Identification of Primary Organophosphate Esters Contributing to Enhanced Risk of Gestational Diabetes Mellitus Based on a Case-Control Study.

Epidemiological studies on associations of organophosphate ester (OPE) exposure and gestational diabetes mellitus (GDM) risk, which remain rare and inconclusive, were carried out with a case-control population comprising 287 GDM and 313 non-GDM pregnant women recruited from Tianjin. The GDM group suffered distinctly higher serum concentrations of tri-n-butyl phosphate (TNBP), tri(2-butoxyethyl) phosphate (TBOEP), triphenyl phosphate (TPHP), tri-iso-propyl phosphate (TIPP), and tri(1-chloro-2-propyl) phosphate (TCIPP) than the healthy control group (p < 0.001). Traditional analysis methods employed for either individual or mixture effects found positive correlations (p < 0.05) between the concentrations of five OPEs (i.e., TNBP, TBOEP, TPHP, TIPP, and TCIPP) and the incidence of GDM, while 2-ethylhexyl diphenyl phosphate, tri(1-chloro-2-propyl) phosphate, and bis(2-ethylhexyl) phosphate exhibited opposite effects. Three machine learning methods considering the concurrence of OPE mixture exposure and population characteristics were applied to clarify their relative importance to GDM risk, among which random forest performed the best. Several OPEs, particularly TNBP and TBOEP ranking at the top, made greater contributions than some demographical characteristics, such as prepregnancy body mass index and family history of diabetes, to the occurrence of GDM. This was further validated by another independent case-control population obtained from Hangzhou.

Structure-Related Thyroid Disrupting Effect of Perfluorooctanesulfonate-like Substances in Zebrafish Larvae.

Chlorinated polyfluorooctane ether sulfonate (6:2 Cl-PFESA), hydrogenated polyfluorooctane ether sulfonate (6:2 H-PFESA), and chlorinated polyfluorooctanesulfonate (Cl-PFOS) share structural similarities with the regulated perfluorooctanesulfonate (PFOS), but their toxic potential is rarely known. Here, the thyroid disrupting potential of these four compounds in zebrafish larvae has been comparably investigated. PFOS, Cl-PFOS, and 6:2 Cl-PFESA were accumulated in the larvae at similar levels, approximately 1.3-1.6 times higher than 6:2 H-PFESA. Additionally, PFOS, Cl-PFOS, and 6:2 Cl-PFESA exhibited stronger disruption than 6:2 H-PFESA on genetic regulation, particularly concerning thyroid hormone (TH) activation and action and on TH homeostasis in both free and total forms of thyroxine (T4) and 3,5,3'-triiodothyronine (T3). These results indicate that chlorination or oxygen insertion does not substantially alter the thyrotoxicity of PFOS, but hydrogenation mitigates it. Molecular docking analysis and the luciferase reporter gene assay provided mechanistic perspectives that the PFOS-like substances could competitively replace THs to bind with TH plasma and membrane transporters, thereby disrupting TH transport and action, respectively. Moreover, they are also potent to disrupt TH synthesis and activation through Na+/K+-dependent transport of I- or competitive binding to the sites of deiodinases.

A New "Mix and Measure" Method for Rapid Quantitative Determination of Alkalinity Based on Proton Equilibrium and Definite Integral of Buffer Capacity.

Alkalinity is crucial in environmental control of ecosystems, wastewater and drinking water treatment, and industrial process control. In this work, we reported a new equation for calculating alkalinity based on the definition of buffer capacity in acid-base buffer solutions and the quantitative relationship between the buffer capacity and pH changes. A "mix and measure" method was developed using this new equation, involving mixing a solution with unknown alkalinity and a standard solution in a specific volume ratio, followed by measuring the pH after mixing. The alkalinity of the solution can be calculated using the newly developed equation. The "mix and measure" method is much more efficient than traditional titration methods for determination of alkalinity because it is restricted by the titration stoichiometric point. Additionally, we demonstrated the rapid determination of the alkalinity for a series of solutions using a portable detection system. This system exhibited precision and accuracy comparable to those of traditional titration methods. The portable system offers great potential for the on-site and real-time determination of alkalinity for industrial control and environmental monitoring purposes.

Novel insights into the mediating roles of cluster of differentiation 36 in transmembrane transport and tissue partition of per- and polyfluoroalkyl substances in mice.

Transmembrane transport is important for bioaccumulation of per- and polyfluoroalkyl substances (PFASs) in organisms, but has not yet been well understood. Here, the roles of cluster of differentiation 36 (CD36) in accumulation of PFASs were investigated. CD36 was overexpressed in Escherichia coli to get CD36-BL21 strain, and the binding affinities of 20 PFASs with CD36 were determined by microscale thermophoresis, which grew up to 17.5 µM with increasing carbon chain length. Consequently, the accumulation of most PFASs was remarkably promoted in CD36-BL21 in comparison to the wild strain, and the enhancement was proportional to their binding affinities with CD36 (r = -0.96). However, this effect was depressed greatly as CD36 was inhibited by sulfo-N-succinimidyl oleate (SSO). Additionally, as the mice received SSO pretreatment before they were exposed to perfluorododecanoic acid, its accumulation in the tissues rich in CD36, such as liver, was suppressed, but increased by 1.1 times in the serum. These indicated that CD36 played critical roles in the transmembrane transport and tissue partition of PFASs in organisms. The developed relationship between liver-blood partition of PFASs and their binding affinities with intracellular proteins was distinctly improved by incorporating that with CD36 (r = -0.97).

Colorimetric detection of Hg2+ using gold nanoparticles synthesized by Trichosporon montevideense WIN.

OBJECTIVE: To investigate a simple, cost-effective and eco-friendly method for colorimetric detection of Hg2+ using gold nanoparticles (AuNPs) synthesized by Trichosporon montevideense WIN. RESULTS: Hg2+ induced more visible blue shift of SPR band of the AuNPs than other heavy metal ions including Pb2+, Cd2+, Fe3+, Mn2+, Co2+ and Cu2+. The λmax of SPR band exhibited a gradual blue shift from 548 to 537 nm with concentration of Hg2+ increasing (0-200 µM), and the absorbance ratio (A537/A548) showed a positive linear correlation with Hg2+ concentration (R2 = 0.96). AuNPs synthesized at pH 6 showed more obvious blue shift than at pH 5 and pH 7. Through Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM) analysis, biomolecules coated on the AuNPs were speculated to dominate the formation of a core (Au)-shell (Hg) structure, which resulted in the colorimetric response. CONCLUSION: A sensitive and selective approach to detect Hg2+ using AuNPs synthesized by Trichosporon montevideense WIN is reported for the first time, which can provide a new potential candidate for detecting Hg2+ in the future.