Studies on the chemical modification of monensin. IV. Synthesis, sodium ion permeability, and biological activity of 7-O-acyl- and 7-O-alkylmonensins.

7-O-Acyl-(4a-e) and 7-O-alkylmonensins (5a-d) were prepared from monensin (1). Their lipophilicity, sodium ion permeability in human erythrocytes, antibacterial activity and effect on rat tail artery were examined. There was a correlation between lipophilicity and sodium ion permeability as well as between lipophilicity and antibacterial activity. We also found that the compound having larger sodium ion permeability, showed stronger contraction of rat tail artery. 7-O-Benzylmonensin (5c) exhibited higher lipophilicity and larger sodium ion permeability than monensin (1) among the tested monensin derivatives. In addition, antibacterial activity and contractile effect on rat tail artery of 5c were comparable to those of 1.     

UVB Irradiation Induces Changes in Cellular Localization and Phosphorylation of Mouse HSP27

Abstract— We investigated the induction, cellular localization and phosphorylation of a low-molecular weight stress protein (heat shock protein 27, HSP27) by UVB (290-320 nm, max. 312 nm) irradiation stress using immunoblot and indirect immunofluorescence analysis in in vivo and in vitro experiments. The HSP27 was constitutively expressed and distributed in the cytoplasmic fraction of Pam 212 cells (mouse keratinocyte line) or dorsal skin. The increase in the cytoplasm HSP27 level induced by UVB irradiation was less than two-fold that in nonirra-diated controls. On the other hand, the translocation of HSP27 from cytoplasm to the nucleus or perinuclear area was time- and dose-dependently induced by UVB irradiation. After UVB irradiation, three isoforms having different isoelectric points were detected in nucleic HSP27 by two-dimensional immunoblotting. The most basic isoform was the unphosphorylated type and the two acidic isoforms were phosphorylated, suggesting that HSP27 is phosphorylated in response to UVB irradiation and accumulates in or around the nucleus as a phosphorylated isoform. These results suggest that the translocation and phosphorylation of HSP27 are induced in response to UVB-irradiation stress.     

Reversible crosslinking in cellulose. III. Factors controlling the oxidation behavior of mercapto groups in cotton derivatives

The oxidation behavior of mercaptocellulose prepared from tosylated cotton and of cellulose β-mercaptoethylaminocarboxylate (RDTC), which was prepared by reduction of a cotton derivative made by the reaction with bis-β-isocyanatoethyl disulfide, was studied, and the factors controlling the oxidation behaviors of solid polymeric mercaptans were discussed. RDTC was converted quantitatively to the corresponding disulfide by oxidation under mild conditions. Repeated oxidation–reduction cycles were applied to RDTC to demonstrate complete reversibility of disulfide crosslinking. On the other hand, only a portion of the mercaptan in mercaptocellulose could form disulfide by oxidation. It is considered that the mobility of the mercapto groups necessary for the oxidation coupling is restricted because they are attached directly to rigid cellulose chains. The oxidation of RDTC with air in alkaline medium was studied kinetically. It was found that the oxidation of the mercaptan in paired placement in the cellulose matrix proceeded more than ten times faster than that of the randomly placed mercaptan.     

Glycosides of Atractylodes lancea

Five sesquiterpenoid glycosides (two guaiane-type glycosides and three eudesmane-type glucosides) and a glucoside of an acetylene derivative were newly isolated from the water-soluble portion of the methanolic extract of Atractylodes lancea rhizome together with 26 known compounds. Their structures were characterized as atractyloside A 14-O-beta-D-fructofuranoside, (1S,4S,5S,7R,10S)-10,11,14-trihydroxyguai-3-one 11-O-beta-D-glucopyranoside, (5R,7R,10S)-isopterocarpolone beta-D-glucopyranoside, cis-atractyloside I, (2R,3R,5R,7R,10S)-atractyloside G 2-O-beta-D-glucopyranoside, and (2E,8E)-2,8-decadiene-4,6-diyne-1,10-diol 1-O-beta-D-glucopyranoside on the basis of chemical and spectroscopic investigation. The presence of six characteristic guaiane-type glucosides in both rhizomes of A. lancea and Atractylodes japonica suggested a close chemotaxonomic relationship between them.     

Measurement of pork freshness using potentiometric sensor

This study evaluated pork freshness using potentiometric solid-state electrodes in order to detect chemical indices such as reduced compounds, organic compounds and sulfides, which are produced during the initial stage of putrefaction in meat. Pt, CuS and Ag₂S electrodes selected as solid-state electrodes have, respectively, been used to detect the organic compounds (regarded as chemical indices of deterioration in meat freshness). The outputs of these electrodes have been analyzed by principal component analysis (PCA) and multiple regression analysis (MRA) in order to find the correlation with the results of viable bacterial counts. By using the potentiometric sensor, the pork freshness was evaluated and the PCA and MRA corresponded to the degree of bacterial increases more simply and rapidly than other methods such as viable bacterial counts or a biosensor.     

