两种邻苯二甲酸酯类物质的抗雄激素作用研究

目的探讨邻苯二甲酸二(2-乙基)己酯(DEHP)和邻苯二甲酸二丁酯(DBP)的抗雄激素作用。方法参照OECD Hershberger试验指南进行,以6周龄雄性去势SD大鼠为实验动物,随机分为16组(7只/组),分别以DEHP和DBP为受试物,DEHP剂量分别为35、70、150、250、500、1 000 mg/kg BW,DBP剂量分别为70、150、250、500、750、1000 mg/kg BW;阴性对照组和阳性对照组分别灌胃给予玉米油和3.0 mg/kg BW氟他胺,连续10 d。灌胃前各组均皮下注射丙酸睾酮。试验结束后测定阴茎头、腹侧前列腺、精囊、肛提肌-海绵体肌、尿道球腺重量和血清中睾酮、黄体生成素水平。利用基准剂量分析软件分析雄激素依赖器官重量的剂量-反应关系。结果 250、500、1 000 mg/kg BW DEHP剂量组腹侧前列腺、肛提肌-海绵体肌、尿道球腺重量低于对照组,差异有统计学意义(P0.05);500、750、1 000mg/kg BW DBP剂量组肛提肌-海绵体肌、尿道球腺低于对照组,差异有统计学意义(P0.05),各组间血清激素水平差异无统计学意义(P0.05);基准剂量分析发现,DEHP和DBP对肛提肌-海绵体肌、尿道球腺重量影响具有剂量-反应关系,两种物质抗雄激素作用的基准剂量下限分别为150.38和276.78 mg/kg BW。结论经口摄入DEHP、DBP均会产生抗雄激素作用,肛提肌-海绵体肌、尿道球腺重量变化是较敏感指标。     

A system of defined (Sensu stricto) media for daphnid (Cladocera) culture

MS is a set of defined media. It is comprised of inorganics, plus crystalline vitamin B₁₂ and, usually, a glycylglycine buffer, which are dissolved in distilled-deionized water. Algal and animal media differ only in that algal media contain more phosphate, nitrate and silicate. MS supports the culture of a variety of daphnids. In particular long term (50 + generations), healthy (300 + progeny per mother in 15 + regularly-spaced broods), cultures of Daphnia pulex (de Geer) and D. magna (Straus) have been maintained. Undefined organics (fish chow, yeast, liver extracts, complex vitamin or protein mixtures) and the uncertain array of inorganic contaminants which they carry are avoided by controlling two trophic levels. Because it can be precisely reproduced in any reasonably equipped laboratory, MS holds promise as a basis for genuinely repeatable daphnid chronic bioassay yielding reproducible results.     

Synthesis and field bioassay of some analogs of sex pheromone of citrus mealybug,Planococcus citri (Risso)

A series of structural analogs of (s+)-cis-(1R)-3-isopropenyl-2,2-dimethylcyclobutanemethanol acetate, sex pheromone of the citrus mealybug,Planococcus citri (Risso), was synthesized. The analogs were tested in a field bioassay in order to determine the structure-activity relationships of the pheromone. All changes in structure reduced the activity of the test compounds, to various degrees. The most active analog tested was the homolog (+)-cis-(1R)-3-isopropenyl-2,2-dimethylcyclobutaneethanol acetate (IV), whose activity, at a higher dosage, was comparable to that of the pheromone. The alcohol (+)-cis-(1R)-3-isopropenyl-2,2-dimethylcyclobutanemethanol was tested in mixtures with the pheromone and found to be neither an inhibitor nor a Synergist. The results show that all functional groups of the pheromone molecule are essential for optimal biological activity.Homoptera: Coccoidea: Pseudococcidae.Contribution from the Agricultural Research Organization (ARO), The Volcani Center, Bet Dagan, Israel, No. 1667-E, 1986 series.Levi Eshkol Postdoctoral Fellow, 1984–1986.     

食物铁生物利用率评价方法现状

目前食物铁生物利用率的评估方法分为动物实验法、体外测量法、数学模型法与人体试验法四种。本文对这四种评价方法的应用现状进行了详细的介绍,同时还分析、总结了各种评价方法的优劣。     

A two-species marine algal bioassay for detecting aquatic toxicity of chemical pollutants

A simple, rapid and sensitive two-species marine algal bioassay for determining the toxicity of chemical pollutants was developed. The bioassay employs the marine diatoms Phaeodactylum tricornutum (clone Phaeo) and Cyclotella cryptica (clone 03A), which were selected after screening 40 clones of 32 species for an optimum pair of organisms. These algae are easily grown in the laboratory, and the cells can be differentiated and counted with an electronic particle counter. Alteration of species ratio and/or total biomass were used to determine toxicity. Polychlorinated biphenyls (PCB, Aroclor 1254) at 10 parts per thousand million (10⁹; ptm) significantly altered species ratio in favor of Phaeo, and 10 ptm of DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) and 20 ptm of dieldrin produced a significant species alteration opposite to that produced by PCB.     

