Transport of monooleoylglycerol mediated by bile salt micelles across porous membranes

In order to study how the bile salts and lipids behave in the vicinity of microvillus, the transport properties of a sodium salt of deoxycholic acid (NaDC) and its mixture with monooleoylglycerol (MO) through artificial membranes were investigated in 0.15 M NaCl saline solution at 37°C.The hydrodynamic radius of MO-solubilized micelles was estimated to be approximately 17–20 Å from the transport study. The thermodynamically stable MO-NaDC mixed micelles formed above critical micelle concentration in the higher region of mole fraction of NaDC in the mixture (X _NaDC>ca. 0.6), can behave as a single species in transport process and freely pass through the porous membranes of both pore sizes, 0.01 m and 0.1 m.The permeabilities of MO-NaDC mixed micelles are large compared with those of pure NaDC micelles. MO molecules solubilized may probably enhance the interaction between MO and NaDC molecules by better contacting with the respective hydrophobic groups in a mixed micelle (the flexible structure of MO molecule enables it), and in this situation, the smaller micelles compared with those of pure NaDC must be more favorable.     

Kinetic Study of 1-β-Cyanoethyl Aziridine for Ring-Opening Polymerization Initiated with Alkyl Sulfate

The kinetics of the cationic polymerization of 1-β-cyanoethyl aziridine initiated 3-hydroxy- 1-propane sulfonic acid sultone and methyl tosylate have been studied. The course of polymerization involved the propagation stage and termination reaction due to the reaction between the growing chain and imino groups in the polymer chain. The propagation constants and termination constants were obtained. The enthalpies of activation for the propagation and termination reactions are ΔH_p? = 12.9 kcal/mol and ΔH_t? = 12.4 kcal/mol, and the entropies of activation are ΔS_p? = -31 cal/deg·mol and ΔS_t? = -39 cal/deg·mol. Otherwise, the polymerization initiated with methyl tosylate involved an early stage which was initiated very quickly.     

Synthesis and Properties of Phosphorus-Containing Aromatic Polyethers

The phosphorus-containing aromatic polyethers were prepared from bis(p-chlorophenyl)phenylphosphine oxide (BCPO) with the sodium salt of several bisphenols by high temperature solution polycondensation. The best result (yield 84%, n _sp /c = 0.15) was obtained from BCPO with bisphenol A (BPA) in dimethyl sulfoxide. However, the polymerization in the solvents such as N, N′-dimethyl-2-pyrrolidone, hexamethylphosphoramide, and N,N′-dimethylformamide, and the polymerization with the other bisphenols HO-C₆H₄-X-C₆H₄?OH, where X = CO, S0₂, CH₃P(O), C₆H₅P(O) in place of BPA gave gumlike polymers. The polymer prepared from BCPO and BPA did not decompose up to ca. 300°C under air or nitrogen atmosphere, but it decomposed slowly at 300–520°C, and decomposed rapidly at 520–540°C. The activation energy (δE) for the maximum rate of weight loss was 47.8 kcal/mole.     

Solubilization and precipitation of cholesterol in aqueous solution of bile salts and their mixtures

Solubilization of cholesterol by mixed micelles of sodium chenodeoxycholate with sodium ursodeoxycholate was investigated in carbonate-tetraborate buffer (Kolthoff) solution at pH 10 and 37°C. It was found that the mixing of the two bile salts gives a negatively synergetic effect on solubilization of cholesterol. The solubilizing power of bile salts for cholesterol was remarkably influenced with the change in mole fraction of sodium ursodeoxycholate (X _UDC).The behavior of bile salt solutions saturated with cholesterol was examined by measuring the surface tension. Two break points were observed in the curves of surface tension vs. concentration. The break points seem to correspond to a CMC in the absence of solubilized cholesterol and another CMC in the presence of solubilized cholesterol inside bile salt micelle.     

Spin and fluorescence label studies on bile salt micelles

The interior structure of micelles formed by bile salts, which differ in the number and location of the hydroxyl groups attached to the steroid nucleus, was studied by the spin label and fluorescence label methods. The results show that the interior structure of micelles formed by bile salts possessing two hydroxyl groups is more rigid than that of micelles formed by trihydroxy bile salts regardless of the terminal hydrophilic group. Even in the case of dihydroxy bile salts possessing two hydroxyl groups in the same location, the interior structures of their micelles are different from each other depending on the orientation of their hydroxyl groups. It is considered that hydroxyl groups as well as the terminal hydrophilic group play an important role in the micellar formation of bile salts.     

