food chain

食物链
  • 文章类型: Journal Article
    脱氧雪腐镰刀菌烯醇(DON)及其衍生物3-乙酰脱氧雪腐镰刀菌烯醇(3-Ac-DON)和15-乙酰脱氧雪腐镰刀菌烯醇(15-Ac-DON)在整个小麦加工链中的分布通过一对一进行了系统评估整个加工链的相应研究。通过液相色谱-质谱(LC-MS/MS)测定小麦籽粒和相应麦麸中的DON及其衍生物,小麦粉,以及以小麦粉为基础的半成品和成品。这项研究表明,将小麦谷物加工成小麦面粉可使DON的水平显着降低约52.7%-68.2%。以小麦粉为基础的产品的小麦粉加工使DON浓度降低了约7.0%-70.6%。在处理方法中,饼干产量下降幅度最大(70.6%)。小麦籽粒和麦麸中3-Ac-DON和15-Ac-DON含量较低的DON同时出现的频率明显高于小麦粉。对于以小麦粉为基础的产品,在使用严重污染DON的谷物制备的加工小麦粉产品中,只能观察到3-Ac-DON的分布模式。在中国,据我们所知,首次系统评价了小麦粉和小麦粉制品中DON的加工因素。小麦粉的DON平均PF为0.35,小麦粉产品的平均PF为0.37-0.84,饼干的PF最小(0.37),表明DON在饼干制作中显著减少。此外,DON的饮食暴露评估表明,中国消费者的整体健康风险可接受,在婴儿和幼儿中观察到最高的暴露。本研究为我国小麦及其各类产品DON限量的分类管理提供了重要参考。
    The distribution of deoxynivalenol (DON) and its derivatives 3-acetyldeoxynivalenol (3-Ac-DON) and 15-acetyldeoxynivalenol (15-Ac-DON) throughout the wheat processing chain were systemically evaluated by one-to-one corresponding studies of the whole processing chain. DON and its derivatives were determined by liquid chromatography-mass spectrometry (LC-MS/MS) in wheat grains and corresponding wheat bran, wheat flour, and semi-finished and finished wheat flour-based products. This investigation showed that wheat grain processing to wheat flour significantly decreased the levels of DON by approximately 52.7%-68.2%. Wheat flour processing of wheat flour-based products decreased the DON concentration by approximately 7.0%-70.6%. Among the processing methods, biscuit making showed the largest reduction (70.6%). The co-occurrence frequency of DON with low levels of 3-Ac-DON and 15-Ac-DON was significantly greater in wheat grains and wheat bran than in wheat flour. For wheat flour-based products, only the distribution pattern of 3-Ac-DON was observable in processed wheat flour products prepared using grains heavily contaminated with DON. In China, to the best of our knowledge, the processing factors (PFs) of DON in wheat flour and wheat flour-based products were systematically evaluated for the first time. The average PF of DON was 0.35 for wheat flour and the average PFs were 0.37-0.84 for wheat flour-based products, with biscuits having the smallest PF (0.37), indicating DON significantly decreasing in biscuit making. Furthermore, dietary exposure assessment of DON indicated an acceptable overall health risk in Chinese consumers, with the highest exposure being observed in infants and young children. This study provides important references for classified management of DON limits in wheat and its various products in China.
