Meroterpenoids from a Medicinal Fungus Antrodia cinnamomea

Antrodia cinnamomea, a medicinal fungus indigenous to Taiwan, has been shown to exhibit a broad spectrum of bioactivities for the treatments of alcoholic intoxication, diarrhea, abdominal pain, and fatigue, and a number of active principles have been identified. Among the bioactive entities, clinical trials of antroquinonol and 4-acetyl antroquinonol B are being carried out for curing cancer, hypercholesterolemia, and hyperlipidemia. The total synthesis of antroquinonol has been achieved; however, investigating the structure-activity relationship of this class of compounds remained difficult due to the lack of available analogues. Twenty antroquinonols isolated from A. cinnamomea IFS006 are reported herein. Their structures were elucidated using spectral analysis and by comparison with literature values. Of these, 11 antroquinonol analogues, namely, antroquinonols N-X (1-11), were previously unreported. The growth inhibitory activity of all the antroquinonol analogues was evaluated against human A549 and PC-3 cancer cell lines, and antroquinonol A exhibited the most potent activity, with GI₅₀ values of 5.7 ± 0.2 and 13.5 ± 0.2 μM, respectively. Antroquinonols V (9) and W (10) also showed growth inhibitory activity against A549 cells with GI₅₀ values of 8.2 ± 0.8 and 7.1 ± 2.1 μM, respectively, compared to 5-fluorouracil (GI₅₀ = 4.2 ± 0.2 μM).

Induction of antroquinonol production by addition of hydrogen peroxide in the fermentation of Antrodia camphorata S-29

BACKGROUND

Antroquinonol have significantly anti-tumour effects on various cancer cells. There is still lack of reports on regulation of environmental factors on antroquinonol production by Antrodia camphorata.

RESULTS

An effective submerged fermentation method was employed to induce antroquinonol with adding H₂ O₂ . The production of antroquinonol was 57.81 mg L^-1 after fermentation for 10 days when adding 25 mmol L^-1 H₂ O₂ at day 4 of the fermentation process. Then, antroquinonol was further increased to 80.10 mg L^-1 with cell productivity of 14.94 mg g^-1 dry mycelium when the feeding rate of H₂ O₂ was adjusted to 0.2 mmol L^-1 h^-1 in the 7 L fermentation bioreactor. After inhibiting the generation of reactive oxygen species with the inhibitor diphenyleneiodoium, the synthesis of antroquinonol from A. camphorata was significantly reduced, and the yield was only 3.3 mg L^-1 .

CONCLUSION

The results demonstrated that addition of H₂ O₂ was a very effective strategy to induce and regulate the synthesis of antroquinonol in submerged fermentation. Reactive oxygen species generated by H₂ O₂ during fermentation caused oxidative stress, which induced the synthesis of antroquinonol and other chemical compounds. Moreover, it is very beneficial process to improve production and diversity of the active compounds during liquid fermentation of A. camphorata mycelium. © 2016 Society of Chemical Industry.

Coenzyme Q10 analytical determination in biological matrices and pharmaceuticals

In recent years, the analytical determination of coenzyme Q10 (CoQ10) has gained importance in clinical diagnosis and in pharmaceutical quality control. CoQ10 is an important cofactor in the mitochondrial respiratory chain and a potent endogenous antioxidant. CoQ10 deficiency is often associated with numerous diseases and patients with these conditions may benefit from administration of supplements of CoQ10. In this regard, it has been observed that the best benefits are obtained when CoQ10 deficiency is diagnosed and treated early. Therefore, it is of great value to develop analytical methods for the detection and quantification of CoQ10 in this type of disease. The methods above mentioned should be simple enough to be used in routine clinical laboratories as well as in quality control of pharmaceutical formulations containing CoQ10. Here, we discuss the advantages and disadvantages of different methods of CoQ10 analysis.

The rice bacterial pathogen Xanthomonas oryzae pv. oryzae produces 3-hydroxybenzoic acid and 4-hydroxybenzoic acid via XanB2 for use in xanthomonadin, ubiquinone, and exopolysaccharide biosynthesis

Xanthomonas oryzae pv. oryzae, the causal agent of rice bacterial blight, produces membrane-bound yellow pigments, referred to as xanthomonadins. Xanthomonadins protect the pathogen from photodamage and host-induced perioxidation damage. They are also required for epiphytic survival and successful host plant infection. Here, we show that XanB2 encoded by PXO_3739 plays a key role in xanthomonadin and coenzyme Q8 biosynthesis in X. oryzae pv. oryzae PXO99A. A xanB2 deletion mutant exhibits a pleiotropic phenotype, including xanthomonadin deficiency, producing less exopolysaccharide (EPS), lower viability and H2O2 resistance, and lower virulence. We further demonstrate that X. oryzae pv. oryzae produces 3-hydroxybenzoic acid (3-HBA) and 4-hydroxybenzoic acid (4-HBA) via XanB2. 3-HBA is associated with xanthomonadin biosynthesis while 4-HBA is mainly used as a precursor for coenzyme Q (CoQ)8 biosynthesis. XanB2 is the alternative source of 4-HBA for CoQ8 biosynthesis in PXO99A. These findings suggest that the roles of XanB2 in PXO99A are generally consistent with those in X. campestris pv. campestris. The present study also demonstrated that X. oryzae pv. oryzae PXO99A has evolved several specific features in 3-HBA and 4-HBA signaling. First, our results showed that PXO99A produces less 3-HBA and 4-HBA than X. campestris pv. campestris and this is partially due to a degenerated 4-HBA efflux pump. Second, PXO99A has evolved unique xanthomonadin induction patterns via 3-HBA and 4-HBA. Third, our results showed that 3-HBA or 4-HBA positively regulates the expression of gum cluster to promote EPS production in PXO99A. Taken together, the results of this study indicate that XanB2 is a key metabolic enzyme linking xanthomonadin, CoQ, and EPS biosynthesis, which are collectively essential for X. oryzae pv. oryzae pathogenesis.

Simultaneous analysis of circulating 25-hydroxy-vitamin D3, 25-hydroxy-vitamin D2, retinol, tocopherols, carotenoids, and oxidized and reduced coenzyme Q10 by high performance liquid chromatography with photo diode-array detection using C18 and C30 columns alone or in combination

Circulating lipid-phase micronutrients (LPM) such as 25-hydroxylated D vitamers, retinol, tocopherols, carotenoids including their isomers, and coenzyme Q10 play important roles in health maintenance and disease prevention and can serve as useful biomarkers. We developed fast, affordable, and accurate HPLC assays that simultaneously measured all above LPM in a single run using UV/VIS detection at 265nm, 295nm, and 480nm with (1) a C18 column alone; (2) a C30 column alone; or (3) each of these columns connected in series. The C18 column alone could separate all major LPM of interest in less than 17min but insufficiently resolved the lycopene isomers, the 25-hydroxylated D vitamers, lutein from zeaxanthin and β- from γ-tocopherol. The C30 column alone separated all LPM of interest including many isomeric analytes but failed to resolve the Q10 compounds, which co-eluted with carotenoids. Connecting the C18 and C30 columns in series with a detector after the C30 column and a pressure resistant detector between the columns resulted in ideal resolution and accurate quantitation of all LPM of interest but required software capable of processing the acquired data from both detectors. Connecting the C18 and C30 columns in series with exclusively one detector after the C30 column resulted in carotenoid-Q10 interferences, however, this was remedied by heart-cutting 2D-LC with a 6-port valve between the columns, which resolved all analytes in 42min. Faster run times led to some analytes not being resolved. Many variations of these methods are possible to meet the needs of individual requirements while minimizing sample material and turn-around-times.

