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1 0 0 0 OA Distribution of the Sex-Determining Gene MID and Molecular Correspondence of Mating Types within the Isogamous Genus Gonium (Volvocales, Chlorophyta).

著者: Hamaji Takashi Ferris Patrick J Nishii Ichiro Nishimura Yoshiki Nozaki Hisayoshi
出版者: Public Library of Science
雑誌: PloS one (ISSN:19326203)
巻号頁・発行日: vol.8, no.5, 2013-05
被引用文献数: 16

[Background]Isogamous organisms lack obvious cytological differences in the gametes of the two complementary mating types. Consequently, it is difficult to ascertain which of the two mating types are homologous when comparing related but sexual isolated strains or species. The colonial volvocalean algal genus Gonium consists of such isogamous organisms with heterothallic mating types designated arbitrarily as plus or minus in addition to homothallic strains. Homologous molecular markers among lineages may provide an “objective” framework to assign heterothallic mating types. [Methodology/Principal Findings]Using degenerate primers designed based on previously reported MID orthologs, the “master regulator” of mating types/sexes in the colonial Volvocales, MID homologs were identified and their presence/absence was examined in nine strains of four species of Gonium. Only one of the two complementary mating types in each of the four heterothallic species has a MIDhomolog. In addition to heterothallic strains, a homothallic strain of G. multicoccum has MID. Molecular evolutionary analysis suggests that MID of this homothallic strain retains functional constraint comparable to that of the heterothallic strains. [Conclusion/Significance]We coordinated mating genotypes based on presence or absence of a MID homolog, respectively, in heterothallic species. This scheme should be applicable to heterothallic species of other isogamous colonial Volvocales including Pandorina and Yamagishiella. Homothallism emerged polyphyletically in the colonial Volvocales, although its mechanism remains unknown. Our identification of a MID homolog for a homothallic strain of G.multicoccum suggests a MID-dependent mechanism is involved in the sexual developmental program of this homothallic species.

2013-06-05 11:32:37
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1 0 0 0 OA Descriptive Analysis of Patients’ EMS Use Related to Severity in Tokyo: A Population-Based Observational Study

著者: Abe Toshikazu Ishimatsu Shinichi Tokuda Yasuharu
出版者: Public Library of Science
雑誌: PLoS ONE (ISSN:19326203)
巻号頁・発行日: vol.8, no.3, pp.e59738, 2013-03
被引用文献数: 3

IntroductionFew studies are available on the clinical characteristics of patients using emergency medical transports in Japan. In this study, we aimed to investigate reasons for emergency medical transports and their relation to clinical severity.MethodsWe conducted a 3-year population-based observational study of patients transported by ambulance to emergency departments (ED) in the capital of Japan, Tokyo, which has a population of about 13 million. Demographic data, reasons for transport, and the severity of initial assessment at ED were recorded. Logistic regression was used to determine the odds of the clinical severity of each reason for transport.ResultsThe number of emergency medical transports in the three-year study period was 1,832,637. Mean age was 53±26. Males were 976,142 (53%). Overall, 92% of all transported patients were in a mild or moderate medical state and patients with the 17 most frequent reasons for transport occupied 82% (1,506,017) of all transports. Pain was the most frequent reason for transport, followed by traffic accident. Considering all the patients and their reasons for transport, patients whose reason was pain or a traffic accident (29% of all patients) were in a relatively mild state compared with patients with other reasons for transport. Patients in an altered mental state in the prehospital setting (6.8% of all patients) were in a more severe medical state than other patients.ConclusionsIn Tokyo, Japan, 92% of transported patients were in a mild or moderate medical state. In particular, most patients from traffic accidents were in a mild state, even though traffic accidents were the second most frequent reason for transport. Patients in an altered mental state were most likely to be in a severe medical state.

