Elective Production of Thymine-less Mutants

Okada, Toshihiko; Yanagisawa, Keiji; Ryan, Francis J.

doi:10.1038/188340a0

Cited by 91 publications

(27 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Auxotrophic mutants requiring amino acid(s) and/or purines or pyrimidines were obtained from the survivors of UV-irradiated cells, or cells treated with 30 ,cig per ml of N-methyl-N'-nitro-Nnitrosoguanidine (NTG; Aldrich Chemicals, Wisconsin, U.S.A.) by a combination of penicillin screening and a replica-plating method [2,3]. Thymineless mutants were obtained by aminopterin-thymidine method of Okada et al [18]. Mutants of fermentative activity were scored from NTG-treated cells grown on nutrient agar plates to which 1% of a carbohydrate desired and 0.13', bromthymolblue had been added.…”

Section: Methodsmentioning

confidence: 99%

Genetic Recombination in Klebsiella pneumoniae An Approach to Genetic Linkage Mapping

Matsui

Tazaki

1970

Japanese Journal of Microbiology

View full text Add to dashboard Cite

show abstract

Section: Methodsmentioning

confidence: 99%

Genetic Recombination in Klebsiella pneumoniae An Approach to Genetic Linkage Mapping

Matsui

Tazaki

1970

Japanese Journal of Microbiology

View full text Add to dashboard Cite

show abstract

“…Thymine-requiring strains of Lactobacillus casei (Anton & Nichol, 1959) and Escherichia coZi (Okada, Yanagisawa & Ryan, 1960) have been obtained from amethopterin-inhibited cultures. However, the difficulties with regard to cellular transport of the structural analogues into folate auxotrophs, and the relative ease with which the small molecule antagonists are assimilated (Wood, Ferone & Hitchings, 1961) make the latter more useful inhibitors for the majority of microorganisms.…”

Section: Discussionmentioning

confidence: 99%

Resistance to Inhibitors of Dihydrofolate Reductase in Strains of Lactobacillus Casei and Proteus Vulgaris

Singer¹,

Elion²,

Hitchings³

1966

Journal of General Microbiology

View full text Add to dashboard Cite

SUMMARYStrains of Lactobacillus casei and Proteus vulgaris resistant to small molecule inhibitors of dihydrofolate reductase were isolated under various nutritional conditions. When thymine and/or purines were available in the media, several of the isolated strains had nutritional requirements for these metabolites, but resistant lines could still be isolated in their absence. Thus, the biochemical alteration accompanying resistance could be predetermined to a major extent by the design of the experiment.The wild-type strain of Proteus vulgaris did not incorporate exogenous thymine, and was insensitive to thymine antagonists, while the thyminerequiring strain was highly sensitive to 5-bromouracil, dithiothymine and 2-thiothymine. This suggested that resistance was accompanied by the appearance of a permeability or transport system for thymine.

show abstract

“…Thymine-requiring mutants of the strains listed in Table I were selected by the procedure of Okada, Yanagisawa & Ryan (1960). The bacteria were radioactively labelled by growing them at 37" with shaking in the glucose salts medium G.T.…”

Section: Methodsmentioning

confidence: 99%

Stability of DNA in Dark-repair Mutants of Escherichia coli B Treated with Nalidixic Acid

Grigg

1970

Journal of General Microbiology

View full text Add to dashboard Cite

SUMMARYBreakdown of DNA to acid-soluble fragments induced in strains of Escherichia coli B by nalidixic acid (10 ,ug./ml.) differed in linear rate according to the ability of the strain to repair DNA lesions. Strains which were exr (BS-2) and exr, uvr (BS-I) exhibited excessive DNA breakdown following nalidixic aeid treatment. The excision-defective uvr strains, BS-8, BS-12 and WWP-2 hcr, also degraded their DNA to acid-soluble fragments at a rate which initially was greater than that of the parental strain (E. coli B). This degradation was unaffected by the rad mutation. Removal of nalidixic acid from the system considerably lowered the rate of DNA breakdown. The responses to nalidixic acid and other agents potentiating DNA breakdown are compared.

show abstract

Elective Production of Thymine-less Mutants

Cited by 91 publications

References 7 publications

Genetic Recombination in Klebsiella pneumoniae An Approach to Genetic Linkage Mapping

Genetic Recombination in Klebsiella pneumoniae An Approach to Genetic Linkage Mapping

Resistance to Inhibitors of Dihydrofolate Reductase in Strains of Lactobacillus Casei and Proteus Vulgaris

Stability of DNA in Dark-repair Mutants of Escherichia coli B Treated with Nalidixic Acid

Contact Info

Product

Resources

About