植物提取物微生物限量标准及检测技术进展

植物提取物的微生物检测是保证植物产品安全性的重要手段, 制定严格的植物提取物质量控制标准体系, 特别是功能性食品、食品添加剂和植物源日用化学品等产品中微生物的检测和控制, 对产品的质量及安全保证具有重要作用, 是影响植物提取业实现全面发展的关键问题。本文主要介绍了部分国家植物提取物的微生物限量标准和植物提取物微生物检测的国内外现状与发展趋势, 并就如何建立植物提取物微生物检测行业标准体系提出了若干建议。希望对我国植物提取业实现新时期跨越式发展提供参考。     

水环境毒物污染点源的生态风险管理现状与展望

评述了发达国家和我国在这一领域的进展和前景。目前国内外常用的基于水质标准／废水排放标准的特征化学污染物法,并不能有效控制组分复杂的废水中的有机毒物排放。因此,仅应用这一传统方法对水环境有机毒物污染点源难以实现有效的生态风险管理。同时采用全废水的生态毒性法可就弥补这一缺陷,根据生态风险管理要求可有效控制组份复杂的废水中有毒有机污染物的排放。鉴别出导致废水生态毒性的关键有机毒物的毒性鉴别评价,是毒物污染点源的生态风险管理核心。本文还对毒性鉴别评价方法学的发展以及全废水毒性法应用于我国水环境毒物污染点源生态风险管理的前景作了评述。     

有机酸存在下小麦体内Cd的生物毒性和植物络合素(PCs)合成的关系

采用溶液培养方式 ,研究了有机酸存在下小麦体内 Cd的生物毒性和植物络合素 (PCs)合成的相关关系 ,试图寻求一种与小麦体内 Cd的生物毒性高度相关的评价指标。结果显示 ,Cd胁迫对小麦产生明显的毒害效应并诱导小麦根系内 PCs的大量合成。EDTA、DTPA、柠檬酸、苹果酸和草酸的适量供应可不同程度减轻或消除 Cd的生物毒性 ,其强弱顺序为 EDTA >DTPA 柠檬酸 >苹果酸≈草酸。与此同时 ,小麦根系内 PCs的诱导量也有明显下降 ,与 Cd的生物毒性保持一定的线性关系 ,且在EDTA、DTPA和柠檬酸供应下尤为显著。表明 PCs可以作为一项敏感的生化指标 (biochem ical indicator)用来评价和预测环境中 Cd的污染 ,并有望成为重金属生物有效性评价系统中一种新的补充方法     

可食植物中砷赋存形态研究进展

砷是环境中普遍存在的一种化学元素,近年来日益严重的砷污染问题在世界范围内受到高度重视,我国目前已经成为世界卫生组织(WHO)列出的砷污染最严重的国家和地区之一.经口摄入是外界砷进入人体并累积产生生物毒性的主要途径.可食植物是人类饮食结构中不可缺少的部分,食品总砷含量并不能完全决定其毒性大小,砷的赋存形态与其生物毒性密切相关,无机砷已被确认为致癌物质.本文主要综述了不同种类可食植物中砷形态的分析方法,以及砷的主要赋存形态及其生物毒性.     

镧系元素对海水小球藻的毒性效应

用评价化学品对藻类毒性的标准实验方法,研究了12种镧系元素对小球藻生长的抑制情况。结果表明,12种镧系元素抑制小球藻生长的96h半效应浓度(96h EC50 )均为2 9 0 0±0 5 0 μmol·L-1。对各剂量反应方程进行X2 检验,结果表明,符合精度要求,计算出的96h EC50 真实可靠。镧系元素对海水小球藻的生物毒性是相同的,此结果对探明镧系元素对藻类的生态毒理效应具有重要意义。     

中国樟科非粮生物柴油能源植物资源的初步评价与筛选

通过调查我国现有樟科油脂植物资源,本研究对74份(9属47种)樟科油脂植物样品的含油率、脂肪酸甲酯组成、碘值及其油酸甲酯的理化性质进行了分析,并根据非粮生物柴油能源植物的评价标准,初步筛选出了19份(5属18种)具有开发利用价值的樟科非粮生物柴油能源植物,为樟科油脂植物资源的评价与筛选、深度开发与综合利用等提供参考依据。     

