Effects of ubiquinone-9 on lipids of nuclei and chromatin of the rat liver under continuous irradiation]

The influence of continuous gamma irradiation on the lipids of nuclei and chromatin of rat liver at a dose-rate of 0,129 Gy/day for 155 days (a total dose of 20 Gy) and by feeding of ubiquinone-9 has been studied. The amount of phosphatidylcholine with phosphatidylserine and phosphatidyl-ethanolamine in liver nuclei of irradiated rats was found to increase. Ubiquinone-9 had a normalizing effect. A decrease of cardiolipin was observed in the liver chromatin of irradiated rats. The amount of free fatty acids had a tendency to decrease in homogenate, nuclei and liver chromatin of irradiated rats. Ubiquinone was found to increase the amount of free fatty acids up to the control level. The amount of cholesterol in nuclei was increased after irradiation and that in chromatin tended to rise. Ubiquinone-9 significantly decreased the amount of cholesterol in nuclei and chromatin of irradiated rats.     

Ubiquinone content of eight plant species in cell culture

Crystals of ubiquinone-10 were isolated from soyabean, peanut and Ruta cell cultures, while crystals of ubiquinone-9 were obtained from rice and wheat cell cultures. These crystals also contained lesser amounts of lower and higher homologues (ubiquinone-7 to 10). The ubiquinone content of eight higher plants in cell culture was determined. Ubiquinone-9 content of rice was 680 μg per g dry wt, and this was 3–6 times higher than that of the other plants.     

Untersuchungen zur Anreicherung von Ubichinon-9 aus Lipid-Kohlenwasserstoff-Fraktionen mittels Kurzwegdestillation

Short path distillation was used for the enrichment of ubiquinone-9 from a lipid hydrocarbon extract. The main components of the lipid hydrocarbon extract were hydrocarbons of gas oil (b. p. 513 to 653 K), phosphatides, glycerides, and fatty acids. Phosphatides were isolated by extraction with acetone before distillation. The acetone soluble fraction was distilled by a pressure of ≦ 0.5 kPa and a temperature of 433 to 453 K. The concentration of the ubiquinone-9 in the residue of distillation was three times higher than in the acetone soluble fraction. Ubiquinone-9 can be obtained by a simplified separation from the enriched fraction.     

Respiratory ubiquinone-9 from Hyphomicrobium spec. Strain ZV 580

Ubiquinone-9, an ubiquinone with a side-chain containing 9 prenyl residues, was purified from Hyphomicrobium spec. strain ZV 580, and identified by thin-layer chromatography, UV spectroscopy, and mass spectrometry. The participation of the quinone in the reactions of the respiratory chain was established by observing its increasing reduction in a membrane fraction upon the addition of NADH, the exhaustion of oxygen, and in the presence of NADH plus cyanide. The degrees of reduction in these states matched those of the cytochromes b and c.     

The role of ubiquinones in the regulation of lipid metabolism in rat thymocytes

The effect of ubiquinones Q-1, Q-2, Q-8 and Q-9 on lipid metabolism in rat thymocytes in vitro was studied. The cells were incubated in a medium containing ubiquinones within the concentration range from 1 to 100 microM. A 2-fold decreased cholesterol synthesis was observed in thymocytes incubated with ubiquinone Q-9 at a concentration of exogenous ubiquinone of no less than 40 microM. Incubation of thymocytes with ubiquinones UQ-1 and UQ-2 that are characteristic of rats (40 microM and 100 microM) resulted in a decrease of cholesterol synthesis. Ubiquinone-8 had a tendency to inhibit the cholesterogenesis in rat thymocytes.     

