Study of the toxicological mechanism of acidified aerosols

More than 30 aerosol samples were collected from 1 place near Zaojiaban Road (downtown of Shanghai) and 1 village near Jiading country (suburb) by a stacked-filter air sampler. The coarse particulates (>2.5 μm) and the fine particulates (PM_2.5) and their unsoluble parts were analyzed by proton-induced X-ray emission. The cytotoxicity of particulates from the two places was evaluated by malondialdehyde (MDA) and thiazolyl blue (MTT) methods. The results show that the transition metal Fe, Cr, and Mn compounds from downtown are more easily soluble than those from the suburb, both in coarse and fine particulates, and the S content is much higher in particulates from downtown than that from the suburb. The cytotoxicity of the particulates from downtown is higher than that from the suburb and the cytotoxicity of acidified particulates is significantly higher than that of the controls. Because there are higher-soluble transition metal compounds that can induce free radicals in acidified particulates, the soluble transition metals may be one of the main factors for cytotoxicity.     

Improved methods of zearalenone and moniliformin preparation

Modified procedures of zearalenone and moniliformin preparation, using solid substrate (rice or corn kernels) has been developed. Preliminary purification of toxins by 1iquid-liquid partition was applied, followed by column chromatography on silicagel and charcoal. Final yield was about lg from 1kg of dry cultures of crystalline zearalenone and liophylized moniliformin o high purity.     

Formation of moniliformin by Fusarium sporotrichioides and Fusarium culmorum

Two strains of Fusarium sporotrichioides and one strain of F. culmorum were shown to produce the mycotoxin moniliformin in rice culture. Identification was by reverse-phase liquid chromatography, thin-layer chromatography, and mass spectrometry.     

Determination of moniliformin using SAX column clean-up and HPLC/DAD-detection

This work describes a method for the determination of theFusarium mycotoxin moniliformin (MON) in cereals. In addition to the optimization of the clean-up and the HPLC determination the most efficient extraction mode was investigated on natural contaminated samples. The method was validated for maize and wheat using a calibration range from 57 to 2300 μg/kg. Due to the ionic nature of the toxin the clean-up of the extracts was carried out with strong-anion-exchange columns. Moniliformin was separated by reversed phase ion-pair-chromatography (RP-Ion pair-HPLC) and detected by DAD. The validated method yielded recoveries of 76%±9% (maize) and 87%±5% (wheat) and detection limits of 39 μg/kg and 30 μg/kg, respectively. The suitability of the developed method was demonstrated on natural contaminated samples. Presented at the 25^th Mykotoxin Workshop in Giessen, Germany, May 19–21, 2003     

A study on the inhibition of rat myocardium glutathione peroxidase and glutathione reductase by moniliformin

The yeasts of patients with oral cancer has been studied before and during Xr-therapy. Gram and PAS smears revealed an increase of yeast-like structures, during treatment, from 56% to 66% of the cases. Before radiotherapy oral yeasts were isolated from 56% of the patients with cancer represented by Candida albicans (30%); C. tropicalis (12%); C. glabrata and C. krusei (4%), besides six other different species (2%). During radiotherapy yeasts were isolated in 72% of the cases, as follow: C. albicans (36%); C. tropicalis (16%); Rhodotorula rubra (6%); C. kefyr; C. krusei and Pichia farinosa (4%), besides other nine species (2%). C. albicans serotype A represented 93% of the isolated samples, before treatment and 88,8% during Xr-therapy.     

Development of an L6 myoblast in vitro model of moniliformin toxicosis

L6 myoblasts were used as an in vitro model to investigate the role of moniliformin and its interaction with monensin in turkey knockdown syndrome and sudden death syndromes in poultry. Cell viability and microscopic and ultrastructural alterations noted in L6 myoblasts cultured in the presence of moniliformin (0.0–0.3 g/l) were compared to those observed in parallel cultures also containing one of the following compounds: selenium (0–0.004 ng/l), thiamine (0–0.3 g/l), or pyruvate (0–0.46 g/l). Marked dilation of the RER, membranous whorls, glycogen deposition, membrane-bound cytoplasmic inclusions and necrosis were observed in myoblasts exposed to 0.03/2-0.30 g moniliformin/l medium. Supplementation of medium with thiamine and pyruvate, or selenium, provided significant protection to cells exposed to 0.0–0.3 g/l or 0.0–0.15 g moniliformin/l, respectively. Dose-dependent differences in protein and ATP production were not detected. Myoblasts grown in medium containing 0–0.15 g moniliformin/l and 7.5–50.0 M A23187, beauvericin or monensin had degrees of cytotoxicity similar to parallel cultures receiving only an ionophore. L6 myoblasts were a useful model of moniliformin toxicosis. The findings of this study suggest cytotoxicity due to moniliformin in L6 myoblasts may be due in part to oxidative damage and altered pyruvate metabolism, and that moniliformin does not predispose myoblasts to ionophore toxicosis. This study supports the results of in vivo investigations in poultry that moniliformin and monensin do not act synergistically to induce knockdown or monensin toxicosis.     

