title: [Riboflavin overproduction in 4-aminopyrazole[3,4-d]pyrimidine-treated yeast Pichia guilliermondii].
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.
authors.affiliation: Institute of Cell Biology, National Academy of Sciences of Ukraine, ul. Dragomanova 14/16, Lviv, 79005 Ukraine. vasylkutsiaba@yahoo.com
authors.forename: V I
authors.initials: VI
authors.lastname: Kutsiaba
authors.forename: N N
authors.initials: NN
authors.lastname: Stenchuk
authors.forename: D V
authors.initials: DV
authors.lastname: Fedorovich
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D001375:Azaguanine / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D016296:Mutagenesis; D010843:Pichia / Q000187:drug effects* / Q000378:metabolism; D011687:Purines / Q000096:biosynthesis; D011743:Pyrimidines / Q000096:biosynthesis; D012256:Riboflavin / Q000096:biosynthesis / Q000378:metabolism*
chemical_list: D011687:Purines; D011743:Pyrimidines; C004420:4-aminopyrazolo(3,4-d)pyrimidine; D000225:Adenine; D001375:Azaguanine; D012256:Riboflavin; C030985:purine
vernacular_title: Sverkhsintez riboflavina u drozhzheĭ Pichia guilliermondii pri deĭstvii 4-aminopirazol[3,4-d]pirimidina.