幾何学的フラストレーション物質CuFeO_2_は磁場印加によってスピン誘導型強誘電相を含む多彩な磁気相が現れると同時に、各磁気相で三角格子の歪み方が異なるスピン・格子系でもあることから、自発格子変形を助長するような一軸圧力によって磁性・誘電性の同時制御を期待できる系である。今回、我々は磁場中で磁性・誘電性の一軸圧力応答を調べたところ、既知のスピン誘導型強誘電相とは異なる新奇強誘電磁気相が一軸圧力誘起することを見出し、温度・磁場・一軸圧力に関する磁気誘電相図を作成したので報告する。

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The plant hormone jasmonic acid (JA) has been recognized as a signal molecule that is produced in response to various stresses such as wounding and pathogen attack and that mediates defense reactions. We previously identified the JA-early responsive bHLH factor RERJ1 whose overexpression caused the up-regulation of many pathogenesis-related (PR) genes in rice cells and severe growth inhibition in rice plants. We reported in the last meeting that RERJ1 is induced by JA synthesized locally around the site of injury, and subsequently up-regulates the expressions of many PR genes and insect defense-related genes based on data obtained by histochemical analyses of RERJ1 promoter-GUS transgenic plants and characterization of the RERJ1 Tos17 mutant (rerj1-tos). Further investigations of the mutant revealed that JA-dependent inductive expressions of JAZ family genes, which encode important repressor proteins of JA signaling, were repressed in the rerj1-tos mutant after wounding. In a yeast two-hybridization assay we found interaction of RERJ1 with one of the rice JAZ proteins. In Arabidopsis it is known that the expression of JAZ genes is induced by bHLH factor MYC2 in a JA-dependent manner, and MYC2 activity is suppressed by interaction with JAZ proteins. Therefore we are investigating the interaction of RERJ1 with a rice MYC2 ortholog now, and will discuss roles of RERJ1 in rice JA signaling.

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Jasmonoyl-isoleucine (JA-Ile), which is biosynthesized by JAR, was reported to be a key molecule for COI1 mediated JA signaling pathway. In rice, it has been reported that OsJAR1 is involved in fertility and photomorphogenesis by characterizing rice osjar1 Tos17 mutant. However function of OsJAR1 in JA signaling pathway remains to be defined. In this study, we investigated some JA responsible phenotypes in osjar1 to understand the role of JA-Ile in rice. First we examined production of jasmonates. In wounded osjar1 leaves, accumulation of JA-Ile was severely repressed compared with wild-type rice, whereas accumulation of JA was comparable to wild-type rice. This suppression was complemented by expressing wild-type OsJAR1. These results strongly suggest that OsJAR1 is involved in JA-Ile biosynthesis in rice. Next we performed expression analysis of JA inducible genes in osjar1 mutant. The expressions of the induced monoterpenoid volatile linalool synthase gene, OsLS, the JA-induced bHLH type transcription factor gene, RERJ1, and JAZ genes after wounding or JA treatment were suppressed in osjar1. We further examined effects of JA and JA-Ile on accumulaton of phytoalexins in osjar1 leaves. JA-induced accumulation of phytoalexins seen in wild-type plant was not observed in osjar1 mutant. This suppression was recovered by JA-Ile treatment to osjar1. These results suggest that JA-Ile is essential for JA-induced gene expression and phytoalexins production.

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The relationship between the phases of a multi-phase steel and the machined surface defect characteristics & the chip separation mechanism is reported. Steels industrially supplied for machining applications are classified into three categories according to the phase. Five grades of steel representative of each were machined orthogonally with a carbide tool, JIS K10. The main conclusions are as follows. When the steel consists of precipitate carbides and a single phase matrix, the machined surface defects are micro-cutting tracks made by the WC particles of the tool and fine defects by fracture near the boundary between the precipitate carbides and the matrix of the steel. The surface roughness (Rz) is small, in the range of 2 or 3 μm. The chip is separated by micro-cutting. When the steel consists of multiple phases which are easily plastically deformable, the machined surface defects are large defects caused by fracture near the boundary between the phases. The surface roughness (Rz) is large, scores of μm. The chip separation is the result of fracture between the multiple phases. It was confirmed by review of previous documentation that the relationships described above should be widely applicable to multi-phase steels.

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掲載号:118巻7号,860-866頁
参考文献にしたがって5歳以上と5歳未満の2群に分けて解析せねばならないところを誤って7歳未満と7歳以上に分けて解析したため,上記論文を取り下げたい旨の申請が著者からあり,これを承認した.

