Relationship between ppGpp levels and rates of protein and RNA synthesis in Escherichia coli

1976 ◽  
Vol 54 (3) ◽  
pp. 291-295 ◽  
Author(s):  
Gillian Chaloner-Larsson ◽  
Hiroshi Yamazaki
Keyword(s):  
Escherichia Coli ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Inverse Relationship ◽  
Rna Synthesis ◽  
Amino Acid Starvation ◽  
Cellular Proteins ◽  
Mrna Species ◽  
Protein And Rna Synthesis ◽  
Rna And Protein Synthesis

When amino acid starvation is ended in stringent (relA+) strains of Escherichia coli, the rates of RNA and protein synthesis as well as their accumulation return to normal more slowly in spoT− strains than in the spoT+ strains. The level of ppGpp accumulated declines more slowly in the spoT− strains than in the spoT+ strains. Thus, there is an inverse relationship between ppGpp levels and the rates of RNA and protein synthesis. The slow resumption of protein synthesis in the spoT−relA+ strains could therefore be explained in terms of the limited synthesis of mRNA species coding for the bulk of cellular proteins.

scholarly journals Multi-step resistance to Chloramphenicol in RC-stringent Escherichia coli K12—its effect on the induction of RNA synthesis by antibiotics under amino acid starvation

1965 ◽  
Vol 6 (2) ◽  
pp. 304-309 ◽  
Author(s):  
E. C. R. Reeve ◽  
J. O. Bishop
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Resistant Strain ◽  
Parent Strain ◽  
Rna Synthesis ◽  
Amino Acid Starvation ◽  
Sensitive Strain ◽  
Escherichia Coli K12 ◽  
High Doses

A multi-step Chloramphenicol (CM)-resistant derivative of an RC-stringent strain of Escherichia coli auxotrophic for threonine and leucine was resistant also to Aureomycin (AM) and Puromycin (PM). All three antibiotics released the repression of RNA synthesis due to amino acid starvation in the CM-sensitive parent strain, their relative activities being about 1:10:100 for AM: CM: PM. High doses of AM and CM failed to induce RNA synthesis. The CM-resistant strain required greater concentrations of each antibiotic than the sensitive strain to induce the same level of RNA synthesis, and appeared to be about one hundred times, ten times and five times more resistant to CM, AM and PM, respectively, than the sensitive strain.

scholarly journals The control of haemoglobin synthesis: factors controlling the output of α and β chains

1969 ◽  
Vol 28 (02) ◽  
pp. 248-254 ◽  
Author(s):  
R. T. Hunt ◽  
A. R. Hunter ◽  
A. J. Munro
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Rna Synthesis ◽  
Amino Acid Starvation ◽  
Control Mechanisms ◽  
Actual Process ◽  
Haemoglobin Synthesis

Analysis of the effects of amino acid starvation in reticulocytes is comparatively simple compared with similar analysis in other tissues of whole organisms. This is mainly because of the absence of RNA synthesis in reticulocytes, but also because the bulk of the protein being synthesized is haemoglobin, a protein whose structure is completely known. The absence of RNA synthesis eliminates complications that would otherwise arise through RNA-mediated control mechanisms which in turn might mask the effects of amino acid starvation on the protein synthetic machinery in the cells (Munro, 1969). Consequently reticulocytes have been used to study the effect of amino acid starvation on the actual process of protein synthesis and assembly.

scholarly journals The control of haemoglobin synthesis: factors controlling the output of α and β chains

1969 ◽  
Vol 28 (2) ◽  
pp. 248-254 ◽  
Author(s):  
R. T. Hunt ◽  
A. R. Hunter ◽  
A. J. Munro
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Rna Synthesis ◽  
Amino Acid Starvation ◽  
Control Mechanisms ◽  
Actual Process ◽  
Haemoglobin Synthesis

Analysis of the effects of amino acid starvation in reticulocytes is comparatively simple compared with similar analysis in other tissues of whole organisms. This is mainly because of the absence of RNA synthesis in reticulocytes, but also because the bulk of the protein being synthesized is haemoglobin, a protein whose structure is completely known. The absence of RNA synthesis eliminates complications that would otherwise arise through RNA-mediated control mechanisms which in turn might mask the effects of amino acid starvation on the protein synthetic machinery in the cells (Munro, 1969). Consequently reticulocytes have been used to study the effect of amino acid starvation on the actual process of protein synthesis and assembly.

scholarly journals Synthesis of ribonucleic acid in purine-deficient Escherichia coli and a comparison with the effects of amino acid starvation

