Microtechnologies for membrane protein studies

Despite the rapid and enormous progress in biotechnologies, the biochemical analysis of membrane proteins is still a difficult task. The presence of the large hydrophobic region buried in the lipid bilayer membrane (transmembrane domain) makes it difficult to analyze membrane proteins in standard assays developed for water-soluble proteins. To handle membrane proteins, the lipid bilayer membrane may be used as a platform to sustain their functionalities. Relatively slow progress in developing micro total analysis systems (μTAS) for membrane protein analysis directly reflects the difficulty of handling lipid membranes, which is a common problem in bulk measurement technologies. Nonetheless, researchers are continuing to develop efficient and sensitive analytical microsystems for the study of membrane proteins. Here, we review the latest developments, which enable detection of events caused by membrane proteins, such as ion channel current, membrane transport, and receptor/ligand interaction, by utilizing microfabricated structures. High-throughput and highly sensitive detection systems for membrane proteins are now becoming a realistic goal. Although most of these systems are still in the early stages of development, we believe this field will become one of the most important applications of μTAS for pharmaceutical and clinical screenings as well as for basic biochemical research

XPS及びAESによる層状半導体GaSeの酸化過程の研究

The oxidation process of layered compound Ca Se which has no dangling bond on the cleaved surface has been studied by XPS and AES techniques. At room temperature, the cleaved surface is not oxidized in oxvgen gas atmosphere. By Ar ion sputtering, the surface becomes to show the behavior of metallic Ca due to the dissipation of the first sublayer of Se in a primitive layer Se-Ca-Ca-Se. The thin layer of the metallic Ca is easily oxidized. In the case of thermal oxidation of cleaved Ca Se in air atmosphere, the oxygen diffuses into the primitive layer and combines with Ca, which causes the severance of the intralayer bonding between Se and Ca atoms. At temperature higher than 450℃, the oxygen is also intercalated between the primitive layers from the sides perpendicular to the layers. No Se oxides are observed under any of the oxidation conditions

PIXE analysis of magnetic spherules in Paleozoic-Mesozoic bedded chert

Particle Induced X-ray Emission (PIXE) was applied to the elemental characterization of magnetic microspherules collected from the Paleozoic and Mesozoic bedded chert in Southwest Japan. Comparison of the titanium and chromium contents of the spherules with the magnetic components of meteorites and volcanic ash showed that this technique offers promising potential as a new method for distinguishing between spherules of terrestrial and extraterrestrial origin

Dynamic X-ray Diffraction Technique for Measuring Rheo-optical Properties of Crystalline Polymeric Materials

A dynamic X-ray diffraction technique, which can follow the responses of polymer crystals (crystallization, orientation, and lattice deformation) to a mechanical excitation of sinusoidal strain induced to a bulk specimen, was described. The descriptions for such responses are qualitatively made by using a narrow sector technique, which can measure the X-ray diffraction intensity distribution at a particular phase angle of the sinusoidal strain as a function of static and dynamic strains, temperature, and angular frequency. A typical result is demonstrated in terms of the investigation of orientationcrystallization phenomena of natural rubber vulcanizates. More quantitative descriptions can be made by using a half-circle sector technique, which can measure the in-phase and out-of phase components of the dynamic X-ray diffraction intensity distribution. From these, one can obtain the dynamic strain-induced crystallization and orientation coefficients and the dynamic response of lattice deformation of a specific crystal plane both as functions of temperature and frequency. After a brief survey of the principle of the half-circle sector technique, frequency dependence of the dynamic strain-induced crystallization coefficients of the (002) and (200) crystal planes of natural rubber vulcanizates is demonstrated in terms of the two frequency dispersion regions around 10⁻² and 10¹ Hz at a room temperature. The former and latter dispersions must be correlated with the crystallization processes of the so-called α- and γ-filaments, respectively. In addition, frequency and temperature dispersions of the dynamic strain-induced orientation coefficient and the dynamic response of lattice deformation of the (110) crystal plane of polyethylene are demonstrated in relation to the so-called a₁ and a₂ dispersions of dynamic mechanical modulus function of this material

Characteristics of gene expression in frozen shoulder

Background: Severe frozen shoulder (FS) is often resistant to treatment and can thus result in long-term functional impairment. However, its etiology remains unknown. We hypothesized that gene expression of FS would vary by synovial location. Methods: The synovial tissues of patients with FS were collected prospectively and analyzed for the expression of 19 genes. Synovial tissues from patients with rotator cuff tear (RCT) or shoulder instability (SI) were also analyzed as controls. A total of 10 samples were analyzed from each group. The specimens were arthroscopically taken from three different locations: rotator interval (RI), axillary recess (AX), and subacromial bursa (SAB). Total RNA was extracted from the collected tissues and was analyzed by real-time polymerase chain reaction for the following genes: matrix metalloproteinases (MMPs); tissue inhibitors of metalloproteinases (TIMPs); inflammatory cytokines (IL1B, TNF, and IL6); type I and II procollagen (COL1A1 and COL2A1); growth factors (IGF1 and TGFB1); neural factors (NGF and NGFR); SOX9; and ACTA2. Results: Site-specific analysis showed that MMP13, IL-6, SOX9, and COL1A1 were increased in all three sites. Four genes (MMP3, MMP9, COL2A1, and NGFR) were increased in the AX, MMP3 in the RI, and NGFR in the SAB were increased in the FS group than in the RCT and SI groups. In the FS group, there was a correlation between the expression of genes related to chondrogenesis (MMP2, IGF1, SOX9, COL2A1, NGF, and NGFR) or fibrosis (MMP9, TGFB1, and COL1A1). Conclusion: The expression levels of numerous MMPs, pro-inflammatory cytokines, and collagen-related genes were increased in the FS group, suggesting that catabolic and anabolic changes have simultaneously occurred. In addition, genes related to chondrogenesis or fibrosis were highly expressed in the FS group, which might have affected the range of motion limitation of the shoulder. Compared to RI and SAB, the AX was the most common site of increased expression in FS. Analyzing the lower region of the shoulder joint may lead to the elucidation of the pathogenesis of FS