Untersuchungen zur Anreicherung von Ubichinon-9 aus Lipid-Kohlenwasserstoff-Franktionen mittels Sepahdex LH-20

Sephadex LH-20 was tested for a potential application in the enrichment of ubiquinone-9 from a lipid-hydrocarbon-extract. The lipid-hydrocarbon-extract was isolated from yeast grown on gas oil (b. p. 240 to 380°C) as carbon-source. The main components of the lipid-hydrocarbon extract were phosphatides, glycerides, fatty acids, and hydrocarbons of gas oil. By use of Sephadex LH-20 and CHCl₃/CH₃OH (2:1)as eluent it is possible to concentrate the whole ubiquinone-9 in a special fraction both directly from the lipid-hydrocarbon-extract and from the aceton-soluble part of the extract The concentration of ubiquinone in the special fraction was ten times higher than in the raw-material and the hydrocarbons were separated completely. Ubiquinone-9 can be obtained by a simplified separation from the enriched fraction.     

Reversed-Phase High-Performance Liquid Chromatography of Prenylquinones in Green Leaves Using an Electrochemical Detector

Ubiquinone-9, -10, plastoquinone-A, -B, -C, phylloquinone and-tocopherolquinone in spinach leaf extract were separated anddetermined by reversed-phase high-performance liquid chromatographyusing an electrochemical detector. These prenylquinones wereeluted with a mixture of ethanol and methanol containing 50mM NaClO₄ and 2 mM HClO₄from an octadecyl silica column. Theelectrochemical detector could selectively detect the quinonesin the eluate, and enabled to determine even the minor quinonessuch as PQ-B and PQ-C which had not been evaluated by HPLC withan optical detector. The method is simple and sensitive to thedegree that amounts of prenylquinones could be determined aslow as 0.1 nmol. (Received June 18, 1984; Accepted September 3, 1984)     

Asymmetric binding of the high-affinity Q(H)(*)(-) ubisemiquinone in quinol oxidase (bo3) from Escherichia coli studied by multifrequency electron paramagnetic resonance spectroscopy

Ubiquinone-2 (UQ-2) selectively labeled with (13)C (I =(1)/(2)) at either the position 1- or the 4-carbonyl carbon is incorporated into the ubiquinol oxidase bo(3) from Escherichia coli in which the native quinone (UQ-8) has been previously removed. The resulting stabilized anion radical in the high-affinity quinone-binding site (Q(H)(*)(-)) is investigated using multifrequency (9, 34, and 94 GHz) electron paramagnetic resonance (EPR) spectroscopy. The corresponding spectra reveal dramatic differences in (13)C hyperfine couplings indicating a strongly asymmetric spin density distribution over the quinone headgroup. By comparison with previous results on labeled ubisemiquinones in proteins as well as in organic solvents, it is concluded that Q(H)(*)(-) is most probably bound to the protein via a one-sided hydrogen bond or a strongly asymmetric hydrogen-bonding network. This observation is discussed with regard to the function of Q(H) in the enzyme and contrasted with the information available on other protein-bound semiquinone radicals.     

Effect of ubiquinone-homologs on the sensitivity of mitochondrial ATPase to energy transfer inhibitors.

Short-chain ubiquinone (UQ-3) abolishes oligomycin sensitivity of ATPase in submitochondrial particles and the effect is reversed by long-chain ubiquinone (UQ-7). Ubiquinone-3 also abolishes DCCD sensitivity of ATPase in submitochondrial particles but the effect is not reversed by long-chain ubiquinones. These data suggest that ubiquinone interferes with energy transfer process by interaction with mitochondrial ATPase.     

微生物发酵生产辅酶Q10的研究进展

利用微生物发酵生产辅酶Q1 0 产物活性好 ,并可通过规模放大提高生产能力 ,因而颇受国内外学者的关注。文章综述菌种的选择和遗传改造 ,发酵条件的优化及其分离纯化     

Comparison between a submerged membrane bioreactor and a conventional activated sludge system on treating ammonia-bearing inorganic wastewater