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  • 文章类型: Journal Article
    淡水系统中微塑料的存在会对食物链产生有害影响。浮游动物,特别是悬浮液和过滤给料机,可以摄取微塑料,这会造成不良影响,并将其转移到更高的营养水平。这里,我们分析存在,丰度,以及微塑料在地表水中的分布,浮游动物,在墨西哥中部的两个热带湖泊里钓鱼.我们在每个湖泊的三个地点和Chirostoma属的120条鱼收集了一式三份的水样。从每个水样中,随机分离并独立加工300只轮虫和150只微甲壳类动物。在水中发现的颗粒中,浮游动物,和来自两个湖泊的鱼,碎片是主要的碎片。两个湖泊的水柱中微塑料的总丰度在1.2至17.0项L-1之间变化。在浮游动物中,发现的碎片主要含有多达0.1项ind-1,而在鱼类中,记录了多达4.5项ind-1。我们的结果证实了淡水体食物网的不同隔室中存在微塑料,水柱,浮游动物,和鱼。需要进一步研究这些压力源在不同营养水平上的可能影响。
    The presence of microplastics in freshwater systems can have harmful effects on the food chain. Zooplankton, especially suspension and filter feeders, can ingest microplastics, which can cause adverse effects and transfer them to higher trophic levels. Here, we analyze the presence, abundance, and distribution of microplastics in surface water, zooplankton, and fish in two tropical lakes in central Mexico. We collected water samples in triplicate at three sites in each lake and 120 fish of the genus Chirostoma. From each water sample, 300 rotifers and 150 microcrustaceans were randomly isolated and processed independently. Of the particles found in the water, zooplankton, and fish from both lakes, the fragments were the predominant ones. The total abundance of microplastics in the water column of both lakes varied between 1.2 and 17.0 items L-1. In zooplankton, fragments were found predominantly with up to 0.1 items ind-1, while in fish, up to 4.5 items ind-1 was recorded. Our results confirm the presence of microplastics in different compartments of the food webs of freshwater bodies, water column, zooplankton, and fish. Further work is required on the possible effects of these stressors at the different trophic levels.
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  • 文章类型: Journal Article
    异养细菌和古细菌(原核生物)是海洋食物网和全球生物地球化学循环的主要组成部分。然而,对原核生物在全球环境梯度中的变化了解有限,以及它们的全球丰度和代谢活动(生产和呼吸)如何受到气候变化的影响。利用原核生物丰度的全球数据集,细胞碳和代谢活性我们揭示了平均原核生物生物量在全球海洋表面变化不到3倍,从极地到热带沿海和上升流地区,原核生物的总代谢活性增加了一个以上的数量级。在气候变化下,全球地表水中的原核生物生物量预计每摄氏度变暖将下降约1.5%,而原核呼吸将增加~3.5%(~0.85PgCyr-1)。原核生物生物量下降的速度是浮游动物和鱼类的三分之一,而原核呼吸的增加速率是两倍。这表明未来,温暖的海洋可能越来越多地由原核生物主导,将越来越多的初级生产转移到微生物食物网中,远离较高的营养水平,并降低深海固碳的能力,其他一切都平等。
    Heterotrophic Bacteria and Archaea (prokaryotes) are a major component of marine food webs and global biogeochemical cycles. Yet, there is limited understanding about how prokaryotes vary across global environmental gradients, and how their global abundance and metabolic activity (production and respiration) may be affected by climate change. Using global datasets of prokaryotic abundance, cell carbon and metabolic activity we reveal that mean prokaryotic biomass varies by just under 3-fold across the global surface ocean, while total prokaryotic metabolic activity increases by more than one order of magnitude from polar to tropical coastal and upwelling regions. Under climate change, global prokaryotic biomass in surface waters is projected to decline ~1.5% per °C of warming, while prokaryotic respiration will increase ~3.5% ( ~ 0.85 Pg C yr-1). The rate of prokaryotic biomass decline is one-third that of zooplankton and fish, while the rate of increase in prokaryotic respiration is double. This suggests that future, warmer oceans could be increasingly dominated by prokaryotes, diverting a growing proportion of primary production into microbial food webs and away from higher trophic levels as well as reducing the capacity of the deep ocean to sequester carbon, all else being equal.
