|Budget Amount *help
¥7,200,000 (Direct Cost : ¥7,200,000)
Fiscal Year 1996 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1995 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1994 : ¥5,500,000 (Direct Cost : ¥5,500,000)
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.