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Abstract：
This study investigated the aflatoxin production potentials of selected fungi using a polyphasic approach. Internally transcribed spacer region of the fungi was amplified using the polymerase chain reaction. Forty-five Aspergillus strains were further assessed for aflatoxin production using the conventional methods such as growth on yeast extract sucrose, β-cyclodextrin neutral red desiccated coconut agar (β-CNRDCA); expression of the aflatoxin regulatory genes and the use of both thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). A large proportion (82.22%) of the isolates harbored the Nor-1 gene while 55.56%, 68.89%, and 80% possessed the ver-1, omt-A, and aflR genes, respectively. All 100% the isolates harbored the aflJ gene. Twenty-three isolates were positive for aflatoxin production based on the yeast extract sucrose medium (YES) test; ammonium vapor test (51%), yellow pigment production (75.5%), and β-CNRDCA tests; and blue/green fluorescence (57.7%). Based on TLC detection 42.2% produced aflatoxins while in the HPLC, total aflatoxin (AFTOT) production concentrations ranged from 6.77-71,453 µg/g. Detectable aflatoxin B1 (AFB1) concentrations obtained from the HPLC ranged between 3.76 and 70,288 µg/g; 6.77 and 242.50 µg/g for aflatoxin B2 (AFB2); 1.87 and 745.30 µg/g for aflatoxin G1 (AFG1); and 1.67 and 768.52 µg/g for aflatoxin G2 (AFG2). AFTOT contamination levels were higher than European Union tolerable limits (4 µg/kg). The regression coefficient was one (R2 = 1) while significant differences exist in the aflatoxin concentrations of Aspergillus (p ≤ 0.05). This study reports the potentials of Aspergillus oryzae previously known as a non-aflatoxin producer to produce AFG1, AFG2, AFB1, and AFB2 toxins. Aspergillus species in feedlots of animals reared for food are capable of producing aflatoxins which could pose hazards to health.
摘要：
这项研究使用多相方法调查了选定真菌的黄曲霉毒素产生潜力。使用聚合酶链反应扩增真菌的内部转录间隔区。使用常规方法，例如在酵母提取物蔗糖上生长，进一步评估了45株曲霉的黄曲霉毒素产量。β-环糊精中性红干燥椰子琼脂（β-CNRDCA）；黄曲霉毒素调节基因的表达以及薄层色谱（TLC）和高效液相色谱（HPLC）的使用。大部分(82.22%)的分离株携带Nor-1基因,55.56%,68.89%,80%拥有ver-1，omt-A，和aflR基因，分别。所有100%的分离株都带有aflJ基因。根据酵母提取物蔗糖培养基(YES)试验,23个分离株产黄曲霉毒素阳性;铵蒸气试验(51%),黄色素产量（75.5%），和β-CNRDCA测试;和蓝色/绿色荧光(57.7%)。基于TLC检测，在HPLC中产生了42.2%的黄曲霉毒素，总黄曲霉毒素（AFTOT）生产浓度范围为6.77-71,453µg/g。从HPLC获得的可检测黄曲霉毒素B1（AFB1）浓度范围为3.76至70,288µg/g；黄曲霉毒素B2（AFB2）为6.77和242.50µg/g；黄曲霉毒素G1（AFG1）为1.87和745.30µg/g；黄曲霉毒素G2（AFG2）为1.67和768.52µg/g。AFTOT污染水平高于欧盟的可容忍限值（4µg/kg）。回归系数为1（R2=1），而曲霉中黄曲霉毒素浓度存在显着差异（p≤0.05）。这项研究报告了先前被称为非黄曲霉毒素生产者的米曲霉产生AFG1，AFG2，AFB1和AFB2毒素的潜力。饲养的动物饲养场中的曲霉能够产生黄曲霉毒素，这可能对健康造成危害。
