Genetics: Fricke and Demerec

The genetic homology of Salmonella typhimurium and Escherichia coli.

H Y B R I D S of enteric bacteria have been useful for various purposes which include the mapping of regions of the Salmonella typhimurium chromosome which are larger than transducing fragments but too short for convenient timeof-entry mapping (DEMEREC l964,1965a,b; DEMEREC and OHTA 1964; GLATZER, LABRIE and ARMSTRONG 1966; ARMSTRONG 1967). Hybrids have also been employed to determine the genet...

Proline Mutants of Salmonella Typhimurium.

CCORDING to previous analyses of 16 proline-requiring mutants of SalmonA d l a typhimurium, made genetically by NIELSEN (DEMEREC et al. 1954) and biochemically by JSANAZIR (1956; DEMEREC et al. 1955), the mutants fell into at least three groups. Recently, the number of proline-requiring mutants in our collection was increased to more than 200, and useful new techniques were devised or adapted f...

A proposal for a uniform nomenclature in bacterial genetics.

Ditto deletions in the cysC region of the Salmonella chromosome.

PREVIOUS studies have revealed that the cysC region of the Salmonella typhimurium chromosome includes a cluster of five genes arranged in the sequence cysC-D-H-I-J ( MIZOBUCHI, DEMEREC and GILLESPIE 1962). Genes cysC and D are adjacent to each other, as are genes I and J (Figure 1). Genes D and H are separated by a long segment of genetic material for which no functions have been found (the “si...

Isoleucine-valine Requiring Mutants of Salmonella Typhimurium.

initial reports on the mutant strains of Salmonella typhimurium that T: eui r both isoleucine and valine for growth (ilva strains) were published concomitantly by GLANVILLE and DEMEREC ( 1960) and WAGNER and BERGQUIST (1960). These studies showed that although the available ilva strains could be divided into four complementation groups ( A , B , C and D ) on the basis of abortive transduction r...