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Luo J, Lu Z, Zhong Z, Pi M, Xiong Y, Li L, Chen T, Chen Y, Wang CY, Liu Z, Ye Q. ALDH2 deficiency exacerbates MCD-diet induced MASLD by modulating bile acid metabolism. Free Radic Biol Med 2024; 212:34-48. [PMID: 38104741 DOI: 10.1016/j.freeradbiomed.2023.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 12/10/2023] [Accepted: 12/14/2023] [Indexed: 12/19/2023]
Abstract
Aldehyde dehydrogenase 2 (ALDH2), an acetaldehyde dehydrogenase in mitochondria, is primarily responsible for metabolizing alcohol-derived acetaldehyde and other endogenous aldehydes. Inactivating ALDH2 rs671 polymorphism is found in up to 8 % of the global population and 40 % of the East Asian population. Recent studies have shown that rs671 SNP mutation in the human ALDH2 gene is associated with an increased risk of metabolic dysfunction-associated steatotic liver diseases (MASLD), but the mechanism remains unclear. Here, we identify the role of ALDH2 in MASLD. Firstly, ALDH2 activity was lower in MASLD patients and the methionine-choline deficiency (MCD) diet induced MASLD model. Secondly, activation of ALDH2 activity with Alda-1 (ALDH2 agonist) attenuated MCD-diet induced hepatic triglyceride (TG) accumulation and steatosis, whereas the opposite result was observed with cyanamide (CYA, ALDH2 inhibitor). Furthermore, ALDH2 deficiency exacerbated hepatic steatosis, inflammation, and fibrosis in the MCD-diet induced mice. RNA sequencing (RNA-seq) revealed that oxysterol 7-α hydroxylase (Cyp7b1) and the related metabolic pathway significantly changed in the MCD-diet challenged ALDH2-/- mice. In ALDH2-/- mice, the expression of Cyp7b1 was downregulated and FXR/SHP signaling was inhibited, reducing the alternative bile acid (BA) synthetic pathway. In our in vitro experiments, knockdown of ALDH2 exacerbated TG accumulation in hepatocytes, whereas the opposite result was observed with overexpression of ALDH2. Moreover, chenodeoxycholic acid (CDCA) rescued ALDH2 downregulation induced TG accumulation in hepatocytes. Our study reveals that ALDH2 attenuates hepatocyte steatosis by regulating the alternative BA synthesis pathway, and ALDH2 may serve as a potential target for the treatment of MASLD.
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Affiliation(s)
- Jun Luo
- National Quality Control Center for Donated Organ Procurement, Hubei Key Laboratory of Medical Technology on Transplantation, Hubei Clinical Research Center for Natural Polymer Biological Liver, Hubei Engineering Center of Natural Polymer-Based Medical Materials, Zhongnan Hospital of Wuhan University, Institute of Hepatobiliary Diseases of Wuhan University, Transplant Center of Wuhan University, Wuhan, Hubei, China
| | - Zhongshan Lu
- National Quality Control Center for Donated Organ Procurement, Hubei Key Laboratory of Medical Technology on Transplantation, Hubei Clinical Research Center for Natural Polymer Biological Liver, Hubei Engineering Center of Natural Polymer-Based Medical Materials, Zhongnan Hospital of Wuhan University, Institute of Hepatobiliary Diseases of Wuhan University, Transplant Center of Wuhan University, Wuhan, Hubei, China
| | - Zibiao Zhong
- National Quality Control Center for Donated Organ Procurement, Hubei Key Laboratory of Medical Technology on Transplantation, Hubei Clinical Research Center for Natural Polymer Biological Liver, Hubei Engineering Center of Natural Polymer-Based Medical Materials, Zhongnan Hospital of Wuhan University, Institute of Hepatobiliary Diseases of Wuhan University, Transplant Center of Wuhan University, Wuhan, Hubei, China
| | - Meichen Pi
- Shenzhen Qianhai Taikang Hospital, Shenzhen, Guangdong, China
| | - Yan Xiong
- National Quality Control Center for Donated Organ Procurement, Hubei Key Laboratory of Medical Technology on Transplantation, Hubei Clinical Research Center for Natural Polymer Biological Liver, Hubei Engineering Center of Natural Polymer-Based Medical Materials, Zhongnan Hospital of Wuhan University, Institute of Hepatobiliary Diseases of Wuhan University, Transplant Center of Wuhan University, Wuhan, Hubei, China
| | - Ling Li
- National Quality Control Center for Donated Organ Procurement, Hubei Key Laboratory of Medical Technology on Transplantation, Hubei Clinical Research Center for Natural Polymer Biological Liver, Hubei Engineering Center of Natural Polymer-Based Medical Materials, Zhongnan Hospital of Wuhan University, Institute of Hepatobiliary Diseases of Wuhan University, Transplant Center of Wuhan University, Wuhan, Hubei, China
| | - Ting Chen
- Department of Dermatology, Wuhan Third Hospital and Tongren Hospital of Wuhan University, Wuhan, Hubei, China
| | - Yiwen Chen
- Department of Hepatobiliary Surgery, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Cong-Yi Wang
- The Center for Biomedical Research, NHC Key Laboratory of Respiratory Diseases, Department of Respiratory and Critical Care Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences and Technology, Wuhan, Hubei, China.
