scholarly journals Oksydazy końcowe tkanek roślinnych hodowanych in vitro. Cz. II. Działanie inhibitorów oddechowych. Oksydazy miedziowe [Terminal oxidases in plant cultivated in vitro. I. The effect of respiratory inhibitors. Copper oxidases]

2015 ◽  
Vol 29 (4) ◽  
pp. 673-692 ◽  
Author(s):  
Jadwiga Michejda
Keyword(s):  
Respiratory Inhibitors ◽  
Terminal Oxidases

Radiosensitization of Hypoxic Cells of an in Vitro Tumor Model by Respiratory Inhibitors

1977 ◽  
Vol 69 (2) ◽  
pp. 359 ◽  
Author(s):  
Ralph E. Durand ◽  
John E. Biaglow
Keyword(s):  
Tumor Model ◽  
Respiratory Inhibitors

scholarly journals Expression of multiplecbb3cytochromecoxidase isoforms by combinations of multiple isosubunits inPseudomonas aeruginosa

2016 ◽  
Vol 113 (45) ◽  
pp. 12815-12819 ◽  
Author(s):  
Takehiro Hirai ◽  
Tatsuya Osamura ◽  
Masaharu Ishii ◽  
Hiroyuki Arai
Keyword(s):  
Gene Clusters ◽  
Growth Conditions ◽  
Human Pathogen ◽  
Low Oxygen ◽  
Orphan Gene ◽  
Respiratory Inhibitors ◽  
Terminal Oxidases ◽  
The Core ◽  
Oxygen Conditions ◽  
Opportunistic Human Pathogen

The ubiquitous opportunistic human pathogenPseudomonas aeruginosahas five terminal oxidases for aerobic respiration and uses them under different growth conditions. Two of them arecbb3-type cytochromecoxidases encoded by the gene clustersccoN1O1Q1P1andccoN2O2Q2P2, which are the main terminal oxidases under high- and low-oxygen conditions, respectively.P. aeruginosaalso has two orphan gene clusters,ccoN3Q3andccoN4Q4, encoding the core catalytic CcoN isosubunits, but the roles of these genes have not been clarified. We found that 16 activecbb3isoforms could be produced by combinations of four CcoN, two CcoO, and two CcoP isosubunits. The CcoN3- or CcoN4-containing isoforms were produced in the WT cell membrane in response to nitrite and cyanide, respectively. The strains carrying these isoforms were more resistant to nitrite or cyanide under low-oxygen conditions. These results indicate thatP. aeruginosagains resistance to respiratory inhibitors using multiplecbb3isoforms with different features, which are produced through exchanges of multiple core catalytic isosubunits.

scholarly journals Energy metabolism and T-cell-mediated cytolysis. I. Synergism between inhibitors of respiration and glycolysis.

1977 ◽  
Vol 146 (3) ◽  
pp. 698-709 ◽  
Author(s):  
H R MacDonald ◽  
C J Koch
Keyword(s):  
T Cell ◽  
Synergistic Effects ◽  
Energy Requirements ◽  
Target Cells ◽  
Respiratory Inhibitors ◽  
Exogenous Glucose ◽  
Glucose Analogues ◽  
Energy Dependent ◽  
Energy Pathways

The energy requirements for T-cell-mediated cytolysis have been investigated. Cytolytic thymus-derived lymphocytes (CTL) were generated in vitro in mixed leukocyte cultures and assayed for cytotoxicity on 51Cr-labeled mastocytoma target cells. Cytolysis was only slightly reduced in the absence of exogenous glucose (less than 5 micrometer) or under conditions of extreme hypoxia (less than 0.2 micrometer oxygen). Furthermore, neither the glucose analogues 2-deoxy-D-glucose and 5-thio-D-glucose nor the respiratory antagonists sodium azide and 2,4-dinitrophenol were very effective inhibitors of cytolysis when used individually. However, these glucose analogues were highly effective in inhibiting cytolysis in the absence of oxygen, and the respiratory antagonists inhibited cytolysis to a much greater extent in the absence of glucose. In addition, synergistic effects were observed when the glycolytic and respiratory inhibitors were combined. Taken together, these results indicate that T-cell-mediated cytolysis is an energy-dependent process which can be supported by either oxidative or glycolytic energy pathways.

