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Liu H, Zhang Y, Yip M, Ren L, Liang J, Chen X, Liu N, Du A, Wang J, Chang H, Oh H, Zhou C, Xing R, Xu M, Guo P, Gessler D, Xie J, Tai PW, Gao G, Wang D. Producing high-quantity and high-quality recombinant adeno-associated virus by low-cis triple transfection. Mol Ther Methods Clin Dev 2024; 32:101230. [PMID: 38558570 PMCID: PMC10979107 DOI: 10.1016/j.omtm.2024.101230] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 03/08/2024] [Indexed: 04/04/2024]
Abstract
Recombinant adeno-associated virus (rAAV)-based gene therapy is entering clinical and commercial stages at an unprecedented pace. Triple transfection of HEK293 cells is currently the most widely used platform for rAAV manufacturing. Here, we develop low-cis triple transfection that decreases transgene plasmid use by 10- to 100-fold and overcomes several major limitations associated with standard triple transfection. This new method improves packaging of yield-inhibiting transgenes by up to 10-fold, and generates rAAV batches with reduced plasmid backbone contamination that otherwise cannot be eliminated in downstream processing. When tested in mice and compared with rAAV produced by standard triple transfection, low-cis rAAV shows comparable or superior potency and results in diminished plasmid backbone DNA and RNA persistence in tissue. Mechanistically, low-cis triple transfection relies on the extensive replication of transgene cassette (i.e., inverted terminal repeat-flanked vector DNA) in HEK293 cells during production phase. This cost-effective method can be easily implemented and is widely applicable to producing rAAV of high quantity, purity, and potency.
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Affiliation(s)
- Hao Liu
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Yue Zhang
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Mitchell Yip
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Lingzhi Ren
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Jialing Liang
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Xiupeng Chen
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Nan Liu
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Ailing Du
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Jiaming Wang
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Hao Chang
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Hyejin Oh
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Chen Zhou
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Ruxiao Xing
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Mengyao Xu
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Peiyi Guo
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Dominic Gessler
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Jun Xie
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Phillip W.L. Tai
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Guangping Gao
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Dan Wang
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
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2
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Xie Q, Chen X, Ma H, Zhu Y, Ma Y, Jalinous L, Cox GF, Weaver F, Yang J, Kennedy Z, Gruntman A, Du A, Su Q, He R, Tai PW, Gao G, Xie J. Improved gene therapy for spinal muscular atrophy in mice using codon-optimized hSMN1 transgene and hSMN1 gene-derived promotor. EMBO Mol Med 2024; 16:945-965. [PMID: 38413838 PMCID: PMC11018631 DOI: 10.1038/s44321-024-00037-x] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 02/29/2024] Open
Abstract
Physiological regulation of transgene expression is a major challenge in gene therapy. Onasemnogene abeparvovec (Zolgensma®) is an approved adeno-associated virus (AAV) vector gene therapy for infants with spinal muscular atrophy (SMA), however, adverse events have been observed in both animals and patients following treatment. The construct contains a native human survival motor neuron 1 (hSMN1) transgene driven by a strong, cytomegalovirus enhancer/chicken β-actin (CMVen/CB) promoter providing high, ubiquitous tissue expression of SMN. We developed a second-generation AAV9 gene therapy expressing a codon-optimized hSMN1 transgene driven by a promoter derived from the native hSMN1 gene. This vector restored SMN expression close to physiological levels in the central nervous system and major systemic organs of a severe SMA mouse model. In a head-to-head comparison between the second-generation vector and a benchmark vector, identical in design to onasemnogene abeparvovec, the 2nd-generation vector showed better safety and improved efficacy in SMA mouse model.
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Affiliation(s)
- Qing Xie
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
| | - Xiupeng Chen
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
| | - Hong Ma
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Viral Vector Core, UMass Chan Medical School, Worcester, MA, USA
| | | | - Yijie Ma
- CANbridge Pharmaceuticals, Burlington, MA, USA
| | | | | | | | - Jun Yang
- CANbridge Pharmaceuticals, Burlington, MA, USA
| | | | - Alisha Gruntman
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Pediatrics, UMass Chan Medical School, Worcester, MA, USA
| | - Ailing Du
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
| | - Qin Su
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
- Viral Vector Core, UMass Chan Medical School, Worcester, MA, USA
| | - Ran He
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
- Viral Vector Core, UMass Chan Medical School, Worcester, MA, USA
| | - Phillip Wl Tai
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
- Li Weibo Institute for Rare Diseases Research, UMass Chan Medical School, Worcester, MA, USA
| | - Guangping Gao
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA.
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA.