| | - Zhongzhong Liu
- National Quality Control Center for Donated Organ Procurement, Hubei Key Laboratory of Medical Technology on Transplantation, Hubei Clinical Research Center for Natural Polymer Biological Liver, Hubei Engineering Center of Natural Polymer-Based Medical Materials, Zhongnan Hospital of Wuhan University, Institute of Hepatobiliary Diseases of Wuhan University, Transplant Center of Wuhan University, Wuhan, Hubei, China.
| | - Qifa Ye
- National Quality Control Center for Donated Organ Procurement, Hubei Key Laboratory of Medical Technology on Transplantation, Hubei Clinical Research Center for Natural Polymer Biological Liver, Hubei Engineering Center of Natural Polymer-Based Medical Materials, Zhongnan Hospital of Wuhan University, Institute of Hepatobiliary Diseases of Wuhan University, Transplant Center of Wuhan University, Wuhan, Hubei, China; Research Center of National Health Ministry on Transplantation Medicine Engineering and Technology, The 3rd Xiangya Hospital of Central South University, Changsha, Hunan, China.
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2
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Mudrich M, LaForge AC, Ciavardini A, O'Keeffe P, Callegari C, Coreno M, Demidovich A, Devetta M, Fraia MD, Drabbels M, Finetti P, Gessner O, Grazioli C, Hernando A, Neumark DM, Ovcharenko Y, Piseri P, Plekan O, Prince KC, Richter R, Ziemkiewicz MP, Möller T, Eloranta J, Pi M, Barranco M, Stienkemeier F. Ultrafast relaxation of photoexcited superfluid He nanodroplets. Nat Commun 2020; 11:112. [PMID: 31913265 PMCID: PMC6949273 DOI: 10.1038/s41467-019-13681-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Accepted: 11/19/2019] [Indexed: 11/23/2022] Open
Abstract
The relaxation of photoexcited nanosystems is a fundamental process of light–matter interaction. Depending on the couplings of the internal degrees of freedom, relaxation can be ultrafast, converting electronic energy in a few fs, or slow, if the energy is trapped in a metastable state that decouples from its environment. Here, we study helium nanodroplets excited resonantly by femtosecond extreme-ultraviolet (XUV) pulses from a seeded free-electron laser. Despite their superfluid nature, we find that helium nanodroplets in the lowest electronically excited states undergo ultrafast relaxation. By comparing experimental photoelectron spectra with time-dependent density functional theory simulations, we unravel the full relaxation pathway: Following an ultrafast interband transition, a void nanometer-sized bubble forms around the localized excitation (He\documentclass[12pt]{minimal}
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\begin{document}$${}^{* }$$\end{document}*) within 1 ps. Subsequently, the bubble collapses and releases metastable He\documentclass[12pt]{minimal}
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\begin{document}$${}^{* }$$\end{document}* at the droplet surface. This study highlights the high level of detail achievable in probing the photodynamics of nanosystems using tunable XUV pulses. There is interest in understanding the relaxation mechanisms of photoexcitation in atoms, molecules and other complex systems. Here the authors unravel the photoexcitation and ultrafast relaxation of superfluid helium nanodroplets using a pump-probe experiment with FEL pulses.
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Affiliation(s)
- M Mudrich
- Department of Physics and Astronomy, Aarhus University, Aarhus C, 8000, Denmark.
