Ionizing radiation including electron beam (eBeam) technology has been used as a quarantine measure around the world for transboundary shipment of agricultural products. Since the treatment goal of this technology is not to instantly kill insects but to cause them to be sterile, an apparent challenge is how to ensure that the agricultural commodities have been exposed to ionizing radiation if live insects are found. Because irradiation affects DNA synthesis and cell division, we investigated the feasibility of using flow cytometry detection of eBeam irradiation-induced ploidy change as a diagnostic tool. All eBeam-treated holometabolous insects tested including cowpea bruchid (Callosobruchus maculatus), corn earworm (Helicoverpa zea) and fruit fly (Drosophila melanogaster) displayed significantly higher proportions of polyploid cells than their respective unirradiated controls. However, such increased DNA ploidy was mostly absent in irradiated hemimetabolous sand field cricket (Gryllus firmus), green peach aphid (Myzus persicae) and potato/tomato psyllid (Bactericera cockerelli). Further studies with representative holometabolous insects revealed that the eBeam-triggered DNA endoreplicative response was strong in larvae, but became weaker as insects continued to develop into pupae and was even diminished in adults. Therefore, the flow cytometry-based method has the potential to be developed into a diagnostic tool to determine whether juvenile insects found on agricultural shipments, particularly those that undergo complete metamorphosis, have received irradiation as a quarantine treatment. This simple and rapid detection method could potentially resolve the dilemma that occurs in border control and domestic movement of plant material and products from areas under quarantine.

中文翻译：

---

电子束辐照诱导全代谢性小昆虫DNA内复制：基于快速流式细胞仪的诊断

包括电子束（eBeam）技术在内的电离辐射已被用作全球跨境运输农产品的检疫措施。由于该技术的治疗目标不是立即杀死昆虫，而是使它们无菌，因此一个明显的挑战是，如果发现活虫，如何确保农产品已暴露于电离辐射下。由于辐射会影响DNA合成和细胞分裂，因此我们研究了使用流式细胞仪检测eBeam辐射引起的倍性变化作为诊断工具的可行性。所有经过eBeam处理的全代谢昆虫均经过测试，包括cow豆bruchid（Callosobruchus maculatus），玉米ear（Helicoverpa zea）和果蝇（Drosophila melanogaster））显示的多倍体细胞比例明显高于其各自未辐照的对照。然而，这种增加的DNA倍性在辐照的半代谢沙田（（Gryllus firmus），绿桃蚜（Myzus persicae）和马铃薯/番茄木虱（Bactericera cockerelli）中几乎不存在。）。对具有代表性的整体代谢昆虫的进一步研究表明，eBeam触发的DNA内复制反应在幼虫中很强，但随着昆虫继续发展成p而变弱，甚至在成虫中也减弱了。因此，基于流式细胞术的方法有可能发展成为一种诊断工具，以确定在农业运输中发现的幼虫，特别是经历了完全变态的幼虫是否已接受了检疫处理。这种简单，快速的检测方法可以潜在地解决在边境控制以及来自检疫区的植物材料和产品的国内运输中出现的难题。