泊洛沙姆（Poloxamer）在脂溶性化感物质生物检测中的应用

在脂溶性化感物质的生物检测中,常规方法是使用有机溶剂对化感物质进行助溶,此法本身会对受体植物产生为害,并且不能准确定量.本研究结合药剂学理论,将动物和细胞实验中常用的增溶剂泊洛沙姆(F-68)应用于脂溶性化感物质的生物检测,用泊洛沙姆对香草醛和阿魏酸两种化感物质进行增溶,以乙醇助溶为对照,比较两种方法的化感物质活性.结果表明,化感物质用泊洛沙姆增溶后,形成的溶液是一个稳定的体系,试验过程中浓度不会发生变化,可准确定量考察化感物质的活性,同时泊洛沙姆对受体植物不产生影响.乙醇助溶处理中,或由于乙醇不易完全挥发,因乙醇的存在而对受体植物产生影响,表现为化感物质活性的加强;或随乙醇的挥发,化感物质以晶体析出,表现为化感物质活性的减弱,不能准确定量考察化感物质的活性.     

无籽刺梨多糖纳米粒制备工艺优化及表征

目的:采用双乳化溶剂蒸发法,优化无籽刺梨多糖纳米粒制备工艺,并对其进行表征.方法:采用响应面法以内水相W1和有机相O的比例、初级乳PE和外水相W2的比例以及泊洛沙姆P188的浓度为自变量,纳米粒的包封率为响应值,对制备工艺进行优化.结果:最佳制备工艺为W1和O的比例为1:8,PE和W2的比例为1:7,泊洛沙姆P188的...     

巴茅草水浸提液对3种作物种子萌发及幼苗生长的化感作用

本文以发芽率、发芽速度指数、发芽指数、根长、茎长和生物量为种子萌发和幼苗生长参数,研究不同生长时期巴茅草叶片和茎秆水浸提液对白菜、生菜、水稻的化感作用。结果表明: 巴茅草叶水浸提液化感作用强于茎秆水浸提液,叶水浸提液处理后受体植物的发芽指数和生物量均显著低于茎水浸提液。枯萎期巴茅草的化感作用强于生长旺盛期。不同浓度巴茅草叶水浸提液对3种作物的化感作用存在明显的量效关系,浸提液浓度越高,巴茅草的化感抑制作用越强。巴茅草叶水浸提液对白菜和生菜各萌发指标100%抑制的浓度分别为0.075和0.10 g·mL^-1;而0.10 g·mL^-1巴茅草叶水浸提液对水稻发芽率、发芽速度指数、发芽指数的抑制率分别为13.8%、27.2%、19.3%。巴茅草叶水浸提液对白菜和生菜各生长指标100%抑制的浓度分别为0.05和0.10 g·mL^-1;而0.10 g·mL^-1巴茅草叶水浸提液对水稻根长、茎长、生物量的抑制率分别为64.6%、92.9%、21.8%。结合种子萌发和幼苗生长的综合化感指数,3种供试作物对巴茅草化感作用的敏感程度为白菜>生菜>水稻。     

钛- 载药纳米复合材料的组装及其性质的研究

目的:构建一种能结合钛表面的载药纳米粒及钛-载药纳米复合材料的组装和性质研究。方法:(1)多巴胺修饰的非离子表面活性剂多巴胺-泊洛沙姆188(Dop-Poloxamer188)的合成和检测;(2)Dop-Poloxamer188作为表面活性剂、PLGA作为油相基质,制备纳米粒及纳米粒载药和表征;(3)钛片的预处理及钛片与修饰后的纳米粒的结合;(4)纳米粒修饰后的钛表面的表征。结果:新合成的Dop-Poloxamer188在285 nm左右有紫外吸收峰,说明多巴胺成功的修饰在Poloxamer188的两端;Dop-Poloxamer188能和PLGA制备出很好的纳米粒,平均粒径在110 nm左右,PDI小于0.1;多巴胺修饰的纳米粒与钛片通过简单的浸渍过程结合后,通过水接触角、场发射扫面电镜(Fe-SEM)、荧光显微镜、X射线光电子能谱(XPS)等仪器检测都显示多巴胺修饰的纳米粒成功且牢固的修饰在钛片表面。结论:成功达到钛表面的载药纳米粒修饰的目的,为钛种植体的载药系统提供了新的思路和方法。     

