Esterification of side-chain oxysterols by lysosomal phospholipase A2.

Side-chain oxysterols produced from cholesterol either enzymatically or non-enzymatically show various bioactivities. Lecithin-cholesterol acyltransferase (LCAT) esterifies the C3-hydroxyl group of these sterols as well as cholesterol. Lysosomal phospholipase A2 (LPLA2) is related to LCAT but does not catalyze esterification of cholesterol.

Isolation of lactic acid bacteria capable of reducing environmental alkyl and fatty acid hydroperoxides, and the effect of their oral administration on oxidative-stressed nematodes and rats.

Reinforcement of the hydroperoxide-eliminating activity in the small and large intestines should prevent associated diseases. We previously isolated a lactic acid bacterium, Pediococcus pentosaceus Be1 that facilitates a 2-electron reduction of hydrogen peroxide to water. In this study, we successfully isolated an alternative lactic acid bacterium, Lactobacillus plantarum P1-2, that can efficiently reduce environmental alkyl hydroperoxides and fatty acid hydroperoxides to their corresponding hydroxyl derivatives through a 2-electron reduction.

Comparison of composition-gradient sedimentation equilibrium and composition-gradient static light scattering as techniques for quantitative characterization of biomolecular interactions: A case study.

The equilibrium hetero-association of NADH oxidase and peroxiredoxin was characterized by means of independently conducted measurements of composition-gradient sedimentation equilibrium and composition-gradient static light scattering. Results obtained from both experiments were quantitatively accounted for by a model according to which a dimer of NADH oxidase forms a 1:1 equilibrium complex with a decamer of peroxiredoxin under the conditions of these experiments. The best-fit equilibrium constants for heteroassociation of the two proteins obtained from the two measurements were found to be identical to well within the uncertainty of estimate of each of the two methods.

Free flavins accelerate release of ferrous iron from iron storage proteins by both free flavin-dependent and -independent ferric reductases in Escherichia coli.

Ferredoxin NADP oxidoreductase (Fpr) and oxygen-insensitive NAD(P)H nitroreductase (NfnB) are purified from Escherichia coli JM109 (E. coli JM109) as a predominant free flavin-independent ferric reductase. In the present study, we prepared natural iron storage proteins, E.

Purified thioredoxin reductase from O-sensitive Bifidobacterium bifidum degrades HO by interacting with alkyl hydroperoxide reductase.

Bifidobacterium is beneficial for host health and exhibits different O sensitivity levels among species or strains via unknown mechanisms. Bifidobacterium bifidum JCM1255, a type species of Bifidobacterium, is an O-sensitive bacterium that can grow under low-O (5%) conditions, and the growth of this species is inhibited under high-O conditions (10% ∼) with accumulation of HO. We previously reported that NADH or NAD(P)H oxidase-active fractions were detected during purification using microaerobically grown B.

O-inducible HO-forming NADPH oxidase is responsible for the hyper O sensitivity of Bifidobacterium longum subsp. infantis.

Bifidobacteria are beneficial anaerobes, and their O sensitivity levels differ among species as a function of unknown molecular mechanisms. Bifidobacterium longum subspecies infantis (B. infantis), a predominant colonizer of the gastrointestinal tract of infants, showed a hyper O-sensitive growth profile with accompanying a production of HO.

Intracellular free flavin and its associated enzymes participate in oxygen and iron metabolism in lacking a respiratory chain.

is a recently identified bacterium which grows well under both aerobic and anaerobic conditions and may prove useful for biomass utilization. despite lacking a respiratory chain, consumes oxygen at a similar rate to (130-140 μmol oxygen·min·g dry cells at 37 °C), suggesting that it has an alternative system that uses a large amount of oxygen. NADH oxidase (Nox) was previously reported to rapidly reduce molecular oxygen content in the presence of exogenously added free flavin.

Isolation of lactic acid bacteria exhibiting high scavenging activity for environmental hydrogen peroxide from fermented foods and its two scavenging enzymes for hydrogen peroxide.