- Li Weibo Institute for Rare Diseases Research, UMass Chan Medical School, Worcester, MA, USA.
| | - Jun Xie
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA.
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA.
- Viral Vector Core, UMass Chan Medical School, Worcester, MA, USA.
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Chang H, Du A, Jiang J, Ren L, Liu N, Zhou X, Liang J, Gao G, Wang D. Non-canonical amino acid incorporation into AAV5 capsid enhances lung transduction in mice. Mol Ther Methods Clin Dev 2023; 31:101129. [PMID: 37886602 PMCID: PMC10597788 DOI: 10.1016/j.omtm.2023.101129] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 10/04/2023] [Indexed: 10/28/2023]
Abstract
Gene therapy using recombinant adeno-associated virus (rAAV) relies on safe, efficient, and precise in vivo gene delivery that is largely dependent on the AAV capsid. The proteinaceous capsid is highly amenable to engineering using a variety of approaches, and most resulting capsids carry substitutions or insertions comprised of natural amino acids. Here, we incorporated a non-canonical amino acid (ncAA), Nε-2-azideoethyloxycarbonyl-L-lysine (also known as NAEK), into the AAV5 capsid using genetic code expansion, and serendipitously found that several NAEK-AAV5 vectors transduced various cell lines more efficiently than the parental rAAV5. Furthermore, one NAEK-AAV5 vector showed lung-specific transduction enhancement following systemic or intranasal delivery in mice. Structural modeling suggests that the long side chain of NAEK may impact on the 3-fold protrusion on the capsid surface that plays a key role in tropism, thereby modulating vector transduction. Recent advances in genetic code expansion have generated synthetic proteins carrying an increasing number of ncAAs that possess diverse biological properties. Our study suggests that ncAA incorporation into the AAV capsid may confer novel vector properties, opening a new and complementary avenue to gene therapy vector discovery.
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Affiliation(s)
- Hao Chang
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Ailing Du
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Jun Jiang
- GeneLeap Bio, Luye Life Sciences, Woburn, MA 01801, USA
| | - Lingzhi Ren
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Nan Liu
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Xuntao Zhou
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Jialing Liang
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Guangping Gao
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Dan Wang
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
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4
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Arbab M, Matuszek Z, Kray KM, Du A, Newby GA, Blatnik AJ, Raguram A, Richter MF, Zhao KT, Levy JM, Shen MW, Arnold WD, Wang D, Xie J, Gao G, Burghes AHM, Liu DR. Base editing rescue of spinal muscular atrophy in cells and in mice. Science 2023; 380:eadg6518. [PMID: 36996170 PMCID: PMC10270003 DOI: 10.1126/science.adg6518] [Citation(s) in RCA: 38] [Impact Index Per Article: 38.0] [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] [Received: 01/11/2023] [Accepted: 03/21/2023] [Indexed: 04/01/2023]
Abstract
Spinal muscular atrophy (SMA), the leading genetic cause of infant mortality, arises from survival motor neuron (SMN) protein insufficiency resulting from SMN1 loss. Approved therapies circumvent endogenous SMN regulation and require repeated dosing or may wane. We describe genome editing of SMN2, an insufficient copy of SMN1 harboring a C6>T mutation, to permanently restore SMN protein levels and rescue SMA phenotypes. We used nucleases or base editors to modify five SMN2 regulatory regions. Base editing converted SMN2 T6>C, restoring SMN protein levels to wild type. Adeno-associated virus serotype 9-mediated base editor delivery in Δ7SMA mice yielded 87% average T6>C conversion, improved motor function, and extended average life span, which was enhanced by one-time base editor and nusinersen coadministration (111 versus 17 days untreated). These findings demonstrate the potential of a one-time base editing treatment for SMA.