马缨丹叶片水提物与挥发油的生物活性及化学成分研究

研究了马缨丹 ( Lantana camara L.)叶片水提物和挥发油水溶液的化感作用。结果表明 ,马缨丹叶片水溶物浓度在 0 .2 5 g FW m L- 1时 ,对所有受试植物的幼苗生长均有一定的抑制作用 ,浓度降至 0 .1 0 g FWm L- 1时 ,其抑制作用显著降低 ;马缨丹叶片挥发油水溶液在浓度为 1 0 0、2 0 0、30 0 μg m L- 1时 ,对受试植物均有很强的抑制作用 ,且具有明显的浓度效应。采用 GC/MS分析了马缨丹叶片挥发油的化学成分 ,鉴定了 1 9种化感物质 ,其中α-子丁香烯和β-子丁香烯为主要物质 ,分别占挥发油含量的 1 6 .2 9%、2 2 .2 9%。     

人参皂苷对4种栽培作物早期根系发育的化感效应

人参、西洋参能通过根系分泌三萜皂苷等化感物质,严重影响后茬人参的生长,但对人参以外的植物是否具有化感效应尚不清楚.本实验研究了不同质量浓度的人参皂苷对小麦、白菜、黄瓜及绿豆4种常见栽培作物早期根系发育的影响,结果发现人参皂苷处理液(25、50和100 mg· L-1)对4种作物主根及不定根的发育影响不尽相同.随着处理质量浓度的升高,小麦、白菜、黄瓜根系活力分别比同组CK明显降低,根长、根鲜重也呈降低趋势.各浓度人参皂苷处理对黄瓜和绿豆下胚轴不定根的数量、根长、根鲜重及根系活力的影响均未达到显著水平,但二者抗氧化酶的活性都微有升高.总之,人参皂苷对4种栽培作物的主根发育均有抑制作用,尤其对小麦、黄瓜主根生长的抑制作用较强;但对黄瓜和绿豆不定根发育的影响不明显.     

表面活性剂对香石竹切花保鲜效果的研究

目的:解决香石竹采后运输和瓶插过程中花朵衰老问题.方法:研究表面活性剂对香石竹切花保鲜效果,测定瓶插期间的花枝鲜重、花朵直径、SOD活性.结果:由蔗糖25mg/L+柠檬酸200mg/L+8-HQ 200mg/L+吐温0.01%组成的保鲜剂配方,比对照能延长切花瓶插寿命11.4d.结论:在保鲜剂配方中可以使用表面活性剂(如吐温)等物质,其浓度控制在0.01%范围内.     

香草醛对杉木幼苗生长的影响

为了解杉木连栽土壤中有毒化感物质对杉木幼苗毒害作用 ,采用水培杉木幼苗方法 ,通过投加不同浓度香草醛 ,发现 1mg·kg- 1 香草醛显著抑制杉木种子胚根的伸长 (P<0 .0 5) ,只为对照的 70 % ;香草醛浓度达 1 0mg·kg- 1 时 ,叶绿素总量明显下降到对照的80 % ;超过 2 0mg·kg- 1 对杉木幼苗地径与高度生长产生明显抑制作用 ;50mg·kg- 1 以上将明显影响地上部分枝叶的正常生长发育 ,及至植株冠层的生长 ;超过 1 0 0mg·kg- 1 ,整个植株的生长受到显著抑制 .香草醛是连栽土壤中毒性较大的一种有毒化感物质 ,是杉木存活率低的重要原因之一 .     