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  • 文章类型: Journal Article
    微生物,转基因与否,可以在食物链中用作活性剂,生物质或作为感兴趣物质的生产生物体。此类微生物或其衍生物质/产品在欧洲市场的放置可能需要经过上市前授权程序。授权过程需要进行风险评估,以确定微生物在食物链中使用时的安全性和/或功效,作为生物质或生产菌株。这包括所评估的微生物的完整分子表征。对于某些受管制的产品,微生物的全基因组序列(WGS)数据的使用被确立为风险评估的要求。在这方面,从WGS分析获得的数据可以提供有关菌株的明确分类学鉴定的信息,关于关注基因的存在(例如编码毒力因子的基因,对人类和动物的临床相关抗菌药物的耐药性,有害代谢物或临床相关抗菌剂的产生)以及遗传修饰的表征(在相关的情况下)。本文件为申请人提供了有关如何在受管制产品的市场授权申请中描述和报告WGS分析结果的建议。给出了如何进行基因组测序和应达到的质量标准/阈值的指示,以及需要报告的数据和相关信息,如果需要。这份更新的文件取代了EFSA2021声明,反映了目前用于生成和分析WGS数据以进行微生物风险评估的技术和方法方面的知识。
    Microorganisms, genetically modified or not, may be used in the food chain either as active agents, biomasses or as production organisms of substances of interest. The placement of such microorganisms or their derived substances/products in the European market may be subject to a premarket authorisation process. The authorisation process requires a risk assessment in order to establish the safety and/or the efficacy of the microorganism(s) when used in the food chain as such, as biomasses or as production strains. This includes a full molecular characterisation of the microorganism(s) under assessment. For certain regulated products, the use of whole genome sequence (WGS) data of the microorganism is established as a requirement for the risk assessment. In this regard, data obtained from WGS analysis can provide information on the unambiguous taxonomic identification of the strains, on the presence of genes of concern (e.g. those encoding virulence factors, resistance to antimicrobials of clinical relevance for humans and animals, production of harmful metabolites or of clinically relevant antimicrobials) and on the characterisation of genetic modification(s) (where relevant). This document provides recommendations to applicants on how to describe and report the results of WGS analyses in the context of an application for market authorisation of a regulated product. Indications are given on how to perform genome sequencing and the quality criteria/thresholds that should be reached, as well as the data and relevant information that need to be reported, if required. This updated document replaces the EFSA 2021 Statement and reflects the current knowledge in technologies and methodologies to be used to generate and analyse WGS data for the risk assessment of microorganisms.
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  • 文章类型: Journal Article
    随机食物链模型是生态学研究领域中的一个重要模型。由于现有模型难以描述交叉扩散和随机因素对物种种群演化的影响,这项工作涉及具有猎物-出租车的随机交叉扩散三物种食物链模型,其中捕食者的运动方向与猎物的梯度相反,即,更高密度的猎物。利用随机Galerkin逼近方法在Hilbert空间中建立了martingale解的存在性和唯一性。密封性标准,Jakubowski对Skorokhod定理的推广,和维塔利收敛定理。此外,研究了时间平均意义下随机交叉扩散三物种食物链模型稳态的渐近行为。最后,进行了数值模拟,以说明我们的分析结果。
    The stochastic food chain model is an important model within the field of ecological research. Since existing models are difficult to describe the influence of cross-diffusion and random factors on the evolution of species populations, this work is concerned with a stochastic cross-diffusion three-species food chain model with prey-taxis, in which the direction of predators\' movement is opposite to the gradient of prey, i.e., a higher density of prey. The existence and uniqueness of martingale solutions are established in a Hilbert space by using the stochastic Galerkin approximation method, the tightness criterion, Jakubowski\'s generalization of the Skorokhod theorem, and the Vitali convergence theorem. Furthermore, asymptotic behaviors around the steady states of the stochastic cross-diffusion three-species food chain model in the time mean sense are investigated. Finally, numerical simulations are carried out to illustrate the results of our analysis.