Purine metabolism and differential inhibition of spore germination in Phytophthora infestans

1978 ◽  
Vol 24 (9) ◽  
pp. 1032-1038 ◽  
Author(s):  
M. C. Clark ◽  
D. L. Melanson ◽  
O. T. Page
Keyword(s):  
Phytophthora Infestans ◽  
Messenger Rna ◽  
Actinomycin D ◽  
Purine Metabolism ◽  
Differential Inhibition ◽  
Essential Requirement ◽  
Respiratory Inhibitors ◽  
Germination Process

An analysis of the effect of various purines and pyrimidines on the germination process in three different isolates of the late blight fungus, Phytophthora infestans, revealed increased rates of indirect germination in one isolate by adenine, hypoxanthine, and the riboside of dimethylaminopurine. This observation coupled with the capacity of sporangia of the race affected (1.2.3.4) for the uptake and interconversion of purines, as demonstrated by experiments with labelled purines under in vivo and in vitro conditions, pointed to hypoxanthine as a key intermediate in the purine metabolism directly associated with spore formation and development. This enhanced germination contrasted sharply with the almost complete arrest of indirect germination that occurred when sporangia were incubated with the purine analogue, benzimidazole, or with either of the respiratory inhibitors, sodium azide and 2,4-dinitrophenol.The pattern of differential inhibition exhibited by sporangia versus zoospores upon treatment with actinomycin D, 4-fluorouracil, or cycloheximide indicated that continued translation on preformed messenger RNA may be one essential requirement for the formation and release of zoospores, whereas their subsequent germination and development may depend upon renewed transcription as well.

scholarly journals Mitochondrial Swelling Induced by Glutathione

1959 ◽  
Vol 5 (1) ◽  
pp. 109-116 ◽  
Author(s):  
Albert L. Lehninger ◽  
Marion Schneider
Keyword(s):  
Rat Liver ◽  
Potent Inhibitor ◽  
Reduced Glutathione ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Respiratory Inhibitors ◽  
Oxidation Reduction ◽  
Optimum Ph ◽  
High Concentrations

Reduced glutathione, in concentrations approximating those occurring in intact rat liver, causes swelling of rat liver mitochondria in vitro which is different in kinetics and extent from that yielded by L-thyroxine. The effect is also given by cysteine, which is more active, and reduced coenzyme A, but not by L-ascorbate, cystine, or oxidized glutathione. The optimum pH is 6.5, whereas thyroxine-induced swelling is optimal at pH 7.5. The GSH-induced swelling is not inhibited by DNP or dicumarol, nor by high concentrations of sucrose, serum albumin, or polyvinylpyrrolidone, in contrast to thyroxine-induced swelling. ATP inhibits the GSH swelling, but ADP and AMP are ineffective. Mn-+ is a very potent inhibitor, but Mg++ is ineffective. Ethylenediaminetetraacetate is also an effective inhibitor of GSH-induced swelling. The respiratory inhibitors amytal and antimycin A do not inhibit the swelling action of GSH, but cyanide does; these findings are consistent with the view that the oxidation-reduction state of the respiratory chain between cytochrome c and oxygen is a determinant of GSH-induced swelling. Reversal of GSH-induced swelling by osmotic means or by ATP in KCl media could not be observed. Large losses of nucleotides and protein occur during the swelling by GSH, suggesting that the action is irreversible. The characteristically drastic swelling action of GSH could be prevented if L-thyroxine was also present in the medium.

scholarly journals Terminal Oxidases Are Essential To Bypass the Requirement for ResD for Full Pho Induction in Bacillus subtilis