| | - A C LaForge
- Institute of Physics, University of Freiburg, Freiburg im Breisgau, 79104, Germany.,Department of Physics, University of Connecticut, Storrs, CT, 06269, USA
| | - A Ciavardini
- CNR-ISM, Area della Ricerca di Roma 1, Monterotondo Scalo, 00015, Italy.,CERIC-ERIC Basovizza, Trieste, 34149, Italy
| | - P O'Keeffe
- CNR-ISM, Area della Ricerca di Roma 1, Monterotondo Scalo, 00015, Italy
| | - C Callegari
- Elettra - Sincrotrone Trieste S.C.p.A., Basovizza, Trieste, 34149, Italy
| | - M Coreno
- CNR-ISM, Area della Ricerca di Roma 1, Monterotondo Scalo, 00015, Italy
| | - A Demidovich
- Elettra - Sincrotrone Trieste S.C.p.A., Basovizza, Trieste, 34149, Italy
| | - M Devetta
- Dipartimento di Fisica, Università degli Studi di Milano, Milan, 20133, Italy.,CNR-IFN, Milano, 20133, Italy
| | - M Di Fraia
- Elettra - Sincrotrone Trieste S.C.p.A., Basovizza, Trieste, 34149, Italy
| | - M Drabbels
- Laboratory of Molecular Nanodynamics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015, Switzerland
| | - P Finetti
- Elettra - Sincrotrone Trieste S.C.p.A., Basovizza, Trieste, 34149, Italy
| | - O Gessner
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - C Grazioli
- CNR-IOM, Istituto Officina dei Materiali, Area Science Park - Basovizza, Trieste, 34149, Italy
| | - A Hernando
- Kido Dynamics, EPFL Innovation Park Bat. C, 1015, Lausanne, Switzerland.,IFISC (CSIC-UIB), Instituto de Fisica Interdisciplinar y Sistemas Complejos, Campus Universitat de les Illes Balears, 07122, Palma de Mallorca, Spain
| | - D M Neumark
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - Y Ovcharenko
- Institut für Optik und Atomare Physik, TU-Berlin, 10623, Germany.,European XFEL, Schenefeld, 22869, Germany
| | - P Piseri
- Dipartimento di Fisica, Università degli Studi di Milano, Milan, 20133, Italy
| | - O Plekan
- Elettra - Sincrotrone Trieste S.C.p.A., Basovizza, Trieste, 34149, Italy
| | - K C Prince
- Elettra - Sincrotrone Trieste S.C.p.A., Basovizza, Trieste, 34149, Italy
| | - R Richter
- Elettra - Sincrotrone Trieste S.C.p.A., Basovizza, Trieste, 34149, Italy
| | - M P Ziemkiewicz
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - T Möller
- Institut für Optik und Atomare Physik, TU-Berlin, 10623, Germany
| | - J Eloranta
- Department of Chemistry and Biochemistry, California State University at Northridge, Northridge, CA, 91330, USA
| | - M Pi
- Departament FQA, Facultat de Física, Universitat de Barcelona, Barcelona, 08028, Spain.,Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, 08028, Spain
| | - M Barranco
- Departament FQA, Facultat de Física, Universitat de Barcelona, Barcelona, 08028, Spain.,Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, 08028, Spain.,Laboratoire des Collisions, Agrégats, Réactivité, IRSAMC, UMR 5589, CNRS et Université Paul Sabatier-Toulouse 3, Toulouse, Cedex 09, 31062, France
| | - F Stienkemeier
- Institute of Physics, University of Freiburg, Freiburg im Breisgau, 79104, Germany
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3
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von Vangerow J, Sieg A, Stienkemeier F, Mudrich M, Leal A, Mateo D, Hernando A, Barranco M, Pi M. Desorption Dynamics of Heavy Alkali Metal Atoms (Rb, Cs) Off the Surface of Helium Nanodroplets. J Phys Chem A 2014; 118:6604-14. [DOI: 10.1021/jp503308w] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. von Vangerow
- Physikalisches
Institut, Universität Freiburg, 79104 Freiburg, Germany
| | - A. Sieg
- Physikalisches
Institut, Universität Freiburg, 79104 Freiburg, Germany
| | - F. Stienkemeier
- Physikalisches
Institut, Universität Freiburg, 79104 Freiburg, Germany
| | - M. Mudrich
- Physikalisches
Institut, Universität Freiburg, 79104 Freiburg, Germany
| | - A. Leal
- Departament
ECM, Facultat de Física and IN2UB, Universitat de Barcelona, 08028 Barcelona, Spain
| | - D. Mateo
- Departament
ECM, Facultat de Física and IN2UB, Universitat de Barcelona, 08028 Barcelona, Spain
- Department
of Chemistry and Biochemistry, California State University at Northridge, 18111 Nordhoff Street, Northridge, California 91330, United States
| | - A. Hernando
- Laboratoire
de Chimie Physique Moléculaire, Swiss Federal Institute of Technology Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - M. Barranco
- Departament
ECM, Facultat de Física and IN2UB, Universitat de Barcelona, 08028 Barcelona, Spain
| | - M. Pi
- Departament
ECM, Facultat de Física and IN2UB, Universitat de Barcelona, 08028 Barcelona, Spain
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4
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Abstract
A finite-temperature density functional approach to describe the properties of parahydrogen in the liquid-vapor coexistence region is presented. The first proposed functional is zero-range, where the density-gradient term is adjusted so as to reproduce the surface tension of the liquid-vapor interface at low temperature. The second functional is finite-range and, while it is fitted to reproduce bulk pH(2) properties only, it is shown to yield surface properties in good agreement with experiments. These functionals are used to study the surface thickness of the liquid-vapor interface, the wetting transition of parahydrogen on a planar Rb model surface, and homogeneous cavitation in bulk liquid pH(2).
