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.

ELECTRON MICROSCOPY OF ALKALINE PHOSPHATASE OF ESCHERICHIA COLI

1966 ◽  
Vol 12 (4) ◽  
pp. 605-607 ◽  
Author(s):  
V. M. Kushnarev ◽  
T. A. Smirnova
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Alkaline Phosphatase ◽  
Cell Wall ◽  
Enzyme Activity ◽  
Electron Microscope ◽  
Inorganic Phosphate ◽  
E Coli

A method is described for determining the localization of alkaline phosphatase in the cells of E. coli B with the electron microscope. Enzyme activity, determined by deposition of inorganic phosphate, is located in the exterior layer of the cell wall.

Erzwungene Infektion einer phagenresistenten Mutante von Escherichia Coli B

1952 ◽  
Vol 7 (3) ◽  
pp. 145-148 ◽  
Author(s):  
Wolfhard Weidel
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Phage Particle ◽  
Resistant Cell ◽  
Close Packing ◽  
Surface Pattern ◽  
Phage Resistance ◽  
E Coli ◽  
Cell Mutation ◽  
Escherichia Coli B

The E. coli mutant B/2, resistant to phages T 2 in free suspension, could be infected with T 2 using a „close packing“ technique. The experiments indicate that the first, electrostatic step of phage adsorption is dispensable and can be circumvented, the second, enzymatic step taking place immediately under conditions of forced contact between phage particle and resistant cell. Mutation to phage resistance in this case seems to have altered nothing but the electrostatic surface pattern of the bacterial cell wall.

Mucopeptidhydrolasen in Escherichia coli B

1963 ◽  
Vol 18 (11) ◽  
pp. 956-964 ◽  
Author(s):  
H. Pelzer
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Enzymatic Degradation ◽  
Quantitative Method ◽  
Degradation Products ◽  
In Vivo Studies ◽  
Partial Purification ◽  
E Coli ◽  
Escherichia Coli B

A quantitative method for the estimation of cell wall mucopeptides and their enzymatic degradation products by paper chromatography is described. The procedure can be used for measuring the activities of mucopeptidehydrolases as well as for in vivo studies of the metabolism of cell wall mucopeptides.A partial purification of E. coli mucopeptidehydrolases was achieved by column chromatography on DEAE-Sephadex.

Role of lipopolysaccharide in adsorption of coliphage T4D to Escherichia coli B

1976 ◽  
Vol 22 (5) ◽  
pp. 745-751 ◽  
Author(s):  
Takashi Watanabe
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Concanavalin A ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Diaminopimelic Acid ◽  
Receptor Sites ◽  
Heat Treated ◽  
Phage Receptor ◽  
Escherichia Coli B

Coliphage T4D was strongly adsorbed to intact lipopolysaccharides and alkaline and lipase-treated lipopolysaccharides from cells of Escherichia coli B, but was not so adsorbed to heat-treated cells. In contrast, coliphage T2h was not adsorbed to lipopolysaccharides and the heat-treated cells.Acid hydrolysate of lipopolysaccharides strongly inhibited the adsorption of phage T4D to acetone and ether-treated cells. The adsorption of phage T4D to the acetone and ether-treated cells was markedly inhibited by authentic D-glucosamine, N-acetyl-D-glucosamine, α-methyl-N-acetyl-D-glucosaminide, α-methyl-D-glucoside, and D-maltose. Authentic D-glucose and D,L-2,6-diaminopimelic acid also showed similar activity. These compounds did not affect the adsorption of phage T2h to the acetone- and ether-treated cells. Concanavalin A and wheat-germ agglutinin inhibited phage T4D adsorption to the acetone and ether-treated cells probably by blocking the phage-receptor sites on the cell wall. The blocking by concanavalin A and by wheat-germ agglutinin was reversed by α-methyl-D-glucoside and by α-methyl-N-acetyl-D-glucosaminide, respectively. Results suggested the possibility that coliphage T4D requires N-acetyl-D-glucosaminyl-glucose or glucosyl-D-glucosamine residues of the core of lipopolysaccharides for the initial attachment to the cell wall of Escherichia coli B.

scholarly journals Escherichia coli Mutants Lacking All Possible Combinations of Eight Penicillin Binding Proteins: Viability, Characteristics, and Implications for Peptidoglycan Synthesis

1999 ◽  
Vol 181 (13) ◽  
pp. 3981-3993 ◽  
Author(s):  
Sylvia A. Denome ◽  
Pamela K. Elf ◽  
Thomas A. Henderson ◽  
David E. Nelson ◽  
Kevin D. Young
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Binding Proteins ◽  
Kanamycin Resistance ◽  
Open Reading Frames ◽  
Penicillin Binding Proteins ◽  
E Coli ◽  
Peptidoglycan Biosynthesis ◽  
Kanamycin Resistance Cassette ◽  
Genes Encoding

