Dynamic organization of chromatin domains revealed by super-resolution live-dell imaging

Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here by permission of Cell Press for personal use, not for redistribution. The definitive version was published in Molecular Cell 67 (2017): 282-293, doi:10.1016/j.molcel.2017.06.018.The eukaryotic genome is organized within cells as chromatin. For proper information output, higher-order chromatin structures can be regulated dynamically. How such structures form and behave in various cellular processes remains unclear. Here, by combining super-resolution imaging (photoactivated localization microscopy, PALM) and single nucleosome tracking, we developed a nuclear imaging system to visualize the higher-order structures along with their dynamics in live mammalian cells. We demonstrated that nucleosomes form compact domains with a peak diameter of ~160 nm and move coherently in live cells. The heterochromatin-rich regions showed more domains and less movement. With cell differentiation, the domains became more apparent, with reduced dynamics. Furthermore, various perturbation experiments indicated that they are organized by a combination of factors, including cohesin and nucleosome–nucleosome interactions. Notably, we observed the domains during mitosis, suggesting that they act as building blocks of chromosomes and may serve as information units throughout the cell cycle.This work was supported by MEXT and JSPS grants (23115005 and 16H04746, respectively) and a JST CREST grant (JPMJCR15G2).2018-07-1

Lipid flippase dysfunction as a therapeutic target for endosomal anomalies in Alzheimer's disease

Endosomal anomalies because of vesicular traffic impairment have been indicated as an early pathology of Alzheimer'vertical bar disease (AD). However, the mechanisms and therapeutic targets remain unclear. We previously reported thatbCTF, one of the pathogenic metabolites of APP, interacts with TMEM30A. TMEM30A constitutes a lipid flippase with P4-ATPase and regulates vesicular trafficking through the asymmetric distribution of phospholipids. Therefore, the alteration of lipid flippase activity in AD pathology has got attention. Herein, we showed that the interaction between beta CTF and TMEM30A suppresses the physiological formation and activity of lipid flippase in AD model cells, A7, and App(NLG-F/NLG-F) model mice. Furthermore, the T-RAP peptide derived from the beta CTF binding site of TMEM30A improved endosomal anomalies, which could be a result of the restored lipid flippase activity. Our results provide insights into the mechanisms of vesicular traffic impairment and suggest a therapeutic target for AD

Group-theoretical analysis of two-dimensional hexagonal materials

金沢大学理工研究域数物科学系Two-dimensional hexagonal materials such as graphene and silicene have highly symmetric crystal structures and Dirac cones at the K point, which induce novel electronic properties. In this report, we calculate their electronic structures by using density functional theory and analyze their band structures on the basis of the group theory. Dirac cones frequently appear when the symmetry at the K point is high; thus, two-dimensional irreducible representations are included. We discuss the relationship between symmetry and the appearance of the Dirac cone. © 2017 The Japan Society of Applied Physics.Embargo Period 12 month

Гомосексуальный субъект в пространстве публичного: нарративное измерение камин-аута

<div><p>Background</p><p>Although <i>Helicobacter pylori</i> (<i>H</i>. <i>pylori</i>) infection is closely associated with the development of peptic ulcer, its involvement in pathophysiology in the lower intestinal tract and gastrointestinal (GI) motility remains unclear. Glucagon-like peptide-1 (GLP-1) is a gut hormone produced in the lower intestinal tract and involved in GI motility. Here, we investigated the effect of <i>H</i>. <i>pylori</i> infection on the link between GLP-1 expression and motility of the GI tract.</p><p>Methods</p><p>C57BL/6 mice were inoculated with a <i>H</i>. <i>pylori</i> strain. Twelve weeks later, the <i>H</i>. <i>pylori</i>-infected mice underwent <i>H</i>. <i>pylori</i> eradication treatment. GI tissues were obtained from the mice at various time intervals, and evaluated for the severity of gastric inflammatory cell infiltration and immunohistochemical expression of GLP-1 and PAX6 in the colonic mucosa. Gastrointestinal transit time (GITT) was measured by administration of carmine-red solution.</p><p>Results</p><p>GLP-1 was expressed in the endocrine cells of the colonic mucosa, and PAX6 immunoreactivity was co-localized in such cells. The numbers of GLP-1- and PAX6-positive cells in the colon were significantly increased at 12 weeks after <i>H</i>. <i>pylori</i> infection and showed a positive correlation with each other. The GITT was significantly longer in <i>H</i>. <i>pylori</i>-infected mice than in non-infected controls and showed a positive correlation with GLP-1 expression. When <i>H</i>. <i>pylori</i>-infected mice underwent <i>H</i>. <i>pylori</i> eradication, GITT and PAX6/GLP-1 expression did not differ significantly from those in untreated <i>H</i>. <i>pylori</i>-infected mice.</p><p>Conclusions</p><p><i>H</i>. <i>pylori</i> infection may impair GI motility by enhancing the colonic GLP-1/PAX6 expression.</p></div

