SUBSTRATE-DEPENDENT PHOSPHORYLATION IN RESTING CELLS OF PSEUDOMONAS AERUGINOSA

1961 ◽  
Vol 7 (1) ◽  
pp. 91-97
Author(s):  
G. A. Strasdine ◽  
J. J. R. Campbell ◽  
H. P. C. Hogenkamp ◽  
J. N. Campbell
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Electron Transport Chain ◽  
Phosphate Uptake ◽  
Growth Yield ◽  
Resting Cells ◽  
Resting Cell ◽  
Transport Chain ◽  
Oxidation Of Glucose ◽  
Phosphate Incorporation ◽  
Stimulation Of

Resting cell suspensions of Pseudomonas aeruginosa exhibited substrate-dependent phosphorylation and most of the phosphate appeared in the nucleic acid fraction. The amount of P32 incorporated was a function of substrate concentration. When equivalent amounts of glucose, gluconate, or 2-ketogluconate were used as substrate, it was found that the more oxidized substrates supported appreciably less P32 incorporation, thus indicating that phosphorylation is coincident with the passage of electrons to oxygen by way of the electron transport chain. These data serve to illustrate that the practice of determining the amount of energy available from the dissimilation of a substrate by measuring growth yield can be in error since equivalent quantities of glucose, gluconate, and 2-ketogluconate supported equal amounts of growth. The P:O ratios obtained with glucose as substrate were of the order of 0.01. Phosphorylation was not sensitive to dinitrophenol or sodium fluoride but was completely inhibited by cyanide. Chloramphenicol, at a concentration which inhibited protein synthesis, caused a twofold stimulation of phosphate incorporation. Pyocyanine, which stops the oxidation of glucose at the 2-ketogluconate stage, completely inhibited phosphate uptake. The action of pyocyanine on both oxidation and phosphorylation could be reversed by magnesium. When extracts of this organism were studied, it was found that under all conditions the addition of oxidizable substrates decreased P32 incorporation.

scholarly journals Cytochrome c550 from Pseudomonas aeruginosa

1993 ◽  
Vol 289 (1) ◽  
pp. 173-178 ◽  
Author(s):  
P Reichmann ◽  
H Görisch
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Electron Transfer ◽  
Oxygen Consumption ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Prosthetic Group ◽  
Midpoint Potential ◽  
Transport Chain ◽  
Ethanol Dehydrogenase ◽  
Soluble C

In cells of Pseudomonas aeruginosa A.T.C.C. 17933 grown on ethanol the synthesis of a soluble c-type cytochrome, together with quinoprotein ethanol dehydrogenase, is induced. The cytochrome, with an alpha-absorption band at 550 nm, was purified to homogeneity. The molecular mass of the monomeric protein is 15 kDa, the pI is 4.8, and it contains one haem prosthetic group. The midpoint potential of the autoxidizable, but not autoreducible, cytochrome is 280 mV. Cytochrome c550 mediates electron transfer between quinoprotein ethanol dehydrogenase and ferricyanide. In a system composed of membrane particles with NN‘NN’-tetramethyl-p-phenylenediamine oxidase activity and quinoprotein ethanol dehydrogenase, oxygen consumption is only observed in the presence of cytochrome c550. This indicates the participation of the cytochrome in the electron-transport chain linked to quinoprotein ethanol dehydrogenase in P. aeruginosa. The electron transport from ethanol dehydrogenase to oxygen is inhibited by myxothiazol and antimycin, indicating that a cytochrome bc1-like complex is involved.