A submerged membrane bioreactor (SMBR) and a conventional activated sludge system (CAS) were compared in parallel over a period of 210 days on treating synthetic ammonia-bearing inorganic wastewater under similar conditions. Except for a short period of pH control failure, almost complete conversion of NH(4)(+)?N to NO(3)(-)?N was constantly achieved over an NH(4)(+)?N concentration range from 180 to 1300mgl(-1) at a hydraulic retention time (HRT) of 24h in the SMBR, compared to an average conversion ratio of 95.0% in the CAS. Scanning electron micrographs (SEMs) demonstrated the accumulation of extracellular polymeric substances (EPSs) in the SMBR. Ubiquinone-8 (UQ-8), followed by UQ-10, UQ-7 and UQ-9, was the dominant ubiquinone in both the systems. The dominant menaquinone in the SMBR was menaquinone-6 (MK-6), while that in the CAS was MK-7, indicating that some differences existed between the two systems in terms of microbial community structure. Soluble microbial products (SMPs) tended to accumulate, and then biodegrade in SMBR.     

Solvation properties of ubiquinone-10 in solvents of different polarity

The solvation properties of ubiquinone-10 and ubiquinol-10 in a wide variety of solvents of polarity varying from alkanes to water are reported. Greatest solubility is observed in solvents of intermediate polarity and particularly where low polarity is combined with a pronounced tendency to interact with the benzoquinone substituent of the ubiquinone molecule. This includes solvents like chloroform and benzene. Ubiquinone-10 is somewhat less polar than ubiquinol-10 as judged by comparative solubilities of the two molecules. Proton-NMR chemical shift measurements and aggregation studies in selected solvents indicate that in ubiquinone-10 in the liquid phase and in solution in hydrocarbons like dodecane the molecules have a preferred association possibly involving stacking of the benzoquinone rings. Surface balance studies indicated that the surface-active character of ubiquinone-10 is relatively weak and only in a comparatively polar and highly structured solvent, formamide, was there evidence of an effect on surface tension of the solvent. The critical micelle concentratiom in this solvent was estimated to be about 5 M on the basis of surface tension measurements. Ubiquinone-10 is well known to form virtually insoluble monolayers at the air/water interface. Studies of the partition of ubiquinone-10 in binary mixtures of solvents suggest that the interaction of the benzoquinone ring substituent with structured polar solvents is considerably weaker than the internal cohesion between molecules of the solvent. No evidence on the basis of wide-angle X-ray diffraction measurements was obtained to indicate that solvent molecules were a component of the crystal lattice of ubiquinone-10 that had precipitated from solvent mixtures.     

Pelagibacterium nitratireducens sp.nov., A Marine Alphaproteobacterium Isolated from the East China Sea

A Gram-negative, rod-shaped, non-spore-forming aerobic bacterium, motile with a single polar flagellum, strain JLT2005^T, was isolated from surface seawater collected from the East China Sea and formed ivory white colonies on a rich organic medium. The strain was positive for catalase, oxidase, and urease. It grew in the presence of 0–12 % (w/v) NaCl (optimum 5 %), at 20–35 °C (optimum 25 °C), or at pH 6–10 (optimum pH 9). The major fatty acids (>10 %) were C_18:1ω7c, C_19:0ω8c cyclo, C_16:0, and C_18:0. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, and five unidentified glycolipids. Ubiquinone-10 and Ubiquinone-11 were present as the major quinones. The DNA G+C content was 74.3 mol%. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain JLT2005^T belongs to the genus Pelagibacterium in the family Hyphomicrobiaceae, class Alphaproteobacteria. The closest neighbors were Pelagibacterium halotolerans B2^T (98.7 % similarity) and Pelagibacterium luteolum 1_C16_27^T (97.1 % similarity). DNA–DNA relatedness values of strain JLT2005^T with P. halotolerans B2^T and with P. luteolum 1_C16_27^T were 31.6 and 25 %. Evidence from genotypic, chemotaxonomic, and phenotypic data shows that strain JLT2005^T represents a novel species of the genus Pelagibacterium, for which the name Pelagibacterium nitratireducens sp. nov is proposed. The type strain is JLT2005^T (=CGMCC 1.10829^T =JCM 17767^T).     