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Affiliation(s)
- Mandana Arbab
- Department of Neurology, Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA 02115, USA
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Zaneta Matuszek
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Kaitlyn M. Kray
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Columbus, OH 43210, USA
| | - Ailing Du
- Horae Gene Therapy Center, University of Massachusetts, Medical School, Worcester, MA 01605, USA
| | - Gregory A. Newby
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Anton J. Blatnik
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Columbus, OH 43210, USA
| | - Aditya Raguram
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Michelle F. Richter
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Kevin T. Zhao
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Jonathan M. Levy
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Max W. Shen
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Computational and Systems Biology Program, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - W. David Arnold
- Department of Neurology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Columbus, OH 43210, USA
- NextGen Precision Health, University of Missouri, Columbia, MO 65212, USA
| | - Dan Wang
- Horae Gene Therapy Center, University of Massachusetts, Medical School, Worcester, MA 01605, USA
- Horae Gene Therapy Center and RNA Therapeutics Institute, University of Massachusetts, Medical School, Worcester, MA 01605, USA
| | - Jun Xie
- Horae Gene Therapy Center, University of Massachusetts, Medical School, Worcester, MA 01605, USA
| | - Guangping Gao
- Horae Gene Therapy Center, University of Massachusetts, Medical School, Worcester, MA 01605, USA
- Microbiology and Physiological Systems, University of Massachusetts, Medical School, Worcester, MA 01605, USA
| | - Arthur H. M. Burghes
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Columbus, OH 43210, USA
| | - David R. Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
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Jiao Q, Liu B, Xu X, Huang T, Cao B, Wang L, Wang Q, Du A, Li J, Zhou B, Wang T. Biodegradable porous polymeric drug as a drug delivery system: alleviation of doxorubicin-induced cardiotoxicity via passive targeted release. RSC Adv 2023; 13:5444-5456. [PMID: 36793291 PMCID: PMC9923820 DOI: 10.1039/d2ra07410a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 11/22/2022] [Accepted: 02/04/2023] [Indexed: 02/15/2023] Open
Abstract
Doxorubicin (DOX) is an effective chemotherapeutic drug developed against a broad range of cancers, and its clinical applications are greatly restricted by the side effects of severe cardiotoxicity during tumour treatment. Herein, the DOX-loaded biodegradable porous polymeric drug, namely, Fc-Ma-DOX, which was stable in the circulation, but easy to compose in the acidic medium, was used as the drug delivery system avoiding the indiscriminate release of DOX. Fc-Ma was constructed via the copolymerization of 1,1'-ferrocenecarbaldehyde with d-mannitol (Ma) through the pH-sensitive acetal bonds. Echocardiography, biochemical parameters, pathological examination, and western blot results showed that DOX treatment caused increased myocardial injury and oxidative stress damage. In contrast, treatment with Fc-Ma-DOX significantly reduced myocardial injury and oxidative stress by DOX treatment. Notably, in the Fc-Ma-DOX treatment group, we observed a significant decrease in the uptake of DOX by H9C2 cells and a significant decrease in reactive oxygen species (ROS) production.
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Affiliation(s)
- Qiuhong Jiao
- Department of Cardiology, Affiliated Hospital of Weifang Medical University Weifang 261031 Shandong China
| | - Baoting Liu
- Department of Cardiology, Affiliated Hospital of Weifang Medical University Weifang 261031 Shandong China
| | - Xiufeng Xu
- Department of Geriatrics, Affiliated Hospital of Weifang Medical UniversityWeifang 261031ShandongChina
| | - Tao Huang
- Department of Cardiology, Affiliated Hospital of Weifang Medical University Weifang 261031 Shandong China
| | - Bufan Cao
- Department of Cardiology, Affiliated Hospital of Weifang Medical University Weifang 261031 Shandong China
| | - Lide Wang
- Department of Cardiology, Affiliated Hospital of Weifang Medical University Weifang 261031 Shandong China
| | - Qingguo Wang
- Department of Cardiology, Affiliated Hospital of Weifang Medical University Weifang 261031 Shandong China
| | - Ailing Du
- Department of Cardiology, Affiliated Hospital of Weifang Medical University Weifang 261031 Shandong China
| | - Jingtian Li
- Department of Cardiology, Affiliated Hospital of Weifang Medical University Weifang 261031 Shandong China
| | - Baolong Zhou
- School of Pharmacy, Weifang Medical University Weifang 261031 Shandong China
| | - Tao Wang
- Department of Cardiology, Affiliated Hospital of Weifang Medical University Weifang 261031 Shandong China
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6
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Du A, Wu X, Chen H, Bai QR, Han X, Liu B, Zhang X, Ding Z, Shen Q, Zhao C. Foxg1 Directly Represses Dbx1 to Confine the POA and Subsequently Regulate Ventral Telencephalic Patterning. Cereb Cortex 2020; 29:4968-4981. [PMID: 30843579 DOI: 10.1093/cercor/bhz037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 02/01/2019] [Accepted: 02/11/2019] [Indexed: 12/17/2022] Open
Abstract
During early development, signaling centers, such as the cortical hem and the preoptic area (POA), are critical for telencephalic patterning. However, the mechanisms underlying the maintenance of signal centers are poorly understood. Here, we report that the transcription factor Foxg1 is required to confine the POA, a resource of Sonic Hedgehog (Shh) that is pivotal for ventral telencephalic development. Cell-specific deletion of Foxg1 achieved by crossing Foxg1fl/fl with Dbx1-cre or Nestin-CreER combined with tamoxifen induction results in a dramatic expansion of the POA accompanied by the significantly increased activity of the Shh signaling pathway. Ventral pattern formation was severely impaired. Moreover, we demonstrated that Foxg1 directly represses Dbx1 to restrict the POA. Furthermore, we found that the ventral pallium was expanded, which might also contribute to the observed patterning defects. These findings will improve our understanding of the maintenance of signal centers and help to elucidate the mechanisms underlying ventral telencephalic patterning.
