Difference between revisions of "PMID:4577939"
(→Main Points of the Paper) |
(Table edited by Azweifel via TableEdit) |
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Line 77: | Line 77: | ||
''lacY<sup>UN</sup>'' | ''lacY<sup>UN</sup>'' | ||
| | | | ||
− | + | *Abolished lactose catabolic process | |
+ | *Absent growth on minimal salts medium with lactose | ||
+ | *Abolished utilization of carbon source (lactose) | ||
+ | |||
+ | |||
| | | | ||
Growth | Growth | ||
| | | | ||
− | in a minimal salts medium | + | inability to grow on lactose in a minimal salts medium |
| | | | ||
Other | Other | ||
Line 96: | Line 100: | ||
''lacY<sup>-</sup>'' | ''lacY<sup>-</sup>'' | ||
| | | | ||
− | + | *Decreased rate of alpha-galactosidase expression | |
+ | *Abolished induction of alpha-galactosidase expression | ||
+ | |||
| | | | ||
Metabolic Activity | Metabolic Activity | ||
Line 115: | Line 121: | ||
''lacY<sup>UN</sup>'' | ''lacY<sup>UN</sup>'' | ||
| | | | ||
− | White colonies on MacConkey melibiose indicator plates | + | *Abolished utilization of carbon source (melibiose) |
+ | *Abolished melibiose catabolic process | ||
+ | *White colonies on MacConkey melibiose indicator plates | ||
| | | | ||
Growth | Growth | ||
Line 135: | Line 143: | ||
''lacY<sup>UN</sup>'' | ''lacY<sup>UN</sup>'' | ||
| | | | ||
− | + | *Decreased intracellular accumulation of small molecule (IPTG) | |
+ | *Decreased activity of LacY transporter | ||
+ | *Increased facilitative diffusion of LacY? | ||
+ | *Decreased active transport of LacY? | ||
+ | *Energy-uncoupled transport? | ||
| | | | ||
Other | Other | ||
| | | | ||
− | mutant reached a maximum intracellular concentration of 0.1 mM compared to 0.4 mM IPTG for the energy-coupled parent | + | *mutant reached a maximum intracellular concentration of 0.1 mM compared to 0.4 mM IPTG for the energy-coupled parent |
+ | *reduced intracellular IPTG accumulation | ||
| | | | ||
Other | Other | ||
Line 154: | Line 167: | ||
''lacY<sup>UN</sup>'' | ''lacY<sup>UN</sup>'' | ||
| | | | ||
− | + | *Decreased induction of beta-galactosidase | |
+ | *Decreased rate of expression of beta-galactosidase | ||
+ | *Decreased lactose catabolic process | ||
+ | |||
| | | | ||
Metabolic Activity | Metabolic Activity | ||
| | | | ||
− | + | *reduced rate of beta-galactosidase induction | |
| | | | ||
Biochemical Assay | Biochemical Assay | ||
Line 174: | Line 190: | ||
''lacY<sup>UN</sup>'' | ''lacY<sup>UN</sup>'' | ||
| | | | ||
− | + | *Decreased utilization of carbon source (melibiose) | |
+ | *Decreased melibiose catabolic process | ||
+ | *Decreased growth rate on minimal salts medium with melibiose | ||
| | | | ||
Growth | Growth | ||
| | | | ||
− | in a minimal salts medium | + | *reduced growth rate on melibiose in a minimal salts medium |
| | | | ||
Plating Assay | Plating Assay | ||
Line 193: | Line 211: | ||
''lacY<sup>UN</sup>'' | ''lacY<sup>UN</sup>'' | ||
| | | | ||
− | + | *Decreased rate of alpha-galactosidase expression | |
+ | *Decreased induction of alpha-galactosidase | ||
| | | | ||
Metabolic Activity | Metabolic Activity | ||
| | | | ||
− | + | reduced rate of alpha-galactosidase induction | |
| | | | ||
Biochemical Assay | Biochemical Assay | ||
Line 212: | Line 231: | ||
''lacY<sup>UN</sup>'' | ''lacY<sup>UN</sup>'' | ||
| | | | ||
− | + | *Decreased affinity for lactose binding | |
+ | *Decreased substrate binding | ||
+ | *Decreased transport of small molecules | ||
| | | | ||
Other | Other | ||
| | | | ||
− | + | decreased affinity for lactose | |
| | | | ||
Other | Other | ||
Line 231: | Line 252: | ||
''lacY<sup>UN</sup>'' | ''lacY<sup>UN</sup>'' | ||
| | | | ||
− | Light pink colonies on MacConkey lactose indicator plates | + | *Decreased utilization of carbon source (lactose) |
+ | *Decreased lactose catabolic process | ||
+ | *Light pink colonies on MacConkey lactose indicator plates | ||
| | | | ||
Growth | Growth | ||
Line 271: | Line 294: | ||
''lacY<sup>UN</sup>'' | ''lacY<sup>UN</sup>'' | ||
| | | | ||
− | Light pink colonies on MacConkey melibiose indicator | + | *Decreased utilization of carbon source (melibiose) |
+ | *Decreased melibiose catabolic activity | ||
+ | *Light pink colonies on MacConkey melibiose indicator plate | ||
| | | | ||
Growth | Growth | ||
Line 291: | Line 316: | ||
''lacY<sup>UN</sup>'' | ''lacY<sup>UN</sup>'' | ||
| | | | ||
− | + | *Abolished lactose catabolic process | |
+ | *Absent growth on minimal salts medium with lactose | ||
+ | *Abolished utilization of carbon source (lactose) | ||
+ | |||
+ | |||
