Antimutagenicity of polyphenol-rich fractions from sorghum bicolor grain

Polyphenols extracted from a bird-resistant sorghum (Sorghum bicolor (L) Moench) grain cultivar SSK30 were separated into three crude fractions: non-tannin polyphenols with small M_r (F₁); proanthocyanidins with M_r values between 2000 and 10000 (F₂); and proanthocyanidins with much larger M_r values of around 10000-50000 (F₃). Each fraction was tested for mutagenicity using mutants of Salmonella typhimurium (the Ames test) or the somatic mutation and recombination test (SMART) employing Drosophilu melanogaster. None of the fractions was positive with either test. On the other hand the crude polyphenols all acted as antimutagens when coincubated with mutants of S typhimurium and standard mutagens (sodium azide, daunomycin and 2-aminofluorene). The order of antimutagenicity was F₃> F₂> F₁, a decrease with decreasing M_r. It is possible that a different mechanism of polyphenol antimutagenicity occurs against the mutagen sodium azide when compared with the mutagens daunomycin and 2-aminofluorene.     

一种微生物絮凝剂急性毒性和诱变毒性作用的研究

目的研究一种微生物絮凝剂受试物的急性毒性和诱变毒性作用。方法分别对微生物絮凝剂进行了小鼠急性经口毒性试验、Ames试验、小鼠骨髓嗜多染红细胞微核试验。结果该微生物絮凝剂的小鼠急性经口毒性试验LD_(50)≥5000 mg/(kg BW);Ames试验中,各剂量组回复突变菌落数均未见明显增加,亦无剂量-反应关系;小鼠骨髓嗜多染红细胞微核试验中,微生物絮凝剂各剂量组微核细胞率与阴性对照组比较差异无显著性。结论该微生物絮凝剂对昆明种小鼠的急性经口毒性属实际无毒,在Ames试验中未呈现致突变作用,未见诱导小鼠骨髓嗜多染红细胞微核形成的能力。     

用TK基因突变试验评价丙烯酰胺的致突变性

用小鼠淋巴瘤细胞TK基因突变试验对丙烯酰胺的致突变性进行了研究。实验设0.10、0.25、0.50、0.75mg/ml4个剂量组和阴性、阳性对照组。结果发现,随着丙烯酰胺剂量的增加,细胞相对悬浮增长率下降,tk位点的突变频率显著增加,0.5、0.75mg/ml两剂量组的突变频率与阴性对照组相比有显著性差异,并且有剂量效应关系,表明丙烯酰胺有明显的细胞毒性,并可诱发tk位点的突变。     

东紫苏致突变作用的研究

目的研究东紫苏是否具有致突变作用。方法采用平板掺入法Ames试验,设每皿5000、1000、200、40、8μg剂量组,同时设阴性、阳性对照组,观察每皿回变菌落数。微核及精子畸形试验设5000、2500、1250 mg/kg·BW 3个剂量组、阴性对照组及阳性对照组。微核试验采用30 h、2次给受试物法,检测骨髓嗜多染红细胞微核率。精子畸形试验于首次染毒后第35 d处死动物,观察精子畸形率。结果与阳性对照组比较,东紫苏各剂量组在Ames试验中未呈现致突变性,骨髓细胞微核试验及小鼠精子畸变试验结果均为阴性,差异均无统计学意义(P0.05)。结论在本实验条件和剂量范围内,未发现东紫苏有致突变性作用。     

用rpsL基因突变实验评价丙烯酰胺致突变性的方法初探

采用rpsL基因突变实验对丙烯酰胺的致突变性进行了初步研究。实验设0.05、0.10、0.25、0.50、1.00 mg/mL 5个丙烯酰胺的剂量组和阴性、阳性对照组。结果发现,丙烯酰胺剂量组的突变频率与阴性对照组相比均有显著差异,并且有剂量效应关系,表明丙烯酰胺可诱发rpsL位点的突变。由于rpsL突变实验自发突变背景水平低、灵敏度高,因此rpsL突变实验有望成为食品和医药领域中致癌物快速检测的有效工具。     

4种黄曲霉毒素B1酶联免疫试剂盒 与液相法检测结果比较

目的 综合评价4 种不同厂家的黄曲霉毒素B1试剂盒。方法 选择几种食品基质(婴幼儿米粉、花生酱、酱油), 分别用R-Biopharm, Romer, Helica和华安麦科的黄曲霉毒素B1试剂盒检测, 将测定结果与液相色谱法测得结果进行比对。结果 通过与液相色谱法测得结果比较, 华安麦科试剂盒只适合检测婴幼儿米粉样品。Helica和R-Biopharm试剂盒能检测多种基质, 而Helica试剂盒检测结果与液相相符度低, R-Biopharm试剂盒检测米粉时, 本底较高。Romer试剂盒适用于花生酱和酱油样品。结论 为了得到最佳的检测结果, 针对不同的样品基质, 应选择合适的试剂盒。当用酶联法检测出阳性样品时, 需用液相色谱法确认。     