2004 ◽  
Vol 186 (24) ◽  
pp. 8424-8432 ◽  
Author(s):  
Matthew Schau ◽  
Amr Eldakak ◽  
F. Marion Hulett
Keyword(s):  
Signal Transduction ◽  
Bacillus Subtilis ◽  
Cellular Response ◽  
Signal Transduction Network ◽  
Terminal Oxidases ◽  
Component Systems ◽  
Two Component Systems

ABSTRACT The Bacillus subtilis Pho signal transduction network, which regulates the cellular response to phosphate starvation, integrates the activity of three signal transduction systems to regulate the level of the Pho response. This signal transduction network includes a positive feedback loop between the PhoP/PhoR and ResD/ResE two-component systems. Within this network, ResD is responsible for 80% of the Pho response. To date, the role of ResD in the generation of the Pho response has not been understood. Expression of two terminal oxidases requires ResD function, and expression of at least one terminal oxidase is needed for the wild-type Pho response. Previously, our investigators have shown that strains bearing mutations in resD are impaired for growth and acquire secondary mutations which compensate for the loss of the a-type terminal oxidases by allowing production of cytochrome bd. We report here that the expression of cytochrome bd in a ΔresDE background is sufficient to compensate for the loss of ResD for full Pho induction. A ctaA mutant strain, deficient in the production of heme A, has the same Pho induction phenotype as a ΔresDE strain. This demonstrates that the production of a-type terminal oxidases is the basis for the role of ResD in Pho induction. Terminal oxidases affect the redox state of the quinone pool. Reduced quinones inhibit PhoR autophosphorylation in vitro, consistent with a requirement for terminal oxidases for full Pho induction in vivo.

scholarly journals Cys303 in the Histidine Kinase PhoR Is Crucial for the Phosphotransfer Reaction in the PhoPR Two-Component System in Bacillus subtilis

2006 ◽  
Vol 189 (2) ◽  
pp. 410-421 ◽  
Author(s):  
Amr Eldakak ◽  
F. Marion Hulett
Keyword(s):  
Inorganic Phosphate ◽  
Efficient Production ◽  
Dependent Manner ◽  
Two Component System ◽  
Component System ◽  
Terminal Oxidases ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems

ABSTRACT The PhoPR two-component system activates or represses Pho regulon genes to overcome a phosphate deficiency. The Pho signal transduction network is comprised of three two-component systems, PhoPR, ResDE, and Spo0A. Activated PhoP is required for expression of ResDE from the resA promoter, while ResD is essential for 80% of Pho induction, establishing a positive feedback loop between these two-component systems to amplify the signal received by the Pho system. The role of ResD in the Pho response is via production of terminal oxidases. Reduced quinones inhibit PhoR autophosphorylation in vitro, and it was proposed that the expression of terminal oxidases leads to oxidation of the quinone pool, thereby relieving the inhibition. We show here that the reducing environment generated by dithiothreitol (DTT) in vivo inhibited Pho induction in a PhoR-dependent manner, which is in agreement with our previous in vitro data. A strain containing a PhoR variant, PhoRC303A, exhibited reduced Pho induction and remained sensitive to inhibition by DTT, suggesting that the mechanisms for Pho reduction via PhoRC303A and DTT are different. PhoR and PhoRC303A were similar with regard to cellular concentration, limited proteolysis patterns, rate of autophosphorylation, stability of PhoR∼P, and inhibition of autophosphorylation by DTT. Phosphotransfer between PhoR∼P or PhoRC303A∼P and PhoP occurred rapidly; most label from PhoR∼P was transferred to PhoP, but only 10% of the label from PhoRC303A∼P was associated with PhoP, while 90% was released as inorganic phosphate. No difference in PhoP∼P or PhoR autophosphatase activity was observed between PhoR and PhoRC303A that would explain the release of inorganic phosphate. Our data are consistent with a role for PhoRC303 in PhoR activity via stabilization of the phosphoryl-protein intermediate(s) during phosphotransfer from PhoR∼P to PhoP, which is stabilization that is required for efficient production of PhoP∼P.

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