Use of the Fluorescent Staining Method for Determining the Viability of Mycobacterium lepraemurium

The cell suspension of Mycobacterium lepraemurium was exposed to heating of 40°C to 70°C for various lengths of time. The percent green-fluorescent cell by the midified fluorescein diacetate (FDA) -ethidium bromide (EB) staining method was calculated and compared with the infectivity to mice. The reduction in the percentage was associated significantly with the loss of the infectivity

A Phenotypic Analysis of Involucrin-Membrane-Bound Ovalbumin Mice after Adoptive Transfer of Ovalbumin-Specific CD8⁺ T Cells

To investigate the mechanism of autoimmunity and peripheral tolerance in the skin, several transgenic mouse strains expressing membrane-bound ovalbumin (mOVA) as an epidermal self-antigen under the control of keratinocyte-specific promotors, such as keratin 5 and keratin 14, were employed in combination with adoptive transfer of CD8⁺ T cells from OT-I mice (OT-I T cells) that recognize an ovalbumin-derived peptide. However, these strains showed bodyweight loss and required additional inflammatory stimuli, such as γ-irradiation and tape-stripping, to induce skin inflammation. In this study, we generated a mouse strain expressing mOVA under the control of human involucrin promoter (involucrin-mOVA mice). In contrast to previous strains, involucrin-mOVA mice spontaneously developed skin inflammation after the transfer of OT-I T cells in the absence of external stimuli without significant bodyweight loss. We focused on the skin infiltration process of OT-I T cells and found that transferred OT-I T cells accumulated around the hair follicles in the early phase of skin inflammation, and in the later phase, the skin inflammation spontaneously resolved despite the remaining OT-I T cells in the skin. Our involucrin-mOVA mice will provide a promising tool to investigate the pathogenesis and the tolerance mechanisms of cytotoxic skin autoimmunity

A cell-based high-throughput screening method to directly examine transthyretin amyloid fibril formation at neutral pH

Transthyretin (TTR) is a major amyloidogenic protein associated with hereditary (ATTRm) and nonhereditary (ATTRwt) intractable systemic transthyretin amyloidosis. The pathological mechanisms of ATTR-associated amyloid fibril formation are incompletely understood, and there is a need for identifying compounds that target ATTR. C-terminal TTR fragments are often present in amyloid-laden tissues of most patients with ATTR amyloidosis, and on the basis of in vitro studies, these fragments have been proposed to play important roles in amyloid formation. Here, we found that experimentally-formed aggregates of full-length TTR are cleaved into C-terminal fragments, which were also identified in patients' amyloid-laden tissues and in SH-SY5Y neuronal and U87MG glial cells. We observed that a 5-kDa C-terminal fragment of TTR, TTR81–127, is highly amyloidogenic in vitro, even at neutral pH. This fragment formed amyloid deposits and induced apoptosis and inflammatory gene expression also in cultured cells. Using the highly amyloidogenic TTR81–127 fragment, we developed a cell-based high-throughput screening method to discover compounds that disrupt TTR amyloid fibrils. Screening a library of 1280 off-patent drugs, we identified two candidate repositioning drugs, pyrvinium pamoate and apomorphine hydrochloride. Both drugs disrupted patient-derived TTR amyloid fibrils ex vivo, and pyrvinium pamoate also stabilized the tetrameric structure of TTR ex vivo in patient plasma. We conclude that our TTR81–127–based screening method is very useful for discovering therapeutic drugs that directly disrupt amyloid fibrils. We propose that repositioning pyrvinium pamoate and apomorphine hydrochloride as TTR amyloid-disrupting agents may enable evaluation of their clinical utility for managing ATTR amyloidosis

Indian Monsoonal Variations During the Past 80 Kyr Recorded in NGHP-02 Hole 19B, Western Bay of Bengal: Implications From Chemical and Mineral Properties

金沢大学理工研究域地球社会基盤学系Detailed reconstruction of Indian summer monsoons is necessary to better understand the late Quaternary climate history of the Bay of Bengal and Indian peninsula. We established a chronostratigraphy for a sediment core from Hole 19B in the western Bay of Bengal, extending to approximately 80 kyr BP and examined major and trace element compositions and clay mineral components of the sediments. Higher δ 18 O values, lower TiO 2 contents, and weaker weathering in the sediment source area during marine isotope stages (MIS) 2 and 4 compared to MIS 1, 3, and 5 are explained by increased Indian summer monsoonal precipitation and river discharge around the western Bay of Bengal. Clay mineral and chemical components indicate a felsic sediment source, suggesting the Precambrian gneissic complex of the eastern Indian peninsula as the dominant sediment source at this site since 80 kyr. Trace element ratios (Cr/Th, Th/Sc, Th/Co, La/Cr, and Eu/Eu*) indicate increased sediment contributions from mafic rocks during MIS 2 and 4. We interpret these results as reflecting the changing influences of the eastern and western branches of the Indian summer monsoon and a greater decrease in rainfall in the eastern and northeastern parts of the Indian peninsula than in the western part during MIS 2 and 4. © 2018. American Geophysical Union. All Rights Reserved

Sum rules of L-edge x-ray magnetic circularly polarized emission for 3d transition metals

We propose sum rules of x-ray magnetic circularly polarized emission (XMCPE) at L edges for 3d transition metals. By making use of combinations of incident and emitted photon helicities, z-component expectation values of spin, orbital, magnetic dipole, and quadrupole terms can be obtained separately. The fundamental difference in the sum rules between x-ray magnetic circular dichroism and XMCPE arises from the variety of electron transitions involving core states split by the spin-orbit interaction. The additional electron transition in XMCPE causes complicated angular dependence of the sum rule relation for the spin moment. Our findings promote future L-edge XMCPE measurements, which have not been observed at presen

Effects of conduction electron excitation on x-ray magnetic circularly polarized emission in itinerant ferromagnets

We develop a theoretical method to calculate x-ray magnetic circularly polarized emission (XMCPE) spectra for itinerant ferromagnets, in particular, Kα emission for transition metals. The effects of electron excitations in the d bands are treated by means of the Keldysh Green\u27s function. In our theoretical framework, the ferromagnetic ground state and the excitations are described by a mean-field approximation and a single-bubble diagram, respectively. We apply our method to Kα XMCPE spectra of metallic iron, and reproduce the observed tail structures on the low-energy side of each peak. Contributions from the excitations in the d bands depend strongly on the exchange interaction as well as the direct interaction between the 2p and 3d electrons. The dependence of the spectral intensity on emission angles with respect to the magnetization direction is cosinusoidal, indicating that Kα XMCPE can be used to investigate the magnetization directions in bulk ferromagnets

Theoretical calculation on x-ray magnetic circularly polarized emission for ferromagnetic 3d transition metals Fe, Co and Ni

In this study, we calculate x-ray magnetic circularly polarized emission (XMCPE) spectra at Kα transition for ferromagnetic 3d transition metals (TMs), specifically Fe(bcc), Ni(fcc), and Co(hcp). We obtain XMCPE spectra which agree well with the experiment for Fe. Electron excitations on the 3d bands affect significantly, moderately, and little the difference spectra for Fe, Co, and Ni, respectively. This difference arises from that in the number of d electron in unit cell, and the width of d bands.Asia-Pacific Conference on Condensed Matter Physics 202