串珠镰刀菌产伏马菌素和二相性真菌特性

目的 研究串珠镰刀菌产生伏马菌素和二相性真菌的致病性。方法 用间接竞争酶联吸附法测定从浙江省粮食中分离的 珠镰刀菌产竹的优良马菌素。结果 串珠镰刀菌产生的伏刀菌素Ｂ１〉４００μｇ／ｇ。１０份样品的串珠镰刀菌检出率在２￣１００％之间,伏马菌素Ｂ１污染量在３．７￣１４３．１μｇ／ｇ中珠刀菌在９％ＮａＣｌ沙保琼脂平板上３７℃培养可形成酵母样菌落,以出芽繁殖为主;在血平板上２可形成草绿色溶血反应。尚未见到     

部分市售粮食中伏马菌素污染状况调查

测定谷物中伏马菌素含量,了解粮食中有关真菌的污染状况,评价伏马菌素的ＥＬＩＳＡ测定法。方法：采集市售大米,玉米及饲料玉米,采用酶联免疫吸附法测定,对阳性样品进行真菌培养分离,并用ＨＰＬＣ进行确证。结果：４０份大米中未检出伏马菌素,７０份玉米检出阳性样品２７份,均数０．６８ｍｇ／ｋｇ。ＨＰＬＣ法的确证结果表明２７份ＥＬＩＳＡ法阳性样品中２３份检出伏马毒素Ｂ１,均数为０．４２ｍｇ／ｋｇ;６份同时检出伏马菌素Ｂ２,均数为０．２ｍｇ／ｋｇ。２７份阳性样品真菌分离培养结果均检出串珠镰刀菌。结论：玉米受串珠镰刀菌污染较重,并有伏马菌素产生。本次调查大米中未检出伏马菌素情况较好。其它主粮中伏马菌素污染情况还有待进一步调查。     

串珠镰刀菌伏马菌素产毒基因及毒力的测定

目的研究我国串珠镰刀菌分离株伏马菌素产毒性与其生物合成酶基因fum5的关系。方法对不同省区、不同粮食样品中分离的29株串珠镰刀菌进行了产毒基因的测定,对其中18株产毒基因阳性株进行了伏马菌素生物合成,并用高效液相色谱法进行了毒素测定。结果26株为fum5基因阳性。除1株仅产生低水平的伏马菌素FB1外,其他菌株都产生不同水平的伏马菌素FB1、FB2和FB3,产毒量范围分别为0．41～140．20mg／kg、0．06～14．30mg／kg和0．30～58．00mg／kg。从芝麻中分离并鉴定了1株串珠镰刀菌伏马菌素强产毒株,分别产生高水平的伏马菌素FB1、FB2和FB3,产毒量分别达到128．84、11．80和14．88mg／kg。结论我国串珠镰刀菌分离株产生伏马菌素的能力与其生物合成酶基因rum5有密切关系。串珠镰刀菌可以污染芝麻并产生高水平的伏马菌素。     

ELISA法测定谷物中伏马毒素

为测定谷物中伏马毒素含量，了解粮食中有关真菌的污染状态，评价伏马毒素的ＥＬＩＳＡ测定法。采集市售大麦、玉米及饲料玉米，采用酶联免疫吸附法测定，对阳性样品进行真菌培养分离，并用ＨＰＬＣ进行确证。结果：４０份大米中未检出伏马毒素，７０份玉米检出阳性样品２７份，均数０．６８ｍｇ／ｋｇ。ＨＰＬＣ法的确证结果表明２７份ＥＬＩＳＡ法阳性样品中２３份检出伏马毒素Ｂ１，均数为０．４２ｍｇ／ｋｇ；６份同时检出伏马毒素Ｂ２，均数为０．２ｍｇ／ｋｇ。２７份阳性样品真菌分离培养结果均检出串珠镰刀菌。结论：玉米受串珠镰刀菌污染较重，并可有伏马毒素产生。本次调查大米中未检出伏马毒素，情况较好。其它主粮中伏马毒素污染情况还有待进一步调查     