Analytical problems with the determination of coenzyme Q10 in biological samples

The article discusses analytical problems related to the determination of coenzyme Q10 in biological samples. The assaying of coenzyme Q10 in complex samples, such as plasma, tissues, or food items requires meticulous sample preparation prior to final quantification. The process typically consists of the following steps: deproteinization, extraction, and ultimately reduction of extract volumes. At times drying under a gentle stream of neutral gas is applied. In the case of solid samples, a careful homogenization is also required. Each step of the sample preparation process can be a source of analytical errors that may lead to inaccurate results. The main aim of this work is to point to sources of analytical errors in the preparation process and their relation to physicochemical properties of coenzyme Q10. The article also discusses ways of avoiding and reducing the errors.

Measurement of oxidized and reduced coenzyme Q in biological fluids, cells, and tissues: an HPLC-EC method

Direct measure of coenzyme Q (CoQ) in biological specimens may provide important advantages. Precise and selective high-performance liquid chromatography (HPLC) methods with electrochemical (EC) detection have been developed for the measurement of reduced (ubiquinol) and oxidized (ubiquinone) CoQ in biological fluids, cells, and tissues. EC detection is preferred for measurement of CoQ because of its high sensitivity. Reduced and oxidized CoQ are first extracted from biological specimens using 1-propanol. After centrifugation, the 1-propanol supernatant is directly injected into HPLC and monitored at a dual-electrode. The EC reactions occur at the electrode surface. The first electrode transforms ubiquinone into ubiquinol, and the second electrode measures the current produced by the oxidation of the hydroquinone group of ubiquinol. The methods described provide rapid, precise, and simple procedures for determination of reduced and oxidized CoQ in biological fluids, cells, and tissues. The methods have been successfully adapted to meet regulatory requirements for clinical laboratories, and have been proven reliable for analysis of clinical and research samples for clinical trials and animal studies involving large numbers of specimens.

Critical assessment of various techniques for the extraction of carotenoids and co-enzyme Q10 from the Thraustochytrid strain ONC-T18

A variety of techniques for extracting carotenoids from the marine Thraustochytrium sp. ONC-T18 was compared. Specifically, the organic solvents acetone, ethyl acetate, and petroleum ether were tested, along with direct and indirect ultrasonic assisted extraction (probe vs bath) methods. Techniques that used petroleum ether/acetone/water (15:75:10, v/v/v) with 3 h of agitation, or 5 min in an ultrasonic bath, produced the highest extraction yields of total carotenoids (29-30.5 microg g-1). Concentrations up to 11.5 microg g-1 of canthaxanthin and 17.5 microg g-1 of beta;-carotene were detected in extracts stored for 6 weeks. Astaxanthin and echinenone were also detected as minor compounds. Extracts with and without antioxidants showed similar carotenoid concentration profiles. However, total carotenoid concentrations were approximately 8% higher when antioxidants were used. Finally, an easy-to-perform and inexpensive method to detect co-enzymes in ONC-T18 was also developed using silica gel TLC plates. Five percent methanol in toluene as a mobile phase consistently eluted co-enzyme Q10 standards and could separate the co-enzyme fractions present in ONC-T18.

Evaluation of cancer-preventive activity and structure-activity relationships of 3-demethylubiquinone Q2, isolated from the ascidian Aplidium glabrum, and its synthetic analogs

PURPOSE

3-Demethylubiquinone Q2 was isolated from the ascidian Aplidium glabrum. The cancer-preventive properties and the structure-activity relationship for 3-demethylubiquinone Q2 and 12 of its synthetic analogs are reported.

METHODS

Compounds, having one or several di- or triprenyl substitutions and quinone moieties with methoxyls in different positions, were synthesized. The cancer-preventive properties of compounds and were tested in JB6 Cl41 mouse skin cells, using a variety of assessments, including the methanethiosulfonate (MTS) assay, flow cytometry, and soft agar assay. Statistical nonparametric methods were used to confirm statistical significance.

RESULTS

All quinones tested were shown to inhibit JB6 Cl41 cell transformation, to induce apoptosis, AP-1, and NF-kappaB activity, and to inhibit p53 activity. The most promising effects were indicated for compounds containing two isoprene units in a side chain and a methoxyl group at the para-position to a polyprenyl substitution.

CONCLUSIONS

Quinones and demonstrated cancer-preventive activity in JB6 Cl41 cells, which may be attributed to the induction of p53-independent apoptosis. These activities depended on the length of side chains and on the positions of the methoxyl groups in the quinone part of the molecule.

[Classification of Methylomonas rubra sp. nov]

Strain Methylomonas rubra 15sh(T), deposited in several collections of microorganisms (NCIMB 11913(T) = UCM B-3075(T) = ACM 3303(T)), is the subject of numerous studies. However, the name of this strain is not valid, primarily due to the phenotypic similarity of the species M. rubra to the species M. methanica. The results of the present study and data available in the literature indicate that M. rubra deserves the status of a separate species. Strains of M. rubra differ from strains of M. methanica in a number of properties, such as the ability to reduce nitrates to nitrites, the structure of intracytoplasmic membranes, and the presence of a new coenzyme Q. The distinctions between the species M. rubra and M. methanica were confirmed by comparison of electrophoretic patterns of their cellular proteins, by results of DNA-DNA hybridization, and by the data from 16S rRNA gene sequencing (the level of phylogenetic homology between these two species was below 95%). Phylogenetic and phenotypic analyses showed that strains of M. rubra cannot be assigned to any species of the genus Methylomonas. Results of polyphasic analysis suggest an independent taxonomic status of strain Methylomonas rubra 15sh(T). This paper contains description of Methylomonas rubra sp. nov. with the type strain 15sh(T) = NCIMB 11913T = UCM B-3075(T) = ACM 3303(T). The nucleotide sequence of the 16S rRNA gene of strain 15sh(T) has been deposited with the GenBank database under the accession number AY995198.

A solanesyl-diphosphate synthase localizes in glycosomes of Trypanosoma cruzi

We report the cloning of a Trypanosoma cruzi gene encoding a solanesyl-diphosphate synthase, TcSPPS. The amino acid sequence (molecular mass approximately 39 kDa) is homologous to polyprenyl-diphosphate synthases from different organisms, showing the seven conserved motifs and the typical hydrophobic profile. TcSPPS preferred geranylgeranyl diphosphate as the allylic substrate. The final product, as determined by TLC, had nine isoprene units. This suggests that the parasite synthesizes mainly ubiquinone-9 (UQ-9), as described for Trypanosoma brucei and Leishmania major. In fact, that was the length of the ubiquinone extracted from epimastigotes, as determined by high-performance liquid chromatography. Expression of TcSPPS was able to complement an Escherichia coli ispB mutant. A punctuated pattern in the cytoplasm of the parasite was detected by immunofluorescence analysis with a specific polyclonal antibody against TcSPPS. An overlapping fluorescence pattern was observed using an antibody directed against the glycosomal marker pyruvate phosphate dikinase, suggesting that this step of the isoprenoid biosynthetic pathway is located in the glycosomes. Co-localization in glycosomes was confirmed by immunogold electron microscopy and subcellular fractionation. Because UQ has a central role in energy production and in reoxidation of reduction equivalents, TcSPPS is promising as a new chemotherapeutic target.

