Determination of idebenone in plasma by HPLC with post-column fluorescence derivatization using 2-cyanoacetamide.

Idebenone is a benzoquinone analog that is used in the treatment of several neurological disorders including Friedreich's ataxia. It was found that the reaction of idebenone with 2-cyanoacetamide under alkaline conditions generates fluorescent products, and the reaction was considered to proceed via Craven's reaction. The reaction mixture from idebenone gave fluorescence with excitation and emission maximum wavelengths at 358 nm and 409 nm, respectively.

Enhancement of the structural stability of full-length clostridial collagenase by calcium ions.

The clostridial collagenases G and H are multidomain proteins. For collagen digestion, the domain arrangement is likely to play an important role in collagen binding and hydrolysis. In this study, the full-length collagenase H protein from Clostridium histolyticum was expressed in Escherichia coli and purified.

The subcellular localization of cyclin B2 is required for bipolar spindle formation during Xenopus oocyte maturation.

Cyclins B1 and B2 are subtypes of cyclin B, a regulatory subunit of a maturation/M-phase promoting factor, and they are also highly conserved in many vertebrate species. Cyclin B1 is essential for mitosis, whereas cyclin B2 is regarded as dispensable. However, the overexpression of the cyclin B2 N-terminus containing the cytoplasmic retention signal, but not cyclin B1, inhibits bipolar spindle formation in Xenopus oocytes and embryos.

Synthetic biotinylated peptide compound, BP21, specifically recognizes lysophosphatidylcholine micelles.

Lysophosphatidylcholine, a major phospholipid component of oxidized low-density lipoprotein, is implicated in many inflammatory diseases, including atherosclerosis. We previously reported that Asp-hemolysin-related synthetic peptide (P21) composed of 21 amino acid residues markedly inhibits the bioactivities of oxidized low-density lipoprotein and lysophosphatidylcholine, by directly binding to oxidized low-density lipoprotein and lysophosphatidylcholine. Here, to clarify whether P21 specifically binds to lysophosphatidylcholine and what forms of lysophosphatidylcholine with which P21 interact, we investigated the interaction between P21 containing two tryptophan residues and lysophosphatidylcholine by using fluorescence spectroscopy, polyacrylamide gel electrophoresis, and surface plasmon resonance.

Synthetic biotinylated peptide compounds derived from Asp-hemolysin: novel potent inhibitors of platelet-activating factor.

Platelet-activating factor (PAF: 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine), a potent inflammatory mediator, is implicated in many inflammatory diseases and may possibly serve as a direct target for anti-inflammatory drugs. We have previously reported that Asp-hemolysin-related synthetic peptides (P4-P29) inhibit the bioactivities of oxidized low-density lipoprotein (ox-LDL) containing PAF-like lipids by direct binding to ox-LDL, which plays a key role in the atherosclerotic inflammatory process. In this study, we investigated whether these peptides inhibit the bioactivities of PAF by binding to PAF and its metabolite/precursor lyso-PAF.

Face or vase? Areal homogeneity effect.

To examine the effect of homogeneity of area in figure-ground organization, we made several variations of Rubin's goblet. Observers were required to judge whether they perceived a goblet or profiles (faces). Our results showed that, when both profiles were the same lightness, the percentage of judgments (goblet vs profiles) were almost equal.

The unique structure of carbonic anhydrase αCA1 from Chlamydomonas reinhardtii.

Chlamydomonas reinhardtii α-type carbonic anhydrase (Cr-αCA1) is a dimeric enzyme that catalyses the interconversion of carbon dioxide and carbonic acid. The precursor form of Cr-αCA1 undergoes post-translational cleavage and N-glycosylation. Comparison of the genomic sequences of precursor Cr-αCA1 and other αCAs shows that Cr-αCA1 contains a different N-terminal sequence and two insertion sequences.

The high mannose-type glycan binding lectin actinohivin: dimerization greatly improves anti-HIV activity.

The actinomycete-derived lectin actinohivin (AH) inhibits entry of HIV-1 to susceptible cells at low nM concentrations. The cooperative binding of three segments of AH to three high mannose-type glycans (HMTGs) of HIV-1 gp120 generates specific and strong anti-HIV activity. Dimerization of AH effectively improves anti-HIV activity by increasing the number of HMTG-binding pockets.

Determination of ubiquinone in blood by high-performance liquid chromatography with post-column fluorescence derivatization using 2-cyanoacetamide.