Role of PSII-L protein (psbL gene product) on the electron transfer in photosystem II complex. 1. Over-production of wild-type and mutant versions of PSII-L protein and reconstitution into the PSII core complex

To establish a system for over-production of PSII-L protein which is a component of photosystem II (PSII) complex, a plasmid designated as pMAL-psbL was constructed and expressed in Escherichia coli JM109. A fusion protein of PSII-L and maltose-binding proteins (53 kDa on SDS-PAGE) was accumulated in E. coli cells to a level of 10% of the total protein upon isopropyl--D-thiogalactopyranoside (IPTG) induction. The carboxyl-terminal part of 5.0 kDa was cleaved from the fusion protein and purified by an anion exchange column chromatography in the presence of detergents. This 5.0 kDa protein was identified as PSII-L by amino-terminal amino acid sequence analysis and the chromatographic behavior on an anion exchange gel. A few types of mutant PSII-L were also prepared by the essentially same procedure except for using plasmids which contain given mutations in psbL gene. Plastoquinone-9 (PQ-9) depleted PSII reaction center core complex consisting of D1, D2, CP47, cytochrome b-559 (cyt b-559), PSII-I and PSII-W was reconstituted with PQ-9 and digalactosyldiglyceride (DGDG) together with the wild-type or mutant PSII-L produced in E. coli or isolated PSII-L from spinach. Significant difference between the wild-type PSII-L proteins from E. coli and spinach was not recognized in the effectiveness to recover the photo-induced electron transfer activity in the resulting complexes. The analysis of stoichiometry of PQ-9 per reaction center in the PQ-9 reconstituted PS II revealed that two molecules of PQ-9 were reinserted into a reaction center independent of the presence or absence of PSII-L. These results suggest that PSII-L recovers the electron transfer activity in the reconstituted RC by a mechanism different from the stabilization of PQ-9 in the Q_A site of PSII. Ubiquinone-10 (UQ-10), but not plastoquinone-2 (PQ-2), substituted PQ-9 for recovering the PSII-L supported electron transfer activity in the reconstituted PSII reaction center complexes. The results obtained with the mutant PSII-L proteins revealed that the carboxyl terminal part rather than amino terminal part of PSII-L is crucial for recovering the electron transfer activity in the reconstituted complexes.     

Active oxygen chemistry within the liposomal bilayer. Part III: Locating Vitamin E, ubiquinol and ubiquinone and their derivatives in the lipid bilayer

We have previously shown that the location and orientation of compounds intercalated within the lipid bilayer can be qualitatively determined using an NMR chemical shift-polarity correlation. We describe herein the results of our application of this method to analogs of Vitamin E, ubiquinol and ubiquinone. The results indicate that tocopherol--and presumably the corresponding tocopheroxyl radical--reside adjacent to the interface, and can, therefore, abstract a hydrogen atom from ascorbic acid. On the other hand, the decaprenyl substituted ubiquinol and ubiquinone lie substantially deeper within the lipid membrane. Yet, contrary to the prevailing literature, their location is far from being the same. Ubiquinone-10 is situated above the long-chain fatty acid "slab". Ubiquinol-10 dwells well within the lipid slab, presumably out of "striking range" of Vitamin C. Nevertheless, ubiquinol can act as an antioxidant by reducing C- or O-centered lipid radicals or by recycling the lipid-resident tocopheroxyl radical.     

Fluorescence probe studies of the interaction of ubiquinone-10 and ubiquinol-10 with phosphatidylcholine bilayers

Ubiquinone-10 and ubiquinol-10 were incorporated into dipalmitoylphosphatidylcholine vesicles and their interaction with the phospholipids was monitored by fluorescence measurements of diphenylhexatriene used as a probe. It was found that ubiquinone-10 did not perturb the phospholipid thermotropic pretransition but ubiquinol-10 was able to do so. Although, in ethanolic solution, ubiquinone-10 was a better quencher of diphenylhexatriene than ubiquinol-10, when incorporated into phospholipid multibilayers and at temperatures above Tc, ubiquinone-10 produced a smaller decrease in the intensity of the fluorescence probe than ubiquinol-10. Furthermore, the fluorescence anisotropy of the probe was significantly increased by ubiquinol-10 but not by ubiquinone-10. It was concluded that both forms of coenzyme Q have different localizations in the phospholipid bilayer.     

