Accession Number : AD0631205

Title :   POTASSIUM TRANSPORT MUTANT OF ESCHERICHIA COLI B. ANALYSIS OF POTASSIUM MOVEMENTS.

Descriptive Note : Rept. for Jun 64-Dec 65,

Corporate Author : SCHOOL OF AEROSPACE MEDICINE BROOKS AFB TEX

Personal Author(s) : Damadian,Raymond

Report Date : FEB 1966

Pagination or Media Count : 20

Abstract : A second mutant of Escherichia coli B (strain RD-2) with impaired K transport was isolated with nitroguanidine as the mutagenic agent. Except for its K requirement, RD-2 manifests the same nutritional requirements as the parent strain and contrasts with RD-1, which was shown to be deficient both in K transport and in methionine biosynthesis. RD-2 will not grow in a low K media (20 micro M. K) which supports growth of the parent strain. Electron microscopic examination of the two strains reveals no differences in surface layer ultrastructure to account for the transport impairment. Potassium accumulation studies demonstrate that the mutant low K growth failure is attributable to a K accumulation impairment. In contrast to the parent strain, RD-2 cannot accumulate K from the low K media. Addition of K to a nonaccumulating low K suspension of RD-2 stimulates uptake of K, thus establishing viability of the cells. Measurement of low K steady-state tracer fluxes yields flux values for RD-2, which are one-third those of the parent strain, and the calculated influx rate constants are consistent with the interpretation that RD-2's accumulation failure is due to an influx impairment. (Author)

Descriptors :   (*POTASSIUM, OSMOSIS), (*ESCHERICHIA, CELL STRUCTURE), (*CELL STRUCTURE, TRANSPORT), MUTATIONS, DISTRIBUTION, ELECTRON MICROSCOPY, BIOSYNTHESIS, METHIONINE, MOTION, ELECTROLYTES(PHYSIOLOGY)

Subject Categories : Microbiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE