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[Riboflavin overproduction in 4-aminopyrazole[3,4-d]pyrimidine-treated yeast Pichia guilliermondii]
V I Kutsiaba1, N N Stenchuk, D V Fedorovich
1Institute of Cell Biology, National Academy of Sciences of Ukraine, ul. Dragomanova 14/16, Lviv, 79005 Ukraine. vasylkutsiaba@yahoo.com
Abstract:
More than 90 mutants resistant to the adenine analogue 4-aminopyrazole[3,4-d]pyrimidine (4-APP), were isolated from a wild-type strain of yeast Pichia guilliermondii. Some of Appr mutants accumulated noticeable amounts of products absorbing at 260 nm in the culture medium, probably nucleotides and their derivatives. In comparison to the parent strain, the mutant Appr-27 synthesized greater amounts of xanthine and uracil suggesting the presence of defects in the regulation of de novo biosynthesis of purines and pyrimidines. The regulatory mutations rib80 and rib81 are known to cause riboflavin (RF) overproduction and derepression of RF-producing enzyme synthesis in P. guilliermondii. The mutant Appr-27 was crossed to the rib81 strain. The yield of RF biosynthesis in some meiotic segregants was significantly higher than that in segregants from the diploid rib81/RIB81. Apparently, rib81 and appr mutations were combined in single genome on the favorable genetic background. An increase in RF production was also found in strains with appr mutations induced directly in the genome of the RF oversynthesizing strain rib80 rib81. These results indicate that introduction of appr mutations into genome of P. guilliermondii can intensify their RF overproduction.
Insights
New yeast mutants resistant to 4-aminopyrazole[3,4-d]pyrimidine (4-APP) were discovered. These mutations can intensify riboflavin (RF) overproduction in Pichia guilliermondii.
Area of Science:
- Microbiology
- Biochemistry
- Genetics
Context:
- Yeast Pichia guilliermondii is a model organism for studying metabolic regulation.
- Understanding purine and pyrimidine biosynthesis is crucial for various biological processes.
- Riboflavin (RF) overproduction is a commercially important trait in yeast.
Purpose:
- To isolate and characterize mutants of Pichia guilliermondii resistant to 4-aminopyrazole[3,4-d]pyrimidine (4-APP).
- To investigate the effect of these 4-APP resistance mutations on purine and pyrimidine biosynthesis.
- To determine if 4-APP resistance mutations can enhance riboflavin (RF) overproduction.
Summary:
- Over 90 mutants resistant to 4-APP were isolated from P. guilliermondii.
- Mutant Appr-27 showed altered purine and pyrimidine biosynthesis, accumulating xanthine and uracil.
- Crossing Appr-27 with rib81 (a known RF overproducing mutant) resulted in enhanced RF yields, indicating synergistic effects.
Impact:
- The study identifies novel mutations that can significantly increase riboflavin production in P. guilliermondii.
- These findings have implications for metabolic engineering and industrial biotechnology for enhanced RF biosynthesis.
- The research sheds light on the complex regulatory networks governing purine, pyrimidine, and riboflavin metabolism in yeast.
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