An importance of food allergen detection has been growing in food industry. Here, we developed a rapid and easy-to-use detection system for Ara h1, a major allergen in peanut, using gold nanoparticles and switchable linkers. The detection system was performed by two steps. In the first step, Ara h1 was mixed with various concentrations (0.2 - 1.0μg/mL) of biotinylated anti-Ara h1 antibody (i.e., switchable linker, SLs) solutions for 20 min. After mixing, streptavidin coated gold nanoparticle (Abs. 4.0) was added to the mixture solutions with agitation for10 min. Without Ara h1(control), the region of aggregation caused by quantitative relationship between SLs and gold nanoparticle was observed at more than 0.4 μg/mL of SLs. However, under presence of Ara h1, SLs covered with Ara h1 had less ability to react with gold nanoparticles than naked SLs. This resulted in a change of the quantitative relationship mentioned above, which led to shift of the aggregation region. When 10 nM and 40 nM of Ara h1 were added, the aggregation region was appeared from 0.5and 0.8 μg/mLof switchable linkers, respectively. Ara h1 in peanut sample was also detected with this system. 0.4 μg/mL of switchable linkers are mixed with serially diluted peanut extract solutions. As a result, the shift of the aggregation region was observed from undiluted extract to 10 -2 diluted solution. This system could be adapted to detect other harmful/useful bio materials in food.

Perennial ryegrass (Lolium perenne L.) is one of the most important grass species in the world's temperate zones. It is used as high-quality forage in pastures and for recreational use as turf in golf courses, lawns and parks. Genetic improvement of perennial ryegrass is difficult due to its self-incompatibility. Consequently, progress by conventional breeding can be slow. Genetic transformation is an alternative that permits direct introduction of useful genes into a plant's genome and is becoming a powerful tool to complement conventional breeding. To improve environmental stress tolerance and quality of perennial ryegrass by introducing better and useful genes into the genome, we have developed a rapid and efficient transformation system using Agrobacterium-mediated gene transfer system.