抄録
Regarding the case of a homicide and abandoning of a corpse, we tried to carry out various inspections for the bloodstain on the T-shirt, which was worn by the adipocere corpse that had been buried for about one month in the ground. In spite of having the smell and color tone of decomposition, the blood type of the sample by the absorption-elution test and DNA type inspection (MCT118 and nine kinds of STR) could be determined. However, the determination for human blood inspection, in which hemoglobin had been targeted as an index, failed. Considering the color tone and bad smell, this bloodstain was thought to be polluted by certain bacteria. Thus, we tried to isolate them and succeeded in getting two kinds of bacteria, A and B from this bloodstain. PCR amplification of 16SrRNA gene (16SrDNA) was performed using universal primer sets for general bacteria. Both sequences of the amplified fragments showed high similarities to Bacillus sp.. Next, isolated Bacillus sp. cultured in the medium with human hemoglobin and its serological stability was monitored. The result showed that these Bacillus sp. decomposed human hemoglobin quickly. The remarkable degradation of DNA was not observed and the influence of Bacillus sp. on DNA stability was checked. It was found that the bloodstain was positive to genetic inspection of amelogenine gene, another index for human and beast judgment, although the bloodstain was negative to serological inspection of human blood.
As a conclusion we propose a slight improvement of human blood inspection process: when blood sample has been possibly contaminated by bacteria by having been buried in the ground for a long time, total judgment of human blood identification should be included, in addition to serological inspection.
