Preparation of dehydrated powder of hemoglobin vesicles

The carbonyl hemoglobin (CO-Hb), which was used to prevent denaturation (metHb) during the preparation of samples, was encapsulated into lipid vesicles constituted from unsaturated phospholipid, cholesterol and unsaturated fatty acid. Unsaturated components were polymerized by γ-irradiation to enhance the stability of bilayer membrane. An aqueous dispersion of resulting Hb vesicles was freeze-dried in the presence of saccharides (50–200 mM) to obtain a dehydrated powder of Hb vesicles. Change in the vesicle size, the leakage of encapsulated Hb and the oxidation of Hb to metHb were not observed. Therefore, the long-term storage of Hb vesicles can be realized as a dry powder.     

Interaction of organic dyes and proteins-determination of the binding constants spectrophotometrically

Summary The spectral change of a small molecule (S) induced by addition of a large molecule (P) was examined theoretically and experimentally, assuming that the interaction betweenS andP follows theLangmuir adsorption isotherm. It was found that intermolecular binding constants could be determined accurately and conveniently by extrapolation to zero of two simple graphic relations, namely, the observed molar extinction coefficient ofS in the presence ofP versus the ratio of (the concentration ofS/the concentration ofP), and of the former versus the reciprocal value of the latter. This spectrophotometric method was applied to the binding of bovine serum albumin and Ponceau3 R and of bovine serum albumin and HABA at p_H 7.0. The results obtained by this method were comparable with those obtained by equilibrium dialysis or by conventional spectrophotometric method.

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Zusammenfassung Unter der Annahme, daß dieLangmuirsche Absorptionsisotherme auch bei der Assoziation hoch-(HMV) und niedermolekularer Verbindungen (NMV) gilt, wurden die Bindungskonstanten bestimmt. Es wurden die spektralen Änderungen in der UV-Absorption der NMV bei Zusatz verschiedener HMV-Mengen gemessen. Die Bindungskonstanten lassen sich durch Kombination zweier graphischer Darstellungen exakt und einfach bestimmen: erstens aus der Beziehung zwischen dem molaren Extinktionskoeffizienten der NMV in Anwesenheit verschiedener HMV-Konzentrationen und dem Konzentrationsverhältnis von NMV zu HMV und zweitens aus dem Zusammenhang der molaren Extinktionskoeffizienten mit den reziproken Werten des oben genannten Konzentrationsverhältnisses. Mit dieser neuen Methode wurden die Bindungskonstanten bei p_h 7.0 von Rinderserumalbumin und Ponceau 3 R bzw. HABA berechnet und mit den durch andere Methoden bestimmten Konstanten verglichen. Die Werte stimmen mit denen aus der Dialysemethode und aus der üblichen spektralphotometrischen Methode überein.

     

Production of highly specific anti-testosterone antiserum by an immunotolerance method

Anti-testosterone antisera were produced by pretreatment of rabbits with 15 alpha-carboxymethyl-5 alpha-dihydrotestosterone linked to a copolymer of D-glutamic acid and D-lysine (D-GL) before immunization with the bovine serum albumin conjugate of 15 alpha- and 15 beta-carboxymethyltestosterone. The specificity for 5 alpha-dihydrotestosterone of the antitestosterone antisera was considerably improved.     

Mononuclear five-coordinate molybdenum(IV) and -(V) monosulfide complexes coordinated with dithiolene ligands: reversible redox of Mo(V)/Mo(IV) and irreversible dimerization of [MoVS]- cores to a dinuclear [MoV2(mu-S)2]2- Core

A mononuclear five-coordinate molybdenum(IV) monosulfide complex, (Et4N)2[MoS(L)2] (L = cyclohexene-1,2-dithiolate) (1), was obtained and characterized by IR, UV-vis spectroscopic methods, and X-ray crystallography. 1 was oxidized by an equivalent ferrocenium cation to give the corresponding mononuclear molybdenum(V) complex, (Et4N)[MoS(L)2] (2), which was stable for a few minutes under a lower concentration than 0.3 mM and then further dimerized to (Et4N)2[Mo(L)2]2(mu-S)2 (3).     

Determination of 4-alkylphenols by novel derivatization and gas chromatography-mass spectrometry

A simple and sensitive method for the determination of alkylphenols in water samples has been developed using gas chromatography-mass spectrometry. Alkylphenols were determined after the extractive derivatization with pentafluoropyridine. The derivatization of alkylphenols efficiently proceeded to give the corresponding 4-tetrafluoropyridyl derivatives under the biphasic reaction system. The derivatization conditions including the phase-transfer catalyst, the amount of pentafluoropyridine, the reaction time, the concentration of NaOH and organic solvent were optimized. On the mass spectra of these derivatives, intense specific ion peaks were observed: m/z 256 for 4-n-alkylphenols and m/z 284 for 4-tert.-alkylphenols. Calibration curves were linear in the range of 20-1000 ng/l (200-10,000 ng/l for nonylphenol), and the detection limits varied between 6.93 and 15.7 ng/l (85.2 ng/l for nonylphenol). The average recoveries of the alkylphenols in a fortified river water sample (100 ng/l except for nonylphenol: 1000 ng/l) ranged from 91.1 to 112%. The relative standard deviations were found to be between 5.6 and 16%. This method was successfully applied to the determination of alkylphenols in river water.     

