14 research outputs found
Polytetrafluoroethylene æš¹èè¡šé¢äžã§ã®çŽ°è芳å¯ææ³ã®éçºããã³è¡äžååã®åãŒã圱é¿
ãç·è«ããPolytetrafluoroethyleneïŒPTFEïŒã¯ããçŽ æš¹èã®äžçš®ã§ãããçäœé©åæ§ãååŠçå®å®æ§ãæ现èæ¥çæ§ã®é«ããããè¡æ¶²æ¥è§Šåã®å»çæ©åšã«åºã䜿çšãããŠããã人工è¡ç®¡ã«ãããŠãPTFEã¯äœ¿çšãããŠãããè¡æ 圢æã®æå¶ã®ããã«ãè¡å°æ¿ä»çæå¶ãè¡ç®¡å
ç®çŽ°èã«ããè¡ç®¡å
å£ã®è£æã¡ïŒå
ç®åïŒã®ç 究ãè¡ãããŠãããPTFE補人工è¡ç®¡ãžã®é·æã«ãããæè¡æ æ§ä»äžã«ã¯ãè¡ç®¡å
ç®çŽ°èã®æ¥çã®å®å®æ§ãéèŠã§ããããã®è©äŸ¡ã«ã¯ãçµæ¥çãªèŠ³å¯ãå¿
èŠã§ããããã®è§£æã«ã¯äœçžå·®é¡åŸ®é¡ã«ãã芳å¯ãé©ããŠãããããããªãããPTFEã¯å
ééçãšæ©æ¢°ç匷床ããšãã«äœããããå®éšã«ååãªåŒ·åºŠã®åãã§ã¯å
ééçãäžååã§ããäœçžå·®é¡åŸ®é¡ã«ãã芳å¯ãã§ããªããäžæ¹ãèèã§ããã°äœçžå·®èŠ³å¯ã¯å¯èœã§ãããšäºæž¬ãããããæ©æ¢°ç匷床ãäžååãšãªããå®éšã«çšããã®ã¯å°é£ã§ããããã®ãããPTFEè¡šé¢ã®çŽ°èã®çµæ¥ç芳å¯ã®å ±åãç¹ã«è¡æ¶²ãšã®æ¥è§Šãæ³å®ããåºç€çãªå ±åã¯ã»ãšãã©ãªãããæ¬ç 究ã¯2ç« ããæ§æãããŠããã第1ç« ã§ã¯å¹é€äžã«ãããŠPTFEè¡šé¢ã®çŽ°èã®äœçžå·®èŠ³å¯ãå¯èœã«ãããããåŸè¿°ã®PTFEã³ãŒãã¬ã©ã¹ãéçºããPTFEè¡šé¢ã®çŽ°èãå¯èŠåã§ããããšã瀺ããã第2ç« ã§ã¯ãéçºããPTFEã³ãŒãã¬ã©ã¹ãçšããŠãè¡æ¶²ãšã®æ¥è§Šãæ³å®ããŠå
ç®çŽ°èãçµæ¥çã«èŠ³å¯ããè¡äžååãšçŽ°èå€ãããªã¯ã¹ãä»ããæ¥çãè©äŸ¡ããã第1ç« ïŒPTFEè¡šé¢ã®çŽ°èã®å¯èŠåãèæ¯ãšç®çããPTFEè¡šé¢ã«ã¯çŽ°èãçŽæ¥æ¥çããããšãã»ãšãã©ãªããã®ã®ãè¡æŒ¿ãä»ããããšã§æ¥çãå¯èœã«ãªãããšãå ±åãããŠãããPTFEã¯å
ééçãäœããããäœçžå·®é¡åŸ®é¡ã«ããç现èã®èŠ³å¯ãã§ãããåºå®ãæè²ããåŸã«èŠ³å¯ãè¡ãããŠããããæ¬ç« ã§ã¯ãã«ããŒã¬ã©ã¹äžã«èèã®PTFEã³ãŒãã£ã³ã°ãæœããPTFEã³ãŒãã¬ã©ã¹ãéçºããããšã§ãPTFEè¡šé¢ã®ç现èã®äœçžå·®é¡åŸ®é¡èŠ³å¯ãå¯èœã«ããããšãç®çãšããããææãšæ¹æ³ããPTFEã³ãŒãã¬ã©ã¹ãšäžè¬çãªPTFEæš¹èïŒPTFEãããã¯ïŒã§çŽ°èæ¥çã®äœãã®åçæ§ãè©äŸ¡ããããã«ãã©ãã倧åèè¡ç®¡å
ç®çŽ°èïŒRAOECïŒãæçš®ãã24æéåŸã®æ¥ç现èæ°ãWST-8 Assayã§æž¬å®ããããè¡æŒ¿ãä»ãã现èæ¥çãPTFEã³ãŒãã¬ã©ã¹ãšPTFEãããã¯ã§åçã§ãããè©äŸ¡ããããã«ãPTFEã³ãŒãã¬ã©ã¹ãšPTFEãããã¯ãã©ããè¡æŒ¿ã«äžæŒå€æµžæŒ¬ããåŸãã©ãã倧åèè¡ç®¡å
ç®çŽ°èïŒRAOECïŒãæçš®ãã24æéåŸã®æ¥ç现èæ°ãWST-8 Assayã§æž¬å®ãããè¡æŒ¿ãä»ããŠPTFEè¡šé¢ã«æ¥çãã现èã®èŠ³å¯ã«ã¯ãåç«åäœçžå·®é¡åŸ®é¡ãçšããããçµæãšèå¯ããPTFEã³ãŒãã¬ã©ã¹ã«ã¯PTFEãããã¯ãšåæ§ã«ãRAOECãã»ãšãã©æ¥çããªãããšã瀺ãããããŸããPTFEã³ãŒãã¬ã©ã¹ã«ã¯PTFEãããã¯ãšåæ§ã«è¡æŒ¿åŠçã«ããRAOECãæ¥çå¯èœã«ãªã£ãããã®æ¥çãã现èã¯PTFEã³ãŒãã¬ã©ã¹ã«ãããŠã®ã¿äœçžå·®èŠ³å¯ãå¯èœã§ãã£ãããŸããPTFEã³ãŒãã¬ã©ã¹è¡šé¢ã«ã¯ãå®éšäžã«å€§ããªå·ãå¥é¢ã¯ç¢ºèªãããªãã£ãããããã®ããšãããPTFEã³ãŒãã¬ã©ã¹ã¯äœçžå·®é¡åŸ®é¡èŠ³å¯ã«ååãªå
ééçãšæ©æ¢°ç匷床ãæã€ããšã瀺ãããããçµè«ãããããŸã§PTFEè¡šé¢ã®çŽ°èã芳å¯ããããã«ã¯ãåºå®ãæè²ãå¿
èŠã§ãã£ãããPTFEã³ãŒãã¬ã©ã¹ãçšããããšã§PTFEè¡šé¢ã®äœçžå·®é¡åŸ®é¡ã«ããå¹é€äžã§ã®ç现è芳å¯ãå¯èœã«ãªã£ãã第2ç« ïŒè¡äžååãšçŽ°èå€ãããªã¯ã¹ãä»ããPTFEãžã®çŽ°èæ¥çã®è©äŸ¡2-1ïŒPTFEãžã®çŽ°èæ¥çã®çæç解æãèæ¯ãšç®çããå®å®ãã现èã®æ¥çã®ææšã®äžã€ãšããŠã现èã仮足ãåºããŠãããã©ãããæãããããããããPTFEè¡šé¢ã¯äœçžå·®é¡åŸ®é¡èŠ³å¯ãå°é£ã§ãããããæ¥ç现èã®åœ¢æ