2013-06-05 08:31:56
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1 0 0 0 OA Anisotropic Alteration of Scleral Birefringence to Uniaxial Mechanical Strain

著者: Nagase Satoko Yamanari Masahiro Tanaka Ryosuke Yasui Takeshi Miura Masahiro Iwasaki Takuya Goto Hiroshi Yasuno Yoshiaki
出版者: Public Library of Science
雑誌: PLoS ONE (ISSN:19326203)
巻号頁・発行日: vol.8, no.3, pp.e58716, 2013-03
被引用文献数: 13 5

PurposeTo investigate the relationship between scleral mechanical properties, its birefringence, and the anisotropy of birefringence alteration in respect of the direction of the strain by using PS-OCT.MethodsThe scleral birefringence of thirty-nine porcine eyes was measured with a prototype PS-OCT. A rectangle strip of sclera with a width of 4 mm was dissected at the temporal region 5 mm apart from the optic nerve head. The strain and force were measured with a uniaxial tension tester as the sample was stretched with a speed of 1.8 mm/min after preconditioning. The birefringence of the sample was measured by PS-OCT at the center of the sample before applying, denoted as inherent birefringence, and after applying stretching of 6.5% strain. The birefringence alteration was obtained by these two measurements and correlations between birefringence and elastic parameters, tangent modulus, and structural stiffness were examined. Twenty and 19 porcine eyes were stretched in meridional or equatorial directions, respectively.ResultsA moderate positive correlation was found between the inherent birefringence and the structural stiffness. A moderate positive correlation was also found between the inherent birefringence and the tangent modulus. The birefringence increased by strains. Marginal significance was found in the birefringence alteration between meridional and equatorial strains, where the mean birefringence elevation by meridional strain was higher than that by equatorial strain.ConclusionsThe birefringence was found to be altered by applying strain and also be related with inherent birefringence. This implies the birefringence of the sclera of the in vivo eye also could be affected by its mechanical property.Citation: Nagase S, Yamanari M, Tanaka R, Yasui T, Miura M, et al. (2013) Anisotropic Alteration of Scleral Birefringence to Uniaxial Mechanical Strain. PLoS ONE 8(3): e58716. doi:10.1371/journal.pone.0058716Editor: Laurent Kreplak, Dalhousie University, CanadaReceived: October 30, 2012; Accepted: February 5, 2013; Published: March 11, 2013Copyright: © 2013 Nagase et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Funding: Financial support for this study was provided in part by Japan Science Technology Agency. YY had financial interest in Tomey Corp. MY is an employee of Tomey Corp. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Competing interests: The authors have read the journal's policy and have the following conflicts: Yasuno and Yamanari are supported by a research grant from Tomey Corp. through their institution. Yamanari is now employee of Tomey Corporation. This does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials.

2013-05-17 08:32:00
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1 0 0 0 OA Mitochondrial DNA Mutations in Mutator Mice Confer Respiration Defects and B-Cell Lymphoma Development

著者: Mito Takayuki Kikkawa Yoshiaki Shimizu Akinori Hashizume Osamu Katada Shun Imanishi Hirotake Ota Azusa Kato Yukina Nakada Kazuto Hayashi Jun-Ichi
出版者: Public Library of Science
雑誌: PLoS ONE (ISSN:19326203)
巻号頁・発行日: vol.8, no.2, pp.e55789, 2013-02
被引用文献数: 26 5

Mitochondrial DNA (mtDNA) mutator mice are proposed to express premature aging phenotypes including kyphosis and hair loss (alopecia) due to their carrying a nuclear-encoded mtDNA polymerase with a defective proofreading function, which causes accelerated accumulation of random mutations in mtDNA, resulting in expression of respiration defects. On the contrary, transmitochondrial mito-miceΔ carrying mtDNA with a large-scale deletion mutation (ΔmtDNA) also express respiration defects, but not express premature aging phenotypes. Here, we resolved this discrepancy by generating mtDNA mutator mice sharing the same C57BL/6J (B6J) nuclear background with that of mito-miceΔ. Expression patterns of premature aging phenotypes are very close, when we compared between homozygous mtDNA mutator mice carrying a B6J nuclear background and selected mito-miceΔ only carrying predominant amounts of ΔmtDNA, in their expression of significant respiration defects, kyphosis, and a short lifespan, but not the alopecia. Therefore, the apparent discrepancy in the presence and absence of premature aging phenotypes in mtDNA mutator mice and mito-miceΔ, respectively, is partly the result of differences in the nuclear background of mtDNA mutator mice and of the broad range of ΔmtDNA proportions of mito-miceΔ used in previous studies. We also provided direct evidence that mtDNA abnormalities in homozygous mtDNA mutator mice are responsible for respiration defects by demonstrating the co-transfer of mtDNA and respiration defects from mtDNA mutator mice into mtDNA-less (ρ0) mouse cells. Moreover, heterozygous mtDNA mutator mice had a normal lifespan, but frequently developed B-cell lymphoma, suggesting that the mtDNA abnormalities in heterozygous mutator mice are not sufficient to induce a short lifespan and aging phenotypes, but are able to contribute to the B-cell lymphoma development during their prolonged lifespan.

