Hippocampal and Reticulo-Thalamic Parvalbumin Interneurons and Synaptic Re-Organization during Sleep Disorders in the Rat Models of Parkinson’s Disease Neuropathology

We investigated the alterations of hippocampal and reticulo-thalamic (RT) GABAergic parvalbumin (PV) interneurons and their synaptic re-organizations underlying the prodromal local sleep disorders in the distinct rat models of Parkinson’s disease (PD). We demonstrated for the first time that REM sleep is a predisposing state for the high-voltage sleep spindles (HVS) induction in all experimental models of PD, particularly during hippocampal REM sleep in the hemiparkinsonian models. There were the opposite underlying alterations of the hippocampal and RT GABAergic PV+ interneurons along with the distinct MAP2 and PSD-95 expressions. Whereas the PD cholinopathy enhanced the number of PV+ interneurons and suppressed the MAP2/PSD-95 expression, the hemiparkinsonism with PD cholinopathy reduced the number of PV+ interneurons and enhanced the MAP2/PSD-95 expression in the hippocampus. Whereas the PD cholinopathy did not alter PV+ interneurons but partially enhanced MAP2 and suppressed PSD-95 expression remotely in the RT, the hemiparkinsonism with PD cholinopathy reduced the PV+ interneurons, enhanced MAP2, and did not change PSD-95 expression remotely in the RT. Our study demonstrates for the first time an important regulatory role of the hippocampal and RT GABAergic PV+ interneurons and the synaptic protein dynamic alterations in the distinct rat models of PD neuropathology.     

The influence of polycaprolactone content on the surface properties of polyurethane networks

The aim of this work was to examine the influence of polycaprolactone (PCL) as a soft segment (SS) on the surface properties of polyurethane networks (PUNs). Five PUNs with different SS content (from 10 to 50 wt%) were prepared using Boltorn® aliphatic hyperbranched polyester of the second pseudo generation and isophorone diisocyanate as components of hard segments. The structure, hydrophobicity, wettability, and swelling behavior of these PUNs were investigated. Primarily, the obtained results showed that properties of prepared PUNs strongly depend on the content of SS that is, PCL. It has been established that the increase of SS content reduced the degree of hydrogen bonding in PUNs. Also, the increase of the SS content in PUNs induced appearance of more pronounced microphase separated morphology, better hydrophobicity and non-wetting with diiodomethane. Simultaneously, the increase of the SS content led to the decrease of contact angles with formamide, and surface free energy of the prepared PUNs. These PUNs show good surface properties that are required for their potential application such as coatings.     

Gephyrin-Lacking PV Synapses on Neocortical Pyramidal Neurons

Gephyrin has long been thought of as a master regulator for inhibitory synapses, acting as a scaffold to organize γ-aminobutyric acid type A receptors (GABA_ARs) at the post-synaptic density. Accordingly, gephyrin immunostaining has been used as an indicator of inhibitory synapses; despite this, the pan-synaptic localization of gephyrin to specific classes of inhibitory synapses has not been demonstrated. Genetically encoded fibronectin intrabodies generated with mRNA display (FingRs) against gephyrin (Gephyrin.FingR) reliably label endogenous gephyrin, and can be tagged with fluorophores for comprehensive synaptic quantitation and monitoring. Here we investigated input- and target-specific localization of gephyrin at a defined class of inhibitory synapse, using Gephyrin.FingR proteins tagged with EGFP in brain tissue from transgenic mice. Parvalbumin-expressing (PV) neuron presynaptic boutons labeled using Cre- dependent synaptophysin-tdTomato were aligned with postsynaptic Gephyrin.FingR puncta. We discovered that more than one-third of PV boutons adjacent to neocortical pyramidal (Pyr) cell somas lack postsynaptic gephyrin labeling. This finding was confirmed using correlative fluorescence and electron microscopy. Our findings suggest some inhibitory synapses may lack gephyrin. Gephyrin-lacking synapses may play an important role in dynamically regulating cell activity under different physiological conditions.     

MALDI Q-TOF CID MS for Diagnostic Ion Screening of Human Milk Oligosaccharide Samples

Human milk oligosaccharides (HMO) represent the bioactive components of human milk, influencing the infant’s gastrointestinal microflora and immune system. Structurally, they represent a highly complex class of analyte, where the main core oligosaccharide structures are built from galactose and N-acetylglucosamine, linked by 1–3 or 1–4 glycosidic linkages and potentially modified with fucose and sialic acid residues. The core structures can be linear or branched. Additional structural complexity in samples can be induced by endogenous exoglycosidase activity or chemical procedures during the sample preparation. Here, we show that using matrix-assisted laser desorption/ionization (MALDI) quadrupole-time-of-flight (Q-TOF) collision-induced dissociation (CID) as a fast screening method, diagnostic structural information about single oligosaccharide components present in a complex mixture can be obtained. According to sequencing data on 14 out of 22 parent ions detected in a single high molecular weight oligosaccharide chromatographic fraction, 20 different oligosaccharide structure types, corresponding to over 30 isomeric oligosaccharide structures and over 100 possible HMO isomers when biosynthetic linkage variations were taken into account, were postulated. For MS/MS data analysis, we used the de novo sequencing approach using diagnostic ion analysis on reduced oligosaccharides by following known biosynthetic rules. Using this approach, de novo characterization has been achieved also for the structures, which could not have been predicted.     

