Hardness Change of Ferrous Martensite by Deformation

A series of Fe-Ni-C martensites having transformation twins and an Fe-Cr-Ni-C martensite not having transformation twins but dislocations were rolled at 200°C, room temperature and liquid nitrogen temperature. The hardness change and the deformation mode of the martensite were examined. The twinned martensites were deformed by slip, when the carbon content of the martensite was low or the deformation temperature was high. In this case, the hardness change with reduction of deformation showed usual strain-hardening. However, when the carbon content was high or the deformation temperature was low, the martensite was deformed by twinning. In this case, the martensite showed strain-softening at a small percent of reduction, and then it was strain-hardened rapidly beyond the minimum hardness with increase in reduction. The untwinned martensite was deformed by slip, and the hardness change with reduction showed a usual strain-hardening curve

ボツリヌス ドクソ フクゴウタイ ノ コウゾウ ト キノウ

ボツリヌス神経毒素(BoNT)は,自然界最強の毒素であり,コリン作動性シナプスからの神経伝達物質放出の阻害によって,ヒトや動物のボツリヌス症として知られる致死的な疾病を引き起こす。ボツリヌス菌株は,BoNT の抗原性の違いにより,A から G 型の血清型に分類され,A,B,E および F 型はヒトに対して,一方 C および D 型は動物や鳥類のボツリヌス症の原因物質とされている。全ての血清型の BoNT には各々の無毒成分タンパク質が非共有結合的に会合して大きな毒素複合体(TC)を形成する。培養液中では,BoNT と非毒非血球凝集素(NTNHA)の複合体(M-TC)とさらに M-TC に 3 種の血球凝集素(HA;HA-70,HA-33 および HA-17)が会合したより大きな複合体(L-TC)が存在する。これらの TC には,構成成分のいくつかには特定の部位には分子内切断(nick)があるため,SDS-PAGE 上で多数のバンドが出現する。C および D 型のボツリヌス菌株から毒素の精製中に著者らは偶然にも無傷の TC 種を産生する特異的な D 型菌 4947 株(D-4947)を見出した。 本論文では,主に特異的 D-4947 の TC に関する主要な知見が述べられている。(1)C および D 型TC 構成成分(BoNT,NTNHA および HA-70)における菌体プロテアーゼあるいは自発的切断によるニック部位が特定された。(2)分離精製した各 TC 構成成分による L-TC の再構成に成功し,その形成機構を明らかにし,各構成成分遺伝子の発現が調べられた。(3)各種培養細胞系を用いて,C および D 型 L-TC の HA-33 が小腸内皮細胞透過において本質的な役割を果たしていた。(4)電顕観察および HA-33/HA-17 複合体の X 線結晶解析により,個々のサブユニットが会合する経路と 14 量体からなる L-TC 各サブユニットの立体的配置を初めて提唱した。(5)消化酵素耐性実験から,NTNHA が BoNT を消化から保護している決定的な証拠を提供した。また,NTNHA 分子は 1 個の亜鉛分子を含み,BoNT との構造的類似性が認められ,X 線小角散乱分析から NTNHA の水溶液中での動的構造の性質が示された。Botulinum neurotoxins (BoNTs) are the most potent toxins known in nature, causing the lethal disease known as botulism in human and animals. The BoNTs act by inhibiting neurotransmitter release from cholinergic synapses. Accidental botulism often occurs through ingestion of Clostridium botulinum contaminated food. Different strains of C. botulinum produce seven distinct serotypes of BoNTs, classified A through G. Serotypes A, B, E and F in human botulism, whereas C and D appear to be causative toxins for animal and avian botulism. All serotypes of BoNT associate non-covalently with auxiliary nontoxic proteins, thereby forming large toxin complexes (TCs), M-TC (BoNT/NANHA) and L-TC (BoNT/NTNHA/HA-70/HA-33/HA-17) in the culture medium. The formation of TCs appear not only to protect BoNTs from the hostile environment of the digestive tract but also to assist neurotoxin translocation across the intestinal mucosal layer. However, BoNT, NTNHA and HA-70 components of the TC are nicked at specific sites by a bacterial protease, leading to the appearance of many fragments on SDS-PAGE. Fortunately, the author and collaborators serendipitously found unique serotype D strain 4947 (D-4947) which produces intact M-TC and L-TC without any nicking. In this manuscript, five topics on mainly D-4947 TC studies provided by the author and collaborators are described: (1) Specific nicking sites in the components of the serotype C and D TCs were characterized, including dichain structure in BoNT, spontaneous nicking in the NTNHA and endogenous cleavage in HA-70. (2) In vitro reconstitution of functional HAs of serotype C, and D-4947 L-TC assembly mechanism was achieved by the mixing of individual components, which was indistinguishable with native L-TC. Then the gene expressions of five individual D-4947 L-TC components were examined by quantitative reverse transcriptase PCR. (3) The HA-33 component of the serotypes C and D TCs played a critical role in the binding and transcytosis in intestinal epithelium, and other HA components protecting BoNT against gastrointestinal digestion, using various culture cells including Caco-2 cells, rat small intestinal epithelial cells, bovine aortic endothelial cells and equine erythrocytes. (4) A novel 14-mer subunit structure model of D-4947 L-TC was proposed on the basis of the negative stain transmission electron microscopy and X-ray crystal structure of the complex formed by two HA-33 plus one HA-17. (5) Definitive evidence was provided that both recombinant and native NTNHAs play a crucial role in protecting BoNT from proteolysis by digestive enzymes. Every single NTNHA contained a single Zn atom, of which small-angle X-ray scattering analysis of the NTNHA revealed the structural dynamics

