Studies on ion-exchange membranes. XXXII. Heterogeneity in ion-exchange membranes

Twelve kinds of cation-exchange membranes were treated with hydrogen peroxide. Some of them (Selemion CMV, Nepton CR-61, Scrion C-100, SAM-1) were completely destroyed. Heterogeneity is believed to be present in that part of their chemical structures that is decomposable by the treatment. The other membranes were converted into porous membranes by the decomposition of the resinous part. Water permeabilities and electric resistances of the porous membranes were examined to evaluate the pore radius. It was concluded that the “paste method” membranes have a heterogeneity or localized distribution of the resinous part under 50 mμ. The “paste method” membranes seemed to resemble the “graft method” membranes in chemical structure and to be much different from the mosaic-type membranes such as Permaplex and MC-3142. These results were also supported by extraction of the membranes with appropriate solvents and observation by electron microscopy.     

Morphology of composite film prepared by polymerizing styrene in poly(vinyl chloride) film

Styrene and the styrene-additive mixtures (kerosene, dioxane, ethylene dichloride, or dioctylphthalate) were soaked into a poly(vinylchloride) film and then styrene was polymerized. Subsequently, poly(styrene) was extracted with CCl₄ and the microporous membrane was obtained, of which the morphology was studied. It is elucidated that the additives affect the morphology of the resultant composite films.     

Coal liquefaction by in-situ hydrogen generation.: 2. Zinc-water model compound reactions

Model compound studies were carried out to elucidate the reaction mechanisms taking place during the liquefaction of coal with the hydrogen produced from the reaction of zinc and water. In compounds of the type Ph-(CH₂)_n-Ph the splitting of the aliphatic bridge was easier with higher n values. Ether type compounds such as diphenylether were unreactive although the C-O bond in dibenzylether was easily cleaved. Condensed ring aromatic compounds gave low conversion with hydrogenation being facilitated by an increase in ring number. Phenolic compounds such as phenol did not react well, but the reactivity increased with increase in aromatic ring size. The cleavage of the aliphatic bridge was accelerated by the OH group, for example, in the case of 4-hydroxydiphenylmethane bond scission was about 15 times higher than that of diphenylmethane. Heterocyclic compounds were unreactive.     

Characterization of Aspergillus oryzae glycoside hydrolase family 43 β-xylosidase expressed in Escherichia coli

This is the first report of glycoside hydrolase family 43 β-xylosidase from Aspergillus oryzae. To characterize this enzyme, the recombinant enzyme was expressed in Escherichia coli. Unlike known β-xylosidases from fungal origins, the enzyme did not show substrate ambiguity and was stable at alkaline pH.     

Two-dimensional multiarray formation of hepatocyte spheroids on a microfabricated PEG-brush surface

A two-dimensional microarray of ten thousand (100 x 100) hepatocyte heterospheroids, underlaid with endothelial cells, was successfully constructed with 100 microm spacing in an active area of 20 x 20 mm on microfabricated glass substrates that were coated with poly(ethylene glycol) brushes. Cocultivation of hepatocytes with endothelial cells was essential to stabilize hepatocyte viability and liver-specific functions, allowing us to obtain hepatocyte spheroids with a diameter of 100 microm, functioning as a miniaturized liver to secret albumin for at least one month. The most important feature of this study is that these substrates are defined to provide an unprecedented control of substrate properties for modulating cell behavior, employing both surface engineering and synthetic polymer chemistry. The spheroid array constructed here is highly useful as a platform of tissue and cell-based biosensors and detects a wide variety of clinically, pharmacologically, and toxicologically active compounds through a cellular physiological response.     

Smart polyion complex micelles for targeted intracellular delivery of PEGylated antisense oligonucleotides containing acid-labile linkages

A novel pH-sensitive and targetable antisense ODN delivery system based on multimolecular assembly into polyion complex (PIC) micelles of poly(L-lysine) (PLL) and a lactosylated poly(ethylene glycol)-antisense ODN conjugate (Lac-PEG-ODN) containing an acid-labile linkage (beta-propionate) between the PEG and ODN segments has been developed. The PIC micelles thus prepared had clustered lactose moieties on their peripheries and achieved a significant antisense effect against luciferase gene expression in HuH-7 cells (hepatoma cells), far more efficiently than that produced by the nonmicelle systems (ODN and Lac-PEG-ODN) alone, as well as by the lactose-free PIC micelle. In line with this pronounced antisense effect, the lactosylated PIC micelles showed better uptake than the lactose-free PIC micelles into HuH-7 cells; this suggested the involvement of an asialoglycoprotein (ASGP) receptor-mediated endocytosis process. Furthermore, a significant decrease in the antisense effect (27 % inhibition) was observed for a lactosylated PIC micelle without an acid-labile linkage (thiomaleimide linkage); this suggested the release of the active (free) antisense ODN molecules into the cellular interior in response to the pH decrease in the endosomal compartment is a key process in the antisense effect. Use of branched poly(ethylenimine) (B-PEI) instead of the PLL for PIC micellization led to a substantial decrease in the antisense effect, probably due to the buffer effect of the B-PEI in the endosome compartment, preventing the cleavage of the acid-labile linkage in the conjugate. The approach reported here is expected to be useful for the construction of smart intracellular delivery systems for antisense ODNs with therapeutic value.     