Phosphorus deficiency and phosphate uptake in the blue-green alga Anacystis nidulans

1968 ◽  
Vol 14 (4) ◽  
pp. 341-348 ◽  
Author(s):  
J. C. Batterton ◽  
C. Van Baalen
Keyword(s):  
Phosphorus Content ◽  
Phosphate Uptake ◽  
Phosphorus Deficiency ◽  
Normal Growth ◽  
Anacystis Nidulans ◽  
Anaerobic Conditions ◽  
Atp Formation ◽  
Transport Chain ◽  
Dark Fixation ◽  
Phosphate Incorporation

The normal level of phosphorus in Anacystis nidulans is approximately 3.7 μg Pi/mm3 cells. This value fell to 0.5 μg Pi/mm3 cells under prolonged starvation. Even at low cellular phosphate levels, cells were viable and continued to divide slowly. With cells containing approximately 1.5 μg Pi/mm3 cells a rapid dark uptake (15 minutes) of 0.8 μg Pi/mm3 cells was found. Data obtained in the rapid dark fixation suggest that approximately 25% of the total cellular phosphorus is possibly bound on specific sites. Light had little effect on this first phase of phosphate uptake. The subsequent uptake to the normal phosphorus content per cell and return to normal growth rate required light and nitrogen.Coincident with the rapid dark phosphate incorporation, synthesis of ATP began and continued, rising far above the level of normal cells. The rate of ATP formation was not influenced by light, but was blocked by anaerobic conditions or several classical inhibitors of the electron transport chain.

Inhibition of enzyme induction in Pseudomonas aeruginosa by exogenous nucleotides

1978 ◽  
Vol 24 (7) ◽  
pp. 811-817 ◽  
Author(s):  
Lynda C. Kight-Olliff ◽  
J. W. Fitzgerald
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cyclic Amp ◽  
Enzyme Induction ◽  
Inhibitory Effect ◽  
Cell Suspensions ◽  
Resting Cell ◽  
Nucleoside Triphosphates ◽  
Stimulation Of

Alkylsulfatase induction in resting cell suspensions of P. aeruginosa was inhibited by exogenously supplied adenosine or by ATP (2 mM). Adenine phosphate had no effect while AMP or ADP caused a slight stimulation of induction. The inhibitory effect of ATP required the presence of added Mg2+, was not reversed by cyclic-AMP(2 mM), and was independent of the nature of the inducer. Of a number of other nucleoside triphosphates tested, only UTP (2 mM) acted as an inhibitor of induction. These nucleotides at external concentrations of 6 mM also inhibited alkylsulfatase induction in actively growing cells.

Stimulation of the electron transport chain in mitochondria isolated from rats treated with mannoheptulose or glucagon

1990 ◽  
Vol 283 (2) ◽  
pp. 278-284 ◽  
Author(s):  
Martin D. Brand ◽  
Luca D'Alessandri ◽  
Helena M.G.P.V. Reis ◽  
Roderick P. Hafner
Keyword(s):  
Electron Transport ◽  
Electron Transport Chain ◽  
Transport Chain ◽  
Stimulation Of

scholarly journals Small-Colony Variant Selection as a Survival Strategy for Staphylococcus aureus in the Presence of Pseudomonas aeruginosa

2009 ◽  
Vol 75 (21) ◽  
pp. 6910-6912 ◽  
Author(s):  
Lalitha Biswas ◽  
Raja Biswas ◽  
Martin Schlag ◽  
Ralph Bertram ◽  
Friedrich Götz
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Survival Strategy ◽  
Variant Selection ◽  
Small Colony Variant ◽  
Transport Chain ◽  
Small Colony ◽  
Selection Of

ABSTRACT Previously it has been demonstrated that Staphylococcus aureus is sensitive toward Pseudomonas-secreted exotoxins, which preferentially target the electron transport chain in staphylococci. Here it is shown that a subpopulation of S. aureus survives these respiratory toxins of P seudomonas aeruginosa by selection of the small-colony variant (SCV) phenotype. Purified pyocyanin alone causes the same effect. A hem B mutant of S. aureus survives cocultivation with P. aeruginosa without a decrease in CFU.

scholarly journals The stimulatory effects of carbon tetrachloride on peroxidative reactions in rat liver fractions in vitro. Interaction sites in the endoplasmic reticulum