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Affiliation(s)
- Ailing Du
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of histology and embryology, School of Medicine, Southeast University, Nanjing 210009, China
| | - Xiaojing Wu
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of histology and embryology, School of Medicine, Southeast University, Nanjing 210009, China
| | - Hanhan Chen
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of histology and embryology, School of Medicine, Southeast University, Nanjing 210009, China
| | - Qing-Ran Bai
- Tongji Hospital, Brain and Spinal Cord Innovative Research Center, School of Life Sciences and Technology, Tongji University, Shanghai 200065, China
| | - Xiao Han
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of histology and embryology, School of Medicine, Southeast University, Nanjing 210009, China
| | - Bin Liu
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of histology and embryology, School of Medicine, Southeast University, Nanjing 210009, China
| | - Xiaohu Zhang
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of histology and embryology, School of Medicine, Southeast University, Nanjing 210009, China
| | - Zhaoying Ding
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of histology and embryology, School of Medicine, Southeast University, Nanjing 210009, China
| | - Qin Shen
- Tongji Hospital, Brain and Spinal Cord Innovative Research Center, School of Life Sciences and Technology, Tongji University, Shanghai 200065, China
| | - Chunjie Zhao
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of histology and embryology, School of Medicine, Southeast University, Nanjing 210009, China
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Surmanowicz P, Sivanand A, Du A, Gniadecki R. 913 A variant of Mohs micrographic surgery: The muffin technique. J Invest Dermatol 2020. [DOI: 10.1016/j.jid.2020.03.929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Sinclair D, Featherstone R, Naschek M, Nam J, Du A, Wright S, Pance K, Melnychenko O, Weger R, Akuzawa S, Matsumoto M, Siegel SJ. GABA-B Agonist Baclofen Normalizes Auditory-Evoked Neural Oscillations and Behavioral Deficits in the Fmr1 Knockout Mouse Model of Fragile X Syndrome. eNeuro 2017; 4:ENEURO.0380-16.2017. [PMID: 28451631 PMCID: PMC5394929 DOI: 10.1523/eneuro.0380-16.2017] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/09/2017] [Accepted: 02/13/2017] [Indexed: 12/15/2022] Open
Abstract
Fragile X syndrome is a genetic condition resulting from FMR1 gene mutation that leads to intellectual disability, autism-like symptoms, and sensory hypersensitivity. Arbaclofen, a GABA-B agonist, has shown efficacy in some individuals with FXS but has become unavailable after unsuccessful clinical trials, prompting interest in publicly available, racemic baclofen. The present study investigated whether racemic baclofen can remediate abnormalities of neural circuit function, sensory processing, and behavior in Fmr1 knockout mice, a rodent model of fragile X syndrome. Fmr1 knockout mice showed increased baseline and auditory-evoked high-frequency gamma (30-80 Hz) power relative to C57BL/6 controls, as measured by electroencephalography. These deficits were accompanied by decreased T maze spontaneous alternation, decreased social interactions, and increased open field center time, suggestive of diminished working memory, sociability, and anxiety-like behavior, respectively. Abnormal auditory-evoked gamma oscillations, working memory, and anxiety-related behavior were normalized by treatment with baclofen, but impaired sociability was not. Improvements in working memory were evident predominantly in mice whose auditory-evoked gamma oscillations were dampened by baclofen. These findings suggest that racemic baclofen may be useful for targeting sensory and cognitive disturbances in fragile X syndrome.