1970 ◽  
Vol 120 (1) ◽  
pp. 125-132 ◽  
Author(s):  
N. F. Varney ◽  
Gillian A. Thomas ◽  
K. Burton
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Rna Polymerase ◽  
Ribonucleic Acid ◽  
Rna Synthesis ◽  
Adenine Nucleotides ◽  
Amino Acid Starvation ◽  
Guanine Nucleotides ◽  
Purine Nucleotides ◽  
Acid Control

1. Experiments with rifampicin and stringent strains of Escherichia coli (pro−purB−rel+) indicate that purine deficiency does not decrease and may considerably increase the potential for RNA synthesis by RNA polymerase molecules that are bound to DNA and have already commenced transcription. 2. DNA–RNA hybridization experiments indicate that purine starvation increases the distribution of bound RNA polymerase molecules between the cistrons for mRNA and those for stable RNA. 3. Synthesis of β-galactosidase mRNA is more dependent on the ability to synthesize guanine nucleotides than on the ability to synthesize adenine nucleotides. 4. Amino acid starvation tends to decrease the potential for RNA synthesis by RNA polymerase molecules bound to DNA. 5. Since this effect differs from that due to purine starvation, amino acid control of RNA synthesis does not appear to operate solely by causing a deficiency of purine nucleotides. 6. The results are discussed in terms of the ability to initiate RNA chains and to extend them under different circumstances.

RNA synthesis in T4 infected Escherichia coli during amino acid starvation

Virology ◽  
1972 ◽  
Vol 50 (1) ◽  
pp. 273-276 ◽  
Author(s):  
Pierluigi Donini ◽  
Gordon Edlin
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Rna Synthesis ◽  
Amino Acid Starvation

Inhibition of protein synthesis by zinc: comparison between protein synthesis and RNA synthesis

1998 ◽  
Vol 17 (12) ◽  
pp. 661-667 ◽  
Author(s):  
Udo Ingbert Walther ◽  
Johannes Schulze ◽  
Wolfgang Forth
Keyword(s):  
Protein Synthesis ◽  
Rna Synthesis ◽  
A549 Cells ◽  
Zinc Toxicity ◽  
Alveolar Type ◽  
Time Curve ◽  
Synthesis Inhibition ◽  
Protein And Rna Synthesis ◽  
Rna And Protein Synthesis

Inhalation of zinc fumes may lead to the acute respiratory distress syndrome. The mechanisms of pulmonary zinc toxicity are not yet understood. Therefore we investigated zinc-dependent depression of protein and RNA synthesis in rat and human lung cell lines. 1 After exposure to 120 or 150 mmol/l zinc, RNA synthesis as assessed by uridine incorporation decreased by 60-70% between 0 and 2 h exposition in rat alveolar type II cells (L2 cells) and human fibroblast-like cells (11Lu and 16Lu cells), and by 90% between 0 and 4 h in carcinoma-derived cells (A549 cells). 2 After 2 h exposure, L2, 11Lu, and 16Lu cells were half-maximally inhibited by 50 mmol/l zinc, whereas A549 cells were more resistant with half-maximal inhibition at 100 mmol/zinc. 3 Protein and RNA synthesis was inhibited in parallel in L2, 11Lu, and A549 cells as indicated by simultaneous determination of uridine and amino acid incorporation. In 16Lu cells, the decline in protein synthesis preceded RNA synthesis inhibition. Pretreatment with RNA synthesis inhibitors (amanitin or actinomycin D) had no effect on time curve and intensity of RNA synthesis inhibition. Taken together, our results indicate that the suppression of RNA and protein synthesis likely are independent phenomena, due to direct zinc effects on these biosynthetic pathways.

THE EFFECT OF ACTINOBOLIN ON NUCLEIC ACID AND PROTEIN SYNTHESIS IN ESCHERICHIA COLI

1966 ◽  
Vol 12 (3) ◽  
pp. 515-520 ◽  
Author(s):  
D. E. Hunt ◽  
R. F. Pittillo ◽  
E. P. Johnson ◽  
F. C. Moncrief
Keyword(s):  
Escherichia Coli ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Nucleic Acid ◽  
Mechanism Of Action ◽  
Rna Synthesis ◽  
The Other ◽  
Cross Resistance ◽  
Inhibition Of Protein Synthesis

Actinobolin inhibits protein synthesis in Escherichia coli. When the antibiotic is added to a culture at the time of inoculation, RNA synthesis is also inhibited. Inhibition of RNA synthesis appears to be a consequence of inhibition of protein synthesis. Cross-resistance experiments suggest that the mechanism of action of actinobolin differs from that of the other inhibitors of protein synthesis, chloramphenicol and sparsomycin. Phenylalanine prevents the action of actinobolin provided the amino acid and antibiotic are added simultaneously; this effect is not observed if the phenylalanine is added 1 hour after the addition of the antibiotic. Evidence is presented that the mechanism by which phenylalanine prevents inhibition by actinobolin differs from that which has been suggested for azaserine and p-fluorophenylalanine.