新型战伤急救止血剂体外细胞毒性研究

目的:研究新型战伤急救止血剂的体外细胞毒性,初步探讨其用于战伤急救止血时的生物安全性.方法:参照我国医疗器械生物学评价标准,选用小鼠L929细胞,应用MTT法、直接接触培养法、流式细胞检测细胞凋亡法、扫描电镜直接观察细胞生长状况等检测新型战伤急救止血剂的细胞毒性.结果:新型战伤急救止血剂细胞毒性为0-1级,符合我国医疗器械评价标准毒性分级标准,各浓度组与阴性对照组无差异,P＞0.05;L929细胞与沸石直接接触生长良好,流式细胞仪检测细胞凋亡率与阴性对照组无差异;扫描电镜观察在沸石表面生长良好.结论:复合新型战伤急救止血剂细胞相容性良好,符合我国医疗器械安全性评价标准,是一种安全、高效、多功能的战伤止血剂.     

以大肠杆菌（E.coli）为指示菌定量评价废水综合毒性

以E.coli为指示菌，采用琼脂扩散法，适于评价富含金属的工业废水毒性。作为一种生物监测方法，它可以反映多种污染物对生物体的综合毒性结果，并可节约理化监测分析的大量人力物力，且经济简便。特别是通过建立回归方程将生物毒性与废水排放标准联合起来。根据生物毒性可计算出废水综合毒性相当排放标准的倍数，进而可对废水毒性作出定量的评价，解决了目前各种生物监测方法缺乏统一可比的评价标准或尚无公认的评价标准，以致在废水实际监测中难于推广应用的问题，使生物监测可以应用于废水实际监测工作中去，并成为环境管理工作的依据。     

海南省非粮生物柴油能源植物的调查、化学组分的测定及筛选研究

为研究海南省现有非粮生物柴油能源植物的资源特点、资源量和分布情况,对海南省现有资源进行了调查。采集样品的含油部位采用索氏提取法测定其含油量,并用碱催化法进行脂肪酸甲酯化。运用相关计算公式和＂DPS数据处理系统＂对各组分进行数据计算与分析,在第一年度数据基础上,按照生物柴油能源植物初步评价标准,筛选出非粮生物柴油能源植物共计30科、47属、59种（含2变种）,其中,罗志藤（Stixis suaveolens）和海南崖豆藤（Millettia pachyloba）是按此评价标准筛选新增加的种。分析了海南省非粮生物柴油能源植物的资源及其分布特点,对其发展潜力、保护和利用提出了建议。     

转基因植物的食品安全性问题及评价策略

转基因植物经历了20年的快速发展,已经成为21世纪农业的重要支柱之一。转基因植物从诞生以来,其食用安全性一直是科学界、政府和广大消费者关心的焦点问题。各类转基因安全事件层出不穷,严重影响着转基因产业的发展。本文从营养、毒性、过敏性、抗生素抗性、非期望效应等五个方面系统总结了转基因植物食用安全的问题,详细介绍了转基因植物食用安全评价的六大原则以及国际与国内对转基因植物食用安全性评价的内容,最后介绍了我国的转基因植物安全管理体系。以期使读者对转基因植物食用安全问题有一个系统全面的了解。     

Combination ecotoxicity and testing of common chemical discharges to sewer using the<Emphasis Type="Italic"> Vibrio fischeri</Emphasis> luminescence bioassay

