Cation exchange in cell walls of gram-positive bacteria
| Autor: | Kathleen Mayzel, Edwin L. Carstensen, Robert E. Marquis |
|---|---|
| Rok vydání: | 1976 |
| Předmět: |
Staphylococcus aureus
Gram-positive bacteria Immunology Applied Microbiology and Biotechnology Microbiology Bacterial cell structure Micrococcus Streptococcus mutans Species Specificity Cell Wall Enterococcus faecalis Genetics Magnesium Displacement (orthopedic surgery) Molecular Biology Chromatography Bacteria biology Chemistry Sodium General Medicine biology.organism_classification Affinities Ion Exchange Bacillus megaterium Potassium Biophysics Calcium |
| Zdroj: | Canadian Journal of Microbiology. 22:975-982 |
| ISSN: | 1480-3275 0008-4166 |
| DOI: | 10.1139/m76-142 |
| Popis: | The relative affinities of various cations for anionic sites in isolated, bacterial cell walls were assessed by means of a technique involving displacement of one cation by another. The affinity series determined was [Formula: see text]. High affinity was correlated with low mobility of the bound ions in an electric field. The net cation-exchange capacities of walls isolated from a variety of bacteria were estimated by preparing the magnesium forms of the walls, washing them well with deionized water to remove supernumerary ions, and then completely displacing the magnesium with Na+ or H+. Total amounts of magnesium displaced varied from 73 μmol per gram dry weight, for walls of the teichoic acid-deficient 52A5 strain of Staphylococcus aureus to about 520 μmol per gram for Bacillus megaterium KM walls. The amount of displacable magnesium was inversely related to the physical compactness of the walls, except for walls of Streptococcus mutans GS-5. It was found that magnesium or calcium ions can each neutralize, or pair with, two anionic groups in walls suspended in ion-deficient media. Previous work had indicated that these ions may pair with only one anionic group at high ionic strength. Therefore, it appeared that there is a great deal of flexibility in the arrangement of charged groups in the wall. It was concluded also that for cells growing in commonly used laboratory media, which generally contain large excesses of monovalent versus divalent cations, there is a mix of small, cationic counterions in the wall and that monovalent cations may predominate even though the wall has higher affinity for divalent ions. |
| Databáze: | OpenAIRE |
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