scholarly journals A comparison of the effects of NN′-dicyclohexylcarbodi-imide, oligomycin A and aurovertin on energy-linked reactions in mitochondria and submitochondrial particles

1968 ◽  
Vol 108 (3) ◽  
pp. 445-456 ◽  
Author(s):  
A. M. Roberton ◽  
Caroline T. Holloway ◽  
I G Knight ◽  
R B Beechey
Keyword(s):  
Potent Inhibitor ◽  
Atp Synthesis ◽  
Mitochondrial Fraction ◽  
Optimum Concentration ◽  
Submitochondrial Particles ◽  
Nicotinamide Nucleotide Transhydrogenase ◽  
Oligomycin A ◽  
Submitochondrial Particle ◽  
Site Of Action ◽  
Stimulation Of

1. The effects of dicyclohexylcarbodi-imide, oligomycin A and aurovertin on enzyme systems related to respiratory-chain phosphorylation were compared. Dicyclohexylcarbodi-imide and oligomycin A have very similar functional effects, giving 50% inhibition of ATP-utilizing and ATP-generating systems at concentrations below 0·8nmole/mg. of submitochondrial-particle protein. Aurovertin is a more potent inhibitor of ATP synthesis, giving 50% inhibition at 0·2nmole/mg. of protein. However, aurovertin is a less potent inhibitor of ATP-utilizing systems: the ATP-driven energy-linked nicotinamide nucleotide transhydrogenase is 50% inhibited at 3·0nmoles/mg. of protein and the ATP-driven reduction of NAD+ by succinate is 50% inhibited at 0·95nmole/mg. of protein. 2. With EDTA-particles (prepared by subjecting mitochondria to ultrasonic radiation at pH9 in the presence of 2mm-EDTA) the maximum stimulation of the ATP-driven partial reactions is effected by similar concentrations of oligomycin A and dicylcohexylcarbodi-imide, but the latter is less effective. The stimulatory effects of suboptimum concentrations of dicyclohexylcarbodi-imide and oligomycin A are additive. Aurovertin does not stimulate these reactions or interfere with the stimulation by the other inhibitors. 3. Dicyclohexylcarbodi-imide and oligomycin A stimulate the aerobic energy-linked nicotinamide nucleotide transhydrogenase of EDTA-particles, but the optimum concentration is higher than that required for the ATP-driven partial reactions. Aurovertin has no effect on this reaction. 4. The site of action of dicyclohexylcarbodi-imide is in CF0, the mitochondrial fraction that confers oligomycin sensitivity on F1 mitochondrial adenosine triphosphatase.

scholarly journals A kinetic analysis of the changes in fluorescence on the interaction of 8-anilinonaphthalene-l-sulphonate with submitochondrial particles

1976 ◽  
Vol 158 (2) ◽  
pp. 295-305 ◽  
Author(s):  
N Gains ◽  
A P Dawson
Keyword(s):  
Kinetic Analysis ◽  
Mitochondrial Membrane ◽  
Antimycin A ◽  
Submitochondrial Particles ◽  
Submitochondrial Particle ◽  
Fluorescence Change

A comparison of the fluorescence change on the addition of 8-anilinonaphthalene-1-sulphonate to succinate-energized submitochondrial particles with that on the addition of succinate to submitochondrial particles incubated with 8-anilinonaphthalene-1-sulphonate shows that these changes in fluorescence may be explained solely in terms of 8-anilinonaphthalene-1-sulphonate binding. This comparison does not support the proposal of an 8-anilinonaphthalene-1-sulphonate-monitored change in the conformation of submitochondrial-particle membranes [Brocklehurst, Freedman, Hancock & Radda (1970) Biochem. J.116, 721-731]. The biphasic nature of the decrease in fluorescence, which was found to follow the addition of uncoupler to submitochondrial particles incubated with ATP or succinate, or of antimycin A to submitochondrial particles incubated with succinate, does not support the existence of ‘aplectic’ and ‘symplectic’ states of the mitochondrial membrane [Barrett-Bee & Radda (1972) Biochim, Biophys. Acta 267, 211-215].

scholarly journals Alpha Carbonic Anhydrase 5 Mediates Stimulation of ATP Synthesis by Bicarbonate in Isolated Arabidopsis Thylakoids

2021 ◽  
Vol 12 ◽  
Author(s):  
Tatiana P. Fedorchuk ◽  
Inga A. Kireeva ◽  
Vera K. Opanasenko ◽  
Vasily V. Terentyev ◽  
Natalia N. Rudenko ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Arabidopsis Thaliana ◽  
Carbonic Anhydrase ◽  
Atp Synthesis ◽  
Thylakoid Membranes ◽  
Wild Type ◽  
Gene Encoding ◽  
Mutant Lines ◽  
Stimulation Of ◽  
Soluble Carbonic Anhydrase