Purification of coenzyme Q10 from fermentation extract: high-speed counter-current chromatography versus silica gel column chromatography

High-speed counter-current chromatography (HSCCC) is applied to the purification of coenzyme Q(10) (CoQ(10)) for the first time. CoQ(10) was obtained from a fermentation broth extract. A non-aqueous two-phase solvent system composed of heptane-acetonitrile-dichloromethane (12:7:3.5, v/v/v) was selected by analytical HSCCC and used for purification of CoQ(10) from 500 mg of the crude extract. The separation yielded 130 mg of CoQ(10) at an HPLC purity of over 99%. The overall results of the present studies show the advantages of HSCCC over an alternative of silica gel chromatography followed by recrystallization. These advantages extend to higher purity (97.8% versus 93.3%), recovery (88% versus 74.3%) and yield (26.4% versus 23.4%). An effort to avoid the toxic, expensive solvent CH(2)Cl(2) was unsuccessful, but at least its percentage is low in the solvent system.

Supercritical carbon dioxide extraction of ubiquinones and menaquinones from activated sludge

Supercritical CO2 (scCO2) extraction, with methanol as modifier, was applied to the determination of ubiquinones and menaquinones in activated sludge. Four ubiquinones and 12 menaquinones species were identified based on retention time and UV spectrum in 0.1g dried activated sludge. The optimum extraction conditions were at a pressure of 25 MPa, a temperature of 55 degrees C, and 10% (v/v) methanol for 15 min. At this condition, the concentrations of extracted ubiquinones and menaquinones were found to be 0.181 and 0.326 micromol/g-dry-cell, respectively. The results were comparable with those obtained by organic solvent extraction based on diversity and dissimilarity indices. Furthermore, the method was evaluated in term of repeatability, which resulted in an RSD of < or =10%. The experimental results have demonstrated the technique to be simple, fast, and with less consumption of organic solvents. This work shows the potential application of supercritical CO2 extraction to microbial community analysis using quinone profile.

Analytical method for ubiquinone-9 and ubiquinone-10 in rat tissues by liquid chromatography/turbo ion spray tandem mass spectrometry with 1-alkylamine as an additive to the mobile phase

We investigated the application of 1-alkylamines, as additives to the mobile phase, to a quantification method for ubiquinone-9 (CoQ9) and ubiquinone-10 (CoQ10) in rat thigh muscle and heart using liquid chromatography-tandem mass spectrometry (LC-MS/MS). In the optimization of the analytical method, we found that 1-alkylamines mixed with CoQ9 and CoQ10 in the turbo ion sprayed solution formed the 1-alkylammonium adduct molecules of these compounds during the ionization process and that the intensity of the adduct ions was considerably higher than that of the protonated molecules ([M+H]+) of these compounds. Furthermore, we investigated a variety of 1-alkylamines in the mobile phase for LC-MS/MS analysis to select the most appropriate 1-alkylamine for higher sensitivities of CoQ9 and CoQ10. After these examinations, we found that methylamine was the most suitable additive for the mobile phase, allowing a 12.5-fold gain in signal intensity in the full ion mass spectrum compared with that without methylamine. The internal standard (IS) used was ubiquinone-11 (CoQ11) for each analyte. The analytes and IS were extracted with methanol from the tissue homogenates at neutral pH and were injected into an LC-MS/MS with a turbo ion spray interface. The calibration curves for CoQ9 (5-500 microg/g in thigh muscle and 50-10,000 microg/g in heart) and CoQ10 (1-500 microg/g in thigh muscle and 10-10,000 microg/g in heart) showed good linearity. The method was precise; the relative standard deviations of the method for rat thigh muscle were not more than 13.5 and 9.0% for CoQ9 and CoQ10, respectively, and those for rat heart were not more than 6.7 and 5.4% for CoQ9 and CoQ10, respectively. The accuracies of the method for both rat thigh muscle and heart were good, with the deviations between the nominal concentration and calculated concentration of CoQ9 and CoQ10 typically being within 12.3 and 4.3%, respectively. This method provided reliable concentration levels for CoQ9 and CoQ10 in rat thigh muscle and heart.

Cryptococcus taeanensis sp. nov., a new anamorphic basidiomycetous yeast isolated from a salt farm

Cryptococcus taeanensis, a new anamorphic yeast species originating from a salt farm on the Taean peninsula in Korea, is described. Strain 3-12(T) grew by budding, contained ubiquinone Q-10 and xylose in cell hydrolysates, utilized d-glucuronate and did not ferment D-glucose. A molecular phylogenetic analysis based on the large-subunit rRNA D1/D2 domain and ITS region sequences placed C. taeanensis near Auriculibuller fuscus and Bullera japonica, recently proposed taxa of the Tremellales. However, these species were distinguishable based on standard physiological tests used for yeast identification, with characteristics including the assimilation of L-sorbose, absence of ballistoconidia, no arbutin hydrolysis and no growth in the presence of 0.01 % cycloheximide. The isolate exhibited the typical physiology of the genus Cryptococcus Vuillemin, but its large-subunit rRNA D1/D2 domain sequence was clearly distinct from previously described species in the genus. Therefore, on the basis of these results, Cryptococcus taeanensis sp. nov. is proposed; the type strain is 3-12(T) (=KCTC 17149(T) = CBS 9742(T)).

Sphingopyxis baekryungensis sp. nov., an orange-pigmented bacterium isolated from sea water of the Yellow Sea in Korea

A Gram-negative, motile, slightly halophilic bacterial strain, SW-150T, was isolated from sea water of the Yellow Sea, Korea, and was characterized by a polyphasic taxonomic approach. Strain SW-150T grew optimally at 25–30 °C and in the presence of 2 % (w/v) NaCl. The isolate could be distinguished from other Sphingopyxis species in producing an orange pigment. It contained ubiquinone-10 as the predominant respiratory lipoquinone and C18 : 1 ω7c and C17 : 1 ω6c as the major fatty acids. No 3-hydroxy fatty acids were detected. Major polar lipids were sphingoglycolipid, diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The DNA G+C content was 63 mol%. Comparative 16S rRNA gene sequence analyses showed that strain SW-150T was phylogenetically affiliated to the genus Sphingopyxis of the family Sphingomonadaceae. Similarity values between the 16S rRNA gene sequences of strain SW-150T and the type strains of Sphingopyxis species ranged from 91·6 to 94·2 %, making it possible to categorize strain SW-150T as a species that is separate from previously described Sphingopyxis species. On the basis of phenotypic properties and phylogenetic distinctiveness, SW-150T (=KCTC 12231T=DSM 16222T) should be classified as the type strain of a novel Sphingopyxis species, for which the name Sphingopyxis baekryungensis sp. nov. is proposed.

Pichia myanmarensis sp. nov., a novel cation-tolerant yeast isolated from palm sugar in Myanmar

Four halotolerant yeast strains, M21T, M34-1, HS054 and D41, were isolated from various foods in South-East Asia. These isolates were most closely related to Pichia anomala, with which each strain had from zero to two differences in the 26S rDNA D1/D2 domain nucleotide sequence; for this reason, they were thought to be the same as, or sister species of, P. anomala. Of the four yeast isolates, only one strain, M21T, had an 18S rDNA sequence that differed from those of P. anomala IFO 10213T and the other three isolates, having 20 substitutions and two gaps. Strain M21T showed lower cation (Li+) tolerance (⩽0·3 M LiCl) than P. anomala IFO 10213T or the other three strains (⩽0·5 M LiCl). Furthermore, the DNA–DNA hybridization data indicated that M21T was clearly distinct from P. anomala IFO 10213T and the other three isolates. The ability of strain M21T to assimilate d-arabinose distinguished it from P. anomala IFO 10213T and the other three isolates; it also differed in that it was able to grow at 37 and 40 °C. Strain M21T grew by multilateral budding, produced persistent asci, in which between one and four hat-shaped ascospores were formed, and contained ubiquinone Q-7. On the basis of this polyphasic characterization, strain M21T represents a novel species within the Q-7-containing group of the genus Pichia, for which the name Pichia myanmarensis is proposed. The type strain is M21T (=NBRC 11090T=JCM 12922T=CBS 9786T).