In order to investigate possible synergistic or antagonistic (more or less than additive) toxicity effects, mixtures of chemicals were tested in water using a microbial bioassay. Ten toxicants (3,4-dichloroaniline, 3,5-dichlorophenol, cadmium, chromium, copper, Lindane, linear alkylbenzene sulphonate, pentachlorophenol, toluene, zinc) were chosen on the basis of their common occurrence in industrial effluents within local waste water treatment plants. These toxicants also cover a wide range of modes of toxic action, namely, polar and non-polar narcosis, membrane disruption, respiratory disruption, uncouplers of oxidative phosphorylation, biochemical disruption and enzyme inhibition. Efficient screening for possible combination toxicity between toxicants involved testing the chemicals both singly and in triplet combinations. The triplets were based on four replicates of a balanced incomplete block design (BIB). A standardised Vibrio fischeri rapid toxicity bioluminescence assay was used. The combinations tested showed that only one mixture was found to be significantly more toxic than expected from the pure single-toxicant results. Two triplets were significantly less toxic. Further tests on the more toxic triplet showed that the effect was due to only one of the 45 pairs originally screened. It is concluded that synergistic effects in combinations of toxicants are rather rare in bioluminescence systems utilising common effluents discharged to sewer. Electronic Publication     

菲、芘、1,2,4-三氯苯对土壤高等植物根伸长抑制的生态毒性效应

测定了草甸棕壤条件下,菲、芘、１,２,４—三氮苯对高等植物（小麦、白菜、西红柿）根伸长抑制串以及复合污染毒性效应。结果表明,菲、芘、１,２,４—三氮苯浓度与植物根伸长抑制串呈显著线性或对数相关（ｐ＝０．０５）。３种化学品对植物根伸长抑制的强弱顺序为１,２,４—三氮苯＞菲＞芘。这与３种化学品的水中溶解度大小显著相关。小麦是３种供试植物中对有机污染物最敏感植物。菲、芘、１,２,４—三氮苯复合污染主表现为协同作用。     

Activation of the heat shock response in plants by chlorophenols: transgenic Physcomitrella patens as a sensitive biosensor for organic pollutants

The ability to detect early molecular responses to various chemicals is central to the understanding of biological impact of pollutants in a context of varying environmental cues. To monitor stress responses in a model plant, we used transgenic moss Physcomitrella patens expressing the beta-glucuronidase reporter (GUS) under the control of the stress-inducible promoter hsp17.3B. Following exposure to pollutants from the dye and paper industry, GUS activity was measured by monitoring a fluorescent product. Chlorophenols, heavy metals and sulphonated anthraquinones were found to specifically activate the hsp17.3B promoter (within hours) in correlation with long-term toxicity effects (within days). At mildly elevated physiological temperatures, the chemical activation of this promoter was strongly amplified, which considerably increased the sensitivity of the bioassay. Together with the activation of hsp17.3B promoter, chlorophenols induced endogenous chaperones that transiently protected a recombinant thermolabile luciferase (LUC) from severe heat denaturation. This sensitive bioassay provides an early warning molecular sensor to industrial pollutants under varying environments, in anticipation to long-term toxic effects in plants. Because of the strong cross-talk between abiotic and chemical stresses that we find, this P. patens line is more likely to serve as a direct toxicity bioassay for pollutants combined with environmental cues, than as an indicator of absolute toxicity thresholds for various pollutants. It is also a powerful tool to study the role of heat shock proteins (HSPs) in plants exposed to combined chemical and environmental stresses.     

Chelate-Enhanced Phytoremediation of Soils Polluted with Heavy Metals

In general, hyperaccumulators are low biomass, slow-growing plants. High biomass non-hyperaccumulator plants by themselves are not a valid alternative for phytoextraction as they also have many limitations, such as small root uptake and little root-to-shoot translocation. In this context, chemically-induced phytoextraction (based on the fact that the application of certain chemicals, mostly chelating agents, to the soil significantly enhances metal accumulation by plants) has been proposed as an alternative for the cleaning up of metal polluted soils. But chelate-induced phytoextraction increases the risk of adverse environmental effects due to metal mobilization during extended periods of time. In order to minimize the phytotoxicity and environmental problems associated with the use of chelating agents, nowadays, research is being carried out on the gradual application of small doses of the chelating agent during the growth period. However, EDTA utilization in the future will most likely be limited to ex situconditions where control of the leachates can be achieved. There are other mobilizing agents which are much less harmful to the environment such as citric acid, NTA, and particularly EDDS. Research should also be aimed towards more innovative agronomic practices. Environmentally safe methods of chelate-induced phytoextraction must be developed before steps towards further development and commercialization of this remediation technology are taken. Most importantly, more applied projects in this field are needed to clarify the real potential and risks of this technology.     