胶体金免疫层析法检测酱油中黄曲霉毒素B1

采用胶体金免疫层析法检测酱油中的黄曲霉毒素B1。加标的酱油样品经提取后,以胶体金免疫层析法对其进行黄曲霉毒素B1测定,并与酶联免疫吸附法进行比较。结果表明,当酱油中黄曲霉毒素含量超过国家限量标准(5μg/kg),胶体金免疫层析法检测结果为阳性,说明该方法能够满足酱油样品中黄曲霉毒素B1监控的要求。     

4种黄曲霉毒素B1酶联免疫试剂盒 与液相法检测结果比较

摘 要：目的 综合评价4 种不同厂家的黄曲霉毒素B1试剂盒。方法 选择几种食品基质（婴幼儿米粉、花生酱、酱油）,分别用R-Biopharm,Romer,Helica和华安麦科的黄曲霉毒素B1试剂盒检测,将测定结果与液相色谱法测得结果进行比对。结果 通过与液相色谱法测得结果比较,华安麦科试剂盒只适合检测婴幼儿米粉样品。Helica和R-Biopharm试剂盒能检测多种基质,而Helica试剂盒检测结果与液相相符度低,R-Biopharm试剂盒检测米粉时,本底较高。Romer试剂盒适用于花生酱和酱油样品。结论 为了得到最佳的检测结果,针对不同的样品基质,应选择合适的试剂盒。当用酶联法检测出阳性样品时,需用液相色谱法确认。     

Comparison of two Analytical Methods (ELISA and LC-MS/MS) for Determination of Aflatoxin B1 in Corn and Aflatoxin M1 in Milk

The aim of this paper is to assess the closeness of agreement between results of ELISA and LC-MS/MS methods for determination of aflatoxin B₁ in corn and aflatoxin M₁ in milk. Samples of corn (n=100) and milk (n=250) were simultaneously analyzed using ELISA and LC-MS/MS methods, after the severe drought that affected Serbia in summer 2012 resulting in occurrence of aflatoxin B1 in corn and aflatoxin M₁ in milk. Regression analysis showed higher level of agreement between aflatoxin B₁ samples (R²=0.994), compared to aflatoxin M₁ samples (R²=0.920). However, both techniques were satisfactory in meeting the requirements for official control purposes.     

近红外光谱技术快速无损检测轻度霉变玉米

目的 应用近红外光谱(near infrared spectroscopy,NIRS)技术对轻度霉变玉米中黄曲霉毒素进行快速无损检测。方法 本研究选取轻度霉变的玉米样本作为实验材料,以黄曲霉毒素B1 (aflatoxin B1,AFB1)的含量作为检测指标,利用NIRS图像采集系统收集了153个样本图像,采用了多元散射校正、标准正态变换及移动平均平滑(moving average smoothing,MAS)三种预处理方法对样本的原始NIRS数据(raw near-infrared spectral data,RNSD)进行了预处理。并采用反向传播神经网络(backpropagation neural network,BPNN)、极限学习机和支持向量机对处理后的光谱数据与AFB1含量数据进行建模分析,评估了预处理方法对模型性能的影响;并通过连续投影算法(stepwise projection algorithm,SPA)对预处理数据进行特征光谱选取后代入模型进行综合比较。结果 最佳光谱预处理方法为MAS,通过SPA选取出10个特征光谱,使用BPNN模型时预测结果最佳,模型预测集的决定系数可达到0.933,相对预测偏差为3.922,该模型具有良好的性能和可靠性。结论 利用NIRS技术测定轻度霉变玉米中的AFB1含量具备可行性,本研究成果为NIRS在鉴别其他农产品方面的应用提供了重要的参考依据。     

彝良小草坝天麻急性毒性和诱变毒性作用的研究

目的研究彝良小草坝天麻的急性毒性和诱变毒性作用。方法通过小鼠急性经口毒性实验、Ames实验、小鼠骨髓细胞微核实验、小鼠精子畸形实验,测定其急性毒性和遗传毒性作用。结果小鼠急性经口毒性实验LD_(50)10000 mg/kg·BW。Ames实验中,各剂量组回复突变菌落数均未见明显增加(P0.05),亦无剂量-反应关系。小鼠骨髓细胞微核实验中,各剂量组微核细胞率与阴性对照组比较差异无显著性(P0.05)。小鼠精子畸变实验中,各剂量组精子畸变率与阴性对照组比较差异无显著性(P0.05)。结论该彝良小草坝天麻对昆明种小鼠属实际无毒,在Ames实验中未呈现致突变作用,未见诱导小鼠骨髓细胞微核形成的能力,未见致小鼠精子畸变的能力。     

