Gaudry Emmanuel, Blais Catherine, Maria Annick, Dauphin-Villemant Chantal
Institut de Recherche Criminelle de la Gendarmerie Nationale, 1 Boulevard Théophile Sueur, F-93111 Rosny-Sous-Bois Cedex, France.
Forensic Sci Int. 2006 Jun 27;160(1):27-34. doi: 10.1016/j.forsciint.2005.06.014. Epub 2005 Sep 23.
Protophormia terraenovae is a forensically important fly whose development time is studied by forensic entomologists to establish the time elapsed since death (post-mortem interval, PMI). Quantity and nature of ecdysteroid hormones present in P. terraenovae pupae were analysed in order to determine if they could be correlated to the age of pupae found on corpses and thereby could give information on the PMI. Ecdysteroid levels were quantified during the pupal-adult development of synchronised animals using enzyme immunoassay (EIA), a sensitive method allowing acurate quantification in one pupa. Two types of pupae were compared: "fresh" pupae, kept frozen until analysis and "experimentally dried" pupae, which were left for several weeks at ambient temperature. A peak of ecdysteroids was detected between 36 and 96 h after pupariation in fresh animals. It was not observed in "experimentally dried" pupae. High-pressure liquid chromatography (HPLC) analyses combined with EIA showed that 20-hydroxyecdysone (20E) was the major free ecdysteroid at various pupal ages. Enzymatic hydrolysis experiments revealed the presence of apolar conjugates at all ages tested. However, neither qualitative nor quantitative difference was detected between early and late pupae. This study gives precise information on the nature and quantity of ecdysteroids in the course of pupal development of a calliphorid fly. The limits of using ecdysteroid measurement as a tool in forensic entomology are discussed.
新陆原伏蝇是一种在法医学上具有重要意义的苍蝇，法医昆虫学家通过研究其发育时间来确定死亡后的时间间隔（PMI）。分析了新陆原伏蝇蛹中蜕皮甾体激素的含量和性质，以确定它们是否与在尸体上发现的蛹的年龄相关，从而提供有关PMI的信息。使用酶免疫分析（EIA）对同步化动物从蛹到成虫的发育过程中的蜕皮甾体水平进行了定量，这是一种能够对单个蛹进行准确量化的灵敏方法。比较了两种类型的蛹：“新鲜”蛹，冷冻保存至分析时；“实验干燥”蛹，在环境温度下放置数周。在新鲜动物化蛹后36至96小时之间检测到蜕皮甾体的峰值。在“实验干燥”蛹中未观察到该峰值。高压液相色谱（HPLC）分析结合EIA表明，20-羟基蜕皮酮（20E）是不同蛹龄时主要的游离蜕皮甾体。酶促水解实验表明，在所有测试的蛹龄中均存在非极性结合物。然而，在早期和晚期蛹之间未检测到定性或定量差异。本研究提供了关于丽蝇蛹发育过程中蜕皮甾体的性质和含量的精确信息。讨论了将蜕皮甾体测量用作法医昆虫学工具的局限性。