Thermodynamic and EPR studies of slowly relaxing ubisemiquinone species in the isolated bovine heart complex I

Previously, we investigated ubisemiquinone (SQ) EPR spectra associated with NADH-ubiquinone oxidoreductase (complex I) in the tightly coupled bovine heart submitochondrial particles (SMP). Based upon their widely differing spin relaxation rate, we distinguished SQ spectra arising from three distinct SQ species, namely SQ(Nf) (fast), SQ(Ns) (slow), and SQ(Nx) (very slow). The SQ(Nf) signal was observed only in the presence of the proton electrochemical gradient (deltamu(H)(+)), while SQ(Ns) and SQ(Nx) species did not require the presence of deltamu(H+). We have now succeeded in characterizing the redox and EPR properties of SQ species in the isolated bovine heart complex I. The potentiometric redox titration of the g(z,y,x)=2.00 semiquinone signal gave the redox midpoint potential (E(m)) at pH 7.8 for the first electron transfer step [E(m1)(Q/SQ)] of -45 mV and the second step [E(m2)(SQ/QH(2))] of -63 mV. It can also be expressed as [E(m)(Q/QH(2))] of -54 mV for the overall two electron transfer with a stability constant (K(stab)) of the SQ form as 2.0. These characteristics revealed the existence of a thermodynamically stable intermediate redox state, which allows this protein-associated quinone to function as a converter between n=1 and n=2 electron transfer steps. The EPR spectrum of the SQ species in complex I exhibits a Gaussian-type spectrum with the peak-to-peak line width of approximately 6.1 G at the sample temperature of 173 K. This indicates that the SQ species is in an anionic Q(-) state in the physiological pH range. The spin relaxation rate of the SQ species in isolated complex I is much slower than the SQ counterparts in the complex I in situ in SMP. We tentatively assigned slow relaxing anionic SQ species as SQ(Ns), based on the monophasic power saturation profile and several fold increase of its spin relaxation rate in the presence of reduced cluster N2. The current study also suggests that the very slowly relaxing SQ(Nx) species may not be an intrinsic complex I component. The functional role of SQ(Ns) is further discussed in connection with the SQ(Nf) species defined in SMP in situ.

Indirect identification of isoprenoid quinones inEscherichia coli by LC-MS with atmospheric pressure chemical ionization in negative mode

A novel analytical method was applied for identification of isoprenoid quinones in Escherichia coli by liquid chromatography atmospheric press chemical ionization mass spectrometry in negative mode (LC-NI-APCI-MS). Extraction and clean-up of sample were carried out on Sep-Pak Plus Silica solid-phase extraction cartridges. Ubiquinone-7 (UQ-7), Ubiquinone-8 (UQ-8) and Mequinone-8 (MK-8) were determined directly using combined information on retention time, molecular ion mass, fragment ion masses and UV characteristic spectrometry without any standard reagent. It was found that UQ-8 was the major component of isoprenoid quinones in Escherichia coli under aerobic condition. Compared with UQ-8, the relative abundance of UQ-7 and MK-8 is only 15% and 14%, respectively. The average recoveries of UQ-6, UQ-10 and vitamin K(1) in Escherichia coli were investigated by standard spiking experiment. The recoveries were achieved in the range from 94 to 106%, and the relative standard deviations (RSD) of the triplicate analysis of the spiked samples (UQ-6, UQ-10 and vitamin K(1)) ranged from 3 to 8%. The detection limits of LC-NI-APCI-MS were estimated to be 5, 40 and 0.8 microg/g dry cell for UQ-6, UQ-10 and vitamin K(1), respectively.

Sphingomonas oligophenolica sp. nov., a halo- and organo-sensitive oligotrophic bacterium from paddy soil that degrades phenolic acids at low concentrations

The taxonomic position of a halo- and organo-sensitive, oligotrophic soil bacterium, strain S213T, was investigated. Cells were Gram-negative, non-motile, strictly aerobic, yellow-pigmented rods of short to medium length on diluted nutrient broth. When 0·1–0·4 % (w/v) NaCl was added to diluted media composed of peptone and meat extract, growth was inhibited with increasing NaCl concentration and the cells became long aberrant forms. When 6 mM CaCl2 was added, the cells grew quite normally and aberrant cells were no longer found at 0·1–0·5 % (w/v) NaCl. Chemotaxonomically, strain S213T contains chemical markers that indicate its assignment to the Sphingomonadaceae: the presence of ubiquinone Q-10 as the predominant respiratory quinone, C18 : 1 and C16 : 0 as major fatty acids, C14 : 0 2-OH as the major 2-hydroxy fatty acid and sphingoglycolipids. 16S rRNA gene sequence analysis indicated that strain S213T belongs to the genus Sphingomonas, exhibiting high sequence similarity to the 16S rRNA gene sequences of Sphingomonas mali IFO 15500T (98·3 %), Sphingomonas pruni IFO 15498T (98·0 %), Sphingomonas asaccharolytica IFO 15499T (97·9 %) and Sphingomonas echinoides DSM 1805T (97·8 %). The results of DNA–DNA hybridization experiments and its phenotypic characteristics clearly distinguished the strain from its nearest neighbours and demonstrate that strain S213T represents a novel Sphingomonas species, for which the name Sphingomonas oligophenolica sp. nov. is proposed. The type strain is S213T (=JCM 12082T=CIP 107926T).

Pseudoxanthomonas mexicana sp. nov. and Pseudoxanthomonas japonensis sp. nov., isolated from diverse environments, and emended descriptions of the genus Pseudoxanthomonas Finkmann et al. 2000 and of its type species

Three mesophilic bacteria (strains AMX 26BT, UR374_02 and 12-3T) isolated respectively from an anaerobic digester, human urine and urban riverside soil were characterized. Cells were Gram-negative, motile, non-sporulating, straight to curved rods with one polar flagellum and had a strictly respiratory metabolism with O2 as the preferential terminal electron acceptor. Phylogenetic analysis based on 16S rRNA gene sequences revealed that all strains clustered within the Xanthomonadaceae branch of the Proteobacteria. Isolates AMX 26BT and UR374_02 exhibited 100 % 16S rRNA gene sequence similarity and both were related to strain 12-3T (99·6 % similarity). The closest relative of all the isolates was Pseudoxanthomonas broegbernensis DSM 12573T (similarity 97·1–97·5 %), and they were equidistantly related to Xanthomonas species (95·4–96·6 %), Stenotrophomonas species (95·3–96·1 %) and Pseudoxanthomonas taiwanensis ATCC BAA-4040T (95·3–95·4 %). Chemotaxonomic and biochemical data (branched-chain cellular fatty acid pattern without C13 : 0 iso 3-OH, ubiquinone with eight isoprenoid units, limited range of substrates used, ability to reduce nitrite but not nitrate with the production of N2O) supported their affiliation to the genus Pseudoxanthomonas. The results of DNA–DNA hybridization and/or phenotypic analysis allowed them to be differentiated from the two Pseudoxanthomonas species with validly published names and showed that strain 12-3T was genomically and phenotypically distinct from the other two isolates. On the basis of these results, two novel species of the genus Pseudoxanthomonas are proposed: Pseudoxanthomonas mexicana sp. nov., consisting of strains AMX 26BT (=ATCC 700993T=CIP 106674T=JCM 11524T) (type strain) and UR374_02 (=DSM 15133), and Pseudoxanthomonas japonensis sp. nov., consisting of strain 12-3T (=CCUG 48231T=CIP 107388T=JCM 11525T). The report of these two novel species leads to the emendation of the description of the genus Pseudoxanthomonas and the re-evaluation of the phenotype of P. broegbernensis DSM 12573T necessitates the emendation of its description.

