Cadmium accumulation, retention and sequestering by protein were measured in two Mycobacterium scrofulaceum strains differing in their susceptibility to that toxic heavy metal cation. Cadmium accumulation was energy-dependent and temperature-sensitive. The tolerant strain had lower K<sub>m</sub> and V<sub>max</sub> values than did the susceptible strain. Cd⁺² accumulation was antagonized by both Zn⁺² and Mn⁺², which agreed with the observation that both cations protected the strains from Cd⁺² toxicity. Further, Zn⁺² and Mn⁺² did not reduce Cd⁺² accumulation to the same extent in the tolerant strain as in the susceptible strain, suggesting that cadmium resulted in more extensive zinc and manganese starvation in the cadmium-susceptible strain. Cd⁺² was retained to the same extent in both the susceptible and tolerant strains by a Cd⁺²-specific, energy-dependent exchange mechanism. Thus, tolerance was not due to accelerated efflux. Though a cadmium-inducible, soluble protein was discovered only in the tolerant strain, its inability to bind Cd⁺² and exclusive production during the stationary phase of growth argued against its role in cadmium tolerance. / M.S.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/106099 |
| Date | January 1986 |
| Creators | Erardi, Francis X. |
| Contributors | Microbiology |
| Publisher | Virginia Polytechnic Institute and State University |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | vii, 74 leaves, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 15554583 |
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