Subpollen particles are rich carriers of major short ragweed allergens and NADH dehydrogenases: quantitative proteomic and allergomic study.

BACKGROUND: Short ragweed (Ambrosia artemisiifolia) allergies affect more than 36 million people annually. Ragweed pollen grains release subpollen particles (SPP) of respirable size upon hydration or a change in air electrical conditions. The aim of this study was to characterize the proteomes and allergomes of short ragweed SPP and total pollen protein extract (TOT), and compare their effects with those of standard aqueous pollen protein extract (APE) using sera from short ragweed pollen-sensitized patients. METHODS: Quantitative 2D gel-based and shotgun proteomics, 1D and 2D immunoblotting, and quantitative ELISA were applied. Novel SPP extraction and preparation protocols enabled appropriate sample preparation and further downstream analysis by quantitative proteomics. RESULTS: The SPP fraction contained the highest proportion (94%) of the allergome, with the largest quantities of the minor Amb a 4 and major Amb a 1 allergens, and as unique, NADH dehydrogenases. APE was the richest in Amb a 6, Amb a 5 and Amb a 3, and TOT fraction was the richest in the Amb a 8 allergens (89% and 83% of allergome, respectively). Allergenic potency correlated well among the three fractions tested, with 1D immunoblots demonstrating a slight predominance of IgE reactivity to SPP compared to TOT and APE. However, the strongest IgE binding in ELISA was noted against APE. New allergenic candidates, phosphoglycerate mutase and phosphoglucomutase, were identified in all the three pollen fractions. Enolase, UTP-glucose-1-phosphate uridylyltransferase and polygalacturonase were observed in SPP and TOT fractions as novel allergens of the short ragweed pollen, as previously described. CONCLUSION AND CLINICAL RELEVANCE: We demonstrated that the complete major (Amb a 1 and 11) and almost all minor (Amb a 3, 4, 5, 6, 8 and 9) short ragweed pollen allergen repertoire as well as NADH oxidases are present in SPP, highlighting an important role for SPP in allergic sensitization to short ragweed.

Peanut protein structure, polyphenol content and immune response to peanut proteins in vivo are modulated by laccase.

Food texture can be improved by enzyme-mediated covalent cross-linking of different food components, such as proteins and carbohydrates. Cross-linking changes the biological and immunological properties of proteins and may change the sensitizing potential of food allergens. In this study we applied a microbial polyphenol oxidase, laccase, to cross-link peanut proteins. The size and morphology of the obtained cross-linked proteins were analyzed by electrophoresis and electron microscopy. Structural changes in proteins were analyzed by CD spectroscopy and by using specific antibodies to major peanut allergens. The bioavailability of peanut proteins was analyzed using a Caco-2 epithelial cell model. The in vivo sensitizing potential of laccase-treated peanut proteins was analyzed using a mouse model of food allergy. Finally, peanut polyphenols were analyzed by UHPLC-MS/MS, before and after the enzymatic reaction with laccase. Laccase treatment of peanut proteins yielded a covalently cross-linked material, with the modified tertiary structure of peanut proteins, improved bioavailability of Ara h 2 (by 70 fold, p < 0.05) and modulated allergic immune response in vivo. The modulation of the immune response was related to the increased production of IgG2a antibodies 11 fold (p < 0.05) and reduced IL-13 secretion in in vitro cultured splenocytes 7 fold (p < 0.05). Analysis of the peanut polyphenol content and profile by HPLC-MS/MS revealed that laccase treatment depleted the peanut extract of polyphenol compounds leaving mostly isorhamnetin derivatives and procyanidin dimer B-type in detectable amounts. Treatment of complex food extracts rich in polyphenols with laccase results in both protein cross-linking and modification of polyphenol compounds. These extensively cross-linked proteins have unchanged potency to induce allergic sensitization in vivo, but certain immunomodulatory changes were observed.

Determination of autoprotolysis constants of some non-aqueous solvents using coulometric titration.

Autoprotolysis constants of acetonitrile, propionitrile, nitromethane, ethylene carbonate and dimethyl sulphoxide were determined using a coulometric - potentiometric method with a hydrogen/palladium electrode as generator. The method is based on the titration of a strong base, tetrabutylammonium hydroxide, with H(+) ions generated by anodic oxidation of hydrogen dissolved in palladium. The titration was carried out in a galvanic cell with glass and calomel electrodes at 25 degrees C. The pK(s) values for the investigated solvents are: acetonitrile, 28.8; propionitrile, 24.6; nitromethane, 23.7; ethylene carbonate. 21.5; and dimethyl sulphoxide 29.1. These data are in accordance with those reported in the literature.

Coulometric generation of protons by oxidation of hydrogen dissolved in palladium, in non-aqueous media.

Coulometric generation of H(+) ions by the oxidation of hydrogen dissolved in palladium, in media such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, acetic anhydride and acetic acid-acetic anhydride mixture, for use in titration of bases, has been investigated. The hydrogen is oxidized at potentials which are much more negative than those of the bases and other components present in the solution. Titrations of numerous bases have established that the oxidation is quantitative and proceeds with 100% current efficiency.

[Imported mussels as a cause of Vibrio parahaemolyticus gastroenteritis]. / Importierte Muscheln als Ursache einer Gastroenteritis durch Vibrio parahaemolyticus.

Two strains of Vibrio parahaemolyticus were isolated from stool specimens of a patient who came down with gastroenteritis 20 hours after eating imported mussels which had not been cooked sufficiently. This is the first documented case of V. parahaemolyticus enteritis acquired in the Federal Republic of Germany.