The aim and novelty of this paper are found in assessing the influence of inhibitors and antibiotics on intact cell MALDI-TOF mass spectra of the cyanobacterium Synechococcus sp. UPOC S4 and to check the impact on reliability of identification. Defining the limits of this method is important for its use in biology and applied science. The compounds included inhibitors of respiration, glycolysis, citrate cycle, and proteosynthesis. They were used at 1-10 μM concentrations and different periods of up to 3 weeks. Cells were also grown without inhibitors in a microgravity because of expected strong effects. Mass spectra were evaluated using controls and interpreted in terms of differential peaks and their assignment to protein sequences by mass. Antibiotics, azide, and bromopyruvate had the greatest impact. The spectral patterns were markedly altered after a prolonged incubation at higher concentrations, which precluded identification in the database of reference spectra. The incubation in microgravity showed a similar effect. These differences were evident in dendrograms constructed from the spectral data. Enzyme inhibitors affected the spectra to a smaller extent. This study shows that only a long-term presence of antibiotics and strong metabolic inhibitors in the medium at 10-5 M concentrations hinders the correct identification of cyanobacteria by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF).
- MeSH
- antibakteriální látky toxicita MeSH
- antimycin A analogy a deriváty toxicita MeSH
- azidy toxicita MeSH
- buněčné dýchání účinky léků MeSH
- chloramfenikol toxicita MeSH
- citrátový cyklus účinky léků MeSH
- deoxyglukosa toxicita MeSH
- fluoracetáty toxicita MeSH
- glykolýza účinky léků MeSH
- malonáty toxicita MeSH
- proteosyntéza účinky léků MeSH
- pyruváty toxicita MeSH
- reprodukovatelnost výsledků MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice metody MeSH
- stav beztíže MeSH
- streptomycin toxicita MeSH
- Synechococcus chemie účinky léků izolace a purifikace metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
Previously suggested antioxidant mechanisms for mitochondria-targeted plastoquinone SkQ1 included: i) ion-pairing of cationic SkQ1+ with free fatty acid anions resulting in uncoupling; ii) SkQ1H2 ability to interact with lipoperoxyl radical; iii) interference with electron flow at the inner ubiquinone (Q) binding site of Complex III (Qi), involving the reduction of SkQ1 to SkQ1H2 by ubiquinol. We elucidated SkQ1 antioxidant properties by confocal fluorescence semi-quantification of mitochondrial superoxide (Jm) and cytosolic H2O2 (Jc) release rates in HepG2 cells. Only in glycolytic cells, SkQ1 prevented the rotenone-induced enhancement of Jm and Jc but not basal releases without rotenone. The effect ceased in glutaminolytic aglycemic cells, in which the redox parameter NAD(P)H/FAD increased after rotenone in contrast to its decrease in glycolytic cells. Autofluorescence decay indicated decreased NADPH/NADH ratios with rotenone in both metabolic modes. SkQ1 did not increase cell respiration and diminished Jm established high by antimycin or myxothiazol but not by stigmatellin. The revealed SkQ1 antioxidant modes reflect its reduction to SkQ1H2 at Complex I IQ or Complex III Qi site. Both reductions diminish electron diversions to oxygen thus attenuating superoxide formation. Resulting SkQ1H2 oxidizes back to SkQ1at the second (flavin) Complex I site, previously indicated for MitoQ10. Regeneration proceeds only at lower NAD(P)H/FAD in glycolytic cells. In contrast, cyclic SkQ1 reduction/SkQ1H2 oxidation does not substantiate antioxidant activity in intact cells in the absence of oxidative stress (neither pro-oxidant activity, representing a great advantage). A targeted delivery to oxidative-stressed tissues is suggested for the effective antioxidant therapy based on SkQ1.