To obtain lactic acid bacteria that scavenge environmental hydrogen peroxide, we developed a specialized enrichment medium and successfully isolated Pediococcus pentosaceus Be1 strain from a fermented food. This strain showed vigorous environmental hydrogen peroxide scavenging activity over a wide range of hydrogen peroxide concentrations. High Mn-catalase and NADH peroxidase activities were found in the cell-free extract of the P.

Cucumis sativus secretes 4'-ketoriboflavin under iron-deficient conditions.

A new compound in cucumber, Cucumis sativus, nutrient solution that appears under iron-deficient conditions, but not under ordinary culture conditions, has been revealed by HPLC analysis. The chemical structure of this compound was identified using LC-MS and NMR techniques as that of 4'-ketoriboflavin. This is the first report to show that 4'-ketoriboflavin can be found in metabolites from organisms.

Adaptive response of Amphibacillus xylanus to normal aerobic and forced oxidative stress conditions.

Amphibacillus xylanus grows at the same rate and with the same cell yield under aerobic and anaerobic conditions. Under aerobic conditions, it exhibits vigorous oxygen consumption in spite of lacking a respiratory system and haem catalase. To understand the adaptive response of A.

Purification and characterization of oxygen-inducible haem catalase from oxygen-tolerant Bifidobacterium asteroides.

Bifidobacterium asteroides, originally isolated from honeybee intestine, was found to grow under 20% O(2) conditions in liquid shaking culture using MRS broth. Catalase activity was detected only in cells that were exposed to O(2) and grown in medium containing a haem source, and these cells showed higher viability on exposure to H(2)O(2). Passage through multiple column chromatography steps enabled purification of the active protein, which was identified as a homologue of haem catalase on the basis of its N-terminal sequence.

Chloroplast NADPH-dependent thioredoxin reductase from Chlorella vulgaris alleviates environmental stresses in yeast together with 2-Cys peroxiredoxin.

Chloroplast NADPH-dependent thioredoxin reductase (NTRC) catalyzes the reduction of 2-Cys peroxiredoxin (2-Cys Prx) and, thus, probably functions as an antioxidant system. The functions of the enzyme in oxidative and salt stresses have been reported previously. We have previously identified and characterized NTRC in Chlorella vulgaris.

Is novel signal transducer sulfur oxide involved in the redox cycle of persulfide at the catalytic site cysteine in a stable reaction intermediate of mercaptopyruvate sulfurtransferase?

Abstract In transsulfuration reaction catalyzed by rat mercaptopyruvate sulfurtransferase (MST), a stable persulfide is formed at the catalytic site cysteine Cys(247) as a reaction intermediate. The outer sulfur atom is donated by the substrate, thiosulfate, or by mercaptopyruvate. MST serves as a thioredoxin-dependent antioxidant possessing self-regulated enzymatic activity.

Synechocystis ferredoxin-NADP(+) oxidoreductase is capable of functioning as ferric reductase and of driving the Fenton reaction in the absence or presence of free flavin.

We purified free flavin-independent NADPH oxidoreductase from Synechocystis sp. PCC6803 based on NADPH oxidation activity elicited during reduction of t-butyl hydroperoxide in the presence of Fe(III)-EDTA. The N-terminal sequencing of the purified enzyme revealed it to be ferredoxin-NADP(+) oxidoreductase (FNR( S )).

Lactobacillus ozensis sp. nov., isolated from mountain flowers.

Five strains (Mizu2-1(T), Gon2-7, Koba6-1, Koyu2-2 and Miya2-2) of lactic acid bacteria (LAB) were isolated from flowers in Oze National Park, Japan, using anaerobic cultivation. The five isolates were found to share identical 16S rRNA gene sequences. The isolates exhibited low levels of 16S rRNA gene sequence similarity to known LAB; the closest recognized relatives of strain Mizu2-1(T) were the type strains of Lactobacillus kunkeei (94.

Lactobacillus floricola sp. nov., lactic acid bacteria isolated from mountain flowers.

Five strains (Ryu1-2(T), Gon2-9, Ryu4-3, Nog8-1 and Aza1-1) of lactic acid bacteria were isolated from flowers in mountainous areas in Japan, Oze National Park, Iizuna mountain and the Nikko area. The five isolates were found to share almost identical (99.6-100 % similar) 16S rRNA gene sequences and were therefore deemed to belong to the same species.

