Detection of secondary biomarker of met-eGH as a strategy to screen for somatotropin misuse in horseracing

Since the Australian commercialisation of the recombinant equine growth hormone (reGH) in 1998 (EquiGen-5), Bresagen), this reGH, which differs only from eGH by an additional methionine at the N-terminal end (met-eGH), is worldwide suspected to be administered to racehorses as a doping agent. Indeed, the use of this biological drug is considered as a threat to horseracing since it acts both on growth, development or reproductive functions, and on the improvement of performances. In this work, we describe two reliable techniques based on surface plasmon resonance biosensor immunoassay (SPR-BIA) and solid-phase enzyme-linked immunosorbent assay (ELISA) as new, rapid and efficient long-term screening methods applicable to horseracing antidoping analysis. The ELISA and SPR-BIA tests were applied to octanoic acid purified IgGs from serum/plasma samples collected on two thoroughbreds treated with recombinant equine growth hormone for a period of two weeks. The first kinetic study of serum/plasma antibodies raised as a consequence of recombinant equine growth hormone administrations, which allows the detection from eight days up to 200 days after the beginning of the treatment, was performed. In order to trace the occurrence of anti-reGH antibodies in routine analysis and to monitor the animal level exposure to this forbidden molecule, a random population study was conducted on 233 post-race horses.     

Imaging mass spectrometry using peptide isoelectric focusing

Imaging Mass Spectrometry (IMS) has emerged as a powerful technique in the field of proteomics. The use of Immobilized pH Gradient-IsoElectric Focusing (IPG-IEF) is also a new trend, as the first dimension of separation, in shotgun proteomics. We report a combination of these two outstanding technologies. This approach is based on the separation of shotgun-produced peptides by IPG-IEF. The peptides are then transferred by capillarity to a capture membrane, which is then scanned by the mass spectrometer to generate MS images. This high-throughput methodology allows a preview of the sample to be obtained in a single day. We report the application of this new pipeline for differential comparison of the membrane proteome of two different strains of Staphylococcus aureus bacteria in a proof-of-principle experiment.     

Cluster analysis of local convergent sequences of structures

The cluster analysis of very large objects is an important problem, which spans several theoretical as well as applied branches of mathematics and computer science. Here we suggest a novel approach: under assumption of local convergence of a sequence of finite structures we derive an asymptotic clustering. This is achieved by a blend of analytic and geometric techniques, and particularly by a new interpretation of the authors' representation theorem for limits of local convergent sequences, which serves as a guidance for the whole process. Our study may be seen as an effort to describe connectivity structure at the limit (without having a defined explicit limit structure) and to pull this connectivity structure back to the finite structures in the sequence in a continuous way. © 2017 Wiley Periodicals, Inc. Random Struct. Alg., 51, 674–728, 2017     

Flexible oligomer spacers as the key to solid-state photopolymerization of hydrogel precursors

Efficient crosslinking of conventional photoreactive hydrogel precursors relies on the mobility of the reactive groups and is typically addressed from the liquid state. However, this represents a major limitation for many processing techniques of hydrogel materials. Herein, a model precursor is introduced that overcomes this challenge using a prepolymer designed to enable successful crosslinking in the solid state. The precursor is synthesized by connecting a flexible, mono-acrylated spacer to a semi-crystalline hydrophilic backbone polymer using a di-isocyanate linker. The resulting prepolymers exhibit excellent solid-state photoreactivity, even in the absence of a photo-initiator. As a proof of concept, the precursor has successfully been processed by: (1) solution electrospinning with subsequent solid-state photopolymerization (SSPP), (2) melt-based additive manufacturing with subsequent SSPP and (3) two-photon polymerization in the solid state. No cell adhesion takes place on bare crosslinked 3D-printed scaffolds whereas excellent cell adhesion is recovered after application of a gelatin methacrylamide coating. With this novel class of UV-reactive precursors unprecedented hydrogel processing avenues are opened.     

Intrinsic Rate Constants ket of Photoinduced Electron Transfer between Anthracene Derivatives and Aromatic Donors: Does the Intersecting‐State Model Challenge Marcus Theory When Confronted with an Archetypal Set of Data?

Intrinsic photoinduced electron transfer (PET) rate constants k_et, resorting to classically studied acceptor‐donor couples, are confronted to two theoretical models of electron transfer. At a very exergonic driving force, k_et remains on a plateau value centered around 10¹¹ s⁻¹. It is shown that the well‐known and widely used Marcus theory fails to account for the data located on this plateau. On the contrary, the basically different approach of the intersecting‐state model (ISM) allows fitting the whole set of data with physically realistic parameters. The possibility is discussed that this success of the ISM over the Marcus model may give hints to explain the lack of an inverted region in forward PET in solution.     

Desymmetrization of meso‐N‐Sulfonylaziridines with Chiral Nonracemic Nucleophiles and Bases

The cyclohexene‐derived aziridine 7‐tosyl‐7‐azabicyclo[4.1.0]heptane ( 1 ) reacts with Grignard reagents in the presence of chiral nonracemic Cu‐catalysts to afford sulfonamides 3a – e (Scheme 3) in up to 91% ee under optimized conditions (Table 2). No activation of the aziridine by Lewis acids is required. The reaction may be extended to other bicyclic N‐sulfonylated aziridines, but aziridines derived from acyclic olefins, cyclooctene, and trinorbornene are unreactive under standard conditions (Scheme 5). Exposure of 1 to s‐BuLi in the presence of (−)‐sparteine (2.8 equiv.) affords the allylic sulfonamide 31 in 35% yield and 39% ee (Scheme 6). Under the same conditions, the aziridines 33 and 35 yield products 34 and 36 derived from intramolecular carbenoid insertion with 75 and 43% ee, respectively.     

Theory of Multiple‐Detection Size‐Exclusion Chromatography of Complex Branched Polymers

SEC separates complex branched polymers by hydrodynamic volume, rather than by molecular weight or branching characteristics. Equations relating the response of different types of detectors are derived including band broadening, by defining a distribution function N′(M,V_h), the number of chains with molecular weight M and hydrodynamic volume V_h. While the true molecular weight distribution of complex polymers cannot be determined by SEC, irrespective of the detector used, the formalism enables multiple detection SEC data to be processed to both analyze the polymer sample and reveal mechanistic information about polymer synthesis. The formalism also shows how the true weight‐ and number‐average molecular weight, and , can be obtained from correct processing of the hydrodynamic volume distributions.

     

Disorder Effects in “Plastic” and Highly Conducting Compounds of Poly(aniline)

Numerical methods of molecular dynamics have been combined to measurements of X-ray and neutron scattering in order to obtain a realistic view of structural and dynamical disorder properties of conducting compounds of so called “plastdoped” poly(aniline)s. This combination allowed us to propose for the whole family of these compounds one generic model of a layered structure in which exist statistical fluctuations of the electronic density along the stacking direction of alternating molecular layers. The most part of the dynamics in the 10⁻¹³–10⁻⁹ s time range concerns the motions of protons borne by the flexible tails of doping counter-ions contained in the structure. We found that the molecular dynamics is characterized by both broad time and spatial distributions. These experimental facts coupled to those obtained with electrical conductivity measurements indicate that the high mobility of the counter-ion sublattice seems to be a prerequisite to promote a global metal like electronic behaviour of the polymer films.