Enzyme-linked immunosorbent assay detection and bioactivity of Cry1Ab protein fragments

Authors: ALBRIGHT, VURTICE - Iowa State University; Hellmich Ii, Richard; COATS, JOEL - Iowa State University

Submitted to: Environmental Toxicology and Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/17/2016
Publication Date: 7/19/2016
Citation: Albright, V.C., Hellmich II, R.L., Coats, J.R. 2016. Enzyme-linked immunosorbent assay detection and bioactivity of Cry1Ab protein fragments. Environmental Toxicology and Chemistry. doi: 10.1002/etc.3497.

Interpretive Summary: Use of transgenic crops has led to an increased interest in the fate of Cry proteins in the environment. Enzyme-linked immunosorbent assay (ELISA) has emerged as the preferred detection method for Cry proteins in environmental matrices. Concerns exist that ELISAs are capable of detecting fragments of Cry proteins, which may lead to an over-estimation of the concentration of these proteins in the environment. Five model systems were used to generate fragments of the Cry1Ab protein, which were then analyzed by ELISAs and bioassays. The fragments from four of the model systems were not detectable by ELISA and did not retain bioactivity. In the proteinase K model system, the fragments generated were detectable by ELISA and retained bioactivity. The reason for this is not yet known. Despite this result, ELISAs appear to provide an accurate estimation of the amount of Cry proteins in the environment, as detectable fragments retained bioactivity, and non-detectable fragments did not retain bioactivity. This information is useful for all growers and scientists interested in the environmental risk assessment of transgenic crops.

Technical Abstract: Enzyme-linked immunosorbent assay (ELISA) has emerged as the preferred detection method for Cry proteins in environmental matrices. Concerns exist that ELISAs are capable of detecting fragments of Cry proteins, which may lead to an over-estimation of the concentration of these proteins in the environment. Five model systems were used to generate fragments of the Cry1Ab protein, which were then analyzed by ELISAs and bioassays. In four of these model systems, the chymotrypsin model system, acidic buffer model system, photo degradation model system, and long-term degradation in buffer model system, the fragments generated were not detectable by ELISA and did not retain bioactivity. In the proteinase K model system, the fragments generated were detectable by ELISA and retained bioactivity. The reason for this is not yet known. Despite this result, ELISAs appear to provide an accurate estimation of the amount of Cry proteins in the environment, as detectable fragments retained bioactivity, and non-detectable fragments did not retain bioactivity.