CGSC Strain#: 4230
Strain Designation: Hfr 44     
Source of Strain: P. Horn-Cooper
Sex: Hfr
Point of Origin#: 63
Map Position: 44.60
Direction of Marker Transfer: Counterclockwise
Chromosomal Markers: galT23,
λ-,
argS41,
argA42,
argR40,
ilv-282Strain Comments: - 1.It has not been possible to determine the exact derivation of this strain. The original argA- ancestor was either W3421 or W3422.
- 2.The strain is an arg bradytroph. The strain may still carry the original argA mutation (which was either argA21 or argA22) in addition to the mutation argA42,
- 3.which rendered it a bradytroph. It grows very slowly and stops at 4 x 108 cells/ml. It must be mated when growing exponentially at around 108/ml. It does not grow well on minimal plus
- 4.ARG plus ILV. We have received a report that it is helped by LYS plus a mixture of vitamins.
- galT23-- : This is the standard gal6 of Morse & Lederberg.
- argS41-- This allele has a C to A transition in the codon 134 leading to the substitution of an arginine by a serene residue.
References: - Cooper, PH, IN Hirshfield, WK Maas 1969. Map location of arginyl-tRNA synthetase mutations in Escherichia coli K-12. Mol. Gen. Genet. 104(4):383-90.