Demonstration of event position reconstruction based on diffusion in the NEXT-white detector.

Noble element time projection chambers are a leading technology for rare event detection in physics, such as for dark matter and neutrinoless double beta decay searches. Time projection chambers typically assign event position in the drift direction using the relative timing of prompt scintillation and delayed charge collection signals, allowing for reconstruction of an absolute position in the drift direction. In this paper, alternate methods for assigning event drift distance via quantification of electron diffusion in a pure high pressure xenon gas time projection chamber are explored. Data from the NEXT-White detector demonstrate the ability to achieve good position assignment accuracy for both high- and low-energy events. Using point-like energy deposits from 83mKr calibration electron captures (E∼45 keV), the position of origin of low-energy events is determined to 2 cm precision with bias <1mm. A convolutional neural network approach is then used to quantify diffusion for longer tracks (E≥1.5 MeV), from radiogenic electrons, yielding a precision of 3 cm on the event barycenter. The precision achieved with these methods indicates the feasibility energy calibrations of better than 1% FWHM at Qßß in pure xenon, as well as the potential for event fiducialization in large future detectors using an alternate method that does not rely on primary scintillation.

Isolation and structural identification of glycopolymers of Bifidobacterium bifidum BIM B-733D as putative players in pathogenesis of autoimmune thyroid diseases.

Bifidobacterium bifidum 791 (commercially available as B. bifidum BIM B-733D) cell-surface biopolymers (BPs) interact selectively with human serum thyroid peroxidase (TPO) and thyroglobulin (Tg) autoantibodies (anti TPO and anti Tg, respectively). BPanti-TPO and BPanti-Tg were isolated from the soluble fraction of B. bifidum BIM B-733D by affinity chromatography with anti-TPO or anti-Tg, respectively. Homogeneity of affinity eluates (AEanti-TPO and AEanti-Tg) was tested by size exclusion chromatography. For each AE, the elution profiles generated on the basis of absorbance at 280 nm do not conform to ELISA data for functional activity characteristic of BPs. Moreover, high functional activity was detected in chromatographic fractions that had significantly different molecular weights and no absorbance at 280 nm, which suggests a non-protein (carbohydrate) nature of BPanti-TPO and BPanti-Tg. The semi-preparative size exclusion chromatography of AEanti-TPO and AEanti-Tg with detection by refractometer gave 5,000-7,000 Da fractions containing substances that interact selectively with either anti TPO (BPanti-TPO) or anti-Tg (BPanti-Tg) according to ELISA data. Analysis by two-dimensional NMR spectroscopy including a 1H, 13C-heteronuclear single-quantum coherence experiment indicated that both substances are linear α-1,6-glucans. For the first time, an immunological similarity (molecular mimicry) of glycopolymers of B. bifidum BIM B-733D and human thyroid proteins, TPO and Tg, was shown. On the whole, our data point to a possible role of bifidobacteria in the pathogenesis of autoimmune thyroid diseases (ATD). The main requirements for triggering/acceleration or prevention/abrogation of ATD by bifidobacteria through molecular mimicry mechanism are hypothesised to be (1) genetic predisposition to ATD and (2) intestinal epithelium penetration by α-1,6-glucan.

The role of components of Bifidobacterium and Lactobacillus in pathogenesis and serologic diagnosis of autoimmune thyroid diseases.

During recent years, researchers have been focusing on the concept of an infectious etiology of autoimmune diseases. The most discussed theory is molecular mimicry, i.e. the emergence of autoreactive clones of T- and B-lymphocytes as a result of cross-immune response to homologous bacterial or viral antigen. Information on the role of probiotic microorganisms (PM) in the molecular mechanisms of autoimmune thyroid diseases (ATD) is limited. Using proteins and immunogenic peptides databanks and relevant computer programs, the homology between the amino acid sequences of thyroid peroxidase (TPO) and thyroglobulin (Tg), which are potential B- and T-cell epitopes of these antigens, and proteins of bifidobacteria and lactobacilli was established. Moreover, we have found components of cells of Bifidobacterium bifidum 791, Bifidobacterium adolescentis 94 BIM, Bifidobacterium longum B379M and Lactobacillus plantarum B-01 that selectively bind human antibodies to TPO (anti-TPO) and antibodies to Tg (anti-Tg) and compete with natural antigens for the binding of anti-TPO and anti-Tg in ELISA. Additionally, a three-fold difference was observed between the probability of detecting antibodies (Abs) to the antigens of L. plantarum B-01 and B. bifidum 791 in serum samples containing and those not containing anti-TPO. On the whole, our data are arguments in favour of the assumption of the possible role of PM of the genera Bifidobacterium and Lactobacillus in triggering ATD by the mechanism of molecular mimicry. The data obtained in silico and in vitro should be proven by use of animal models and clinical studies for extrapolations to the whole body. Possible antigenic properties of components/proteins of bifidobacteria and lactobacilli, selectively binding anti-TPO and anti-Tg should be taken into consideration. Natural human Abs to these bacterial components are probably able to cross-react with the TPO and Tg in the ELISA for detection of anti-TPO and anti-Tg, which are serologic markers of ATD. It can lead to unspecific false positive results and, hence, to an incorrect diagnosis.

