Faculty Opinions recommendation of Responses of the central metabolism in Escherichia coli to phosphoglucose isomerase and glucose-6-phosphate dehydrogenase knockouts.

2004 ◽  
Author(s):  
Jacky Snoep
Keyword(s):  
Escherichia Coli ◽  
Phosphoglucose Isomerase ◽  
Central Metabolism ◽  
Glucose 6 Phosphate Dehydrogenase

scholarly journals Effect of dithiocyano-methane on hexose monophosphate pathway in the respiratory metabolism of Escherichia coli

AMB Express ◽  
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yanfeng Chen ◽  
Wenjie Ke ◽  
Huabin Qin ◽  
Siwei Chen ◽  
Limei Qin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Control Group ◽  
Respiratory Metabolism ◽  
Hexose Monophosphate ◽  
Hexose Monophosphate Pathway ◽  
Response To Stress ◽  
Glucose Decomposition ◽  
Decomposition Pathway ◽  
Glucose 6 Phosphate Dehydrogenase

Abstract This paper studied the inhibitory effects of dithiocyano-methane (DM) on the glucose decomposition pathway in the respiratory metabolism of Escherichia coli. We investigated the effects of DM on the activities of key enzymes (ATPase and glucose-6-phosphate dehydrogenase, G6PDH), the levels of key product (nicotinamide adenosine denucleotide hydro-phosphoric acid, NADPH), and gene expression in the hexose monophosphate pathway (HMP). The results showed that the minimum inhibitory concentration (MIC) and the minimum bactericide concentration (MBC) of DM against the tested strains were 5.86 mg/L and 11.72 mg/L, respectively. Bacteria exposed to DM at MIC demonstrated an increase in bacterial ATPase and G6PDH activities, NADPH levels, and gene expression in the HMP pathway compared to bacteria in the control group, which could be interpreted as a behavioral response to stress introduced by DM. However, DM at a lethal concentration of 10 × MIC affected glucose decomposition by inhibiting mainly the HMP pathway in E. coli.

Leakage of periplasmic enzymes from lipopolysaccharide-defective mutants of Salmonella typhimurium

1976 ◽  
Vol 22 (10) ◽  
pp. 1549-1560 ◽  
Author(s):  
Arun K. Chatterjee ◽  
Helen Ross ◽  
Kenneth E. Sanderson
Keyword(s):  
Acid Phosphatase ◽  
Salmonella Typhimurium ◽  
Osmotic Shock ◽  
Significant Proportion ◽  
Phosphoglucose Isomerase ◽  
Nutrient Broth ◽  
Higher Temperature ◽  
Ribonuclease I ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Smooth Strain

Mutants of Salmonella typhimurium with defects in the heptose region of the lipopolysaccharide (LPS) molecule (heptose-deficient, chemotype Re) leak periplasmic enzymes (acid phosphatase (EC 3.1.3.2), cyclic phosphodiesterase, ribonuclease I (EC 3.1.4.22), and phosphoglucose isomerase (EC 5.3.1.9) (PGI is at least partially periplasmic in E. coli and S. typhimurium; see below)) and do not leak an internal enzyme (glucose-6-phosphate dehydrogenase) into the growth medium. The extent of this leakage is markedly increased at higher temperature (42 °C). Leakage of periplasmic enzymes from the strains lacking units distal to heptose I in the LPS molecule (chemotype Rd2) occurs only at 42 °C, and not at 30 or 37 °C. The extent of leakage of these enzymes from smooth strain and mutants of other LPS chemotypes (Rc, Rd1) is not significant, and is not influenced by growth temperatures. The kinetics of leakage of periplasmic enzymes after shift to 42 °C in nutrient broth reveal an accelerated release into the medium from heptose-deficient strains of cyclic phosphodiesterase and ribonuclease I after 30 min at 42 °C, and phosphoglucose isomerase after 60 min at 42 °C; at 30 °C the rate of release of cyclic phosphodiesterase and ribonuclease I is relatively slower. After 60 min at 42 °C in nutrient broth, growth of these strains has either slowed down or stopped. In L-broth, which permits the growth of the heptose-deficient strain (SA1377) at 42 °C, leakage of cyclic phosphodiesterase and phosphoglucose isomerase occurs, whereas there is no detectable leakage of these enzymes from the isogenic smooth strain (SA 1355). Thus, leakage of the periplasmic enzymes from the heptose-deficient strain occurs with or without growth. Mg2+ (0.75 mM), sodium chloride (50 mM), and sucrose (100 mM) in nutrient broth at 42 °C prevent the leakage of these enzymes. The shedding of LPS from the heptose-deficient as well as the smooth strains is enhanced by high temperature (42 °C), whereas considerable leakage of protein occurs only in the heptose-deficient strain at 42 °C and not in the smooth strain. The smooth and heptose-deficient strains are equally sensitive to osmotic shock although a significant proportion of acid phosphatase and cyclic phosphodiesterase activities from the heptose-deficient cells grown at 42 °C comes off in the Tris-NaCl wash step suggesting a rather loose attachment of these enzymes onto the cell surface.

scholarly journals The Extracellular Death Factor: Physiological and Genetic Factors Influencing Its Production and Response in Escherichia coli

2008 ◽  
Vol 190 (9) ◽  
pp. 3169-3175 ◽  
Author(s):  
Ilana Kolodkin-Gal ◽  
Hanna Engelberg-Kulka
Keyword(s):  
Escherichia Coli ◽  
Cell Death ◽  
Genetic Factors ◽  
Strain Differences ◽  
Lethal Effect ◽  
Mixed Population ◽  
Signal Molecule ◽  
Physiological Conditions ◽  
Dehydrogenase Gene ◽  
Glucose 6 Phosphate Dehydrogenase

ABSTRACT Gene pairs specific for a toxin and its antitoxin are called toxin-antitoxin modules and are found on the chromosomes of many bacteria. The most studied of these modules is Escherichia coli mazEF, in which mazF encodes a stable toxin, MazF, and mazE encodes a labile antitoxin, MazE, which prevents the lethal effect of MazF. In a previous report from this laboratory, it was shown that mazEF-mediated cell death is a population phenomenon requiring a quorum-sensing peptide called the extracellular death factor (EDF). EDF is the linear pentapeptide NNWNN (32). Here, we further confirm that EDF is a signal molecule in a mixed population. In addition, we characterize some physiological conditions and genes required for EDF production and response. Furthermore, stress response and the gene specifying MazEF, the Zwf (glucose-6-phosphate dehydrogenase) gene, and the protease ClpXP are critical in EDF production. Significant strain differences in EDF production and response explain variations in the induction of mazEF-mediated cell death.

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