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501.
Similar to other marine holobionts, fish are colonized by complex microbial communities that promote their health and growth. Fish-associated microbiota is emerging as a promising source of bioactive metabolites. Pleuronectes platessa (European plaice, plaice), a flatfish with commercial importance, is common in the Baltic Sea. Here we used a culture-dependent survey followed by molecular identification to identify microbiota associated with the gills and the gastrointestinal tract (GIT) of P. platessa, then profiled their antimicrobial activity and metabolome. Altogether, 66 strains (59 bacteria and 7 fungi) were isolated, with Proteobacteria being the most abundant phylum. Gill-associated microbiota accounted for higher number of isolates and was dominated by the Proteobacteria (family Moraxellaceae) and Actinobacteria (family Nocardiaceae), whereas Gram-negative bacterial families Vibrionaceae and Shewanellaceae represented the largest group associated with the GIT. The EtOAc extracts of the solid and liquid media cultures of 21 bacteria and 2 fungi representing the diversity of cultivable plaice-associated microbiota was profiled for their antimicrobial activity against three fish pathogens, human bacterial pathogen panel (ESKAPE) and two human fungal pathogens. More than half of all tested microorganisms, particularly those originating from the GIT epithelium, exhibited antagonistic effect against fish pathogens (Lactococcus garvieae, Vibrio ichthyoenteri) and/or human pathogens (Enterococcus faecium, methicillin-resistant Staphylococcus aureus). Proteobacteria represented the most active isolates. Notably, the solid media extracts displayed higher activity against fish pathogens, while liquid culture extracts were more active against human pathogens. Untargeted metabolomics approach using feature-based molecular networking showed the high chemical diversity of the liquid extracts that contained undescribed clusters. This study highlights plaice-associated microbiota as a potential source of antimicrobials for the control of human and the aquaculture-associated infections. This is the first study reporting diversity, bioactivity and chemical profile of culture-dependent microbiota of plaice. 相似文献
502.
The development of red color in the peel of red Chinese sand pears (Pyrus pyrifolia Nakai) is influenced by temperature and light; however, the response patterns vary among different cultivars. In this study, we systematically investigated the influence of postharvest treatment with various temperatures (low, high, variant and constant) on detached mature fruit of red Chinese sand pear ‘Mantianhong’ and ‘Meirensu’. Fruit of red apple (Malus domestica Borkh.) ‘Royal Gala’ and red European pear (P. communis L.) ‘Cascade’ received the same treatments for comparison. Furthermore, the effects of light quality and irradiance level on ‘Mantianhong’ pears were evaluated at the optimum temperature for anthocyanin accumulation. Fruit firmness and concentrations of total soluble sugars and organic acids were measured to determine fruit quality. The effect of temperature on red Chinese sand pear fruit color was similar to that of apples, but not European pear. Moreover, low temperature more effectively induced red coloration in ‘Mantianhong’ and ‘Meirensu’ pears than high temperature; anthocyanin levels increased with increasing irradiance level from 0 to 532 μmol m−2 s−1, and UV-B and visible light synergistically improved the red color of the fruit. Therefore, a combination of low temperature and high intensity of UV-B/visible light could improve the postharvest coloration of red sand pear fruit. The results will contribute to an improved understanding of the mechanism responsible for the coloration of red Chinese sand pears and will aid development of new techniques to improve color in postharvest fruit. 相似文献
503.
欧盟国家兽药残留数据库介绍 总被引:1,自引:0,他引:1
比利时建立的兽药残留数据库中包括分析方法库,该库提供了1份经过评估的兽药残留分析方法清单,其中的方法经验证后可以考虑作为候选标准.根据这些方法与欧盟委员会决议93/256/EEC和93/257/EEC规范要求的符合程度,可将方法分为高可靠性和有限可靠性.另外,这个数据库还包括有关消费者健康的药物毒理数据,比利时肉类消费的估算数据,欧洲和比利时关于动物产品中残留的法规库,市场上可获得的检测试剂(抗血清、免疫诊断试剂盒、放射性及同位素示踪试剂等),有关比利时兽医检查所和农业部实施监控计划中的定量和定性数据,有关动物性食品中存在残留物质的理化参数,等等.这个数据库已在因特网上公开,可免费查询相关资料,互联网上的地址为:http://cemu10.fmv.ulg.ac.be/OSTC. 相似文献
504.
提供了一种基于自适应拉普拉斯变换有限差分方法来解决Black-Scholes 期权定价问题.相比较于传统的时间推进法,此方法在保证较高精确度和很好的收敛性的同时,还可以减少计算时间.这一精确有效的方法将通过数值实验来验证. 相似文献
505.
Daniel Sacristn Blai Pearroya Luis Recatal 《Land Degradation \u0026amp; Development》2015,26(6):587-595
This paper increases the knowledge on the potential use of Cu‐contaminated agricultural soils with tomato (Solanum lycopersicum L.). The effect of Cu and its interaction with soil properties on plant biomass production and on the accumulation of this metal in plant tissues were evaluated by conducting biomass assays in four representative Mediterranean agricultural soils contaminated by Cu. Copper toxicity on plant biomass production, evaluated through the effective concentrations of Cu added to soil that reduce the biomass production by 50% (EC50) and by 10% (EC10), was higher in soils having less soil organic matter and clay content and even in soils with favourable properties but having salinity. For the cases in which tomato was collected, Cu concentrations in them were similar for all soils and doses and never exceed the maximum Cu concentration allowed by the Codex Alimentarius Commission Regulation (10 mgCu kg−1 in fresh weight basis). According to our results, tomato could be cropped in Cu‐contaminated Mediterranean agricultural soils when concentrations of Cu determined in them rely between their respective EC50 and EC10, because production and quality of fruits, the latter understood as the Cu concentration in them, would not be compromised. For the soils assayed, these values would range between 32·9 and 1696·5 mg kg−1, depending on soil properties. Because the baseline value considered is similar to those established in other parts of the European Mediterranean region, these results can be used as guidance for this region to establish adequate phytoremediation strategies and prevent land degradation processes. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
506.
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