scholarly journals Role of oxygen radicals in the phototoxicity of tetracyclines toward Escherichia coli B.

1987 ◽  
Vol 169 (6) ◽  
pp. 2516-2522 ◽  
Author(s):  
J P Martin ◽  
K Colina ◽  
N Logsdon
Keyword(s):  
Escherichia Coli ◽  
Oxygen Radicals ◽  
Escherichia Coli B

Über die Zellmembran von Escherichia Coli B

1954 ◽  
Vol 9 (6) ◽  
pp. 398-406 ◽  
Author(s):  
Wolfhard Weidel ◽  
Gebhard Koch ◽  
Friedrich Lohss
Keyword(s):  
Escherichia Coli ◽  
Chemical Analysis ◽  
Cell Membrane ◽  
B Cell ◽  
Dry Weight ◽  
Shigella Sonnei ◽  
Receptor Activity ◽  
Escherichia Coli B

Dissociation in 90% phenol uncovers a layer of the Coli B-cell membrane showing the typical antiviral specificity of the receptor for phages T3, T4 and T7. Chemical analysis proved glucose, glucosamine and a yet unknown carbohydrate, probably a heptose, to be components of the receptor material, which amounts to about 13% of the dry weight of the whole membrane.Analogous material obtained from the membrane of B/3,4,7, a B-mutant resistant against phages T3, T4 and T7, has no activity against these phages and contains glucosamine and small amounts of glucose, but no heptose.In view of similar findings of Jesaitis and Goebel with T3,4,7 - receptor material from Shigella Sonnei, the rôle of the heptose as a characteristic and functionally indispensable component of lipocarbohydrates with receptor activity against T3, T4 and T7 is discussed.

scholarly journals The 503nm pigment of Escherichia coli

1970 ◽  
Vol 120 (4) ◽  
pp. 771-775 ◽  
Author(s):  
Joyce R. Kamitakahara ◽  
W. J. Polglase
Keyword(s):  
Escherichia Coli ◽  
B Cells ◽  
Cell Protein ◽  
Wild Type ◽  
E Coli ◽  
Aerobic Energy Metabolism ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Escherichia Coli B ◽  
Wild Type Parent

The yield of cell protein was one-third less for streptomycin-dependent Escherichia coli B than for the wild-type parent strain when both were grown aerobically on a medium with limiting glucose, but anaerobically the yield of protein was similar for both strains. The transient pigment absorbing at 503nm that is known to be present in E. coli and other organisms was not detectable in streptomycin-dependent mutants nor in a non-dependent (energy-deficient) revertant. When wild-type E. coli B was grown on limiting glucose–salts medium containing 2,4 dinitrophenol, the yield of cell protein was decreased and formation of the 503nm pigment was inhibited. Fumarase, aconitase and glucose 6-phosphate dehydrogenase were de-repressed in E. coli B cells grown with excess of glucose in a medium containing 2,4-dinitrophenol. In air-oxidized, wild-type E. coli B cells, the 503nm pigment appeared before reduced cytochromes when gluconate was the substrate but failed to appear when succinate was the substrate. The results provide evidence for a role of the 503nm pigment in aerobic energy metabolism, possibly as an electron acceptor from NADPH.

Sites of Adsorption of the Bacteriophages T3 and T5 on the Wall of Escherichia Coli B.

1967 ◽  
Vol 25 ◽  
pp. 96-97
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Electron Microscope ◽  
Uranyl Acetate ◽  
E Coli ◽  
Receptor Sites ◽  
Rigid Cell Wall ◽  
Host Cell Surface ◽  
Bacterial Viruses ◽  
Escherichia Coli B

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.

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