Light-activated proton-motive force generation in lipid vesicles containing cytochrome b-c1 complex and bacterial reaction centres

(1) Purified bovine heart mitochondrial cytochrome b-c1 complex (ubiquinone-cytochrome c oxidoreductase) and photosynthetic reaction centres isolated from Rhodopseudomonas sphaeroides strain R-26 have been incorporated into lipid vesicles. In the presence of cytochrome c and ubiquinone-2, light activation caused a cyclic electron transfer involving both components. (2) Since cytochrome c is added outside the vesicles, it is both reduced by the cytochrome b-c1 complex and oxidised by the reaction centre on the outside of the vesicles. Ubiquinone-2, however, is reduced by the reaction centres at a site in contact with the inside of the vesicles, but the reduced form, ubiquinol-2, is oxidised by the cytochrome b-c1 complex at a site in contact with the outer aqueous phase. (3) In the presence of valinomycin plus K+, initiation of cyclic electron flow causes protons to move from inside the vesicles to the outer medium and the H +/2e- ratio was calculated to be close to 4.     

Effect of oxygen on ubiquinone-10 production by Paracoccus denitrificans

Summary Ubiquinone-10 (Q₁₀) production was measured in batch cultures of Paracoccus denitrificans grown for 8 h at increasing oxygen concentrations (0–21 % O₂ in the sparging gas). Whereas the cellular level of Q₁₀ decreased monotonically from 1.2 to 0.5 mol/g d.w., the total yield of Q₁₀ was maximal at 2.5 % O₂ and amounted to 350 nmol (0.3 mg) per L of culture.     

Lipids and Lipoprotein Complex in Photosynthetic Tissues

Lipids and pigments of photosynthetic bacteria, Rhodospirillum rubrum and Rhodopseudomonas capsulatus were examined. Common and prominent lipids in both bacteria were phosphatidyl ethanolamine and phosphatidyl glycerol. Rhodospirillum rubrum contained a special lipid containing ornithine. Their component fatty acids were straight chain saturated and monoenoic acids. No glycolipids were found in both bacteria. Ubiquinone-50 was detected in large amounts in both bacteria, and a new quinone and rhodoquinone were found in Rhodospirillum rubrum. The major carotenoids were spirilloxanthin, lycopene, and probably rhodopin. The results were compared with those of spinach and Anacystis, and discussed.     

Succinate-dependent lipid peroxidation and its prevention by reduced ubiquinone in beef heart submitochondrial particles.

When succinate and ADP-Fe3+ chelate were added to beef heart submitochondrial particles pretreated with 2-thenoyltrifluoroacetone, an inhibitor of succinate dehydrogenase of the mitochondrial respiratory chain, the formation of malondialdehyde was observed. No formation was observed without the pretreatment. Oxaloacetate competitively inhibited the malondialdehyde formation with an apparent Ki of 3.4 microM. The malondialdehyde formation seemed to be initiated at the location between the p-hydroxymercuribenzoate-sensitive site and the 2-thenoyltrifluoroacetone-sensitive site of the succinate dehydrogenase because it was inhibited by the mercurial. Ubiquinone-10 was rapidly destroyed during the malondialdehyde-forming reaction when it was in the oxidized form, while the ubiquinone was not destroyed and the malondialdehyde formation was abolished when about 50% of the ubiquinone in the particles was in the reduced state. These observations suggest that the succinate-dependent peroxidation is strongly controlled by the redox state of ubiquinone.