Shewanella marisflavi sp. nov. and Shewanella aquimarina sp. nov., slightly halophilic organisms isolated from sea water of the Yellow Sea in Korea

Two Gram-negative, motile, non-spore-forming, rod-shaped organisms, strains SW-117T and SW-120T, were isolated from sea water of the Yellow Sea in Korea and subjected to a polyphasic taxonomic study. Strains SW-117T and SW-120T simultaneously contained both menaquinones (MK) and ubiquinones (Q) as isoprenoid quinones; the predominant menaquinone was MK-7 and the predominant ubiquinones were Q-7 and Q-8. The major fatty acid detected in the two strains was iso-C15 : 0. The DNA G+C content of strains SW-117T and SW-120T was 51 and 54 mol%, respectively. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains SW-117T and SW-120T fall within the radiation of the cluster comprising Shewanella species. Strains SW-117T and SW-120T showed a 16S rRNA gene sequence similarity of 97·4 % and a DNA–DNA relatedness level of 10·1 %. Strains SW-117T and SW-120T exhibited 16S rRNA gene sequence similarity levels of 93·8–98·5 % and 92·4–97·0 %, respectively, to Shewanella species. Strain SW-117T exhibited DNA–DNA relatedness levels of 8·3–20·3 % to the type strains of six phylogenetically related Shewanella species. On the basis of phenotypic, phylogenetic and genetic data, strains SW-117T and SW-120T were classified in the genus Shewanella as two distinct novel species, for which the names Shewanella marisflavi sp. nov. (type strain, SW-117T=KCCM 41822T=JCM 12192T) and Shewanella aquimarina sp. nov. (type strain, SW-120T=KCCM 41821T=JCM 12193T) are proposed, respectively.

Light-Harvesting Complex 1 Stabilizes P+QB- Charge Separation in Reaction Centers of Rhodobacter sphaeroides

The kinetics of charge recombination following photoexcitation by a laser pulse have been analyzed in the reaction center-light harvesting complex 1 (RC-LH1) purified from the photosynthetic bacterium Rhodobacter sphaeroides. In RC-LH1 core complexes isolated from photosynthetically grown cells P(+)Q(B)(-) recombines with an average rate constant, k approximately 0.3 s(-1), more than three times smaller than that measured in RC deprived of the LH1 (k approximately 1 s(-1)). A comparable, slowed recombination kinetics is observed in RC-LH1 complexes purified from a pufX-deleted strain. Slowing of the charge recombination kinetics is even more pronounced in RC-LH1 complexes isolated from wild-type semiaerobically grown cells (k approximately 0.2 s(-1)). Since the kinetics of P(+)Q(A)(-) recombination is unaffected by the presence of the antenna, the P(+)Q(B)(-) state appears to be energetically stabilized in core complexes. Determinations of the ubiquinone-10 (UQ(10)) complement associated with the purified RC-LH1 complexes always yield UQ(10)/RC ratios larger than 10. These quinone molecules are functionally coupled to the RC-LH1 complex, as judged from the extent of exogenous cytochrome c(2) rapidly oxidized under continuous light excitation. Analysis of P(+)Q(B)(-) recombination, based on a kinetic model which considers fast quinone equilibrium at the Q(B) binding site, indicates that the slowing down of charge recombination kinetics observed in RC-LH1 complexes cannot be explained solely by a quinone concentration effect and suggests that stabilization of the light-induced charge separation is predominantly due to interaction of the Q(B) site with the LH1 complex. The high UQ(10) complements detected in RC-LH1 core complexes, but not in purified light-harvesting complex 2 and in RC, are proposed to reflect an in vivo heterogeneity in the distribution of the quinone pool within the chromatophore bilayer.

Ubiquinone systems in fungi. V. Distribution and taxonomic implications of ubiquinones in Eurotiales, Onygenales and the related plectomycete genera, except for Aspergillus, Paecilomyces, Penicillium, and their related teleomorphs

The ubiquinone (coenzyme Q) systems were determined for 176 teleomorphic isolates, 14 anamorphic isolates, and three samples of fruit-bodies of Dendrosphaera eberhardtii, which belonged to Eurotiales, Onygenales, and related taxa. In Eurotiales, Ascosphaera had Q-9, whereas Bettsia had Q-10. All isolates of Monascaceae had the Q-10 system, whereas those of four genera of Pseudeurotiaceae had the Q-10(H2) system. The Q-10(H2) system was found in genera of Trichocomaceae, except for Aspergillus, Penicillium, Paecilomyces, and their related taxa. However, Thermoascus had the Q-9 system. In Onygenales, members of Arthrodermataceae had Q-9, and those of Gymnoascaceae had Q-10(H2). Isolates of Myxotrichaceae were characterized by Q-10(H2) with few exceptions, which had Q-10. The quinones of Onygenaceae belonged to complex systems, i.e., Q-9, 0-10 and 0-10(H2), and a combination of two systems. Families Onygenaceae and Trichocomaceae are likely a phylogenetic heterogeneity. Ubiquinone analysis provides a very useful criterion of great promise for classifying eurotialean taxa and also for identifying their isolates.

[Taxonomy and ecology of the genus Candida]

Candida is a heterogeneous genus which contains about a quarter of all yeast species. It includes not only species of uncertain affiliation but also unrelated strains whose phylogenetic relationships have not been resolved. A great variety of CoQ types are present in the genus, the mol % G + C ranges from 30-63%, and species that were found to sporulate have teleomorphic counterparts in 11 different genera. Candida species are mainly associated with plants, rotting vegetation, with insects which feed on plants or with food. In line with this, 71% of Candida species utilize xylose (wood degradation), 57% of species use cellobiose (cellulose degradation), 29% oxidize aliphatic hydrocarbons (components of plant cuticula), 27% of species degrade starch as a plant storage material, and 7% utilize methanol as a possible metabolite from pectin catabolism. 85% of species require individual vitamins produced mainly in plant materials. 65% of Candida species are not able to grow at temperatures of 37 degrees C. In comparison only relatively few species occur normally in humans and other warm blooded animals. About 16% of type strains and selected strains for comparative purposes (CBS) were isolated from human specimens. Perhaps up to 10% of Candida species may be of medical importance, though this has so far only been clearly demonstrated for less than 5% of currently known species.

