Production and characterization of pullulan from beet molasses using a nonpigmented strain of Aureobasidium pullulans in batch culture

The production of pullulan from beet molasses by a pigment-free strain of Aureobasidium pullulans on shake-flask culture was investigated. Combined pretreatment of molasses with sulfuric acid and activated carbon to remove potential fermentation inhibitors present in molasses resulted in a maximum pullulan concentration of 24 g/L, a biomass dry wt of 14 g/L, a pullulan yield of 52.5%, and a sugar utilization of 92% with optimum fermentation conditions (initial sugar concentration of 50 g/L and initial pH of 7.0). The addition of other nutrients as carbon and nitrogen supplements (olive oil, ammonium sulfate, yeast extract) did not further improve the production of the exopolysaccharides. Structural characterization of the isolated polysaccharides from the fermentation broths by ¹³C-nuclear magnetic resonance spectroscopy and pullulanase digestion combined with size-exclusion chromatography confirmed the identity of pullulan and the homogeneity (>93% dry basis) of the elaborated polysaccharides by the microorganism. Using multiangle laser light scattering and refractive index detectors in conjunction with high-performance size-exclusion chromatography molecular size distributions and estimates of the molecular weight (M _w =2.1−4.1×10⁵), root mean square of the radius of gyration (R _g =30−38 nm), and polydispersity index (M _w /M _n =1.4−2.4) were obtained. The fermentation products of molasses pretreated with sulfuric acid and/or activated carbon were more homogeneous and free of contaminating proteins. In the concentration range of 2.8−10.0 (w/v), the solution’s rheologic behavior of the isolated pullulans was almost Newtonian (within 1 and 1200 s⁻¹ at 20°C); a slight shear thinning was observed at 10.0 (w/v) for the high molecular weight samples. Overall, beet molasses pretreated with sulfuric acid and activated carbon appears as an attractive fermentation medium for the production of pullulan by A. pullulans.     

Synthesis and antimicrobial activity of new derivatives of pyrano[4',3':4',5']pyrido[3',2':4,5]thieno[3,2-d]pyrimidine and new heterocyclic systems

Taking into account previously obtained biological results on some polyheterocyclic compounds (containing different heteroatoms) and in particular on several 8-amino-5-isopropyl-2,2-dimethyl-10-(methylthio)-1,4-dihydro-2H-pyrano[4’’,3’’:4’,5’]pyrido[3’,2’:4,5]thieno[3,2-d]pyrimidines Ia-v we have carried out the synthesis of twentyone 8-amino-5-isobutyl-2,2-dimethyl-10-(methylthio)-1,4-dihydro-2H-pyrano[4’’,3’’:4’,5’]pyrido[3’,2’:4,5]thieno[3,2-d]pyrimidines 6. Therefore we have slightly modified the structure of the previously studied I introducing at C-5 an isobutyl group instead of the previously examined isopropyl ones in order to see if this variation (changing a little the lipophilicity) will affect the biological activity. Furthermore thieno[3,2-d]pyrimidine-8-thione 7 and their S-alkylated 8 were synthesized. Finally by alkylation of 5-isobutyl-2,2-dimethyl-10-thioxo-1,4,10,11-tetrahydro-2H-pyrano[4'',3'':4',5']pyrido[3',2':4,5]thieno[3,2-d]pyrimidin-8(9H)-one 3 with alkyl dichlorides (bifunctional reagents) we realized the cyclization of a thiazole or thiazine ring on the [b] side of the pyrimidine ring with formation of the new condensed pentaheterocyclic systems: pyrano[4'',3'':4',5']pyrido[3',2':4,5]thieno[3,2-d][1,3]thiazolo[3,2-a]pyrimidin-8-one 11 and pyrano[4''',3''':4'',5'']pyrido[3'',2'':4',5']thieno[3',2':4,5]pyrimido[2,1-b][1,3]thiazin-8-one 12. It was found that some of the synthesized compounds showed interesting antimicrobial activity (by agar diffusion method) against some gram-positive and gram-negative bacilli strains.     

