The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Anthony P Pugsley - One of the best experts on this subject based on the ideXlab platform.
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recent progress and future directions in studies of the main Terminal Branch of the general secretory pathway in gram negative bacteria a review
Gene, 1997Co-Authors: Anthony P Pugsley, Olivera Francetic, Odile Possot, Nathalie Sauvonnet, Kim R HardieAbstract:Abstract The main Terminal Branch (MTB) of the general secretory pathway is used by a wide variety of Gram− bacteria to transport exoproteins from the periplasm to the outside milieu. Recent work has led to the identification of the function of two of its 14 (or more) components: an enzyme with type-IV prepilin peptidase activity and a chaperone-like protein required for the insertion of another of the MTB components into the outer membrane. Despite these important discoveries, little tangible progress has been made towards identifying MTB components that determine secretion specificity (presumably by binding to cognate exoproteins) or which form the putative channel through which exoproteins are transported across the outer membrane. However, the idea that the single integral outer membrane component of the MTB could line the wall of this channel, and the intriguing possibility that other components of the MTB form a rudimentary type-IV pilus-like structure that might span the periplasm both deserve more careful examination. Although Escherichia coli K-12 does not normally secrete exoproteins, its chromosome contains an apparently complete set of genes coding for MTB components. At least two of these genes code for functional proteins, but the operon in which twelve of the genes are located does not appear to be expressed. We are currently searching for conditions which allow these genes to be expressed with the eventual aim of identifying the protein(s) that E. coli K-12 can secrete.
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energy requirement for pullulanase secretion by the main Terminal Branch of the general secretory pathway
Molecular Microbiology, 1997Co-Authors: Odile Possot, Lucienne Letellier, Anthony P PugsleyAbstract:The energy requirement for the second step in pullulanase secretion by the general secretory pathway was studied in Escherichia coli. In order to uncouple the two steps in the secretion pathway (across the cytoplasmic and outer membranes, respectively) and to facilitate kinetic analysis of secretion, a variant form of pullulanase lacking its N-Terminal fatty acid membrane anchor was used. The transport of the periplasmic secretion intermediate form of this protein across the outer membrane was not inhibited by concentrations of sodium arsenate in excess of those required to reduce ATP levels to ≤10% of their normal value. Pullulanase secretion was inhibited by the protonophore carbonyl cyanide m-chlorophenyl hydrazone at concentrations which were similar to those reported by others to be required to prevent solute uptake or the export and processing of preproteins across the cytoplasmic membrane, but which were in excess of those required to fully dissipate the proton-motive force and to reduce lactose uptake to a significant extent.
Sungseen Choi - One of the best experts on this subject based on the ideXlab platform.
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novel analytical method for determination of contents of backbone and Terminal Branch vinyl acetate groups of poly ethylene co vinyl acetate using deacetylation reaction
Polymer Testing, 2016Co-Authors: Sungseen ChoiAbstract:Abstract Vinyl acetate (VA) groups in poly(ethylene-co-vinyl acetate) (EVA) exist in backbone, Terminal, and Branch positions. The VA moieties were converted to carbon-carbon double bonds (∼CH=CH∼) by deacetylation reaction. By deacetylation, the backbone VA group was converted to 1,4-unit (∼CH2CH=CHCH2∼) while the Terminal and Branch ones were converted to 1,2-unit (∼CH=CH2). A novel analytical method for determination of ratio of backbone and Terminal/Branch VA contents was developed using off-line pyrolysis and transmission-Fourier transform infrared spectroscopy (FTIR). The analytical method included sample preparation of deacetylated EVA coated on NaCl window for transmission-FTIR analysis and calculation of backbone and Terminal/Branch VA contents using quantitative analysis of 1,4- and 1,2-units of the deacetylated EVA. Influence of deacetylation conditions (pyrolysis temperatures and times) on degree of deacetylation and other side reactions was also investigated, and proper deacetylation condition was suggested. From the experimental results, proper off-line pyrolysis condition of EVA coated on NaCl window was 300 °C for 60–80 min. The novel analytical method was reliable with the experimental error of below 5%.
