Isolation and characterization of selenate resistant mutants of Acremonium chrysogenum
Mutants unable to convert exogenous sulfate to sulfite were isolated using the toxic analogue selenate. Three of twenty-eight isolated mutants were chromate sensitive. They showed a possible lesion in the gene that codes the ATP sulfurylase. The others were chromate resistant, and probably had a lesion in one or both of the genes that code the sulfate permease. Methionine increased the resistance levels to selenate. In addition, the frequency of spontaneous mutants obtained in a medium containing methionine was higher (between 2.4 x 10-6 and 18.0 x 10-6) than that obtained using a medium without any intentional source of sulfur (between 0.7 x 10-6 and 5.0 x 10-6). The original strain, as well as the mutants, were able to grow in a sulfur-free liquid medium even after 4 consecutive inoculation procedures. These results indicated the existence of sulfur traces in the medium and/or an efficient intracellular storage system. There was no significant difference between cephalosporin C production in mutants and the original strain.
| Main Authors: | , , , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Instituto de Tecnologia do Paraná - Tecpar
1999
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| Online Access: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89131999000300016 |
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