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Genetics in natural polyploidy in loach
Arai, Katsutoshi 한국어류학회 1995 韓國魚類學會誌 Vol.7 No.2
Loaches widely distribute in the Eurasian Continent and are important for food both in Japan and Korea. Chromosome manipulation including induction of gynogenesis, androgenesis, and polyploidy is powerful tool for potential applications in aquaculture as well as for basic genetic research. The loach Misgrunus anguillicaudatus in Japan has a diploid karyotype(2n=50), but a small number of natural polyploidy have been found. In diploid vertebrates, artificially induced gynogenesis and androgenesis normally give rise to inviable haploid embryos, In contrast, gynogenetic and androgenetic progeny generated by using gametes of the natural tetraploid loach with 100 chromosomes were viable without any treatments for chromosome duplication. The results conclusively demonstrate that the loach with 100 chromosomes is not an evolved-back diploidy, but a true tetraploidy with four sets of homologous chromosomes, The same conclusion was obtained in the tetraploid form of spinous loach Cobitis biwae. Triploid loach produced by hybridizations between normal diploids and natural tetraploids showed male - sterility. While, triploid females laid two sizes of eggs, large and small, and gave viable progeny after backcrossing to normal diploid loach and chromosome manipulation(induced gynogenesis by UV - irradiated spermatozoa and inhibition of the second polar body release by pressure shock). Cytogenetic and flowcytometric analyses on these progeny demonstrate that triploid loach produce 3n large and 1n small eggs. Multilocus - DNA - fingerprintind revealed clonal nature of gynogenetic triploids which were produced by fertilizing the large eggs with UV - irradiated spematozoa. This suggests involvement of unreduced oogenesis in the formation of the large eggs. Cytology and biochemical genetics are now underway to disclose mechanisms responsible for the small egg formation. Pentaploid females produced by inhibiting the polar body release after 4n × 2n hybridizations laid only 2n eggs with medium size. Pentaploid males produced very small number of aneuploid spermatozoa. Hexaploid loach were produced by inhibiting the polar body release after 4n × 4n crosses. Flowcytometry of the testes of hexaploid males showed formation of functuonal 3n spermatozoa. The presence of polyploid in the loach species suggests specially divierged sex determination mechanisms. Deviation of sex from the theoretical ratio was observed when the loach were reared in unusually high temperature.
Arai, Yoshie,Park, Sunghyun,Choi, Bogyu,Ko, Kyoung-Won,Choi, Won Chul,Lee, Joong-Myung,Han, Dong-Wook,Park, Hun-Kuk,Han, Inbo,Lee, Jong Hun,Lee, Soo-Hong MDPI 2016 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.17 No.6
<P>Human adipose-derived stem cells (hASCs) have a capacity to undergo adipogenic, chondrogenic, and osteogenic differentiation. Recently, hASCs were applied to various fields including cell therapy for tissue regeneration. However, it is hard to predict the direction of differentiation of hASCs in real-time. Matrix metalloproteinases (MMPs) are one family of proteolytic enzymes that plays a pivotal role in regulating the biology of stem cells. MMPs secreted by hASCs are expected to show different expression patterns depending on the differentiation state of hASCs because biological functions exhibit different patterns during the differentiation of stem cells. Here, we investigated proteolytic enzyme activity, especially MMP-2 activity, in hASCs during their differentiation. The activities of proteolytic enzymes and MMP-2 were higher during chondrogenic differentiation than during adipogenic and osteogenic differentiation. During chondrogenic differentiation, mRNA expression of MMP-2 and the level of the active form of MMP-2 were increased, which also correlated with Col II. It is concluded that proteolytic enzyme activity and the level of the active form of MMP-2 were increased during chondrogenic differentiation, which was accelerated in the presence of Col II protein. According to our findings, MMP-2 could be a candidate maker for real-time detection of chondrogenic differentiation of hASCs.</P>
Hantavirus in Northern Short-tailed Shrew, United States
Arai, Satoru,Song, Jin-Won,Sumibcay, Laarni,Bennett, Shannon N.,Nerurkar, Vivek R.,Parmenter, Cheryl,Cook, Joseph A.,Yates, Terry L.,Yanagihara, Richard Centers for Disease Control and Prevention 2007 Emerging infectious diseases Vol.13 No.9
<P>Phylogenetic analyses, based on partial medium- and large-segment sequences, support an ancient evolutionary origin of a genetically distinct hantavirus detected by reverse transcription–PCR in tissues of northern short-tailed shrews (<I>Blarina brevicauda</I>) captured in Minnesota in August 1998. To our knowledge, this is the first evidence of hantaviruses harbored by shrews in the Americas.</P>
Vortices, Q-balls and Domain Walls on Dielectric M2-branes
Arai, Masato,Montonen, Claus,Sasaki, Shin IOP Publishing Ltd 2009 Journal of high energy physics Vol.2009 No.3
We study BPS solitons in &calN; = 6 U(<I>N</I>) × U(<I>N</I>) Chern-Simons-matter theory deformed by an F-term mass. The F-term mass generically breaks &calN; = 6 supersymmetry down to &calN; = 2. At vacua, M2-branes are polarized into a fuzzy <I>S</I><SUP>3</SUP> forming a spherical M5-brane with topology <B>R</B><SUP>1,2</SUP> × <I>S</I><SUP>3</SUP>. The polarization is interpreted as Myers' dielectric effect caused by an anti-self-dual 4-form flux <I>T</I><SUB>4</SUB> in the eleven-dimensional supergravity. Assuming a polarized M2-brane configuration, the model effectively reduces to the well-known abelian Chern-Simons-Higgs model studied in detail by Jackiw-Lee-Weinberg. We find that the potential for the fuzzy <I>S</I><SUP>3</SUP> radius agrees with the one calculated from the M5-brane point of view at large <I>N</I>. This effective model admits not only BPS topological vortex and domain wall solutions but also non-topological solitons that keep 1/4 of the manifest &calN; = 2 supersymmetry. We also comment on the reduction of our configuration to ten dimensions.
Arai Hikaru,Asami Koki,Ito Hajime,Katayama Noboru 한국물리학회 2022 Current Applied Physics Vol.39 No.-
Catalyst layers of proton exchange membrane fuel cells (PEMFC) are formed by electrospray deposition (ESD) method. The cathode catalyst layers are formed and characterized by varying the settings of the system, such as flow rate, applied voltage and the distance between the capillary and the substrate. The dryness of the aggregates during deposition is evaluated using the Damkh¨oler number (Da), and the structure of the catalyst layer is observed using SEM, which shows that the catalyst layer is porous when dry and non-porous when insufficiently dry. In the case of insufficient drying, the structure changed significantly depending on the position. Single cell tests show that the maximum power density varies from 105 to 253 mWcm-2 depending on the settings, even with the same catalyst ink and the same amount of platinum. Electrochemical impedance spectroscopy shows that the charge transfer and mass transport resistances tend to decrease with increase in Da.
Vacua and walls of mass-deformed Kähler nonlinear sigma models on Sp(N)/U(N)
Arai, Masato,Golubtsova, Anastasia,Park, Chanyong,Shin, Sunyoung American Physical Society 2018 Physical Review D Vol.97 No.10
<P>We study vacua and walls of mass-deformed Miller nonlinear sigma models on Sp(N)/U(N). We identify elementary walls with the simple roots of USp(2N) and discuss compressed walls, penetrable walls, and multiwalls by using the moduli matrix formalism.</P>