1971 ◽  
Vol 123 (5) ◽  
pp. 815-821 ◽  
Author(s):  
T. F. Slater ◽  
B. C. Sawyer
Keyword(s):  
Carbon Tetrachloride ◽  
Electron Transport ◽  
Cytochrome C ◽  
Electron Transport Chain ◽  
Stimulatory Action ◽  
Interaction Sites ◽  
Nadph Cytochrome ◽  
Transport Chain ◽  
Cytochrome P 450 ◽  
Stimulation Of

1. The actions of various inhibitors of the microsomal NADPH–cytochrome P-450 electron-transport chain have been studied on the stimulatory effect of carbon tetrachloride on malonaldehyde production. 2. Carbon monoxide, p-chloromercuribenzoate, β-diethylaminoethyl-3,3′-diphenylpropyl acetate (SKF 525A) and nicotinamide did not decrease the stimulatory action of carbon tetrachloride on malonaldehyde production when present in concentrations shown to be capable of strongly inhibiting the demethylation of aminopyrine. 3. In contrast with the effects of the substances mentioned above, low concentrations of cytochrome c strongly depressed the stimulatory action of carbon tetrachloride on malonaldehyde production while increasing the endogenous rate of peroxidation. 4. Aging the microsomal suspensions at 0°C caused a rapid decrease in aminopyrine demethylation activity and in lipid peroxidation catalysed by ADP and Fe2+. The stimulation of malonaldehyde production by carbon tetrachloride was relatively unaffected, however, by aging the microsomes at 0°C for 3 days; during this period cytochrome P-450 decreased by more than 30%. 5. The conclusion is reached that the interaction between carbon tetrachloride and the NADPH–cytochrome P-450 electron-transport chain necessary for the stimulation of malonaldehyde production involves a locus near to if not identical with the NADPH–cytochrome c reductase flavoprotein.

scholarly journals Hyperthermia Increases Neurotoxicity Associated with Novel Methcathinones

Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 965 ◽  
Author(s):  
Xun Zhou ◽  
Jamal Bouitbir ◽  
Matthias E. Liechti ◽  
Stephan Krähenbühl ◽  
Riccardo V. Mancuso
Keyword(s):  
Cell Death ◽  
Electron Transport Chain ◽  
Membrane Damage ◽  
Oxygen Species ◽  
Mitochondrial Electron Transport Chain ◽  
Protective Mechanisms ◽  
Plasma Membrane Damage ◽  
Transport Chain ◽  
Clinical Consequences ◽  
Stimulation Of

Hyperthermia is one of the severe acute adverse effects that can be caused by the ingestion of recreational drugs, such as methcathinones. The effect of hyperthermia on neurotoxicity is currently not known. The primary aim of our study was therefore to investigate the effects of hyperthermia (40.5 °C) on the neurotoxicity of methcathinone (MC), 4-chloromethcathinone (4-CMC), and 4-methylmethcathinone (4-MMC) in SH-SY5Y cells. We found that 4-CMC and 4-MMC were cytotoxic (decrease in cellular ATP and plasma membrane damage) under both hyper- (40.5 °C) and normothermic conditions (37 °C), whereby cells were more sensitive to the toxicants at 40.5 °C. 4-CMC and 4-MMC impaired the function of the mitochondrial electron transport chain and increased mitochondrial formation of reactive oxygen species (ROS) in SH-SY5Y cells, which were accentuated under hyperthermic conditions. Hyperthermia was associated with a rapid expression of the 70 kilodalton heat shock protein (Hsp70), which partially prevented cell death after 6 h of exposure to the toxicants. After 24 h of exposure, autophagy was stimulated by the toxicants and by hyperthermia but could only partially prevent cell death. In conclusion, hyperthermic conditions increased the neurotoxic properties of methcathinones despite the stimulation of protective mechanisms. These findings may be important for the understanding of the mechanisms and clinical consequences of the neurotoxicity associated with these compounds.

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