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  • 1
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    An early phase of environmental effects on galaxy properties unveiled by near-infrared spectroscopy of protocluster galaxies at z 〉 2 (2015)
    Oxford University Press
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    Publication Date: 2015-02-08
    Description: This work presents the results from our near-infrared spectroscopy of narrow-band-selected Hα emitters (HAEs) in two rich overdensities (PKS 1138–262 at z  = 2.2 and USS 1558–003 at z  = 2.5) with the Multi-Object Infrared Camera and Spectrograph on the Subaru telescope. These protoclusters are promising candidates for the most massive class of galaxy clusters seen today (Paper I). The confirmed HAEs in the protoclusters at z  〉 2 show high excitation levels as characterized by much higher [O iii ]/Hβ or [O iii ]/Hα line ratios than those of general galaxies at low- z . Such a high excitation level may not only be driven by high specific star formation rates and lower gaseous metallicities, but also be contributed by some other effects. We investigate the environmental dependence of gaseous metallicities by comparing the HAEs in the protoclustrers with those in the general field at similar redshifts. We find that the gaseous metallicities of protocluster galaxies are more chemically enriched than those of field galaxies at a given stellar mass in the range of M *   10 11 M . This can be attributed to many processes, such as intrinsic (or nature) effects, external (or nurture) effects, and/or some systematic sampling effects. The intrinsic (nature) effect leads to the advanced stage of ‘downsizing’ galaxy evolution in protoclusters. On the other hand, the external (nurture) effects include the recycling of chemically enriched gas due to the higher pressure of intergalactic medium and/or stripping of outer gas in the reservoir in protoclusters. We also find that the offset of the mass–metallicity relation in dense environment becomes larger at higher redshifts. This can be naturally understood by the fact that the inflow/outflow rates in star-forming galaxies are much higher at higher redshifts. Therefore, the environmental dependence of such ‘feeding’ and ‘feedback’ mechanisms in galaxy formation is probably playing major roles in producing the offset of the mass–metallicity relation for the protocluster galaxies at z  〉 2.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
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  • 2
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    The Human GATA1 Gene Retains a 5' Insulator That Maintains Chromosomal Architecture and GATA1 Expression Levels in Splenic Erythroblasts [Articles] (2015)
    The American Society for Microbiology (ASM)
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    Publication Date: 2015-04-22
    Description: GATA1 is a key transcription factor for erythropoiesis. GATA1 gene expression is strictly regulated at the transcriptional level. While the regulatory mechanisms governing mouse Gata1 ( mGata1 ) gene expression have been studied extensively, how expression of the human GATA1 ( hGATA1 ) gene is regulated remains to be elucidated. To address this issue, we generated hGATA1 bacterial artificial chromosome (BAC) transgenic mouse lines harboring a 183-kb hGATA1 locus covering the hGATA1 exons and distal flanking sequences. Transgenic hGATA1 expression coincides with endogenous mGata1 expression and fully rescues hematopoietic deficiency in mGata1 knockdown mice. The transgene exhibited copy number-dependent and integration position-independent expression of hGATA1 , indicating the presence of chromatin insulator activity within the transgene. We found a novel insulator element at 29 kb 5' to the hGATA1 gene and refer to this element as the 5' CCCTC-binding factor (CTCF) site. Substitution mutation of the 5' CTCF site in the hGATA1 BAC disrupted the chromatin architecture and led to a reduction of hGATA1 expression in splenic erythroblasts under conditions of stress erythropoiesis. Our results demonstrate that expression of the hGATA1 gene is regulated through the chromatin architecture organized by 5' CTCF site-mediated intrachromosomal interactions in the hGATA1 locus.
    Print ISSN: 0270-7306
    Electronic ISSN: 1098-5549
    Topics: Biology , Medicine
    Published by The American Society for Microbiology (ASM)
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  • 3
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    The Levels of Brachyspira hyodysenteriae Binding to Porcine Colonic Mucins Differ between Individuals, and Binding Is Increased to Mucins from Infected Pigs with De Novo MUC5AC Synthesis [Bacterial Infections] (2015)
    The American Society for Microbiology (ASM)
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    Publication Date: 2015-03-18
    Description: Brachyspira hyodysenteriae colonizes the pig colon, resulting in mucohemorrhagic diarrhea and growth retardation. Fecal mucus is a characteristic feature of swine dysentery; therefore, we investigated how the mucin environment changes in the colon during infection with B. hyodysenteriae and how these changes affect this bacterium's interaction with mucins. We isolated and characterized mucins, the main component of mucus, from the colon of experimentally inoculated and control pigs and investigated B. hyodysenteriae binding to these mucins. Fluorescence microscopy revealed a massive mucus induction and disorganized mucus structure in the colon of pigs with swine dysentery. Quantitative PCR (qPCR) and antibody detection demonstrated that the mucus composition of pigs with swine dysentery was characterized by de novo expression of MUC5AC and increased expression of MUC2 in the colon. Mucins from the colon of inoculated and control pigs were isolated by two steps of isopycnic density gradient centrifugation. The mucin densities of control and inoculated pigs were similar, whereas the mucin quantity was 5-fold higher during infection. The level of B. hyodysenteriae binding to mucins differed between pigs, and there was increased binding to soluble mucins isolated from pigs with swine dysentery. The ability of B. hyodysenteriae to bind, measured in relation to the total mucin contents of mucus in sick versus healthy pigs, increased 7-fold during infection. Together, the results indicate that B. hyodysenteriae binds to carbohydrate structures on the mucins as these differ between individuals. Furthermore, B. hyodysenteriae infection induces changes to the mucus niche which substantially increase the amount of B. hyodysenteriae binding sites in the mucus.