伏马菌素污染情况及其毒性研究进展

伏马菌素是串珠镰刀菌产生的一类霉菌毒素，它可以污染玉米及其制品，也可以污染其他粮食及其制品，与黄曲霉毒素的共同污染状况也很严重。伏马菌素可以引起动物的急、慢性毒性，因动物的种类不同而作用的靶器官也不相同。不同的伏马菌素间毒性存在差异，伏马菌素与其他霉菌毒素也存在联合作用。     

四川省部份主肿霉菌及其毒素污染状况调查

报道了四川省部分地区玉米，小麦，大米３种主要粮食中霉菌侵染状况和伏马菌素Ｂ１（ＦＢ１）杂色曲霉素（ＳＴ），烟曲霉震颤素（ＦＴ）３种霉菌毒素的污染状况。结果显示３种粮食中毒菌侵染严重、其侵染率分别为９２．３％，８７２％，７２．４％，菌相以曲霉菌为主，同时检出了产生ＳＴ毒素的杂色曲霉菌。     

串珠镰刀菌及伏马菌素在吉林省主粮中的生态学分布调查

自全省三个地区新陈小麦、玉米、水稻170份样品分离霉菌，共检出串珠镰刀菌及其交孢变种99株，其中新玉米检出75株占它检出总数的75．8％，各样品中伏马菌素（FB1）检测结果阳性率以陈小麦最高，100％，平均在30％－63．3％平均含毒量在7．90－9．95mg/kg之间，各种样品的平均含毒量相差不大。菌株的FB1测定结果阳性率100％平均含毒量为26.85mg/kg，远远高于各样品平均含毒量。     

湖北省粮食中霉菌毒素调查分析

目的：调查湖北省粮食中主要霉菌及毒素污染情况。方法：采取随机分层定点方法采集大米、小麦、玉米共182份样品,按卫生部营卫所提供的方法进行毒素测定。结果：三种粮食中串珠镰刀菌素B平均污染率为39．75％,杂色曲霉素为78．57％。黄曲霉毒素B1为80．36％。结论：三种粮食中串珠镰刀菌素B、杂色曲霉素和黄曲霉素污染均较严重。     

串珠镰刀菌伏马菌素产毒株分子遗传学研究进展

伏马菌素是一组主要由串珠镰刀菌产生的真菌毒素。伏马菌素B1对某些牲畜有急性毒性及潜在的致癌性 ,如引起马脑白质软化症、猪肺水肿或大鼠肝癌 ,流行病学研究认为其与人类食管癌的高发有关。目前国际上对伏马菌素的研究已经深入到分子水平 ,通过对串珠镰刀菌伏马菌素产毒株的遗传学研究 ,鉴定了 4个与伏马菌素生物合成相关的基因fum1、fum2、fum3和fum4及由 4个基因fum6、fum7、fum8和fum9所组成的伏马菌素生物合成协同调节基因蔟。应用简并PKS引物 ,进行PCR扩增 ,证明fum5为伏马菌素生物合成所必需的多酮肽合成酶基因。并对串珠镰刀菌伏马菌素产毒株进行了分子生物学研究。还通过转基因技术来控制串珠镰刀菌感染及伏马菌素生成 ,以减少对人、动物健康及食品安全的危害。     

四川省部份主粮中霉菌及其毒素污染状况调查

报道了四川省部分地区玉米、小麦、大米３种主要粮食中霉菌侵染状况和伏马菌素Ｂ_１（ＦＢ_１）、杂色曲霉素（ＳＴ）、烟曲霉震颤素（ＦＴ）３种霉菌毒素的污染状况。结果显示３种粮食中霉菌侵染严重,其侵染率分别为９２．３％、８７．２％、７２．４％。菌相以曲霉菌为主,同时检出了产生ＳＴ毒素的杂色曲霉菌。ＦＢ１和ＳＴ在粮食中污染较普遍,ＦＢ_１检出率为１２．８％～１００％,含量１５．２～２７．０ｍｇ／ｎｇ;ＳＴ检出率为３４．３％～５６．９％,含量２４．０～７５．０μｇ／ｋｇ。ＦＴ在粮食中污染率和含量均较低。     

