Coaggregation between Prevotella oris and Porphyromonas gingivalis

Background/PurposeThe coaggregation of bacteria has been defined as one of the most important processes in the oral infection such as periodontitis. Prevotella oris and Porphyromonas gingivalis, which are two of the periodontopathogens, are frequently detected in severe forms of periodontal diseases. However, the interaction between P. oris and P. gingivalis is still unknown. In this study, the coaggregation of P. oris with nine oral bacterial species including P. gingivalis was examined.MethodsAll bacteria used in this study were cultured anaerobically and suspended in coaggregation buffer. Each cell suspension was mixed in a test tube and subjected to shaking at room temperature for 1 hour. Subsequently, the coaggregation values were scored. Furthermore, the effects of various chemical reagents, and heat, proteinase K, and serum treatment were examined.ResultsIn this study, P. oris coaggregated only with P. gingivalis. A heat-stable, nonproteinous component of P. oris and a heat-labile, proteinous component of P. gingivalis play important roles in this coaggregation. In addition, this coaggregation was inhibited by l-arginine, l-lysine, and Nα-p-tosyl-l-lysine. Therefore, it was considered that a cell surface protein on P. gingivalis, such as gingipain, may be involved in the coaggregation. Furthermore, the coaggregation was not inhibited by serum treatment.ConclusionThis is the first report to describe the coaggregation of P. oris and P. gingivalis. Our study proposes the possibility that P. oris may promote the colonization of P. gingivalis in an early stage of biofilm formation. Furthermore, this coaggregation may contribute to the initiation and progression of periodontitis

Spin-Nematic and Spin-Density-Wave Orders in Spatially Anisotropic Frustrated Magnets in a Magnetic Field

We develop a microscopic theory of finite-temperature spin-nematic orderings in three-dimensional spatially anisotropic magnets consisting of weakly-coupled frustrated spin-1/2 chains with nearest-neighbor and next-nearest-neighbor couplings in a magnetic field. Combining a field theoretical technique with density-matrix renormalization group results, we complete finite-temperature phase diagrams in a wide magnetic-field range that possess spin-bond-nematic and incommensurate spin-density-wave ordered phases. The effects of a four-spin interaction are also studied. The relevance of our results to quasi-one-dimensional edge-shared cuprate magnets such as LiCuVO4 is discussed.Comment: 5 pages (2 column version), 4 figures, Revtex, published versio

Purification and characterization of hemolysin from Prevotella oris

AbstractWe observed hemolytic activity in culture supernatant of Prevotella oris. Results from growth-phase experiments show that hemolysin production increased during the logarithmic growth phase and decreased during the stationary phase. The hemolysin produced by P. oris was purified from the culture supernatant by ultrafiltration, diethylaminoethyl (DEAE) and carboxymethyl (CM) ion-exchange chromatography, and gel filtration chromatography; further, we investigated the purified hemolysin characteristics, including its ability to lyse human, horse, sheep, and rabbit erythrocytes. The purified hemolysin was observed as a single, 16-kDa band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gel. The specific activity was obtained by concentrating the purified hemolysin by 9200 fold. Although hemolysin was inactivated by heat treatment, ethylenediaminetetraacetic acid (EDTA), l-cysteine, dithiothreitol (DTT), and 2-mercaptoethanol enhanced its activity. Further, treatments using trypsin, MgCl2, CaCl2, and cholesterol did not affect its hemolytic activity. A pH of 6.0 was optimal for inducing the hemolysin activity. To the best of our knowledge, this is the first report describing the purification and characterization of hemolysin produced by P. oris

Prevotella oris溶血素の特徴とその赤血球膜との相互作用(The characteristics of Prevotella oris hemolysin and its interaction with the erythrocyte membrane)

P.orisはSDSポリアクリルアミドゲル電気泳動(SDS-PAGE)上で16kDaバンドとして観察される蛋白質溶血素を産生する。P.oris溶血素のN末端アミノ酸配列を分析した。7N末端アミノ酸を特定し、P.oris溶血素が短鎖ペプチド配列を有すると推定した。溶血素のアミノ酸配列は他の細菌性蛋白やペプチドと共通の配列ではなかった。P.oris溶血素は溶血前に温度依存性に赤血球と結合することが明らかになった。この溶血活性は赤血球をトリプシンまたはグリコシダーゼで処理した場合に阻害された。コレステロールは活性には影響しなかった。トリプシン処理した赤血球膜の特徴からSDS-PAGEにおいて46kDa糖蛋白が消失した。以上より、46kDa赤血球膜糖蛋白は溶血素の結合部位であることが示唆された。本研究はP.oris溶血素のN末端アミノ酸配列とその赤血球膜上の結合部位に関する初めての報告である。P.orisはSDSポリアクリルアミドゲル電気泳動(SDS-PAGE)上で16kDaバンドとして観察される蛋白質溶血素を産生する。P.oris溶血素のN末端アミノ酸配列を分析した。7N末端アミノ酸を特定し、P.oris溶血素が短鎖ペプチド配列を有すると推定した。溶血素のアミノ酸配列は他の細菌性蛋白やペプチドと共通の配列ではなかった。P.oris溶血素は溶血前に温度依存性に赤血球と結合することが明らかになった。この溶血活性は赤血球をトリプシンまたはグリコシダーゼで処理した場合に阻害された。コレステロールは活性には影響しなかった。トリプシン処理した赤血球膜の特徴からSDS-PAGEにおいて46kDa糖蛋白が消失した。以上より、46kDa赤血球膜糖蛋白は溶血素の結合部位であることが示唆された。本研究はP.oris溶血素のN末端アミノ酸配列とその赤血球膜上の結合部位に関する初めての報告である

