SOME OBSERVATIONS CONCERNING DNA AND β-GALACTOSIDASE SYNTHESIS IN ESCHERICHIA COLI B

1967 ◽  
Vol 13 (4) ◽  
pp. 377-388 ◽  
Author(s):  
S. J. Webb ◽  
J. Singh Bhorjee ◽  
Janet L. Walker ◽  
D. A. Rokosh
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Enzyme Synthesis ◽  
Induction Medium ◽  
Minute Period ◽  
Rate Characteristic ◽  
Two Stages ◽  
Escherichia Coli B

When starved cells of thymine-requiring Escherichia coli B were placed in a complete induction medium there was an initial lag of 10 minutes before measurable amounts of the enzyme were detected. Cells exposed for 15 minutes to one inducer and then given an alternative inducer continued to manufacture the enzyme for 60 minutes at a rate characteristic of the initial inducer. After this period, enzyme manufacture assumed the characteristics of the second inducer. Glucose or mitomycin was found to inhibit enzyme synthesis only when they were added during the first 10 minutes or 45- to 60-minute periods of induction. Chloramphenicol stopped enzyme synthesis at any stage of induction. The synthesis of DNA was found to occur in two stages and enzyme synthesis was prevented by glucose or mitomycin only if they were added to the cells during a 10-minute period which immediately preceded DNA replication. It is concluded that a gene can express itself only once, and change in expression requires the synthesis of new DNA.

THE INFLUENCE OF TIME AND MEDIA CHANGES ON THE INDUCTION AND SUPPRESSION OF β-GALACTOSIDASE SYNTHESIS IN ESCHERICHIA COLI B

1967 ◽  
Vol 13 (3) ◽  
pp. 257-269
Author(s):  
S. J. Webb ◽  
Janet L. Walker
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Minimal Medium ◽  
Sole Source ◽  
Enzyme Synthesis ◽  
Induction Medium ◽  
Nucleic Acid Bases ◽  
Apparent Effect ◽  
Lag Period ◽  
Escherichia Coli B

When cells of Escherichia coli B were grown in a glucose – amino acid medium and then transferred to a minimal medium containing lactose or isopropyl-β-D-thiogalactopyranoside as a sole source of carbon, no induction of β-galactosidase occurred unless one or several amino acids were supplied. Of the amino acids tested, aspartic acid was the most effective and its ability to initiate the synthesis of the enzyme was increased by the addition of arginine. In the presence of these two, or all of the amino acids, there was a lag period of 10 min before enzyme synthesis occurred. The duration of the lag period was unaffected by the addition of nucleic acid bases or succinate to the induction medium. Succinate or glutamate partially inhibited the synthesis of the enzyme, whereas glucose, inositol, or chloramphenicol completely suppressed it. With the exception of that produced by chloramphenicol, inhibition was dependent on the time at which the inhibitor was added. If inhibitors were added after the 10-min lag period, they had no apparent effect until 45 min had elapsed. Cells transferred after 15 min from one induction medium to another displayed for 30 min the induction characteristics of the first medium. It appears that a process occurring during the early 15-min period determines the rate at which enzymes will be synthesized for the next 30 min and that the action of inhibitors is to prevent this process. The process seems to require intact DNA and amino acids and it is suggested that it determines the specificity and quantity of mRNA manufactured.

scholarly journals Evidence that dimers remaining in preinduced Escherichia coli B/r Hcr+ become insensitive after DNA replication to the extract from Micrococcus luteus

1981 ◽  
Vol 36 (2) ◽  
pp. 429-441 ◽  
Author(s):  
M. Sedliaková ◽  
J. Brozmanová ◽  
F. Masek ◽  
K. Kleibl
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Micrococcus Luteus ◽  
Escherichia Coli B

THE EFFECT OF 3000–4000 Å LIGHT ON THE SYNTHESIS OF β-GALACTOSIDASE AND BACTERIOPHAGES BY ESCHERICHIA COLI B

1967 ◽  
Vol 13 (1) ◽  
pp. 69-79 ◽  
Author(s):  
S. J. Webb ◽  
J. Singh Bhorjee
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Dna Replication ◽  
Glutamic Acid ◽  
Strong Correlation ◽  
Sublethal Doses ◽  
Time Periods ◽  
Escherichia Coli B

The irradiation of Escherichia coli B with sublethal doses of 3000–4000 Å light prevented the microorganisms from manufacturing β-galactosidase and T2 and T7 coliphages. Inhibition occurred only if the cells were irradiated immediately after their contact with the inducer lactose or infection with T2 and T7 phages. If, before irradiation the cells were allowed to incubate for 15 min after the addition of lactose or the coliphages to the cells, little effect of the light was found. The uptake of uracil and amino acids by washed cells was more rapid in the first 15 min than during later time periods while thymine uptake did not begin until the first 15 min had elapsed. The 3000–4000 Å light inhibited the uptake of arginine and thymine but not uracil or glutamic acid. The addition of 5% inositol inhibited the synthesis of β-galactosidase and the uptake of14C-labelled metabolites. Since there was a strong correlation between the degree to which arginine and thymine uptakes were inhibited by the light or inositol, it appears that the production of a protein during the first 15 min is intimately connected with DNA replication and the synthesis of induced enzymes.

scholarly journals The mechanism of sensitivity to phleomycin in growing Escherichia coli cells

1976 ◽  
Vol 155 (1) ◽  
pp. 87-99 ◽  
Author(s):  
M J Sleigh ◽  
G W Grigg
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Cell Membrane ◽  
Dna Breakage ◽  
Escherichia Coli Cells ◽  
Low Concentrations ◽  
Cellular Change ◽  
Initiation Of Dna Replication ◽  
Cellular Dna ◽  
Escherichia Coli B

Stationary-phase Escherichia coli B cells transferred to new growth medium are initially resistant to net DNA breakage by low concentrations of phleomycin, and become sensitive as DNA replication commences. From studies with inhibitors of various stages of the DNA replication cycle it is evident that it is not DNA synthesis itself that is required for induction of DNA breakage by phleomycin, but events associated with the initiation of DNA replication. Termination of replication in the absence of further initiaiton results in resistance to phleomycin. The cellular change responsible for changes in sensitivity to phleomycin could be the attachment of the bacterial chromosome to the cell membrane at initiation and detachment on termination of replication, suggesting an alteration in the balance between cellular DNA breakage and repair processes for membrane-associated compared with non-membrane-associated DNA.

scholarly journals ENZYME BIOSYNTHESIS IN ESCHERICHIA COLI

1959 ◽  
Vol 42 (6) ◽  
pp. 1207-1218 ◽  
Author(s):  
George Weinbaum ◽  
M. F. Mallette
Keyword(s):  
Escherichia Coli ◽  
Enzyme System ◽  
Enzyme Synthesis ◽  
Limiting Factor ◽  
Enzyme Systems ◽  
Radioactive Sample ◽  
Free Media ◽  
Favorable Conditions ◽  
Escherichia Coli B ◽  
Exogenous Nitrogen

Escherichia coli B synthesized ß-galactosidase and an enzyme system for D-xylose when exposed to lactose and xylose respectively in nitrogen-free media. The amount of ß-galactosidase formed in the absence of external nitrogen depended upon the nature of the medium in which the cells had originally been grown. Half as much of this enzyme was synthesized without exogenous nitrogen by cells taken from a nitrogen-rich medium as was formed by cells under favorable conditions with an external supply of nitrogen. Escherichia coli B contained a pool of nitrogen compounds soluble in 80 per cent ethanol and made up of several ninhydrin-positive components. One of these was identified chromatographically as glycine using an authentic radioactive sample. Another substance behaved like serine on the chromatograms. The internal pool of amino acids and peptides was large enough to account for the ß-galactosidase synthesized by cells exposed to lactose in a medium free of nitrogen. Some degree of interaction of the syntheses of the ß-galactosidase and xylose enzyme systems was observed in nitrogen-free media. This interaction produced a greater effect on the formation of ß-galactosidase and was attributed to a limiting factor(s) in the internal nitrogenous pool or to a limiting intermediate in enzyme synthesis.

UV-inducible repair: Influence on survival, dimer excision, DNA replication and breakdown in Escherichia coli B/r Hcr+ cells

1978 ◽  
Vol 160 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Milena Sedliaková ◽  
Viera Slezáriková ◽  
František Mašek ◽  
Jela Brozmanová
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Escherichia Coli B ◽  
Inducible Repair

L-Asparaginase production during static incubation of aerobically grown Escherichia coli B

1973 ◽  
Vol 19 (10) ◽  
pp. 1251-1257 ◽  
Author(s):  
L. D. Boeck ◽  
P. P. K. Ho
Keyword(s):  
Escherichia Coli ◽  
Cell Proliferation ◽  
Amino Acid ◽  
B Cells ◽  
Amino Acid Analysis ◽  
Enzyme Synthesis ◽  
E Coli ◽  
Low Levels ◽  
Escherichia Coli B ◽  
Aerobic Cell

Glucose, galactose, or pyruvate independently supported biosynthesis of 1.5–2.6 IU/ml of antilymphoma L-asparaginase during static incubation of aerobically grown E. coli B cells. Fructose, lactate, and other compounds did not produce enzyme levels in excess of 0.12 IU/ml. Asparaginase synthesis by cells incubated in the presence of either glucose or pyruvate was inhibited by fluoride, iodoacetate, and sulfite. Amino acid analysis of the modified trypticase soy broth (MTSB) medium, used for aerobic cell proliferation and subsequent enzyme synthesis during static incubation, permitted development of a chemically defined (CD) medium. Washed cells, grown aerobically in the MTSB medium, produced equivalent quantities of L-asparaginase in both the MTSB and CD media. Low levels of chloramphenicol or puromycin reduced enzyme synthesis by as much as 95%.

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