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Search Results: 1 - 10 of 8225 matches for " Chieko Kai "
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Selective Translation of the Measles Virus Nucleocapsid mRNA by La Protein
Chieko Kai
Frontiers in Microbiology , 2011, DOI: 10.3389/fmicb.2011.00173
Abstract: Measles, caused by measles virus (MeV) infection, is the leading cause of death in children because of secondary infections attributable to MeV-induced immune suppression. Recently, we have shown that wild-type MeVs induce the suppression of protein synthesis in host cells (referred to as “shutoff”) and that viral mRNAs are preferentially translated under shutoff conditions in infected cells. To determine the mechanism behind the preferential translation of viral mRNA, we focused on the 5′ untranslated region (UTR) of nucleocapsid (N) mRNA. The La/SSB autoantigen (La) was found to specifically bind to an N-5′UTR probe. Recombinant La enhanced the translation of luciferase mRNA containing the N-5′UTR (N-fLuc), and RNA interference of La suppressed N-fLuc translation. Furthermore, recombinant MeV lacking the La-binding motif in the N-5′UTR displayed delayed viral protein synthesis and growth kinetics at an early phase of infection. These results suggest that La induced predominant translation of N mRNA via binding to its 5′UTR under shutoff conditions. This is the first report on a cellular factor that specifically regulates paramyxovirus mRNA translation.
Evaluation of a Recombinant Measles Virus as the Expression Vector of Hepatitis C Virus Envelope Proteins  [PDF]
Yuri Kasama, Masaaki Satoh, Makoto Saito, Seiji Okada, Chieko Kai, Kyoko Tsukiyama-Kohara
World Journal of Vaccines (WJV) , 2011, DOI: 10.4236/wjv.2011.13010
Abstract: Measles virus (MV) is a negative strand RNA virus of the family Paramyxoviridae, and the attenuated Edmonston-B strain can be engineered by the reverse genetics system. Here we constructed the recombinant Edmonston strain of measles virus (MV-Ed) that expressed hepatitis C virus (HCV) envelope proteins (rMV-E1E2). The rMV-E1E2 successfully expressed HCV E1 and E2 proteins. To evaluate its immunogenicity, NOD/Scid/Jak3null mice that were engrafted with human peripheral blood mononuclear cells (huPBMC-NOJ) were infected with this rMV-E1E2. Although human lymphocytes could be isolated from the spleens of mock-infected mice during the 2-weeks-long experiment, the proportion of mice that were infected with MV or rMV-E1E2 was decreased in a viral dose-dependent manner. Over 103 PFU of virus infection decreased the human PBL to less than 5%. Significant decrease of B cell population in human PBL from rMV-E1E2 infected NOD-SCID mice and decrease of T cell population in those from MV infected mice were observed. Human antibody production in these mice was also examined. Thus, the results in this study may contribute for future improvement of recombinant vaccine using measles virus vector.
Simulation of a Daily Precipitation Time Series Using a Stochastic Model with Filtering  [PDF]
Chieko Gomi, Yasuhisa Kuzuha
Open Journal of Modern Hydrology (OJMH) , 2013, DOI: 10.4236/ojmh.2013.34025
Abstract: After we modified raw data for anomalies, we conducted spectral analysis using the data. In the frequency, the spectrum is best described by a decaying exponential function. For this reason, stochastic models characterized by a spectrum attenuated according to a power law cannot be used to model precipitation anomaly. We introduced a new model, the e-model, which properly reproduces the spectrum of the precipitation anomaly. After using the data to infer the parameter values of the e-model, we used the e-model to generate synthetic daily precipitation time series. Comparison with recorded data shows a good agreement. This e-model resembles fractional Brown motion (fBm)/fractional Lévy motion (fLm), especially the spectral method. That is, we transform white noise Xt to the precipitation daily time series. Our analyses show that the frequency of extreme precipitation events is best described by a Lévy law and cannot be accounted with a Gaussian distribution.
Complete Genome Sequence of Rothia mucilaginosa DY-18: A Clinical Isolate with Dense Meshwork-Like Structures from a Persistent Apical Periodontitis Lesion
Kazuyoshi Yamane,Takayuki Nambu,Takeshi Yamanaka,Chiho Mashimo,Chieko Sugimori,Kai-Poon Leung,Hisanori Fukushima
Sequencing , 2010, DOI: 10.1155/2010/457236
Abstract: Rothia mucilaginosa is an opportunistic pathogen in the human oral cavity and pharynx. We found that R. mucilaginosa DY-18, a clinical isolate from a persistent apical periodontitis lesion, had biofilm-like structures. Similar structures were also observed on R. mucilaginosa ATCC25296. To further study these structures, we determined the complete genome sequence of DY-18 and found it a 2.26-Mb chromosome. Regarding stress responsive systems known to affect biofilm formation in many bacteria, DY-18 genome possessed only two sigma factor genes. One of these encoded an additional sigma factor whose promoter-binding activity may be regulated in response to environmental stimuli. Additionally, several genes assigned to two-component signal transduction systems were presented in this genome. To the best of our knowledge, this is the first complete genome of R. mucilaginosa species and our data raise the possibility that this organism regulates the biofilm phenotype through these stress responsive systems.