- MeSH
- antimycin A analogy a deriváty farmakologie MeSH
- antioxidancia farmakologie MeSH
- buňky Hep G2 MeSH
- flavinadenindinukleotid metabolismus MeSH
- glykolýza MeSH
- lidé MeSH
- methakryláty farmakologie MeSH
- mitochondrie účinky léků metabolismus MeSH
- NAD metabolismus MeSH
- oxidace-redukce MeSH
- oxidační stres MeSH
- oxidativní fosforylace * MeSH
- plastochinon analogy a deriváty farmakologie MeSH
- polyeny farmakologie MeSH
- respirační komplex I metabolismus MeSH
- respirační komplex III metabolismus MeSH
- rotenon farmakologie MeSH
- superoxidy metabolismus MeSH
- thiazoly farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In this research, a microbial endophytic strain obtained from the rhizosphere of the conifer Taxus baccata and designated as Streptomyces sp. AC35 (FJ001754.1 Streptomyces, GenBank) was investigated. High 16S rDNA gene sequence similarity suggests that this strain is closely related to S. odorifer. The major fatty acid profile of intracellular lipids was also carried out to further identify this strain. Atomic force microscopy and scanning acoustic microscopy were used to image our strain. Its major excreted substances were extracted, evaluated for antimicrobial activity, purified, and identified by ultraviolet-visible spectroscopy (UV-vis), liquid chromatography-mass spectrometry (LC-MS/MS) and nuclear magnetic resonance as the bioactive isoflavone aglycones-daidzein, glycitein and genistein. Batch cultivation, performed under different pH conditions, revealed enhanced production of antimycin components when the pH was stable at 7.0. Antimycins were detected by HPLC and identified by UV-vis and LC-MS/MS combined with the multiple reaction monitoring. Our results demonstrate that Streptomyces sp. AC35 might be used as a potential source of effective, pharmaceutically active compounds.
We investigated hydrogen peroxide production in mitochondria with low (liver, heart, brain) and high (brown adipose tissue, BAT) content of glycerophosphate dehydrogenase (mGPDH). ROS production at state 4 due to electron backflow from mGPDH was low, but after inhibition of electron transport with antimycin A high rates of mGPDH-dependent ROS production were observed in liver, heart and brain mitochondria. When this ROS production was related to activity of mGPDH, many-fold higher ROS production was found in contrast to succinate- (39-, 28-, 3-fold) or pyruvate plus malate-dependent ROS production (32-, 96-, 5-fold). This specific rate of mGPDH-dependent ROS production was also exceedingly higher (28-, 66-, 22-fold) compared to that in BAT. mGPDH-dependent ROS production was localized to the dehydrogenase+CoQ and complex III, the latter being the highest in all mitochondria but BAT. Our results demonstrate high efficiency of mGPDH-dependent ROS production in mammalian mitochondria with a low content of mGPDH and suggest its endogenous inhibition in BAT.
- MeSH
- antimycin A farmakologie MeSH
- financování organizované MeSH
- glycerolfosfátdehydrogenasa metabolismus MeSH
- hnědá tuková tkáň metabolismus MeSH
- jaterní mitochondrie metabolismus účinky léků MeSH
- křečci praví MeSH
- krysa rodu rattus MeSH
- kyselina jantarová metabolismus MeSH
- kyselina pyrohroznová metabolismus MeSH
- mitochondrie metabolismus účinky léků MeSH
- mozek metabolismus MeSH
- peroxid vodíku metabolismus MeSH
- potkani Wistar MeSH
- reaktivní formy kyslíku metabolismus MeSH
- respirační komplex III metabolismus MeSH
- srdeční mitochondrie metabolismus účinky léků MeSH
- techniky in vitro MeSH
- transport elektronů MeSH
- zvířata MeSH
- Check Tag
- křečci praví MeSH
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
Membrane fragments of two mutant strains of Paracoccus denitrificans genetically modified in the bc(1) complex have been studied for comparison of enzymic activities of succinate-cytochrome-c reductase and its components, viz. succinate dehydrogenase (Complex II) and ubiquinol-cytochrome-c reductase (Complex III) and their response to changes in concentration of succinate, cytochrome c, ionic strength, pH, temperature and sensitivity to antimycin A. The mutants synthesized and assembled the b and c hemes in the ratio characteristic for the wild type strain. The mutant strain M 71 expressing the truncated copy of cytochrome c(1) (devoid of a stretch of 150 mainly acidic amino acids) was less sensitive to increasing concentration of cytochrome c and changes in ionic strength of the medium, but maintained the original affinity to succinate and sensitivity to antimycin A. The mutant strain M 36 with an overexpressed bc(1) content showed the highest response to changes in ionic strength and physical parameters, exhibited the lowest turnover number values with succinate-cytochrome-c reductase, but positively affected the succinate dehydrogenase. In view of the interaction of the redox components in native membranes the functional analyses of separated Complexes II and III should be regarded with caution.
