Combination of 3-O-Levulinoyl and 6-O-Trifluorobenzoyl Groups Ensures α-Selectivity in Glucosylations: Synthesis of the Oligosaccharides Related to Aspergillus fumigatus α-(1 → 3)-d-Glucan.

Stereospecific α-glucosylation of primary and secondary OH-group at carbohydrate acceptors is achieved using glucosyl N-phenyl-trifluoroacetimidate (PTFAI) donor protected with an electron-withdrawing 2,4,5-trifluorobenzoyl (TFB) group at O-6 and the participating levulinoyl (Lev) group at O-3. New factors have been revealed that might explain α-stereoselectivity in the case of TFB and pentafluorobenzoyl (PFB) groups at O-6. They are of conformational nature and confirmed by DFT calculations. The potential of this donor, as well as the orthogonality of TFB and Lev protecting groups, is showcased by the synthesis of α-(1 → 3)-linked pentaglucoside corresponding to Aspergillus fumigatus α-(1 → 3)-d-glucan and of its hexasaccharide derivative, bearing ß-glucosamine residue at the non-reducing end.

Mathematical modeling of the Fontan blood circulation supported with pediatric ventricular assist device.

The decompensated univentricular circulation is identified as one of the most challenging conditions and the application of the mechanical circulatory support (MCS) devices is proposed as therapeutic option for Fontan failure. Modelling methodologies are reported to identify the optimized types, extent and duration of required hemodynamic support using MCS. The specific parameters of device-body interaction during support of failing Fontan circulation within the design points of dedicated pediatric ventricular assist devices has not been previously defined. In this work, we introduce a mathematical model developed to simulate the interaction between the Fontan single-ventricular circulation and a constant-flow pediatric ventricular assist device (VAD) Sputnik. The interaction is studied at a pump rotor speed of 5000-9000 rpm. This simulation demonstrates that the pump replacing pulmonary ventricle of the heart creates necessary pressure differential between the systemic veins (7 mmHg) and the pulmonary artery (17.3 mmHg). Moreover, it increases the venous return that, according to the Frank-Starling mechanism, increases the stroke volume up to 32 ml/bpm (26 ml/bpm - without using a pump). For the first time, a simulation for the pediatric VAD Sputnik has been carried out. The simulation results confirm pediatric VAD Sputnik can be a possible tool to normalize the Fontan circulation in pediatric patients.

Quality Control of Heparin Injections: Comparison of Four Established Methods.

Heparin is an anticoagulant medication that is usually injected subcutaneously. The quality of a set of commercial heparin injections from different producers was examined by NMR, IR, UV-Vis spectroscopies and potentiometric multisensor system. The type of raw material regarding heparin animal origin and producer, heparin molecular weight and activity values were derived based on the non-targeted analysis of 1H NMR fingerprints. DOSY NMR spectroscopy was additionally used to study homogeneity and additives profile. UV-Vis and IR, being cheaper than NMR, combined with multivariate statistics were successfully applied to study excipients composition as well as semi-estimation of activity values. Potentiometric multisensor measurements were found to be an important additional source of information about inorganic composition of finished heparin formulations. All investigated instrumental techniques are useful for finished heparin injections and should be selected according to availability as well as the information and confidence required for a specific sample.

Distinguishing paracetamol formulations: Comparison of potentiometric "Electronic Tongue" with established analytical techniques.

Fast and inexpensive analytical tools for identification of the origin of pharmaceutical formulations are important to ensure consumers safety. This study explores the potential of potentiometric multisensor systems ("electronic tongues") in this type of application. 72 paracetamol samples purchased in different countries and produced by various companies were studied via infrared spectroscopy (IR), near infrared spectroscopy (NIR), nuclear magnetic resonance spectroscopy (NMR) and multisensor system (ET). A variety of chemometric tools was applied to explore and compare the information yielded by these methods. It was found that ET is capable of distinguishing paracetamol formulations from different producers. The chemical information derived from potentiometric sensor responses has something in common with that derived from NIR and IR; however, it is orthogonal to that from NMR. ET can be a valuable tool in express quality assessment of drugs.

Properties of a recombinant GH49 family dextranase heterologously expressed in two recipient strains of Penicillium species.

The dexA gene encoding Penicillium funiculosum dextranase (GenBank accession MH581385) belonging to family 49 of glycoside hydrolases (GH49) was cloned and heterologously expressed in two recipient strains, P. canescens RN3-11-7 and P. verruculosum B1-537. Crude enzyme preparations with the recombinant dextranase content of 8-36% of the total secreted protein were obtained on the basis of new Penicillium strains. Both recombinant forms of the dextranase were isolated in a homogeneous state using chromatographic techniques. The purified enzymes displayed very similar properties, that is, pI 4.55, activity optima at pH 4.5-5.0 and 55-60 °C and a melting temperature of 60.7-60.9 °C. They were characterized by similar specific activities (1020-1340 U/mg) against dextrans with a mean molecular mass of 20, 70 and 500 kDa, as well as similar kinetic parameters in the hydrolysis of 70 kDa dextran (Km = 1.10-1.11 g/L, kcat = 640-680 s-1). However, the recombinant dextranases expressed in P. canescens and P. verruculosum had different molecular masses according to the data of SDS-PAGE (∼63 and ∼60 kDa, respectively); this was the result of different N-glycosylation patterns as MALDI-TOF mass spectrometry analysis showed. The main products of dextran hydrolysis at its initial phase were isomaltooligosaccharides, while after the prolonged time (24 h) the reaction system contained isomaltose and glucose as the major products and minor amounts of other oligosaccharides.

