Affiliation:
1. Pharmacy Department, Chelsea College of Science and Technology, University of London, London, England
Abstract
Five metallic cations (Fe
3+
, Cr
3+
, Ca
2+
, Mg
2+
, Mn
2+
; concentration range, 1.85 � 10
-4
to 37 � 10
-4
m
) were incorporated individually as chlorides into nutrient broth and agar media used for the recovery of phenol-treated
Escherichia coli
. The effects observed varied with the concentration and the ionic species. In nutrient agar, Fe
3+
and Cr
3+
were generally beneficial but were toxic at 37 � 10
-4
m
. Of the divalent ions tested, Ca
2+
and Mg
2+
usually gave higher counts in nutrient broth, except at a concentration of 9.25 � 10
-4
m
, whereas the effect of Mn
2+
was rather variable. Two possible explanations are suggested to explain these effects. Toxic materials may be removed from the media by the precipitates formed on the addition of Fe
3+
or Cr
3+
, or, in the case of the divalent ions, the integrity of the bacterial cell membranes may be maintained.
Publisher
American Society for Microbiology
Subject
General Pharmacology, Toxicology and Pharmaceutics,General Immunology and Microbiology,General Biochemistry, Genetics and Molecular Biology,General Medicine