Chemoenzymatic synthesis of (+)-totarol, (+)-podototarin, (+)-sempervirol, and (+)-jolkinolides E and D

The enzymatic resolution products [(1R,4aR,8aR)-1,2,3,4,4a,5,6,7,8,8a-decahydro-5,5,8a-trimethyl-2-oxo-trans-naphthalene-1-methanol-2-ethylene acetal (8aR)-7 (98% ee) and {acetate of (1S,4aS,8aS)-1,2,3,4,4a,5,6,7,8,8a-decahydro-5,5,8a-trimethyl-2-oxo-trans-naphthalene-1-methanol-2-ethylene acetal} (8aS)-9 (>99% ee)] obtained by the lipase-catalyzed enantioselective acetylation of (±)-7 in the presence of vinyl acetate as an acyl donor were converted to the ,β-unsaturated ketones (8aR)-6 and (8aS)-6, respectively. Concise syntheses of (+)-totarol 1, (+)-podototarin 2 and (+)-sempervirol 3 were achieved based on Michael reactions between (8aS)-6 and the appropriate β-keto ester followed by aldol condensation. The first chiral syntheses of (+)-jolkinolides E 4 and D 5 were achieved from (5R,10R,12R)-12-hydroxypodocarpa-8(14)-en-13-one 15 derived from (8aR)-6.     

Reactivities of Stable Rotamers: XLIV. Ring-Opening Reactions of 1-(9-Fluorenyl)-2-(2-methyl-2-oxiranyl)naphthalene Rotamers With Acids and the Structure of Oxiranes

X-ray crystallography of the ap-form of the 1-(9-fluorenyl)-2-(2-methyl-2-oxiranyl)naphthalene has revealed that the carbon atom of the oxirane which is connected to the naphthyl group in this compound is almost planar. The specific structural features of the epoxy ring in this compound are caused by sterical effects and by the presence of a -system in the immediate vicinity of the oxirane ring. Certain differences have been found also in reactivity of rotational isomers of 2-X-substituted 1-[1-(9-fluorenyl)-2-naphthyl]ethyl cations (X = O, S, Se). At X = O arose more deprotonation product from the -position of the oxygen than in reactions of sulfur and selenium-containing analogs. Reactions of epoxides with zinc chloride almost exclusively gave the corresponding aldehydes.     

A GaCl3-catalyzed [4+1] cycloaddition of alpha,beta-unsaturated carbonyl compounds and isocyanides leading to unsaturated gamma-lactone derivatives

A GaCl3-catalyzed reaction of alpha,beta-unsaturated ketones with isocyanides leading to the formation of unsaturated lactone derivatives is described. This is the first example of the catalytic [4+1] cycloaddition of alpha,beta-unsaturated ketones and isocyanides. GaCl3 is an excellent catalyst due to its lower oxophilicity, which is desirable for all of the key steps, such as E/Z isomerization, cyclization, and deattachment from the products.     

Preparation of polymers with substituted allyl end group using dimer of α-methylvinyl monomer as addition fragmentation chain transfer agent at high temperatures

The dimerization of methyl methacrylate, ethyl methacrylate, methacrylonitrile, and α-methylstyrene to 2-substituted-1-allylic compounds [CH₂?C(X)CH₂C(CH₃)₂X] (X = COOR, C₆H₅, or CN), and methyl α-ethylacrylate to a 3-substituted-2-allylic compound [CH₃CH?C(COOCH₃)CH₂C(CH₃)(C₂H₅) COOCH₃] was carried out by catalytic chain transfer using benzylbis (dimethylglyoximato) (pyridine) cobalt (III). These dimers were then used as addition-fragmentation chain transfer agents in the polymerizations of methyl methacrylate and styrene at 80⁰C or above. Cross-dimers from methacrylic ester-α-methylstyrene and methacrylonitrile-α-methylstyrene mixtures were similarly prepared. Except for those from methyl α-ethylacrylate and methacrylonitrile, all the dimers participated in the addition-fragmentation and the copolymerization to different extents. The dimer of methyl α-ethylacrylate was actually inactive during the styrene and methyl methacrylate polymerizations. The methacrylonitrile dimer was primarily incorporated in the polymer chain through copolymerization. Among the dimer and the cross-dimers from α-methylstyrene with the other monomers, those bearing the α-methylstyrene moiety in the α-substituent [CH₂?C(X)CH₂C(CH₃)₂C₆H₅, X?COOCH₃, COOC₂H₅, and CN] are noted as highly reactive chain transfer agents. © 1994 John Wiley & Sons, Inc.     

Isolation,Diversity and Characterization of Ulvan-Degrading Bacteria Isolated from Marine Environments

In this study, we aimed to isolate bacteria capable of degrading the polysaccharide ulvan from the green algae Ulva sp. (Chlorophyta, Ulvales, Ulvaceae) in marine environments. We isolated 13 ulvan-degrading bacteria and observed high diversity at the genus level. Further, the genera Paraglaciecola, Vibrio, Echinicola, and Algibacter, which can degrade ulvan, were successfully isolated for the first time from marine environments. Among the 13 isolates, only one isolate (Echinicola sp.) showed the ability not only to produce externally expressed ulvan lyase, but also to be periplasmic or on the cell surface. From the results of the full-genome analysis, lyase was presumed to be a member of the PL25 (BNR4) family of ulvan lyases, and the bacterium also contained the sequence for glycoside hydrolase (GH43, GH78 and GH88), which is characteristic of other ulvan-degrading bacteria. Notably, this bacterium has a unique ulvan lyase gene not previously reported.