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Affiliation(s)
- D Sinclair
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - R Featherstone
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - M Naschek
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - J Nam
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - A Du
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - S Wright
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - K Pance
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - O Melnychenko
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - R Weger
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - S Akuzawa
- Neuroscience Research Unit, DDR, Astellas Pharma Inc., Tsukuba-Shi, Ibaraki 305-8585, Japan
| | - M Matsumoto
- Neuroscience Research Unit, DDR, Astellas Pharma Inc., Tsukuba-Shi, Ibaraki 305-8585, Japan
| | - S J Siegel
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
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9
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Lan L, Zuo B, Ding H, Huang Y, Chen X, Du A. Anticoccidial evaluation of a traditional chinese medicine—Brucea javanica—in broilers. Poult Sci 2016; 95:811-8. [DOI: 10.3382/ps/pev441] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 11/08/2015] [Indexed: 01/04/2023] Open
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10
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Wang J, Yang Y, Guo S, Chen Y, Yang C, Ji H, Song X, Zhang F, Jiang Z, Ma Y, Li Y, Du A, Jin L, Reveille JD, Zou H, Zhou X. Association between copy number variations of HLA-DQA1 and ankylosing spondylitis in the Chinese Han population. Genes Immun 2013; 14:500-3. [PMID: 24048351 PMCID: PMC3855587 DOI: 10.1038/gene.2013.46] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [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: 05/06/2013] [Revised: 08/02/2013] [Accepted: 08/05/2013] [Indexed: 11/20/2022]
Abstract
Ankylosing spondylitis (AS) is a chronic inflammatory disease with complex genetic traits. Multiple sequence variations have been associated with AS, but explained only a proportion of heritability. The studies herein aimed to explore potential associations between genomic copy number variation (CNV) and AS of Han Chinese. Five AS patients were examined with the high-density comparative genomic hybridization (CGH) microarrays in the first screen test for AS associated CNVs. A total of 533 AS patients and 792 unrelated controls were examined in confirmation studies with the AccuCopy assays. A significant association was observed between the CNV of the HLA-DQA1 and AS. Comparing with controls, AS patients showed an aberrant copy number (CN), and significantly increased number of patients had more than 2 copies of the HLA-DQA1. Therefore, CNV of the HLA-DQA1 may play an important role in susceptibility to AS in Han Chinese population.
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Affiliation(s)
- J Wang
- 1] State Key Laboratory of Genetic Engineering and Ministry of Education (MOE), Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China [2] Institute of Rheumatology, Immunology and Allergy, Fudan University, Shanghai, China
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11
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Du A, Zhang Z, Wu M. The effect of pyrolytic carbon black prepared from junked tires on the properties of ethylene-propylene-diene copolymers (EPDM). EXPRESS POLYM LETT 2009. [DOI: 10.3144/expresspolymlett.2009.37] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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12
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Guo X, Du A, Guan C, Pan G, Du A, Wang W. [Analysis of volatile oil of garlic by gas chromatography-mass spectrometry]. Se Pu 2005; 23:548-50. [PMID: 16350805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023] Open
Abstract
The volatile oil of garlic was extracted by hydrodistillation method and gas chromatography-mass spectrometry was applied to analyse the compounds in the oil. The best extraction conditions for high-content, effective components were obtained through optimization. The capillary column was an HP-5MS column (25 mm x 0.25 mm i.d. x 0.25 microm); oven temperature increased with a rate of 5 degrees C /min from 80 to 300 degrees C, and then maintained for 20 min; sample size of 1 microL; split ratio of 100:1; carrier gas of helium (1 mL/min). Mass spectra were obtained at 70 eV. The temperatures of injector base, ionization source were maintained at 270 degrees C, 230 degrees C respectively. Under these conditions, twenty compounds in the volatile oil of garlic were isolated and identified, and the content of each was determined. Sulfur-containing compounds were found to be the principal components, of which the major compound was diallyl trisulfide with the content of more than 30%, which is higher than the others in the literature. The experimental results also indicated that hydrodistillation method is an effective method for officinal component extraction. In addition, it was also demonstrated that the garlic volatile oil was stable when stored at 0 degrees C for 6 months.
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Affiliation(s)
- Xiaofei Guo
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250061, China.
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13
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Abstract
A liquid and a powder made from a herbal complex consisting of Uncariae Ramulus cum Uncis, Agrimoniae Herba, Sanguisorbae Radix, Eclipta Prostrate Herba, Pulsatillae Radix, Sophorae Flavescentis Radix, Rehmanniae Radix and Glycyrrhizae Radix were studied for their anticoccidial activities in chickens. Chickens were administered with herbal liquid, powder, diclazuril or without medication during the study and challenged with oocysts of Eimeria tenella. Results indicated that the birds medicated showed less bloody faeces than those without medication. The intestinal lesion was mild in the chicks medicated with herbal liquid without significantly different lesion score when compared with uninfected chicks. The birds with medication had significantly higher body weight gains than birds without medication. Therefore, the herbal complex used in this study was effective against E. tenella infection in chickens.
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Affiliation(s)
- A Du
- Department of Veterinary Medicine, College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang 310029, China.