Genetic Basis to Divergence of Sex Pheromones in Two Closely Related Moths, <Emphasis Type="Italic">Ostrinia scapulalis</Emphasis> and <Emphasis Type="Italic">O. zealis</Emphasis>

Crossing experiments between two closely related moths, Ostrinia scapulalis and O. zealis, were conducted to gain insight into the genetic basis of the divergence of female sex pheromones. The sex pheromone of O. scapulalis comprises (E)-11- and (Z)-11-tetradecenyl acetates (E11 and Z11), and distinct genetic variation is found in the blend of components. This variation is largely controlled by a single autosomal locus with two alleles, A^E(sca) and A^Z(sca). E-type (A^E(sca)A^E(sca)) females produce a pheromone with amean E11:Z11 ratio of 99:1, whereas Z-type (A^Z(sca)A^Z(sca)) and I-type (A^E(sca)A^Z(sca)) females produce a pheromone with a mean of 3:97 and 64:36, respectively. O. zealis is distinctive in that it has a third pheromone component, (Z)-9-tetradecenyl acetate (Z9), in addition to E11 and Z11, and the typical blend ratio is 60:35:5 (Z9:E11:Z11). Our study revealed that Z9 production in O. zealis is mainly regulated by an autosomal recessive gene phr^(zea), which is suggested to be involved in the chain-shortening of a pheromone precursor fatty acid, and linked to A^E(zea), a gene corresponding to A^E(sca) in O. scapulalis. A few mutations in a gene involved in pheromone production could explain the dramatic shift between a two-component pheromone communication system in O. scapulalis and a three-component system in O. zealis.     

Treatment of Chronic Kidney Disease with Extracellular Vesicles from Mesenchymal Stem Cells and CD133+ Expanded Cells: A Comparative Preclinical Analysis

Chronic kidney disease (CKD) is characterized by structural abnormalities and the progressive loss of kidney function. Extracellular vesicles (EVs) from human umbilical cord tissue (hUCT)-derived mesenchymal stem cells (MSCs) and expanded human umbilical cord blood (hUCB)-derived CD133⁺ cells (eCD133⁺) maintain the characteristics of the parent cells, providing a new form of cell-free treatment. We evaluated the effects of EVs from hUCT-derived MSCs and hUCB-derived CD133⁺ cells on rats with CDK induced by an adenine-enriched diet. EVs were isolated by ultracentrifugation and characterized by nanoparticle tracking analysis (NTA) and electron microscopy. The animals were randomized and divided into the MSC-EV group, eEPC-EV group and control group. Infusions occurred on the seventh and 14th days after CKD induction. Evaluations of kidney function were carried out by biochemical and histological analyses. Intense labeling of the α-SMA protein was observed when comparing the control with MSC-EVs. In both groups treated with EVs, a significant increase in serum albumin was observed, and the increase in cystatin C was inhibited. The results indicated improvements in renal function in CKD, demonstrating the therapeutic potential of EVs derived from MSCs and eCD133⁺ cells and suggesting the possibility that in the future, more than one type of EV will be used concurrently.     

Structure of microporous polypropylene sheets containing CaCO3 filler

The microporous polypropylene sheets were prepared by biaxially stretching polypropylene sheets containing CaCO₃ filler (particle size, 0.08–3.0 μm), when the CaCO₃ filler content was 59% by weight and the stretching ratio was 2.8 × 1.8. The microstructure of the sheets were investigated in relation to the CaCO₃ particle size by a N₂ gas permeation method. (1) Effective porosity increases with decreasing mean particle size of filler. (2) The tortuosity factor of the pore is in the range of 25–40 and becomes relatively smaller with decreasing mean particle size of filler. (3) The equivalent pore size becomes relatively smaller with decreasing mean particle size of filler.