Roles of peptide–peptide charge interaction and lipid phase separation in helix–helix association in lipid bilayer

AbstractThe roles of peptide–peptide charged interaction and lipid phase separation in helix–helix association in lipid bilayers were investigated using a model peptide, P24, as a transmembrane α-helical peptide, and its four analogues. Fluorescence amino acids, tryptophan (P24W) and pyrenylalanine (P24Pya), were introduced into the sequence of P24, respectively. Association of these peptides permits the resonance excitation energy transfer between tryptophan in P24W and pyrenylalanine in P24Pya or excimer formation between P24Pya themselves. To evaluate the effect of charged interaction on the association between α-helical transmembrane segments in membrane proteins, charged amino acids, glutamic acid (P24EW) and lysine (P24KPya), were introduced into P24W and P24Pya, respectively. Energy transfer experiments indicated that the charged interaction between the positive charge of lysine residue in P24KPya and the negative charge of glutamic acid residue in P24EW did not affect the aggregation of transmembrane peptides in lipid membranes. As the content ratio of sphingomyelin (SM) and cholesterol (Ch) was increased in the egg phosphatidylcholine (PC), the stronger excimer fluorescence spectra of P24Pya were observed, indicating that the co-existence of SM and Ch in PC liposomes, that is, the raft of SM and Ch, promotes the aggregation of the α-helical transmembrane peptides in lipid bilayers. Since the increase in the contents of SM and Ch leads to the decrease in the content of liquid crystalline-order phase, the moving area of transmembrane peptides might be limited in the liposomes, resulting in easy formation of the excimer in the presence of the lipid-raft

Characteristics of the Changes in the Compressive and Tensile Stress of the Construction Sealant under Cyclic Movement

A compact fatigue testing machine to quantitatively evaluate the effects of this complex degradation of sealants and the load change of the sealant under dynamic fatigue has been developed. The developed fatigue testing machine is compact with dimensions of (width) 100 × (length) 135 × (height) 110 mm. It can be installed in an outdoor exposure test site or in a chamber. Thus, this machine can be used for performing various compounded accelerated degradation tests. We report the use of this testing machine to examine the effects of this complex degradation of sealants and the load change of the sealant under dynamic fatigue

Induction and Enhancement of Cardiac Cell Differentiation from Mouse and Human Induced Pluripotent Stem Cells with Cyclosporin-A

Induced pluripotent stem cells (iPSCs) are novel stem cells derived from adult mouse and human tissues by reprogramming. Elucidation of mechanisms and exploration of efficient methods for their differentiation to functional cardiomyocytes are essential for developing cardiac cell models and future regenerative therapies. We previously established a novel mouse embryonic stem cell (ESC) and iPSC differentiation system in which cardiovascular cells can be systematically induced from Flk1+ common progenitor cells, and identified highly cardiogenic progenitors as Flk1+/CXCR4+/VE-cadherin− (FCV) cells. We have also reported that cyclosporin-A (CSA) drastically increases FCV progenitor and cardiomyocyte induction from mouse ESCs. Here, we combined these technologies and extended them to mouse and human iPSCs. Co-culture of purified mouse iPSC-derived Flk1+ cells with OP9 stroma cells induced cardiomyocyte differentiation whilst addition of CSA to Flk1+ cells dramatically increased both cardiomyocyte and FCV progenitor cell differentiation. Spontaneously beating colonies were obtained from human iPSCs by co-culture with END-2 visceral endoderm-like cells. Appearance of beating colonies from human iPSCs was increased approximately 4.3 times by addition of CSA at mesoderm stage. CSA-expanded human iPSC-derived cardiomyocytes showed various cardiac marker expressions, synchronized calcium transients, cardiomyocyte-like action potentials, pharmacological reactions, and ultra-structural features as cardiomyocytes. These results provide a technological basis to obtain functional cardiomyocytes from iPSCs

甲状腺刺激ホルモンシグナルは、BRAFV600E甲状腺癌マウスモデルにおけるゲノム不安定性を伴った高度悪性化に関与している

長崎大学学位論文 [学位記番号]博（医歯薬）甲第636号 [学位授与年月日]平成25年10月2

Sr Isotopic Composition of NIES Certified Reference Material No. 28 Urban Aerosols

An interlaboratory study of the National Institute for Environmental Studies (NIES) certified reference material (CRM) No. 28 Urban Aerosols collected from the filters of a central ventilating system in a building in the Beijing city center from 1996 to 2005 was performed to obtain an information value of the Sr isotopic composition. The Sr isotopic composition was measured using multi-collector-inductively coupled plasma-mass spectrometry (MC-ICP-MS) to confirm the CRM’s within- and between-bottle homogeneity, and the results showed a 87Sr/86Sr ratio of 0.710227 ± 0.000019 (2SD, n = 18). The Sr isotopic compositions were intercompared using thermal ionization mass spectrometry (TIMS), which showed good agreement with values obtained at NIES. Subsequently, a consistent 87Sr/86Sr ratio was observed between two dissolution (hotplate vs. high-pressure bomb) and Sr separation (Sr spec resin vs. cation exchange resin) methods. To validate and reproduce the accuracy of our analytical methods, the Sr isotopic compositions of secondary reference materials, JB-1b and JA-2, were also measured. Our results showed that NIES CRM No. 28 is appropriate for the quality control of Sr isotope measurements of particulate matter analyses for environmental and geochemical studies

Investigation by Imaging Mass Spectrometry of Biomarker Candidates for Aging in the Hair Cortex

