Method for identifying and evaluating toxigenic capability of toxigenic strain of aflatoxin

A technology of aflatoxin and Aspergillus flavus strains, applied in the biological field, can solve the problems of gene deletion and false results related to toxin production, and achieve the effects of optimizing the experimental process and structure, reliable ratio results, and accurate identification and evaluation

Active Publication Date: 2019-04-02
INST OF OIL CROPS RES CHINESE ACAD OF AGRI SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the disadvantage of this type of method is that in the natural state, there is a deletion of toxin-related genes other than the Nor-1 gene, so that even if the expression of the Nor-1 gene is detected, it still does not naturally produce aflatoxin. resulting in spurious results of such methods

Method used

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  • Method for identifying and evaluating toxigenic capability of toxigenic strain of aflatoxin
  • Method for identifying and evaluating toxigenic capability of toxigenic strain of aflatoxin
  • Method for identifying and evaluating toxigenic capability of toxigenic strain of aflatoxin

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] 1. The research has proved that the ratio of aflatoxin production to Nor-1 gene transcription has very good relative stability

[0038] Weigh 1g NaNO 3 , 1g K 2 HPO 4 , 0.5g MgSO 4 ·7H 2 O, 0.5g KCl, 0.01g FeSO 4 , 30 g of glucose and 20 g of agar powder were made up to a total volume of 1000 ml with deionized water, and sterilized by high-temperature steam at 121° C. for 30 minutes to prepare a CDA medium. The Aspergillus flavus strain was cultivated for 10 days at 28° C. and 90% humidity with CDA solid culture, and then the culture plate was washed with 20% Tween-20 to obtain the Aspergillus flavus spore solution. The Aspergillus flavus spore solution was oscillated evenly with a vortex shaker by the hemocytometer plate counting method, and the Aspergillus flavus spore solution was microscopically counted with a microscope.

[0039] Put 15mL potato dextrose liquid culture medium in a 50mL Erlenmeyer flask, autoclave at 121°C for 30min, add Aspergillus flavus spo...

Embodiment 2

[0046] The establishment of the simultaneous detection RT-PCR method of embodiment 2 aflatoxin output and Nor-1 gene transcription amount

[0047] Using the existing phage VHH 2-5 displaying aflatoxin anti-idiotypic nanobody on the surface and the nor-1 gene DNA fragment Tq-nor1, a RT-PCR method for simultaneous detection of aflatoxin production and Nor-1 gene transcription was established According to the above detection results as the scientific basis for the identification and evaluation of the virulence of Aspergillus flavus strains, it provides method support for the rapid identification and evaluation of the virulence of Aspergillus flavus strains. These specific steps are as follows.

[0048] The phage VHH 2-5 displaying aflatoxin anti-idiotypic nanobodies on the surface was developed by the Quality Inspection Center of the Institute of Oil Crops, Chinese Academy of Agricultural Sciences, and has been published in the journal literature "Yanru Wang; Peiwu Li; ZuzanaMajk...

Embodiment 3

[0097] 1. The comparative analysis of the virulence of Aspergillus flavus was evaluated by Nor-1 transcript and AFT / Nor-1 (ratio of toxin production and nor-1 transcript) respectively

[0098] Through the comparative analysis of the results, we found that if the virulence of Aspergillus flavus was evaluated only from the amount of nor-1 transcript, the identification result was unreliable. For example, in Aspergillus flavus strains Pc124-2 and Pc34-1, the logarithms of the copy number of nor-1 gene expression were 7.85±0.52 and 6.75±0.58, respectively, and the expression levels of nor-1 gene in the two strains were similar; The yield of aspergillus toxin was 66.5±4.93ng / mL, and the amount of aflatoxin produced by Pc34-1 was only 19.69±2.27ng / mL; in addition, no aflatoxin was detected in CY1, CY2, Pg28-1 and Pc321-1-3 strains. Aspergillus-producing, however, Pg28-1 and Pc321-1-3 expressed even higher levels of the nor-1 gene than some of the aflatoxin-producing strains.

[009...

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Abstract

The invention, which belongs to the biological field, particularly relates to a method for identifying and evaluating the toxigenic capability of a toxigenic strain of aflatoxin. A ratio of the aflatoxin yield to the Nor-1 gene transcription amount is determined and the high relative stability is realized. An aflatoxin strain toxigenic capability identification model is established and thus a regression equation between the aspergillus flavus toxigenic capability and the AFT / Nor-1 ratio is obtained. With determination of the AFT / Nor-1 ratio, the toxigenic capability of the aspergillus flavus strain is identified and evaluated rapidly and accurately, so that the method has the important significance in aflatoxin pollution early warning and prevention controlling. Besides, a synchronous detection RT-PCR method for the aflatoxin yield and the nor-1 gene transcription amount is also established; and the AFT / Nor-1 ratio obtained based on the synchronous detection RT-PCR method is reliable and accurate and can be used as the identification index for determining the toxigenic capability of the aspergillus flavus strain.

Description

technical field [0001] The invention belongs to the field of biology, and in particular relates to a method for identifying and evaluating the toxicity of aflatoxin-producing strains. Background technique [0002] Aflatoxin is the most toxic type of mycotoxin found so far. Taking aflatoxin B1 as an example, its toxicity is 10 times that of potassium cyanide and 68 times that of arsenic. It is listed as a class I carcinogen by the International Cancer Organization. Aflatoxins can easily contaminate grain and oil crops such as peanuts, corn, and rice, and also contaminate many plant products such as walnuts, pistachios, and Chinese herbal medicines. There have been many cases of human and livestock poisoning incidents caused by aflatoxin at home and abroad. According to the latest report from the International Agency for Research on Cancer (IARC), about 500 million people in developing countries alone are at risk of exposure to aflatoxins. my country is an area heavily pollu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N33/577G01N33/569C12Q1/6895C12Q1/04C12R1/67
CPCG01N33/56961G01N33/577C12Q1/6895C12Q2600/142G01N2333/38C12Q1/686
Inventor 张奇李培武白艺珍李慧姜俊张文
Owner INST OF OIL CROPS RES CHINESE ACAD OF AGRI SCI
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