ABSTRACT The penicillin binding proteins (PBPs) synthesize and remodel peptidoglycan, the structural component of the bacterial cell wall. Much is known about the biochemistry of these proteins, but little is known about their biological roles. To better understand the contributions these proteins make to the physiology ofEscherichia coli, we constructed 192 mutants from which eight PBP genes were deleted in every possible combination. The genes encoding PBPs 1a, 1b, 4, 5, 6, and 7, AmpC, and AmpH were cloned, and from each gene an internal coding sequence was removed and replaced with a kanamycin resistance cassette flanked by two ressites from plasmid RP4. Deletion of individual genes was accomplished by transferring each interrupted gene onto the chromosome of E. coli via λ phage transduction and selecting for kanamycin-resistant recombinants. Afterwards, the kanamycin resistance cassette was removed from each mutant strain by supplying ParA resolvase in trans, yielding a strain in which a long segment of the original PBP gene was deleted and replaced by an 8-bpres site. These kanamycin-sensitive mutants were used as recipients in further rounds of replacement mutagenesis, resulting in a set of strains lacking from one to seven PBPs. In addition, thedacD gene was deleted from two septuple mutants, creating strains lacking eight genes. The only deletion combinations not produced were those lacking both PBPs 1a and 1b because such a combination is lethal. Surprisingly, all other deletion mutants were viable even though, at the extreme, 8 of the 12 known PBPs had been eliminated. Furthermore, when both PBPs 2 and 3 were inactivated by the β-lactams mecillinam and aztreonam, respectively, several mutants did not lyse but continued to grow as enlarged spheres, so that one mutant synthesized osmotically resistant peptidoglycan when only 2 of 12 PBPs (PBPs 1b and 1c) remained active. These results have important implications for current models of peptidoglycan biosynthesis, for understanding the evolution of the bacterial sacculus, and for interpreting results derived by mutating unknown open reading frames in genome projects. In addition, members of the set of PBP mutants will provide excellent starting points for answering fundamental questions about other aspects of cell wall metabolism.

scholarly journals Modification by an R determinant for streptomycin of hissd phenotype in a mutant strain of Escherichia coli B

1968 ◽  
Vol 12 (2) ◽  
pp. 109-116 ◽  
Author(s):  
A. M. Molina ◽  
L. Calegari ◽  
G. Conte
Keyword(s):  
Escherichia Coli ◽  
Cell Membrane ◽  
Mutant Strain ◽  
Minimal Medium ◽  
Specific Requirement ◽  
Resistance Level ◽  
E Coli ◽  
Level Characteristic ◽  
Escherichia Coli B

When an R determinant for streptomycin is transferred into a conditionally streptomycin-dependent E. coli B mutant—which requires in minimal medium either histidine or streptomycin—the latter behaves like a histidineless strain. This phenotype modification shows that the repairing action of streptomycin is prevented. The specific requirement of the strain is not now replaced even by streptomycin concentrations up to 10000 µg/ml at which the conditionally streptomycin-dependent mutant could originally grow, and which are well beyond the resistance level characteristic of the R determinant itself. These data seem to suggest that a reduction in permeability of the cell membrane cannot be held responsible for the phenomenon observed.

Analysis of the Crushing Effect about Ultrasound on E. coli and B. subtilis

2012 ◽  
Vol 260-261 ◽  
pp. 1017-1021
Author(s):  
Xin Ying Wang ◽  
Yong Tao Liu ◽  
Min Hui ◽  
Ji Fei Xu
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Bacillus Subtilis ◽  
Bacterial Cell ◽  
Logarithmic Phase ◽  
Growth Stages ◽  
Bacterial Cells ◽  
E Coli ◽  
Different Growth Stages ◽  
Main Factor

Escherichia coli and Bacillus subtilis as objects of the study, ultrasonic fragmentation acted on the bacterial cells in different growth stages, results showed that, it’s similar to the crushing effect of ultrasound on E. coli and B. subtilis cells of different growth stages, the highest crushing rate in the logarithmic phase, reached to 95.8% and 94.3% respectively, the crushing rate of adjustment phase is lowest, maintained at around 60%, the crushing rate stability cell was centered, which can be achieved 90%. The structure of the bacterial cell wall didn’t the main factor to decide the ultrasonic fragmentation effect, but different growth periods of bacterial cells did the determinant.

scholarly journals The Transcriptional Factors MurR and Catabolite Activator Protein Regulate N-Acetylmuramic Acid Catabolism in Escherichia coli

2008 ◽  
Vol 190 (20) ◽  
pp. 6598-6608 ◽  
Author(s):  
Tina Jaeger ◽  
Christoph Mayer
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Sole Source ◽  
Lag Phase ◽  
Face To Face ◽  
E Coli ◽  
Catabolite Activator Protein ◽  
Activator Protein ◽  
High Level ◽  
First Time

ABSTRACT The MurNAc etherase MurQ of Escherichia coli is essential for the catabolism of the bacterial cell wall sugar N-acetylmuramic acid (MurNAc) obtained either from the environment or from the endogenous cell wall (i.e., recycling). High-level expression of murQ is required for growth on MurNAc as the sole source of carbon and energy, whereas constitutive low-level expression of murQ is sufficient for the recycling of peptidoglycan fragments continuously released from the cell wall during growth of the bacteria. Here we characterize for the first time the expression of murQ and its regulation by MurR, a member of the poorly characterized RpiR/AlsR family of transcriptional regulators. Deleting murR abolished the extensive lag phase observed for E. coli grown on MurNAc and enhanced murQ transcription some 20-fold. MurR forms a stable multimer (most likely a tetramer) and binds to two adjacent inverted repeats within an operator region. In this way MurR represses transcription from the murQ promoter and also interferes with its own transcription. MurNAc-6-phosphate, the substrate of MurQ, was identified as a specific inducer that weakens binding of MurR to the operator. Moreover, murQ transcription depends on the activation by cyclic AMP (cAMP)-catabolite activator protein (CAP) bound to a class I site upstream of the murQ promoter. murR and murQ are divergently orientated and expressed from nonoverlapping face-to-face (convergent) promoters, yielding transcripts that are complementary at their 5′ ends. As a consequence of this unusual promoter arrangement, cAMP-CAP also affects murR transcription, presumably by acting as a roadblock for RNA polymerase.

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