BACKGROUND: Human hair is one of the essential components that define appearance and is a useful source of samples for non-invasive biomonitoring. We describe a novel application of imaging mass spectrometry (IMS) of hair biomolecules for advanced molecular characterization and a better understanding of hair aging. As a cosmetic and biomedical application, molecules whose levels in hair altered with aging were comprehensively investigated. METHODS: Human hair was collected from 15 young (20±5 years old) and 15 older (50±5 years old) volunteers. Matrix-free laser desorption/ionization IMS was used to visualize molecular distribution in the hair sections. Hair-specific ions displaying a significant difference in the intensities between the 2 age groups were extracted as candidate markers for aging. Tissue localization of the molecules and alterations in their levels in the cortex and medulla in the young and old groups were determined. RESULTS: Among the 31 molecules detected specifically in hair sections, 2--one at m/z 153.00, tentatively assigned to be dihydrouracil, and the other at m/z 207.04, identified to be 3,4-dihydroxymandelic acid (DHMA)--exhibited a higher signal intensity in the young group than in the old, and 1 molecule at m/z 164.00, presumed to be O-phosphoethanolamine, displayed a higher intensity in the old group. Among the 3, putative O-phosphoethanolamine showed a cortex-specific distribution. The 3 molecules in cortex presented the same pattern of alteration in signal intensity with aging, whereas those in medulla did not exhibit significant alteration. CONCLUSION: Three molecules whose levels in hair altered with age were extracted. While they are all possible markers for aging, putative dihydrouracil and DHMA, are also suspected to play a role in maintaining hair properties and could be targets for cosmetic supplementation. Mapping of ion localization in hair by IMS is a powerful method to extract biomolecules in specified regions and determine their tissue distribution

Prestate of Stress and Fault Behavior During the 2016 Kumamoto Earthquake (M7.3)

Fault behavior during an earthquake is controlled by the state of stress on the fault. Complex coseismic fault slip on large earthquake faults has recently been observed by dense seismic networks, which complicates strong motion evaluations for potential faults. Here we show the three‐dimensional prestress field related to the 2016 Kumamoto earthquake. The estimated stress field reveals a spatially variable state of stress that forced the fault to slip in a direction predicted by the “Wallace and Bott Hypothesis.” The stress field also exposes the pre‐condition of pore fluid pressure on the fault. Large coseismic slip occurred in the low‐pressure part of the fault. However, areas with highly pressured fluid also showed large displacement, indicating that the seismic moment of the earthquake was magnified by fluid pressure. These prerupture data could contribute to improved seismic hazard evaluations

Virulence assessment of six major pathogenic Candida species in the mouse model of invasive candidiasis caused by fungal translocation

Gastrointestinal colonization has been considered as the primary source of candidaemia; however, few established mouse models are available that mimic this infection route. We therefore developed a reproducible mouse model of invasive candidiasis initiated by fungal translocation and compared the virulence of six major pathogenic Candida species. The mice were fed a low-protein diet and then inoculated intragastrically with Candida cells. Oral antibiotics and cyclophosphamide were then administered to facilitate colonization and subsequent dissemination of Candida cells. Mice infected with Candida albicans and Candida tropicalis exhibited higher mortality than mice infected with the other four species. Among the less virulent species, stool titres of Candida glabrata and Candida parapsilosis were higher than those of Candida krusei and Candida guilliermondii. The fungal burdens of C. parapsilosis and C. krusei in the livers and kidneys were significantly greater than those of C. guilliermondii. Histopathologically, C. albicans demonstrated the highest pathogenicity to invade into gut mucosa and liver tissues causing marked necrosis. Overall, this model allowed analysis of the virulence traits of Candida strains in individual mice including colonization in the gut, penetration into intestinal mucosa, invasion into blood vessels, and the subsequent dissemination leading to lethal infections

注意障害事例の行動の特徴と機能評価との関連性：観察記録のテキストマイニングによる分析とTrail Making Test の検討より

研究報告Original Articles　本研究は，注意機能の評価として広く一般的に行われているTrail Making Test（TMT）の評価結果と，日常における行動の特徴との関連性を明らかにすることを目的とした探索的研究である．対象は，日本における医学論文情報のインターネット検索サービスである医中誌WEB に1999 年～2012 年までの13 年間に登録された文献のうち，“ 作業療法” と，“ 注意障害” をキーワードとして検索した（2013 年5 月検索）．その結果31 例の作業療法士が報告する症例を得たが，それらの内でTMT を評価として用いていた17 症例を対象とした．17 症例の報告から，34 組の行動の観察記録とTMT の評価結果を抽出し，行動の観察記録をテキストマイニング手法により分析した後，TMT の結果と照らし合わせて比較検討した．検討の結果，4 段階に分かれたTMT の遂行レベルについて，各々の段階の行動の特徴が明らかとなった．　The present exploratory study was aimed to examine the relationship between the results of the trail-making test (TMT), a common test to assess attentional function, and the behavioral characteristics in people with attentional deficits in daily life. A search of documents for a thirteen-year period, between 1999 and 2012, was conducted in May 2013, using Ichushi-Web, an Internet search service containing information on Japanese medical papers, with the keywords : “occupational therapy” and “attention deficits”. There were 31 papers written by occupational therapists, and 17 which adopted the TMT for assessment were selected. Observation records of the behaviors of 34 subjects and TMT assessment results were extracted from the 17 papers. The observation records were analyzed using text-mining, and the analysis results were compared with those of TMT assessment. The TMT assessment results were classified into four levels, and the characteristics of the behaviors at each level were identified