scholarly journals Iodinated vancomycin and mucopeptide biosynthesis by cell-free preparations from Micrococcus lysodeikticus

1970 ◽  
Vol 119 (5) ◽  
pp. 877-883 ◽  
Author(s):  
Claudette Bordet ◽  
H. R. Perkins
Keyword(s):  
Cell Wall ◽  
Binding Sites ◽  
Complete Inhibition ◽  
Micrococcus Lysodeikticus ◽  
Insoluble Part ◽  
Insoluble Portion

A particulate preparation from Micrococcus lysodeikticus was used to synthesize cell-wall mucopeptide. Radioactive iodinated vancomycin became attached to the preparation simultaneously with a complete inhibition of mucopeptide synthesis. After mucopeptide synthesis had occurred in the absence of antibiotic, the preparation took up more vancomycin, suggesting that new binding sites terminating in acyl-d-alanyl-d-alanine had been produced. The mucopeptide product was divided into a soluble and an insoluble portion, both sensitive to lysozyme. The soluble portion did not combine with vancomycin and hence had presumably lost its terminal d-alanine residues, either by transpeptidation or because of carboxy-peptidase action. The synthesis of both portions was unaffected by the presence of penicillin, but the insoluble part showed increased affinity for vancomycin, thus indicating that penicillin had caused conservation of d-alanyl-d-alanine termini.

EFFECT OF ALKYL BENZENE SULPHONATE ON YEAST METABOLISM

1963 ◽  
Vol 9 (1) ◽  
pp. 117-127
Author(s):  
E. R. Blakley
Keyword(s):  
Cell Wall ◽  
Candida Utilis ◽  
Complete Inhibition ◽  
Enzymatic Reactions ◽  
Alkyl Benzene ◽  
Intact Cells ◽  
Yeast Metabolism ◽  
Ph Values ◽  
Upper Limit ◽  
Yeast Protoplasts

The rate of fermentation of glucose by suspensions of Candida utilis at acid pH values is reduced by alkyl benzene sulphonate in the range 75 to 250 γ/ml. Concentrations of alkyl benzene sulphonate below 75 γ/ml decrease the rate of fermentation of glucose above pH 7 and respiration at all pH values. An upper limit of 70 to 90% inhibition of fermentation or respiration is obtained at concentrations of alkyl benzene sulphonate above 250 γ/ml, except at pH 4.2 where complete inhibition is obtained. The effect of alkyl benzene sulphonate on the fermentation of glucose by yeast protoplasts is similar to the effect observed for intact yeasts. Some enzymatic reactions of cell-free extracts are inhibited by concentrations of alkyl benzene sulphonate lower than that required to affect fermentation by intact cells. The enzyme components of the cell-free preparation appear to vary in their sensitivity to the surfactant. The results support the view that the surfactant in the micellar form disrupts the cell wall of the yeast, and unassociated molecules inactivate some enzymes vital for the metabolism of the cell.

THE MODE OF ACTION OF THE ANTIBIOTIC PAROMOMYCIN ON STAPHYLOCOCCUS AUREUS

1966 ◽  
Vol 12 (6) ◽  
pp. 1157-1165 ◽  
Author(s):  
A. von Seefried ◽  
D. C. Jordan
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Binding Sites ◽  
Bactericidal Action ◽  
Plate Method ◽  
Vitro Binding ◽  
Resistant Mutants ◽  
Intracellular Binding

Paromomycin (Humatin, Parke Davis & Co.), a broad-spectrum aminoglycosidic antibiotic, inhibits the incorporation of amino acids into the trypsinsoluble protein fraction of Staphylococcus aureus 257. Protein synthesis is inhibited immediately, but the synthesis of cell-wall mucopeptide and alcohol-soluble proteins and lipids is not affected for approximately 35 min after antibiotic addition to actively growing cells. Paromomycin, at the ribosomal level, prevents the attachment of amino acyl-s-RNA and causes accumulation of m-RNA.Divalent cations (Ca++ and Mg++) antagonize the bactericidal action of paromomycin and interfere with the in vivo binding of the antibiotic on both the cell surface and the intracellular binding sites. In vitro binding to free ribosomes can be prevented and reversed by both monovalent and divalent cations.Using a "cylinder-plate" method, involving the displacement of antibiotic from cellular fractions by 0.2 M MgCl2, the antibiotic can be recovered from the ribosomes, cytoplasm, and the cell wall of paromomycin-sensitive S. aureus cells, but is not found in any of these fractions isolated from paromomycin-resistant cells developed from the sensitive parent strain. The resistant mutants apparently have lost the ability to adsorb and transport the antibiotic into the cell.