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  • 文章类型: Journal Article
    背景:生物强化被认为是一种可持续且具有成本效益的方法,可以恢复受污染的环境,但它的结果是高度可变的。捕食是影响接种物建立的自上而下的关键控制机制,然而,它对这一过程的影响很少受到关注。这项研究的重点是营养相互作用对两种具有不同污染暴露历史的土壤中生物强化成功的影响。我们在这些土壤中接种了13C标记的污染物降解财团,并通过DNA的稳定同位素探测(SIP)追踪了标记生物质的命运。我们通过16SrRNA和18SrRNA基因的扩增子测序与新型富集因子计算相结合,鉴定了活性细菌和真核接种物-生物质消费者。
    结果:接种在短期内有效地提高了PAH的去除,但不是在长期污染的土壤中。在长期污染的土壤中,第15天已经观察到接种属的相对丰度下降,虽然在短期污染的土壤中观察到这些属的生长,表明接种物的建立。在这两种土壤中,真核细胞属主要是13C标记生物质的早期掺入物,而细菌在培育期结束时掺入了标记的生物质,可能是通过交叉喂食。我们还发现两种土壤之间的演替模式不同。在短期污染的土壤中,Cercozoa和真菌属以早期掺入者为主,而Ciliophora,在长期污染的土壤中,Ochrophyta和Amoebozoa是主要属。
    结论:我们的结果显示了接种物建立和捕食者群落反应的差异,影响生物强化效率。这凸显了需要进一步研究捕食对接种物存活的影响,以增加基于接种的技术的适用性。视频摘要。
    BACKGROUND: Bioaugmentation is considered a sustainable and cost-effective methodology to recover contaminated environments, but its outcome is highly variable. Predation is a key top-down control mechanism affecting inoculum establishment, however, its effects on this process have received little attention. This study focused on the impact of trophic interactions on bioaugmentation success in two soils with different pollution exposure histories. We inoculated a 13C-labelled pollutant-degrading consortium in these soils and tracked the fate of the labelled biomass through stable isotope probing (SIP) of DNA. We identified active bacterial and eukaryotic inoculum-biomass consumers through amplicon sequencing of 16S rRNA and 18S rRNA genes coupled to a novel enrichment factor calculation.
    RESULTS: Inoculation effectively increased PAH removal in the short-term, but not in the long-term polluted soil. A decrease in the relative abundance of the inoculated genera was observed already on day 15 in the long-term polluted soil, while growth of these genera was observed in the short-term polluted soil, indicating establishment of the inoculum. In both soils, eukaryotic genera dominated as early incorporators of 13C-labelled biomass, while bacteria incorporated the labelled biomass at the end of the incubation period, probably through cross-feeding. We also found different successional patterns between the two soils. In the short-term polluted soil, Cercozoa and Fungi genera predominated as early incorporators, whereas Ciliophora, Ochrophyta and Amoebozoa were the predominant genera in the long-term polluted soil.
    CONCLUSIONS: Our results showed differences in the inoculum establishment and predator community responses, affecting bioaugmentation efficiency. This highlights the need to further study predation effects on inoculum survival to increase the applicability of inoculation-based technologies. Video Abstract.
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  • 文章类型: Journal Article
    在北极的架子上,底栖食物网与上覆的初级生产紧密相连。在季节性冰区,交感(与冰相关的)初级生产可能是生产性流入架上底栖动物的主要碳源。然而,交感有机物质的作用在冰层覆盖严重的食物网中不太清楚,生产率低的流出货架,比如格陵兰岛东北部的架子。高度支化的类异戊二烯生物标志物(HBIs)用于跟踪水柱中交感和中上层有机物的相对分布,沉积物,和东北格陵兰陆架和峡湾的底栖动物。整个研究区域的中上层HBI含量较低,表明中上层硅藻的产量普遍较低(在采样时)。这反映在底栖生物上,据估计,它们的约90%的同化碳来自交感神经源,表明底栖食物网高度依赖同情生产。沿海地区的这种依赖程度高于开放式架子,潜在的更高的中上层生产力和河岸上较浅的水可能会增加中上层有机物的贡献。由于预计北极架子上的冰盖减少和快速下沉的冰藻产量减少,可能会导致冰藻与底栖动物之间的耦合减弱,可能对未来的底栖群落结构和功能产生影响。
    On Arctic shelves, benthic food-webs are tightly linked to overlying primary production. In the seasonal ice zone, sympagic (ice-associated) primary production can be a major source of carbon for the benthos on productive inflow shelves. However, the role of sympagic organic matter is less well-understood in food webs of heavily ice-covered, less- productive outflow shelves, such as the northeast Greenland shelf. Highly branched isoprenoid biomarkers (HBIs) were used to track the relative distribution of sympagic and pelagic organic matter in the water column, sediments, and benthic fauna of the northeast Greenland shelf and fjords. Low pelagic HBI presence throughout the study area indicated a generally low production by pelagic diatoms (at the time of sampling). This was reflected in the benthos, as ~90% of their assimilated carbon was estimated to come from sympagic sources, indicating a benthic food-web highly reliant on sympagic production. This reliance was higher in coastal areas than on the open shelf, where the potentially higher pelagic productivity and shallower water on banks likely increased contributions of pelagic organic matter. As declining ice cover and reduced production of fast-sinking ice algae projected for Arctic shelves will likely result in weaker coupling between ice algae and the benthos, with possible consequences for future benthic-community structure and function.
