?-Amylase Kinetic Test in Bodily Single and Mixed Stains

Estimating the way of deposition of saliva stains using quantitative analysis of forensic salivary biomarkers

Analyzing the way of deposition of saliva stains contributes to appropriate interpretation of saliva as evidence in court, particularly in sexual assault cases. In this proof-of-concept study, we aimed to confirm the difference between drooling-derived (non-contact) saliva and licking-derived (contact) saliva and clarify whether objectively distinguishing between the two saliva is possible. To allow discrimination between these two samples, an indicator was devised where the relative Streptococcus salivarius DNA quantity was calculated by dividing the S. salivarius DNA copies by the amount of stained saliva from the same saliva sample using quantitative polymerase chain reaction and salivary α-amylase activity assays. The study findings reveal that the value of the proposed indicator of licking-derived saliva was 100-fold significantly greater than that of drooling-derived saliva (P < 0.05, Welch's t-test). However, theoretical and technical challenges preclude the application of this indicator as a practical method. We believe that this saliva-specific bacterial DNA-based approach could allow estimation of the saliva stain deposition method.

Simple and conveniently accessible bi-fluorescence-labeled substrates for amylases

Synthesis of bi-fluorescence-labeled maltooligosaccharides for amylase assay was accomplished. Preliminary biological evaluation of both bi-fluorescence-labeled maltohexasaccharide and maltose using alpha-amylase was carried out, and the hexaosyl derivative showed unique variation on the basis of fluorescence resonance energy transfer (FRET).