Chlorella vulgaris aldehyde reductase is capable of functioning as ferric reductase and of driving the fenton reaction in the presence of free flavin.

The free flavin-dependent Fenton reaction was detected in cell-free extracts of Chlorella. The corresponding enzyme was purified to homogeneity, and its N-terminal sequence was highly homologous to those of aldo-keto reductase family enzymes. The purified enzyme displayed aldehyde reductase activity in the presence of NADPH.

Escherichia coli ferredoxin-NADP+ reductase and oxygen-insensitive nitroreductase are capable of functioning as ferric reductase and of driving the Fenton reaction.

Two free flavin-independent enzymes were purified by detecting the NAD(P)H oxidation in the presence of Fe(III)-EDTA and t-butyl hydroperoxide from E. coli. The enzyme that requires NADH or NADPH as an electron donor was a 28 kDa protein, and N-terminal sequencing revealed it to be oxygen-insensitive nitroreductase (NfnB).

Crystallization and preliminary X-ray analysis of NADH:rubredoxin oxidoreductase from Clostridium acetobutylicum.

NADH:rubredoxin oxidoreductase (NROR), an O(2)-inducible protein, is a versatile electron donor for scavengers of O(2) and reactive oxygen species (ROS) in Clostridium acetobutylicum. Recombinant NROR was overexpressed in Escherichia coli and purified to homogeneity; it was subsequently crystallized using the sitting-drop vapour-diffusion method at 293 K. Preliminary crystallographic analysis revealed that the crystals belonged to space group P4(1)22 or P4(3)22, with unit-cell parameters a = b = 98.

Structure analysis of the flavoredoxin from Desulfovibrio vulgaris Miyazaki F reveals key residues that discriminate the functions and properties of the flavin reductase family.

The crystal structure of flavoredoxin from Desulfovibrio vulgaris Miyazaki F was determined at 1.05 A resolution and its ferric reductase activity was examined. The aim was to elucidate whether flavoredoxin has structural similarity to ferric reductase and ferric reductase activity, based on the sequence similarity to ferric reductase from Archaeoglobus fulgidus.

Taxonomical and physiological comparisons of the three species of the genus Amphibacillus.

Amphibacillus is a genus for Gram-positive, spore-forming, rod-shaped, facultatively anaerobic bacteria with low-G+C content of DNA, established by Niimura et al. in 1990. Amphibacillus xylanus, the type species of the genus, grows well under both strictly anaerobic and aerobic conditions in spite of lacking any isoprenoid quinones, cytochromes, and catalase.

Expression pattern of a chloroplast NADPH-dependent thioredoxin reductase in Chlorella vulgaris during hardening and its interaction with 2-Cys peroxiredoxin.

A chloroplastic NADPH-dependent thioredoxin reductase gene was identified from Chlorella vulgaris and designated CvNTRC. Mature CvNTRC protein (mCvNTRC) was expressed in Escherichia coli, and it showed both NADPH-dependent thioredoxin reductase (NTR) and thioredoxin (Trx)-like dithiol-disulfide oxidoreductase activities. The transcript of CvNTRC increased throughout 24-h hardening, whereas the encoded protein amount and total NTR activity decreased once and then increased during hardening.

O2 and reactive oxygen species detoxification complex, composed of O2-responsive NADH:rubredoxin oxidoreductase-flavoprotein A2-desulfoferrodoxin operon enzymes, rubperoxin, and rubredoxin, in Clostridium acetobutylicum.

Clostridium acetobutylicum, an obligate anaerobe, grows normally under continuous-O(2)-flow culture conditions, where the cells consume O(2) proficiently. An O(2)-responsive NADH:rubredoxin oxidoreductase operon composed of three genes (nror, fprA2, and dsr), encoding NROR, functionally uncharacterized flavoprotein A2 (FprA2), and the predicted superoxide reductase desulfoferrodoxin (Dsr), has been proposed to participate in defense against O(2) stress. To functionally characterize these proteins, native NROR from C.