Food choice and reproductive success of Folsomia candida feeding on copper-contaminated mycelium of the soil fungus Alternaria alternata

We examined collembolan food preference for fungal mycelium grown on copper-contaminated medium, and the relationship between copper content, food selectivity and collembolan fitness when fed contaminated mycelium.To clarify whether collembolan food selectivity is related to fitness parameters, Folsomia candida were fed mycelium of the dark-pigmented fungus Alternaria alternata grown on medium with different copper concentrations. Copper-contaminated food (fungus grown on 50, 125, 250 and 500 μg Cu g⁻¹ medium, fresh wt.) was offered together with untreated food for 4 weeks. F. candida fed selectively on the provided mycelium and discriminated clearly between mycelium grown on high and low levels of contamination, distinctly preferring fungus grown on medium with a total copper concentration of 50 and 125 μg g⁻¹. In contrast, fungus grown on highly contaminated medium (250 and 500 μg g⁻¹) was avoided. Collembolan food preference generally matched fitness parameters. Reproduction was significantly affected by the total copper concentration of the fungal growth medium. When fed their preferred mycelium, collembolan reproduction was enhanced, whereas a diet of highly contaminated mycelium (250 or 500 μg g⁻¹) resulted in a strong decrease in reproduction. Adult survival was affected only marginally. Even though heavy metal contamination is a potential stress factor for many soil microarthropods, F. candida is able to discriminate between high and low quality food sources, and even benefits from moderately elevated copper concentrations.     

The fat that matters: Soil food web analysis using fatty acids and their carbon stable isotope signature

Chemical taxonomy based upon the composition of lipids is widely applied to investigate microbial communities and fatty acids have recently been employed to connect soil microbial and faunal food webs as well as to elucidate functional groups at higher trophic levels. The additional use of compound-specific isotopic analysis of ¹³C/¹²C ratios in fatty acids allows assessing specific trophic links and belowground carbon fluxes. In this review systematic patterns and processes underlying variations in the composition of fatty acids and their ¹³C/¹²C ratio are described. The emphasis is on biomarker fatty acids, their incorporation and modification, effects of pool size, and analytical methods. Further development of the application of fatty acid profiling to soil ecology should include both advances in experimental research and growth of theory. Accordingly, areas in which future experimentation can lead to progress in soil food web analysis are identified. Overall, combining fatty acid biomarker and their isotopic ratios will allow detailed insight into belowground trophic interactions.     

Characteristics and motivations of potential users of urban allotment gardens: The case of Vila Nova de Gaia municipal network of urban allotment gardens

Demand for urban allotment plots has recently increased in Portugal but little is known about the characteristics and motivations of the demanding population, and if and how its characteristics affect its motivations.In this article, we use the Municipal Network of Urban Allotment Gardens (MNUAG)¹ launched by the Portuguese municipality of Vila Nova de Gaia for an exploratory Case Study research. Based on the data collected in the MNUAG application forms submitted in the period 2012–2013, we describe the characteristics and the motivations of the population demanding for urban allotment gardens (UAG)² and run a logit model to find if and how the motivations are influenced by the characteristics.The population of applicants to the MNUAG is quite diverse. It has a balanced gender distribution and an average age of 47 years. Most of the applicants are between 25 and 64 years old, and belong to households with 2–4 members.To supplement family budget, occupation of leisure times, and access to organic farming are its most important motivations, followed by environmental concerns, the practice of physical exercise, and education.Motivations are influenced by the characteristics. This study has identified two groups of applicants with contrasting motivations. Food security is the only significant motivation for the unemployed and low-income applicants. Food safety, health concerns, environmental concerns, recreation, and education are common and frequent motivations among the upper and intermediate professional groups.Results can have future implications on the MNUAG, namely on the UAG location and typology, plot number, and plot size. To meet the demand of all the types of applicants, while fostering social cohesion, the municipality should reinforce its current small UAG structure and add to the MNUAG one or two productive parks.     