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14
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Qu W, Du A, Zhao D. Determination of (187)Os in molybdenite by ICP-MS with neutron-induced (186)Os and (188)Os spikes. Talanta 2001; 55:815-20. [PMID: 18968429 DOI: 10.1016/s0039-9140(01)00506-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2000] [Revised: 07/02/2001] [Accepted: 07/03/2001] [Indexed: 10/18/2022]
Abstract
The article describes a method for the determination of (187)Os in molybdenite by isotope dilution inductively coupled plasma-mass spectrometry (ID-ICP-MS) with neutron-induced (186)Os and (188)Os spike. The spike used in the present work was prepared in line with the principle by which artificial nuclides are produced in a nuclear reaction. The concentration and isotopic composition of osmium in the prepared spike were evaluated accurately with the isotope dilution method, using negative thermal ion mass spectrometry (N-TIMS). The advantage of this method is that using (186)Os and (188)Os double spikes can effectively compensate for the mass discrimination effects of ICP-MS. Thus, the common correction practice for mass bias in the isotope dilution method with a single spike is unnecessary. In addition, the method enables one to reduce the determined error arising from instrumental instability. The precision for the (187)Os/((186)Os+(188)Os) ratio was approximately 2% (2sigma, RSD), but in the case of (187)Os/(186)Os, (187)Os/(188)Os and (186)Os/(188)Os, precision ranged from 2.0 to 8% (2sigma, RSD). The results for (187)Os concentration in a molybdenite sample determined with this method showed good agreement with reference values.
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Affiliation(s)
- W Qu
- National Research Center of Geoanalysis, 26 Baiwanzhuang Road, Beijing 100037, People's Republic of China; Central Iron and Steel Research Institute, 76 Xueyuan Nanlu, Beijing 100081, People's Republic of China
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15
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Mutlib AE, Shockcor J, Espina R, Graciani N, Du A, Gan LS. Disposition of glutathione conjugates in rats by a novel glutamic acid pathway: characterization of unique peptide conjugates by liquid chromatography/mass spectrometry and liquid chromatography/NMR. J Pharmacol Exp Ther 2000; 294:735-45. [PMID: 10900255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
With the advent of liquid chromatography/mass spectrometry and liquid chromatography/NMR, it has become easier to characterize metabolites that were once difficult to isolate and identify. These techniques have enabled us to uncover the existence of an alternate pathway for the disposition of glutathione adducts of several structurally diverse compounds. Studies were carried out using acetaminophen as a model compound to investigate the role of the glutamic acid pathway in disposition of the glutathione adducts. Although the mercapturic acid pathway was the major route of degradation of the glutathione adducts, it was found that the conjugation of the glutathione, cysteinylglycine, and cysteine adducts of acetaminophen with the gamma-carboxylic acid of the glutamic acid was both interesting and novel. The coupling of the glutathione adduct and the products from the mercapturic acid pathway with the glutamic acid led to unusual peptide conjugates. The natures of these adducts were confirmed unequivocally by comparisons with synthetic standards. This pathway (addition of glutamic acids) led to larger peptides, in contrast to the mercapturic acid pathway, in which the glutathione adducts are broken down to smaller molecules. The enzyme responsible for the addition of glutamic acid to the different elements of the mercapturic acid pathway is currently unknown. It is postulated that the gamma-carboxylic acid is activated (perhaps by ATP) before enzymatic addition to the alpha-amino group of cysteine or glutamate takes place. The discovery of these peptide conjugates of acetaminophen represents a novel disposition of glutathione adducts of compounds. The formation of such conjugates may represent yet another pathway by which drugs could produce covalent binding via their reactive intermediates.
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Affiliation(s)
- A E Mutlib
- Drug Metabolism and Pharmacokinetics Section, DuPont Pharmaceuticals Company, Stine-Haskell Research Center, Newark, DE 19714-0030, USA.