| | | | ||
Growth | Growth | ||
| | | | ||
− | in liquid culture with lactose concentrations b/t 5M and 50mM | + | no growth on lactose in liquid culture with lactose concentrations b/t 5M and 50mM |
| | | | ||
Line 311: | Line 340: | ||
''lacY<sup>UN</sup>'' | ''lacY<sup>UN</sup>'' | ||
| | | | ||
− | + | *Increased affinity for melibiose | |
+ | *Increased small molecule transport | ||
+ | *Increased melibiose binding | ||
| | | | ||
Other | Other |
Revision as of 16:35, 26 January 2011
Citation |
Kusch, M and Wilson, TH (1973) Defective lactose utilization by a mutant of Escherichia coli energy-uncoupled for lactose transport. The advantages of active transport versus facilitated diffusion.Biochim. Biophys. Acta 311:109-22 |
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Abstract |
No abstract in PubMed |
Links | |
Keywords |
Biological Transport; Biological Transport, Active; Carbon Isotopes; Cell Division; Densitometry; Diffusion; Disaccharides; Enzyme Induction; Escherichia coli; Galactosidases; Kinetics; Lactose; Mutation; Transduction, Genetic |
edit table |
Main Points of the Paper
- Mutants described in this paper were defective in energy-dependent accumulation of thiogalactosides, but showed no loss of carrier-mediated transport
- Inducible energy-uncoupled mutant (54-41) was unable to grow on lactose minimal medium. Inducer IPTG permitted normal growth in these cells
- In the energy-uncoupled mutant, the rate of induction of β-galactosidase by lactose and by low concentrations of IPTG was mucher slower than the parent
- X71-54 (constitutive mutant) grew poorly on melibiose, due to the inability of this sugar to induce α-galactosidase
- For normal growth of inducible cells on lactose and melibiose, carrier-mediated entry (facilitated diffusion) of substrates is inadequate; the membrane carriers must also be capable of accumulating the sugars
Materials and Methods Used
- Parent Strain: X71 (i-z+y+a-, proC-, try-, B1-)
- Additional Strain: X71-54 (i-z+yUNa-)- energy uncoupled mutant
- Additional Strain: X71-15 (i+z+y+a-)
- Additional Strain: X9003 (i+z-y+a+, B1-)
- Additional Strain: 54-41 (i+z+yUNa-)
- Additional Strain: 316 (i-z+y-a-)- y- strain
- β-galactosidase assay
- α-galactosidase assay
- Carrier-mediated transport assay
- thiogalactoside transacetylase activity was determined
- P1 Transduction
Phenotype Annotations
<protect>
Species | Taxon ID | Strain | Gene (if known) | OMP | Phenotype | Details | Evidence | Notes |
---|---|---|---|---|---|---|---|---|
Escherichia coli |
NCBI:562 |
X71-54 |
lacYUN |
|
Growth |
inability to grow on lactose in a minimal salts medium |
Other |
in text, pg. 113 |
Escherichia coli |
NCBI:562 |
316 |
lacY- |
|
Metabolic Activity |
alpha-gal activity |
Biochemical Assay |
in text- pg. 116 |
Escherichia coli |
NCBI:562 |
54-41 |
lacYUN |
|
Growth |
inability to ferment 0.2% melibiose |
Plating Assay |
Table 4 |
Escherichia coli |
NCBI:562 |
54-41 |
lacYUN |
|
Other |
|
Other |
Figure 1- [14C]IPTG uptake |
Escherichia coli |
NCBI:562 |
54-41 |
lacYUN |
|
Metabolic Activity |
|
Biochemical Assay |
Figure 4- beta-galactosidase activity measured after lactose induction |
Escherichia coli |
NCBI:562 |
X71-54 |
lacYUN |
|
Growth |
|
Plating Assay |
Table 3 |
Escherichia coli |
NCBI:562 |
X71-54 |
lacYUN |
|
Metabolic Activity |
reduced rate of alpha-galactosidase induction |
Biochemical Assay |
Figure 5- alpha-galactosidase activity measured after melibiose induction |
Escherichia coli |
NCBI:562 |
54-41 |
lacYUN |
|
Other |
decreased affinity for lactose |
Other |
Table 5- kinetics of transporter for potential inducer molecules |
Escherichia coli |
NCBI:562 |
54-41 |
lacYUN |
|
Growth |
reduced ability to ferment 0.2% lactose (fully restored when IPTG is present) |
Plating Assay |
Table 4 |
Escherichia coli |
NCBI:562 |
X71-54 |
lacYUN |
Light pink colonies on MacConkey melibiose indicator plates |
Growth |
inability to ferment 0.2% melibiose |
Plating Assay |
Table 4 |
Escherichia coli |
NCBI:562 |
X71-54 |
lacYUN |
|
Growth |
reduced ability to ferment 0.2% melibiose |
Plating Assay |
Table 4 |
Escherichia coli |
NCBI:562 |
54-41 |
lacYUN |
|
Growth |
no growth on lactose in liquid culture with lactose concentrations b/t 5M and 50mM |
Plating Assay |
in text, pg. 117- addition of 0.5mM IPTG added to lactose medium lead to growth comparable to parent with no constitutive cells |
Escherichia coli |
NCBI:562 |
54-41 |
lacYUN |
|
Other |
Other |
Table 5- kinetics of transporter for potential inducer molecules | |
edit table |
</protect>