PMID:14430363: Difference between revisions
Table edited by Azweifel via TableEdit |
Table edited by Azweifel via TableEdit |
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constitutive expression of beta-galactosidase | constitutive expression of beta-galactosidase | ||
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Expression | |||
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lac genes were transferred from Hfr (z+i+) into F- (z-i-) during conjugation and LacZ production became constitutive within the first few minutes after transfer | lac genes were transferred from Hfr (z+i+) into F- (z-i-) during conjugation and LacZ production became constitutive within the first few minutes after transfer | ||
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inducible expression of beta-galactosidase | inducible expression of beta-galactosidase | ||
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Expression | |||
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lac genes were transferred from Hfr (z+i+) into F- (z-i-) during conjugation and LacZ production became inducible about an hour after transfer | lac genes were transferred from Hfr (z+i+) into F- (z-i-) during conjugation and LacZ production became inducible about an hour after transfer | ||
Revision as of 22:26, 16 December 2010
| Citation |
PARDEE, AB and PRESTIDGE, LS (1959) On the nature of the repressor of beta-galactosidase synthesis in Escherichia coli.Biochim. Biophys. Acta 36:545-7 |
|---|---|
| Abstract |
No abstract in PubMed |
| Links | |
| Keywords |
Escherichia coli; Glycoside Hydrolases |
| edit table |
Main Points of the Paper
- Hfr(z+i+) X F-(z-i-):
- within a few minutes of the time of entry of the z+i+ genes (which are closely linked) the synthesis of β-galactosidase commenced at maximal velocity in the absence of extracellular inducer
- inducible i+ allele appears dominant over the constitutive i- allele
- The idea that i+ could control the synthesis of a destructive enzyme which removes an endogenous intracellular inducer was eliminated due to observations from this paper (Figure 1, Curves C & D).
- The presence of 5-methyltryptophan enhances mating efficiency
- The data in this paper may suggest that:
- an inducer-destroying enzyme is not responsible for the difference between inducibility and constitutivity
- the repressor is not a protein, although the authors state this conclusion is open to doubt (evidence to refute this conclusion is shown here).
Materials and Methods Used
- Strains:
- Hfr (z+i+)
- F- (z-i-)
- Conjugation
- Reagents
- Streptomycin
- Chloramphenicol
- 5-methytryptophan
- Duponol C(Na lauryl sulfate)
Phenotype Annotations
| Species | Taxon ID | Strain | Gene (if known) | OMP | Phenotype | Details | Evidence | Notes |
|---|---|---|---|---|---|---|---|---|
|
Escherichia coli |
NCBI:562 |
lacZ- lacI- |
constitutive expression of beta-galactosidase |
Expression |
lac genes were transferred from Hfr (z+i+) into F- (z-i-) during conjugation and LacZ production became constitutive within the first few minutes after transfer |
Biochemical Assay |
Figure 1- curves A and B (LacZ assay) | |
|
Escherichia coli |
NCBI:562 |
lacZ- lacI- |
inducible expression of beta-galactosidase |
Expression |
lac genes were transferred from Hfr (z+i+) into F- (z-i-) during conjugation and LacZ production became inducible about an hour after transfer |
Biochemical Assay |
Figure 1- curve A vs. curve B (LacZ assay) | |
| edit table |
