Development and validation of a liquid chromatography-triple quadrupole mass spectrometry method for the determination of isopeptide ε-(γ-glutamyl) lysine in human urine as biomarker for transglutaminase 2 cross-linked proteins.

Determination of the levels of protein cross-linking catalysed by the activity of transglutaminase 2 in various disease states has remained a significant challenge. The ability to quantify the isopeptide ε-(γ-glutamyl) lysine, which can form as a heterogeneous bond within or between proteins has significant analytical and clinical potential as a biomarker in biofluids such as human urine. Increased transglutaminase 2 activity is associated with a number of diseases, such as fibrosis.

Partially shielded enzymes capable of processing large protein substrates.

We report the first method of enzyme protection enabling the production of partially shielded enzymes capable of processing substrates as large as proteins. We show that partially shielded sortase retains its transpeptidase activity and can perform bioconjugation reactions on antibodies. Moreover, a partially shielded trypsin is shown to outperform its soluble counterpart in terms of proteolytic kinetics.

Surface Immobilization and Shielding of a Transaminase Enzyme for the Stereoselective Synthesis of Pharmaceutically Relevant Building Blocks.

Transaminases are enzymes capable of stereoselective reductive amination; they are of great interest in the production of chiral building blocks. However, the use of this class of enzymes in industrial processes is often hindered by their limited stability under operational conditions. Herein, we demonstrate that a transaminase enzyme from Aspergillus terreus can be immobilized at the surface of silica nanoparticles and protected in an organosilica shell of controlled thickness.

Engineering Nanosized Organosilica for Molecular Recognition and Biocatalysis Applications.

A series of synthetic nanomaterials capable of molecular recognition and/or biocatalysis have been produced by exploiting the self-sorting, self-assembly and polycondensation of organosilane building blocks around protein templates. The established methodology allows for the production of thin organosilica layers of controlled thickness, down to nanometer precision. Fully synthetic virus recognition materials have been shown to specifically bind their target virus down to picomolar concentrations.

A Biocatalytic Nanomaterial for the Label-Free Detection of Virus-Like Particles.

The design of nanomaterials that are capable of specific and sensitive biomolecular recognition is an on-going challenge in the chemical and biochemical sciences. A number of sophisticated artificial systems have been designed to specifically recognize a variety of targets. However, methods based on natural biomolecular detection systems using antibodies are often superior.

Enzyme Shielding in an Enzyme-thin and Soft Organosilica Layer.

The fragile nature of most enzymes is a major hindrance to their use in industrial processes. Herein, we describe a synthetic chemical strategy to produce hybrid organic/inorganic nanobiocatalysts; it exploits the self-assembly of silane building blocks at the surface of enzymes to grow an organosilica layer, of controlled thickness, that fully shields the enzyme. Remarkably, the enzyme triggers a rearrangement of this organosilica layer into a significantly soft structure.

A cyclodextrin-based polymer for sensing diclofenac in water.

An assay for the determination of diclofenac concentration, in the micromolar range in water, was developed. It is based on the use of a recently developed cyclodextrin-based polymer that possesses an inherent affinity for the target pharmaceutical. This competitive assay is exploiting the possibility to displace a fluorescent dye, adsorbed in the cyclodextrin-based polymer, by the target drug.

Virus-like particles as virus substitutes to design artificial virus-recognition nanomaterials.

Functional recognition imprints of virus-like particles, at the surface of silica particles, were generated following a strategy based on protein-templated polycondensation of organosilanes.

Combining chemical sequential extractions with 3D fluorescence spectroscopy to characterize sludge organic matter.

The design and management of anaerobic digestion of sewage sludge (SS) require a relevant characterisation of the sludge organic matter (OM). Methods currently used are time-consuming and often insufficiently informative. A new method combining chemical sequential extractions (CSE) with 3D fluorescence spectroscopy was developed to provide a relevant SS characterisation to assess both OM bioaccessibility and complexity which govern SS biodegradability.

International cross-validation of a BOD5 surrogate.