è©äŸ¡ã¯ã»ãšãã©è¡ãããŠããªããPTFEã³ãŒãã¬ã©ã¹ãçšããããšã§ã现è仮足ã®äœçžå·®èŠ³å¯ã容æã«è¡ãã现èæ¥çã®å®å®æ§ãè©äŸ¡ããããšãå¯èœã§ããããããã§ã第1ç« ã§ç€ºããè¡æŒ¿ãä»ãã现èæ¥çãæ¥çååç¹ç°çãããŸããã©ã®æ¥çååãPTFEè¡šé¢ãžã®çŽ°èæ¥çãä¿é²ããã解æãããåæã«ããããã®æ¥çååãPTFEè¡šé¢ãžã®è¡å°æ¿æ¥çã«åãŒã圱é¿ã解æããããšã§ãè¡å°æ¿æ¥çãä¿é²ããã«å
ç®åãä¿é²ããç©è³ªãæ¢çŽ¢ããããšãç®çãšããããææãšæ¹æ³ããè¡æŒ¿ãä»ãã现èæ¥çãæ¥çååç¹ç°çã解æããããã«ãè¡æŒ¿åŠçPTFEã³ãŒãã¬ã©ã¹ã«ãåºç¯å²ãªæ¥çååé»å®³ããããã§ããã¢ã«ã®ãã³-ã°ãªã·ã³-ã¢ã¹ãã©ã®ã³é
ž-ã»ãªã³ïŒRGDSïŒã§åŠçããRAOECãæçš®ãã24æéåŸã«äœçžå·®é¡åŸ®é¡èŠ³å¯ããã³WST-8 Assayã§çŽ°èæ¥çã解æããããæ¥çååã§ãããã£ãããã¯ãã³ããŽã£ãããã¯ãã³ããã£ããªãã²ã³ãã©ããã³ãã³ã©ãŒã²ã³ã®çŽ°èæ¥çãžã®åœ±é¿ãè©äŸ¡ããããã«ãPTFEã³ãŒãã¬ã©ã¹ããããã®æ¥çååã§åç« ãšåæ§ã«åŠçããRAOECãæçš®ãã24æéåŸã®æ¥çãäœçžå·®é¡åŸ®é¡èŠ³å¯ããã³WST-8 Assayã§è©äŸ¡ããããŸããåæ§ã«ã©ããè¡å°æ¿ãæçš®ã90ååŸã®æ¥çãä¹³é
žè±æ°ŽçŽ é
µçŽ ïŒLDHïŒAssayã§è©äŸ¡ãããããã£ããªãã²ã³ã®çŽ°èæ¥çãžã®åœ±é¿ã解æããããã«ãPTFEã³ãŒãã¬ã©ã¹ãåç« ãšåæ§ã«è¡æŒ¿ãããã¯è¡æž
ã§åŠçããRAOECãæçš®ãã24æéåŸã®æ¥çãäœçžå·®é¡åŸ®é¡èŠ³å¯ããã³WST-8 Assayã§è©äŸ¡ããããŸããã©ããè¡å°æ¿ãæçš®ãã90ååŸã®æ¥çãä¹³é
žè±æ°ŽçŽ é
µçŽ ïŒLDHïŒAssayã§è©äŸ¡ããããçµæãšèå¯ããè¡æŒ¿åŠçPTFEã³ãŒãã¬ã©ã¹è¡šé¢ã®ãRGDSåŠçãããRAOECãäœçžå·®é¡åŸ®é¡èŠ³å¯ããçµæã仮足ãåºããªãäžå®å®ãªæ¥çã確èªãããããã®çŽ°èæ¥çãWST-8 Assayã§è©äŸ¡ãããšãRGDSã«ããæå¶ãããåŸåã瀺ãããããæ¥çååã§åŠçããPTFEã³ãŒãã¬ã©ã¹è¡šé¢ã®RAOECãäœçžå·®é¡åŸ®é¡èŠ³å¯ããçµæããã£ãããã¯ãã³ãã©ããã³ãã³ã©ãŒã²ã³åŠçã«ãããŠRAOECã®ä»®è¶³ãåºããå®å®ãªæ¥çã確èªãããããã®ãšãã®çŽ°èæ¥çãWST-8 Assayã§è©äŸ¡ãããšããã£ãããã¯ãã³åŠçãæãé«ã现èæ¥çã瀺ãã次ãã§ã©ããã³ãšã³ã©ãŒã²ã³åŠçãæ¯èŒçé«ã现èæ¥çã瀺ããããŸããè¡å°æ¿ã®æ¥çã§ã¯ãã£ãããã¯ãã³ãã©ããã³ãã³ã©ãŒã²ã³åŠçãæå¶åŸåã瀺ãããã£ããªãã²ã³åŠçã¯ä¿é²åŸåã瀺ããããçµè«ããPTFEãžã®è¡æŒ¿ãä»ããRAOECã®æ¥çã¯æ¥çååç¹ç°çã§ããããšã瀺åãããæ¥çååã®ãã¡ãã£ãããã¯ãã³ãã©ããã³ãã³ã©ãŒã²ã³ãPTFEãžã®çŽ°èæ¥çãèªå°ããããšã瀺ãããã2-2ïŒPTFEãžã®çŽ°èæ¥çã®çµæ¥ç解æãèæ¯ãšç®çãã2-1ããè¡æŒ¿ããã£ãããã¯ãã³ãã©ããã³ãããã¯ã³ã©ãŒã²ã³åŠçãããPTFEè¡šé¢ã«ãããŠãæçš®24æéåŸã§ã¯ä»®è¶³ãåºãã现èæ¥çã確èªãããã人工è¡ç®¡ã®å
ç®åã«ã¯ããããã®æ¥çãããé·æéã«ãããå®å®ã§ããããã®è¡šé¢ã§çŽ°èå¢æ®ãå¯èœã§ããããšãéèŠã§ãããããã®ããããããã®åŠçããããPTFEè¡šé¢ã®çŽ°èæ¥çã®å®å®æ§ããã³å¢æ®ãçµæ¥çã«è©äŸ¡ããããšã§ã人工è¡ç®¡ã®å
ç®åã«æçšãªååãæ¢çŽ¢ããããšãç®çãšããããææãšæ¹æ³ããè¡æŒ¿ããã£ãããã¯ãã³ãã©ããã³ãããã¯ã³ã©ãŒã²ã³ã§åç« ãšåæ§ã«PTFEã³ãŒãã¬ã©ã¹ãåŠçããRAOECãæçš®ããçµæ¥çã«äœçžå·®é¡åŸ®é¡ã«ãã芳å¯ãã现èæ¥çã®å®å®æ§ããã³å¢æ®ãè©äŸ¡ããããçµæãšèå¯ãããã£ãããã¯ãã³ããã³ã©ããã³åŠçããPTFEè¡šé¢ãžã®RAOECã®æ¥çã¯å®å®çã§ããã现èå¢æ®ãã¿ãããPTFEè¡šé¢ã®å
ç®åãå¯èœã§ãã£ããè¡æŒ¿ããã³ã³ã©ãŒã²ã³ãPTFEè¡šé¢ãžã®çŽ°èæ¥çãèªå°ãããããã®æ¥çã¯äžå®å®ã§ãããæçš®7æ¥ä»¥å
ã«ã»ãšãã©ã®å
ç®çŽ°èãå¥é¢ããå
ç®åã¯èµ·ãããªãã£ãããã£ãããã¯ãã³ãã©ããã³ããPTFEè¡šé¢ã«ããã现èæ¥çã®å®å®æ§ã现èå¢æ®ãä¿é²ããããšã瀺ãããããšããããããã®åŠçãPTFE補人工è¡ç®¡ã«ãæœãããšã§ãå®å®ãªå
