Aspergillus flavus mixed strain incapable of producing aflatoxin and application thereof

A technology of aflatoxin and mixed strains, applied in the direction of application, fungi, methods of using spores, etc.

Active Publication Date: 2014-07-23
INST OF AGRO FOOD SCI & TECH CHINESE ACADEMY OF AGRI SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, non-toxin-producing strains from different regions have a certain scope of application in inhibiting toxin-producing bacteria. For example, the non-toxin-producing bacteria screened in Africa can better inh...

Method used

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  • Aspergillus flavus mixed strain incapable of producing aflatoxin and application thereof
  • Aspergillus flavus mixed strain incapable of producing aflatoxin and application thereof
  • Aspergillus flavus mixed strain incapable of producing aflatoxin and application thereof

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Experimental program
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Effect test

Embodiment 1

[0066] The collection, separation, identification of embodiment 1, Aspergillus flavus strain AF-8 and AF-20

[0067] 1. Isolation of Aspergillus flavus strains AF-8 and AF-20 from peanut planting soil

[0068] AF-8 and AF-20 were used to isolate Aspergillus flavus strains from peanut planting soil in Hubei and Shandong provinces using DG18 medium. The specific operation is as follows:

[0069] 1. Preparation of soil sample bacterial suspension

[0070] Take 10g of soil sample, add 90mL of 0.1% peptone sterile water (w / v), shake at room temperature for 30min, and make 10 -1 bacteria suspension; then take 0.5mL10 -1 Add 4.5mL0.1% peptone sterile water to the bacterial suspension to prepare 10 -2 Bacteria suspension of dilution; prepare 10 as above -3 diluted bacterial suspension.

[0071] 2. Isolation and purification of strains

[0072] Take 0.1mL bacterial solution for each dilution, spread it on DG18 medium (recipe: 5.0g casein peptone, 10.0g anhydrous glucose, 1.0g po...

Embodiment 2

[0092] Identification of aflatoxin synthesis gene deletion in embodiment 2, Aspergillus flavus (Aspergillus flavus) AF-8 and AF-20

[0093] The inventors of the present invention have designed four pairs of primers for the toxin synthesis-related genes hypB, hypC, hypD and hypE with reference to the sequence of the toxin synthesis gene of Aspergillus flavus with the Genbank accession number AY510451. The primers of other genes refer to Perng-Kuang Chang (Chang , P.K., Horn, B.W. and Dorner, J.W. (2005) Sequence breakpoints in the aflatoxin biosynthesis gene cluster and flanking regions in nonaflatoxigenic Aspergillus flavus isolates. Fungal Genet Bio42, 914–923.). The 29 genes to be tested and their corresponding primer sequences are shown in Table 1.

[0094] Table 1 Primer sequences of different aflatoxin synthesis genes

[0095]

[0096]

[0097] Genomic DNA of Aspergillus flavus (Aspergillus flavus) AF-8CGMCC NO.8964 and Aspergillus flavus (Aspergillus flavus) AF-20...

Embodiment 3

[0103] Embodiment 3, Aspergillus flavus (Aspergillus flavus) mixed strain " AF-8+AF-20 " is to the inhibitory action of the Aspergillus flavus that produces aflatoxin in peanut

[0104] 1. Experimental method

[0105] (1) Preparation of peanuts

[0106] Select complete and undamaged peanut particles, then weigh 10g of peanuts of uniform size, disinfect the surface with 75% alcohol for 2min, dry them with sterile filter paper and put them into a sterilized 150ml Erlenmeyer flask; The moisture content in the bottle was adjusted to 25% (mass percentage), and the bottle was sealed with a biological safety film, and cultivated at 30°C for 7 days in a constant temperature and humidity chamber in the dark to observe the effect of surface disinfection. The results show that there is no growth of any miscellaneous bacteria on the surface of peanuts, and this method will be used for surface disinfection of samples in subsequent tests.

[0107] (2) Preparation of bacterial suspension ...

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Abstract

The invention discloses an Aspergillus flavus mixed strain incapable of producing aflatoxin. The mixed strain is formed by mixing Aspergillus flavus AF-8 and Aspergillus flavus AF-20; and the collection numbers of the Aspergillus flavus AF-8 and Aspergillus flavus AF-20 at China General Microbiological Culture Collection Center are respectively CGMCC No.8964 and CGMCC No.8966. The experiment proves that the mixed strain has an inhibiting action on toxin production of the Aspergillus flavus strain capable of producing aflatoxin; the mixture of the two strains has better inhibiting effect on the bacterium capable of toxin production than a single strain; and when the spore concentration ratio of the AF-8 and AF-20 incapable of toxin production to the GD-1 capable of toxin production is 5*10<4>:5*10<4>:1*10<5>, the toxin production inhibition rate of the mixed strain incapable of toxin production for the bacterium capable of toxin production is approximately 100%. The strain has important meanings for inhibiting the toxin production Aspergillus flavus from infecting the agricultural products and lowering the aflatoxin pollution in the agricultural products.

Description

technical field [0001] The invention belongs to the field of agricultural product safety, and relates to a mixed strain of Aspergillus flavus that does not produce aflatoxin and the application of the strain in inhibiting the toxin production of Aspergillus flavus. Background technique [0002] Aflatoxins (Aflatoxins, AFT) are mycotoxins produced by Aspergillus flavus, A. parasiticus, A. nonius and A. tamarii. Teratogenic, carcinogenic, mutagenic secondary metabolites. It often exists in soil, animals and plants, and various nuts, especially peanuts and walnuts. AFB has now been isolated 1 、AFB 2 、AFG 1 、AFG 2 、AFM 1 、AFM 2 18 kinds of aflatoxins with different structures, the most important of which is AFB 1 、AFB 2 、AFG 1 、AFG 2 . where AFB 1 Potassium is the most toxic, and its toxicity is 10 times that of potassium cyanide and 68 times that of arsenic. It is highly carcinogenic and can cause livestock diseases, resulting in huge economic losses. In 1993, af...

Claims

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Application Information

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IPC IPC(8): C12N1/14C12N3/00A23L1/015C12R1/67A23L5/20
Inventor 刘阳魏丹丹周露张初署邢福国赵月菊王龑
Owner INST OF AGRO FOOD SCI & TECH CHINESE ACADEMY OF AGRI SCI
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