Analysis of sugar phosphates in plants by ion chromatography on a titanium dioxide column with pulsed amperometric detection

This paper describes the development of a practical method for the analysis of sugar phosphates from the model higher plant Arabidopsis thaliana by high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The extraction method of sugar phosphates from higher plants was first optimized for HPAEC-PAD analysis. In order to improve the resolution in HPAEC-PAD, a column packed with titanium dioxide resin was used. The titanium dioxide column was used as a trap-column for sugar phosphates and nucleotides, for the removal of sample matrices. Sample pretreatment was achieved in-line and automatically using a six-port valve placed after the injection valve.     

Photochemical generation of cyclopentadienyliron dicarbonyl anion by a nicotinamide adenine dinucleotide dimer analogue

Irradiation of the absorption band of an NAD (nicotinamide adenine dinucleotide) dimer analogue, 1-benzyl-1,4-dihydronicotinamide dimer, (BNA)(2), in acetonitrile containing a cyclopentadienyliron dicarbonyl dimer, [CpFe(CO)(2)](2), results in generation of 2 equiv of the cyclopentadienyliron dicarbonyl anion, [CpFe(CO)(2)](-), accompanied by the oxidation of (BNA)(2) to yield 2 equiv of BNA(+). The studies on the quantum yields, the electrochemistry, and the transient absorption spectra have revealed that the photochemical generation of [CpFe(CO)(2)](-) by (BNA)(2) proceeds via photoinduced electron transfer from the triplet excited state of (BNA)(2) to [CpFe(CO)(2)](2).     

High dispersion and fluorescence of anthracene doped in polyphenylsiloxane films

Phenylsilsesquioxane-diphenylsiloxane glass thick films doped with anthracene were prepared from homogeneous coating sols obtained from two different approaches. One approach consisted in incorporating the dye during the glass preparation (which implies the incorporation of the dye in an aqueous media). The doped-glass was further dissolved in the solvents mixture composed of cyclohexane and acetone. The other approach which is non-aqueous consisted simply in dissolving directly the preformed non-doped polyphenylsiloxane glass in the dye solutions. The stability of the organic-inorganic hybrid glass matrix in most organic solvents makes possible the incorporation of the dye without problems of miscibility and dispersion in the hybrid matrix. The coating was performed at room temperature using spin-coating technique prior to further heat-treatment. Crack-free and homogeneous films of high optical quality were obtained. The optical properties of the doped films based on their absorption and emission spectra were discussed owing the incorporation route of the dye. The results showed that the non-aqueous approach used to incorporate the dye minimizes the dye aggregation. This property associated to the preparation route permits to obtain optically active hybrid films loaded with high concentrations of anthracene (in the order of 10⁻² M) which enhance the fluorescence of the doped films. The hybrid doped-films obtained represent therefore a tremendous potential for applications in the field of optics and photonics including the development of new nonlinear optical materials. Bouzid Menaa and Masahide Takahashi both the author contributed equally.     

A new route to 2-amino- or 2-hydroxy-3-pyridinecarboxylic acid derivatives

Schiff's bases derived from ketones and t-butylamine ( 1 ) reacted with methyl methoxymethylenemalonate to give 2-hydroxy-3-pyridinecarboxylates. Similarly, treatment of 1 with ethoxymethylenemalononitrile gave 2-amino-3-pyridinecarbonitriles. Compounds 1 on reaction with ethyl 2-cyano-3-ethoxypropenoate afforded 2-amino-3-pyridinecarboxylates.     

Steric-control for the enantioselective hydrolysis of amino acid esters in hybrid membrane systems

The enantioselective hydrolysis of the amino acid esters, p-nitrophenyl-N-dodecanoyl-D(L)-phenylalaninates (C(12)-D(L)-Phe-PNP) catalyzed by active tripeptide, N-(benzyloxycarbonyl)-L-phenylalanyl-L-histidyl-L-leucine (Z-PheHisLeu) in the presence of coaggregates (hybrid membranes) composed of native phospholipid, L-alpha-dimyristoylphosphatidylcholine (DMPC) and nonionic surfactant, polyoxyethylene (8) lauryl ether (C(12)(EO)(8)) was easily controlled by regulating the reaction temperature and changing the composition of coaggregates. Furthermore, excellent correlations were observed between the enantioselectivity in the hydrolysis of C(12)-D(L)-Phe-PNP catalyzed by Z-PheHisLeu in the presence of coaggregates and physical properties of hybrid membranes. It is assumed that catalytic activities of tripeptide catalyst in hybrid membranes should be regulated by changing the microenvironments of reaction fields.     

Hereditary subtypic patterns detected in the Ba fragment of complement factor B: occurrence of four common alleles in Japanese

A procedure which can detect subtype-specific minor bands of factor B (BF) by polyacrylamide gel isoelectric focusing is presented. After zymosan-mediated fragmentation of BF in serum via alternative pathway for complement activation, serum samples are subjected to isoelectric focusing in a narrow pH range (4.2-4.9). The Ba fragments are detected by using immunoblotting. In addition to the previously reported minor bands with subtypic specificities, heterogeneities are observed in other minor band group, where a single minor band corresponds exclusively to a subtype in a regular combination with the previously announced subtypic patterns. A one-to-one correspondence of a single band to each subtype provides an unambiguous determination for three subtypic phenotypes deduced from the two divided BF*F alleles, BF*FA and BF*FB. An autosomal codominant heredity is confirmed through segregation analysis. A population survey reveals that four common alleles, BF*S, BF*FA, BF*FB, BF*Fb1, occur in a Japanese population and the former three alleles, except BF*Fb1, occur in a Cambodian population. The presence or absence of a single anodal minor band was found to be the only difference after neuraminidase treatment of FA and FB, implying that an amino acid substitution responsible for the FA-FB subtypic difference is involved in an additional acquisition in FA of an oligosaccharide unit with a charged sialic acid.