Species identification of Trichinella originated from various host and different geographical location by MALDI-TOF.

The foodborne zoonotic nematode Trichinella spp. can cause human trichinellosis when raw or undercooked contaminated meat is ingested. To date, twelve Trichinella species/genotypes have been described. According to EU regulation any Trichinella larvae detected during mandatory routine examinations need to be identified at a species level by a competent laboratory. Currently, Trichinella species identification is performed using molecular biology tools such as multiplex PCR, PCR-sequencing or PCR-RFLP. These techniques require high level of skills for good interpretation of the results. Due to its rapidness and ease of use a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) protocol was previously developed for the identification of Trichinella species. Using this method, spectra from different Trichinella species and strains were acquired allowing to generate new Main Spectra (MSP). Finally a new MSP database from Trichinella spp. Samples of different countries (France, Germany and Poland), including field samples, was generated. Comparing the different main spectra, Trichinella worms were identified at the species level and differences in the genetic diversities within the different species are discussed. In conclusion, using the previously described method on field samples is a reliable, rapid, easy-to-use and cheap tool for Trichinella species identification. The new Trichinella database could be incremented with new samples. It constitutes a tool, which could be used as an alternative method to replace the actual molecular methods for Trichinella species identification.

Evaluation of MALDI-TOF MS and an expanded custom reference spectra database for the identification and differentiation of Taylorella equigenitalis and Taylorella asinigenitalis.

Misidentification between Taylorella equigenitalis, the causative agent of contagious equine metritis (CEM), and Taylorella asinigenitalis is observed by the gold standard culture method. The performance of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) for Taylorella species identification was evaluated using 85 T. equigenitalis and 28 T. asinigenitalis strains selected on the basis of multilocus sequence typing data. Seven of the T. equigenitalis and 9 of the T. asinigenitalis strains were used to generate in-house reference spectra to expand the existing commercial Bruker database. Two bacterial incubation times and 3 different sample preparation procedures were compared. Overall, we demonstrated the usefulness of MALDI-TOF MS as a differential diagnostic tool for CEM; however, commercial spectra databases should be expanded with T. asinigenitalis reference spectra to achieve the expected performance. Moreover, direct spotting of 48-h colonies was not only the most efficient protocol but also the easiest to implement in a clinical setting.

Variations of anthropogenic gadolinium in rivers close to waste water treatment plant discharges.

Rare earth element (REE) concentrations were determined for 22 sites sampled during two water periods: high flow in winter and low flow in summer. Shale-normalized REE patterns of all samples displayed positive gadolinium (Gd) anomalies. They revealed a widespread contamination of anthropogenic Gd (Gdant) from waste water treatment plant (WWTP) outputs to catchment areas used for drinking water. No significant variations in Gdant were observed between the two flow water periods, but differences in the Gd anomalies were present. However, these differences seem to be associated rather with seasonal variations in the river flow rate than with the release of GdAnt from WWTPs. In proximity to WWTP discharges, strong GdAnt variations ranged from few nanograms per litre to more than 80 µg L-1 and rarely showed a repetitive pattern day after day during 14 days. These concentrations were diluted into the river stream and measured around 10 ng L-1 close to the catchment areas used for drinking water. A principal component analysis (PCA) using the GdAnt concentrations and some classical physicochemical parameters (pH, water temperature, total alkalinity (TA), total organic carbon (TOC), biochemical and chemical oxygen demand (BOD and COD), Cl-, NO3- and SO42-) allowed a site separation according to the level of Gd contamination, highlighting that the highest GdAnt concentrations were found in the north of the region Lorraine (France) where the population density is high and most of the MRI examinations are performed.

Chromium hazard and risk assessment: New insights from a detailed speciation study in a standard test medium.

Despite the consensus about the importance of chemical speciation in controlling the bioavailability and ecotoxicity of trace elements, detailed speciation studies during laboratory ecotoxicity testing remain scarce, contributing to uncertainty when extrapolating laboratory findings to real field situations in risk assessment. We characterized the speciation and ecotoxicological effects of chromium (CrIII and CrVI ) in the International Organization for Standardization (ISO) medium for algal ecotoxicity testing. Total and dissolved (< 0.22 µm) Cr concentrations showed little variability in media spiked with CrVI , whereas dissolved Cr concentration decreased by as much as 80% over a 72-h time period in medium amended with CrIII . Analyses by ion chromatography inductively coupled plasma mass spectrometry (IC-ICP-MS) highlighted the absence of redox interconversion between CrIII or CrVI both in the presence and absence of algal cells (Raphidocelis subcapitata). Furthermore, the concentration of ionic CrIII dropped below detection limits in less than 2 h with the corresponding formation of carbonate complexes and Cr hydroxides. Precipitation of CrIII in the form of colloidal particles of variable diameters was confirmed by nanoparticle (NP) tracking analysis, single particle ICP-MS, and single particle counting. In terms of time-weighted dissolved (< 0.22 µm) Cr concentration, CrIII was 4 to 10 times more toxic than CrVI . However, CrIII ecotoxicity could arise from interactions between free ionic CrIII and algae at the beginning of the test, from the presence of Cr-bearing NPs, or from a combination of the 2. Future ecotoxicological studies must pay more attention to Cr speciation to reliably compare the ecotoxicity of CrIII and CrVI . Environ Toxicol Chem 2018;37:983-992. © 2017 SETAC.

Bioaccumulation of gadolinium in freshwater bivalves.

In this study, the presence of anthropogenic gadolinium (Gd) was evaluated in rivers, close to wastewater treatment plant outputs. Then, one site was selected for in situ experiments to assess the bioaccumulation of Gd in the digestive gland and in the gills of two bivalves (Dreissena rostriformis bugensis and Corbicula fluminea). For both organisms, the results suggested that the bioaccumulation of Gd can be observed when organisms are exposed in a geogenic and anthropogenic Gd mixture. In order to observe if Gd can bioaccumulate in tissues of bivalves when the ion is only present as the main anthropogenic speciation of Gd, i.e., Gd-contrast agents (Gd-CAs), the gadoteric acid was used for a laboratory experiment. In this case, the presence of Gd was clearly detected in a significant amount in the digestive glands of D. rostriformis bugensis and C. fluminea while low concentrations are measured in the gills. For the first time, these results clearly showed that Gd can bioaccumulate in bivalve tissues even when it is only present as Gd-CAs. Biochemical activities were measured in the digestive gland and in the gills of the bivalves to assess the effects of Gd-CA bioaccumulation. No significant variations were observed in the gills. Concerning the digestive gland, after 7 days of exposure at 10 µg L-1 of Gd as Gd-CA speciation, GST activity in D. rostriformis bugensis and lipid hydroperoxide and mitochondrial electron transfer system in C. fluminea had increased. The results suggest an acclimation of the organisms to the presence of Gd-CAs in the medium within less than 21 days.