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Affiliation(s)
- J Navarro
- IFIC (CSIC and Universidad de Valencia), Apdo. 22085, 46071 Valencia, Spain
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5
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Affiliation(s)
- F. Ancilotto
- INFM-CNR DEMOCRITOS National Simulation Center and Dipartimento di Fisica “G. Galilei”, Università di Padova, via Marzolo 8, I-35131 Padova, Italy, Departament ECM, Facultat de Física, and IN2UB, Universitat de Barcelona. Diagonal 647, 08028 Barcelona, Spain, and Departament of Chemistry and Physics, University of Virginia, 22904-4319 Charlottesville, Virginia
| | - M. Pi
- INFM-CNR DEMOCRITOS National Simulation Center and Dipartimento di Fisica “G. Galilei”, Università di Padova, via Marzolo 8, I-35131 Padova, Italy, Departament ECM, Facultat de Física, and IN2UB, Universitat de Barcelona. Diagonal 647, 08028 Barcelona, Spain, and Departament of Chemistry and Physics, University of Virginia, 22904-4319 Charlottesville, Virginia
| | - R. Mayol
- INFM-CNR DEMOCRITOS National Simulation Center and Dipartimento di Fisica “G. Galilei”, Università di Padova, via Marzolo 8, I-35131 Padova, Italy, Departament ECM, Facultat de Física, and IN2UB, Universitat de Barcelona. Diagonal 647, 08028 Barcelona, Spain, and Departament of Chemistry and Physics, University of Virginia, 22904-4319 Charlottesville, Virginia
| | - M. Barranco
- INFM-CNR DEMOCRITOS National Simulation Center and Dipartimento di Fisica “G. Galilei”, Università di Padova, via Marzolo 8, I-35131 Padova, Italy, Departament ECM, Facultat de Física, and IN2UB, Universitat de Barcelona. Diagonal 647, 08028 Barcelona, Spain, and Departament of Chemistry and Physics, University of Virginia, 22904-4319 Charlottesville, Virginia
| | - K. K. Lehmann
- INFM-CNR DEMOCRITOS National Simulation Center and Dipartimento di Fisica “G. Galilei”, Università di Padova, via Marzolo 8, I-35131 Padova, Italy, Departament ECM, Facultat de Física, and IN2UB, Universitat de Barcelona. Diagonal 647, 08028 Barcelona, Spain, and Departament of Chemistry and Physics, University of Virginia, 22904-4319 Charlottesville, Virginia
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6
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Mayol R, Barranco M, Hernández ES, Pi M, Guilleumas M. Bound states of 3He at the edge of a 4He drop on a cesium surface. Phys Rev Lett 2003; 90:185301. [PMID: 12786017 DOI: 10.1103/physrevlett.90.185301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2002] [Indexed: 05/24/2023]
Abstract
We show that small amounts of 3He atoms, added to a 4He drop deposited on a flat cesium surface at zero temperature, populate bound states localized at the contact line. These edge states show up for drops large enough to develop well defined surface and bulk regions together with a contact line, and they are structurally different from the well-known Andreev states that appear at the free surface and at the liquid-solid interface of films. We illustrate the one-body density of 3He in a drop with 1000 4He atoms, and show that for a sufficiently large number of impurities the density profiles spread beyond the edge, coating both the curved drop surface and its flat base and eventually isolating it from the substrate.
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Affiliation(s)
- R Mayol
- Departament ECM, Facultat de Física, Universitat de Barcelona, E-08028 Barcelona, Spain
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7
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Abstract
Using density functional theory, we investigate the structure of mixed (3)He(N3)-(4)He(N4) droplets with an embedded impurity (Xe atom or HCN molecule) which pins a quantized vortex line. We find that the dopant+vortex+(4)He(N4) complex, which in a previous work [F. Dalfovo et al., Phys. Rev. Lett. 85, 1028 (2000)] was found to be energetically stable below a critical size N(cr), is robust against the addition of 3He. While 3He atoms are distributed along the vortex line and on the surface of the 4He drop, the impurity is mostly coated by 4He atoms. Results for N4 = 500 and a number of 3He atoms ranging from 0 to 100 are presented, and the binding energy of the dopant to the vortex line is determined.