ç®åãåŒãèµ·ããããšãå¯èœã«ãªããšäºæž¬ããããäžæ¹ãè¡æŒ¿åŠçåŸã®PTFEè¡šé¢ã«ã¯çŽ°èãæ¥çãããã®ã®ãäžå®å®ã§ããæ°æ¥ã§æ¥ç现èãèªããããªããªã£ãã移æ€ãããPTFE補人工è¡ç®¡ã«ãããŠããè¡æ¶²ãä»ãã现èæ¥çã¯äžå®å®ã§ãããå
ç®åãèµ·ããã«ãããšäºæž¬ãããããçµè«ããæ¬å®éšã§PTFEè¡šé¢ãžã®ãã£ãããã¯ãã³ãã©ããã³åŠçããå®å®ãªçŽ°èæ¥çãåŒãèµ·ãããå
ç®åãå¯èœã«ããããšã瀺ãããããŸããè¡æŒ¿ã§åŠçãããPTFEè¡šé¢ã¯çŽ°èæ¥çãäžå®å®ã§ãããå
ç®åãå°é£ã§ããããšã瀺åãããããç·æ¬ããæ¬ç 究ã§ã¯ãã«ããŒã¬ã©ã¹ã«PTFEãã³ãŒãã£ã³ã°ããPTFEã³ãŒãã¬ã©ã¹ãéçºãããããŸã§å°é£ã§ãã£ãPTFEè¡šé¢ã®äœçžå·®é¡åŸ®é¡èŠ³å¯ãå¯èœã«ããïŒç¬¬1ç« ïŒãäœçžå·®é¡åŸ®é¡ãçšããŠãPTFEã³ãŒãã¬ã©ã¹è¡šé¢ã®RAOECãçµæ¥çã«èŠ³å¯ãããè¡æŒ¿åŠçãããPTFEè¡šé¢ã§ã¯ãæçš®7æ¥åŸã«ã¯ã»ãšãã©ã®çŽ°èãPTFEè¡šé¢ããå¥é¢ããããã®ããšããã移æ€ãããPTFE補人工è¡ç®¡ã§ã¯ããã®è¡šé¢ã«è¡äžã®æ¥çååãä»ããŠçŽ°èãæ¥çããããäžå®å®ã§ããããå
ç®åã®é床ãé
ããªããšäºæž¬ãããïŒç¬¬2ç« ïŒããç 究ã«ããPTFEè¡šé¢ã®çŽ°è芳å¯ã容æãšãªã£ãããã现èã®æ¥çå®å®æ§çãè©äŸ¡ããããšã§ã人工è¡ç®¡ãã¯ãããšããPTFE補ã®å»çæ©åšã®æ¹è¯ã«ç¹ãããšèãããããPolytetrafluoroethylene (PTFE), a kind of fluoropolymer, is widely used as a biomaterial for blood-contacting medical devices because of its properties, such as good biocompatibility, chemical stability and anti-cellular adhesiveness. In blood vessel prostheses, the anti-platelets adhesiveness and endothelialization on the surface of PTFE have been studied for the suppression of thrombus formation. Especially, the endothelialization plays an important role for the longstanding suppression of thrombus formation, the stability of the endothelial adhesiveness on the PTFE is important for that. Inverted phase-contrast microscopy is suitable for the chronological observation, which is needed to estimate the stability of the cellular adhesiveness on the PTFE. However, it is difficult to observe on the surface of thick PTFE, which have sufficient mechanical strength for use in biological experiments, by inverted phase-contrast microscopy because of its low optical transmittance. Although a thin layer of PTFE is likely to have low optical transmittance sufficient for observation under an inverted phase-contrast microscope such a thin layer would have insufficient mechanical strength. In the present study, we developed a PTFE-coated glass with optical transmittance sufficient for observation under an inverted phase-contrast microscope but with sufficient mechanical strength for use in biological experiments. The purpose of this thesis is that the observation of cells under an inverted phase-contrast microscope and the analysis of the effect of blood molecules