scholarly journals Localization of hydrogenase in Thiocapsa roseopersicina photosynthetic membrane

1982 ◽  
Vol 202 (1) ◽  
pp. 255-258 ◽  
Author(s):  
Csaba Bagyinka ◽  
Kornel L. Kovács ◽  
Erika Rak
Keyword(s):  
Cell Membrane ◽  
Methyl Viologen ◽  
Photosynthetic Membrane ◽  
Benzyl Viologen ◽  
Thiocapsa Roseopersicina ◽  
Membrane Bound ◽  
Reduced Forms

The photosynthetic cell membrane is impermeable to the oxidized redox dyes Methyl Viologen and Benzyl Viologen, whereas the reduced forms easily penetrate into the cells. By exploiting this permeability difference, the orientation of the membrane-bound hydrogenase has been determined.

scholarly journals Purification of the membrane-bound hydrogenase of Escherichia coli

1979 ◽  
Vol 183 (1) ◽  
pp. 11-22 ◽  
Author(s):  
M W W Adams ◽  
D O Hall
Keyword(s):  
Escherichia Coli ◽  
Methyl Viologen ◽  
Hydrophobic Interaction Chromatography ◽  
H2 Evolution ◽  
Ph Optimum ◽  
Benzyl Viologen ◽  
Electron Carrier ◽  
Membrane Bound ◽  
High Concentrations ◽  
Electron Carriers

The membrane-bound hydrogenase (EC class 1.12) of aerobically grown Escherichia coli cells was solubilized by treatment with deoxycholate and pancreatin. The enzyme was further purified to electrophoretic homogeneity by chromoatographic methods, including hydrophobic-interaction chromatography, with a yield of 10% as judged by activity and an overall purification of 2140-fold. The hydrogenase was a dimer of identical subunits with a mol.wt. of 113,000 and contained 12 iron and 12 acid-labile sulphur atoms per molecule. The epsilon 400 was 49,000M-1 . cm-1. The hydrogenase catalysed both H2 evolution and H2 uptake with a variety of artificial electron carriers, but would not interact with flavodoxin, ferredoxin or nicotinamide and flavin nucleotides. We were unable to identify any physiological electron carrier for the hydrogenase. With Methyl Viologen as the electron carrier, the pH optimum for H2 evolution and H2 uptake was 6.5 and 8.5 respectively. The enzyme was stable for long periods at neutral pH, low temperatures and under anaerobic conditions. The half-life of the hydrogenase under air at room temperature was about 12 h, but it could be stabilized by Methyl Viologen and Benzyl Viologen, both of which are electron carriers for the enzyme, and by bovine serum albumin. The hydrogenase was strongly inhibited by carbon monoxide (Ki = 1870Pa), heavy-metal salts and high concentrations of buffers, but was resistant to inhibition by thiol-blocking and metal-complexing reagents. These aerobically grown E. coli cells lacked formate hydrogenlyase activity and cytochrome c552.

scholarly journals Two Atypical Enteropathogenic Escherichia coli Strains Induce the Production of Secreted and Membrane-Bound Mucins To Benefit Their Own Growth at the Apical Surface of Human Mucin-Secreting Intestinal HT29-MTX Cells

2010 ◽  
Vol 78 (3) ◽  
pp. 927-938 ◽  
Author(s):  
Mônica A. M. Vieira ◽  
Tânia A. T. Gomes ◽  
Antonio J. P. Ferreira ◽  
Terezinha Knöbl ◽  
Alain L. Servin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Membrane ◽  
Brush Border ◽  
Apical Surface ◽  
Enteropathogenic Escherichia Coli ◽  
Typical Epec ◽  
Membrane Bound

ABSTRACT In rabbit ligated ileal loops, two atypical enteropathogenic Escherichia coli (aEPEC) strains, 3991-1 and 0421-1, intimately associated with the cell membrane, forming the characteristic EPEC attachment and effacement lesion of the brush border, induced a mucous hypersecretion, whereas typical EPEC (tEPEC) strain E2348/69 did not. Using cultured human mucin-secreting intestinal HT29-MTX cells, we demonstrate that apically aEPEC infection is followed by increased production of secreted MUC2 and MUC5AC mucins and membrane-bound MUC3 and MUC4 mucins. The transcription of the MUC5AC and MUC4 genes was transiently upregulated after aEPEC infection. We provide evidence that the apically adhering aEPEC cells exploit the mucins' increased production since they grew in the presence of membrane-bound mucins, whereas tEPEC did not. The data described herein report a putative new virulence phenomenon in aEPEC.

Fourier-transform detection of singlet oxygen and fluorescence from cell membrane bound porphyrins

1994 ◽  
Vol 90 (17) ◽  
pp. 2453-2454 ◽  
Author(s):  
Fritz Böhm ◽  
George Marston ◽  
T. George Truscott ◽  
Richard P. Wayne
Keyword(s):  
Fourier Transform ◽  
Cell Membrane ◽  
Singlet Oxygen ◽  
Membrane Bound

The Proinflammatory Cytokine Interleukin-12 Occurs as a Cell Membrane-Bound Form on Macrophages

1996 ◽  
Vol 225 (3) ◽  
pp. 1063-1067 ◽  
Author(s):  
Xiaohong Fan ◽  
Vladimir Sibalic ◽  
Eva Niederer ◽  
Rudolf P. Wüthrich
Keyword(s):  
Cell Membrane ◽  
Proinflammatory Cytokine ◽  
Interleukin 12 ◽  
A Cell ◽  
Membrane Bound
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