人参皂苷对4种栽培作物早期根系发育的化感效应

人参、西洋参能通过根系分泌三萜皂苷等化感物质,严重影响后茬人参的生长,但对人参以外的植物是否具有化感效应尚不清楚。本实验研究了不同质量浓度的人参皂苷对小麦、白菜、黄瓜及绿豆4种常见栽培作物早期根系发育的影响,结果发现人参皂苷处理液（25、50和100mg·L-1）对4种作物主根及不定根的发育影响不尽相同。随着处理质量浓度的升高,小麦、白菜、黄瓜根系活力分别比同组CK明显降低,根长、根鲜重也呈降低趋势。各浓度人参皂苷处理对黄瓜和绿豆下胚轴不定根的数量、根长、根鲜重及根系活力的影响均未达到显著水平,但二者抗氧化酶的活性都微有升高。总之,人参皂苷对4种栽培作物的主根发育均有抑制作用,尤其对小麦、黄瓜主根生长的抑制作用较强;但对黄瓜和绿豆不定根发育的影响不明显。     

氯化三辛基甲胺/氯仿/正丁醇反胶束萃取地木耳多糖

采用阳离子表面活性剂氯化三辛基甲胺(TOMAC)/氯仿/正丁醇反胶束体系萃取地木耳中的多糖。分析有机溶剂氯仿与助表面活性剂正丁醇比例、TOMAC浓度、多糖粗提液浓度、促溶剂盐酸胍浓度、盐离子种类和浓度对前萃取率的影响。结果表明:向0.5 mg/m L多糖粗提液中加入10 mmol/L盐酸胍(Gu HCl)和0.06 mol/L Na Cl,与等体积25 mmol/L TOMAC/氯仿-正丁醇(V∶V=3∶1)的反胶束体系混合,地木耳多糖前萃取率为53.21%;反萃时水相中Na Cl浓度为0.14 mol/L,盐酸胍浓度浓度为0.6 mol/L,在此条件下地木耳多糖反萃取率为93.2%。     

Impact of Surfactants on Control of the Root Weevil Diaprepes abbreviatus Larvae with Steinernema riobravis

A filter paper bioassay was developed for testing the efficacy of nematodes and other agents for control of Diaprepes abbreviatus larvae. Surfactants, with and without Steinernema riobravis, were screened first in the filter paper bioassay and then in a potted citrus seedling study. The results of the two assays were in agreement on the relative merits of the compounds tested. Surfactants increased larval mortality at 4 days for the filter paper bioassay and 1 week for the potted plant bioassay. At 8 days for the filter paper bioassay and 2 weeks for the potted plant bioassay, nematodes alone were equal to treatments of nematodes plus surfactants.     

Surfactants in microbiology and biotechnology: Part 2. Application aspects

Surfactants are amphiphilic compounds which can reduce surface and interfacial tensions by accumulating at the interface of immiscible fluids and increase the solubility, mobility, bioavailability and subsequent biodegradation of hydrophobic or insoluble organic compounds. Chemically synthesized surfactants are commonly used in the petroleum, food and pharmaceutical industries as emulsifiers and wetting agents. Biosurfactants produced by some microorganisms are becoming important biotechnology products for industrial and medical applications due to their specific modes of action, low toxicity, relative ease of preparation and widespread applicability. They can be used as emulsifiers, de-emulsifiers, wetting and foaming agents, functional food ingredients and as detergents in petroleum, petrochemicals, environmental management, agrochemicals, foods and beverages, cosmetics and pharmaceuticals, and in the mining and metallurgical industries. Addition of a surfactant of chemical or biological origin accelerates or sometimes inhibits the bioremediation of pollutants. Surfactants also play an important role in enhanced oil recovery by increasing the apparent solubility of petroleum components and effectively reducing the interfacial tensions of oil and water in situ. However, the effects of surfactants on bioremediation cannot be predicted in the absence of empirical evidence because surfactants sometimes stimulate bioremediation and sometimes inhibit it. For medical applications, biosurfactants are useful as antimicrobial agents and immunomodulatory molecules. Beneficial applications of chemical surfactants and biosurfactants in various industries are discussed in this review.     