It was shown that ubiquinone (CoQ(10)) and ubiquinol (CoQ(10)H(2)) produce fluorescence products under alkaline conditions when reacted with 2-cyanoacetamide. The reaction mixture from CoQ(10) gave fluorescence with excitation and emission maximum wavelengths at 442 nm and 549 nm, respectively. This reaction was considered to proceed via Craven's reaction.

Effects of antioxidant polyphenols on TNF-alpha-related diseases.

Oxidative stress and inflammatory responses sustained for a long period of time cause many diseases. A proinflammatory cytokine, tumor necrosis factor α (TNF-α), plays a pivotal role in the pathogenesis of chronic and auto-immune diseases. The present review, supplemented by hitherto unpublished data of the authors and their coworkers, shows that the intake of polyphenols contained in natural sources, such as hydroxytyrosol, tyrosol, oleuropein (olives), naringin and hesperidin (Citrus fruits), resveratrol, procyanidins or oligomeric procyanidin (grapes or grape seed extracts), (-)-epigallocatechin gallate (green tea) and quercetin (grapes, green tea) etc.

Suppression of inflammatory responses after onset of collagen-induced arthritis in mice by oral administration of the Citrus flavanone naringin.

Rheumatoid arthritis (RA) is closely related to the pathogenesis of tumor necrosis factor α in lesions. We investigated the suppressive effects of a Citrus flavanone naringin on inflammatory responses in mice with collagen-induced arthritis (CIA), a mouse model for RA. To investigate potential preventive and therapeutic effects of naringin, mice were given naringin orally three times a week from the second immunization with collagen (day 21) and from day 31, when symptoms of CIA had reached a plateau, respectively.

Insights into the structures of DNA damaged by hydroxyl radical: crystal structures of DNA duplexes containing 5-formyluracil.

Hydroxyl radicals are potent mutagens that attack DNA to form various base and ribose derivatives. One of the major damaged thymine derivatives is 5-formyluracil (fU), which induces pyrimidine transition during replication. In order to establish the structural basis for such mutagenesis, the crystal structures of two kinds of DNA d(CGCGRATfUCGCG) with R = A/G have been determined by X-ray crystallography.

Actinohivin: specific amino acid residues essential for anti-HIV activity.

Actinohivin (AH) is a microbial lectin containing 114 amino acids, which inhibits human immunodeficiency virus (HIV) infection. This effect is brought about by its specific binding to Man-α(1-2)-Man unit(s) of high-mannose type glycan (HMTG) bound to HIV gp120. The recently determined crystal structure of AH suggests that three repeated segments (the residue numbers 1-38, 39-76 and 77-114 for segments 1, 2 and 3, respectively) form three sugar-binding pockets to accommodate Man-α(1-2)-Man units.

Crystallographic study of wild-type carbonic anhydrase alpha CA1 from Chlamydomonas reinhardtii.

Carbonic anhydrases (CAs) are ubiquitously distributed and are grouped into three structurally independent classes (alphaCA, betaCA and gammaCA). Most alphaCA enzymes are monomeric, but alphaCA1 from Chlamydomonas reinhardtii is a dimer that is uniquely stabilized by disulfide bonds. In addition, during maturation an internal peptide of 35 residues is removed and three asparagine residues are glycosylated.

Cholesterol-binding toxins and anti-cholesterol antibodies as structural probes for cholesterol localization.

Cholesterol is one of the major constituents of mammalian cell membranes. It plays an indispensable role in regulating the structure and function of cell membranes and affects the pathology of various diseases. In recent decades much attention has been paid to the existence of membrane microdomains, generally termed lipid "rafts", and cholesterol, along with sphingolipids, is thought to play a critical role in raft structural organization and function.

Leuconicines A-G and (-)-eburnamaline, biologically active strychnan and eburnan alkaloids from Leuconotis.

Seven new indole alkaloids of the Strychnos type, leuconicines A-G (1-7), and a new eburnan alkaloid, (-)-eburnamaline (8), were isolated from the stem-bark extract of two Malayan Leuconotis species. The structures of these alkaloids were established using NMR and MS analysis and in the case of 8 also by partial synthesis. Alkaloids 1-5 reversed multidrug resistance in vincristine-resistant KB cells.

An oviposition stimulant binding protein in a butterfly: Immunohistochemical localization and electrophysiological responses to plant compounds.