Complex effect of lignocellulosic biomass pretreatment with 1-butyl-3-methylimidazolium chloride ionic liquid on various aspects of ethanol and fumaric acid production by immobilized cells within SSF.

The pretreatment of softwood and hardwood samples (spruce and hornbeam wood) with 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) was undertaken for further simultaneous enzymatic saccharification of renewable non-food lignocellulosic biomass and microbial fermentation of obtained sugars to ethanol and fumaric acid. A multienzyme cocktail based on cellulases and yeast or fungus cells producing ethanol and fumaric acid were the main objects of [Bmim]Cl influence studies. A complex effect of lignocellulosic biomass pretreatment with [Bmim]Cl on various aspects of the process (both action of cellulases and microbial conversion of hydrolysates to target products) was revealed. Positive effects of the pretreatment with [Bmim]Cl included decreasing the lignin content in the biomass, and increasing the effectiveness of enzymatic hydrolysis and microbial transformation of pretreated biomass. Immobilized cells of both yeasts and fungi possessed improved productive characteristics in the biotransformation of biomass pretreated with [Bmim]Cl to ethanol and fumaric acid.

Assessment of bacterial resistance to organic solvents using a combined confocal laser scanning and atomic force microscopy (CLSM/AFM).

Using combined confocal laser scanning and atomic force microscopy (CLSM/AFM), bacterial viability under organic solvent stress was assessed at single cell level. Solvent-exposed bacteria stained with the LIVE/DEAD BacLight fluoresced green or red, allowing viable and dead cell discrimination. However, with toluene, butanol and acetonitrile, dually fluorescent cells appeared having compromised cell membranes. Changes in size, surface/volume ratio and roughness were revealed as possible resistance mechanisms.

Simultaneous species-specific PCR detection and viability testing of poly(vinyl alcohol) cryogel-entrapped Rhodococcus spp. after their exposure to petroleum hydrocarbons.

A method of simultaneous species-specific PCR detection and viability testing of poly(vinyl alcohol) cryogel-entrapped Rhodococcus spp. was developed that allowed the estimation of immobilized Rhodococcus opacus and Rhodococcus ruber survival after their exposure to petroleum hydrocarbon mixture. Spectrophotometric INT assay revealed high tolerance of gel-immobilized rhodococci to petroleum hydrocarbons, while among two Rhodococcus strains studied, R. ruber tolerated better to hydrocarbons compared to R. opacus. These findings were confirmed by respirometry results that showed increased respiratory activity of gel-immobilized Rhodococcus strains after 10-day incubation with 3% (v/v) petroleum hydrocarbon mixture. Moreover, jointly incubated rhodococcal strains demonstrated higher oxidative activities toward petroleum hydrocarbons than individual strains. Both Rhodococcus species were recovered successfully in cryogel granules using 16S rDNA-targeted PCR, even though the granules were previously stained with INT and extracted with ethanol. The method developed can be used for rapid detection and monitoring of gel-immobilized bacterial inocula in bioreactors or contaminated soil systems.

Selective adsorption of hydrocarbon-oxidizing Rhodococcus cells in a column with hydrophobized poly(acrylamide) cryogel.

A method for selective adsorption of Rhodococcus cells in the column with hydrophobized poly(acrylamide) cryogel (cryoPAAG) was developed that allowed rhodococci separation from mixed bacterial populations and their effective concentration within a sponge-like gel matrix. Hydrophobization of cryoPAAG using the n-dodecane graft (C12) was performed to enhance the adhesion of Rhodococcus cells to the cryogel; this was suggested by our finding that alkanotrophic rhodococci possess high adhesive activity (91-98%) towards n-alkanes, whereas other Gram-positive and Gram-negative bacteria tested did not adhere strongly to hydrocarbons. The selective index of the hydrophobic C12-cryoPAAG column for Rhodococcus cells was 72% that ensured their separation from complex bacterial cultures. Respirometry results using the Columbus Micro-Oxymax respirometer showed that the maximal respiratory activity of C12-cryoPAAG-immobilized Rhodococcus cells incubated with petroleum hydrocarbons was 1.6-1.8 times higher than that of freely suspended cells, and this correlated with the largest immobilized cell number. Moreover, high respiration rates were maintained over 3 weeks of incubation, indicating a considerable functional stability of the cryoPAAG-immobilized biocatalyst developed.