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Selection of ura5 and ura3 mutants from the two varieties of Cryptococcus neoformans on 5-fluoroorotic acid medium.
J Med Vet Mycol. 1992; 30(1):61-9.JM

Abstract

Spontaneous mutants requiring uracil were isolated from both varieties of Cryptococcus neoformans by plating on 5-fluoroorotic acid (5-FOA) medium. Of the 36 strains tested (18 var. neoformans and 18 var. gattii), 24 (12 of each variety) generated 5-FOA-resistant cells requiring uracil for growth. Six of the 12 C. neoformans var. gattii strains produced ura3 cells while the remaining six strains produced ura5 cells. None of the 12 strains produced both ura3 cells and ura5 cells. All 12 isolates of var. neoformans, however, produced ura5 cells and one of them produced ura3 as well as ura5 cells. A genetic lesion in the URA5 gene of an isolate of C. neoformans var. gattii was confirmed by complement with the cognate URA5 gene of C. neoformans var. neoformans. The ura3 isolates were tentatively identified by their ability to grow on a medium containing uridine but not on a medium with orotic acid or orotidine. Enzymatic assays for orotidine-5'-phosphate decarboxylase activity confirmed the isolates to be ura3 mutants. Hybridization analysis of total DNA, digested with EcoRI or StuI and probed with pURA5g2, revealed the presence of only one copy of URA5 in the strains of either variety, regardless of the prevalence of ura5 mutants. Extensive polymorphism was observed in the restriction patterns of the fragments containing the URA5 locus. The prevalence of spontaneously arising ura3 mutants among the isolates of C. neoformans var. gattii, but not among the isolates of C. neoformans var. neoformans, is one more biological difference that distinguishes the two varieties.

Authors+Show Affiliations

Kwon-Chung KJ
Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892.
Varma A
No affiliation info available
Edman JC
No affiliation info available
Bennett JE
No affiliation info available

MeSH

AnimalsBlotting, SouthernCryptococcus neoformansCulture MediaDNA, FungalDeoxyribonuclease EcoRIDeoxyribonucleases, Type II Site-SpecificHumansMutationNucleic Acid HybridizationOrotic AcidOrotidine-5'-Phosphate DecarboxylaseRestriction MappingTransformation, GeneticUracilUridine

Pub Type(s)

Journal Article

Language

eng

PubMed ID

1573522

Citation

Kwon-Chung, K J., et al. "Selection of Ura5 and Ura3 Mutants From the Two Varieties of Cryptococcus Neoformans On 5-fluoroorotic Acid Medium." Journal of Medical and Veterinary Mycology : Bi-monthly Publication of the International Society for Human and Animal Mycology, vol. 30, no. 1, 1992, pp. 61-9.
Kwon-Chung KJ, Varma A, Edman JC, et al. Selection of ura5 and ura3 mutants from the two varieties of Cryptococcus neoformans on 5-fluoroorotic acid medium. J Med Vet Mycol. 1992;30(1):61-9.
Kwon-Chung, K. J., Varma, A., Edman, J. C., & Bennett, J. E. (1992). Selection of ura5 and ura3 mutants from the two varieties of Cryptococcus neoformans on 5-fluoroorotic acid medium. Journal of Medical and Veterinary Mycology : Bi-monthly Publication of the International Society for Human and Animal Mycology, 30(1), 61-9.
Kwon-Chung KJ, et al. Selection of Ura5 and Ura3 Mutants From the Two Varieties of Cryptococcus Neoformans On 5-fluoroorotic Acid Medium. J Med Vet Mycol. 1992;30(1):61-9. PubMed PMID: 1573522.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Selection of ura5 and ura3 mutants from the two varieties of Cryptococcus neoformans on 5-fluoroorotic acid medium. AU - Kwon-Chung,K J, AU - Varma,A, AU - Edman,J C, AU - Bennett,J E, PY - 1992/1/1/pubmed PY - 1992/1/1/medline PY - 1992/1/1/entrez SP - 61 EP - 9 JF - Journal of medical and veterinary mycology : bi-monthly publication of the International Society for Human and Animal Mycology JO - J Med Vet Mycol VL - 30 IS - 1 N2 - Spontaneous mutants requiring uracil were isolated from both varieties of Cryptococcus neoformans by plating on 5-fluoroorotic acid (5-FOA) medium. Of the 36 strains tested (18 var. neoformans and 18 var. gattii), 24 (12 of each variety) generated 5-FOA-resistant cells requiring uracil for growth. Six of the 12 C. neoformans var. gattii strains produced ura3 cells while the remaining six strains produced ura5 cells. None of the 12 strains produced both ura3 cells and ura5 cells. All 12 isolates of var. neoformans, however, produced ura5 cells and one of them produced ura3 as well as ura5 cells. A genetic lesion in the URA5 gene of an isolate of C. neoformans var. gattii was confirmed by complement with the cognate URA5 gene of C. neoformans var. neoformans. The ura3 isolates were tentatively identified by their ability to grow on a medium containing uridine but not on a medium with orotic acid or orotidine. Enzymatic assays for orotidine-5'-phosphate decarboxylase activity confirmed the isolates to be ura3 mutants. Hybridization analysis of total DNA, digested with EcoRI or StuI and probed with pURA5g2, revealed the presence of only one copy of URA5 in the strains of either variety, regardless of the prevalence of ura5 mutants. Extensive polymorphism was observed in the restriction patterns of the fragments containing the URA5 locus. The prevalence of spontaneously arising ura3 mutants among the isolates of C. neoformans var. gattii, but not among the isolates of C. neoformans var. neoformans, is one more biological difference that distinguishes the two varieties. SN - 0268-1218 UR - https://www.unboundmedicine.com/medline/citation/1573522/Selection_of_ura5_and_ura3_mutants_from_the_two_varieties_of_Cryptococcus_neoformans_on_5_fluoroorotic_acid_medium_ DB - PRIME DP - Unbound Medicine ER -