A Label-Free Immunosensor Based on Gold Nanoparticles/Thionine for Sensitive Detection of PAT Protein in Genetically Modified Crops

Genetically modified (GM) crops containing phosphinothricin acetyltransferase (PAT) protein has been widely planted worldwide. The development of a rapid method for detecting PAT protein is of great importance to food supervision. In this study, a simple label-free electrochemical immunosensor for the ultrasensitive detection of PAT protein was constructed using thionine (Thi)/gold nanoparticles (AuNPs) as signal amplification molecules and electrochemically active substances. Under optimum conditions, the limits of detection of the sensor for soybean A2704-12 and maize BT-176 were 0.02% and 0.03%, respectively. The sensor could detect crops containing PAT protein and had no cross-reaction with other proteins. After storage at 4°C for 33 days, the sensor still retained 82.5% of the original signal, with a relative standard deviation (RSD) of 0.92%. The recoveries of the sensor for soybean A2704-12 and maize BT-176 were 85%–108% and 98%–113%, respectively. The developed PAT-target immunosensor with high sensitivity, specificity, and satisfactory reproducibility and accuracy will be a useful tool in the trace screening of GM crops. Moreover, this design concept can be extended to other proteins by simply changing the antibody.

Final Health and Environmental Risk Assessment of Genetically Modified Soybean A5547-127

Soybean A5547-127 expresses the phosphinothricin - N - acetyltransferase (pat) gene from the soil bacterium Streptomyces viridochromogenes. The encoded PAT protein confers tolerance to the active herbicidal substance glufosinate-ammonium. Bioinformatics analyses of the inserted DNA and flanking sequences in soybean A5547-127 have not indicated a potential production of putative harmful proteins or polypeptides caused by the genetic modification. Genomic stability of the functional insert and consistent expression of the pat gene have been shown over several generations of soybean A5547-127. With the exception of the intended changes caused by the trans-genetically introduced trait, data from field trials performed in the USA show that soybean A5547-127 is compositionally, morphologically and agronomically equivalent to its conventional counterpart and other commercial soybean varieties. A repeated dose toxicity study with rats and a nutritional assessment trial with broilers have not revealed adverse effects of soybean A5547-127. These studies indicate that soybean A5547-127 is nutritionally equivalent to and as safe as conventional soybean varieties. The PAT protein produced in soybean A5547-127 does not show sequence resemblance to known toxins or IgE-dependent allergens, nor has it been reported to cause IgE-mediated allergic reactions. Soybean is not cultivated in Norway, and there are no crosscompatible wild or weedy relatives of soybean in Europe. Based on current knowledge the VKM GMO Panel concludes that with the intended usage, there are no discernible safety concerns associated with soybean A5547-127 regarding human or animal health or to the environment in Norway.

Final Health and Environmental Risk Assessment of Genetically Modified Soybean A2704-12

Soybean A2704-12 expresses the phosphinothricin-N-acetyltransferase (pat) gene, from the soil bacterium Streptomyces viridochromogenes. The encoded PAT protein confers tolerance to the active herbicidal substance glufosinate-ammonium. Bioinformatics analyses of the inserted DNA and flanking sequences in soybean A2704-12 have not indicated a potential production of putative harmful proteins or polypeptides caused by the genetic modification. Genomic stability of the functional insert and consistent expression of the pat gene have been shown over several generations of soybean A2704-12. With the exception of the intended changes caused by the transgenetically introduced trait, data from field trials performed in the USA and Canada show that soybean A2704-12 is compositionally, morphologically and agronomically equivalent to its conventional counterpart and to other commercial soybean varieties. A repeated dose toxicity study in with rats and a nutritional assessment trial with broilers indicate that soybean A2704-12 is nutritionally equivalent to and as safe as conventional soybean varieties. The PAT protein produced in soybean A270412 does not show sequence resemblance to known toxins or IgE-dependent allergens, nor has it been reported to cause IgE-mediated allergic reactions. Soybean is not cultivated in Norway, and there are no cross-compatible wild or weedy relatives of soybean in Europe. Based on current knowledge, the VKM GMO Panel concludes that with the intended usage, there are no discernible safety concerns associated with soybean A2704-12 regarding human or animal health or to the environment in Norway.

DHHC-7 and -21 are palmitoylacyltransferases for sex steroid receptors

Classical estrogen, progesterone, and androgen receptors (ERs, PRs, and ARs) localize outside the nucleus at the plasma membrane of target cells. From the membrane, the receptors signal to activate kinase cascades that are essential for the modulation of transcription and nongenomic functions in many target cells. ER, PR, and AR trafficking to the membrane requires receptor palmitoylation by palmitoylacyltransferase (PAT) protein(s). However, the identity of the steroid receptor PAT(s) is unknown. We identified the DHHC-7 and -21 proteins as conserved PATs for the sex steroid receptors. From DHHC-7 and -21 knockdown studies, the PATs are required for endogenous ER, PR, and AR palmitoylation, membrane trafficking, and rapid signal transduction in cancer cells. Thus the DHHC-7 and -21 proteins are novel targets to selectively inhibit membrane sex steroid receptor localization and function.