Characterization of Cadmium susceptibility in Mycobacterium avium, Mycobacterium intracellulare and Mycobacterium scrofulaceum

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_m and V_max 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.

Name thesis:degree_name

M.S.

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Microbiology

Department dc:contributor.department

Microbiology

Grantor dc:publisher

Virginia Polytechnic Institute and State University

Year dc:date.issued

1986

Author dc:creator

• Erardi, Francis X.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/10919/106099

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/106099