Leucocin A is a class 11a bacteriocin produced by Leuconostoc mesenteroides TA33a that was
previously shown to inhibit Listeria monocytogenes. A spontaneous resistant mutant of
L. monocytogenes was isolated, and found to be resistant to leucocin A at levels in excess of
2 mg/ml. The resistant mutant had an eight-fold increased binding capacity for leucocin A in
comparison to the parental strain. The mutant showed no significant cross resistance to nisaplin
or ESFI-7GR. The resistant phenotype had a similar growth rate in monoculture, to the sensitive
phenotype. DNA and protein analysis of the resistant and susceptible strains were carried out
using silver stained amplified fragment length polymorphism (ssAFLP) and one and two dimensional
(2D) SDS polyacrylamide gel electrophoresis (PAGE). Two-dimensional SDS
PAGE revealed two differences. The first was a 35 kDa protein which was present in the
sensitive but absent from the resistant phenotype and, secondly there was a higher level of
expression of a 18 kDa protein in the resistant phenotype compared with the sensitive phenotype.
The 35 kDa protein was found to have a 83% homology to the mannose-specific
phosphotransferase system IIAB of Streptococcus salivarius. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2000.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/9794 |
| Date | 21 October 2013 |
| Creators | Ramnath, Manilduth. |
| Contributors | Hastings, John W. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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