    Print ISSN: 0019-9567
    Electronic ISSN: 1098-5522
    Topics: Medicine
    Published by The American Society for Microbiology (ASM)
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  • 4
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    Association of hair dye use with circulating levels of sex hormones in premenopausal Japanese women (2015)
    Oxford University Press
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    Publication Date: 2015-09-26
    Description: Background: Substances identified as animal carcinogens are no longer used as ingredients of hair dyes. However, hair dyes are diverse groups of chemicals, and certain compounds may affect endogenous sex hormone levels. We examined the association between hair dye use and sex hormone levels among premenopausal women. Methods: Study subjects were 431 premenopausal Japanese women who had regular menstrual cycles less than 40 days long. Information on the use of hair dyes or hair bleach, the type of hair coloring used, the duration of use and the frequency of application was collected using a self-administered questionnaire. Fasting plasma samples were obtained to measure estradiol, testosterone, dehydroepiandrosterone sulfate, sex hormone-binding globulin, follicle-stimulating hormone and luteinizing hormone. Results: After controlling for covariates, the mean plasma total testosterone level was about 14% higher in women who had used hair dyes for 10 or more years than that among women who had never used them ( P for trend = 0.02). A similar association was observed when the type of hair dye was restricted to permanent hair dyes. A higher frequency of applying non-permanent hair dyes was marginally significantly associated with higher total and free estradiol levels. Conclusions: Data suggest that long-term use of hair dyes may be associated with an increase in circulating testosterone levels. As this is, to our knowledge, the first study examining the association between hair dye use and sex hormone levels, replication of the results is required.
    Print ISSN: 1101-1262
    Electronic ISSN: 1464-360X
    Topics: Medicine
    Published by Oxford University Press
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  • 5
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    Whole-Body In Vivo Monitoring of Inflammatory Diseases Exploiting Human Interleukin 6-Luciferase Transgenic Mice [Articles] (2015)
    The American Society for Microbiology (ASM)
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    Publication Date: 2015-09-18
    Description: Chronic inflammation underlies the pathological progression of various diseases, and thus many efforts have been made to quantitatively evaluate the inflammatory status of the diseases. In this study, we generated a highly sensitive inflammation-monitoring mouse system using a bacterial artificial chromosome (BAC) clone containing extended flanking sequences of the human interleukin 6 gene ( hIL6 ) locus, in which the luciferase (Luc) reporter gene is integrated ( hIL6 -BAC- Luc ). We successfully monitored lipopolysaccharide-induced systemic inflammation in various tissues of the hIL6 -BAC- Luc mice using an in vivo bioluminescence imaging system. When two chronic inflammatory disease models, i.e., a genetic model of atopic dermatitis and a model of experimental autoimmune encephalomyelitis (EAE), were applied to the hIL6 -BAC- Luc mice, luciferase bioluminescence was specifically detected in the atopic skin lesion and central nervous system, respectively. Moreover, the Luc activities correlated well with the disease severity. Nrf2 is a master transcription factor that regulates antioxidative and detoxification enzyme genes. Upon EAE induction, the Nrf2-deficient mice crossed with the hIL6 -BAC- Luc mice exhibited enhanced neurological symptoms concomitantly with robust luciferase luminescence in the neuronal tissue. Thus, whole-body in vivo monitoring using the hIL6 -BAC- Luc transgenic system (WIM-6 system) provides a new and powerful diagnostic tool for real-time in vivo monitoring of inflammatory status in multiple different disease models.
    Print ISSN: 0270-7306
    Electronic ISSN: 1098-5549
    Topics: Biology , Medicine
    Published by The American Society for Microbiology (ASM)
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  • 6
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    Amelioration of sickle cell pathology by Nrf2 [Medical Sciences] (2015)
    National Academy of Sciences
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    Publication Date: 2015-09-30
    Description: Sickle cell disease (SCD) is an inherited disorder caused by a point mutation in the β-globin gene, leading to the production of abnormally shaped red blood cells. Sickle cells are prone to hemolysis and thereby release free heme into plasma, causing oxidative stress and inflammation that in turn result in...