Synergistic enantioseparation systems with either cyclodextrins or cyclofructans and L‐alanine Tert butyl ester lactate

The combined use of chiral ionic liquids (CILs) and conventional chiral selectors (CSs) in CE, to establish a synergistic system, has proven to be an effective approach for the separation of enantiomeric pairs. In this study, a new CE method was developed, employing a binary system of a CS, either a cyclodextrin (CD) or a cyclofructan (CF), and a chiral amino acid ester‐based ionic liquid (AAIL), for the chiral separation of four basic, acidic and zwitterionic drug compounds. In particular, the enantioseparation of two anticoagulants, warfarin (WAR) and coumachlor (COU), a non‐opioid analgesic, nefopam (NEF) and a third‐generation antihistamine, fexofenadine (FXD), was examined, by supporting the BGE with a CS and the chiral AAIL L‐alanine tert butyl ester lactate (L‐AlaC₄Lac). Parameters, such as the type of the CS, the concentration of both the CS and L‐AlaC₄Lac, and the BGE pH, were methodically examined in order to optimize the chiral separation of each analyte. It was observed that, in some cases, the addition of the AAIL into the BGE improved both resolution (R_s) and efficiency (N) significantly. In other cases, the synergistic effect enabled baseline separation of analyte enantiomers, at a much lower concentration of the CS. Finally, after optimization of separation conditions, baseline separations (R_s>1.5) of all four analytes were achieved in less than 5 min.     

BCG vaccination at three different age groups: response and effectiveness

Background  

The protection, which some BCG vaccines could confer against the development of tuberculosis (TB) in childhood, might be indirectly reflected by the subsequent development of BCG immune response. The objectives of the study were to examine effectiveness and possible differences of post-vaccination reaction to a lyophilized BCG at different age groups and to evaluate its protection against TB in a decade's period.     

Some Examples of Graded C*-Algebras

We apply the theory of C*-algebras graded by a semilattice to crossed products of C*-algebras. We establish a correspondence between the spectrum of commutative graded C*-algebras and the spectrum of their components. This will allow us to compute the spectrum of some commutative examples of graded C*-algebras.     

Synthesis and structure of condensed triazolo- and tetrazolopyrimidines

Herein we present the synthesis of several new hydrazino derivatives of cyclopenta[c]pyridine, 5,6,7,8-tetrahydroisoquinoline and pyrano[3,4-c]pyridine from 3-oxo-4-cyano fused pyridine derivatives. The hydrazino derivatives obtained were used as starting materials for the synthesis of isomeric triazolopyrimidines as well as tetrazolopyrimidines. Furthermore, the rearrangement of triazolopyrimidines 7 into triazolopyrimidines 8 is also presented. In DMSO tetrazolopyrimidines 10 were shown to be in equilibrium with the relevant azidopyrimidines 9. The tetrazolopyrimidine structure was confirmed by X-ray crystallography. The synthesized compounds were tested for their antimicrobial activity.     

Carbonic Anhydrase Inhibition with Sulfonamides Incorporating Pyrazole- and Pyridazinecarboxamide Moieties Provides Examples of Isoform-Selective Inhibitors

A series of benzenesulfonamides incorporating pyrazole- and pyridazinecarboxamides decorated with several bulky moieties has been obtained by original procedures. The new derivatives were investigated for the inhibition of four physiologically crucial human carbonic anhydrase (hCA, EC 4.2.2.1.1) isoforms, hCA I and II (cytosolic enzymes) as well as hCA IX and XII (transmembrane, tumor-associated isoforms). Examples of isoform-selective inhibitors were obtained for all four enzymes investigated here, and a computational approach was employed for explaining the observed selectivity, which may be useful in drug design approaches for obtaining inhibitors with pharmacological applications useful as antiglaucoma, diuretic, antitumor or anti-cerebral ischemia drugs.     

Temporal Regulation of PET-RAFT Controlled Radical Depolymerization

A photocatalytic RAFT-controlled radical depolymerization method is introduced for precisely conferring temporal control under visible light irradiation. By regulating the deactivation of the depropagating chains and suppressing thermal initiation, an excellent temporal control was enabled, exemplified by several consecutive “on” and “off” cycles. Minimal, if any, depolymerization could be observed during the dark periods while the polymer chain-ends could be efficiently re-activated and continue to depropagate upon re-exposure to light. Notably, favoring deactivation resulted in the gradual unzipping of polymer chains and a stepwise decrease in molecular weight over time. This synthetic approach constitutes a simple methodology to modulate temporal control during the chemical recycling of RAFT-synthesized polymers while offering invaluable mechanistic insights.     

ATRP Enhances Structural Correlations In Polymerization-Induced Phase Separation**

Synthetic methods to control the structure of materials at sub-micron scales are typically based on the self-assembly of structural building blocks with precise size and morphology. On the other hand, many living systems can generate structure across a broad range of length scales in one step directly from macromolecules, using phase separation. Here, we introduce and control structure at the nano- and microscales through polymerization in the solid state, which has the unusual capability of both triggering and arresting phase separation. In particular, we show that atom transfer radical polymerization (ATRP) enables control of nucleation, growth, and stabilization of phase-separated poly-methylmethacrylate (PMMA) domains in a solid polystyrene (PS) matrix. ATRP yields durable nanostructures with low size dispersity and high degrees of structural correlations. Furthermore, we demonstrate that the length scale of these materials is controlled by the synthesis parameters.