How many high production chemicals are rodent carcinogens? Why should we care? What do we need to do about it?

High production volume (HPV) chemicals are produced in or imported to the US in amounts greater than 1 million pounds per chemical per year. The EPA has identified thousands of HPVs. Due to their abundance, such chemicals bring a substantial risk for human exposure, and as a result some level of adverse consequences to health are to be expected. In order to examine the potential for cancer risk associated with HPVs, this paper examines HPVs that have been tested in the National Toxicology Program's rodent cancer bioassay. The chemicals tested in the bioassay represent a small sample of the universe of environmental chemicals to which people are exposed. Unexpectedly, 60% of the 128 HPVs evaluated in the bioassay proved to be rodent carcinogens. This value compares to a predicted prevalence of only 16.5% carcinogens in a previous study. The previous study concluded that HPVs were less likely to be toxic by a variety of other test criteria as well. However, the approach involved identifying putative carcinogens using quantitative chemical structure-activity relationships (QSAR) in contrast to the direct tabulation of bioassay test results performed here. Detailed examination of bioassay results reveals that test outcomes depend heavily on route of administration as well as on dose level, sex, strain, and species used. Since most of these factors have little or no apparent relationship to chemical structure, results of this study suggest that QSAR, as well as virtually all other alternative methods, may not generally provide accurate predictions of carcinogenic potential. As we wait for efficient and effective methods for predicting carcinogens to be developed, people continue to be exposed to environmental carcinogens. Progress on regulating environmental carcinogens as well as on developing more effective test methods has been minimal since "war on cancer" began approximately 30 years ago. The present study questions whether the current strategy for dealing with environmental carcinogens will ever be successful. Close examination of rodent cancer test results seems to suggest that almost all chemicals may have carcinogenic potential in some genotypes under some exposure circumstances. If this hypothesis is correct, it would explain the general lack of progress in developing methods to differentiate carcinogens from noncarcinogens. A completely new strategy for dealing with cancer caused by exposures to environmental chemicals seems to be needed.     

Lithium in Environment and Potential Targets to Reduce Lithium Toxicity in Plants

Industrialization and inevitable mining have resulted in the release of some metals in environment, which have different uses on the one hand and also showed environmental toxicity. Lithium (Li) is one of them; however, its excess use in different fields or inappropriate disposal methods resulted in high Li accumulation in soil and groundwater. This subsequently is affecting our environment and more potentially our arable crop production system. In humans, Li has been extensively studied and causes numerous detrimental effects at different organ levels. Moreover, increases in Li in groundwater and food items, cases for mental disorders have been reported in different regions of the world. In plants, only a few studies have been reported about toxic effects of lithium in plants. Moreover, plant products (fruits, grains or other plant parts) could be a major source of Li toxicity in our food chain. Therefore, it is more imperative to understand how plants can be developed more tolerant to Li toxicity. In this short mini-review article, we primarily highlighted and speculated Li uptake, translocation and Li storage mechanism in plants. This article provides considerable information for breeders or environmentalist in identifying and developing Li hyperaccumulators plants and environment management.

     

Hazards from chemicals: scientific questions and conflicts of interest.

