Mutants of escherichia coli requiring methionine or vitamin b12
TLDR
Certain biochemical properties of auxotrophicl mutants of Escherichia coli with specific growth requirements for most of the known water-soluble vitamins, as well as of others responding to methionine but not to B,2 are described.Abstract:
The penicillin method (Davis, 1948; Lederberg and Zinder, 1948) has permitted convenient isolation of auxotrophicl mutants of Escherichia coli with specific growth requirements for most of the known water-soluble vitamins, as well as amino acids, purines, and pyrimidines. Accordingly, when crystalline vitamin B12 became available, a search was made for mutants requiring this nutrilite. Several strains of the desired type were promptly recovered. In all cases methionine, but not homocysteine, could be substituted for the vitamin. This paper describes certain biochemical properties of these mutants, as well as of others responding to methionine but not to B,2.read more
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References
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A microbiological method for the determination of choline by use of a mutant of Neurospora
N. H. Horowitz,G. W. Beadle +1 more
TL;DR: It is shown that the Neurospora mutant is a suitable test organism in a quantitative assay for choline and form the basis of a simple, sensitive, and specific method for the determination of choline in natural products.
Journal ArticleDOI
Studies on nutritionally deficient bacterial mutants isolated by means of penicillin
Journal ArticleDOI
Methionine synthesis in neurospora. the isolation of cystathionine
TL;DR: Among artificially produced biochemical mutants of Neurospora, those which have lost the ability to synthesize methionine form the largest class, and some of the mutants require organically bound sulfur for growth, an indication that in these strains the block in methamphetamineionine synthesis comes at a later stage than sulfate reduction.