Expression and purification of recombinant human annexin A2 in Pichia pastoris and utility of expression product for detecting annexin A2 antibody

Annexin A2, a Ca2+-dependent phospholipid binding protein, is abundantly expressed in various human organs, which exists as either a membrane-associated, cytosolic or soluble form in serum. We constructed expression systems for recombinant human annexin A2 (rhA2) using Pichia pastoris. The systems are designed to secrete rhA2 as either the N- or C-terminally His6-tagged form to facilitate purification. Both types of rhA2 were overexpressed, but in the N-terminal-truncated form as revealed from the results of N-terminal amino acid sequencing and Western blotting. Therefore, further purification of N-terminally His6-tagged rhA2 was not feasible because of the removal of the N-terminal His6-tag sequence. C-terminally His6-tagged rhA2 was expressed as either a glycosylated or a nonglycosylated form, and the nonglycosylated form was purified using the combination of nickel-immobilized affinity, concanavalin A and cation exchanged column chromatographies. The solid-phase binding of rhA2 was examined by enzyme-linked immunosorbent assay (ELISA), which revealed the specific reactivity of rhA2 against an anti-annexin A2 monoclonal antibody. These results suggest that the expression system using P. pastoris is useful for the preparation of rhA2 that is applicable to the ELISA detection of the anti-annexin A2 antibody.     

Analytic cross sections for electron impact collisions with nitrogen molecules

Cross sections for 74 processes in collisions of electrons with nitrogen molecules (N₂) and singly ionized nitrogen molecules have been collected. The literature has been surveyed through the middle of 2004. The data sets collected are presented in separate graphs for each process. Recommended cross sections are expressed by analytic expressions.     

Pheromone Analysis of Wild Female Moths with a PBAN C-Terminal Peptide Injection for an Estimation of Assortative Mating in Adzuki Bean Borer, Ostrinia scapulalis

The adzuki bean borer, Ostrinia scapulalis, has distinct genetic variation in the blend of two sex pheromone components, (E)- and (Z)-11-tetradecenyl acetates. This variation is largely controlled by a single autosomal locus with two alleles, E and Z. E-type (EE) females produce a pheromone with a mean E:Z ratio at 99:1 whereas Z-type (ZZ) and I-type (ZE) produce pheromones with mean of 3:97 and 64:36, respectively. Interestingly, in many natural populations of O. scapulalis in Japan, this pheromone polymorphism appears to be stably maintained. We tried to predict the changes in relative abundance of each pheromone type by estimating the pheromone production genotype of wild females and their male mates. The pheromone titer in the wild, mated females was increased without changing the blend ratio by an injection of a peptide with pheromone biosynthesis activating activity (TKYFSPRL-NH2). The frequencies of E-, I-, and Z-types at Matsudo were 15, 52, and 33%, respectively, and did not deviate from the Hardy-Weinberg expectations. The estimated mating patterns were concordant with the assumption that no assortative mating was occurring in this population, and this is suggested as a cause of sustained polymorphism at Matsudo.     

Effects of main particle diameter on improving particle flowability for compressed packing fraction in a smaller particle admixing system

Particle flowability can be improved by admixing particles smaller than the original particles (main particles). However, the mechanisms by which this technique improves flowability are not yet fully understood. In this study, we examined compressed packing in a particle bed, which is affected by particle flowability. To estimate the mechanism of improvement, we investigated the effects of the main particle diameter on the improvement of compressed packing fractions experimentally.The main particles were 397 and 1460 nm in diameter and the admixed particles were 8, 21, 62, and 104 nm in diameter. The main and admixed particles were mixed in various mass ratios, and the compressed packing fractions of the mixtures were measured. SEM images were used to analyze the coverage diameter and the surface coverage ratio of the admixed particles on the main particles. The main particle packing fraction was improved as the diameter ratio (=main particles/admixed particles) increased. This was explained by a linked rigid-3-bodies model with leverage. Furthermore, the actual surface coverage ratio at which the most improved packing fraction was obtained decreased with increasing main particle diameter. This was explained by the difference in the curvature of the main particle surface.     