We studied bicarbonate-induced stimulation of photophosphorylation in thylakoids isolated from leaves of Arabidopsis thaliana plants. This stimulation was not observed in thylakoids of wild-type in the presence of mafenide, a soluble carbonic anhydrase inhibitor, and was absent in thylakoids of two mutant lines lacking the gene encoding alpha carbonic anhydrase 5 (αCA5). Using mass spectrometry, we revealed the presence of αCA5 in stromal thylakoid membranes of wild-type plants. A possible mechanism of the photophosphorylation stimulation by bicarbonate that involves αCA5 is proposed.

scholarly journals Stimulation of the alternative oxidase of Neurospora crassa by Nucleoside phosphates

1980 ◽  
Vol 188 (1) ◽  
pp. 141-144 ◽  
Author(s):  
J Vanderleyden ◽  
C Peeters ◽  
H Verachtert ◽  
H Bertrand
Keyword(s):  
Neurospora Crassa ◽  
Oxidase Activity ◽  
Alternative Oxidase ◽  
Purine Nucleoside ◽  
Submitochondrial Particles ◽  
Fold Stimulation ◽  
Succinate Oxidase ◽  
Stimulation Of

The alternative-oxidase-mediated succinate oxidase activity of Neurospora crassa decreases drastically when mitochondria are fractionated into submitochondrial particles or treated with deoxycholate. The activity, however, can be completely restored in the presence of nucleoside 5′-monophosphates. The purine nucleoside 5′-monophosphates are more effective than the pyrimidine homologues. 5′-GMP gives a 10-fold stimulation of the alternative-oxidase-mediated succinate oxidase activity in submitochondrial particles. A comparison is made with the results obtained earlier with Moniliella tomentosa [Hanssens & Verachtert (1976) J. Bacteriol. 125, 825–835; Vanderleyden, Van Den Eynde & Verachtert (1980) Biochem. J. 186, 309–316].

scholarly journals Red LED Light Acts on the Mitochondrial Electron Chain of Donkey Sperm and Its Effects Depend on the Time of Exposure to Light

2020 ◽  
Vol 8 ◽  
Author(s):  
Jaime Catalán ◽  
Marion Papas ◽  
Lina Trujillo-Rojas ◽  
Olga Blanco-Prieto ◽  
Sebastián Bonilla-Correal ◽  
...  
Keyword(s):  
Red Light ◽  
Specific Inhibitor ◽  
Motile Sperm ◽  
Light Stimulation ◽  
Led Light ◽  
Mitochondrial Atp Synthase ◽  
Red Led ◽  
Oligomycin A ◽  
Rate Of Oxygen Consumption ◽  
Stimulation Of

This work aimed to investigate how stimulation of donkey sperm with red LED light affects mitochondrial function. For this purpose, freshly diluted donkey semen was stimulated with red light for 1, 5, and 10 min, in the presence or absence of oligomycin A (Omy A), a specific inhibitor of mitochondrial ATP synthase, or FCCP, a specific disruptor of mitochondrial electron chain. The results obtained in the present study indicated that the effects of red LED light on fresh donkey sperm function are related to changes in mitochondria function. In effect, irradiation of donkey sperm resulted in an increase in mitochondrial membrane potential (MMP), the activity of cytochrome C oxidase and the rate of oxygen consumption. In addition, in the absence of oligomycin A and FCCP, light-stimulation augmented the average path velocity (VAP) and modified the structure of motile sperm subpopulations, increasing the fastest and most linear subpopulation. In contrast, the presence of either Omy A or FCCP abolished the aforementioned effects. Interestingly, our results also showed that the effects of red light depend on the exposure time applied, as indicated by the observed differences between irradiation protocols. In conclusion, our results suggest that exposing fresh donkey sperm to red light modulates the function of their mitochondria through affecting the activity of the electron chain. However, the extent of this effect depends on the irradiation pattern and does not exclude the existence of other mechanisms, such as those related to thermotaxis.

Inhibition of Succinic Dehydrogenase and F0F1-ATP Synthase by 4,4'-Diisothiocyanatostilbene-2,2'-disulfonic Acid (DIDS)

1997 ◽  
Vol 52 (11-12) ◽  
pp. 799-806 ◽  
Author(s):  
Celene F. Bernardes ◽  
Jose R. Meyer-Fernandes ◽  
Orlando B. Martins ◽  
Anibal E. Vercesi
Keyword(s):  
Succinic Dehydrogenase ◽  
Atp Synthesis ◽  
Liver Mitochondria ◽  
Disulfonic Acid ◽  
Rat Liver Mitochondria ◽  
Dependent Manner ◽  
Submitochondrial Particles ◽  
Succinate Oxidation ◽  
Hydrolytic Activities ◽  
Dose Dependent

Abstract This study shows that incubation of rat liver mitochondria in the presence of the thiol/ amino reagent 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DID S) is followed by inhibition of both succinate supported respiration and oxidative phosphorylation. Half-maximal inhibition of succinic dehydrogenase activity and succinate oxidation by mitochondria was attained at 55.3 and 60.8 μm DIDS, respectively. DIDS did inhibit the net ATP synthesis and ATP ⇔ [32P]Pi exchange reaction catalyzed by submitochondrial particles in a dose-dependent manner (Ki= 31.7 μm and Ki = 32.7 μm), respectively. The hydrolytic activities of uncoupled heart submitochondrial particles and purified F 1 -ATPase were also inhibited 50% by 31.9 and 20.9 μm DIDS, respectively.