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We encountered a very rare case of subcutaneous emphysema in the external auditory canal in a patient presenting with conductive hearing loss. The patient was a 11-year-old boy who had noticed narrowing of his left external auditory canal without pain since 7 months ago. About a month prior to his visit, he had also become aware of hearing loss in his left ear without apparent cause. Examination at a local clinic revealed swelling of the posterosuperior portion of the left external auditory canal and left conductive hearing loss, and the patient was referred to our hospital. On examination, the tympanic membrane on the left side was difficult to visualize because of stenosis of the external auditory canal. Pure-tone audiometry revealed conductive hearing loss of 55 dB in the speech frequency area in the left ear. CT imaging showed that the left external auditory canal was filled with an air bubble and had some bone defects in the posterosuperior portion. We diagnosed subcutaneous emphysema of the external auditory canal, cut the skin over the swollen area of the canal and then packed the canal with gauze impregnated with antibiotics for 1 week. The swelling of the left external auditory canal gradually decreased, resolving entirely by 4 months, with the hearing in the left ear also returning to the normal range. We speculated that the subcutaneous emphysema in the external auditory canal was caused by the rising middle ear pressure resulting from tubal dysfunction and the bone defects in the posterosuperior portion of the external auditory canal.

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It is essential for Japanese language learners to have sufficient skills to conduct casual conversations with native speakers to develop their language proficiency as well as their personal networks. The analysis of casual conversations in contact situations shows us the reaction to "iisashi" ―the suspended sentences or the sentence-ending ellipsis is one of the critical points for the smooth interactions and even a learner in advanced level needs practice to give proper reaction to it.

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Plant hormone jasmonic acid (JA) has been recognized as a signal molecule produced by various stresses such as wounding and pathogen attack and mediates defense reactions. We previously identified a JA-early responsive bHLH factor RERJ1, and reported that the RERJ1 overexpression showed up-regulations of many pathogenesis-related (PR) genes in rice cells and severe growth inhibition in the rice plants. However, biological function of the RERJ1 in rice plants is still unknown. We therefore conducted histochemical analyses of RERJ1 promoter-GUS transgenic plants, and characterized a Tos17 mutant of RERJ1 (rerj1-tos). The inductive expression of RERJ1 was observed in the defined area to be wounded within 2 hours, suggesting that RERJ1 functions at the sites injured by insect herbivory, for example. It has been known that JA is produced at narrow area in leaves by insect herbivory, which arrows plants to emit volatile terpenoids. Therefore, we examined expression of a monoterpene linalool synthetic gene OsLS in the rerj1-tos mutant and JA-deficient mutants. The OsLS gene, which maximally expresses at 2 to 4 hours after wounding in wild-type plants, was significantly less expressed in the rerj1-tos mutant, and also the expression was totally disappeared in the JA-deficient mutants. These results suggest that RERJ1 is induced by synthesized JA at injured sites, then functions to transactivate many PR genes, including the OsLS gene in rice plants.

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In this study, we investigated roles of JA in phytoalexin production using the JA-biosynthetic rice mutant cpm2 or the JA-Ile-biosynthetic rice mutant jar1. First we examined phytoalexin production in CuCl_2-treated mutant leaves. The production of the diterpenoid phytoalexins in cpm2 was comparable to that in a wild-type. On the other hand, the production of sakuranetin, a flavonoid phytoalexin, was suppressed in cpm2, and the suppression was restored by the addition of JA. Next, we examined phytoalexin production in Magnaphorthe oryzae infected leaf sheaths. Upon M. oryzae infection production of both diterpenoid phytoalexins and sakuranetin was severely suppressed in cpm2. These data suggest that, under CuCl_2 treatment, JA is essential for the production of sakuranetin, but not for diterpenoid phytoalexins. On the other hand, upon M. oryzae infection, JA is essential for production of both diterpenoid phytoalexins and sakuranetin. We also analyzed phenotypes of rice jar1 mutant defective in JA-Ile production to extend understanding of roles of jasmonates in phytoalexin production. We examined phytoalexin production by JA or JA-Ile treatment in jar1 leaves. Production of both diterpenoid phytoalexins and sakuranetin by JA treatment was suppressed in jar1. On the other hand, production of these phytoalexins by JA-Ile treatment in jarl was comparable to that in wild type. These data suggest that JA-Ile was essential for JA-induced phytoalexin production in rice.

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