Amyloid-β oligomers suppress subunit-specific glutamate receptor increase during LTP

Introduction: Amyloid‐β oligomers (AβOs) are assumed to impair the ability of learning and memory by suppressing the induction of synaptic plasticity, such as long‐term potentiation (LTP) in the early stage of Alzheimer's disease. However, the direct molecular mechanism of how AβOs affect excitatory synaptic plasticity remains to be elucidated. Methods: In order to study the effects of AβOs on LTP‐associated changes of AMPA (alpha‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid)‐type glutamate receptor (AMPAR) movement, we performed live‐cell imaging of fluorescently labeled AMPAR subunit GluA1 or GluA2 with total internal reflection fluorescence microscopy. Results: Incubation of cultured hippocampal neurons with AβOs for 1–2 days inhibited the increase in GluA1 number and GluA1 exocytosis frequency in both postsynaptic and extrasynaptic membranes during LTP. In contrast, AβOs did not inhibit the increase in GluA2 number or exocytosis frequency. Discussion: These results suggest that AβOs primarily inhibit the increase in the number of GluA1 homomers and suppress hippocampal LTP expression

Stability of ferromagnetism in the Hubbard model on the kagom\'e lattice

The Hubbard model on the kagom\'e lattice has highly degenerate ground states (the flat lowest band) in the corresponding single-electron problem and exhibits the so-called flat-band ferromagnetism in the many-electron ground states as was found by Mielke. Here we study the model obtained by adding extra hopping terms to the above model. The lowest single-electron band becomes dispersive, and there is no band gap between the lowest band and the other band. We prove that, at half-filling of the lowest band, the ground states of this perturbed model remain saturated ferromagnetic if the lowest band is nearly flat.Comment: 4 pages, 1 figur

Iron Emission Lines on the Galactic Ridge Observed with Suzaku

In order to elucidate origin of the Galactic Ridge X-ray Emission, we analyzed Suzaku data taken at various regions along the Galactic plane and studied their Fe-K emission line features. Suzaku resolved the Fe line complex into three narrow lines at ~6.4 keV,~6.7 keV and ~6.97 keV, which are K-lines from neutral (or low-ionized), He-like, and H-like iron ions, respectively. The 6.7 keV line is clearly seen in all the observed regions and its longitudinal distribution is consistent with that determined from previous observations. The 6.4 keV emission line was also found in various Galactic plane regions (b~0). Differences in flux ratios of the 6.4 keV/6.7 keV and 6.97 keV/6.7 keV lines between the Galactic plane and the Galactic center regions are studied and its implication is discussed.Comment: Accepted for publication in PASJ Suzaku 3rd special issu

Two activators of in vitro fertilization in mice from licorice

AbstractSystems for artificial insemination have been established in some animals. However, due to limited availability of sperm and oocytes, more effective treatment methodologies are required. Recently, it was demonstrated that the rate of in vitro fertilization (IVF) in mice was improved by adding a water extract of licorice (Glycyrrhiza uralensis), but not glycyrrhizic acid, to the artificial insemination culture medium. In this study, we examined licorice extract for active compounds using bioassay-guided separation. The results indicated that isoliquiritigenin and formononetin were the active molecules in licorice that contributed to the improved rate of IVF

Lipoprotein(a) stimulates the proliferation of cultured human arterial smooth muscle cells through two pathways

AbstractWe investigated the effect of lipoprotein(a) (Lp(a)) on proliferation of human arterial smooth muscle cells (SMCs) and its mechanisms of action. Low density lipoprotein (LDL), Lp(a) and apolipoprotein(a) (apo(a)) significantly stimulated the proliferation of SMCs. Lp(a) and apo(a) reduced the amount of active transforming growth factor-β (TGF-β) with the mink lung epithelial cell bioassay, however LDL had no effect. Lp(a), but not apo(a), significantly stimulated the proliferation of SMCs even in the presence of a neutralizing antibody for TGF-β. Our results suggest that Lp(a) stimulates the proliferation of SMCs via apo(a)-induced inhibition of TGF-β activation and stimulation of SMCs by the LDL-particle of Lp(a)