<ORIGINAL>Quantification of Porphyromonas gingivalis by real time PCR : new primers targeting the rgpA and rgpB gene encoding RGP

We designed new primers for the quantification of Porphyromonas gingivalis by real time PCR. The new primer set targeted the rgpA and rgpB genes that encode arginine specific cysteine proteinase (Arggingipain or Rgp), one of the putative pathogenic factors of P. gingivalis. The PCR product obtained using our primers showed no by-products by melting curve analysis. The PCR product sequence showed no significant matches to other sequences by BLAST searching of genetic databases except for matches to P. gingivalis rgpA and rgpB sequence, and could not be amplified from template derived from other oral bacteria apart from P. gingivalis. Therefore, we concluded that our primers were specific for P. gingivalis rgpA and rgpB, and could be used to quantity from 10^3 to 10^7 P. gingivalis cells when applied to real time PCR

Detection of Polarized Broad Emission in the Seyfert 2 Galaxy Mrk 573

We report the discovery of the scattered emission from a hidden broad-line region (BLR) in a Seyfert 2 galaxy, Mrk 573, based on our recent spectropolarimetric observation performed at the Subaru Telescope. This object has been regarded as a type 2 AGN without a hidden BLR by the previous observations. However, our high quality spectrum of the polarized flux of Mrk 573 shows prominent broad (~3000 km/s) H_alpha emission, broad weak H_beta emission, and subtle Fe II multiplet emission. Our new detection of these indications for the presence of the hidden BLR in the nucleus of Mrk 573 is thought to be owing to the high signal-to-noise ratio of our data, but the possibility of a time variation of the scattered BLR emission is also mentioned. Some diagnostic quantities such as the IRAS color, the radio power, and the line ratio of the emission from the narrow-line region of Mrk 573 are consistent with the distributions of such quantities of type 2 AGNs with a hidden BLR. Mrk 573 is thought to be an object whose level of the AGN activity is the weakest among the type 2 AGNs with a hidden BLR. In terms of the systematic differences between the type 2 AGNs with and without a hidden BLR, we briefly comment on an interesting Seyfert 2 galaxy, Mrk 266SW, which may possess a hidden BLR but has been treated as a type 2 AGNs without a hidden BLR.Comment: 9 pages including 6 figures, to appear in The Astronomical Journa

