89 research outputs found
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
Cooking Vessels, Volumes, and Venues: Evidence from LM IIIC Kavousi Vronda and Karphi
Glowacki, K.T., and L.P. Day. “Cooking Vessels, Volumes, and Venues: Evidence from LM IIIC Kavousi Vronda and Karphi.” Abstract of paper read at Διατροφικές συνήθειες και πρακτικές στην Κρήτη διαχρονικά [Dietary Habits and Practices in Crete over Time], Museum of Cretan Ethnology, Voroi, Crete, Greece, September 9–10, 2017.Our understanding of diet and culinary practices at the Late Minoan IIIC settlement sites of Kavousi Vronda and Karphi is based upon several different types of physical evidence that have been recovered through excavation. These include the botanical and faunal remains of plants and animals available to and consumed by the inhabitants; ceramic vessels used for the cooking and consumption of food and drink; built and fixed cooking installations, such as hearths and ovens; and the architectural spaces within the settlements where food preparation and consumption most likely took place. Each type of evidence is, by itself, incomplete and dependent upon differential preservation resulting from site formation processes specific to each archaeological context. Taken together, however, they allow us to gain important insights into key aspects of food cultivation, provisioning, processing, preparation, and convivial practices on Crete in the 12th and 11th centuries BC. In this paper, we will compare and contrast the evidence for food preparation and dining at each site, paying special attention to the forms and sizes of ceramic vessels used for cooking and consumption
集中開講による物作り授業の実践
We performed a intensive course in an elective subject by the workshop seminar of theproduction for the first time during summer vacation. We open a course in 3 themes every year so farfor four years and each theme piles up improvement every year. We let a student choose 1 themeamong a velocity of the wind vehicle, the large size paper glider and the stirling engine now. Thosethemes have personal production or group production, and there is a thing to design originally orproduction it according to a drawing again, and there is variety. Our students to choose surpass 60%of a class. They learn behaviorally and achieve enough result
Clustering of Lyman Break Galaxies at z=4 and 5 in The Subaru Deep Field: Luminosity Dependence of The Correlation Function Slope
We explored the clustering properties of Lyman Break Galaxies (LBGs) at z=4
and 5 with an angular two-point correlation function on the basis of the very
deep and wide Subaru Deep Field data. We found an apparent dependence of the
correlation function slope on UV luminosity for LBGs at both z=4 and 5. More
luminous LBGs have a steeper correlation function. To compare these
observational results, we constructed numerical mock LBG catalogs based on a
semianalytic model of hierarchical clustering combined with high-resolution
N-body simulation, carefully mimicking the observational selection effects. The
luminosity functions for LBGs predicted by this mock catalog were found to be
almost consistent with the observation. Moreover, the overall correlation
functions of LBGs were reproduced reasonably well. The observed dependence of
the clustering on UV luminosity was not reproduced by the model, unless
subsamples of distinct halo mass were considered. That is, LBGs belonging to
more massive dark haloes had steeper and larger-amplitude correlation
functions. With this model, we found that LBG multiplicity in massive dark
halos amplifies the clustering strength at small scales, which steepens the
slope of the correlation function. The hierarchical clustering model could
therefore be reconciled with the observed luminosity-dependence of the angular
correlation function, if there is a tight correlation between UV luminosity and
halo mass. Our finding that the slope of the correlation function depends on
luminosity could be an indication that massive dark halos hosted multiple
bright LBGs (abridged).Comment: 16 pages, 17 figures, Accepted for publication in ApJ, Full
resolution version is available at
http://zone.mtk.nao.ac.jp/~kashik/sdf/acf/sdf_lbgacf.pd
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
Simulation of developmental changes in action potentials with ventricular cell models
During cardiomyocyte development, early embryonic ventricular cells show spontaneous activity that disappears at a later stage. Dramatic changes in action potential are mediated by developmental changes in individual ionic currents. Hence, reconstruction of the individual ionic currents into an integrated mathematical model would lead to a better understanding of cardiomyocyte development. To simulate the action potential of the rodent ventricular cell at three representative developmental stages, quantitative changes in the ionic currents, pumps, exchangers, and sarcoplasmic reticulum (SR) Ca2+ kinetics were represented as relative activities, which were multiplied by conductance or conversion factors for individual ionic systems. The simulated action potential of the early embryonic ventricular cell model exhibited spontaneous activity, which ceased in the simulated action potential of the late embryonic and neonatal ventricular cell models. The simulations with our models were able to reproduce action potentials that were consistent with the reported characteristics of the cells in vitro. The action potential of rodent ventricular cells at different developmental stages can be reproduced with common sets of mathematical equations by multiplying conductance or conversion factors for ionic currents, pumps, exchangers, and SR Ca2+ kinetics by relative activities
Down-Sizing in Galaxy Formation at z~1 in the Subaru/XMM-Newton Deep Survey (SXDS)
We use the deep wide-field optical imaging data of the Subaru/XMM-Newton Deep
Survey (SXDS) to discuss the luminosity (mass) dependent galaxy colours down to
z'=25.0 (5 x 10^9 h_{70}^{-2} Msun) for z~1 galaxies in colour-selected high
density regions. We find an apparent absence of galaxies on the red
colour-magnitude sequence below z'~24.2, corresponding to ~M*+2 (~10^{10} Msun)
with respect to passively evolving galaxies at z~1. Galaxies brighter than
M*-0.5 (8 x 10^{10} Msun), however, are predominantly red passively evolving
systems, with few blue star forming galaxies at these magnitudes.
This apparent age gradient, where massive galaxies are dominated by old
stellar populations while less massive galaxies have more extended star
formation histories, supports the `down-sizing' idea where the mass of galaxies
hosting star formation decreases as the Universe ages. Combined with the lack
of evolution in the shape of the stellar mass function for massive galaxies
since at least z~1, it appears that galaxy formation processes (both star
formation and mass assembly) should have occurred in an accelerated way in
massive systems in high density regions, while these processes should have been
slower in smaller systems. This result provides an interesting challenge for
modern CDM-based galaxy formation theories which predict later formation epochs
of massive systems, commonly referred to as ``bottom-up''.Comment: proof corrected version (MNRAS in press), 10 pages, 12 figures (of
which 3 are in jpg format
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