- MeSH
- antibakteriální látky farmakologie MeSH
- antimycin A farmakologie MeSH
- buněčná membrána enzymologie metabolismus MeSH
- elektrony MeSH
- fyziologický stres MeSH
- koncentrace vodíkových iontů MeSH
- mutace MeSH
- operon MeSH
- osmotický tlak MeSH
- oxidace-redukce MeSH
- Paracoccus denitrificans metabolismus MeSH
- respirační komplex III MeSH
- sukcinát: cytochrom c oxidoreduktasa MeSH
- teplota MeSH
The kinetics of the ubiquinol-cytochrome c reductase reaction was examined using membrane fragments and purified bc(1) complexes derived from a wild-type (WT) and a newly constructed mutant (MUT) strains of Paracoccus denitrificans. The cytochrome c(1) of the WT samples possessed an additional stretch of acidic amino acids, which was lacking in the mutant. The reaction was followed with positively charged mitochondrial and negatively charged bacterial cytochromes c, and specific activities, apparent k(cat) values, and first-order rate constant values were compared. These values were distinctly lower for the MUT fractions using mitochondrial cytochrome c but differed only slightly with the bacterial species. The MUT preparations were less sensitive to changes of ionic strength of the reaction media and showed pure first-order kinetics with both samples of cytochrome c. The reaction of the WT enzyme was first order only with bacterial cytochrome c but proceeded with a non-linear profile with mitochondrial cytochrome c. The analysis of the reaction pattern revealed a rapid onset of the reaction with a successively declining rate. Experiments performed in the absence of an electron donor indicated that electrostatic attraction could directly participate in cytochrome c reduction.
- MeSH
- antibakteriální látky metabolismus MeSH
- antimycin A metabolismus MeSH
- bakteriální proteiny genetika chemie metabolismus MeSH
- cytochromy c genetika chemie metabolismus MeSH
- financování organizované MeSH
- inhibitory enzymů metabolismus MeSH
- oxidace-redukce MeSH
- Paracoccus denitrificans chemie metabolismus MeSH
- respirační komplex III genetika chemie metabolismus MeSH
- statická elektřina MeSH
Involvement of mammalian mitochondrial glycerophosphate dehydrogenase (mGPDH, EC 1.1.99.5) in reactive oxygen species (ROS) generation was studied in brown adipose tissue mitochondria by different spectroscopic techniques. Spectrofluorometry using ROS-sensitive probes CM-H2DCFDA and Amplex Red was used to determine the glycerophosphate- or succinate-dependent ROS production in mitochondria supplemented with respiratory chain inhibitors antimycin A and myxothiazol. In case of glycerophosphate oxidation, most of the ROS originated directly from mGPDH and coenzyme Q while complex III was a typical site of ROS production in succinate oxidation. Glycerophosphate-dependent ROS production monitored by KCN-insensitive oxygen consumption was highly activated by one-electron acceptor ferricyanide, whereas succinate-dependent ROS production was unaffected. In addition, superoxide anion radical was detected as a mGPDH-related primary ROS species by fluorescent probe dihydroethidium, as well as by electron paramagnetic resonance (EPR) spectroscopy with DMPO spin trap. Altogether, the data obtained demonstrate pronounced differences in the mechanism of ROS production originating from oxidation of glycerophosphate and succinate indicating that electron transfer from mGPDH to coenzyme Q is highly prone to electron leak and superoxide generation.
- MeSH
- antimycin A analogy a deriváty farmakologie MeSH
- buněčné dýchání MeSH
- elektronová paramagnetická rezonance MeSH
- ethidium analogy a deriváty chemie MeSH
- ferrikyanidy farmakologie MeSH
- financování organizované MeSH
- glycerolfosfátdehydrogenasa metabolismus MeSH
- glycerolfosfáty metabolismus MeSH
- hnědá tuková tkáň enzymologie účinky léků ultrastruktura MeSH
- křečci praví MeSH
- mitochondrie enzymologie metabolismus účinky léků MeSH
- reaktivní formy kyslíku analýza metabolismus MeSH
- respirační komplex III metabolismus MeSH
- spotřeba kyslíku MeSH
- transport elektronů MeSH
- ubichinon metabolismus MeSH
- zvířata MeSH
- Check Tag
- křečci praví MeSH
- mužské pohlaví MeSH
- zvířata MeSH