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Novel analytical method for determination of contents of backbone and Terminal/Branch vinyl acetate groups of poly(ethylene-co-vinyl acetate) using deacetylation reaction
Polymer Testing, 2016Co-Authors: Sungseen ChoiAbstract:Abstract Vinyl acetate (VA) groups in poly(ethylene-co-vinyl acetate) (EVA) exist in backbone, Terminal, and Branch positions. The VA moieties were converted to carbon-carbon double bonds (∼CH=CH∼) by deacetylation reaction. By deacetylation, the backbone VA group was converted to 1,4-unit (∼CH2CH=CHCH2∼) while the Terminal and Branch ones were converted to 1,2-unit (∼CH=CH2). A novel analytical method for determination of ratio of backbone and Terminal/Branch VA contents was developed using off-line pyrolysis and transmission-Fourier transform infrared spectroscopy (FTIR). The analytical method included sample preparation of deacetylated EVA coated on NaCl window for transmission-FTIR analysis and calculation of backbone and Terminal/Branch VA contents using quantitative analysis of 1,4- and 1,2-units of the deacetylated EVA. Influence of deacetylation conditions (pyrolysis temperatures and times) on degree of deacetylation and other side reactions was also investigated, and proper deacetylation condition was suggested. From the experimental results, proper off-line pyrolysis condition of EVA coated on NaCl window was 300 °C for 60–80 min. The novel analytical method was reliable with the experimental error of below 5%.
Odile Possot - One of the best experts on this subject based on the ideXlab platform.
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recent progress and future directions in studies of the main Terminal Branch of the general secretory pathway in gram negative bacteria a review
Gene, 1997Co-Authors: Anthony P Pugsley, Olivera Francetic, Odile Possot, Nathalie Sauvonnet, Kim R HardieAbstract:Abstract The main Terminal Branch (MTB) of the general secretory pathway is used by a wide variety of Gram− bacteria to transport exoproteins from the periplasm to the outside milieu. Recent work has led to the identification of the function of two of its 14 (or more) components: an enzyme with type-IV prepilin peptidase activity and a chaperone-like protein required for the insertion of another of the MTB components into the outer membrane. Despite these important discoveries, little tangible progress has been made towards identifying MTB components that determine secretion specificity (presumably by binding to cognate exoproteins) or which form the putative channel through which exoproteins are transported across the outer membrane. However, the idea that the single integral outer membrane component of the MTB could line the wall of this channel, and the intriguing possibility that other components of the MTB form a rudimentary type-IV pilus-like structure that might span the periplasm both deserve more careful examination. Although Escherichia coli K-12 does not normally secrete exoproteins, its chromosome contains an apparently complete set of genes coding for MTB components. At least two of these genes code for functional proteins, but the operon in which twelve of the genes are located does not appear to be expressed. We are currently searching for conditions which allow these genes to be expressed with the eventual aim of identifying the protein(s) that E. coli K-12 can secrete.
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energy requirement for pullulanase secretion by the main Terminal Branch of the general secretory pathway
Molecular Microbiology, 1997Co-Authors: Odile Possot, Lucienne Letellier, Anthony P PugsleyAbstract:The energy requirement for the second step in pullulanase secretion by the general secretory pathway was studied in Escherichia coli. In order to uncouple the two steps in the secretion pathway (across the cytoplasmic and outer membranes, respectively) and to facilitate kinetic analysis of secretion, a variant form of pullulanase lacking its N-Terminal fatty acid membrane anchor was used. The transport of the periplasmic secretion intermediate form of this protein across the outer membrane was not inhibited by concentrations of sodium arsenate in excess of those required to reduce ATP levels to ≤10% of their normal value. Pullulanase secretion was inhibited by the protonophore carbonyl cyanide m-chlorophenyl hydrazone at concentrations which were similar to those reported by others to be required to prevent solute uptake or the export and processing of preproteins across the cytoplasmic membrane, but which were in excess of those required to fully dissipate the proton-motive force and to reduce lactose uptake to a significant extent.
M Dunkerton - One of the best experts on this subject based on the ideXlab platform.
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the Terminal Branch of posterior interosseous nerve a useful donor for digital nerve grafting
Journal of Hand Surgery (European Volume), 1992Co-Authors: N Reissis, A Stirrat, S Manek, M DunkertonAbstract:Abstract The anatomical relationships of the Terminal Branch of posterior interosseous nerve have been studied in 57 cadaver and amputation specimens. Removal of the nerve leaves the patient with no apparent sensory deficit. In all dissections the nerve was present and its location was constant. The mean obtainable length was 3.7 cm (range 2.7–5.1 cm) and its cross-sectional area made the nerve suitable for grafting of digital nerves.
N Reissis - One of the best experts on this subject based on the ideXlab platform.
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the Terminal Branch of posterior interosseous nerve a useful donor for digital nerve grafting
Journal of Hand Surgery (European Volume), 1992Co-Authors: N Reissis, A Stirrat, S Manek, M DunkertonAbstract:Abstract The anatomical relationships of the Terminal Branch of posterior interosseous nerve have been studied in 57 cadaver and amputation specimens. Removal of the nerve leaves the patient with no apparent sensory deficit. In all dissections the nerve was present and its location was constant. The mean obtainable length was 3.7 cm (range 2.7–5.1 cm) and its cross-sectional area made the nerve suitable for grafting of digital nerves.
