Inactivation of membrane transport in Escherichia coli by near-ultraviolet light

Journal Article · Thu Apr 01 04:00:00 EST 1976 · J. Bacteriol.; (United States)

OSTI ID:7282560

Koch, A L; Doyle, R J; Kubitschek, H E

Evidence is presented that near-ultraviolet (near-uv) light can alter galactoside transport in Escherichia coli in several independent ways. Earlier publications suggested that near-uv destroys cofactors needed for electron transport and thus places a limitation on energy reserves. In agreement, we found that the active accumulation of (/sup 14/C)thiomethyl-..beta..-D-galactopyranoside is decreased after irradiation by a larger factor than that due to action directly on the permease system. The effect on the latter was measured by the decrease in the rate of o-nitrophenyl-..beta..-D-galactopyranoside (ONPG) transport. As evidence that energy supplies for this ''downhill'' process did not become rate limiting after irradiation, we found that carbonylcyanide-m-chlorophenylhydrazone did not stimulate ONPG transport of irradiated cells. Cells genetically deficient in functional permease or cells treated with formaldehyde still transport ONPG passively, although at much lower rates. With the use of such cells, it was found that high fluences (doses) made the cells leaky. Further evidence that the permease system and the metabolic energy system can be inactivated independently is also presented. It is shown that a photoproduct from the irradiation of chloramphenicol inactivates the permease system much more efficiently than the energy system. In addition, it is shown that thio-..beta..-D-digalactopyranoside protects the permease system, but not the energy system, both against direct inactivation by near-uv and against photosensitized inactivation in the presence of chloramphenicol.

• Research Organization: Argonne National Lab., IL
• OSTI ID: 7282560
• Journal Information: J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 126:1; ISSN JOBAA
• Country of Publication: United States
• Language: English

Related Subjects

560131* -- Radiation Effects on Microorganisms-- Basic Studies-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANTIBIOTICS
BACTERIA
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CELL CONSTITUENTS
CELL MEMBRANES
CHLORAMPHENICOL
DRUGS
ELECTROMAGNETIC RADIATION
ENZYMES
ESCHERICHIA COLI
INACTIVATION
MEMBRANES
MICROORGANISMS
PERMEABILITY
RADIATION EFFECTS
RADIATIONS
ULTRAVIOLET RADIATION