The receptor for IgA, Fc alpha RI or CD89, is expressed on myeloid cells and can trigger phagocytosis, tumor cell lysis, and release of inflammatory mediators. These functions critically depend on the associated FcR gamma-chain; however, some biological functions, like receptor internalization, are solely mediated by Fc alpha RI alpha-chain. Little is known as to how Fc alpha RI regulates these processes and the Fc alpha RI intracellular domain does not contain recognized signalling motifs. We searched for associating proteins and identified c-Jun activating binding protein 1 (JAB1) as a binding partner specifically for Fc alpha RI. We found increased Fc alpha RI surface expression after ectopic expression of JAB1 as well as diminished protein levels of total FcR gamma-chain levels after JAB1 knock-down. These data functionally link JAB1 with controlling protein expression levels of Fc alpha RI-FcR gamma-chain protein complex.

The prototypic receptor for IgA (FcalphaRI, CD89) is expressed on myeloid cells and can trigger phagocytosis, tumor cell lysis, and release of inflammatory mediators. The functions of FcalphaRI and activating receptors for IgG (FcgammaRI and FcgammaRIII) are dependent on the FcR gamma-chain dimer. This study increases our understanding of the molecular basis of the FcalphaRI-FcR gamma-chain transmembrane interaction, which is distinct from that of other activatory FcRs. FcalphaRI is unique in its interaction with the common FcR gamma-chain, because it is based on a positively charged residue at position 209, which associates with a negatively charged amino acid of FcR gamma-chain. We explored the importance of the position of this positive charge within human FcalphaRI for FcR gamma-chain association and FcalphaRI functioning with the use of site-directed mutagenesis. In an FcalphaRI R209L/A213H mutant, which represents a vertical relocation of the positive charge, proximal and distal FcR gamma-chain-dependent functions, such as calcium flux, MAPK phosphorylation, and IL-2 release, were similar to those of wild-type FcalphaRI. A lateral transfer of the positive charge, however, completely abrogated FcR gamma-chain-dependent functions in an FcalphaRI R209L/M210R mutant. By coimmunoprecipitation, we have demonstrated the loss of a physical interaction between FcR gamma-chain and FcalphaRI M210R mutant, thus explaining the loss of FcR gamma-chain-dependent functions. In conclusion, not only the presence of a basic residue in the transmembrane region of FcalphaRI, but also the orientation of FcalphaRI toward the FcR gamma-chain dimer is essential for FcR gamma-chain association. This suggests the involvement of additional amino acids in the FcalphaRI-FcR gamma-chain interaction.

The prototypic receptor for IgA (FcαRI, CD89) is expressed on myeloid cells and can trigger phagocytosis, tumor cell lysis, and release of inflammatory mediators. The functions of FcαRI and activating receptors for IgG (FcγRI and FcγRIII) are dependent on the FcR γ-chain dimer. This study increases our understanding of the molecular basis of the FcαRI-FcR γ-chain transmembrane interaction, which is distinct from that of other activatory FcRs. FcαRI is unique in its interaction with the common FcR γ-chain, because it is based on a positively charged residue at position 209, which associates with a negatively charged amino acid of FcR γ-chain. We explored the importance of the position of this positive charge within human FcαRI for FcR γ-chain association and FcαRI functioning with the use of site-directed mutagenesis. In an FcαRI R209L/A213H mutant, which represents a vertical relocation of the positive charge, proximal and distal FcR γ-chain-dependent functions, such as calcium flux, MAPK phosphorylation, and IL-2 release, were similar to those of wild-type FcαRI. A lateral transfer of the positive charge, however, completely abrogated FcR γ-chain-dependent functions in an FcαRI R209L/M210R mutant. By coimmunoprecipitation, we have demonstrated the loss of a physical interaction between FcR γ-chain and FcαRI M210R mutant, thus explaining the loss of FcR γ-chain-dependent functions. In conclusion, not only the presence of a basic residue in the transmembrane region of FcαRI, but also the orientation of FcαRI toward the FcR γ-chain dimer is essential for FcR γ-chain association. This suggests the involvement of additional amino acids in the FcαRI-FcR γ-chain interaction.

The non-coloured phenolic fraction of fortified port wines was studied. Trials using several mash-extraction techniques which may be used during port wine making were evaluated for their effectiveness by measuring qualitative and quantitative differences in phenolics. Total phenolic compounds measured by spectrophotometry and HPLC analysis were compared, and the greater values obtained using spectrophotometry are attributable to the contribution of anthocyanins and non-phenolic UV-absorbing compounds. Quantitative and qualitative differences in composition were observed depending on the extraction mode. The greatest total phenolic content was found in port wine made by traditional foot treading, while early addition of extra alcohol to the mash had a neutral or negative effect on the yield of phenolic compounds.

Extracts of commercial brands of orange juice were prepared by sweeping the headspace of the juice onto an adsorbent trap, using different volumes of carrier gas, different temperatures and different volumes of juice. The contents of the trap were desorbed into 1,2-propanediol and diluted. The aromas of these preparations were compared with those of the actual juices by sensory analysis, using fixed vocabulary profiling. There were significant differences between the aromas of the extracts and the juices, although the aromas of the extracts were not significantly affected by the extraction conditions. The results show that more attention must be given to optimising the conditions used for the extraction of volatiles in sensory/instrumental studies of aroma.