Land mobile satellite propagation measurements in Japan using ETS-V satellite

Propagation characteristics of land mobile satellite communications channels have been investigated actively in recent years. Information of propagation characteristics associated with multipath fading and shadowing is required to design commercial land mobile satellite communications systems, including protocol and error correction method. CRL (Communications Research Laboratory) has carried out propagation measurements using the Engineering Test Satellite-V (ETS-V) at L band (1.5 GHz) through main roads in Japan by a medium gain antenna with an autotracking capability. This paper presents the propagation statistics obtained in this campaign

精子細胞特異的に発現するイントロンレス遺伝子について

胚発生の非常に初期に未分化生殖細胞が生じ、個体発生の過程に生殖巣に遊走し到達する。その後、生殖巣の分化に伴って、雌では卵原細胞、雄では精原細胞へと分化する。精巣においては、精原細胞は幹細胞として増殖・分化し、その後精母細胞の分化と減数分裂、減数分裂後の半数体精子細胞特有なクロマチン形成を伴う形態形成が整然と起こる。一連の精細胞分化とそれを支える細胞を含む精巣では、ほとんどすべての遺伝子が発現し、また多くの特異的遺伝子が含まれていることが明らかにされている。さらに、それらの遺伝子の中にレトロトランスポジションによって生じたと考えられているイントロンレス遺伝子が、数多く機能していることが明らかにされた。本稿では、精子形成過程で発現するイントロンレス遺伝子についてまとめ、数多く存在する理由について考察する

Development of a novel evaluation method for air particles using surface plasmon resonance spectroscopy analysis

The aim of this study was to develop a novel evaluation method for air particles using surface plasmon resonance spectroscopy (SPR) analysis. An L1 sensor chip modified with immobilized liposome was used as a model of the membrane of epithelial cells in organs of respiration. A test suspension of dispersed air particles was flowed onto the sensor chip. The interaction between the surface of the sensor chip and particulates in the sample solution was detected by SPR. It is deduced that the SPR measurement provides information about the adsorption/desorption behavior of the particles on the membrane. Environmentally certified reference materials, diesel particulate matter, vehicle exhaust particulates, urban particulate matter, coal fly ash, and rocks, were used as air particulate samples. Filtrates of suspensions of these samples were analyzed by SPR. Each sample revealed characteristic SPR sensor-gram patterns. For example, diesel particulate matter strongly interacted with the lipid bilayer, and was hardly dissociated. On the other hand, coal fly ash and rock particles interacted poorly with the membrane. The presented method could be used to evaluate or characterize air particles.ArticleANALYST. 138(18):5437-5443 (2013)journal articl

In Vitro Fertilization Activators for Future

Artificial insemination is an indispensable technology for cattle breeding and is used for treating infertility in humans. Thus, new or improved methods are needed to increase the efficiency of artificial insemination. In vitro fertilization (IVF) has been developed in mice. Although many mouse lines produced using IVF have been preserved by freezing embryos and/or fertilized eggs, the more efficient IVF using freezing preservation or long‐term refrigeration of sperm is expected to preserve mouse lines more easily. In this chapter, we introduce the active compounds in licorice to improve the rate of IVF. We previously reported that the rate of IVF in mice was improved by adding a water extract of licorice (Glycyrrhiza uralensis), but not glycyrrhizin, to the artificial insemination culture medium. Recently, we analyzed the active ethyl acetate fraction containing high levels of flavonoids. This fraction was further purified by bioassay‐guided separation to isolate isoliquiritigenin and formononetin, which contributed to the improved rate of IVF. Isoliquiritigenin and formononetin may be useful therapeutic agents for infertility treatment