Serum matrix metalloproteinase-3 in hemodialysis patients with dialysis-related amyloidosis

Background: Matrix metalloproteinase‐3 (MMP‐3) has been linked to osteoarticular destruction in rheumatic arthritis. To investigate the role of MMP‐3 in dialysis‐related amyloidosis (DRA), we determined serum MMP‐3 in long‐term hemodialysis (HD) patients with and without clinical manifestations of DRA. Methods: Thirty‐three subjects (63% female, 3% diabetic) enrolled in the study between September 2001 and June 2003. All patients underwent standard HD three times per week, using high‐flux dialyzers. Four patients had active DRA complications (DRA patients), whereas the others (n = 29) had no evidence of DRA. We determined serum concentrations of MMP‐3, C‐reactive protein (CRP), β₂‐microglobulin (β₂M), and interleukin‐6 (IL‐6). We also studied the effects of hemodiafiltration (HDF) on inflammatory measures by transferring the DRA patients from regular HD to predilution HDF. Results: The DRA group had been on dialysis significantly longer than the control group. Significant positive correlations were observed between MMP‐3 and IL‐6 (R² = 0.5143, p < 0.0001) and MMP‐3 and CRP (R² = 0.6492, p < 0.0001). IL‐6 levels increased after a single dialysis treatment, but this effect was minimal with predilution HDF (the increment of IL‐6 levels did not exceed 10 pg/mL). Serum MMP‐3 levels decreased in parallel with the decrease of IL‐6. Conclusions: MMP‐3 serum levels increase in accordance with clinical manifestations of DRA and elevated circulating levels of IL‐6. For the evaluation of the pathophysiologic state of DRA, serum MMP‐3 may be a useful predictor indicative of chronic inflammation and osteoarticular disorders in DRA patients.     

Development of novel Ru catalyst of preferential CO oxidation for residential polymer electrolyte fuel cell systems

CO preferential oxidation on a novel Ru catalyst greatly improved in activity and selectivity over a wide temperature range by the pre-treatment of H₂ reduction was characterized. The high performance was obtained by increasing the population of surface Ru(0) which improved O₂ activation at low temperatures. Methanation of CO on the catalyst can also contribute to the final CO clean-up from ca. 100 to <1 ppm at low temperatures where the influence of CO₂ methanation can be ignored.     

Pervaporation characteristics of methyl methacrylate–methacrylic acid copolymer membranes ionically crosslinked with metal ions for a benzene/cyclohexane mixture

Methyl methacrylate–methacrylic acid copolymer (MMA–MAA) membranes ionically crosslinked with Fe³⁺ and Co²⁺ ions (MMA–MAA–Fe³⁺ and –Co²⁺) were prepared, and characteristics of permeation and separation for a benzene/cyclohexane mixture of 50 wt % benzene through these membranes in pervaporation (PV) were studied. Although the introduction of the metal ions to the MMA–MAA membrane enhanced both benzene permselectivity and permeability for a benzene/cyclohexane mixture, the PV characteristics between the MMA–MAA–Fe³⁺ and –Co²⁺ membranes were significantly different. The difference in the PV characteristics between these membranes was strongly governed by the difference of these membrane structures based on the glass transition temperature, contact angle to methylene iodide, degree of swelling, and mixture composition absorbed in the membrane, and so on. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 233–241, 1999     

Processing, Mechanical Properties, and Oxidation Behavior of Silicon Oxynitride Ceramics

Silicon oxynitride ceramics were prepared by hot-pressing an equimolar Si₃N₄+ SiO₂ mixture with 3 mol% CeO₂. The Ce₂O₃/SiO₂ ratio of intergranular phase (liquid phase) increased as the formation of Si₂N₂O proceeded. The intergranular liquid remained as a glass on cooling until the Ce₂O₃/SiO₂ ratio exceeded a certain value, at which point the liquid crystallized. There were great differences in thermal and mechanical properties and oxideation behavior between the specimen containing intergranular glassy phase and the one containing intergranular crystalline phase (Ce₅(SiO₄)₃N–Ce_4.67(SiO₄)₃O). The specimen containing the intergranular glassy phase showed excellent hightemperature strength and oxidation resistance.     

Thermal stresses and effective properties calculated for fiber composites using actual cylindrically-anisotropic properties of interfacial carbon coating

Thermal stresses in composites composed of fiber (Nicalon™ or carbon fiber), pyrolytic-carbon coating and matrix (SiC) were calculated by the use of the actual properties of carbon coating, which are elastically and thermally cylindrically-anisotropic (transversely-isotropic about radial direction). They were compared with calculations with other anisotropies for the coating, including an often assumed anisotropy which is transversely-isotropic about fiber axis. It was shown that the differences in radial and hoop stresses between the actual and assumed ones could be significant. In addition, effective moduli and CTEs of a composite fiber (fiber/carbon-coating) and those of a composite matrix (carbon-coating/matrix) were derived and used to interpret the resulted thermal stresses.