Three-component complexes of cyclodextrins. Exciplex formation in cyclodextrin cavity

The fluorescence quenching of naphthalene, 1-methylnaphthalene, and acenaphthene by trimethylamine (TMA) was studied in aqueous -cyclodextrin (-CD) solutions to know the structural requirements for guest molecules to form three-component complexes. The apparent rates for the fluorescence quenching of the naphthalene derivatives by TMA markedly increased in the presence of -CD. The fluorescence quenching of 1-methylnaphthalene and acenaphthene by TMA was accelerated by -CD more efficently than that of naphthalene. These results suggest the structures of the three-component complexes as the arene-capped -CD including TMA in its cavity.     

A facile method of transesterification using phosphorus ylid

The transesterification of carboxylic esters catalyzed with phosphorus ylid under neutral and mild conditions has been investigated. The reactions of esters having an electron withdrawing group with methanol proceeded rapidly and with high yield, whereas the reverse reactions proceeded slowly or not at all.     

Automatic polymerase chain reaction product detection system for food safety monitoring using zinc finger protein fused to luciferase

An automatic polymerase chain reaction (PCR) product detection system for food safety monitoring using zinc finger (ZF) protein fused to luciferase was developed. ZF protein fused to luciferase specifically binds to target double stranded DNA sequence and has luciferase enzymatic activity. Therefore, PCR products that comprise ZF protein recognition sequence can be detected by measuring the luciferase activity of the fusion protein. We previously reported that PCR products from Legionella pneumophila and Escherichia coli (E. coli) O157 genomic DNA were detected by Zif268, a natural ZF protein, fused to luciferase. In this study, Zif268–luciferase was applied to detect the presence of Salmonella and coliforms. Moreover, an artificial zinc finger protein (B2) fused to luciferase was constructed for a Norovirus detection system. In the luciferase activity detection assay, several bound/free separation process is required. Therefore, an analyzer that automatically performed the bound/free separation process was developed to detect PCR products using the ZF–luciferase fusion protein. By means of the automatic analyzer with ZF–luciferase fusion protein, target pathogenic genomes were specifically detected in the presence of other pathogenic genomes. Moreover, we succeeded in the detection of 10 copies of E. coli BL21 without extraction of genomic DNA by the automatic analyzer and E. coli was detected with a logarithmic dependency in the range of 1.0 × 10 to 1.0 × 10⁶ copies.     

Synthesis of Linear Poly(1-Benzyltrimethyleneimine) by the Hofmann Reaction of Poly(1-Cyanoethyltrimethyleneimine) Quaternized with Benzylbromide

The synthesis of a linear polymer having a tertiary amino group in a part of the main chain has been attempted by several methods. However, it was difficult for the linear polyamine to form because of the complicated reaction of the amino group. In the polymerization of weakly basic cyclic amines, e.g., 1-cyanoethylazetidine or 1-cyanoethylaziridine, high molecular weight polymers, poly-1-cyanoethyltrimethyleneimine (poly-CET) and poly-1-cyanoethyl-ethyleneimine (poly-CEE), were obtained. An attempt was made to convert poly-CET and poly-CEE into poly(l-benzylalkyleneimine)s (poly-BET and poly-BEE). Linear poly-BET was prepared by the alkylation of poly-CET (MW about 6000) with benzylbromide, followed by the elimination of the cyanoethyl group of polymer by heating. The poly-BET obtained was a white, greasy substance with a molecular weight of about 5000; its structure was determined by NMR spectroscopy. The cyanoethyl groups were replaced completely by benzyl groups. However, poly-BEE with a complete exchange to benzyl group was not obtained from poly-CEE due to the remaining cyanoethyl groups. Residual cyanoethyl groups replaced about 40% of the amino groups in poly-CEE.     

Kinetic Studies of the Ring-Opening Polymerization of 1-β-Cyanoethylazetidine

The ring-opening polymerization rate of 1-β-cyanoethylazetidine (CA) with 3-hydroxy-1-propanesulfonic acid sultone (HPSS) as an initiator has been investigated in acetonitrile. The polymerization of CA with HPSS proceeded by way of a zwitterion formed by the addition reaction of CA and HPSS. The course of polymerization involved, as an early stage, slow initiation due to the low reactivity of the zwitterion. The propagation constants were obtained as were the enthalpy of activation for propagation (ΔH_p? = 12 kcal/mol) and the entropy of activation for propagation (ΔS_p? = ?31 cal/K·mol).