薏苡仁油致突变性实验研究

按照《保健食品检验与评价技术规范》,采用Ames试验、小鼠骨髓细胞微核试验和小鼠精子畸形试验研究薏苡仁油的致突变性。结果表明:Ames试验、小鼠骨髓细胞微核试验和小鼠精子畸形试验结果均为阴性。因此,在本试验条件下,薏苡仁油未显示有致突变性。     

Evaluation of atoxigenic isolates of Aspergillus flavus as potential biocontrol agents for aflatoxin in maize

Aflatoxin contamination resulting from maize infection by Aspergillus flavus is both an economic and a public health concern. Therefore, strategies for controlling aflatoxin contamination in maize are being investigated. The abilities of eleven naturally occurring atoxigenic isolates in Nigeria to reduce aflatoxin contamination in maize were evaluated in grain competition experiments and in field studies during the 2005 and 2006 growing seasons. Treatments consisted of inoculation of either grains in vials or ears at mid-silking stage in field plots, with the toxigenic isolate (La3228) or atoxigenic isolate alone and co-inoculation of each atoxigenic isolate and La3328. Aflatoxin B₁?+?B₂ concentrations were significantly (p?<?0.05) lower in the co-inoculation treatments compared with the treatment in which the aflatoxin-producing isolate La3228 was inoculated alone. Relative levels of aflatoxin B₁?+?B₂ reduction ranged from 70.1% to 99.9%. Among the atoxigenics, two isolates from Lafia, La3279 and La3303, were most effective at reducing aflatoxin B₁?+?B₂ concentrations in both laboratory and field trials. These two isolates have potential value as agents for the biocontrol of aflatoxin contamination in maize. Because these isolates are endemic to West Africa, they are both more likely than introduced isolates to be well adapted to West African environments and to meet regulatory concerns over their use throughout that region.     

响应面法优化成曲蚕豆瓣子中黄曲霉毒素B1的提取

郫县豆瓣中所用蚕豆是产自四川省和云南省的优质干蚕豆,经筛选、浸泡、接种、制曲等一系列加工后形成成曲蚕豆瓣子。采用酶联免疫吸附法(ELISA),根据Box-Behnken Design软件的设计原理,检测成曲蚕豆瓣子中黄曲霉毒素B1。探讨了甲醇浓度、料液比、超声波提取时间等因素对样品中黄曲霉毒素提取的影响,以确定检测生产过程中样品黄曲霉毒素含量的最优方案。以黄曲霉毒素含量为响应值,利用响应面分析法对提取参数进行优化。结果表明:甲醇浓度39.66%,超声波提取时间27.70min,超声波提取功率88.97%是检测成曲蚕豆瓣子中黄曲霉毒素含量的最优条件,以该优化条件检测成曲蚕豆豆瓣子中黄曲霉毒素其值达到最大,为1.47μg/kg。     

The effect of village processing techniques on the content of aflatoxins in corn and peanuts in Zambia

The effect of village processing techniques on the aflatoxin content of corn and peanut products was investigated. In 30 trials, corn kernels were dehulled (bran removal), soaked for 24 h, washed and dried before grinding into flour and boiling in water to a thick consistency (Nshima). Shelled peanuts were either dry-roasted as whole kernels or ground into peanut meal and cooked. Dehulling, following by 24-h soaking (steeping) and subsequent washing significantly (P<0·05) reduced the aflatoxin B₁ content of corn flour from 900 to 150 μg kg⁻¹, and similarly that of aflatoxin G₁ from 929 to 114 μg kg⁻¹. Preparation of Nshima did not result into a substantial reduction in aflatoxin content, neither did extension of the cooking duration of 2 h afford any further decontamination. Whereas boiling peanut meal yielded a moderate reduction in the content of aflatoxins B₁ and G₁, roasting whole peanut kernels greatly reduced (P<0·001) the concentrations of the toxins from that in raw kernels (AFB₁= 8600 μg kg⁻¹ and AFG₁=6200 μg kg⁻¹) to 1300 and 1200 μg kg⁻¹, respectively. These results indicate that specific processing techniques carried out in Zambian villages are effective in reducing aflatoxin carry-over into edible fractions, while others are not. © 1998 SCI.