on the cell adhesion on the surface of PTFE by using the PTFE-coated glass. The background of this thesis was explained in the first chapter. The PTFE-coated glass, which was made by the PTFE coating on the cover glass, was developed to achieve these opposite properties, the optical transmittance and mechanical strength, in the second chapter. Rat aortic endothelial cells (RAOECs) were seeded on the PTFE-coated glass treated with plasma that achieves the cell adhesion to PTFE. The observation of RAOECs on the PTFE-coated glass was tried by using an inverted phase-contras microscope and an inverted fluorescence microscope. It was possible to observe RAOECs on the surface of the PTFE-coated glass by using these microscopes. Any recognizable damage or peeling was recognized in the present study. These results showed that the PTFE-coated glass has sufficient strength and transmittance to be used for biological experiments. The PTFE-coated glass enabled live-cell observation of the PTFE surface using a phase-contrast microscope and also chronological observation. We estimated the effects of the blood molecules and extra cellular matrix on the RAOECs adhesion to PTFE, in third chapter. RAOECs or platelets were seeded on the PTFE-coated glass, which was treated with plasma, serum or cell adhesion molecules contained in blood and extra cellular matrix. The estimation of morphology and adhesion of RAOECs and platelets on the PTFE surface showed that treatment with the fibronectin, laminin, collagen, plasma and serum enhanced the cell adhesion, and tended to suppress the platelets adhesion. The chronological observation of RAOECs on the PTFE-coated glass treated with the fibronectin, laminin, collagen or plasma was performed by using phase-contrast microscopy. RAOECs stably adhered, proliferated, and covered the PTFE surface within 3 days by treatment with fibronectin and laminin. The plasma and collagen also enhanced the cell adhesion to the PTFE surface, however most RAOECs were detached within 7 days. These results suggested that RAOECs unsteadily adhere to the PTFE synthetic graft implanted via blood molecules, the speed of endothelialization of the graft is delayed by the detachment of the endothelial cells from that. It was suggested that the treatment with the fibronectin and laminin suppress the thrombus of the PTFE synthetic graft implanted by both the rapid endothelialization caused by the stably adhesion of endothelial cells and the suppression of the platelets adhesion.å士(åŠè¡)麻åžå€§