串珠镰刀菌伏马菌素产毒株聚合酶链反应检测方法的研究

以伏马菌素生物合成所必需的多酮肽合成酶基因fum5为基础 ,设计了 3对特异性引物P1 P2、P3 P4和Fum5F2 1 Fum5 1,建立了串珠镰刀菌伏马菌素产毒株PCR检测方法。以 5株ATCC典型串珠镰刀菌及其他菌株为参考 ,其中ATCC 5 2 5 3 9为伏马菌素B1(FB1)产毒株 ,测定了PCR方法的特异性。ATCC 5 2 5 3 9扩增结果阳性 ,该 3对引物分别扩增出 880bp、70 2bp和 10 40bpDNA片段 ,非伏马菌素产毒株ATCC 3 8946、ATCC2 62 63、ATCC 12 763、ATCC 3 80 16及其他阴性对照菌株 (禾谷镰刀菌、梨孢镰刀菌、木贼镰刀菌、三线镰刀菌、黄曲霉、拟青霉和大肠杆菌O15 7)结果阴性 ,证明引物具有很好的特异性。同时以不同稀释度的ATCC 5 2 5 3 9DNA为模板 ,测定了 3对引物PCR的敏感性 ,P1 P2每PCR反应的检出限为 10 0pg ,P3 P4和Fum5F2 1 Fum5R1每PCR反应的检出限均为 10pg ,分别相当于每PCR反应检出 10 4和 10 3个孢子。 3对引物PCR检测国内不同地区分离的 3 2株串珠镰刀菌及交孢变种 ,2 6株为伏马菌素产毒株 ,6株为非伏马菌素产毒株。并对部分产毒株PCR(P3 P4)产物 ,应用内切酶EcoRV和BamHI,进行限制片段长度多态性 (RFLP)分析 ,分别产生 181bp、5 2 1bp 2个和 116bp、2 5 8bp、3 2 8bp 3个DNA片段 ,与文献报道值一致 ,确证了结     

Compensatory regeneration as a mechanism for renal tubule carcinogenesis of fumonisin B1 in the F344/N/Nctr BR rat

Fumonisin B1(FB1) is a fungal metabolite of Fusarium verticillioides (= F. moniliforme), a fungus that grows on many crops worldwide. Previous studies demonstrated that male BD IX rats consuming diets containing 50 ppm fumonisin B1 developed hepatocellular carcinomas. In our recent studies, diets containing FB1 at 50 ppm or higher concentrations induced renal tubule carcinomas in male F344/N/Nctr BR rats and hepatocellular carcinomas in female B6C3F1/Nctr BR mice. The carcinogenicity of FB1 in rats and mice is not due to DNA damage, as several laboratories have demonstrated that FB1 is not a genotoxin. FB1 induces apoptosis in cells in vitro. Including FB1 in the diets of rats results in increased hepatocellular and renal tubule epithelial cell apoptosis. In studies with F344/N/Nctr BR rats consuming diets containing up to 484 ppm FB1 for 28 days, female rats demonstrated more sensitivity than male rats in the induction of hepatocellular apoptosis and mitosis. Conversely, induction of renal tubule apoptosis and regeneration were more pronounced in male than in female rats. Induction of renal tubule apoptosis and hyperplasia correlated with the incidence of renal tubule carcinomas that developed in the 2-year feeding study with FB1 in the F344/N/Nctr BR rats. The data are consistent with the hypothesis that the induction of renal tubule carcinomas in male rats could be partly due to the continuous compensatory regeneration of renal tubule epithelial cells in response to the induction of apoptosis by fumonisin B1.     

Fumonisin toxicosis in swine: an overview of porcine pulmonary edema and current perspectives

