It was demonstrated that induction of a major outer
protein, HI, was associated with increased resistance to
chelators of divalent cations such as EDTA and to the cationic
antibiotics polymyxins and aminoglycosides. Outer membrane
protein HI was the major cellular protein in cells grown in
Mg²⁺-deficient medium (0.02 mM Mg²⁺) and in mutants selected for
resistance to polymyxin. Increase in protein HI was associated
with decrease in cell envelope Mg²⁺. Induction of protein HI
was prevented by supplementation of Mg²⁺-deficient medium with
0.5 mM Mg²⁺, Ca²⁺, Mn²⁺ or Sr²⁺, but not by Zn²⁺, Ba²⁺, or
Sn²⁺. Cells grown in Ca²⁺, Mn²⁺ or Zn²⁺ showed enhanced levels
of these cations as main major cell envelope associated cation.
Only cells grown in the presence of those cations which failed
to prevent HI induction were resistant to chelators, polymyxin B
and gentamicin. Protein HI overproducing cells also
demonstrated altered streptomycin uptake.
It was further demonstrated that aminoglycosides could
interact with the outer membrane so as to make it more permeable
to other substances. Mg²⁺ inhibited aminoglycoside-mediated
permeabilization. Both aminoglycosides and polymyxin B could be
shown to displace a small amount of Mg²⁺ from the cell envelope. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/23663 |
| Date | January 1982 |
| Creators | Nicas, Thalia Ioanna |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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