Method for testing trace Bt (bacillus thuringiensis) toxic protein in bodies of insects in transgenic Bt crop habitat

Abstract

A method for testing trace Bt toxic protein in the bodies of insects in a transgenic Bt crop habitat includes the following steps: in the first step, collecting insects to be tested growing in a transgenic Bt crop field, and preparing insect liquid to be tested; in the second step, collecting insects growing on non-transgenic Bt plants in a lab, which belong to the same species or variety as the insects to be tested, and preparing contrast insect liquid; in the third step, using the contrast insect liquid to prepare standard Bt toxic proteins with a series of concentrations; in the fourth step, utilizing an enzyme immunoassay method to determine the optical density values of the standard Bt toxic proteins and the insect liquid to be tested at the wavelength of 650 nanometers; in the fifth step, obtaining a standard equation according to the concentrations of the standard Bt toxic proteins and the corresponding optical density values, and calculating the Bt toxic protein concentration in the insect liquid to be tested according to the standard equation. The test method has extremely high sensitivity and good repeatability.

Description

technical field [0001] The invention relates to the field of biotechnology, in particular to a method for detecting trace amounts of Bt toxin protein in insects in the habitat of transgenic Bt crops. Background technique [0002] In the prior art, enzyme-linked immunosorbent assay (ELISA for short) is usually used to detect the Bt protein content in crops. Among them, the double-antibody sandwich method ELISA kit is more commonly used, and its assay principle is the solid phase of the antigen. and enzymatic labeling of antigens. In this method, the antigen combined on the surface of the solid phase carrier still maintains its immunological activity, and the enzyme-labeled antigen or antibody retains both its immunological activity and enzyme activity; or antigen) reacts with the antigen or antibody on the surface of the solid phase carrier, and the antigen-antibody complex formed on the solid phase carrier is separated from other substances in the liquid by washing; then th...

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Problems solved by technology

[0003] However, its disadvantage is that it is difficult to measure the Bt poisonous protein content in non-target pests or natural enemy insects

Because some non-target natural enemy insects feed on Bt crops indirectly, or some pests consume very little Bt poisonous protein due to different feeding methods, such as eating different parts of Bt crops, the Bt in these pests or natural enemy insects The content of toxic protein is generally below 1 nanogram per gram of body weight, while the minimum detection limit of the existing enzyme-linked immunosorbent assay is above 1.2 nanograms per gram of body weight

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