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Volume 47 (2022)
- Issue 6 Pages 310-
- Issue 5 Pages 240-
- Issue 4 Pages 184-
- Issue 3 Pages 122-
- Issue 2 Pages 60-
- Issue 1 Pages 2-
Volume 47, Issue 5
Displaying 1-12 of 12 articles from this issue
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Special Topic : Reviews based on the Special Lectures in the 44th Annual Meeting
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Toru Maruyama, Michinari Hieda2022 Volume 47 Issue 5 Pages 240-245
Published: 2022
Released on J-STAGE: September 30, 2022
JOURNAL RESTRICTED ACCESSCirculating in vivo human erythrocytes are subjected to several kinds of hemodynamic stresses such as oxidative stress, mechanical stress, and osmotic stress. Therefore, erythrocytes show the biconcaved disc configuration, that is beneficial to the cell surface gas exchange and the passive deformation by shear stress in microcirculation. These kinds of hemodynamic stresses accelerate erythrocyte aging by accumulating damages. This review article introduces the effects of artificial oxidative stress on morphological, biochemical and rheological changes observed in erythrocyte suspension. Further, impaired deformability of erythrocytes obtained from patients with hypertension or diabetes is introduced in relation to erythrocyte membrane damage caused by augmented oxidative stress and/or reduced antioxidative defense mechanisms reported in these diseases.View full abstractDownload PDF (964K)
Special Topic : Frontiers in artificial oxygen carriers
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Hiromi Sakai2022 Volume 47 Issue 5 Pages 246-251
Published: 2022
Released on J-STAGE: September 30, 2022
JOURNAL RESTRICTED ACCESSHemoglobin (Hb) is the most abundant protein in blood, and compartmentalized in red blood cells (RBCs). Once Hb is released from RBCs in blood circulation, it induces some toxicities. Various types of hemoglobin–based oxygen carriers (HBOCs) have been developed to mitigate the Hb toxicities. One method is to encapsulate Hb in biocompatible phospholipid vesicles (liposomes) to prepare Hb–vesicles (HbV). A new encapsulation method using a rotation–revolution mixer provided efficient preparation of HbV that has considerably facilitated R&D of HbV. Preclinical safety and efficacy of HbV as a transfusion alternative have been extensively studied by the academic consortium, and the results urged us to initiate a clinical trial. In this review paper are focused on the biocompatible lipid bilayer membrane and the efficient preparation method of liposome encapsulated Hb.View full abstractDownload PDF (1301K) -
Teruyuki Komatsu2022 Volume 47 Issue 5 Pages 252-256
Published: 2022
Released on J-STAGE: September 30, 2022
JOURNAL RESTRICTED ACCESSModified hemoglobins (Hbs) as a red blood cell (RBC) substitute have a long history and artificial O2 carriers of various kinds have been developed so far. Although this type of preparation is essentially aqueous solution of protein, unlike the dispersion of RBCs, it possesses many attractive features such as easy production method, low cost, and simple composition. In fact, most of the artificial O2 carriers currently under investigation are modified Hb preparations. We synthesized a core–shell structured “(hemoglobin–albumin)cluster” (Hb–HSA3, formulation name : Hemo Act) in which the core Hb is covalently wrapped with three molecules of human serum albumin (HSA). Its structure, characteristics, safety, and efficacy have been clarified in detail. We have also developed entirely synthetic protein clusters using recombinant Hb and recombinant HSA. Replacing the peripheral HSA to recombinant canine serum albumin and recombinant feline serum albumin yielded artificial O2 carriers for dogs and cats.View full abstractDownload PDF (869K) -
Toru Hyakutake2022 Volume 47 Issue 5 Pages 257-262
Published: 2022
Released on J-STAGE: September 30, 2022
JOURNAL RESTRICTED ACCESSIn this paper, two topics were presented: In the first topic, we investigated the RBC partitioning properties in a microvascular bifurcation model using both numerical simulation and in vitro experiment. When HbVs were perfused, they compensated for the small RBC flux and facilitated oxygen supply into the lower–flow branch. In addition, HbV perfusion has an effect of reducing oxygen heterogeneity in the capillary network. In the second topic, a microvascular model including the tissue region was constructed to simulate the reaction–diffusion phenomena of oxygenated HBOCs and oxygen. As a result, the presence of a plasma layer affected the oxygen transport in RBCs. In addition to oxygen affinity, the diffusion coefficient that depends on the HBOC size also had a significant impact on oxygen transport to the tissue.View full abstractDownload PDF (780K)