食品脱氧剂配比的优化

[目的]探寻最佳脱氧效果的食品脱氧剂。[方法]对比不同配比的铁系脱氧剂在相同条件下的脱氧效果并比较铁粉活化程度对脱氧效果的影响。[结果]配比为0.3 g活化铁粉、0.1 g硅藻土、1 g Na2CO3.10H2O、0.2 g NaCl时脱氧效果最好。[结论]通过该实验获得了最佳脱氧效果的食品脱氧化剂配比。     

高职《动物性食品卫生检验》课程教学方式的改革

《动物性食品卫生检验》作为一门畜牧兽医、动物防疫与检疫专业的主干课程,具有专业性和实践性强的特点,为了提高学生对食品卫生检验的基础理论、实践技能和食品安全系统控制理念,从教学效果着手提出改革的思路,利用现有的资源充分发掘学生的学习积极性和实践动手能力,重视强化基本技能的训练,取得了一定的效果。     

果蔬表面静电涂敷试验研究

在前期高压电极结构试验和静电涂敷模拟试验的基础上，进行了单负高压电极静电涂敷试验、双负高压电极静电涂敷试验和保鲜试验，测试了涂敷系数、涂层径向角、涂敷效率和涂层表观质量等参数。结果证明，采用栅网式静电涂敷方法的果蔬表面静电涂敷可以在一定直径范围的果蔬表面进行，并有很好的应用前景。     

水力旋流器在食品工业中的应用

从水力旋流器的基本结构和工作原理出发，综合评述了水力旋流器在食品工业中具有代表性的应用情况，进而指出，随着科学技术的发展和对其研究的不断深入，水力旋流器将在食品工业领域发挥更为重要作用。     

广东省食用豆类种质资源的创新利用与前瞻

对中国特别是广东省食用豆类种质资源创新利用的意义、国内外创新利用的情况、进一步创新利用的内容方向、前景等进行了综述介绍和前瞻思考,指出食用豆类种质资源创新利用应加强种质资源收集和创新、新品种选育及繁种、配套栽培技术研究以及传统加工制作模式改进工作,同时应选育蛋白质含量高、抗病虫害能力强、专用型、耐贮运的品种。     

生态农业与食品安全

食品安全已引起国内外的广泛关注。我国食品安全与提高人民生活质量、保证人民健康,维护社会稳定、建设和谐社会等密切相关。维护食品安全,就是维护生态安全、维护经济安全、维护国家安全。目前,我国食品安全面临的主要问题,一是食品数量不足,合格率不高;二是食品中有毒有害物质残留量高,食物中毒事件增多;三是资源、生态、环境问题突出,食品可持续生产能力面临潜在威胁;四是食品安全的法律、法规尚不健全,执法与管理力度不够。生态农业是当今社会农业发展的重要方向,具有显著的增产、增收、增效和环境保护功能,对改善和优化农业生态环境、生产健康优质的安全食品具有重大意义。生态农业在解决当前及今后我国面临的食品数量、质量安全及食品可持续生产能力等方面,将发挥着重要与不可替代的作用。为保障新世纪我国的食品安全,必须大力发展生态农业。主要措施包括:提高对生态农业的认识;大力普及生态农业知识;全面应用与推广生态农业技术;加强生态农业的科学研究;重视实行生态农业的产业化。     

Modeling trophic pathways, nutrient cycling, and dynamic stability in soils

Soil communities are compartmentalized into pathways of trophic interactions and nutrient flows that originate from plant roots, bacteria and fungi. The pathways differ in terms of the organisms that comprise them, the habitats that the organisms occupy and the rates by which the organisms process and transfer material and energy. The fungi, nematodes and arthropods within the fungal pathway live in air-filled pore spaces and water films, while the bacteria, protozoa, and nematodes within the bacterial pathway occupy water-filled pore spaces and water films. Organisms within the fungal pathway have longer generation times and process matter at slower rates than those within the bacterial pathway. Empirical studies have shown that under natural conditions the pathways co-exist in a stable manner. The relative sizes (indexed by the densities of organisms) and activities (indexed by nutrient-flow rates, excretion rates and respiration rates) of the pathways may change seasonally and in response to minor disturbances, but they persist. However, large anthropogenic and natural disturbances induce shifts in the relative sizes and activities of the pathways. Coincident with these shifts are reports of changes in the aboveground plant community and the availability and retention of plant limiting nutrients. We developed simple models of the bacterial and fungal pathways to explore the consequences of the observed shifts on the dynamic stability of the system. The more stable configurations occurred when there was a balance in the flow of nutrients between the two pathways. Large shifts in nutrient cycling and community structure towards either the fungal pathway or toward the bacterial pathway resulted in less stable or unstable configurations.