Rhodoquinone is synthesized de novo by Fasciola hepatica

Most adult parasitic helminths have an anaerobic energy metabolism in which fumarate is reduced to succinate by fumarate reductase. Rhodoquinone (RQ) is an essential component of the electron transport associated with this fumarate reduction, whereas ubiquinone (UQ) is used in the aerobic energy metabolism of parasites. Not known yet, however, is the RQ and UQ composition during the entire life cycle nor the origin of RQ in parasitic helminths. This report demonstrates the essential function of RQ in anaerobic energy metabolism during the entire life cycle of Fasciola hepatica, as the amount of RQ present reflected the importance of fumarate reduction in various stages. We also studied the origin of RQ, as earlier studies on the protozoan Euglena gracilis suggested that RQ is synthesized from UQ. Therefore, in parasitic helminths RQ might be synthesized by modification of UQ obtained from the host. However, we demonstrated that in F. hepatica adults RQ was not produced by modification of UQ obtained from the host but that RQ was synthesized de novo, as (i) the chain-length of the quinones of F. hepatica adults was not related to the chain length of the quinone of the host, (ii) despite many attempts we could never detect any in vitro conversion of UQ9 into RQ9 or into UQ10, neither by intact adult flukes nor by homogenates of F. hepatica adults and (iii) F. hepatica adults used mevalonate as precursor for the synthesis of RQ. We also showed that the rate of quinone synthesis in F. hepatica adults was comparable to that in the free-living nematode Caenorhabditis elegans. These results prompted the suggestion that RQ is synthesized via a pathway nearly identical to that of UQ biosynthesis: possibly only the last reaction differs.

Simultaneous reversed-phase high-performance liquid chromatographic separation of non-polar isoprenoid lipids and their determination

A procedure for the rapid identification and determination of non-polar isoprenoid lipids from animal tissues was developed. The complete determination can be carried out by reversed-phase HPLC of just two samples. The first, extracted from unaltered tissues and suitably processed by column chromatography, provides information about free cholesterol, cholesteryl esters, coenzymes Q, free dolichols and dolichyl esters. The second, obtained from saponified tissues, can be used to detect both total cholesterol and total dolichols. Specific calibration graphs were constructed for the determination of the different constituents.

Energy-dependent Complex I-associated ubisemiquinones in submitochondrial particles

Two distinct species of Complex I-associated ubisemiquinones (SQNf and SQNs) were detected by cryogenic EPR analysis of tightly coupled submitochondrial particles oxidizing NADH or succinate under steady-state conditions. The g = 2.00 signals from both fast-relaxing SQNf (P1/2 = 170 mW at 40 K) and slow-relaxing SQNs (P1/2 = 0.7 mW) are sensitive to uncouplers, rotenone and thermally induced deactivation of Complex I. At higher temperatures the SQNf signal is broadened and only the SQNs signal is seen (P1/2 = 7 mW at 105 K). The spin-spin interaction between SQNf and the iron-sulfur cluster N2 was detected as split peaks of the g parallel 2.5 signal with a coupling constant of 1.65 mT, revealing their mutual distance of 8-11 A. The data obtained are consistent with a model in which N2 and two interacting bound ubisemiquinone species are spatially arranged within the hydrophobic domain of Complex I, participating in the vectorial proton translocation.

[Inhibitory effect of bithionol on NADH-fumarate reductase in ascarides]

To elucidate the mechanism of anthelmintic action of bithionol, the inhibitory effect of the drug on NADH-fumarate reductase (NADH-FR) of Ascaris lumbricoides suum was examined. NADH-FR, an enzyme of anaerobic carbohydrate metabolic pathway was solubilized from the mitochondria of the worm's muscle with deoxycholate, and then partially purified with the monoethanolamine-Sepharose 4B column chromatography. Rhodoquinone (RQ), which is required for the electron transfer from NADH to fumarate, was separated from the enzyme protein and phospholipids. Although the enzyme protein fraction eluted from the above column did not show NADH-FR activity, this enzyme was reactivated by the addition of purified RQ and phosphatidylcholine. The IC50 value of bithionol for reconstituted NADH-FR was 18 +/- 2 microM. The inhibition type was competitive to RQ. Bithionol inhibited at most 30% NADH-ferricyanide reductase, which did not require RQ, even at high concentration of 150 microM. These results suggest that the pharmacological action of bithionol, a phenolic anthelmintic, depends on the inhibition of the electron transport system by the competition with RQ.

Reevaluation of the teleomorph of the genus Histoplasma by ubiquinone systems

Ubiquinone systems of the genus Histoplasma and Blastomyces dermatitidis were examined and the relationship between the two genera, Emmonsiella and Ajellomyces, was discussed. Ubiquinone systems have been adopted as a useful taxonomic criteria at the generic level for fungi. We investigated ubiquinone systems of sexual and asexual strains of Histoplasma species and Blastomyces dermatitidis. All the strains of the former group had dihydrogenated ubiquinone-10(Q-10(H2] as the major isoprenologue, while the latter had ubiquinone-10(Q-10). From the result, it was concluded that the teleomorph of Histoplasma species should be brought back to Emmonsiella.

Subunit IV (Mr = 14,384) of the cytochrome b-c1 complex from Rhodobacter sphaeroides. Cloning, DNA sequencing, and ubiquinone binding domain

The Rhodobacter sphaeroides gene encoding subunit IV of the cytochrome b-c1 complex (fbcQ) was cloned and sequenced. The fbcQ cistron is 372 base pairs long and encodes 124 amino acid residues. The molecular mass of subunit IV, deduced from the nucleotide sequence, is 14,384 Da. A hydropathy plot of the predicted amino acid sequence revealed only one transmembrane helix; it is near the C-terminal end. The 3-azido-2-methyl-5-methoxy-6-(3,7-dimethyl[3H]octyl)-1,4-benzoquinone ([3H]azido-Q)-labeled subunit IV was isolated from the [3H]-azido-Q-treated cytochrome b-c1 complex. A ubiquinone-binding peptide was obtained by digesting the labeled subunit IV with V8 protease followed by high performance liquid chromatography separation. Amino acid analysis and partial N-terminal sequencing of this ubiquinone-binding peptide revealed that it corresponded to residues 77-124 of subunit IV. Based on the hydropathy profile and predicted tendency to form alpha-helices and beta-sheets, we propose a structural model for subunit IV. In this model the ubiquinone-binding domain is located near the surface of the membrane.

Immunochemical study of subunit VI (Mr 13,400) of mitochondrial ubiquinol-cytochrome c reductase

A preparation containing the Mr 13,400 protein (subunit VI), phospholipid, and ubiquinone was isolated from bovine heart mitochondrial ubiquinol-cytochrome c reductase by a procedure involving Triton X-100 and urea solubilization, calcium phosphate-cellulose column chromatography at different pHs, acetone precipitation, and decanoyl-N-methylglucamide-sodium cholate extraction. The protein in this preparation corresponds to subunit VI of ubiquinol-cytochrome c reductase resolved in the sodium dodecyl sulfate-polyacrylamidce gel electrophoresis system of Schägger et al. (1987, FEBS Lett. 21, 161-168) and has the same amino acid sequence as that of the Mr 13,400 protein reported by Wakabayashi et al. (1985, J. Biol. Chem. 260, 337-343). The phospholipid and ubiquinone present in the preparation copurify with but are not intrinsic components of, the Mr 13,400 protein. This preparation has a potency and behavior identical to that of a free phospholipid preparation in restoring activity to delipidated ubiquinol-cytochrome c reductase. Antibodies against Mr 13,400 react only with Mr 13,400 protein and complexes which contain it. They do not inhibit intact, lipid-sufficient ubiquinol-cytochrome c reductase. However, when delipidated ubiquinol-cytochrome c reductase is incubated with antibodies prior to reconstitution with phospholipid, a 55% decrease in the restoration activity is observed, indicating that the catalytic site-related epitopes of the Mr 13,400 protein are buried in the phospholipid environment. Antibodies against Mr 13,400 cause an increase of apparent Km for ubiquinol-2 in ubiquinol-cytochrome c reductase. When mitoplasts or submitochondrial particles are exposed to a horseradish peroxidase conjugate of the Fab' fragment of anti-Mr 13,400 antibodies, peroxidase activity is found mainly in the submitochondrial particles preparation; little activity is detected in mitoplasts. This suggests that the Mr 13,400 protein is extruded toward the matrix side of the membrane.