Fumonisin toxicosis in swine was named porcine pulmonary edema (PPE) after outbreaks of a fatal disease in pigs fed Fusarium verticillioides (F. moniliforme)-contaminated corn screenings from the 1989 corn crop in Iowa, Illinois, and Georgia. Pigs that died had severe pulmonary edema, which has not been identified in other species after exposure to fumonisins. The disease has been reproduced experimentally by feeding of naturally contaminated corn, F. verticillioides culture material, and by intravenous administration of fumonisin B1 (FB1). Hepatic lesions consisting of apoptosis, necrosis, and hepatocyte proliferation also are observed. As in other species, alterations in clinical pathology reflect hepatic injury as well as elevated serum cholesterol concentration. In chronic studies, esophageal plaques, hyperplastic hepatic nodules, and right ventricular hypertrophy were found. In pigs, as in other species, fumonisin alters sphingolipid biosynthesis, with the greatest alterations in sphingosine and sphinganine concentrations in kidney, liver, lung, and heart. Our recent studies on fumonisin toxicosis in pigs have focused on immune effects and the pathogenesis of pulmonary edema. The specific immune system was not affected; however, FB1 inhibited phagocytosis and sphingolipid biosynthesis in pulmonary macrophages. Fumonisin induced an accumulation of membranous material in pulmonary capillary endothelial cells; this change appears specific to this cell type and to swine. In short-term cardiovascular studies, fumonisin decreased left ventricular dP/dt(max) (an index of cardiac contractility), mean systemic arterial pressure, heart rate, and cardiac output, and increased mean pulmonary artery pressure and pulmonary artery wedge pressure. These changes are compatible with the inhibition of L-type calcium channels by increased sphingosine and/or sphinganine concentration. Therefore, fumonisin-induced pulmonary edema in swine appears to result from acute left-sided heart failure mediated by altered sphingolipid biosynthesis.     

我国部分克山病区和非病区主粮中霉菌的污染调查

自克山病地区及非病区的291份稻谷和玉米样品中分离霉菌,菌相分析未发现各菌群中有意义的地区性差异。产生串珠镰刀菌素(moniliformin,简称 MF)的串珠镰刀菌及其变种的检出率,玉米比稻谷高约10倍。该类菌的分离结果与样品中 MF 的测定结果基本平行。二者对比说明,该菌的产毒株在病区可能比非病区多。     

抗伏马菌素B_1单克隆抗体的制备及试剂盒的研制

目的为了能够快速检测粮谷类食品中伏马菌素B_1的污染水平,研制具有我国自主知识产权的针对伏马菌素B_1快速检测试剂盒。方法制备了能分泌抗伏马菌素B_1单克隆抗体的杂交瘤细胞株,建立了敏感、特异、快速的酶联免疫吸附试验检测方法,最终形成具有中国自主知识产权的伏马菌素B_1快速检测试剂盒。结果该试剂盒所用单克隆抗体的Ig亚类为IgG1,亲和常数为8·3×10-8mol/L。该抗体与其他结构类似物无明显交叉反应,具有较高的特异性。试剂盒对伏马菌素B_1最低检出限5ng/ml,标准曲线的线性范围(50~500ng/ml),回归方程^Y=-0·582X+1·793(r=0·99,P<0·05);对玉米作50ng/ml,200ng/ml和500ng/ml3个加标浓度的回收率在71·89%~112·95%之间;试剂盒在常温状态下有效期至少10个月;实验室内的变异系数和实验室间的变异系数均小于20%。     

Factors that affect the occurrence of fumonisin

The two important Fusarium ear rots of corn, Gibberella ear rot (Fusarium graminearum, formally F. moniliforme and allied species) and Fusarium ear rot (F. verticillioides and allied species) grow under different environmental conditions. F. graminearum grows well only between 26 and 28 degrees C and requires rain both at silking and during disease progression. F. verticillioides grows well at higher temperatures, and ear rot and fumonisin accumulation are associated with drought and insect stress and growing hybrids outside their areas of adaptation. In southern Transkei, where esophageal cancer has been associated with the consumption of F. verticillioides and fumonisin-contaminated corn, environmental conditions favor this fungus in most years. In the nearby areas where the soils, crops, food consumption, and populations are the same and where esophageal cancer is low, temperatures are cooler and F. graminearum is favored. Although F. verticillioides is associated with a disease of corn, it may be that this fungus is a mutualistic endophyte of the plant. Perhaps because of this, breeding for resistance to Fusarium ear rot has produced inconclusive results to date. The best available strategies for reducing the risk of fumonisin contents of maize are to ensure that hybrids are adapted to the environment and to limit drought stress and insect herbivory. It may also be necessary to make use of alternative strategies such as producing hybrids that contain enzymes to degrade fumonisin as it is produced.