An instrumental technique to study the flavour release of diacetyl (2 g litre−1) from model food systems (water, sunflower oil and oil-in-water and water-in-oil emulsions) was developed. Experimental partition coefficients are given for diacetyl at 25°C at atmospheric pressure in model food systems. Flavour release of diacetyl was measured using headspace gas chromatography and calculated using a model based on Fick's law.

AbstractThe distribution and content of anthocyanins in young port wines made in three successive years (1981–1983) from up to sixteen grape cultivars grown at five different sites in the Douro Valley in Northern Portugal has been assessed by high performance liquid chromatography. Distributions are confined to the seven most readily separated and identified anthocyanins and expressed as percentages of their sum (78–97% of the total integrated area). Anthocyanins based on malvidin (Mv) predominated (57–94%). Of these Mv 3‐glucoside was the major pigment (43‐76%), followed usually by Mv 3‐p‐coumarylglucoside (1–38%) and then Mv 3‐acetylglucoside (2–18%). Peonidin 3‐glucoside (2–39%) was prominent in a few cultivars but delphinidin 3‐glucoside (1–13%), petunidin 3‐glucoside (2–12%) and cyanidin 3‐glucoside (trac‐4%) were of low proportions throughout. The ratio Mv 3‐acetylglucoside/total Mv glucosides appeared characteristic of cultivar, independent of site and a useful aid to identification. The percentages of Mv 3‐p‐coumarylglucoside were usually lower in ports than in grape skin extracts of the same cultivars. The contents of total anthocyanins in the ports ranged from 143–1080 mg 1−1 (expressed as malvidin 3‐glucoside chloride) and varied according to site and season.

The distribution of anthocyanins in methanolic skin extracts of 16 grape cultivars used for port wine production and grown at five sites in the Douro Valley in Northern Portugal has been assessed by high performance liquid chromatography. Results are confined to the seven most readily separated and identified anthocyanins and are expressed as percentages of their total (88–99% of the total integrated area). Anthocyanins based on malvidin (Mv) predominated. Of these, Mv 3‐glucoside was the major pigment (33–60%), being exceeded by Mv 3‐ p ‐coumarylglucoside (2–51%) in only two cultivars; Mv 3‐acetylglucoside (1–15%) was consistently the lowest. Peonidin 3‐glucoside (1–27%) was prominent in four cultivars, but delphinidin 3‐glucoside (1–11%), petunidin 3‐glucoside (2–11%) and cyanidin 3‐glucoside (trace‐6%) were of low proportions throughout. The ratio Mv 3‐acetylglucoside/total Mv glucosides appeared characteristic of cultivar, independent of site, and a useful aid to identification of grape cultivars. The coloured pulp of some cultivars contained peonidin 3‐glucoside as a major component, present in greater proportions than in the skin; the percentage of Mv 3‐ p ‐coumarylglucoside was lower in pulp than in skin. The identities of six of the seven anthocyanins were confirmed by fast atom bombardment mass spectrometry and the structures of the Mv derivatives were determined by nuclear magnetic resonance. The formation of formyl and acetyl anthocyanin artefacts is described.

International Journal of Food Science & TechnologyVolume 19, Issue 6 p. 659-671 Effect of colour on the assessment of ports ANTHONY A. WILLIAMS, ANTHONY A. WILLIAMS Food and Beverages Division, Long Ashton Research Station, University of Bristol, Long Ashton, Bristol BS18 9AF, U.K.Search for more papers by this authorSTEVEN P. LANGRON, STEVEN P. LANGRON Food and Beverages Division, Long Ashton Research Station, University of Bristol, Long Ashton, Bristol BS18 9AF, U.K. Present address: Pedigree Petfoods Ltd., Melton Mowbray, Leicestershire LE13 1BB, U. K.Search for more papers by this authorCOLIN F. TIMBERLAKE, COLIN F. TIMBERLAKE Food and Beverages Division, Long Ashton Research Station, University of Bristol, Long Ashton, Bristol BS18 9AF, U.K.Search for more papers by this authorJOHANNA BAKKER, JOHANNA BAKKER Food and Beverages Division, Long Ashton Research Station, University of Bristol, Long Ashton, Bristol BS18 9AF, U.K.Search for more papers by this author ANTHONY A. WILLIAMS, ANTHONY A. WILLIAMS Food and Beverages Division, Long Ashton Research Station, University of Bristol, Long Ashton, Bristol BS18 9AF, U.K.Search for more papers by this authorSTEVEN P. LANGRON, STEVEN P. LANGRON Food and Beverages Division, Long Ashton Research Station, University of Bristol, Long Ashton, Bristol BS18 9AF, U.K. Present address: Pedigree Petfoods Ltd., Melton Mowbray, Leicestershire LE13 1BB, U. K.Search for more papers by this authorCOLIN F. TIMBERLAKE, COLIN F. TIMBERLAKE Food and Beverages Division, Long Ashton Research Station, University of Bristol, Long Ashton, Bristol BS18 9AF, U.K.Search for more papers by this authorJOHANNA BAKKER, JOHANNA BAKKER Food and Beverages Division, Long Ashton Research Station, University of Bristol, Long Ashton, Bristol BS18 9AF, U.K.Search for more papers by this author First published: December 1984 https://doi.org/10.1111/j.1365-2621.1984.tb01885.xCitations: 17 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume19, Issue6December 1984Pages 659-671 RelatedInformation