Experimental investigation and thermodynamic prediction of the Bi–Sb–Zn phase diagram

Phase diagram of the ternary Bi–Sb–Zn system was investigated experimentally by DTA and SEM-EDS methods and analytically by CALPHAD method. The liquidus projection, invariant equilibria, several vertical sections and isothermal section at 300 °C were predicted using COST 531 thermodynamic database. Phase transition temperatures of alloys along three predicted vertical sections of the Bi–Sb–Zn ternary system with molar ratio Bi:Sb = 1, Bi:Zn = 1 and Sb:Zn = 1, were measured by differential thermal analysis (DTA). Predicted isothermal section at 300 °C was compared with the results of the scanning electron microscope (SEM) with energy dispersive spectrometry (EDS) analysis from this work.     

Pentaerythritol crystallization – Influence of the process conditions on the granulometric properties of crystals

The quality of crystals depends on many factors that determine their granulometric properties. In order to obtain crystals of desired size distribution, proper selection of the operating conditions is of a great importance. Commonly, the unseeded cooling crystallization is controlled by selecting the appropriate cooling profile. The crystallization process can also be controlled by adding a certain number of seed crystals of a uniform size in the crystallizer at the saturation temperature. This paper investigates the influence of the process conditions (mixing intensity, cooling profile, batch time, saturation temperature and seeding) on the granulometric properties of pentaerythritol obtained by batch cooling crystallization. All investigated process conditions influence the crystal size distribution (seeded and unseeded experiments). On the other hand, the shape of crystals was the same for all experimental conditions. Optimal cooling profile, lower retention time, higher mixing rate, and smaller initial seed surface area improves the final crystal size distribution.     

Analysis of noncovalent chitinase-chito-oligosaccharide complexes by infrared-matrix assisted laser desorption ionization and nanoelectrospray ionization mass spectrometry

Transferring noncovalently bound complexes from the condensed phase into the gas phase represents a challenging task due to weak intermolecular bonds that have to be maintained during the phase transition. Currently, electrospray ionization (ESI) is the standard mass spectrometric (MS) technique to analyze noncovalent complexes. Although infrared matrix-assisted laser desorption ionization (IR-MALDI)-MS also provides particular soft desorption/ionization conditions, this method has so far hardly been applied for the analysis of noncovalent complexes. In this study, we employed IR-MALDI orthogonal time-of-flight (o-TOF)-MS in combination with the liquid matrix glycerol to characterize the specific complex formation of chito-oligosaccharide (CHOS) ligands with two variants of Chitinase A (ChiA) from Serratia marcescens, the inactive E315Q mutant and the active W167A mutant, respectively. The IR-MALDI-o-TOF-MS results were compared to those obtained using nano-ESI-quadrupole (q)-TOF-MS and ultraviolet (UV)-MALDI-o-TOF-MS. Using IR-MALDI-o-TOF-MS, specific noncovalent complexes between ChiA and CHOS were detected with distributions between enzymes with bound oligosaccharides vs free enzymes that were essentially identical to those obtained by nano-ESI-q-TOF-MS. Chitinase-CHOS complexes were not detected when UV-MALDI was employed for desorption/ionization. The results show that IR-MALDI-MS can be a valuable tool for fast and simple screening of noncovalent enzyme-ligand interactions.     

Synthesis of some fumaric acid polyamides from active diester monomers

Summary The solution polycondensation of two active diesters, bis(2,4-dinitrophenyl) fumarate and 1,1-(fumaroyldioxy)bis(benzotriazole), with a series of alphatic and aromatic diamines in N-methyl pyrolidone at room temperature, was investigated. The polycondensation reactions yielded a series of fumaric acids polyamides. The polymers obtained from aliphatic diamines were soluble in trifluroacetic acid and exhibited well-defined melting points. The polymers obtained from aromatic diamines are infusible at temperatures below 300°C but were thermally stable and soluble in dimethylacetamide containing 4% LiC1.     

Synthesis and rheological study of some maleic acid and fumaric acid stereoregular polyesters

Summary First unsaturated polyester fibers were prepared starting from stereoregular, macromolecular poly(octamethylene fumarate). Fibers obtained from octamethylene copolyesters of fumaric and terephthalic acids manifested improved mechanical properties and higher melting points. All unsaturated polyester fibers prepared in the study, based on the homopolymer and on copolymers of fumaric acid, even those containing as low as 10% of fumaric acid residues, are able to be covalently bonded to an unsaturated polyester matrix.For part 7, see Jaovi M.S., et al., Makromol. Chem. (submitted)     

Influence of NaCl on Granulometric Characteristics and Polymorphism in Batch‐Cooling Crystallization of Glycine

The effect of NaCl added in different quantities on thermodynamic properties, granulometric characteristics, and structure of glycine in a crystallization process was investigated. Solubilities of α‐ and γ‐polymorphs in the presence of varying amounts of NaCl were analyzed. In order to examine the impact of the additive on granulometric properties of glycine, crystal morphology was examined by observing crystals under a scanning electron microscope. Crystal size distribution was determined by sieve analysis. By X‐ray diffraction analysis, the critical concentration of NaCl at which the structure of glycine changed, could be defined. The purity of obtained polymorphs was confirmed by Fourier transform infrared spectroscopy.