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Mutlib A, Chen H, Shockcor J, Espina R, Chen S, Cao K, Du A, Nemeth G, Prakash S, Gan LS. Characterization of novel glutathione adducts of a non-nucleoside reverse transcriptase inhibitor, (S)-6-chloro-4-(cyclopropylethynyl)-4-(trifluoromethyl)-3, 4-dihydro-2(1H)-quinazolinone (DPC 961), in rats. Possible formation of an oxirene metabolic intermediate from a disubstituted alkyne. Chem Res Toxicol 2000; 13:775-84. [PMID: 10956066 DOI: 10.1021/tx000029g] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [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: 11/29/2022]
Abstract
The postulated formation of oxirene-derived metabolites from rats treated with a disubstituted alkyne, (S)-6-chloro-4-(cyclopropylethynyl)-4-(trifluoromethyl)-3, 4-dihydro-2(1H)-quinazolinone (DPC 961), is described. The reactivity of this postulated oxirene intermediate led to the formation of novel glutathione adducts whose structures were confirmed by LC/MS and by two-dimensional NMR experiments. These metabolites were either excreted in rat bile or degraded to mercapturic acid conjugates and eliminated in urine. To demonstrate the oxidation of the triple bond, an analogue of DPC 961 was synthesized, whereby the two carbons of the alkyne moiety were replaced with (13)C stable isotope labels. Rats were orally administered [(13)C]DPC 961 and glutathione adducts isolated from bile. The presence of an oxygen atom on one of the (13)C labels of the alkyne was demonstrated unequivocally by NMR experiments. Administration of (14)C-labeled DPC 961 showed that biliary elimination was the major route of excretion with the 8-OH glucuronide conjugate (M1) accounting for greater than 90% of the eliminated radioactivity. On the basis of radiochemical profiling, the glutathione-derived metabolites were minor in comparison to the glucuronide conjugate. Studies with cDNA-expressed rat enzymes, polyclonal antibodies, and chemical inhibitors pointed to the involvement of P450 3A1 and P450 1A2 in the formation of the postulated oxirene intermediate. The proposed mechanism shown in Scheme 1 begins with P450-catalyzed formation of an oxirene, rearrangement to a reactive cyclobutenyl ketone, and a 1,4-Michael addition with endogenous glutathione to produce two isomeric adducts, GS-1 and GS-2. The glutathione adducts were subsequently catabolized via the mercapturic acid pathway to cysteinylglycine, cysteine, and N-acetylcysteine adducts. The transient existence of the alpha,beta-unsaturated cyclobutenyl ketone was demonstrated by incubating the glutathione adduct in the presence of N-acetylcysteine and monitoring the formation of N-acetylcysteine adducts by LC/MS. Epimerization of GS-1 to GS-2 was also observed when N-acetylcysteine was omitted from the incubation.
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Affiliation(s)
- A Mutlib
- Drug Metabolism and Pharmacokinetics Section and Department of Chemical and Physical Sciences, DuPont Pharmaceuticals Company, Stine-Haskell Research Center, P.O. Box 30, Newark, Delaware 19714, USA.
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17
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Du A, Zou W. [The role of bFGF in renal tubular injury and the interstitial lesion]. Zhonghua Bing Li Xue Za Zhi 2000; 29:208-11. [PMID: 11866915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE The role of bFGF in renal tubular injury, regeneration and interstitial lesion of rats was studied. METHODS The renal tubular injury model of rat was induced by intraperitoneal injection of gentamicin. The expression of bFGF and FGFR1 was examined by Northern blot, in situ hybridization and immunohistochemistry. (3)H-TdR incorporation was used to detect the role of bFGF in promoting the proliferation of renal tubular epithelial cells and renal fibroblasts. RESULTS The expression of bFGF mRNA and protein synthesis of bFGF and FGFR1 increased during the process of injury and regeneration of tubular epithelial cells. In contrast, normal tubular epithelium failed to express bFGF, except renal interstitial fibroblasts and monocytes/macrophages. bFGF promoted proliferation of renal tubular epithelium as well as renal interstitial fibroblasts. CONCLUSION bFGF is secreted by tubular epithelial cells damaged by nephrotoxicity of gentamicin, and FGFR1 expressed in damaged renal tubules and interstitial fibroblasts. bFGF not only can promote tubular epithelia to proliferate, but can also stimulate interstitial fibroblasts to proliferate. Correlation exists between bFGF, renal tubular injury and interstitial lesions.
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Affiliation(s)
- A Du
- Department of Pathology, Beijing Medical University, Beijing 100083, China
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18
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Abstract
BACKGROUND Myosin II, a conventional myosin, is dispensable for mitotic division in Dictyostelium if the cells are attached to a substrate, but is required when the cells are growing in suspension. Only a small fraction of myosin II-null cells fail to divide when attached to a substrate. Cortexillins are actin-bundling proteins that translocate to the midzone of mitotic cells and are important for the formation of a cleavage furrow, even in attached cells. Here, we investigated how myosin II and cortexillin I cooperate to determine the position of a cleavage furrow. RESULTS Using a green fluorescent protein (GFP)-cortexillin I fusion protein as a marker for priming of a cleavage furrow, we found that positioning of a cleavage furrow occurred in two steps. In the first step, which was independent of myosin II and substrate, cortexillin I delineated a zone around the equatorial region of the cell. Myosin II then focused the cleavage furrow to the middle of this cortexillin I zone. If asymmetric cleavage in the absence of myosin II partitioned a cell into a binucleate and an anucleate portion, cell-surface ruffles were induced along the cleavage furrow, which led to movement of the anucleate portion along the connecting strand towards the binucleate one. CONCLUSIONS In myosin II-null cells, cleavage furrow positioning occurs in two steps: priming of the furrow region and actual cleavage, which may proceed in the middle or at one border of the cortexillin ring. A control mechanism acting at late cytokinesis prevents cell division into an anucleate and a binucleate portion, causing a displaced furrow to regress if it becomes aberrantly located on top of polar microtubule asters.