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Affiliation(s)
- R Mayol
- Departament ECM, Facultat de Física, Universitat de Barcelona, E-08028 Barcelona, Spain
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8
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Abstract
The hypothesis that local changes in extracellular calcium may serve a physiological role in regulating osteoblast, osteoclast, and cartilage function through the extracellular cation-sensing receptor, CasR, is gaining widespread support, but lacks definite proof. To examine the effects of CasR deficiency on the skeleton, we performed a detailed analysis of the skeleton in CasR knockout mice (CasR(-/-)) and wild-type littermates (CasR(+/+)). CasR ablation in the parathyroid glands of CasR(-/-) mice resulted in hyperparathyroidism, hypercalcemia, and hypophosphatemia. Except for dwarfism, the expected skeletal manifestations of PTH excess, namely chondrodysplasia and increased mineralized bone formation and resorption, were not the main skeletal features in CasR(-/-) mice. Rather, rickets was the predominant skeletal abnormality in these animals, as evidenced by a widened zone of hypertrophic chondrocytes, impaired growth plate calcification and disorderly deposition of mineral, excessive osteoid accumulation, and prolonged mineralization lag time in metaphyseal bone. CasR transcripts were identified in cartilage and bone marrow of CasR(+/+) mice, but not in mineralized bone containing mature osteoblasts and osteocytes. These findings indicate that a calcium-sensing receptor is present in the skeleton, and its absence results in defective mineralization of cartilage and bone by mechanisms that remain to be elucidated.
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Affiliation(s)
- S C Garner
- Division of Nephrology, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
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9
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Pi M, Emperador A, Barranco M, Garcias F, Muraki K, Tarucha S, Austing DG. Dissociation of vertical semiconductor diatomic artificial molecules. Phys Rev Lett 2001; 87:066801. [PMID: 11497840 DOI: 10.1103/physrevlett.87.066801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2001] [Indexed: 05/23/2023]
Abstract
We investigate the dissociation of few-electron circular vertical semiconductor double quantum dot artificial molecules at 0 T as a function of interdot distance. A slight mismatch introduced in the fabrication of the artificial molecules from nominally identical constituent quantum wells induces localization by offsetting the energy levels in the quantum dots by up to 2 meV, and this plays a crucial role in the appearance of the addition energy spectra as a function of coupling strength particularly in the weak coupling limit.
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Affiliation(s)
- M Pi
- Departament ECM, Facultat de Física, Universitat de Barcelona, E-08028 Barcelona, Spain
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10
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Abstract
This paper presents a new adaptive search approach to reduce the computational complexity of fractal encoding. A simple but very efficient adaptive necessary condition is introduced to exclude a large number of unqualified domain blocks so as to speed-up fractal image compression. Furthermore, we analyzed an unconventional affine parameter that has better properties than the conventional luminance offset. Specifically, we formulated an optimal bit allocation scheme for the simultaneous quantizations of the usual scaling and the aforementioned unconventional affine parameter. Experiments on standard images showed that our adaptive search method yields superior performance over conventional fractal encoding.
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Affiliation(s)
- C S Tong
- Dept. of Math., Hong Kong Baptist Univ.
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11
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Dalfovo F, Mayol R, Pi M, Barranco M. Pinning of quantized vortices in helium drops by dopant atoms and molecules. Phys Rev Lett 2000; 85:1028-1031. [PMID: 10991466 DOI: 10.1103/physrevlett.85.1028] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/1999] [Indexed: 05/23/2023]
Abstract
Using a density functional method, we investigate the properties of liquid 4He droplets doped with atoms (Ne and Xe) and molecules ( SF6 and hydrogen cyanide). We consider the case of droplets having a quantized vortex pinned to the dopant. A liquid-drop formula is proposed that accurately describes the total energy of the complex and allows one to extrapolate the density functional results to large N. For a given impurity, we find that the formation of a dopant+vortex+(4)He(N) complex is energetically favored below a critical size N(cr). Our results support the possibility to observe quantized vortices in helium droplets by means of spectroscopic techniques.