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  • 文章类型: Journal Article
    捕食者对变暖的反应可以通过表型可塑性发生,进化适应或两者的结合,改变它们对猎物群落的自上而下的影响。然而,我们缺乏气候变暖引起的捕食者进化变化如何影响天然食物网的证据.这里,我们询问,与经历自然热状态的附近物种相比,多代受变暖影响的野生鱼类对猎物群落的影响是否不同。我们用幼虫鲈鱼(Percafluviatilis)进行了普通的花园中观实验,源自加热或参考沿海环境,在实验温度的梯度下,以浮游动物群落为食。总的来说,在加热鱼的存在下,浮游动物的丰度更高,并且没有随着实验变暖而变化,而在存在未加热来源的鱼的情况下,随着实验温度的下降。浮游动物分类学和大小组成的响应表明,随着温度的升高,加热来源的幼虫消耗更多的大型类群。我们的发现表明,鱼类种群之间的差异,可能代表对其长期热环境的适应,会影响丰度,生物量,猎物群落的大小和物种组成。这表明,捕食者对持续气候变暖的快速微进化可能会通过食物网传播产生间接的跨代生态后果。
    Predator responses to warming can occur via phenotypic plasticity, evolutionary adaptation or a combination of both, changing their top-down effects on prey communities. However, we lack evidence of how warming-induced evolutionary changes in predators may influence natural food webs. Here, we ask whether wild fish subject to warming across multiple generations differ in their impacts on prey communities compared with their nearby conspecifics experiencing a natural thermal regime. We carried out a common garden mesocosm experiment with larval perch (Perca fluviatilis), originating from a heated or reference coastal environment, feeding on zooplankton communities under a gradient of experimental temperatures. Overall, in the presence of fish of heated origin, zooplankton abundance was higher and did not change with experimental warming, whereas in the presence of fish of unheated origin, it declined with experimental temperature. Responses in zooplankton taxonomic and size composition suggest that larvae of heated origin consume more large-sized taxa as the temperature increases. Our findings show that differences between fish populations, potentially representing adaptation to their long-term thermal environments, can affect the abundance, biomass, size and species composition of their prey communities. This suggests that rapid microevolution in predators to ongoing climate warming might have indirect cross-generational ecological consequences propagating through food webs.