Leukemogenic Fusion Gene (p190 BCR-ABL) Transduction into Hematopoietic Stem/Progenitor Cells in the Common Marmoset  [PDF]
Yan Dong, Seiichiro Kobayashi, Yamin Tian, Manabu Ozawa, Takafumi Hiramoto, Kiyoko Izawa, Yuansong Bai, Yasushi Soda, Erika Sasaki, Toshio Itoh, Yoshiro Maru, Naoki Oyaizu, Arinobu Tojo, Chieko Kai, Kenzaburo Tani, Satoshi Takahashi, Kaoru Uchimaru
Open Journal of Blood Diseases (OJBD) , 2012, DOI: 10.4236/ojbd.2012.21001
Abstract: Patients with Philadelphia chromosome (p190 BCR-ABL fusion gene)-positive acute lymphoblastic leukemia have a poor prognosis despite intensive therapeutic intervention.In this study, we attempted to develop a leukemia nonhuman primate model that mimics various human systems. Hematopoietic stem/progenitor cells in the common marmoset were transduced with a lentiviral vector containing the p190 BCR-ABL fusion gene by ex vivo transduction or in vivo direct bone marrow injection. In the latter model, BCR-ABL gene expression was maintained for more than one and a half years. One marmoset unexpectedly developed myelofibrosis-like disease. However, none of the marmosets have developed leukemia to date. In conclusion, we successfully achieved sustained p190 BCR-ABL gene expression in vivo. However, a genetic mutation in addition to p190 BCR-ABL may be required for the malignant transformation of hematopoietic stem/progenitor cells in the common marmoset during the short observation period. This novel in vivo approach will help develop a marmoset leukemia model in the future.
Study on Properties of Silver Powder for Maki-e  [PDF]
Chieko Narita, Yutaro Shimode, Kazushi Yamada
Materials Sciences and Applications (MSA) , 2015, DOI: 10.4236/msa.2015.61001
Abstract: Maki-e is a traditional Japanese decorative technique that uses the natural lacquer Urushi and metal powders. In 2014, there exist only two companies that manufacture silver powder for the purpose of Maki-e, and this study focuses on comparing the powders manufactured by them. Gloss and color of each silver powder were measured after Maki-e decoration was finished, and EDS (energy-dispersive X-ray spectroscopy) was used to determine the differences in their chemical composition. In addition, to verify the effect of polishing, residual gloss after sulfuration and polishing was measured. The study revealed that the shapes of the silver powders (Maru-fun, No. 1) manufactured by the two companies are different and it affects the occupancy rate of Urushi and powder, which in turn affects their gloss and color. Wakou silver has a very strong resistance to sulfuration; however, owing to its Pd content, its chroma is much lower than that of other powders. It was shown that sulfuration on powder surface can be removed by polishing irrespective of the shape and chemical composition ratio of the particles.
Study on Characteristics of Gold Powder with Round Shape for Maki-e  [PDF]
Chieko Narita, Yutaro Shimode, Kazushi Yamada
Materials Sciences and Applications (MSA) , 2015, DOI: 10.4236/msa.2015.610086
Abstract: Maki-e is a traditional Japanese decorative technique that uses the natural lacquer Urushi and metal powders. Currently, there exist only two companies that manufacture metal powder for the purpose of Maki-e, and this research focuses on comparing the material characteristics of the gold powders with round shape manufactured by them. EDS (energy-dispersive X-ray spectroscopy) analysis, image analysis of particle shape before and after Maki-e processing, and color analysis of samples after Maki-e processing were carried out in this research. The study revealed that current gold powders with round shape had almost the same content ratio regardless of the manufacturing company and the powder diameter. In addition, spherical shape and irregular shape were observed in any gold powders, and the aggregates were observed in powder with increasing the powder diameter, while the shape of the aggregates differed with manufacturing companies. Therefore, it was indicated that the aggregates in the powder made by Asano Co., Ltd. had an influence on the particle diameter and its deviation after Maki-e processing. Moreover, the powder in Urushi resin has an influence on the Maki-e appearance because there is a color difference in polished powder, powder in Urushi resin, and Urushi resin.