Effects of the spoT and relA Mutation on the Synthesis and Accumulation of ppGpp and RNA during Glucose Starvation

1978 ◽  
Vol 56 (4) ◽  
pp. 264-272 ◽  
Author(s):  
Gillian Chaloner-Larsson ◽  
Hiroshi Yamazaki
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Rna Synthesis ◽  
Amino Acid Starvation ◽  
Protein Accumulation ◽  
Glucose Starvation ◽  
Basal Rate ◽  
Synthetic Rate ◽  
K 12 ◽  
Stimulation Of

The effects of glucose starvation on the accumulation and synthesis of guanosine 3′,5′-bis(diphosphate) (ppGpp) were compared in four Escherichia coli K-12 strains having four different combinations of the spoT and relA alleles: spoT+relA+, spoT relA+, spoT+relA, and spoT relA. Glucose starvation caused a rapid and complete inhibition of RNA and protein accumulation and severe inhibition of RNA synthesis in all four strains. However, ppGpp accumulated only gradually in the relaxed (relA) strains and rapidly in the stringent (relA+) strains. Thus, ppGpp accumulation is not obligatory to the inhibition of RNA synthesis and accumulation during glucose starvation. During growth, relA strains synthesized ppGpp at a rate comparable with that in their relA+ partners. Glucose starvation did not affect the basal rate of ppGpp synthesis in the relA strains, but caused a transient stimulation of ppGpp synthesis in the relA+ strains. This suggests that glucose starvation causes transient amino-acid starvation. Since ppGpp accumulated in the relA strain without a change in its synthetic rate, it is inferred that ppGpp degradation decreased during glucose starvation. During growth, the turnover of ppGpp was considerably slower in the spoT strains than in the spoT+ strains. This suggests that the slower degradation of ppGpp in the spoT strains is counterbalanced by the slower synthesis of ppGpp. This difference in the rate of ppGpp synthesis became apparent when the relA strains were starved for glucose: The spoT relA strain accumulated ppGpp more slowly than did the spoT+relA strain.

FEMALE ENDOCRINE CONTROL MECHANISMS DURING THE NEONATAL PERIOD

1972 ◽  
Vol 70 (2) ◽  
pp. 396-408 ◽  
Author(s):  
K.-D. Schulz ◽  
H. Haarmann ◽  
A. Harland
Keyword(s):  
Protein Synthesis ◽  
Reproductive System ◽  
Rna Synthesis ◽  
Neonatal Period ◽  
High Dose ◽  
Female Reproductive System ◽  
Endocrine Control ◽  
Hypothalamic Region ◽  
Rna And Protein Synthesis ◽  
Physiological Dose

ABSTRACT The present investigation deals with the oestrogen-sensitivity of the female reproductive system during the neonatal period. Newborn female guinea pigs were used as test animals. At different times after a single subcutaneous injection of a physiological dose of 0.1 μg or an unphysiologically high dose of 10 μg 17β-oestradiol/100 g body weight, the RNA- and protein-synthesis was examined in the hypothalamic region, pituitary, cerebral cortex, liver, adrenal gland, ovary and uterus. With a physiological dose an increase in organ weight, protein content, RNA-and protein-synthesis was found only in the uterus. These alterations turned out to be dose-dependent. In addition to the findings in the uterus an inhibition of the aminoacid incorporation rate occurred in the liver following the injection of the high oestradiol dose. As early as 1 hour after the administration of 0.1 μg 17β-oestradiol an almost 100% increase in uterine protein synthesis was detectable. This result demonstrates a high oestrogen-sensitivity of this organ during the neonatal period. All the other organs of the female reproductive system such as the hypothalamus, pituitary and ovary did not show any oestrogen response. Therefore the functional immaturity of the uterus during post partem life is not the result of a deficient hormone sensitivity but is correlated with the absence of a sufficient hormonal stimulus at this time. The investigation on the effects of actinomycin resulted in different reactions in the uterus and liver. In contrast to the liver a paradoxical actinomycin effect was found in the uterus after treatment with actinomycin alone. This effect is characterized by a small inhibition of RNA-synthesis and a 50% increase in protein synthesis. The treatment of the newborn test animals with actinomycin and 17β-oestradiol together abolished the oestrogen-induced stimulation of the uterine RNA-and protein-synthesis. Consequently, the effect of oestrogens during the neonatal period is also connected with the formation of new proteins via an increased DNA-directed RNA-synthesis.

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