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Affiliation(s)
- F Dalfovo
- Dipartimento di Matematica e Fisica, Universita Cattolica, Via Musei 41, I-25121 Brescia, Italy and and Istituto Nazionale per la Fisica della Materia, Unita di Trento, I-38050 Povo, Italy
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12
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Ogawa S, Yoshino R, Angata K, Iwamoto M, Pi M, Kuroe K, Matsuo K, Morio T, Urushihara H, Yanagisawa K, Tanaka Y. The mitochondrial DNA of Dictyostelium discoideum: complete sequence, gene content and genome organization. Mol Gen Genet 2000; 263:514-9. [PMID: 10821186 DOI: 10.1007/pl00008685] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We present an overview of the gene content and organization of the mitochondrial genome of Dictyostelium discoideum. The mitochondria genome consists of 55,564 bp with an A + T content of 72.6%. The identified genes include those for two ribosomal RNAs (rn1 and rns), 18 tRNAs, ten subunits of the NADH dehydrogenase complex (nad1, 2, 3, 4, 4L, 5, 6, 7, 9 and 11), apocytochrome b (cytb), three subunits of the cytochrome oxidase (cox1/2 and 3), four subunits of the ATP synthase complex (atp1, 6, 8 and 9), 15 ribosomal proteins, and five other ORFs, excluding intronic ORFs. Notable features of D. discoideum mtDNA include the following. (1) All genes are encoded on the same strand of the DNA and a universal genetic code is used. (2) The cox1 gene has no termination codon and is fused to the downstream cox2 gene. The 13 genes for ribosomal proteins and four ORF genes form a cluster 15.4 kb long with several gene overlaps. (3) The number of tRNAs encoded in the genome is not sufficient to support the synthesis of mitochondrial protein. (4) In total, five group I introns reside in rnl and cox1/2, and three of those in cox1/2 contain four free-standing ORFs. We compare the genome to other sequenced mitochondrial genomes, particularly that of Acanthamoeba castellanii.
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Affiliation(s)
- S Ogawa
- Institute of Biological Sciences, Ibaraki, Japan
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13
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Pi M, Garner SC, Flannery P, Spurney RF, Quarles LD. Sensing of extracellular cations in CasR-deficient osteoblasts. Evidence for a novel cation-sensing mechanism. J Biol Chem 2000; 275:3256-63. [PMID: 10652312 DOI: 10.1074/jbc.275.5.3256] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We isolated osteoblastic cell lines from wild-type (CasR(+/+)) and receptor null (CasR(-/-)) mice to investigate whether CasR is present in osteoblasts and accounts for their responses to extracellular cations. Osteoblasts from both CasR(+/+) and CasR(-/-) mice displayed an initial period of cell replication followed by a culture duration-dependent increase in alkaline phosphatase activity, expression of osteocalcin, and mineralization of extracellular matrix. In addition, a panel of extracellular cations, including aluminum and the CasR agonists gadolinium and calcium, stimulated DNA synthesis, activated a transfected serum response element-luciferase reporter construct, and inhibited agonist-induced cAMP in CasR(-/-) osteoblasts. The functional responses to these cations were identical in CasR(+/+) and CasR(-/-) osteoblasts. Thus, the absence of CasR alters neither the maturational profile of isolated osteoblast cultures nor their in vitro responses to extracellular cations. In addition, CasR transcripts could not be detected by reverse transcription-polymerase chain reaction with mouse specific primers in either CasR(+/+) or CasR(-/-) osteoblasts, and immunoblot analysis with a CasR-specific antibody was negative for CasR protein expression in osteoblasts. The presence of a cation-sensing response in osteoblasts from CasR(-/-) mice indicates the existence of a novel osteoblastic extracellular cation-sensing mechanism.
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Affiliation(s)
- M Pi
- Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
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14
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Abstract
Whether the known calcium-sensing receptor (CasR) is present in osteoblasts is a source of considerable controversy. Prior studies failed to detect CasR in osteoblasts, but more recent investigations purport the detection of CasR in several osteoblast cell lines by immunoblot analysis with polyclonal anti-CasR antisera (4637) and low stringency reverse transcriptase-polymerase chain reaction (RT-PCR). To explain these disparate findings, we performed immunoblot analysis with the 4637 anti-CasR antisera and a highly specific monoclonal antibody to CasR (ADD), and we compared the ability of low and high stringency RT-PCR to amplify CasR transcripts. We found that the ADD antibody detected the anticipated CasR immunoreactive bands, including a approximately 165 kDa and approximately 140 kDa glycosylated doublet and a >250 kDa dimerized receptor, in positive control mouse kidney, human parathyroid, and human embryonic kidney (HEK) 293 cells transfected with rat CasR, but we did not detect these bands in either wild-type HEK 293 cells or Saos2, MG-63, or U-2 OS osteoblast-like cell lines. Standard two-step RT-PCR using CasR-specific primers confirmed these results by detecting CasR transcripts in positive controls but not in negative control HEK 293 cells or osteoblast cell lines. In contrast, the 4637 antisera did not recognize CasR by immunoblot analysis under the conditions studied and our low stringency RT-PCR procedure amplified nonspecific products in wild-type HEK 293 cells and osteoblasts. Since we failed to detect CasR in human osteoblast cell lines using either the highly specific ADD antibody or RT-PCR under standard conditions, it is possible that the cation response in osteoblasts is mediated by a functionally similar but molecularly distinct calcium sensing receptor.