2013-05-14 08:30:57
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1 0 0 0 OA A Reduction in Age-Enhanced Gluconeogenesis Extends Lifespan

著者: Hachinohe Mayumi Yamane Midori Akazawa Daiki Ohsawa Kazuhiro Ohno Mayumi Terashita Yuzu Masumoto Hiroshi
出版者: Public Library of Science
雑誌: PLoS ONE (ISSN:19326203)
巻号頁・発行日: vol.8, no.1, pp.e54011, 2013-01
被引用文献数: 14

The regulation of energy metabolism, such as calorie restriction (CR), is a major determinant of cellular longevity. Although augmented gluconeogenesis is known to occur in aged yeast cells, the role of enhanced gluconeogenesis in aged cells remains undefined. Here, we show that age-enhanced gluconeogenesis is suppressed by the deletion of the tdh2 gene, which encodes glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a protein that is involved in both glycolysis and gluconeogenesis in yeast cells. The deletion of TDH2 restores the chronological lifespan of cells with deletions of both the HST3 and HST4 genes, which encode yeast sirtuins, and represses the activation of gluconeogenesis. Furthermore, the tdh2 gene deletion can extend the replicative lifespan in a CR pathway-dependent manner. These findings demonstrate that the repression of enhanced gluconeogenesis effectively extends the cellular lifespan.

2013-03-15 08:31:18
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1 0 0 0 OA Optical Rheology of Porcine Sclera by Birefringence Imaging

著者: Yamanari Masahiro Ishii Kotaro Fukuda Shinichi Lim Yiheng Duan Lian Makita Shuichi Miura Masahiro Oshika Tetsuro Yasuno Yoshiaki
出版者: Public Library of Science
雑誌: PLoS ONE (ISSN:19326203)
巻号頁・発行日: vol.7, no.9, pp.e44026, 2012-09
被引用文献数: 26 5

PurposeTo investigate a relationship between birefringence and elasticity of porcine sclera ex vivo using polarization-sensitive optical coherence tomography (PS-OCT).MethodsElastic parameters and birefringence of 19 porcine eyes were measured. Four pieces of scleral strips which were parallel to the limbus, with a width of 4 mm, were dissected from the optic nerve head to the temporal side of each porcine eye. Birefringence of the sclera was measured with a prototype PS-OCT. The strain and force were measured with a uniaxial material tester as the sample was stretched with a speed of 1.8 mm/min after preconditioning. A derivative of the exponentially-fitted stress-strain curve at 0% strain was extracted as the tangent modulus. Power of exponential stress-strain function was also extracted from the fitting. To consider a net stiffness of sclera, structural stiffness was calculated as a product of tangent modulus and thickness. Correlations between birefringence and these elastic parameters were examined.ResultsStatistically significant correlations between birefringence and all of the elastic parameters were found at 2 central positions. Structural stiffness and power of exponential stress-strain function were correlated with birefringence at the position near the optic nerve head. No correlation was found at the position near the equator.ConclusionsThe evidence of correlations between birefringence and elasticity of sclera tested uniaxially was shown for the first time. This work may become a basis for in vivo measurement of scleral biomechanics using PS-OCT.