Coenzyme Q systems in ascomycetous black yeasts

72 Strains belonging to 44 species of ascomycetous black yeasts were analyzed for their coenzyme Q systems. Prevalent were Q-10 and dihydrogenated Q-10 systems. Members of the Dothidealean suborder Dothideineae have Q-10(H2), while those belonging to the suborder Pseudosphaeriineae mostly have Q-10. The anamorph genus Exophiala Carmichael and the teleomorph genus Capronia Sacc. seem to be heterogeneous.

Respiration of bloodstream forms of the parasite Trypanosoma brucei brucei is dependent on a plant-like alternative oxidase

CoQ links the sn-glycerol-3-phosphate dehydrogenase and oxidase components of the cyanide-insensitive, non-cytochrome-mediated respiratory system of bloodstream African trypanosomes. In this and other characteristics, their respiratory system is similar to the alternative oxidase of plants. The parasites contain 206 ng of CoQ9 mg protein-1 which co-sediments with respiratory activity. The redox state of this CoQ responds in a manner consistent with respiratory function: 60% being in the reduced form when substrate is available and the oxidase is blocked; 13% being in the reduced form when the oxidase is functioning and there is no substrate. The addition of CoQ to aceton-extracted cells stimulates salicylhydroxamic acid-sensitive respiration by 56%. After inhibition of respiration by digitonin-mediated dispersal of the electron transport components, liposomes restore 40% of respiratory activity while liposomes containing CoQ restore 66% of this activity. A less hydrophobic analogue, reduced decyl CoQ, serves as a direct substrate for the trypanosome oxidase supporting full salicylhydroxamic acid-sensitive respiration. After digitonin disruption of electron transport, the nonreduced form of this synthetic substrate can reestablish the chain by accepting electrons from dispersed sn-glycerol-3-phosphate dehydrogenase and transferring them to the dispersed oxidase. Similarities between the alternative oxidase of plants and the oxidase of the trypanosome respiratory system include: mitochondrial location, lack of oxidative phosphorylation, linkage of a dehydrogenase and an oxidase by CoQ, lack of sensitivity to a range of mitochondrial inhibitors, and sensitivity to a spectrum of inhibitors which selectively block transfer of electrons from reduced CoQ to the terminal oxidase but do not block electron transfer to the cytochrome bc1 complex of the mammalian cytochrome chain.

Isolation and characterization of isoprene mutants of Escherichia coli

Isoprenoid compounds are found in all organisms. In Escherichia coli the isoprene pathway has three distinct branches: the modification of tRNA; the respiratory quinones ubiquinone and menaquinone; and the dolichols, which are long-chain alcohols involved in cell wall biosynthesis. Very little is known about procaryotic isoprene biosynthesis compared with what is known about eucaryote isoprene biosynthesis. This study approached some of the questions about isoprenoid biosynthesis and regulation in procaryotes by isolating and characterizing mutants in E. coli. Mutants were selected by determining their resistance to low levels of aminoglycoside antibiotics, which require an electron transport chain for uptake into bacterial cells. The mutants were characterized with regard to their phenotypes, map positions, enzymatic activities, and total ubiquinone content. In particular, the enzymes studied were isopentenyldiphosphate delta-isomerase (EC 5.3.3.2), farnesyldiphosphate synthetase (EC 2.5.1.1), and higher prenyl transferases.

[Ubiquinone (Q). Distribution, regulation of biosynthesis and methods of isolation]

The data available in literature and results of own studies on distribution and localization of ubiquinone (Q), promising sources and methods of its isolation from tissues of animal and microorganisms are revised. Conditions of microorganism cultivation to intensity ubiquinone biosynthesis as well as methods of its production are revised.

Isolation and identification of coenzyme Q from Leishmania donovani

Crystalline coenzyme Q (CoQ) was obtained from Leishmania donovani promastigotes by extraction of the unsaponifiable material with hexane, chromatography on a Florisil column and crystallization from ethanol. Crystalline CoQ in ethanol revealed an ultraviolet-peak, at 275 nm, which disappeared upon reduction with NaBH4. Polarographic and mass fragmentographic measurements were characteristic of CoQ homologs. Reversed-phase thin-layer chromatography revealed that it is CoQ9.

Ubiquinone biosynthesis by the microsomal fraction from rat liver

The distribution and biosynthesis of ubiquinone were investigated in vivo in rats and using liver slices. In addition to mitochondria, Golgi vesicles and lysosomes also contain large amounts of this lipid, and even the plasma membrane, peroxisomes and microsomes demonstrate easily measurable amounts. The spectral and chromatographic properties of microsomal ubiquinone were identical to those of its mitochondrial counterpart. When pentane was used to deplete beef heart submitochondrial particles of ubiquinone, NADH and succinate oxidase activities could be restored by reincorporation of microsomal ubiquinone. Injection of [3H]mevalonate into the portal vein of rats and incubation of liver slices with [3H]mevalonate and [3H]- and [14C]tyrosine demonstrated that labeling of mitochondrial ubiquinone was initially much lower than labeling of the microsomal lipid. Furthermore, intraportal injection of [3H]mevalonate resulted in the rapid appearance of labeled ubiquinone in the blood. These results indicate that ubiquinone is synthesized not only in mitochondria, but also on the endoplasmic reticulum of rat liver.

A possible mode of solubilization of coenzyme Q10 with HCO-60

The redox level of [14C]coenzyme Q10 solubilized with HCO-60 in the livers of guinea pigs at 24 h after intravenous injection was approximately 1/4 (18.2% vs. 63.4%) of that of [14C]coenzyme Q10 solubilized with ethanol-water (1:5 by vol). Further, the redox level of coenzyme Q10 (Q10) solubilized with HCO-60 or ethanol-water was 20.2 or 82.3%, respectively, after a 30-min incubation in the liver cytosol. Q10 solubilized with HCO-60 was thus reduced only slightly in vivo or in vitro. The critical micelle concentrations of HCO-60 in the absence and presence of Q10 were 0.02 and 0.002% (w/v), respectively. The concentrations of HCO-60 micelles containing Q10 were estimated to be 0.0048% (w/v) in the incubation mixture with cytosol and 0.0041% (w/v) in blood circulation. These results suggest that HCO-60 micelles containing Q10 would remain more stable not only in blood circulation but also in tissues as compared with ethanol-water emulsion. A possible mode of solubilization of Q10 is discussed.