Toxicity profile of commercially produced indigenous banana beer

Mycotoxins, together with endotoxins, represent important classes of naturally occurring contaminants in food products, posing significant health risks to consumers. The aim of this study is to investigate the occurrence of both Fusarium mycotoxins and endotoxins in commercially produced traditional banana beer. Two brands of commercially produced traditional banana beer were collected from a local retail market in Kigali, Rwanda. Beer samples were analysed for the presence of deoxynivalenol (DON), fumonisin B₁ and zearalenone (ZEA), using an enzyme-linked immuno-sorbent assay (ELISA) method. The quantification of bacterial endotoxin using Limulus amoeboecyte lysate (LAL) assay was also conducted. The contamination levels were 20 and 6.7?µg?kg^?1 for DON; 34 and 31.3?µg?kg^?1 for FB₁; 0.66 and 2.2?µg?kg^?1 for ZEA in brands A and B of the beers, respectively. Results indicate that the levels of Fusarium toxins and bacterial endotoxin reported in this study did not pose adverse human health effects as a result of drinking/consuming banana beer. However, exposure to low/sub-threshold doses or non-toxic levels of endotoxins magnifies the toxic effect of xenobiotic agents (e.g. fungal toxins) on liver and other target organs. Considering Fusarium toxins and/or endotoxin contamination levels in other agricultural commodities intended for human consumption, health risks might be high and the condition is aggravated when beer is contaminated by mixtures of the mycotoxins, as indicated in this study.     

Action of Extracts of Apiaceae on Feeding Behavior and Neurophysiology of the Field Slug Deroceras reticulatum

A systematic examination was made of the plant family Apiaceae (Umbelliferae) in which extracts of 33 species, representing 32 genera, were screened for antifeedant activity against the field slug Deroceras reticulatum by using an electrophysiological recording assay. In this assay, the olfactory sensory epithelium of the posterior tentacle of the slug was exposed to volatile components of the plant extracts presented in an airstream, and any subsequent activity of the olfactory nerve was recorded. Extracts of 22 species elicited a range of nervous activity in the preparation. A feeding bioassay was used to measure any change in consumption when extracts were added to a standard food. Statistical analysis of data obtained from both electrophysiological traces and the feeding bioassays identified extracts of Petroselinum crispum, Conium maculatum, and Coriandrum sativum as being the most neuroactive as well as the most antifeedant.     

Allelopathic Potential of Aquatic Plants Associated with Wild Rice (Zizania palustris): I. Bioassay with Plant and Lake Sediment Samples

The allelopathic potential of eight aquatic plants associated with wild rice was investigated using lettuce and wild rice seedling bioassays. Rhizome aqueous extracts of Scirpus acutus, Potamogeton natans, Nymphaea odorata, Nuphar variegatum; shoot extract of Eleocharis smallii; whole plant extract of Myriophyllum verticillatum; and leaf extract of P. natans significantly reduced the root length of lettuce and wild rice seedlings. The lettuce seedling bioassay was more sensitive than the wild rice bioassay. Shoot growth was less affected than the root growth. Water extract of sediments associated with the aquatic plants had little growth inhibitory effect on wild rice. Our study did not yield any conclusive evidence that the wild rice-associated aquatic plants have allelopathic effects on wild rice. We emphasize the use of target species as a bioassay material in allelopathic studies. Further investigation on allelopathic effects of lake sediments associated with the neighboring plants of wild rice is necessary to evaluate their ecological significance.     

Behavioral Responses of Adult <Emphasis Type="Italic">Sitophilus granarius</Emphasis> to Individual Cereal Volatiles

The antennae of Sitophilus granarius (L.) (Coleoptera: Curculionidae) adults detect a wide variety of compounds in the odor blend of various cereal grains (Germinara et al., Tec. Molit., 53:27–34, 2002). In the present study, we looked at the behavioral responses of the granary weevil to 20 of these individual volatiles (aliphatic alcohols, aldehydes, ketones, and aromatics) in a two-choice pitfall olfactometer, using the aggregation pheromone and propionic acid as the attractant and repellent controls, respectively. Five doses, ranging from 1 μg to 1 mg, of each compound were tested. At least one concentration of eight compounds attracted beetles but required doses 1,000- to 5,000-fold higher than the concentration of aggregation pheromone to elicit a response. Three compounds, while attractive at lower concentrations, acted as repellents at higher doses. Twelve compounds were repellent at concentrations similar to the quantity of propionic acid that significantly repelled beetles. The data show that granary weevil adults have the ability to respond behaviorally to a wide range of cereal volatiles and that responses may change as a function of concentration. The results suggest that host finding behavior of weevils will depend on the balance of positive and negative volatile stimuli from grain as the relative concentrations of volatiles may change during storage. An understanding of how the weevils respond to such changes could be useful for the development of effective integrated pest management strategies.     

Physiological Assessment and Path Coefficient Analysis to Improve Evaluation of Alfalfa Autotoxicity

Reseeding of alfalfa is affected until autotoxic chemicals break down or are dispersed, often requiring a year or more. Bioassays of seed germination and early seedling growth, on agar medium in petri dishes, were conducted to evaluate autotoxic responses of 20 alfalfa germplasms to water-soluble extracts of alfalfa leaf tissue. Root length, 120 hr after placing imbibed seed on agar, was more sensitive to the autotoxin(s) than was hypocotyl length, germination speed, and final germination percentage. Path coefficient analyses showed variation in root length had 7–17 times more effect than variation in hypocotyl length in determining autotoxic effects on total seedling length. Although variations in seed size and germination rate were negatively associated (P < 0.05) with final root length, the autotoxin had little effect on these factors relative to that on root length. Germplasms in the control differed (P < 0.05) in root length, requiring tolerance to be evaluated as percent of control. Germplasms, as percent of control, differed significantly (P<0.05) at extract concentrations of 1.0 and 4.0 g l^–1, but the range and LSD were more favorable for selection at 1.0 g l^–1. Root length is appropriate for genetic assessments of tolerance to the autotoxin when expressed as percent of control.