Flow immunoassay of trinitrophenol based on a surface plasmon resonance sensor using a one-pot immunoreaction with a high molecular weight conjugate

A surface plasmon resonance (SPR) immunosensor based on a competitive immunoreaction for the determination of trinitrophenol (TNP) is described. A goat anti-mouse IgG (1st antibody), which recognizes an Fc moiety of an antibody, was immobilized on a gold film of an SPR sensor chip by physical adsorption. A TNP solution containing a fixed concentration of a mouse anti-TNP monoclonal antibody (2nd antibody) and a TNP-keyhole limpet hemocyanin (KLH) conjugate was incubated in one-pot and introduced into the sensor chip. The TNP-KLH conjugate competes with TNP for binding with the 2nd antibody. The resulting complex of the 2nd antibody with the TNP-KLH conjugate was bound to the 1st antibody, which is immobilized on the sensor chip. The SPR sensor signal based on resonance angle shift is dependent on the concentration of TNP in the incubation solution in the range from 25 ppt to 25 ppb, and the coefficient of variation of the SPR signals for the 25 ppb TNP solution was determined to be 13% (n = 4). The experimental results for the adsorption constant of the 1st antibody on the sensor chip and the binding constant of the 1st antibody complex with the 2nd antibody are discussed, together with theoretical considerations.     

Potentiometric and Spectroscopic Characterization of Copolypeptide-Surfactant Complexes Formed by a Cooperative Binding System

The binding behavior of an anionic surfactant, sodium dodecyl sulfate (SDS), to a series of L-lysine-containing copolypeptides in aqueous solutions was investigated in relation to the conformational change of copolypeptide-surfactant complexes with the use of potentiometric and spectroscopic techniques. The present results of CD spectra and the binding isotherm of SDS by copolypeptides of opposite charges can lead us to conclude that SDS binds cooperatively to the positively charged side groups of a series of copolypeptides used in this work, resulting in the formation of a micelle-like cluster due to an additional hydrophobic interaction among bound SDS ions. Solid-state properties of the stoichiometric copolypeptide-SDS complexes were also examined by using CD and FT-IR spectroscopies; (Lys, Tyr) (1:1) and (4:1) systems adopt a beta-pleated sheet conformation, while (Lys, Trp) (4:1) and (Lys, Phe) (1:1) systems adopt an alpha-helical conformation. Based on the results of FT-IR spectra, in all cases surfactant alkyl chains of SDS in the solid complexes were in an extended conformation. Copyright 2000 Academic Press.     

Studies on non-thiazolidinedione antidiabetic agents. 3. Preparation and biological activity of the metabolites of TAK-559

Preparation and biological activity of the metabolites of the potent antihyperglycemic and antihyperlipidemic agent, (E)-4-(4-[(5-methyl-2-phenyl-1,3-oxazol-4-yl)methoxy]benzyloxyimino)-4-phenylbutyric acid (TAK-559) (1), were investigated. Metabolites M-I (2), M-II (3), M-III (4) and M-IV (5) were synthesized and their biological activities were evaluated by in vitro and in vivo experiments. Compounds 2-4 activate human peroxisome proliferator-activated receptor gamma one (hPPARgamma1) and hPPARalpha, but their activities are weaker than those of TAK-559 (1). Compound 5 only activates hPPARgamma1 weakly. TAK-559 (1) showed potent in vivo plasma glucose and triglyceride lowering activities in Wistar fatty rats after intraperitoneal administration, while its metabolites (2-5) showed comparatively weak activities.     

Coulometric investigation of the conditions for drying bauxites for chemical analysis

In order to dry a bauxite sample to constant weight for the determination of alumina content, the following procedure is recommended. The sample should be placed in a small flat weighing bottle and heated at 105-110 degrees for 5 hr in a dried atmosphere, then cooled in a desiccator containing magnesium perchlorate. After weighing, it should be reheated at 105-110 degrees for 40-60 min then cooled and weighed under the same conditions to ensure it has attained constant weight.     

Looking glass inhibitors: L-DMDP, a more potent and specific inhibitor of alpha-glucosidases than the enantiomeric natural product DMDP

L-DMDP, prepared from D-gulonolactone, is a highly specific inhibitor of a number of plant and mammalian alpha-glucosidases [between 2 and 4 orders of magnitude more potent than the enantiomeric natural product DMDP] but is not an inhibitor of bacterial and yeast alpha-glucosidases. Additionally N-butyl-DMDP is a potent inhibitor of ceramide-specific glucosyltransferase but N-butyl-L-DMDP shows no inhibition.