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  • 文章类型: Journal Article
    葡萄糖是在所有动物类群中用作能量来源的中心代谢化合物。分类群之间的葡萄糖浓度有很高的种间差异,其起源和后果在很大程度上仍然未知。营养可能会影响葡萄糖浓度,因为不同食物来源的碳水化合物含量可能决定生物体中代谢途径的重要性。鸟类维持高葡萄糖浓度,这可能带来氧化损伤的风险。我们从171种科学出版物中收集了202种鸟类的葡萄糖浓度和生活史数据,将它们分为七个营养协会,并用系统发育控制模型分析数据。我们表明,葡萄糖浓度与体重呈负相关,并且与具有中等系统发育信号的营养协会显着相关。控制异速测后,食肉鸟类的葡萄糖浓度最高,它们依靠高糖异生率来维持血糖,最低的是食果/蜜食物种,直接摄入碳水化合物。然而,不同葡萄糖浓度的营养行会的寿命没有差异。这些结果将营养生态学与生理学联系起来,并表明在宏观进化尺度上,需要不断升高葡萄糖浓度的物种可能会有额外的适应措施,以避免与高血糖相关的风险。
    Glucose is a central metabolic compound used as an energy source across all animal taxa. There is high interspecific variation in glucose concentration between taxa, the origin and the consequence of which remain largely unknown. Nutrition may affect glucose concentrations because carbohydrate content of different food sources may determine the importance of metabolic pathways in the organism. Birds sustain high glucose concentrations that may entail the risks of oxidative damage. We collected glucose concentration and life-history data from 202 bird species from 171 scientific publications, classified them into seven trophic guilds and analysed the data with a phylogenetically controlled model. We show that glucose concentration is negatively associated with body weight and is significantly associated with trophic guilds with a moderate phylogenetic signal. After controlling for allometry, glucose concentrations were highest in carnivorous birds, which rely on high rates of gluconeogenesis to maintain their glycaemia, and lowest in frugivorous/nectarivorous species, which take in carbohydrates directly. However, trophic guilds with different glucose concentrations did not differ in lifespan. These results link nutritional ecology to physiology and suggest that at the macroevolutionary scale, species requiring constantly elevated glucose concentrations may have additional adaptations to avoid the risks associated with high glycaemia.
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  • 文章类型: Journal Article
    有机磷酸酯(OPEs)已被广泛生产和使用,而对它们在食物链中的发生和潜在来源知之甚少。在这项研究中,生牛奶,奶牛喝水,饲料是从中国各地的牧场收集的,和OPEs进行了测试,以探索OPEs在食物链中的发生和传播,并通过某些食物消费进一步评估奶牛和人类的每日OPE摄入量。原料乳中∑OPEs(15OPEs之和)的中位数水平为2140pg/mL,磷酸三(1-氯-2-丙基)酯(TCIPP)是最丰富的OPE。除磷酸三乙酯(TEP)外,水中的OPEs水平低于原奶,而饲料中大多数OPEs的水平明显高于原奶(按干重调整)。奶牛通过饲料摄入的OPEs估计为2530ng/kgbw/天,远高于水(742纳克/千克体重/天),表明饲料是更关键的暴露源。对于液态奶消费者来说,在3-17岁和成人中,∑15OPE的高暴露(第95位)估计每日摄入量(EDI)分别为20和7.11ng/kgbw/天,分别,很明显,奶牛的OPE摄入量要重得多。最后,计算的危害指数(HIs)表明,通过食用牛奶摄入OPEs不会对中国人口构成重大健康风险。
    Organophosphate esters (OPEs) have been widely produced and used, while little is known about their occurrence in the food chain and potential sources. In this study, raw cow milk, cow drinking water, and feed were collected from pastures across China, and OPEs were tested to explore the occurrence and transmission of OPEs in the food chain and to further assess daily OPE intakes for cows and humans via certain food consumption. The median level of ∑OPEs (sum of 15 OPEs) in raw milk was 2140 pg/mL, and tris(1-chloro-2-propyl) phosphate (TCIPP) was the most abundant OPE. Levels of OPEs in water were lower than those in raw milk except for triethyl phosphate (TEP), while levels of most OPEs in feed were significantly higher than those in raw milk (adjusted by dry weight). The estimated dietary intake of OPEs via feed for cows was 2530 ng/kg bw/day, which was much higher than that via water (742 ng/kg bw/day), indicating that feed was a more critical exposure source. For liquid milk consumers, the high-exposure (95th) estimated daily intakes (EDIs) of ∑15OPE were 20 and 7.11 ng/kg bw/day for 3-17 years and adults, respectively, and it is obvious that cows had much heavier OPE intake. Finally, the calculated hazard indexes (HIs) suggested that the intake of OPEs via cow milk consumption would not pose significant health risks to the Chinese population.
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