aphids, and beetles. Here, we evaluated the potential of T. diversifolia against the two-spotted spider mite Tetranychus urticae (Tetranychidae), which is one of the most economically important arthropod pests worldwide. The leaf methanolic extract and its ethyl acetate fraction were tested for acute and chronic toxicity and for oviposition inhibitory effects. The chemical composition of the extracts was analyzed by HPLC-MSn and NMR. The main constituents were flavonoid derivatives, phenylpropanoids and sesquiterpene lactones. Among the latter, tagitinin C and tagitinin A were the major compounds. In acute toxicity assays, mortality did not exceed 50% even for the highest tested dose of 150 \u3bcg cm-3. However, in chronic toxicity assays, on day 5 from application, the methanolic extract LD50 was 41.3 \u3bcg cm-3 while LD90 was 98.7 \u3bcg cm-3. Furthermore, both T. diversifolia extracts inhibited oviposition in T. urticae. The ethyl acetate extract was the most active oviposition inhibitor, with an ED50 value of 44.3 \u3bcg cm-3 and an ED90 of 121.5 \u3bcg cm-3. Overall, the good yield rate of the extract and the high crop yield highlighted good prospects of using the extract from this plant for the development of oviposition inhibitors against mite

    Beta-tricalcium phosphate ceramic triggers fast and robust bone formation by human mesenchymal stem cells

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    Due to their osteoconductive and inductive properties, a variety of calcium phosphate (CaP) scaffolds are commonly used in orthopaedics as graft material to heal bone defects. In this study, we have used two CaP scaffolds with different hydroxyapatite (HA) and \u3b2-tricalcium phosphate (\u3b2-TCP) ratios (MBCP\uae; 60/40 and MBCP+\uae; 20/80) to investigate their intrinsic capacity to favour human bone marrow stem cells (hBMSCs) osteogenic differentiation capacity. We report that MBCP+\uae showed in in vitro culture model a higher rate of calcium ion release in comparison with MBCP\uae. In two defined coculture systems, the hBMSC seeded onto MBCP+\uae presented an increased amount of VEGF secretion, resulting in an enhanced endothelial cell proliferation and capillary formation compared with hBMSC seeded onto MBCP\uae. When both ceramics combined with hBMSC were implanted in a nude mouse model, we observed a faster osteogenic differentiation and enhancement mature bone deposition sustained by the presence of a vast host vasculature within the MBCP+\uae ceramics. Bone formation was observed in samples highly positive to the activation of calcium sensing receptor protein (CaSr) on the surface of seeded hBMSC that also shown higher BMP-2 protein expression. With these data we provide valuable insights in the possible mechanisms of ossification and angiogenesis by hBMSC that we believe to be primed by calcium ions released from CaP scaffolds. Evidences could lead to an optimization of ceramic scaffolds to prime bone repair

    Impact of Different Developmental Instars on Locusta migratoria Jumping Performance

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    Ontogenetic locomotion research focuses on the evolution of locomotion behavior in different developmental stages of a species. Unlike vertebrates, ontogenetic locomotion in invertebrates is poorly investigated. Locusts represent an outstanding biological model to study this issue. They are hemimetabolous insects and have similar aspects and behaviors in different instars. This research is aimed at studying the jumping performance of Locusta migratoria over different developmental instars. Jumps of third instar, fourth instar, and adult L. migratoria were recorded through a high-speed camera. Data were analyzed to develop a simplified biomechanical model of the insect: the elastic joint of locust hind legs was simplified as a torsional spring located at the femur-tibiae joint as a semilunar process and based on an energetic approach involving both locomotion and geometrical data. A simplified mathematical model evaluated the performances of each tested jump. Results showed that longer hind leg length, higher elastic parameter, and longer takeoff time synergistically contribute to a greater velocity and energy storing/releasing in adult locusts, if compared to young instars; at the same time, they compensate possible decreases of the acceleration due to the mass increase. This finding also gives insights for advanced bioinspired jumping robot design

    Drying Techniques and Storage: Do They Affect the Nutritional Value of Bee-Collected Pollen?

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    In this study, the effect of different drying processes (freeze-drying (FD), microwave-assisted drying (MWD) and classic hot air drying (HAD)) on the polyphenols, flavonoids, and amino acids content was investigated on bee-collected chestnut, willow and ivy pollen for human consumption. Furthermore, the pollen chemical properties were monitored after three and six months of storage, and then analyzed using a multivariate approach. Chestnut pollen was the richest source of polyphenols, flavonoids, and rutin, while ivy pollen contained the highest amount of total and free amino acids, and total and free proline. Drying and storage affected pollen chemical composition with species-dependent effects. MWD allowed the best retention of flavonoids in chestnut pollen for up to six months of storage. All drying techniques led to a depletion of flavonoids in willow pollen; however, MWD ensured the highest flavonoids content after six months. FD and MWD did not lead to flavonoids depletion in ivy pollen during storage. Additionally, storage did not affect the rutin content, which was highest in FD willow samples after six months. Notably, both FD and MWD techniques are efficient in preserving amino acids-related quality of bee pollen up to six months of storage

    Large-scale plant production of lycium barbarum l. By liquid culture in temporary immersion system and possible application to the synthesis of bioactive substance

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    Goji (Lycium barbarum L.) has recognized nutritive and antioxidant properties and many products are commercialized for health in food market. Besides its food use, goji has been the subject of more than 2000 years of traditional Chinese medicine, using berries, root bark, and leaves. Here, the potential of the liquid culture in temporary immersion system (TIS) by using the bioreactor Plantformâ„¢ was tested for the large-scale production of high-quality goji shoots and the subsequent production of total phenols and flavonoids. The three tested immersion cycles differently influenced the shoot quality in terms of proliferation and hyperhydricity. The best immersion cycle (time and frequency) was proven to have the shortest daily immersion time (6 min every 24 h) which ensured good levels of relative growth and multiplication rate, very limited onset of hyperydricity, and the longest shoots, promoting direct rooting after only 30 days of culture. In comparison with the semisolid culture, the TIS culture resulted in an increase of the total phenolic content (TPC) and in a lower value of the total flavonoid content (TFC). However, considering the higher quantity of biomass produced in the Plantformâ„¢ bioreactor, the difference in terms of TFC productivity between semisolid medium and TIS liquid culture was proven to be statistically equivalent
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