Dynamic Organization of Chromatin Domains Revealed by Super-Resolution Live-Cell Imaging

The eukaryotic genome is organized within cells as chromatin. For proper information output, higher-order chromatin structures can be regulated dynamically. How such structures form and behave in various cellular processes remains unclear. Here, by combining super-resolution imaging (photoactivated localization microscopy [PALM]) and single-nucleosome tracking, we developed a nuclear imaging system to visualize the higher-order structures along with their dynamics in live mammalian cells. We demonstrated that nucleosomes form compact domains with a peak diameter of ∼160 nm and move coherently in live cells. The heterochromatin-rich regions showed more domains and less movement. With cell differentiation, the domains became more apparent, with reduced dynamics. Furthermore, various perturbation experiments indicated that they are organized by a combination of factors, including cohesin and nucleosome-nucleosome interactions. Notably, we observed the domains during mitosis, suggesting that they act as building blocks of chromosomes and may serve as information units throughout the cell cycle

Rehabilitation program after mesenchymal stromal cell transplantation augmented by vascularized bone grafts for idiopathic osteonecrosis of the femoral head: a preliminary study.

[Objective]To determine the feasibility and safety of implementing a 12-week rehabilitation program after mesenchymal stromal cell (MSC) transplantation augmented by vascularized bone grafting for idiopathic osteonecrosis (ION) of the femoral head. [Design]A prospective case series. [Setting]University clinical research laboratory. [Participants]Participants (N=10) with ION who received MSC transplantation augmented by vascularized bone grafting. [Intervention]A 12-week exercise program, which included range-of-motion (ROM) exercises, muscle-strengthening exercises, and aerobic training. [Main Outcome Measures]Measures of ROM, muscle strength, Timed Up and Go test, and Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) were collected before surgery and again at 6 and 12 months after surgery. [Results]All participants completed the 12-week program. External rotation ROM as well as extensor and abductor muscle strength significantly improved 6 months after treatment compared with that before treatment (P<.05). Significant improvements were also seen in physical function, role physical, and bodily pain subgroup scores of the SF-36 (P<.05). No serious adverse events occurred. [Conclusions]This study demonstrates the feasibility and safety of a multiplex rehabilitation program after MSC transplantation and provides support for further study on the benefits of rehabilitation programs in regenerative medicine

Absence of Suction Feeding Ichthyosaurs and Its Implications for Triassic Mesopelagic Paleoecology

Mesozoic marine reptiles and modern marine mammals are often considered ecological analogs, but the extent of their similarity is largely unknown. Particularly important is the presence/absence of deep-diving suction feeders among Mesozoic marine reptiles because this would indicate the establishment of mesopelagic cephalopod and fish communities in the Mesozoic. A recent study suggested that diverse suction feeders, resembling the extant beaked whales, evolved among ichthyosaurs in the Triassic. However, this hypothesis has not been tested quantitatively. We examined four osteological features of jawed vertebrates that are closely linked to the mechanism of suction feeding, namely hyoid corpus ossification/calcification, hyobranchial apparatus robustness, mandibular bluntness, and mandibular pressure concentration index. Measurements were taken from 18 species of Triassic and Early Jurassic ichthyosaurs, including the presumed suction feeders. Statistical comparisons with extant sharks and marine mammals of known diets suggest that ichthyosaurian hyobranchial bones are significantly more slender than in suction-feeding sharks or cetaceans but similar to those of ram-feeding sharks. Most importantly, an ossified hyoid corpus to which hyoid retractor muscles attach is unknown in all but one ichthyosaur, whereas a strong integration of the ossified corpus and cornua of the hyobranchial apparatus has been identified in the literature as an important feature of suction feeders. Also, ichthyosaurian mandibles do not narrow rapidly to allow high suction pressure concentration within the oral cavity, unlike in beaked whales or sperm whales. In conclusion, it is most likely that Triassic and Early Jurassic ichthyosaurs were 'ram-feeders', without any beaked-whale-like suction feeder among them. When combined with the inferred inability for dim-light vision in relevant Triassic ichthyosaurs, the fossil record of ichthyosaurs does not suggest the establishment of modern-style mesopelagic animal communities in the Triassic. This new interpretation matches the fossil record of coleoids, which indicates the absence of soft-bodied deepwater species in the Triassic