Special Topic : Viewing and measuring lipid membranes and biomembranes
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Minoru Nakano2022 Volume 47 Issue 5 Pages 263-268
Published: 2022
Released on J-STAGE: September 30, 2022
JOURNAL RESTRICTED ACCESSQuantitative understanding and control of phospholipid dynamics in biological membranes is an important issue in biophysics and cell biology, but handling biological membranes as multicomponent, heterogeneous, and complex systems is not a straightforward task. On the other hand, the use of artificial lipid bilayers (vesicles) as a simplified model of biomembranes allows physicochemical measurements and quantitative discussions since their lipid composition and membrane curvature can be manipulated flexibly. We have established a method for evaluating lipid dynamics in phospholipid vesicle systems by time–resolved small–angle neutron scattering. This method exploits the fact that the scattering length densities of normal (protiated) and deuterated lipids differ significantly, and that the neutron scattering intensity decreases when these lipids are exchanged between vesicles. This review will present the evaluation of the kinetics of spontaneous and protein–mediated phospholipid transfers between vesicles and describe the mechanisms by which increased membrane curvature facilitates these processes.View full abstractDownload PDF (829K) -
Takaharu Okajima2022 Volume 47 Issue 5 Pages 269-272
Published: 2022
Released on J-STAGE: September 30, 2022
JOURNAL RESTRICTED ACCESSAtomic force microscopy (AFM) is useful for measuring the mechanical properties of living cells. Recently, the indentation–based AFM allowed us to obtain images of cell height and stiffness in developing embryos during cell division where the actin filaments and myosin are dynamically accumulated and released in the cortical region. This review addresses the advantage of AFM to probe the mechanical properties of embryonic cells in terms of other techniques for embryo mechanics and shows how the mechanical properties of embryonic cells, measured by AFM, change during cell division.View full abstractDownload PDF (725K) -
Shigetoshi Oiki2022 Volume 47 Issue 5 Pages 273-280
Published: 2022
Released on J-STAGE: September 30, 2022
JOURNAL RESTRICTED ACCESSThe biological membrane is a complex system, having a two–faced nature of fluidity and mosaicity. The fluidity characterizes the continuum physical entity of lipid bilayer, while the mosaicity expresses heterogeneity of lipid molecules and membrane proteins. Here, I focus on the ion channel as a representative of membrane proteins, permitting single–molecule functional measurements. To circumvent the complexity of biological membranes, a membrane reconstitution system called contact bubble bilayer (CBB) was established, in which chemical and physical features of lipid bilayers are readily manipulated. First, I describe the mechanical feature of lipid bilayer governed by the Helfrich formalism. Then, the principles of the CBB method for the membrane tension measurements are presented in comparison with the patch–clamp counterpart. Next, membrane–channel interactions using the KcsA potassium channel are examined, and the tension–dependency of the non–mechanosensitive KcsA channel is shown. Moreover, I demonstrate a novel hysteretic response of the KcsA channel to the membrane tension. Finally, future studies exploring bi–directional interactions between membrane and channels are discussed.View full abstractDownload PDF (918K) -
Takuma Tsuji2022 Volume 47 Issue 5 Pages 281-285
Published: 2022
Released on J-STAGE: September 30, 2022
JOURNAL RESTRICTED ACCESSThe composition of the cell membrane is not homogeneous, and each organelle has its own unique lipid composition. Asymmetric distribution of membrane lipids between bilayers is also known and microdomains with different lipid compositions exist on the same membrane leaflet, such as lipid rafts. These heterogeneous lipid distributions not only affect the physical properties of biological membranes, but are also thought to play various physiological roles by regulating the localization and function of membrane proteins. However, there are only limited tools for analyzing the localization of membrane lipids, and our understanding of membrane lipids is still lagging behind that of proteins. We have examined intracellular and transbilayer distribution of membrane lipids by using quick–freezing and freeze–fracture replica labeling (QF–FRL) electron microscopy. In this review, I summarize our recent findings on the regulating mechanisms of membrane lipid distribution revealed by using QF–FRL.View full abstractDownload PDF (866K)
