Effect of catabolite repression on the mer operon

Journal Article · Fri Jan 01 04:00:00 EST 1982 · J. Bacteriol.; (United States)

OSTI ID:5638075

Summers, A O; Kight-Olliff, L; Slater, C

The plasmid-determined mer operon, which provides resistance to inorganic mercury compounds, was subject to a 2.5-fold decrease in expression when glucose was administered at the same time as the inducer HgCl/sub 2/. This glucose-mediated transient repression of the operon was overcome by the addition of cyclic AMP. Permanent catabolite repression of the operon was observed in the 1.6- to 1.9-fold decrease in expression in mutants lacking either adenyl cyclase (cya) or the catabolite activator protein (crp). The effect of the cya mutation on mer expression could be overcome by the addition of cyclic AMP at the time of induction. In addition to these effects on the whole cells of wild-type strains, we examined the effect of catabolite repression on the expression of the mercuric ion (Hg(II)) reductase enzyme, assayable in cell extracts, and on the Hg(II) uptake system, assayable in a mutant strain which lacked reductase activity. There was a two- to threefold effect of repression on the Hg(II) reductase enzyme assayable in vitro after induction under catabolite repressing conditions (either with glucose or in the crp and cya mutants). We did not find a similar repressing effect on the induction of the Hg(II) uptake system, which is also determined by the mer operon.

• Research Organization: University of Georgia, Athens
• OSTI ID: 5638075
• Journal Information: J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 149:1; ISSN JOBAA
• Country of Publication: United States
• Language: English

Related Subjects

550700* -- Microbiology
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
AMP
BACTERIA
BIOASSAY
CARBOHYDRATES
CATABOLISM
CELL CONSTITUENTS
CHLORIDES
CHLORINE COMPOUNDS
ENZYME ACTIVITY
ENZYMES
GENES
GLUCOSE
HALIDES
HALOGEN COMPOUNDS
HEXOSES
INHIBITION
MERCURY CHLORIDES
MERCURY COMPOUNDS
MERCURY HALIDES
METABOLISM
MICROORGANISMS
MONOSACCHARIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
OXIDOREDUCTASES
PLASMIDS
RESPONSE MODIFYING FACTORS
SACCHARIDES