Nutritional requirements for cell wall synthesis in Micrococcus lysodeikticus

1969 ◽  
Vol 15 (4) ◽  
pp. 327-334
Author(s):  
M. P. Hatton
Keyword(s):  
Amino Acids ◽  
Cell Wall ◽  
Glutamic Acid ◽  
Dry Weight ◽  
Defined Medium ◽  
Complete Medium ◽  
Magnesium Ions ◽  
Cell Wall Synthesis ◽  
Micrococcus Lysodeikticus ◽  
Total Dry Weight

Preferential cell wall synthesis in Micrococcus lysodeikticus, as determined by an increase in the dry weight of the cell wall, took place in a medium containing DL-glutamic acid, DL-alanine, L-lysine, glycine, magnesium ions, glucose and phosphate buffer, pH 7.0. Cell wall synthesis could not be completely dissociated from protein synthesis in the 'cell wall' medium. The cell wall synthesized in the defined medium accounted for 40–56% of the total dry weight increase of the cells. Chloramphenicol had no effect on cell wall synthesis. Incorporation of uracil and guanine in the medium did not result in any increase in the amount of cell wall synthesized. DL-Glutamic acid alone, or a mixture of the three amino acids DL-alanine, L-lysine, and glycine, were capable of replacing the four amino acids present in the complete medium, but under these conditions the total dry weight of cell wall synthesized was only 75% of that produced in the complete medium. There was no reduction in cell wall synthesis when L-glutamic acid replaced DL-glutamic acid, L-alanine replaced DL-alanine, or sucrose replaced glucose in the cell wall medium. Deprivation of magnesium ions produced the greatest decrease in wall synthesis; this was the most important single factor involved in cell wall synthesis which was studied in the present investigation. There was no observable change in the chemical composition of the cell wall synthesized in the 'wall' medium when compared to that synthesized by cells grown in a complex medium.

scholarly journals Interaction of the Crystalline Bacterial Cell Surface Layer Protein SbsB and the Secondary Cell Wall Polymer of Geobacillus stearothermophilus PV72 Assessed by Real-Time Surface Plasmon Resonance Biosensor Technology

2004 ◽  
Vol 186 (6) ◽  
pp. 1758-1768 ◽  
Author(s):  
Christoph Mader ◽  
Carina Huber ◽  
Dieter Moll ◽  
Uwe B. Sleytr ◽  
Margit Sára
Keyword(s):  
Cell Wall ◽  
Surface Plasmon Resonance ◽  
Real Time ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Binding Sites ◽  
Secondary Cell Wall ◽  
Sensor Chip ◽  
Geobacillus Stearothermophilus ◽  
Secondary Cell Wall Polymer

ABSTRACT The interaction between S-layer protein SbsB and the secondary cell wall polymer (SCWP) of Geobacillus stearothermophilus PV72/p2 was investigated by real-time surface plasmon resonance biosensor technology. The SCWP is an acidic polysaccharide that contains N-acetylglucosamine, N-acetylmannosamine, and pyruvic acid. For interaction studies, recombinant SbsB (rSbsB) and two truncated forms consisting of either the S-layer-like homology (SLH) domain (3SLH) or the residual part of SbsB were used. Independent of the setup, the data showed that the SLH domain was exclusively responsible for SCWP binding. The interaction was found to be highly specific, since neither the peptidoglycan nor SCWPs from other organisms nor other polysaccharides were recognized. Data analysis from that setup in which 3SLH was immobilized on a sensor chip and SCWP represented the soluble analyte was done in accordance with a model that describes binding of a bivalent analyte to a fixed ligand in terms of an overall affinity for all binding sites. The measured data revealed the presence of at least two binding sites on a single SCWP molecule with a distance of about 14 nm and an overall K d of 7.7 × 10−7 M. Analysis of data from the inverted setup in which the SCWP was immobilized on a sensor chip was done in accordance with an extension of the heterogeneous-ligand model, which indicated the existence of three binding sites with low (K d = 2.6 × 10−5 M), medium (K d = 6.1 × 10−8 M), and high (K d = 6.7 × 10−11 M) affinities. Since in this setup 3SLH was the soluble analyte and the presence of small amounts of oligomers in even monomeric protein solutions cannot be excluded, the high-affinity binding site may result from avidity effects caused by binding of at least dimeric 3SLH. Solution competition assays performed with both setups confirmed the specificity of the protein-carbohydrate interaction investigated.

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