小球藻生物富集锌、镉机制的研究

藻类对许多重金属具有较强的生物富集能力,小球藻（Chlorella spp.)分别在不同系列Zn^2 ,Cd^2 浓度下培养8d间隔2d,测定小球藻的生物量及Zn和Cd的含量。结果表明,小球藻随水体中Zn^2 和Cd^2 的浓度不同,在重重金属水体中暴露时间不同,具有不同的富集速率和能力。     

Survey of moniliformin in wheat- and corn-based products using a straightforward analytical method

A straightforward analytical method was developed and validated to determine the mycotoxin moniliformin in cereal-based foods. Moniliformin is extracted with water and quantified with liquid chromatography tandem mass spectrometry, and its presence confirmed with liquid chromatography-Orbitrap-high-resolution mass spectrometry. The method was validated for flour, bread, pasta and maize samples in terms of linearity, matrix effect, recovery, repeatability and limit of quantification. Quantification was conducted by matrix-matched calibration. Positive samples were confirmed by standard addition. Recovery ranged from 77 to 114% and repeatability from 1 to 14%. The limit of quantification, defined as the lowest concentration tested at which the validation criteria of recovery and repeatability were fulfilled, was 10 μg/kg. The method was applied to 102 cereal-based food samples collected in the Netherlands and Germany. Moniliformin was not detected in bread samples. One of 22 flour samples contained moniliformin at 10.6 μg/kg. Moniliformin occurred in seven out of 25 pasta samples at levels around 10 μg/kg. Moniliformin (MON) was present in eight out of 23 maize products at levels ranging from 12 to 207 μg/kg.     

当药黄素抗抑郁作用研究

研究当药黄素的抗抑郁作用及其可能的作用机制。研究采用动物行为绝望模型评价当药黄素抗抑郁活性;采用药物交互作用模型探讨其主要作用环节及其可能的作用机制。结果显示当药黄素没有中枢神经兴奋性,能缩短小鼠悬尾和强迫游泳的不动时间;增加5-HTP诱导的小鼠甩头次数,可拮抗利血平引起的小鼠体温下降和眼睑下垂,对育亨宾毒性具有增强作用,但对盐酸色胺所致大鼠惊厥无影响。上述结果表明当药黄素具有抗抑郁活性,其抗抑郁活性可能与抑制5-羟色胺重摄取、增强脑内神经递5-HT神经功能和影响去甲肾上腺素有关;而与抑制体内单胺氧化酶活性无关。     

The toxicological evaluation of mutagenic events

At present no mammalian test system which meets the toxicological requirements is available for routine testing of mutagenicity. Therefore, emphasis should be laid primarily on basic research in this area and not on large-scale screening of possible mutagens with methods known to be inadequate in many respects, if mutagenicity is a major hazard to man, a view certainly not shared by all toxicologists.Furthermore, if carcinogenicity is based on a mutagenic event occurring in somatic cells, the well established tests for carcinogenicity would provide a better way for evaluating irreversible somatic mutations than the tests now suggested for mutagenicity testing.In the present situation a drastic reduction of the noxes men are exposed to would be the most reliable means of preventing a toxicological disaster. We are still in the situation of continuously performing “mass human experiments” and detecting hazards only after considerable harm has been done. Consequently, the goal must be neither to expose a considerable proportion of our population to environmental hazards nor to give drugs to thousands or even millions of healthy people for any reasons whatsoever, unless test systems are available which would allow effective prevention of disaster.     

Comparative cytotoxicity of fumonisin B1 and moniliformin in chicken primary cell cultures

Two water-solubleFusarium metabolites, fumonisin B₁ (FB₁) and moniliformin (MN) were compared for their cytotoxicity in a variety of chicken primary cell cultures. Cardiac and skeletal myocytes and hepatocytes derived from embryos, and splenocytes, macrophages, and chondrocytes derived from 3-to 4-week old chickens were cultured in media containing either FB₁ or MN (0 to 1 mM) for 48 hr. The colorimetric tetrazolium cleavage assay was then used for measuring cell survival. FB₁ was not toxic to macrophages, hepatocytes, cardiac and skeletal myocytes but toxic to splenocytes and chondrocytes. MN was not toxic to chondrocytes and macrophages, but toxic to splenocytes, cardiac and skeletal myocytes. Median effective concentration (EC₅₀) of MN in skeletal myocytes was 42 µM (fiducial limits: 33 to 50 µM) and in cardiac myocytes was 95 µM (fiducial limits: 84 to 122 µM). Estimated EC₅₀ of FB₁ in chondrocytes and splenocytes and EC₅₀ of MN in splenocytes were all greater than 200 µM.     