Evaluation of surfactants as solubilizing agents in microsomal metabolism reactions with lipophilic substrates

Solubilizing agents are routinely added when investigating the biotransformation of lipophilic substrates using hepatic microsomes. For highly lipophilic compounds, the concentration of solvent or surfactant necessary for dissolution can be detrimental to enzyme activity. This study evaluates the effect of 12 surfactants on microsomal metabolism and the ability of the same surfactants to improve the aqueous solubility of the pentabrominated diphenyl ether BDE-100, a lipophilic environmental contaminant previously found to be recalcitrant to in vitro metabolism. Of the surfactants investigated, Cremophor EL and Tween 80 displayed the best combination of increased BDE-100 solubility and minimal inhibition of microsomal metabolism. However, a comparison of the in vitro metabolism products of BDE-100 in the presence of the two surfactants revealed varying amounts of metabolites depending on the surfactant used.     

底物的分散和溶解对甾体微生物酶反应的影响

甾体的溶解是微生物转化反应的控制步骤。表面活性剂对憎水性物质的增溶作用是具有憎水内核胶团形成的直接结果。随表面活性剂溶液浓度的增加,胶团数目增加,甾体水溶性增强。复配型分散剂PSE－MGE应用于甾体转化体系,相对于单组分分散剂PSE而言,实现同一程度甾体水溶性增强所需的表面活性剂用量减少,对菌体生长的负面影响较小,有利于转化。超声与分散剂配合使用的效果优于分解剂单独使用的效果,且使用较强的超声声强（12.4W/cm^2）和较短的超声时间（5min）时效果最佳。     

Physiological aspects. Part 1 in a series of papers devoted to surfactants in microbiology and biotechnology

Surfactants, both chemical and biological, are amphiphilic compounds which can reduce surface and interfacial tensions by accumulating at the interface of immiscible fluids and increase the solubility, mobility, bioavailability and subsequent biodegradation of hydrophobic or insoluble organic compounds. Investigations on their impacts on microbial activity have generally been limited in scope to the most common and best characterized surfactants. Recently a number of new biosurfactants have been described and accelerated advances in molecular and cellular biology are expected to expand our insights into the diversity of structures and applications of biosurfactants. Biosurfactants play an essential natural role in the swarming motility of microorganisms and participate in cellular physiological processes of signaling and differentiation as well as in biofilm formation. Biosurfactants also exhibit natural physiological roles in increasing bioavailability of hydrophobic molecules and can complex with heavy metals, and some also possess antimicrobial activity. Chemical- and indeed bio-surfactants may also be added exogenously to microbial systems to influence behaviour and/or activity, mimicking the latter effects of biosurfactants. They have been exploited in this way, for example as antimicrobial agents in disease control and to improve degradation of chemical contaminants. Chemical surfactants can interact with microbial proteins and can be manipulated to modify enzyme conformation in a manner that alters enzyme activity, stability and/or specificity. Both chemical- and bio-surfactants are potentially toxic to specific microbes and may be exploited as antimicrobial agents against plant, animal and human microbial pathogens. Because of the widespread use of chemical surfactants, their potential impacts on microbial communities in the environment are receiving considerable attention.     

Bioactive steroids from Oryza sativa L

Rice is one of the most interesting crops in the world from both the social and the economic point of views. The monoculture practices along with the heavy use of herbicides are characteristic of modern agriculture and are inducing the appearance of tolerant and/or herbicide resistant weed biotypes. This is the case the world's main weed of rice barnyardgrass (Echinochloa crus-galli). Alternative strategies for weed suppression consist of the use of chemicals from rice due to necessity of obtaining new herbicides with new modes of action that could prevent resistance phenomena. In order to carry out a study that guides to the isolation of the most active compounds from rice, different extracts were achieved, and their activities evaluated. So, all the plant material was divided into three parts: fresh plant, dried plant, and fresh plant from Pluviotron. The aerial part was separated from roots in all cases and extracted in water, in organic solvents as well as with the Pluviotron device. The activity of the 12 extracts obtained was evaluated using a generalist bioassay, wheat etiolated coleoptiles bioassay, and a phytotoxic bioassay on barnyardgrass as target species. The bioactive extracts were fractionated and 15 compounds were isolated and identified by spectroscopic methods. Eight of these compounds were isolated for the first time in Oryza sativa. The most phytotoxic compounds on E. crus-galli were ergosterol peroxide and 7-oxo-stigmasterol. In the case of ergosterol peroxide the activity was higher than the commercial herbicide Logran. This is the first report of potential allelopathic activity of steroids on weeds based on their phytotoxicity.     

