Paired stable carbon and oxygen isotope analyses of human enamel for forensic human geolocation: An exploratory study.

Stable carbon isotope analysis has proven utility for reconstructing dietary information in humans in past populations. The usefulness of stable carbon for forensic geolocation has been little investigated, largely because of the globalization of the human diet seemingly rendering it inconsequential. This study queried this assumption at a country-wide level on a known sample group.

The application of a CART model for forensic human geolocation using stable hydrogen and oxygen isotopes.

The utility of stable hydrogen and oxygen isotope analysis of human tissues for geolocation is an important area of study within forensic science. This study aimed to first validate the latitudinal relationship between stable hydrogen and oxygen isotopes in drinking water and human keratinous tissues through the analysis of human samples with known geographical origin. And secondly, to explore the use of classification and regression tree (CART) models to geographically classify individuals based on the stable isotope values of tissues themselves.

Assessing the predictability of existing water-to-enamel geolocation models against known human teeth.

Stable isotope analysis of human tissues has become a valuable tool for mapping human geolocation. This study adds to the existing knowledge of the relationship between oxygen stable isotopes in human enamel and drinking water by presenting enamel oxygen values in clinic-extracted human dental enamel with known provenance. The results from this study indicate that the theoretical isotopic relationship between enamel and drinking water oxygen is weak at the city and country-level.

Histidine-Mediated Intramolecular Electrostatic Repulsion for Controlling pH-Dependent Protein-Protein Interaction.

Protein-protein interactions that can be controlled by environmental triggers have immense potential in various biological and industrial applications. In the current study, we aimed to engineer a pH-dependent protein-protein interaction that employs intramolecular electrostatic repulsion through a structure-guided histidine substitution approach. We implemented this strategy on protein G, an affinity ligand for immunoglobulin G, and showed that even a single point mutation effectively improved the pH sensitivity of the binding interactions without adversely affecting its structural stability or its innate binding function.

Assessing dual hair sampling for isotopic studies of grizzly bears.

Rationale: The stable isotope ratios of carbon (δ C values), nitrogen (δ N values) and sulfur (δ S values) in bear hair can be used to obtain information on dietary history. Sample protocols often require hair sampling from multiple anatomical locations; however, there remains a question as to whether this is necessary for isotopic studies of hair. The purpose of this study was to determine whether significant differences can be observed for the δ C, δ N and δ S values between paired hair samples taken from the rump and shoulder of grizzly bears (Ursus arctos).

A City-wide Investigation of the Isotopic Distribution and Source of Tap Waters for Forensic Human Geolocation Ground-truthing.

Human geolocation is prefaced on the accuracy of the geographic precision of mapped isotopic values for drinking water. As most people live in cities, it becomes important to understand city water supplies and how the isotopic values uniquely reflect that city. This study investigated the isotopic distribution of δ H and δ O from sourced tap waters that were collected from across the Metro Vancouver (MV) area (n = 135).

Characterization of ergothionase from Burkholderia sp. HME13 and its application to enzymatic quantification of ergothioneine.

We identified ergothionase, which catalyzes conversion of ergothioneine to thiolurocanic acid and trimethylamine, in a newly isolated ergothioneine-utilizing strain, Burkholderia sp. HME13. The enzyme was purified and its N-terminal amino acid sequence was determined.