Demonstration of a collisional interaction of ubiquinol with the ubiquinol-cytochrome c2 oxidoreductase complex in chromatophores from Rhodobacter sphaeroides

Ubiquinone-10 can be extracted from lyophilized chromatophores of Rhodobacter sphaeroides (previously called Rhodopseudomonas sphaeroides) without significant losses in other components of the electron-transfer chain or irreversible damages in the membrane structure. The pool of ubiquinone can be restored with exogenous UQ-10 to sizes larger than the ones in unextracted membranes. The decrease in the pool size has marked effects on the kinetics of reduction of cytochrome b-561 induced by a single flash of light and measured in the presence of antimycin. The initial rate of reduction, which in unextracted preparations increases on reduction of the suspension over the Eh range between 170 and 100 mV (pH 7), is also stimulated in partially UQ-depleted membranes, although at more negative Eh's. When the UQ pool is completely extracted the rate of cytochrome (Cyt) b-561 reduction is low and unaffected by the redox potential. In membranes enriched in UQ-10 above the physiological level the titration curve of the rate of Cyt b-561 reduction is displaced to Eh values more positive than in controls. This effect is saturated when the size of the UQ pool is about 2-3 times larger than the native one. The reduction of Cyt b-561 always occurs a short time after the flash is fired; also the duration of this lag is dependent on Eh and on the size of the UQ pool. A decrease or an increase in the pool size causes a displacement of the titration curve of the lag to more negative or to more positive Eh's, respectively. Similarly, the lag becomes Eh independent and markedly longer than in controls when the pool is completely extracted. These results demonstrate that the rate of turnover of the ubiquinol oxidizing site in the b-c1 complex depends on the actual concentration of ubiquinol present in the membrane and that ubiquinol from the pool is oxidized at this site with a collisional mechanism. Kinetic analysis of the data indicates that this reaction obeys a Michaelis-Menten type equation, with a Km of 3-5 ubiquinol molecules per reaction center.

Isolation and characterization of a novel coenzyme Q from some methane-oxidizing bacteria

The respiratory quinone composition of 18 strains of obligate methane-utilizing bacteria was examined. All of the strains contained lipoquinones which on examination by tlc co-chromatographed with coenzyme Q. On the basis of chromatographic and physicochemical analyses the lipoquinones produced by 10 of the strains corresponded to Q-8. Reverse-phase partition and argentation hplc demonstrated the quinone produced by the remaining 8 strains did not correspond to any known coenzyme Q prenologue. On the basis of mass spectrometry, 1H and 13C nuclear magnetic resonance spectrometry the novel quinone was shown to correspond to 2,3-dimethoxy-5-methyl-6-(18-methylene-3,7, 11,15,19,23,27,31-octamethyldotriacontahepta-2,6,10,14,22,26,30 enyl-)-1, 4-benzoquinone.

[Ubiquinone-9 and ergosterol from Candida paralipolytica yeasts]

Ubiquinone-9 and ergosterol were extracted with hexane from the yeast Candida paralipolytica after hydrolysis with KOH in EtOH with the yield 0.026 and 0.14%, respectively. Ubiquinone-9 was purified by chromatography and recrystallization from absolute alcohol.

Separation of some neutral lipids by normal-phase high-performance liquid chromatography on a cyanopropyl column: ubiquinone, dolichol, and cholesterol levels in sheep liver

The normal-phase high-performance liquid chromatographic separation of neutral lipids into molecular classes was carried out on a cyanopropyl (CN) column eluted with isopropanol in hexane. Cholesteryl, retinyl, and dolichyl esters, triglycerides and vitamin E, ubiquinone, dolichol, phytol, and cholesterol eluted as separate peaks with 0.05% isopropanol in hexane. Cholesterol, retinol, diglyceride, and monoglyceride eluted as separate peaks with 0.75% isopropanol in hexane. These separations could not be achieved on a silica gel column. The method was used to assay sheep liver ubiquinone, dolichol, and cholesterol levels, that were determined as 77, 108 and 1864 micrograms/g wet wt, respectively.

Supercritical fluid chromatography

Chromatographic separations with a supercritical fluid as the mobile phase were suggested more than 20 years ago. Availability of commercial hardware makes this technique more widely usable today. Many separations by this method are now carried out with supercritical carbon dioxide as the mobile phase and packed liquid-chromatography columns as the stationary phase. Although carbon dioxide has many practical advantages, including its near-ambient critical temperature and minimal interference with spectrometric detection, the use of other supercritical fluids or addition of modifiers to carbon dioxide may extend the applications of this technique. Some mixtures that are difficult to analyze by other chromatographic methods may be susceptible to separation by supercritical fluid chromatography. Mixtures that have been separated with supercritical carbon dioxide include resin acids with the empirical formula C20H30O2 and ubiquinones from bacterial cell wall extracts of Legionella pneumophila.

Separation of bacterial ubiquinones by reverse-phase high-pressure liquid chromatography

A procedure was developed for the separation of ubiquinones by high-pressure liquid chromatography on a reverse-phase C18 column. Ubiquinones Q6 through Q14 were resolved in 20 min and were distinguished from menaquinones by comparing UV spectra at 248 and 275 nm.

Fluorescence probe studies of the distribution of ubiquinone homologues in bilayers of dipalmitoylglycerophosphocholine

Fluorescent probes have been used to examine the effect of ubiquinones with varying polyisoprenoid chain lengths varying from 3-10 units on the thermotropic properties of dipalmitoylglycerophosphocholine bilayers. The quenching of fluorescence from n-(9-anthroyloxy) fatty acids (n = 9 or 12 for stearates; n = 16 for palmitate) added to the dispersion by the benzoquinone substituent of ubiquinone was also used as a method of establishing the mode of interaction of the different homologues with the bilayer structure. Fluorescent intensity and polarisation values showed that ubiquinone homologues with polyisoprenoid substituents shorter than six units tended to perturb the thermotropic properties of hydrocarbon domain whereas longer-chain homologues were without effect when present in proportions of up to about 5 mol%. The short-chain homologues also caused extensive fluorescence quenching of the probes suggesting that they were accessible to the interior hydrocarbon domain of the structure and tended to be more concentrated in this region at temperatures above compared to those below the gel-liquid crystalline phase transition of the phospholipid. Ubiquinones with polyisoprenoid chains longer than 6-7 units did not cause fluorescence quenching of the n-(9-anthroyloxy) fatty acid probes either in gel or liquid crystalline bilayers. Addition of the detergent, Triton X-100, to phospholipid dispersions induced fluorescence quenching by long-chain homologues. Ubiquinone-10 was also found to quench fluorescence of diphenylhexatriene, a probe accessible to all of the hydrocarbon domain of the dispersion. The results suggest that the long-chain homologues of ubiquinone are located within bilayer dispersions of phospholipid in a region not sensed by the fatty acid probes or that the bilayer structure prevents the mutual orientations of the fluorophore and the benzoquinone substituent required for formation of a quenching complex.

Nonpolar lipid methylation-identification of nonpolar methylated products synthesized by rat basophilic leukemia cells, retina and parotid

Incorporation of radioactivity from [3H- or 14C-methyl] methionine into nonpolar lipids had been investigated in rat basophilic leukemia (RBL) cells, retina, and rat parotid gland. These nonpolar methylated lipids were extracted into heptane and characterized by thin-layer chromatography, high performance liquid chromatography, gas chromatography, and mass spectrometry. The major methylated nonpolar lipid product in the RBL cells themselves was ubiquinone-9, which accounted for about 90% of the nonpolar lipid and 20-30% of the total radioactive lipid formed. There was a modest increase in the methylation of nonpolar lipids upon stimulation of the RBL cells with IgE and anti-IgE, but the significance of this change is uncertain. In contrast to whole cells, RBL membrane fractions (incubated with [3H-methyl]-S-adenosylmethionine) incorporated radioactivity primarily into fatty acid methyl esters and not ubiquinone. A third product, 2-(methylthio)-benzothiazole, was formed by RBL cells, retina and minced parotid upon incubation in enriched media. This product was formed enzymatically, apparently by the known enzyme S-thiolmethyltransferase, using the thiol substrate which contaminates these media. Evidence suggest that the enzyme may reside, at least in part, on the surface of the cells.