scholarly journals THE CELLULAR SITE OF ACTION OF ANGIOTENSIN

1971 ◽  
Vol 51 (2) ◽  
pp. 419-432 ◽  
Author(s):  
John B. Richardson ◽  
Aurèle Beaulnes
Keyword(s):  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Pressor Effect ◽  
Serum Factor ◽  
Morphological Studies ◽  
Exogenous Enzymes ◽  
Site Of Action ◽  
Enzyme Complexes ◽  
Stimulation Of

The site of action and the distribution of angiotensin II have been studied in the mouse. A comparison of the ratios of angiotensin-14C and inulin-3H at the time of the pressor effect reveals an extracellular pattern of distribution. Morphological studies were made using angiotensin coupled to exogenous enzymes which can be demonstrated histochemically. Coupling of angiotensin to horseradish peroxidase or cytochrome c, with glutaraldehyde or difluorodinitrodiphenylsulfone (FNPS) as the coupling agent, does not alter the pattern of its vasopressor response or that of its inactivation; nor are differences present between angiotensin and the angiotensin-enzyme complexes in the stimulation of in vitro tissue preparations. Dissociation of the complexes was shown not to occur in vitro, but the possibility of a serum factor splitting the complexes immediately after intravenous injection cannot be excluded. Since these complexes are localized on the endothelium and not on the smooth muscle at the time of maximum hypertension, the endothelium is proposed as the site of action for angiotensin.

scholarly journals Carbon monoxide-reacting haemoproteins in the mitochondrial fraction of Acanthamoeba castellanii

1980 ◽  
Vol 186 (3) ◽  
pp. 669-678 ◽  
Author(s):  
S W Edwards ◽  
D Lloyd
Keyword(s):  
Carbon Monoxide ◽  
Low Temperature ◽  
Room Temperature ◽  
Acanthamoeba Castellanii ◽  
Mitochondrial Fraction ◽  
Submitochondrial Particles ◽  
Difference Spectra ◽  
Intact Cells ◽  
Mitochondrial Fractions ◽  
Eukaryotic Organisms

1. Room-temperature (18 degrees C) CO difference spectra of mitochondrial fractions from the amoeba Acanthamoeba castellanii reveal the presence of at least four CO-reacting haemoproteins. As well as cytochrome a3, other components reacting with CO are: (i) a c-type cytochrome; (ii) a b-type cytochrome; and (iii) another a-type cytochrome. 2. The same components can be identified in low-temperature photodissociation experiments with intact cells or mitochondria. 3. The time of exposure to CO and the nature of the reductant are both important in identifying all the components present, in that the b-type cytochrome is more readily distinguished after longer exposure to CO and more of the c-type cytochrome is detectable when NADH is the reductant 4. Treatment of mitochondria with ultrasound releases two components, identifiable in low-temperature difference spectra as a c-type and a b-type cytochrome; only the latter appears to have any reaction with CO, and the CO-reacting c-type cytochrome is retained in submitochondrial particles. 5. The complexity of the CO-reacting haemoproteins in this organism is compared with the simpler systems found in other eukaryotic organisms.

The Effect of Hemicholinium-3 on Choline and Acetylcholine Levels in a Sympathetic Ganglion

1975 ◽  
Vol 53 (3) ◽  
pp. 451-457 ◽  
Author(s):  
J. C. Khatter ◽  
A. J. D. Friesen
Keyword(s):  
Superior Cervical Ganglion ◽  
Sympathetic Ganglion ◽  
Transport Systems ◽  
Cholinergic Nerves ◽  
Choline Transport ◽  
Site Of Action ◽  
Cervical Ganglion ◽  
Preganglionic Stimulation ◽  
Rate Of Decline ◽  
Stimulation Of

Preganglionic stimulation of the cat's superior cervical ganglion in the presence of hemicholinium-3 (HC-3) produced the expected depletion of acetylcholine (ACh) stores, but failed to cause a corresponding reduction in the choline content. These results suggest that either HC-3 possesses an intracellular site of action or that in lower doses it selectively inhibits a specialized choline transport system in cholinergic nerves. At a dose of 2 mg/kg, HC-3 probably blocked ACh synthesis completely in ganglia stimulated at 20 Hz. Under these conditions, there was a rapid depletion of ACh to about 50% of control levels during the first 5 min of stimulation and thereafter the rate of decline in ACh levels proceeded at a much slower pace. Since the 2 mg/kg dose of HC-3 did not raise plasma choline concentrations, it may be assumed that non-specialized choline transport systems in other tissues were not significantly inhibited by this dose of HC-3. However, when the dose of HC-3 was increased to 4 mg/kg, plasma choline levels increased by 58%.

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