A bioassay for insect deterrent compounds found in plant and animal tissues

A general field bioassay for detecting biologically active compounds in plants and insects has been developed and tested for efficacy and sensitivity. Methanolic extracts, in sucrose solution, of 20 plant and six caterpillar species were offered to the ponerine ant Paraponera clavata and the feeding preferences observed. The bioassay resulted in the detection of nine plant and three caterpillar species with ant-deterrent extracts, and 11 plant and three caterpillar species with neutral or attractant extracts. All of the plants showing ant-deterrent characteristics which had been chemically investigated in our laboratory, or for which chemical literature was available, contained secondary metabolites of known deterrence. Both naturally occurring and artificial differences in chemical concentrations could be detected using the bioassay. The method provides a means of screening plants and insects for compounds that are insect anti-feedants or that can modify insect behaviour.     

Sensitive bioassays for determining residues of sulfonylurea herbicides in soil and their availability to crop plants

Sulfonylurea herbicides are potent inhibitors of plant growth and are extremely active against a wide spectrum of weeds. They are used at very low rates (10–50 g ai/ha) and cause rapid inhibition of root and shoot growth of young plants. Routine chemical assays for detecting low levels of these compounds are difficult and there is need to develop sensitive bioassay methods for detecting their extremely low residue levels in the soil.This paper describes a simple pot bioassay method with a self watering system using turnip (Brassica rapa) seedlings as test plants for quantitative determination of sulfonylurea herbicides. Results are presented with six of these compounds whose activity was investigated in widely differing substrates. The potential availability to plants was calculated from the dose-response curves in different substrates. The dose-response relationship has been described by a specifically developed computer model. Details are also given of a direct seeded bioassay method with controlled watering system using several test species for detection of sulfonylurea herbicides. The potential uses and practical applications of both techniques are discussed.     

表面活性剂对土壤中多环芳烃生物有效性影响的研究进展

表面活性剂能够改变多环节烃(Polycyclic aromatic hydrocarbons,PAHs）在土壤中的溶解度、吸附/解吸平衡和与土壤微生物的相互作用,从而改变PAHs的生物有效性,表面活性剂主要通过降低土壤-水之间的界面张力,增加PAHs的溶解度、促进PAHs的运输等方式来加强PAHs的生物有效性,但由于表面活性剂本身对微生物的毒害作用或无毒的表面活性剂优先作为微生物的生长基质,可能会对PAHs的生物有效性起到抑制作用,另外,表面活性剂对土壤中不同形态的PAHs生物有效性的影响不同,表面活性剂、PAHs和土壤微生物的类型浓度以及土壤的物理化学条件等都对PAHs的生物有效性有影响。     

Some chromatographic characteristics of germination stimulants in plant-derived smoke extracts

Plant-derived smoke extracts stimulate the germination of many different seeds. the present report explains steps to determine some of the chemical characteristics of the compounds concerned. Grand Rapids lettuce seeds were used as a bioassay because smoke-derived extracts overcome their light-sensitivity. The active compounds were partitioned into ethyl acetate, separated by various TLC systems and fractionated by reverse phase HPLC. They are stable surviving a series of chromatographic steps and are very active biologically. In order to ascertain their chemical properties it was necessary to use a range of dilutions after each isolation step. It would appear that similar types of compounds are present in smoke extracts derived from different plant material.