Simultaneous analysis of beauvericin and moniliformin in fungal cultures and in cereal grain samples

Species ofFusarium subglutinans andFusarium proliferation have been found to produce two mycotoxins, beauvericin and moniliformin, under labolatory conditions as well as in infected ears. A method for simultaneous extraction, analysis and quantitation of both metabolites was elaborated. Recoveries were 85–97 % and 78–94 % for the first and the latter mycotoxin, respectively. Detection limit of beauvericin on high- performance thin- layer chromatography plates (Merck 5633) after exposure to iodine vapours was 3 μg/g and by high- performance liquid chromatography method 0.07 μg/g while moniliformin was analyzed at concentration level 1 μg/g by thin- layer chromatography and 0.05 μg/g by high- performance liquid chromatography method.     

胆囊息肉病理分析及治疗对策的研究

目的:探讨胆囊息肉的手术指征.方法:统计分析2004年01月-2008年12月间因胆囊息肉而手术病例的病理资料,通过病理类型的分布规律及大小,探求手术指征的安全标准.结果:共316例患者入组,7例胆囊癌病例中,直径均大于1.5CM.良性息肉直径在0.3-1.7CM之间,平均0.82CM.阴性病理结果占8%,良性病变占89.8%,恶性者2.2%.其中胆固醇息肉72%,腺瘤3%.炎性增生14.8%.结论:控制胆囊息肉手术指征放宽的趋势,小于1.2CM的胆囊息内建议随诊,1.2-1.5CM者,仍可采取密切随诊的措施.大于1.5CM者,采取手术治疗,有术中快速病理的腹腔镜胆囊切除术是安全的.     

柠檬提取物抑菌、杀灭病毒作用机制研究

目的观察柠檬提取物对细菌生物膜的消除作用,对柠檬提取物抑制多重耐药金黄色葡萄球菌的机制进行初步研究,以及对环境中富集的病毒消除作用的研究。方法采用高分子滤膜法制备金黄色葡萄球菌生物膜后,加入柠檬提取物分别作用1、2和3h,通过细菌菌落计数判定不同生物膜的细菌存活数;采用SDS—PAGE电泳法,观察在柠檬提取物作用下菌体蛋白质的变化;EcoRⅠ酶切金黄色葡萄球菌DNA,观察酶切图谱的改变;在低渗环境下动态观察柠檬提取物在不同作用时间对细菌细胞壁的影响;通过柠檬提取物对病毒作用后RNA量的变化,说明柠檬提取物具有杀灭病毒的作用。结果柠檬提取物对生物膜中的细菌具有杀菌作用,且随作用时间的延长而逐渐增强;柠檬提取物对细菌蛋白质的组成和表达量均有一定影响,同时细菌DNA的EcoRⅠ酶切图谱发生改变;柠檬提取物作用15min时细菌呈现明显的胞壁缺损现象,即细菌个体胀大,呈现大球形;经柠檬提取物作用后,RNA病毒被杀灭。结论结果显示柠檬提取物对耐药金黄色葡萄球菌所形成的生物膜具有明显抑制作用;在柠檬提取物作用下,菌体蛋白合成量发生改变,同时对细菌的DNA和细胞壁有明显的影响。柠檬提取物处理病毒悬液后,病毒RNA量显著减少,说明病毒RNA结构被破坏。     

Purified moniliformin does not affect the force or rate of contraction of isolated guinea pig atria

Aspergillus flavus Link ex Fries and A. parasiticus Speare can invade peanut kernels and under certain environmental conditions produce unacceptable levels of the mycotoxin aflatoxin. A concerted effort is underway to reduce aflatoxin contamination in peanut and peanut products. A potentially effective method of control in peanut is the discovery and use of genes for resistance to either fungal invasion or aflatoxin formation. The objective of the present experimental study was to develop an effective and efficient procedure for screening individual plants or pods of single plants for resistance to invasion by the aflatoxigenic fungi and subsequent aflatoxin production. Methods of obtaining adequate drought-stress and fungal infection were developed through this series of experiments. By completely isolating the pods from the root zone and imposing drought-stress only on pegs and pods, high levels of fungal infection were observed. High amounts of preharvest aflatoxin accumulation were also produced by completely isolating the pods from the root zone. Mid-bloom inoculation with A. parasiticus-contaminated cracked corn and drought-stress periods of 40 to 60 days were the most effective procedures. This technique was used to assess peanut genotypes previously identified as being partially resistant to A. parasiticus infection or aflatoxin contamination, and segregating populations from four crosses. Variability in aflatoxin contamination was found among the 11 genotypes evaluated, however, none were significantly lower than the standard cultivars. Broad-sense heritability of four crosses was estimated through evaluation of seed from individual plants in the F₂ generation. The heritability estimates of crosses GFA-2 × NC-V11 and Tifton-8 × NC-V11 were 0.46 and 0.29, respectively, but mean aflatoxin contamination levels were high (73,295 and 27,305 ppb). This greenhouse screening method could be an effective tool when genes for superior aflatoxin resistance are identified.Cooperative investigation of the USDA-ARS and the University of Georgia, College of Agriculture.