All substances are toxic when the dose is large enough. In order to regulate the use of chemicals, we need to measure the level at which toxic effects are found. Epidemiological evidence suggests that present levels of chemical use do not lead to widespread harmful contamination of the human environment. For chemicals, most of the problems of toxicity are found in the workplace, while the population at large gets most of its toxic effects from voluntary exposure to substances such as tobacco smoke and ethanol. The prevention and control of toxic effects depends on a series of steps. This begins with measurement of toxicity in model systems, such as laboratory animals, and the estimation of the likely exposure of workers or consumers. Reliable extrapolation of information gathered from animals to the diverse and biochemically differing human population depends on understanding mechanisms of toxic effects. The toxic effect and mechanisms of action of substances such as carbon tetrachloride or paracetamol have been extensively investigated, and our ability to predict toxicity or develop antidotes to poisoning has had some success, but epidemiology is still an essential part of assessment of toxic effects of new chemicals. The example of phenobarbitone shows how animal experiments may well lead to conclusions which do not apply to man. After measurement of toxicity and assessment of likely hazards in use comes the final evaluation of the use of a chemical. This depends not only on its toxicity, but also on its usefulness. The direct effects on health may be small in comparison with the indirect advantageous effects which a useful substance such as vinyl chloride may bring. The assessment of risks and benefits of new chemicals can be partly removed from a political style of discourse, but the evaluation of the relative weight to be attached to these risks and benefits is inescapably political. The scientific contribution must be to allow the debate to take place in the light of maximum clarity of information about the consequences of use of chemicals.     

SOIL-PLANT PHYTOTOXICITY AND ITS POSSIBLE SIGNIFICANCE IN PATTERNING OF HERBACEOUS VEGETATION IN A BOTTOMLAND FOREST

Plant growth inhibitors, which are known to exert synergistic effects on herbaceous vegetation, were isolated and quantified from the soils under hackberry trees. Ferulic, caffeic, and p-coumaric acids were isolated from the soils under hackberry trees collected in January, April, and September from 0–15 and 15–30 cm soil depths. Seed germination bioassay indicated considerably higher phytotoxicity levels of individual plant growth inhibitors in January and April soils, and this toxicity level was more drastic when inhibitors were applied accumulatively. Individual phytotoxins extracted from soil in September were not very inhibitory to seed germination of selected test species; however, accumulative effects were still allelopathic to seed germination. Toxicity levels of individual compounds may reduce or disappear in a given time, but the combined action of these chemicals would still be toxic in croplands or in natural communities. Ecological implications of allelopathy in terms of soil-plant interaction are discussed.     

Assessing the Risk of Herbicides to Terrestrial Non-Target Plants Using Higher-Tier Studies

Risk assessment for non-target plants is based on single species phytotoxicity tests. This approach may not reflect relevant ecological processes in terrestrial ecosystems. The current risk assessment scheme is based on endpoints measured at the species level and the assessment of ecological effects relies on the extrapolation from one species to another or from a single species to a community. This extrapolation contains many uncertainties that may be reduced by adopting more realistic testing approaches. However, currently higher-tier plant studies are not obligatory in herbicide risk assessment. We reviewed the published literature and found that potential higher-tier approaches for terrestrial non-target plants are extremely limited. Sixteen studies were found that assessed the effects of herbicides on non-target plants by performing microcosms, mesocosms, or field studies. These studies showed that microcosms might provide useful data and help to reduce uncertainties associated with single-species tests. However, due to the limited number of available studies, much work is required to develop appropriate testing methods for regulatory processes. In addition, field experiments are necessary to establish baseline knowledge concerning the effects of herbicides on natural plant communities and to compare data generated in tiered testing approaches with data obtained from natural systems.     

Genetics,novel weapons and rhizospheric microcosmal signaling in the invasion of Phragmites australis

Chemical communication and perception strategies between plants are highly sophisticated but are only partly understood. Among the different interactions, the suppressive interaction of a class of chemicals released by one plant through root exudates against the neighbouring plants (allelopathy) have been implicated in the invasiveness of many exotic weedy species. Phragmites australis (common reed) is one of the dominant colonizers of the North American wetland marshes and exhibits invasive behavior by virtually replacing the entire native vegetation in its niche. Recently, by adopting a systematic bioassay driven approach we elucidated the role of root derived allelopathy as one of the important mechanisms by which P. australis exerts its invasive behavior. Additionally, our recent preliminary data indicates the involvement of rhizobacterial signaling in the invasive success of P. australis. A better understanding of biochemical weaponry used by P. australis will aid scientists and technologists in addressing the impact of root secretions in invasiveness of weedy species and thus promote a more informed environmental stewardship.Key words: Phragmites australis, roots, phytotoxicity, reactive oxygen species, microtubules, microcosm