Term of Award

Spring 2002

Degree Name

Master of Science

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Committee Chair

Sara Neville Bennett

Committee Member 1

Wayne A. Krissinger

Committee Member 2

Jonathan Copeland

Abstract

Genetic research was conducted using os-11 trp-1 double mutants in this study. Conidia from the double mutants were subjected to UV irradiation and os-11+ revertants were isolated. A total of 47 putative revertants were isolated in the study. Two of the putative revertants were crossed to double mutants. The cross Rev-2-4AX DA-2-68a exhibited a low viability at 8% and the second cross Rev-2-13XDA-60 had a viability of 22% for progeny. The revertants revealed the presence of the trp-1 a genetic marker. Recovery of os+ progeny indicated that the reversion was genetic.

Growth tests in the study measured osmotic sensitivity of the osmotic strains isolated in the Neurospora Genetics Laboratory at Georgia Southern University, os-8, os-9 (SS-462) os-9 (SS-788), os-10, and os-11, and compared their sensitivity to earlier reported strains os-1, os-2, os-4, and os-5.

On medium with NaCl as the osmoticum the mutants os-8, os-9 (SS-462), os-9 (SS-788) and os-1 failed to grow at .684 osmolality; os-5 failed to grow ax 1.37 osmolality; os-10, os-11, os-2 failed to grow at 1.71 osmolality.

On medium with KC1 as the osmoticum the mutants os-1 and os-10 failed to grow at 1.03 osmolality; os-2, os-5 and os-8 failed to grow at 1.37 osmalality. os-11 failed to grow at 2.05 osmalality and os-4 failed to grow at 2.74 osmolality The two alleles of os-9 were less sensitive. The mutant os-9 (SS-788) failed to grow at 3.42 osmolality. The mutant os-9 (SS-462) was not sensitive at the concentrations of KC1 tested and grew at 3.42 osmolality.

On medium with glucose as the osmoticum the mutants, os-1 and os-2 failed to grow at .684 osmolality. The mutants 05-5 and os-10 failed to grow at 1.03 osolality; os-8 and os-11 failed to grow at 2.05 osmolality. Both alleles, SS-462 and SS-788, of os-9 failed to grow at 3.42 osmolality.

Thus, the two alleles of os-9 were sensitive on media supplemented with NaCl, but failed to show sensitivity on media with KC1 or glucose, as the osmoticum. This suggests that the sensitivity of os-9 might be specific for NaCl.

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