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Affiliation(s)
- M Pi
- Duke University Medical Center, Durham, North Carolina 27710, USA
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Abstract
BACKGROUND Aluminum (Al3+) has diverse biological effects mediated through activation of a putative extracellular cation-sensing receptor. A recently identified calcium-sensing receptor (CaSR), which has been identified in target tissues for Al3+, may transduce some of the biological effects of Al3+. METHODS To test this possibility, we transfected human embryonic kidney 293 (HEK 293) cells with a cDNA encoding the rat CaSR and evaluated CaSR expression by Western blot analysis and function by measurement of intracellular calcium ([Ca2+]i) levels and inositol monophosphate (IP1) generation following stimulation with Al3+ and a panel of CaSR agonists. RESULTS The CaSR protein was detected by immunoblot analysis in cells transfected with the CaSR cDNA but not in nontransfected HEK 293 cells. In addition, [Ca2+]i levels and IP1 generation were enhanced in a dose-dependent fashion by additions of the CaSR agonists calcium (Ca2+), magnesium (Mg2+), gadolinium (Gd3+), and neomycin only in cells transfected with CaSR. To determine if Al3+ activated CaSR, we stimulated cells transfected with rat CaSR with 10 microM to 1 mM concentrations of Al3+. Concentrations of Al3+ in the range of 10 microM to 100 microM had no effect on [Ca2+]i levels or IP1 generation. In contrast, 1 mM Al3+ induced small but significant increases in both parameters. Whereas Gd3+ antagonized calcium-mediated activation of CaSR, pretreatment with Al3+ failed to block subsequent activation of rat CaSR by Ca2+, suggesting a distinct mechanism of Al3+ action. CONCLUSION Al3+ is not a potent agonist for CaSR. Because Al3+ affects a variety of target tissues at micromolar concentrations, it seems unlikely that CaSR mediates these cellular actions of Al3+.
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Affiliation(s)
- R F Spurney
- Duke University Medical Center, Durham, North Carolina, USA
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Morio T, Urushihara H, Saito T, Ugawa Y, Mizuno H, Yoshida M, Yoshino R, Mitra BN, Pi M, Sato T, Takemoto K, Yasukawa H, Williams J, Maeda M, Takeuchi I, Ochiai H, Tanaka Y. The Dictyostelium developmental cDNA project: generation and analysis of expressed sequence tags from the first-finger stage of development. DNA Res 1998; 5:335-40. [PMID: 10048482 DOI: 10.1093/dnares/5.6.335] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In an effort to identify and characterize genes expressed during multicellular development ill Dictyostelium, we have undertaken a cDNA sequencing project. Using size-fractionated subsets of cDNA from the first finger stage, two sets of gridded libraries were constructed for cDNA sequencing. One, library S, consisting of 9984 clones, carries relatively short inserts, and the other, library L, which consists of 8448 clones, has longer inserts. We sequenced all the selected clones in library S from their 3'-ends, and this generated 3093 non-redundant, expressed sequence tags (ESTs). Among them, 246 ESTs hit known Dictyostelium genes and 910 showed significant similarity to genes of Dictyostelium and other organisms. For library L, 1132 clones were randomly sequenced and 471 non-redundant ESTs were obtained. In combination, the ESTs from the two libraries represent approximately 40% of genes expressed in late development, assuming that the non-redundant ESTs correspond to independent genes. They will provide a useful resource for investigating the genetic networks that regulate multicellular development of this organism.
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Affiliation(s)
- T Morio
- Institute of Biological Sciences, Univ., Tsukuba, Ibaraki, Japan
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Iwamoto M, Pi M, Kurihara M, Morio T, Tanaka Y. A ribosomal protein gene cluster is encoded in the mitochondrial DNA of Dictyostelium discoideum: UGA termination codons and similarity of gene order to Acanthamoeba castellanii. Curr Genet 1998; 33:304-10. [PMID: 9560439 DOI: 10.1007/s002940050341] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We sequenced a region of about 14.5 kb downstream from the ribosomal protein L11 gene (rpl11) in the mitochondrial DNA (54+/-2 kb) of the cellular slime mold Dictyostelium discoideum. Sequence analysis revealed that eleven ribosomal protein genes and six open reading frames (ORFs) formed a cluster arranged in the order: rpl11-orf189-rps12-rps7-rpl2-rps19-+ ++orf425-orf1740-rpl16-rpl14-orf188- rps14-rps8-rpl6-rps13-orf127-orf796. This order was very similar to that of homologous genes in Acanthamoeba castellanii mitochondrial DNA. The N-terminal region of ORF425 and the C-terminal region of ORF1740 had partial similarities to the S3 ribosomal protein of other organisms. The termination codons of rpl16 and orf188 were UGA, which has not hitherto been found in genes encoded in D. discoideum mitochondrial DNA.
