Changes in cell dimensions during amino acid starvation of Escherichia coli

1982 ◽  
Vol 152 (1) ◽  
pp. 35-41
Author(s):  
N Grossman ◽  
E Z Ron ◽  
C L Woldringh
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Amino Acid ◽  
Microscopic Analysis ◽  
Amino Acid Starvation ◽  
Cell Diameter ◽  
Electron Microscopic ◽  
Generation Times ◽  
Cell Dimensions ◽  
K 12

Electron microscopic analysis was used to study cells of Escherichia coli B and K-12 during and after amino acid starvation. The results confirmed our previous conclusion that cell division and initiation of DNA replication occur at a smaller cell volume after amino acid starvation. Although during short starvation periods, the number of constricting cells decreased due to residual division, it appears that during prolonged starvation, cells of E. coli B and K-12 were capable of initiating new constrictions. During amino acid starvation, cell diameter decreased significantly. The decrease was reversed only after two generation times after the resumption of protein synthesis and was larger in magnitude than that previously observed before division (F. J. Trueba and C. L. Woldringh, J. Bacteriol. 142:869-878, 1980). This decrease in cell diameter correlates with synchronization of cell division which has been shown to occur after amino acid starvation.

scholarly journals Control of cell division in Escherichia coli: effect of amino acid starvation.

1977 ◽  
Vol 129 (2) ◽  
pp. 569-573 ◽  
Author(s):  
E Ron ◽  
N Grossman ◽  
C E Helmstetter
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Amino Acid ◽  
Amino Acid Starvation

scholarly journals Deficiency in l-Serine Deaminase Interferes with One-Carbon Metabolism and Cell Wall Synthesis in Escherichia coli K-12

2010 ◽  
Vol 192 (20) ◽  
pp. 5515-5525 ◽  
Author(s):  
Xiao Zhang ◽  
Ziad W. El-Hajj ◽  
Elaine Newman
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Cell Division ◽  
Amino Acid ◽  
Cell Wall Synthesis ◽  
E Coli ◽  
Amino Acid Mixtures ◽  
Glycine Cleavage ◽  
High Level ◽  
K 12

ABSTRACT Escherichia coli K-12 provided with glucose and a mixture of amino acids depletes l-serine more quickly than any other amino acid even in the presence of ammonium sulfate. A mutant without three 4Fe4S l-serine deaminases (SdaA, SdaB, and TdcG) of E. coli K-12 is unable to do this. The high level of l-serine that accumulates when such a mutant is exposed to amino acid mixtures starves the cells for C1 units and interferes with cell wall synthesis. We suggest that at high concentrations, l-serine decreases synthesis of UDP-N-acetylmuramate-l-alanine by the murC-encoded ligase, weakening the cell wall and producing misshapen cells and lysis. The inhibition by high l-serine is overcome in several ways: by a large concentration of l-alanine, by overproducing MurC together with a low concentration of l-alanine, and by overproducing FtsW, thus promoting septal assembly and also by overexpression of the glycine cleavage operon. S-Adenosylmethionine reduces lysis and allows an extensive increase in biomass without improving cell division. This suggests that E. coli has a metabolic trigger for cell division. Without that reaction, if no other inhibition occurs, other metabolic functions can continue and cells can elongate and replicate their DNA, reaching at least 180 times their usual length, but cannot divide.

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.

scholarly journals Point Mutations in Transmembrane Helices 2 and 3 of ExbB and TolQ Affect Their Activities in Escherichia coli K-12

2004 ◽  
Vol 186 (13) ◽  
pp. 4402-4406 ◽  
Author(s):  
Volkmar Braun ◽  
Christina Herrmann
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Transmembrane Helix ◽  
Point Mutations ◽  
Transmembrane Helices ◽  
The Third ◽  
Form Part ◽  
K 12

ABSTRACT Replacement of glutamate 176, the only charged amino acid in the third transmembrane helix of ExbB, with alanine (E176A) abolished ExbB activity in all determined ExbB-dependent functions of Escherichia coli. Combination of the mutations T148A in the second transmembrane helix and T181A in the third transmembrane helix, proposed to form part of a proton pathway through ExbB, also resulted in inactive ExbB. E176 and T148 are strictly conserved in ExbB and TolQ proteins, and T181 is almost strictly conserved in ExbB, TolQ, and MotA.

Differential effect of amino acid starvation on polysome decay in escherichia coli

1978 ◽  
Vol 4 (1) ◽  
pp. 21-24 ◽  
Author(s):  
J. Roche ◽  
A. J. Cozzone ◽  
P. Donini ◽  
V. Santonastaso
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Differential Effect ◽  
Amino Acid Starvation

scholarly journals Regulation of Escherichia coli RelA Requires Oligomerization of the C-Terminal Domain

2001 ◽  
Vol 183 (2) ◽  
pp. 570-579 ◽  
Author(s):  
Michal Gropp ◽  
Yael Strausz ◽  
Miriam Gross ◽  
Gad Glaser
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Catalytic Domain ◽  
Mutational Analysis ◽  
Amino Acid Starvation ◽  
E Coli ◽  
Terminal Domain ◽  
Negative Effect ◽  
And Control ◽  
Two Hybrid

ABSTRACT The E. coli RelA protein is a ribosome-dependent (p)ppGpp synthetase that is activated in response to amino acid starvation. RelA can be dissected both functionally and physically into two domains: The N-terminal domain (NTD) (amino acids [aa] 1 to 455) contains the catalytic domain of RelA, and the C-terminal domain (CTD) (aa 455 to 744) is involved in regulating RelA activity. We used mutational analysis to localize sites important for RelA activity and control in these two domains. We inserted two separate mutations into the NTD, which resulted in mutated RelA proteins that were impaired in their ability to synthesize (p)ppGpp. When we caused the CTD inrelA + cells to be overexpressed, (p)ppGpp accumulation during amino acid starvation was negatively affected. Mutational analysis showed that Cys-612, Asp-637, and Cys-638, found in a conserved amino acid sequence (aa 612 to 638), are essential for this negative effect of the CTD. When mutations corresponding to these residues were inserted into the full-length relA gene, the mutated RelA proteins were impaired in their regulation. In attempting to clarify the mechanism through which the CTD regulates RelA activity, we found no evidence for competition for ribosomal binding between the normal RelA and the overexpressed CTD. Results from CyaA complementation experiments of the bacterial two-hybrid system fusion plasmids (G. Karimova, J. Pidoux, A. Ullmann, and D. Ladant, Proc. Natl. Acad. Sci. USA 95:5752–5756, 1998) indicated that the CTD (aa 564 to 744) is involved in RelA-RelA interactions. Our findings support a model in which RelA activation is regulated by its oligomerization state.

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