BOD5 dates back to 1912 when the Royal Commission decided to use the mean residence time of water in the rivers of England, 5 days, as a standard to measure the biochemical oxygen demand. Initially designed to protect the quality of river waters from extensive sewage discharge, the use of BOD5 has been quickly extended to waste water treatment plants (WWTPs) to monitor their efficiency on a daily basis. The measurement has been automatized but remains a tedious, time- and resource-consuming analysis.

Using fluorescence-based microplate assay to assess DOM-metal binding in reactive materials for treatment of acid mine drainage.

One potential drawback of compost-based passive bioreactors, which is a promising biotechnology for acid mine drainage (AMD) treatment, is the transport of dissolved organic matter (DOM)-metal complexes in surface waters. To address this problem, the objective of this study was to assess the maximum capacity of organic substrates to release soluble DOM-metal complexes in treated water. The reactivities of DOM in maple wood chips and sawdust, composted poultry manure, and leaf compost were quantified toward Cd2+, Ni2+, Fe2+, and Cu2+ using fluorescence quenching.

Solid-phase fluorescence spectroscopy to characterize organic wastes.

The production of solid organic waste (SOW) such as sewage sludge (SS) or municipal solid waste (MSW) has been continuously increasing in Europe since the beginning of the 1990'. Today, the European Union encourages the stabilization of these wastes using biologic processes such as anaerobic digestion and/or composting to produce bio-energy and organic fertilizers. However, the design and management of such biologic processes require knowledge about the quantity and quality of the organic matter (OM) contained in the SOW.

Organic matter as a potential complementary tool for delta(18)O data interpretation in heterogeneous aquifers.

Evaluating transit time by using delta(18)O seasonal variation is often difficult in a Mediterranean context due to the erratic rainfall signature added to the complexity of flow mixing. The present study aims to show that using organic matter can improve interpretations of the delta(18)O signal. The natural fluorescence of organic compounds and dissolved organic carbon (DOC) data were recorded in the underground low-noise laboratory, located within the catchment area of the Fontaine de Vaucluse karstic system, over a four-year period.

Discrimination of farm waste contamination by fluorescence spectroscopy coupled with multivariate analysis during a biodegradation study.

The persistence of potential tracers of dissolved organic matter (DOM) generated from farm waste-amended soil was investigated by fluorescence spectroscopy coupled with classification and regression tree (CART) and principal component analysis (PCA) during a short-term (8 days) to midterm (60 days) biodegradation study. Pig manure (PM), cow manure (CM), wheat straw (WS), and soil alone (SA) treatment inputs were used. Waste amendments were potential sources of higher DOM concentrations.

Alternative spectrofluorimetric determination of short-chain volatile fatty acids in aqueous samples.

This paper presents a simple, rapid, and accurate method suitable for on-site measurement of short-chain volatile fatty acids (SCFA) in various environmental samples. This fluorimetric method involves a derivatization step of SCFA with N-(1-naphthyl)ethylenediamine (EDAN) and allows determination of acetic, butyric, propionic, valeric, lactic, succinic, and p-hydroxybenzoic acids in approximatively 10 min. To evaluate specificity and accuracy of the method, both laboratory-made waters and real samples ranging from wastewater plant and river to soils and composts have been tested.

Dissolved organic matter fluorescence as a water-flow tracer in the tropical wetland of Pantanal of Nhecolândia, Brazil.

The Nhecolândia is a sub-region of the Brazilian Pantanal wetland, where saline and freshwater lakes coexist in close proximity. Measurements of dissolved organic carbon (DOC) content and analysis of fluorescence excitation-emission matrices (EEM) were conducted in an effort to characterize spatial variability in concentration and source of dissolved organic matter (DOM) and to further understand the hydrochemical functioning of this complex environment. Increasing pH under the influence of evaporation resulted in an increasing DOC solubility ranging from 50 to over 300 mgC L(-1) in surface water.

Modelling the dynamics of pentachlorophenol bioavailability in column experiments.

The aqueous-phase concentration of an organic pollutant found in a subsurface environment is often assumed to be its bioavailable concentration. However, the aqueous-phase concentration does not adequately reflect the dynamics of contaminant availability to microbes in flow-through systems. This paper assesses the effects of interacting processes such as sorption, biodegradation, and transport on contaminant bioavailability, and the fraction of the bioavailable contaminant that is taken up by microbes.