Detection of plankton by molecular biological method.

溺水死亡的诊断通常基于身体的外部检查和尸检以及实验室调查的结果。用化学消化法检测器官中的浮游生物是诊断溺死尸体的常规方法。在本研究中，我们尝试用分子生物学方法对蓝藻中聚球菌属的皮浮游生物（大约1 mum）的16S核糖体DNA （rDNA）进行PCR分析，以诊断溺水。我们设计了与已测序的浮游生物16S rDNA可变区域互补的引物。比较了3种皮浮游生物、5种其他蓝藻、Melosira（硅藻）、astasturum（绿藻）、Bikal湖细菌和人类的PCR产物。该引物特异性扩增了picoplankton模板DNA的picogram order。将微浮游生物模板与人肺组织混合时，至少需要10 ng的模板DNA才能获得PCR产物。从肺组织中分离出微浮游生物，使PCR的灵敏度提高了100倍以上。从福尔马林固定的溺水组织中获得了特异的浮游生物PCR产物。利用微浮游生物16S rDNA对溺水进行了分子生物学诊断。

A diagnosis of death by drowning is normally based on findings from the external examination of the body and autopsy together with laboratory investigations. The detection of planktons in organs using the chemical digestion method is routinely performed on cadavers for the diagnosis of drowning. In the present study, we attempted to use the molecular biological method for the diagnosis of drowning by PCR analysis of the 16S ribosomal DNA (rDNA) of picoplanktons, belonging to the Synechococcus genus in cyanobacteria (approximately 1 mum in size).We designed primers complementary to the variable regions of 16S rDNA of the picoplankton we had sequenced.A comparison was made of the PCR products from the three picoplanktons, five other cyanobacteria, Melosira (diatom), Staurasturum (green alga), bacteria from Lake Bikal, and humans. The picogram order of template DNA from picoplankton was specifically amplified by the primers. When the template of picoplankton was mixed with human lung tissue, at least 10 ng of template DNA was needed to obtain a PCR product. The isolation of the picoplankton from lung tissue increased sensitivity of PCR more than a hundred-fold. The specific PCR products of the picoplankton were obtained from formalin-fixed drowning tissue. Molecular biological diagnosis of drowning was successful using picoplankton 16S rDNA.