Special Topic : Membrane Award for Young Scientists (2022)
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Hiroki Nagasawa2022 Volume 47 Issue 5 Pages 286-290
Published: 2022
Released on J-STAGE: September 30, 2022
JOURNAL RESTRICTED ACCESSwe developed a novel technique to fabricate microporous silica membranes by utilizing atmospheric–pressure plasma–enhanced chemical vapor deposition (AP–PECVD). AP–PECVD provided a facile and scalable strategy to synthesize microporous silica membranes under ambient temperature and pressure. The “remote” AP–PECVD, in which the deposition was performed remotely in the downstream of the discharge region, enabled the synthesis of silica membranes even at room temperature. The remote AP–PECVD was further employed for the synthesis of polymer–supported silica membranes, which can potentially minimize the cost of membrane synthesis via the use of inexpensive polymers instead of conventional ceramics to support silica membranes. The “direct” AP–PECVD, where the deposition was performed directly in the discharge region, was also developed to achieve ultrafast synthesis of silica membranes. Direct deposition in the discharge enabled immediate formation of silica thin layer on the order of minutes. The AP–PECVD–derived membranes exhibited outstanding permselectivity comparable to conventional microporous inorganic membranes, providing a nonthermal alternative for the synthesis of silica membranes for molecular separation.View full abstractDownload PDF (833K) -
Hiroyuki Nakao2022 Volume 47 Issue 5 Pages 291-296
Published: 2022
Released on J-STAGE: September 30, 2022
JOURNAL RESTRICTED ACCESSIn eukaryotic cells, phospholipid transbilayer movement (flip–flop) is regulated by membrane proteins for cell homeostasis and signaling. Phospholipid scramblases, which promote phospholipid flip–flop in an energy–independent manner, are involved in several physiological functions including apoptosis and blood coagulation. However, their lipid scrambling mechanisms still need to be investigated. Model membrane systems allow us to derive general information about lipid–protein interactions. This review introduces the development of de novo designed phospholipid flip–flop promoting peptides and their molecular mechanisms. Moreover, the application of these peptides to the regulation of cell–to–cell communications is presented.View full abstractDownload PDF (781K) -
Kohjiro Nagao2022 Volume 47 Issue 5 Pages 297-302
Published: 2022
Released on J-STAGE: September 30, 2022
JOURNAL RESTRICTED ACCESSThe cell membrane is composed of more than a thousand phospholipid species in animals. The structure and distribution of phospholipid molecules affect the physicochemical properties of membranes and activity of membrane proteins. Thus, appropriate regulation of phospholipid molecules is thought to be required for a variety of cellular functions. However, owing to the structural diversity of phospholipid molecules, the roles of various cellular phospholipids remain unclear. I have been investigating the roles of phospholipid molecules using Drosophila cells, since their phospholipid composition and regulatory mechanisms are relatively simple. Here, I introduce the recent findings obtained from the studies focusing on the structure and distribution of phospholipid molecules in Drosophila cells.View full abstractDownload PDF (727K)
Products Spotlight :
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Shoichi Doi2022 Volume 47 Issue 5 Pages 303-306
Published: 2022
Released on J-STAGE: September 30, 2022
JOURNAL RESTRICTED ACCESSThe ion–exchange membrane using polyolefin reinforcement developed in 2016 by ASTOM corporation exhibits excellent electrochemical performance. A comparison of SEM / EDX image and the index calculated from Micro Heterogeneous Model, of the developed membrane and a heterogeneous membrane cleared the reason of the difference in electrochemical performance.View full abstractDownload PDF (948K)
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