Field and temperature dependence of the NMR relaxation rate in the magnetic quadrupolar liquid phase of spin-1/2 frustrated ferromagnetic chains

It is generally difficult to experimentally distinguish magnetic multipolar orders in spin systems. Recently, it was proposed that the temperature dependence of the nuclear magnetic resonance relaxation rate 1/T_1 can involve an indirect, but clear signature of the field-induced spin nematic or multipolar Tomonaga-Luttinger (TL) liquid phase [Phys. Rev. B79, 060406(R) (2009)]. In this paper, we evaluate accurately the field and temperature dependence of 1/T_1 in spin-1/2 frustrated J1-J2 chains combining field-theoretical techniques with numerical data. Our results demonstrate that isotherms of 1/T_1 as a function of magnetic field also exhibit distinctive non-monotonic behavior in spin nematic TL liquid, in contrast with the standard TL liquid in the spin-1/2 Heisenberg chain. The relevance of our results to quasi one-dimensional edge-sharing cuprate magnets, such as LiCuVO4, is discussed.Comment: 11 pages (2 column), 5 figures, published versio

抗CD8モノクローナル抗体VH領域の解析

We analyzed the nucleotide sequence of immunoglobulin (Ig) heavy chain variable regions (VH) of seven hybridomas which produce anti-CD8 monoclonal antibodies. These seven antibodies were classified into four groups according to the results of a cell binding inhibition assay. The assay also indicated that CD8 antigen expressed at least four different epitopes. The VH nucleotide sequences were classified in three families. Three clones belonged to VH subgroup I(B), and two to VH subgroup V(A). Sequences in members of each family showed identical V-D-J recombinations, suggesting that the clones of each family arose from common ancestral clones. Some somatic mutations were observed in both the framework segments and the complementarity determining regions (CDR) of the I(B) clones, and only one amino acid substitution was observed. Two clones of the V(A) subgroup possessed an identical VH sequence. Although the clones of each family had originated from single ancestral clones, reactivity within families with CD8 antigen was found to vary widely. At the same time, two clones derived from different fusions, on the basis of their equal reactivities with CD8, were classified into subgroup II(A) ; subsequently, they were shown to share the same V-D-J combination. The speeds of reaction of the antibodies with CD8 antigen were investigated by flow cytometry. The observed rates of increase of brightness and final saturated brightness with these antibodies were quite different. Those results indicated that somatic mutations occurring in the VH gene of the anti-CD8 antibodies cause differences in their affinity with epitopes. Two separately originated clones that were induced by the same CD8 antigen showed identical paratopes and VH usage

NMR relaxation rate in the field-induced octupolar liquid phase of spin-1/2 J1-J2 frustrated chains

In the spin-1/2 frustrated chain with nearest-neighbor ferromagnetic exchange J1 and next-nearest-neighbor antiferromagnetic exchange J2 under magnetic field, magnetic multipolar-liquid (quadrupolar, octupolar, and hexadecapolar) phases are widely expanded from the saturation down to a low-field regime. Recently, we have clarified characteristic temperature and field dependence of the NMR relaxation rate 1/T_1 in the quadrupolar phase. In this paper, we examine those of 1/T_1 in the octupolar phase combining field theoretical method with numerical data. The relevance of the results to quasi one-dimensional J1-J2 magnets such as PbCuSO4(OH)2, Rb2Cu2Mo3O12 and Li2ZrCuO4 is shortly discussed.Comment: 6 pages (1 column), 3 figure

How Does Culture Appear in Interviews?: Focus on "Treating" in Korea and "Going Dutch" in Japan

研究ノー

Correlation between fabrication factor and superconducting properties of the Tl-and-Bi-based high-Tc superconductor

Large critical current densities (J(sub c)) were obtained in c axis oriented Tl-1 223/Ag composite tapes fabricated by spraying methods without a vacuum. Transport measurements at 77K under a zero field indicated a J(sub c) of 9 x 10(exp 4) A/sq cm and 7 x 10(exp 3) A/sq cm at 1T for the tapes fabricated by spray pyrolysis. The novel GPM method was also applied for Bi-2212/Ag PIT composite wire, and found to be very effective for improving the distribution of voids, which caused from the melt-solidifying process. The GPM showed a marked effect for obtaining homogeneous long wire. A 1 T class coil was successfully fabricated with monocore wire