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Affiliation(s)
- I Weber
- Max-Planck-Institut für Biochemie, Martinsried, D-82152, Germany
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19
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Li G, Huang M, Yang G, Wu G, Du A, Su Y. [The enantiomeric separation of aromatic alcohol amino drugs by thin-layer chromatography]. Se Pu 1999; 17:215-6. [PMID: 12549175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023] Open
Abstract
Two chiral aromatic alcohol amino drugs, Labarol and Bataroc, were resolved by thinlayer chromatography (TLC) on the silica gel GF254 plates (2.5 cm x 10 cm), by using the ammonium-D-10-camphorsulfonate (CSA) as chiral ion-pair interaction agent which was added to the mobile phase in the ammonium form. All developments were carried out at lower temperature (2-4 degrees C, in a refrigerator) in small glass jars of 250 mL volume. These two drugs were not resolved at room temperature (15-30 degrees C). Analytical reagent grade methanol and dichloromethane can be directly used as mobile phase without further drying. The chiral separation occured over a range from 40% to 70% (optimum 67%) dichloromethane in the mobile phase volume ratio and 55% to 80% (optimum 60%) dichloromethane in the mobile phase volume ratio. These separation conditions were easily obtained. This method is relatively inexpensive and attractive.
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Affiliation(s)
- G Li
- Department of Chemistry, Shandong University, Jinan, 250100
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20
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Huang M, Sun J, Li G, Yang G, Du A, Gao Z, Wang J. [The preparation of chiral column of cellulose triacetate coated on small pore silica gel and the separation of enantiomers]. Se Pu 1998; 16:47-9. [PMID: 11324478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
The cellulose triacetate (CTA) prepared by heterogeneous acetylation and coated on small pore 3-aminopropyl silica gel (10 nm) was used as chiral stationary phase for HPLC (OA column). The racemes of three drugs, two fulvenes and one dazine, were separated on this column. Among these racemes, timolol maleas was separated using 1.0 mol/L NaClO4:95% ethanol = 10:90 as mobile phase. Without NaClO4 in mobile phase, the resolution of timolol maleas can not occur. Ethanols of 95%-98% were used as mobile phase for other racemes. The influence of the content of water in mobile phase on the chiral separation of praziquentelum, the retention time and separation factor (alpha) were reduced with the increase of water content in mobile phase. When the content of water in the mobile phase was 13%, praziquentelum could not be separated. It was found that in the case of samples No. 1 and No. 2, when the substituents R1 and R2 or R'1 and R'2 of fulvenes are 4-methoxybenzoyl and 4-methoxyphenyl, the chiral separations of fulvenes can be obtained. For sample No. 4 when R1 and R2 of fulvenes are 2-methylbenzoyl and 2-methylphenyl or in the case of No. 5, when R1 and R2 are 5-bromo-2-furoyl and 5-bromo-2-furan, the chiral separations of fulvenes can not be achieved. For sample No. 6 and No. 7, when R'1 are 4-chlorobenzoyl and benzoyl or R'2 are 4-chlorophenyl and phenyl, the chiral separation also can not be achieved. The column performance and separation factor were not obviously reduced after used for four months.
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Affiliation(s)
- M Huang
- Department of Chemistry, Experimental Center, Shandong University, Jinan, 250100
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Du A, Wei GZ. Low-temperature properties of quasi-one-dimensional Heisenberg ferromagnets. Phys Rev B Condens Matter 1994; 49:15360-15362. [PMID: 10010654 DOI: 10.1103/physrevb.49.15360] [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: 11/07/2022]
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Abstract
The double-time-temperature spin Green's function method is used to study the magnetic properties of layered ferromagnets with arbitrary spin S, within Tyablikov's decoupling approximation. According to the extent to which interlayer coupling suppresses twodimensional spin fluctuations, we divide the low-temperature region into two new ones, and give the asymptotic expressions for magnetisation and susceptibility over different temperature regions, including the low-temperature region, the vicinity of the Curie temperature and the high-temperature region. We also give the Curie temperature in an asymptotic form when inter layer coupling is weak.
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