Low immunogenicity of LNP allows repeated administrations of CRISPR-Cas9 mRNA into skeletal muscle in mice
çãžã¹ãããã£ãŒã®ã²ãã ç·šéæ²»çãç®æããLNP-mRNA茞éã·ã¹ãã ã®éçº. 京éœå€§åŠãã¬ã¹ãªãªãŒã¹. 2021-12-08.Nanotechnology for genome editing in multiple muscles simultaneously. 京éœå€§åŠãã¬ã¹ãªãªãŒã¹. 2021-12-08.Genome editing therapy for Duchenne muscular dystrophy (DMD) holds great promise, however, one major obstacle is delivery of the CRISPR-Cas9/sgRNA system to skeletal muscle tissues. In general, AAV vectors are used for in vivo delivery, but AAV injections cannot be repeated because of neutralization antibodies. Here we report a chemically defined lipid nanoparticle (LNP) system which is able to deliver Cas9 mRNA and sgRNA into skeletal muscle by repeated intramuscular injections. Although the expressions of Cas9 protein and sgRNA were transient, our LNP system could induce stable genomic exon skipping and restore dystrophin protein in a DMD mouse model that harbors a humanized exon sequence. Furthermore, administration of our LNP via limb perfusion method enables to target multiple muscle groups. The repeated administration and low immunogenicity of our LNP system are promising features for a delivery vehicle of CRISPR-Cas9 to treat skeletal muscle disorders
Extracellular nanovesicles for packaging of CRISPR-Cas9 protein and sgRNA to induce therapeutic exon skipping
Prolonged expression of the CRISPR-Cas9 nuclease and gRNA from viral vectors may cause off-target mutagenesis and immunogenicity. Thus, a transient delivery system is needed for therapeutic genome editing applications. Here, we develop an extracellular nanovesicle-based ribonucleoprotein delivery system named NanoMEDIC by utilizing two distinct homing mechanisms. Chemical induced dimerization recruits Cas9 protein into extracellular nanovesicles, and then a viral RNA packaging signal and two self-cleaving riboswitches tether and release sgRNA into nanovesicles. We demonstrate efficient genome editing in various hard-to-transfect cell types, including human induced pluripotent stem (iPS) cells, neurons, and myoblasts. NanoMEDIC also achieves over 90% exon skipping efficiencies in skeletal muscle cells derived from Duchenne muscular dystrophy (DMD) patient iPS cells. Finally, single intramuscular injection of NanoMEDIC induces permanent genomic exon skipping in a luciferase reporter mouse and in mdx mice, indicating its utility for in vivo genome editing therapy of DMD and beyond
