Application of Sarcosaprophagous Insects to Estimate the Postmortem Interval in 11 Cases.

ABSTRACT: Objective To test the feasibility and accuracy of with sarcosaprophagous insects postmortem interval （PMI） estimation with sarcosaprophagous insects and provide references for estimation practice. Methods Eleven cases confirmed by the detection results, with complete entomological evidence were selected. The insect species, estimation results and true results involved in the cases were statistically analyzed and compared. Results Thirteen species of insects were found at the criminal scene, including Chrysomya megacephala （Fabricius）, Chrysomya rufifacies （Macquart）, Chrysomya nigripes （Aubertin）, Lucilia sericata （Meigen）, Hydrotaea spinigera Stein, Muscina stabulans （Fallén）, Sarcophagid （species were not identified）, Megaselia scalaris （Loew）, Hermetia illucens （Linnaeus）, Saprinus splendens （Paykull）, Creophilus maxillosus （Linnaeus）, Dermestes maculatus （De Geer） and Necrobia ruficollis （Fabricius）. The PMI of all eleven cases was within the range of estimated PMI. The estimated results of 72.73% cases were on the same day of the true results. Conclusion Sarcosaprophagous insects can estimate the PMI simply and conveniently. In cases where the PMI is within the time range of one generation of flies or beetles, the estimation results are relatively accurate. However, the estimation is less accurate when the PMI is beyond the time range.

The correlation between neurotoxicity, aggregative ability and secondary structure studied by sequence truncated Abeta peptides.

Aggregated beta-amyloid (Abeta) peptides are neurotoxic and cause neuronal death both in vitro and in vivo. Although the formation of a beta-sheet structure is usual required to form aggregates, the relationship between neurotoxicity and the Abeta sequence remains unclear. To explore the correlation between Abeta sequence, secondary structure, aggregative ability, and neurotoxicity, we utilized both full-length and fragment-truncated Abeta peptides. Using a combination of spectroscopic and cellular techniques, we demonstrated that neurotoxicity and aggregative ability are correlated while the relationship between these characteristics and secondary structure is not significant. The hydrophobic C-terminus, particularly the amino acids of 17-21, 25-35, and 41-42, is the main region responsible for neurotoxicity and aggregation. Deleting residues 17-21, 25-35 or 41-42 significantly reduced the toxicity. On the other hand, truncation of the peptides at either residues 22-24 or residues 36-40 had little effect on toxicity and aggregative ability. While the N-terminal residues 1-16 may not play a major role in neurotoxicity and aggregation, a lack of N-terminal fragment Abeta peptide, (e.g. Abeta17-35), does not display the neurotoxicity of either full-length or 17-21, 25-35 truncated Abeta peptides.