Analytical method for beta-amyloid fibrils using CE-laser induced fluorescence and its application to screening for inhibitors of beta-amyloid protein aggregation

More than 20 million people are suffering from Alzheimer's disease, and the number of patients will dramatically increase with the arrival of an aging society unless preventive or curative medications are discovered. A fast and sensitive analytical method for beta-amyloid (Abeta) aggregates was developed by the combination of CE-laser induced fluorescence and the fluorescence reagent, thioflavine T. The developed method separates two different fibrils within 5 min. The first peak, which migrated at approximately 4 min, was supposed to be derived from a precursor of a fibril that migrated at approximately 3.5 min. The developed method was also applicable to the high-throughput screening of the Abeta aggregation inhibitors, which was expected to be an effective therapeutic agent candidate of Alzheimer's disease. Three compounds (daunomycin, 3-indolepropionic acid (3-IPA), melatonin) were used for the assay. The order of the antiaggregation activity of these compounds was daunomycin > 3-IPA > melatonin, which was the same as that of the reported one. These results suggest that this analytical method may be used to analyze the Abeta fibrils and identify potential therapeutic agents for the treatment of Alzheimer's disease.     

High-throughput immunophenotyping by surface plasmon resonance imaging

Cell binding assays on antibody arrays permit the rapid immunophenotyping of living cells. The throughput of the analysis, however, is still limited due to our inability to perform parallel and quantitative detection of cells captured on the array. To address this limitation, we employed here an imaging technique based on surface plasmon resonance (SPR). SPR has been frequently used to monitor capture of proteins on antibody microarrays, while few cases were reported for capture of cells. Antibody arrays were prepared through the photopatterning of an alkanethiol monolayer on a gold-evaporated glass plate and the subsequent immobilization of various antibodies onto 4-9 separate spots created by photopatterning. A glass slip was mounted onto the array with a thin spacer to construct a parallel-plate chamber. Leukemia cells were injected into the chamber to conduct a binding assay, while refractive index changes at the vicinity of the array surface were monitored by SPR imaging. We observed that SPR signals were intensified on specific antibody spots but not on nonspecific spots. Confocal laser scanning microscopy revealed that the observed SPR signals were attributed to cell deformations caused by multivalent interactions with immobilized antibody, which effectively elevated the refractive index of a medium phase within an evanescent field. This effect could be suitably utilized to monitor quantitatively cell binding to multiple spots from a heterogeneous cell population.     

Design and evaluation of an antiparallel coupled resonator for chemical sensor applications

In this paper, a new type of quartz crystal resonator in which the electrodes are located on one side has been developed for chemical sensing. The resonator has two electrodes for exciting thickness shear mode (TSM) vibrations on one side of the crystal and a conductive layer on the other side. These electrodes are capacitively coupled with the electric fields in opposite directions, forming an antiparallel coupled resonator (ACR). The resonant characteristics of the ACR were evaluated as a function of gap width between the two electrodes used to excite the TSM. The conductance value was observed to increase with decreasing gap width. We also discovered that the gap should be parallel with the crystallographic x-axis to obtain the highest sensitivity. The frequency response to a viscous loading was almost same as that of a standard quartz crystal microbalance (QCM). The ACR sensor is an attractive alternative to a QCM chemical sensor because it can be easily integrated into packaging and film coatings.     

摩擦纺的纱线尾部结构

1 引言 各种纺纱系统产生各种不同的纱结构。在摩擦纺中,由于纱线和进入纺纱区分布的纤维流的恒速移动,纱尾形成一个“自由端”且是锥形的。纱线仅绕自轴旋转。摩擦纺中纱线形成机理至今还不完全清楚,纱线的结构参量也不能完全被人们理解。对摩擦纺纱线的结构已作了大量的研究工作。喂入成纱区的纤维、纤维流、成纱区和输送通道的气流以及其他的机械参数和纺纱条件决定了     

Subcellular localization of fructosyl amino acid oxidases in peroxisomes of Aspergillus terreus and Penicillium janthinellum

Fructosyl amino acid oxidase (FAOD) is the enzyme catalyzing the oxidative deglycation of Amadori compounds, such as fructosyl amino acids, yielding the corresponding amino acids, glucosone, and H(2)O(2). In a previous report, we determined the primary structures of cDNAs coding for FAODs from two fungal strains Aspergillus terreus AP1 and Penicillium janthinellum and we found that both fungal FAODs included the putative peroxisome targeting signal 1 (PTS1) at the carboxyl terminal (Yoshida, N. et al., Eur. J. Biochem., 242, 499-505, 1996). In this study, we determined the intracellular localization of FAODs in these two fungi. Subcellular fractionation experiments and immuno-electronmicroscopic observations, together with the previous findings indicated that the FAODs were localized in peroxisomes of A. terreus AP1 and P. janthinellum. These FAODs were also found to belong to a new member of "peroxisomal sarcosine oxidase family protein" in eucaryotic cells.     