Human Transcription Elongation Factor NELF: Identification of Novel Subunits and Reconstitution of the Functionally Active Complex
The multisubunit transcription elongation factor NELF (for negative elongation factor) acts together with DRB (5,6-dichloro-1-β-d-ribofuranosylbenzimidazole) sensitivity-inducing factor (DSIF)/human Spt4-Spt5 to cause transcriptional pausing of RNA polymerase II (RNAPII). NELF activity is associated with five polypeptides, A to E. NELF-A has sequence similarity to hepatitis delta antigen (HDAg), the viral protein that binds to and activates RNAPII, whereas NELF-E is an RNA-binding protein whose RNA-binding activity is critical for NELF function. To understand the interactions of DSIF, NELF, and RNAPII at a molecular level, we identified the B, C, and D proteins of human NELF. NELF-B is identical to COBRA1, recently reported to associate with the product of breast cancer susceptibility gene BRCA1. NELF-C and NELF-D are highly related or identical to the protein called TH1, of unknown function. NELF-B and NELF-C or NELF-D are integral subunits that bring NELF-A and NELF-E together, and coexpression of these four proteins in insect cells resulted in the reconstitution of functionally active NELF. Detailed analyses using mutated recombinant complexes indicated that the small region of NELF-A with similarity to HDAg is critical for RNAPII binding and for transcriptional pausing. This study defines several important protein-protein interactions and opens the way for understanding the mechanism of DSIF- and NELF-induced transcriptional pausing
Genetic and Phenotypic Characterization of a Rabies Virus Strain Isolated from a Dog in Tokyo, Japan in the 1940s
The rabies virus strain Komatsugawa (Koma), which was isolated from a dog in Tokyo in the 1940s before eradication of rabies in Japan in 1957, is known as the only existent Japanese field strain (street strain). Although this strain potentially provides a useful model to study rabies pathogenesis, little is known about its genetic and phenotypic properties. Notably, this strain underwent serial passages in rodents after isolation, indicating the possibility that it may have lost biological characteristics as a street strain. In this study, to evaluate the utility of the Koma strain for studying rabies pathogenesis, we examined the genetic properties and in vitro and in vivo phenotypes. Genome-wide genetic analyses showed that, consistent with previous findings from partial sequence analyses, the Koma