Bacteriophage receptors, mechanisms of phage adsorption and penetration into host cell.

Bacteriophages are an attractive tool for application in the therapy of bacterial infections, for biological control of bacterial contamination of foodstuffs in the alimentary industry, in plant protection, for control of water-borne pathogens, and control of environmental microflora. This review is mainly focused on structures governing phage recognition of host cell and mechanisms of phage adsorption and penetration into microbial cell.

Application of enzymes, sodium tripolyphosphate and cation exchange resin for the release of extracellular polymeric substances from sewage sludge. Characterization of the extracted polysaccharides/glycoconjugates by a panel of lectins.

The study describes extraction of extracellular polymeric substances (EPS) from sewage sludge by applying enzymes and enzymes combined with sodium tripolyphosphate (STPP). Additionally, a systematic study of two non-enzymatic extraction agents is described. The assessment of the released products is made by colorimetrical methods and polysaccharides/glycoconjugates identification by the interaction with four immobilized lectins. Bio-sludge from Helsingborg (Sweden) and Damhusåen (Denmark) were used as two case studies for testing enzymatic extractability and thereby to make useful prediction of sludge bio-digestibility. From Helsingborg sludge the enzymes extracted about 40% more of EPS than from Damhusåen. The polysaccharides/glycoconjugates in both sludges maintained the same level, and showed substantial different interaction motifs with lectins panel. Damhusåen enzymatic extracted EPS had an enhanced amount of suspended material that was post-hydrolysed by the use of polygalacturonase and lysozyme resulting in pectin like polymers and petiptidoglycans. Petiptidoglycan is a marker from bacterial cell debris. STPP and cation exchange resin (CER) released different quantities of EPS. The CER released polysaccharides/glycoconjugates had higher molecular weight and stronger affinity towards Concanavalin A than the one released by the action of STPP. Independent of the extraction conditions, STPP released elevated amounts of polyvalent cations and humic substances in contrast to the very low amounts of released by CER.

[Fractions of barley spent grain as media for growth of probiotic bacteria].

The application of the protein and polysaccharide fractions of barley spent grain as a basis of growth media for probiotic bacteria was studied. High values of biomass yield, cell viability, and organic acid production were observed in the variants of media containing the barley spent grain supplemented with lactose, ascorbic acid, yeast extract, and mineral salts. Cells of lactic acid bacteria and bifidobacteria had the typical rod-shaped morphology.

Artificial carrier for oxygen supply in biological systems.

Several poly (dimethylsiloxanes) (PDMS) copolymers of dimethylsiloxane (DMS) with ethylene or propylene oxide were tested as artificial carriers for the delivery of oxygen to biological systems. Copolymers with a DMS content of 33% or lower enhanced glucose oxidation by 200% in contrast to the 25% increase produced by the same concentration of perfluorodecalin. When 0.05% of the copolymer with 18% DMS was included in the growth media of Bacillus thuriginensis, the biomass (growth rate) increased 1.5-fold. With 0.1% of this copolymer, actinorhodin production by Streptomyces coelicolor A3 (2) occurred in half the normal time and with an increased yield. In conclusion, these PDMS copolymers are a good alternative to perfluorodecalin as oxygen carriers in biotechnological processes.

A novel esterase from Saccharomyces carlsbergensis, a possible function for the yeast TIP1 gene.