A novel hemiacetal dehydrogenase activity involved in ethyl acetate synthesis in Candida utilis

Acetate ester synthesis was studied in vitro with the ethyl acetate-producing yeast Candida utilis. The level of enzyme activity observed for the NAD+-dependent hemiacetal dehydrogenase acting on hemiacetal, which was produced non-enzymatically from an alcohol and an aldehyde, was much greater than that for the other enzyme involved in ester synthesis, alcohol acetyltransferase. The level of ethyl acetate synthesis in vivo approximately paralleled the hemiacetal dehydrogenase (HADH) activity. The results suggest that the main pathway for ethyl acetate synthesis in C. utilis involves a novel hemiacetal dehydrogenase activity.     

Isolation of a protease-deficient mutant of Bacillus brevis and efficient secretion of a fungal protein disulfide isomerase by the mutant

The efficient production of a thermostable protein disulfide isomerase (PDI) was successfully achieved using the newly isolated protease-deficient mutant, Bacillus brevis 31-OK. Extracellular protease (exoprotease) activity was about a quarter of that in the parent, and the mutant was deficient in at least one of the major exoproteases. The cDNA encoding the fungal PDI was inserted downstream of the signal peptide-encoding region in an expression-secretion vector for B. brevis. Efficient production of PDI was feasible using B. brevis 31-OK as a host and modified signal sequences composed of three leucine residues inserted in the hydrophobic region of the MWP (middle wall protein) signal sequence. The maximal secretion of PDI into the culture medium was 1.1 g/l, which is about twice that by the parent strain and fifty times greater than the amount of rat and murine PDIs produced by Escherichia coli. The enzymatic properties such as the specific activity and thermal stability of the recombinant PDI are similar to those of natural PDI derived from Humicola insolens mycelia. B. brevis 31-OK was able to maintain its exoprotease activity at a low level throughout the cultivation and is considered to be useful host for production of a protease-sensitive protein and for increase of protein productivity due to stable accumulation.     

大豆蛋白纤维及其混纺产品的性能含量分析

主要介绍大豆蛋白纤维的物机和化学性能,并利用其物化性能测定混纺产品中大豆蛋白纤维的含量。     

竹炭粘胶纤维/彩棉/细绒棉混纺针织纱的开发

介绍了竹炭改性粘胶纤维、彩棉纤维和细绒棉的原料性能,混纺针织纱的工艺流程及各工序的工艺参数和技术措施.生产中注意因原料性能差异易产生条干不匀,以及竹炭粘胶纤维成卷困难的问题,提高混和均匀度.     

Purification and characterization of enzyme responsible for N-myristoylation of octapeptide in aqueous solution without ATP and coenzyme a from Pseudomonas aeruginosa

The enzyme that catalyzes N-acyl linkage between myristic acid and the NH(2)-terminal glycine residue of the octapeptide Gly-Asn-Ala-Ala-Ala-Ala-Arg-Arg-NH(2) in aqueous solution without ATP and coenzyme A was found in Pseudomonas aeruginosa. The enzyme was purified from cell-free crude extract using DEAE-Cellulose, Sephadex G-200, CM-Sephadex C-50, and hydroxyapatite column chromatographies, and then purified approximately 1900-fold with about 1.5% recovery of enzyme activity from the crude extract. Finally, the purified enzyme showed a main band on SDS polyacrylamide gel electrophoresis after staining with Coomassie Brilliant Blue. The band corresponded to a molecular mass of approximately 60 kDa. The K(m)s of the purified enzyme for the substrate myristic acid and the octapeptide were 0.36 and 2.6 mM, respectively. When myristoyl-CoA instead of myristic acid was used as the substrate for the enzyme reaction, myristoyl octapeptide could be synthesized as observed in the case of myristic acid. The K(m) of myristoyl-CoA was 0.17 mM.