Color Barrier Free Displays in Disaster Situations  [PDF]
Kensei Tsuchida, Chieko Kato, Toshiaki Nagshima
Open Journal of Social Sciences (JSS) , 2016, DOI: 10.4236/jss.2016.42005
Abstract:

Concerning color barrier free, there have been many research studies and an increasing interest in it. For example, to expand activities for the promotion of colorblind-friendly designs not only among scientists but also among industrial products and public facilities, the non-profit organization CUDO (Color Universal Design Organization) was established in 2004. However, there has been very little research of this type focusing on disaster situations. From their experiences volunteering in reconstruction support for victims of the 2011 tsunami, the authors came to recognize the importance for both non-colorblind and colorblind people to notice and distinguish emergency escape notifications, cautions and passage maps quickly and accurately. Therefore this research is aimed at the realization of color barrier free displays in disaster situations. Initially, requirements for color barrier free displays in disaster situations were analyzed. Four desirable criteria were derived as a result: “eye-catching”, “instantly-readable”, “unmistakable” and “stable”. In order to evaluate given signs from the viewpoint of the above criteria, evaluation experiment systems for displays in disaster situations were developed. With the evaluation experiment systems it would be possible to design effective signs and maps as color barrier free displays in disaster situations.

The Nonstructural Proteins of Nipah Virus Play a Key Role in Pathogenicity in Experimentally Infected Animals
Misako Yoneda,Vanessa Guillaume,Hiroki Sato,Kentaro Fujita,Marie-Claude Georges-Courbot,Fusako Ikeda,Mio Omi,Yuri Muto-Terao,T. Fabian Wild,Chieko Kai
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0012709
Abstract: Nipah virus (NiV) P gene encodes P protein and three accessory proteins (V, C and W). It has been reported that all four P gene products have IFN antagonist activity when the proteins were transiently expressed. However, the role of those accessory proteins in natural infection with NiV remains unknown. We generated recombinant NiVs lacking V, C or W protein, rNiV(V?), rNiV(C?), and rNiV(W?), respectively, to analyze the functions of these proteins in infected cells and the implications in in vivo pathogenicity. All the recombinants grew well in cell culture, although the maximum titers of rNiV(V?) and rNiV(C?) were lower than the other recombinants. The rNiV(V?), rNiV(C?) and rNiV(W?) suppressed the IFN response as well as the parental rNiV, thereby indicating that the lack of each accessory protein does not significantly affect the inhibition of IFN signaling in infected cells. In experimentally infected golden hamsters, rNiV(V?) and rNiV(C?) but not the rNiV(W?) virus showed a significant reduction in virulence. These results suggest that V and C proteins play key roles in NiV pathogenicity, and the roles are independent of their IFN-antagonist activity. This is the first report that identifies the molecular determinants of NiV in pathogenicity in vivo.
Comparison of the virulence of exopolysaccharide-producing Prevotella intermedia to exopolysaccharide non-producing periodontopathic organisms
Takeshi Yamanaka, Kazuyoshi Yamane, Tomoyo Furukawa, Chiho Matsumoto-Mashimo, Chieko Sugimori, Takayuki Nambu, Noboru Obata, Clay B Walker, Kai-Poon Leung, Hisanori Fukushima
BMC Infectious Diseases , 2011, DOI: 10.1186/1471-2334-11-228
Abstract: This study evaluates the role of EPS in Prevotella intermedia for the expression of virulence. This evaluation was accomplished by comparing EPS-producing P. intermedia strains 17 and OD1-16 with non-producing P. intermedia ATCC 25611 and Porphyromonas gingivalis strains ATCC 33277, 381 and W83 for their ability to induce abscess formation in mice and evade phagocytosis.EPS-producing P. intermedia strains 17 and OD1-16 induced highly noticeable abscess lesions in mice at 107 colony-forming units (CFU). In comparison, P. intermedia ATCC 25611 and P. gingivalis ATCC 33277, 381 and W83, which all lacked the ability to produce viscous materials, required 100-fold more bacteria (109 CFU) in order to induce detectable abscess lesions in mice. Regarding antiphagocytic activity, P. intermedia strains 17 and OD1-16 were rarely internalized by human polymorphonuclear leukocytes, but other strains were readily engulfed and detected in the phagosomes of these phagocytes.These results demonstrate that the production of EPS by P. intermedia strains 17 and OD1-16 could contribute to the pathogenicity of this organism by conferring their ability to evade the host's innate defence response.Exopolysaccharide (EPS) productivities in many bacteria have been associated with pathogenicity in mammalian hosts as providing extracellular matrices to form biofilm or capsular polysaccharides attached to the cell surface [1-3]. Within biofilms, bacteria themselves are embedded in EPS and organise as a multicellular community [4]. Many gram-positive and gram-negative bacteria also produce polysaccharides that remain attached to the cell to form a capsule [5,6]. Some clinical isolates of Prevotella intermedia and Prevotella nigrescens produce mannose-rich EPSs. As revealed by electron microscopy, these clinical isolates showed dense meshwork structures around their cells [7,8], which are similar to the phenotype of other biofilm-forming bacteria such as Pseudomonas aeruginosa [9], salmonellae [10
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