Online ISSN : 1884-6440
Print ISSN : 0385-1036
ISSN-L : 0385-1036
27 巻, 2 号
選択された号の論文の7件中1~7を表示しています
  • 村瀬 琴乃, Kenneth Ritchie, 藤原 敬宏, 飯野 亮太, 中田 千枝子, 楠見 明弘
    2002 年 27 巻 2 号 p. 58-66
    発行日: 2002/03/01
    公開日: 2011/03/04
    ジャーナル フリー
    Single particle tracking (SPT), laser tweezers, and single fluorophore video imaging (SFVI) have facilitated observation of molecular interactions in the plasma membrane of living cells at a level of single molecules. These techniques revealed that the membrane skeleton provides both corralling and binding effects on the movement of membrane proteins and lipids. Corralled membrane proteins undergo hop diffusion from one compartment to an adjacent one (membrane skeleton fence model). Lipids macroscopic diffusion is also largely limited by the hop rate across the compartment boundaries formed by rows of pickets made of various transmembrane proteins anchored to the actin membrane skeleton (anchored-protein picket model). These mechanisms can play a pivotal role in the molecular organization of the plasma membrane.
  • 榎本 和生, 梅田 真郷
    2002 年 27 巻 2 号 p. 67-73
    発行日: 2002/03/01
    公開日: 2011/03/04
    ジャーナル フリー
    Phosphatidylethanolamine (PE) is a major membrane phospholipid that is mainly localized in the internal leaflet of the plasma membrane. We have shown that PE was exposed on the external leaflet of the cleavage furrow as a result of enhanced transbilayer movement of the phospholipids during cytokinesis. To further investigate the role of PE in cytokinesis, we employed two different approaches : manipulation of cell surface PE by a PE-binding peptide, and the establishment of a mutant cell line specifically defective in PE biosynthesis. Both approaches clearly demonstrate that surface-exposed PE is essential for disassembly of the contractile ring at the final stage of cytokinesis. Based on these findings, we proposed that the transbilayer redistribution of PE plays a critical role in mediating coordinated movements between the cytoskeleton and the plasma membrane that are required for the proper progression of cytokinesis.
  • 伊藤 俊樹
    2002 年 27 巻 2 号 p. 74-82
    発行日: 2002/03/01
    公開日: 2011/03/04
    ジャーナル フリー
    The cytoskeleton and the plasma membrane are two major components that define cellular shape, and control cell movement. The actin cytoskeleton lies just beneath the plasma membrane suggesting regulatory mechanisms based upon direct interactions between them. In fact, almost all of actin regulating proteins are known to bind phospholipids, especially phosphoinositides, to enhance or to suppress their activity. Such examples include the “classical” actin regulating proteins (profilin, gelsolin etc.) as well as recently unveiled ERM proteins and WASP families. In addition, interference of interaction between phosphoinositide and those proteins by a specific antibody or a phosphoinositide-binding peptide results in an inhibition of actin polymerization in response to extracellular stimuli. Furthermore, disturbance of intracellular phosphoinositide content by overexpression of phosphoinositide kinases or phosphatases affects the structure of actin cytoskeleton. These data clearly indicate the close relationship between phosphoinositide and actin cytoskeleton, and suggest the existence of the regulatory mechanism of cytoskeleton by phosphoinositide metabolizing enzymes. This review will focus on actin regulating proteins controlled by phosphoinositides and discuss their roles for cytoskeletal rearrangements upon extracellular signals.
  • 宮田 英威
    2002 年 27 巻 2 号 p. 83-88
    発行日: 2002/03/01
    公開日: 2011/03/04
    ジャーナル フリー
    Cell cortex is a sub-membranous structure lying between the cell membrane and cytoplasm. In red blood cells it is a form of network consisted of spectrin, crosslinked by short actin filaments and other actin and spectrin binding proteins. This network, by associating with the lipid membrane, protects the red cell from loosing its lipid membrane during the passage of the red cell through capillary vessel. In Dictyostelium discoideum the cell cortex is consisted of a layer of actin filaments where myosin II filaments intersperse, and is contractile in the presence of ATP. The cortical tension thus generated is thought to play a role in controlling the cell shape change and transport of materials in the cortex or those bound to the cell surface receptors. I will overview studies that have investigated the role of the cell cortex in regulating the cell shape.
  • 朴 連春, 後藤 雅宏, 古崎 新太郎
    2002 年 27 巻 2 号 p. 89-93
    発行日: 2002/03/01
    公開日: 2011/03/04
    ジャーナル フリー
    Reversed micelles, which are nanostructural molecular assemblies, are utilized for the mutation detection of deoxyribonucleic acids (DNAs). The hybridization rate of a complementary single stranded DNA was measured in reversed micelles by detecting the decrease in the absorbance at 260nm with a UV/VIS spectrophotometer. The hybridization rate was significantly reduced when the complementary DNA has a mismatched sequence. The number and the position of the mutation also influenced the hybridization rate in reversed micelles. Therefore, we can readily know the existence of a mutation for a targeted DNA by measuring the hybridization rate. The analysis of sample oligonucleotides (20mer) that relates to the tumor suppressor gene P53 was conducted in the AOT reversed micelle. The hybridization rate was very sensitive to the number and the location of the mismatched sequence in the sample DNAs.
  • 横田 賢, 玉木 慎也, 林 京子, 上野 雅晴
    2002 年 27 巻 2 号 p. 94-100
    発行日: 2002/03/01
    公開日: 2011/03/04
    ジャーナル フリー
    Membrane protein transfer from influenza virus-infected cells to liposomes was examined in several experimental conditions using gel-filtration, SDS PAGE and fluorescent microscopy. In gel-filtration it was found that membrane protein spontaneously transferred from cell membrane to liposomal membrane during incubation of liposomes with cells, accompanied by some leaks of non-membrane protein.The amount of membrane protein incorporated into liposomal membrane was proportional to that of total protein released from cells. SDS PAGE experiment after immunoprecipitation confirmed the transfer of influenza antigenic protein from influenza virus-infected cell's membrane to liposomal membrane. Fluorescent image was observed all around liposome surface in microscopy using fluorescence antibody, suggesting the transferred antigenic protein was incorporated throughout into liposomal membrane.
  • 杉本 正夫, 坪井 尚弘, 辻井 弘次
    2002 年 27 巻 2 号 p. 101-104
    発行日: 2002/03/01
    公開日: 2011/03/04
    ジャーナル フリー
    First gas transmission rate analyzer based on gas chromatography was marketed in 1970 in Japan after application of patent. The method has been widely applied for transmission test of gas, vapor (vapor of water and organic solvents), liquid transmission test using PV cell method, and it is expanding the applications of PV cell too. Why the method is widely accepted and evaluated by customers is depending upon the diversity of gas transmission rate analysis method coupled with gas chromatography which can analyze even the mixed gases in permeated gas.
    Considering US EPA's requirement to strengthen automotive evaporative emission, the method may be more useful mean to test transmission of gasoline through high barrier materials and to evaluate high polymer electrolysis membrane (using moisturizing technique of both rooms of permeation cell to measure transmitted hydrogen). This testing system will be more widely applied and an essential tool for research and development work.
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