Oviposition is evoked by plant compounds, which are recognized by chemoreceptive organs of insects. The swallowtail butterfly, Atrophaneura alcinous, oviposits its eggs on the host plant, Aristolochia debilis, in the presence of only two stimulating compounds: an alkaloid, aristolochic acid, and a monosaccharide, sequoyitol. In our previous study, a unique protein of 23 kDa [Oviposition stimulant(s) binding protein (OSBP)] was found in the forelegs of female, but not male A.

Mechanism by which the lectin actinohivin blocks HIV infection of target cells.

Various lectins have attracted attention as potential microbicides to prevent HIV transmission. Their capacity to bind glycoproteins has been suggested as a means to block HIV binding and entry into susceptible cells. The previously undescribed lectin actinohivin (AH), isolated by us from an actinomycete, exhibits potent in vitro anti-HIV activity by binding to high-mannose (Man) type glycans (HMTGs) of gp120, an envelope glycoprotein of HIV.

The generation of lucigenin chemiluminescence from the reaction of guanidino compounds with phenylglyoxal under alkaline conditions and its application.

It is shown that o-carboxyphenylglyoxal, which is converted from ninhydrin by alkali, produces a chemiluminescent lucigenin reaction under alkaline conditions when with reacted with guanidino compounds. It is also demonstrated that phenylglyoxal, which is a model compound of o-carboxyphenylglyoxal, produces a strong chemiluminescent lucigenin reaction under alkaline conditions when reacted with guanidino compounds. Moreover, ESR spectra showed the presence of 5,5-dimethyl-1-pyrroline N-oxide (DMPO)-spin adducts of superoxide anions in a mixture of phenylglyoxal and guanidino compounds under alkaline conditions.

Multiple duplication of the bucentaur gene family, which recruits the APE-like domain of retrotransposon: Identification of a novel homolog and distinct cellular expression.

The p97bcnt/cfdp2 is a ruminant-specific gene created by a combination of gene duplication of ancestral bcnt (bucentaur) or cfdp1 (craniofacial developmental protein 1), bcnt/cfdp1, and the insertion of a retrotransposable element-1 (RTE). As a result, p97Bcnt recruits the whole apurinic/apyrimidinic endonuclease (APE)-like domain of RTE in the middle of the molecule (RTE domain) as a region encoded by an exon. In addition, p97Bcnt contains two intramolecular repeats (IRs) of 40 amino acids each in the C-terminal region, whereas Bcnt/Cfdp1 contains one IR.

[NMR analyses of oligosaccharides from a new water-absorbing polysaccharide produced by the family oxalobacteraceae].

Partial acid hydrolysis of a new water-absorbing polysaccharide (WAP) from the family Oxalobacteraceae gave six di-, four tri-, two tetra-, two penta-, and one hexasaccharides composed of mannose, glucose, and/or galactose. The structures of oligosaccharides 1-15 were elucidated by extensive 2D NMR spectroscopic analyses. (1)H- and (13)C-NMR chemical shift assignments of oligosaccharides 1-14 are presented.

Social rank modulates brain arginine vasotocin immunoreactivity in false clown anemonefish (Amphiprion ocellaris).

The brain nanopeptide arginine vasotocin (AVT) and its mammalian homolog arginine vasopressin are involved in the regulation of social and reproductive behavior. We investigated the relationship between social rank formation and the brain AVT system in the false clown anemonefish (Amphiprion ocellaris), which forms a social rank that leads to sex differentiation in higher-ranked individuals. Tanks of three sexually immature fish were kept for 90 days and each fish's behavior was observed once a month.

Characterization of chemoreceptive protein binding to an oviposition stimulant using a fluorescent micro-binding assay in a butterfly.

A native female-specific chemoreceptive protein of a swallowtail butterfly [oviposition stimulant binding protein (OSBP)] was shown to specifically bind to aristolochic acid, a main stimulant for oviposition from its host plant. Oviposition stimulants are recognized by chemoreceptive organs of insects. OSBP isolated previously from the chemoreceptive organs was assumed to bind to an oviposition stimulant.

Social environment and sex differentiation in the false clown anemonefish, Amphiprion ocellaris.

Plasticity in sex differentiation is known to be common in teleost fishes. Anemonefishes are protandrous; females are the largest and dominant members of social groups, displaying frequent aggressive behavior towards other members of groups. The second-ranked individuals become males and others remain as non-reproductive individuals.