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
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  • 7
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    Splicing inhibition decreases phosphorylation level of Ser2 in Pol II CTD (2015)
    Oxford University Press
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    Publication Date: 2015-09-30
    Description: Phosphorylation of the C-terminal domain of the largest subunit of RNA polymerase II (Pol II), especially Ser2 and Ser5 residues, plays important roles in transcription and mRNA processing, including 5' end capping, splicing and 3' end processing. These phosphorylation events stimulate mRNA processing, however, it is not clear whether splicing activity affects the phosphorylation status of Pol II. In this study, we found that splicing inhibition by potent splicing inhibitors spliceostatin A (SSA) and pladienolide B or by antisense oligos against snRNAs decreased phospho-Ser2 level, but had little or no effects on phospho-Ser5 level. In contrast, transcription and translation inhibitors did not decrease phospho-Ser2 level, therefore inhibition of not all the gene expression processes cause the decrease of phospho-Ser2. SSA treatment caused early dissociation of Pol II and decrease in phospho-Ser2 level of chromatin-bound Pol II, suggesting that splicing inhibition causes downregulation of phospho-Ser2 through at least these two mechanisms.
    Print ISSN: 0305-1048
    Electronic ISSN: 1362-4962
    Topics: Biology
    Published by Oxford University Press
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  • 8
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    Predicting dust extinction properties of star-forming galaxies from H{alpha}/UV ratio (2015)
    Oxford University Press
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    Publication Date: 2015-08-24
    Description: Using star-forming galaxies sample in the nearby Universe (0.02 〈  z  〈 0.10) selected from the Sloan Digital Sky Survey (DR7) and Galaxy Evolution Explorer all-sky survey (GR5), we present a new empirical calibration for predicting dust extinction of galaxies from the Hα-to-FUV flux ratio. We find that the Hα dust extinction ( A Hα ) derived with Hα/Hβ ratio (Balmer decrement) increases with increasing Hα/UV ratio as expected, but there remains a considerable scatter around the relation, which is largely dependent on stellar mass and/or Hα equivalent width (EW Hα ). At fixed Hα/UV ratio, galaxies with higher stellar mass (or galaxies with lower EW Hα ) tend to be more highly obscured by dust. We quantify this trend and establish an empirical calibration for predicting A Hα with a combination of Hα/UV ratio, stellar mass, and EW Hα , with which we can successfully reduce the systematic uncertainties accompanying the simple Hα/UV approach by ~15–30 per cent. The new recipes proposed in this study will provide a convenient tool for predicting dust extinction level of galaxies particularly when Balmer decrement is not available. By comparing A Hα (derived with Balmer decrement) and A UV (derived with IR/UV luminosity ratio) for a subsample of galaxies for which AKARI far-infrared photometry is available, we demonstrate that more massive galaxies tend to have higher extra extinction towards the nebular regions compared to the stellar continuum light. Considering recent studies reporting smaller extra extinction towards nebular regions for high-redshift galaxies, we argue that the dust geometry within high-redshift galaxies resembles low-mass galaxies in the nearby Universe.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
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  • 9
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    Regulation of the Oil Body-Peroxisome Interaction [Plant Biology] (2016)
    The American Society for Biochemistry and Molecular Biology (ASBMB)
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    Publication Date: 2016-09-17
    Description: Physical interaction between organelles is a flexible event and essential for cells to adapt rapidly to environmental stimuli. Germinating plants utilize oil bodies and peroxisomes to mobilize storage lipids for the generation of sucrose as the main energy source. Although membrane interaction between oil bodies and peroxisomes has been widely observed, its underlying molecular mechanism is largely unknown. Here we present genetic evidence for control of the physical interaction between oil bodies and peroxisomes. We identified alleles of the sdp1 mutant altered in oil body morphology. This mutant accumulates bigger and more oil body aggregates compared with the wild type and showed defects in lipid mobilization during germination. SUGAR DEPENDENT 1 (SDP1) encodes major triacylglycerol lipase in Arabidopsis. Interestingly, sdp1 seedlings show enhanced physical interaction between oil bodies and peroxisomes compared with the wild type, whereas exogenous sucrose supplementation greatly suppresses the interaction. The same phenomenon occurs in the peroxisomal defective 1 (ped1) mutant, defective in lipid mobilization because of impaired peroxisomal β-oxidation, indicating that sucrose production is a key factor for oil body-peroxisomal dissociation. Peroxisomal dissociation and subsequent release from oil bodies is dependent on actin filaments. We also show that a peroxisomal ATP binding cassette transporter, PED3, is the potential anchor protein to the membranes of these organelles. Our results provide novel components linking lipid metabolism and oil body-peroxisome interaction whereby sucrose may act as a negative signal for the interaction of oil bodies and peroxisomes to fine-tune lipolysis.
    Print ISSN: 0021-9258
    Electronic ISSN: 1083-351X
    Topics: Biology , Chemistry and Pharmacology
    Published by The American Society for Biochemistry and Molecular Biology (ASBMB)
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  • 10
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    The chimeric GLK repressors induce closed stomata [Plant Biology] (2016)
    National Academy of Sciences
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    Publication Date: 2016-04-13
    Description: Stomatal movements regulate gas exchange, thus directly affecting the efficiency of photosynthesis and the sensitivity of plants to air pollutants such as ozone. The GARP family transcription factors GOLDEN 2-LIKE1 (GLK1) and GLK2 have known functions in chloroplast development. Here, we show that Arabidopsis thaliana (A. thaliana) plants expressing the...
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
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