In Vitro Reconstitution of the Clostridium botulinum Type D Progenitor Toxin

Clostiridium botulinum D型4947株は蛋白分解作用を受けない完全型として、異なったサイズの2種類のプロジェニター毒素（MとL）を産生する。M毒素は神経毒素（NT）と非毒素系ー非血球凝集素（NTNHA）で構成されているのに対し、L毒素はM毒素と血球凝集素（HA-70、HA-17、HA-33）によって構成されている。HA-70サブコンポーネントとHA-33/17混合体は変成剤の存在下でクロマトグラフィーによりL毒素からほぼ単一の形で得られた。著者らは、純化したM毒素、HA-70とHA-33/17を混合してL毒素を再構成することに初めて成功した。再構成したL毒素とネイティブのL毒素はゲル濾過、PAGEプロファイル、血球凝集活性、赤血球への吸着活性、マウスへの経口毒力などの諸症状が全く同じであった。トリプシン処理によりニックを持つNTNHAで構成されたM毒素はHAサブコンポーネントと一緒にしてもL毒素を再構成することが出来なかったのに対し、プロテアーゼ処理したL毒素はM毒素とHAサブコンポーネントに隔離することが出来なかった。これらの結果から、著者らはM毒素が最初にNTとNTNHAの会合により形成され、その後HA-70とHA-33/17の会合によってL毒素へ変換されると結論ずけた

Effect of connective tissue growth factor (CCN2/CTGF) on proliferation and differentiation of mouse periodontal ligament-derived cells

Background: CCN2/CTGF is known to be involved in tooth germ development and periodontal tissue remodeling, as well as in mesenchymal tissue development and regeneration. In this present study, we investigated the roles of CCN2/CTGF in the proliferation and differentiation of periodontal ligament cells (murine periodontal ligament-derived cell line: MPL) in vitro. Results: In cell cultures of MPL, the mRNA expression of the CCN2/CTGF gene was stronger in sparse cultures than in confluent ones and was significantly enhanced by TGF-β. The addition of Recombinant CCN2/CTGF (rCCN2) to MPL cultures stimulated DNA synthesis and cell growth in a dose-dependent manner. Moreover, rCCN2 addition also enhanced the mRNA expression of alkaline phosphatase (ALPase), type I collagen, and periostin, the latter of which is considered to be a specific marker of the periosteum and periodontium; whereas it showed little effect on the mRNA expression of typical osteoblastic markers, e.g., osteopontin and osteocalcin. Finally, rCCN2/CTGF also stimulated ALPase activity and collagen synthesis. Conclusion: These results taken together suggest important roles of CCN2/CTGF in the development and regeneration of periodontal tissue including the periodontal ligament.</p

SDSSp J104433.04−-012502.2 at z=5.74z=5.74 is Gravitationally Magnified by an Intervening Galaxy

During the course of our optical deep survey program on L$\alpha$ emitters at $z \approx 5.7$ in the sky area surrounding the quasar SDSSp J104433.04$-$012502.2 at $z=5.74$, we found that a faint galaxy with $m_B$(AB) $\approx 25$ is located at \timeform{1".9} southwest of the quasar. Its broad-band color properties from $B$ to $z^\prime$ suggest that the galaxy is located at a redshift of $z \sim 1.5$ -- 2.5. This is consistent with no strong emission line in our optical spectroscopy. Since the counter image of the quasar cannot be seen in our deep optical images, the magnification factor seems not to be very high. Our modest estimate is that this quasar is gravitationally magnified by a factor of 2.Comment: 11 pages, 5 figures, PASJ, in pres

Spontaneous Nicking in the Nontoxic-Nonhemagglutinin Component of the costridium botulinum Toxin Conplex

Clostiridium botulinum D型4947株によって産生された毒素複合体から非毒素ー非血球凝集素（NTNHA）標品を蛋白分解酵素フリーの条件下で、単独の形と神経毒(NT)/NTNHA複合体の形で調製できた。両調製物質のNTNHAはスポンテニアスにニックの入ったNTNHAとなり、15-と115-kDaフラグメント及び特異的部分でいくつかのアミノ酸の削除を生じることが長時間培養のSDS-PAGEで認められた。しかし、NT/NTNHA/血球凝集素(HA)複合体は同じ条件下でニックの入らない一本鎖のペプチドのままであった。NTNHA調製物に少量のニック型の物が含まれていることから、NTNHAのニック型は精製の残物と/あるいはNTNHAがインタクトNTNHAをそれ自身との切断酵素活性によってニックを入れたことが考えられる