An extracellular esterase was isolated from the brewer's yeast, Saccharomyces carlsbergensis. Inhibition by diisopropyl fluorophosphate shows that the enzyme has a serine active site. By mass spectrometry, the molecular weight of the enzyme was 16.9 kDa. The optimal pH for activity was in the range of four to five. Esterase activity was found in beer before pasteurization, and a low level of activity was still present after pasteurization. Caprylic acid, which is present in beer, competitively inhibited the esterase. The substrate preference towards esters of p-nitrophenol indicated that the enzyme prefers esters of fatty acids from four to 16 carbon atoms. The esterase has lipolytical activity; olive oil (C-18:1), which is a classical substrate for lipase, was hydrolysed. N-terminal sequence analysis of the esterase yielded a sequence which was identical to the deduced amino acid sequence of the S. cerevisiae TIP1 gene. The esterase preparation did not appear to contain significant amounts of other proteins than Tip1p, indicating that the TIP1 gene is the structural gene for the esterase.

Novel serine penicillocarboxypeptidase CPD-S3 from Penicillium janthinellum IBT 3991: purification, characterization, and uses in peptide synthesis and modification.

A novel carboxypeptidase (CPD-S3) from Penicillium janthinellum IBT 3991 has been isolated in a two-step purification procedure by cation exchange and affinity chromatography. The enzyme is a serine carboxypeptidase with a denatured molecular mass determined by SDS of 62 kDa of which 32% is carbohydrate. The isoelectric point is 5.1. CPD-S3 exhibits a high stability towards organic solvents and elevated temperatures. Besides the carboxypeptidase activity, CPD-S3 exhibits esterase, amidase, and carboxamidohydrolase activities. CPD-S3 favors substrates of L-configuration with basic amino acid residues in either P1 or P1', and particularly dibasic substrates and medium-sized straight-chain alkyl esters for hydrolysis. In aminolysis of esters, amino acid amides and hydrazines coupled in good yield, but methyl esters poorly, and unlike other carboxypeptidases, free amino acids could not be coupled or transpeptidation effected to form amides. In ester semisynthesis, peptides with neutral, but not basic, residues in P1 could be esterified. The scope of applicability for enzymatic peptide synthesis is limited.

Proline-specific endopeptidases from microbial sources: isolation of an enzyme from a Xanthomonas sp.

An extensive screening among microorganisms for the presence of post-proline-specific endopeptidase activity was performed. This activity was found among ordinary bacteria from soil samples but not among fungi and actinomycetes. This result is in contrast to the previous notion that this activity is confined to the genus Flavobacterium. A proline endopeptidase was isolated from a Xanthomonas sp. and characterized with respect to physicochemical and enzymatic properties. The enzyme is composed of a single peptide chain with a molecular weight of 75,000. The isoelectric point is 6.2. It is inhibited by diisopropylfluorophosphate and may therefore be classified as a serine endopeptidase. The activity profile is bell shaped with an optimum at pH 7.5. By using synthetic peptide substrates and intramolecular fluorescence quenching it was possible to study the influence of substrate structure on the rate of hydrolysis. The enzyme specifically hydrolyzed Pro-X peptide bonds. With Glu at position X, low rates of hydrolysis were observed; otherwise the enzyme exhibited little preference for particular amino acid residues at position X. A similar substrate preference was observed with respect to the amino acid residue preceding the prolyl residue in the substrate. The enzyme required a minimum of two amino acid residues toward the N terminus from the scissile bond, but further elongation of the peptide chain by up to six amino acid residues caused only a threefold increase in the rate of hydrolysis. Attempts to cleave at the prolyl residues in oxidized RNase failed, indicating that the enzyme does not hydrolyze long peptides, a peculiar property it shares with other proline-specific endopeptidases.

Characterization of a D-amino acid oxidase with high activity against cephalosporin C from the yeast Trigonopsis variabilis.

We describe an improved method to purify D-amino acid oxidase with activity towards cephalosporin C. The protein has a carbohydrate content of 1.3% and two molecules of non-covalently bound flavin cofactor per protein molecule. HPLC profiles and enzymatic analysis have indicated that the cofactor is FAD, even though fluorescence spectroscopy shows a slightly altered spectral profile in the 400-500 nm range compared to authentic FAD. N-terminal sequencing of the protein revealed a high level of similarity (56% identity in 25 amino acids) between the fungal and mammalian oxidase, and probably represents a "Rossman fold" with a beta-alpha-beta structure for the binding of the adenosyl moiety of the cofactor.