strain is closely related to a Russian street strain within the Arctic-related phylogenetic clade. Phenotypic examinations in vitro revealed that the Koma strain and the representative street strains are less neurotropic than the laboratory strains. Examination by using a mouse model demonstrated that the Koma strain and the street strains are more neuroinvasive than the laboratory strains. These findings indicate that the Koma strain retains phenotypes similar to those of street strains, and is therefore useful for studying rabies pathogenesis
Effect of Annealing on Crystal and Local Structures of Doped Zirconia Using Experimental and Computational Methods
The effects of the annealing process
on the crystal and local structures
of doped zirconia were investigated by Rietveld refinements of synchrotron
X-ray and neutron diffraction, the maximum entropy method (MEM), X-ray
absorption spectroscopy (XAS), and first-principles calculations (FPCs).
This study reveals that the crystal structures of sintered and annealed
(Zr<sub>0.85</sub>Y<sub>0.15</sub>)ÂO<sub>2âÎŽ</sub> (8YSZ)
and (Zr<sub>0.81</sub>Sc<sub>0.18</sub>Ce<sub>0.01</sub>)ÂO<sub>2âÎŽ</sub> (10SSZ) are cubic with the space group <i>Fm</i>3Ì
<i>m</i> and have large atomic displacement parameters (<i>U</i><sub>iso</sub>). The amounts of tetragonal and other phases
are less than 0.2 mol % as estimated by comparison of the observed
and simulated X-ray diffraction patterns in the annealed zirconia.
For annealed 8YSZ, the <i>U</i><sub>iso</sub> values are
reduced, and the electrons around the Zr and oxide ion sites gather
at the center of each site. On the other hand, annealed 10SSZ shows
the opposite tendency as annealed 8YSZ. From the combined XAS and
FPC results, the distortion of the ZrO<sub>8</sub> polyhedra in zirconia
is related to the weakening of the two main peaks of the Zr K-edge,
while this distortion increases the strength of the Zr pre-edge. The
annealing process is found to enhance the periodic and local distortions
of the ZrO<sub>8</sub> polyhedra in 10SSZ. In contrast, the annealing
process for 8YSZ affects the local distortion of the ZrO<sub>8</sub> polyhedra but does not have an effect on the periodic disorder of
the crystal structure, as indicated by <i>U</i><sub>iso</sub> values and MEM analyses. We discuss the correlation among the degradation
of oxide ion conductivities by the annealing process and the crystal
and local structures of the doped zirconia using experimental and
computational methods