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Affiliation(s)
- M Iwamoto
- Institute of Biological Sciences, University of Tsukuba, Japan
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Pi M, Morio T, Urushihara H, Tanaka Y. Characterization of a novel small RNA encoded by Dictyostelium discoideum mitochondrial DNA. Mol Gen Genet 1998; 257:124-31. [PMID: 9491070 DOI: 10.1007/s004380050631] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In this study, we analyzed a mitochondrial small (ms) RNA in Dictyostelium discoideum, which is 129 nucleotides long and has a GC content of only 22.5%. In the mitochondrial DNA, a single-copy gene (msr) for the ms RNA was located downstream of the gene for large-subunit rRNA. The location of msr was similar to that of the 5S rRNA gene in prokaryotes and chloroplasts, but clearly different from that in mitochondria of plants, liverwort and the chlorophycean alga Prototheca wikerhamii, in which small-subunit rRNA and 5S rRNA genes are closely linked. THe primary sequence of ms rRNA showed low homology with mitochondrial 5S rRNA from plants, liverwort and the chlorophycean alga, but the proposed secondary structure of ms RNA was similar to that of cytoplasmic 5S rRNA. In addition, ms RNA showed a highly conserved GAAC sequence in the same loop as in common 5S rRNA. However, ms RNA was detected mainly in the mitochondrial 25,000 x g supernatant fraction which was devoid of ribosomes. It is possible that ms RNA is an evolutionary derivative of mitochondrial 5S rRNA.
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Affiliation(s)
- M Pi
- Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan
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Guilleumas M, Barranco M, Jezek DM, Lombard RJ, Pi M. Quantum cavitation in liquid helium. Phys Rev B Condens Matter 1996; 54:16135-16138. [PMID: 9985689 DOI: 10.1103/physrevb.54.16135] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Guilleumas M, Pi M, Barranco M, Jezek DM, Navarro J. Nucleation in supersaturated solutions of 3He in 4He at negative pressures. Phys Rev B Condens Matter 1995; 52:1210-1214. [PMID: 9980701 DOI: 10.1103/physrevb.52.1210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Jezek DM, Guilleumas M, Pi M, Barranco M. Critical supersaturation of 3He-4He liquid mixtures at low temperatures. Phys Rev B Condens Matter 1995; 51:11981-11983. [PMID: 9977949 DOI: 10.1103/physrevb.51.11981] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Barberán N, Pi M. Static polarizability associated with multipole surface plasmons in metallic surfaces. Phys Rev B Condens Matter 1995; 51:7329-7332. [PMID: 9977305 DOI: 10.1103/physrevb.51.7329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Guilleumas M, Jezek DM, Pi M, Barranco M, Navarro J. Cavitation in 3He-4He liquid mixtures at low temperatures. Phys Rev B Condens Matter 1995; 51:1140-1146. [PMID: 9978268 DOI: 10.1103/physrevb.51.1140] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Jezek DM, Guilleumas M, Pi M, Barranco M, Navarro J. Thermal nucleation and cavitation in 3He and 4He. Phys Rev B Condens Matter 1993; 48:16582-16588. [PMID: 10008242 DOI: 10.1103/physrevb.48.16582] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Guilleumas M, Pi M, Barranco M, Navarro J, Solís MA. Thermal nucleation of cavities in liquid helium at negative pressures. Phys Rev B Condens Matter 1993; 47:9116-9119. [PMID: 10004968 DOI: 10.1103/physrevb.47.9116] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Abstract
Wave-front matching of the local oscillator beam and the signal beam is of vital importance in optical heterodyne efficiency. A method for aligning the local oscillator beam and the signal beam is described. Mixing efficiency is improved. One can directly observe the matching procedure on an oscilloscope.
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Serra L, Garcías F, Navarro J, Barberán N, Barranco M, Pi M. Electronic surface excitations of cavities in metals. Phys Rev B Condens Matter 1992; 46:9369-9379. [PMID: 10002741 DOI: 10.1103/physrevb.46.9369] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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