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Wang H, Yang G, Zhang X, Zhang H, Liu Y, Wang C, Miao L, Li Y, Huang Y, Teng H, Wang S, Cheng H, Zeng X. Cannabidiol protects the liver from α-Amanitin-induced apoptosis and oxidative stress through the regulation of Nrf2. Food Chem Toxicol 2023; 182:114196. [PMID: 37992955 DOI: 10.1016/j.fct.2023.114196] [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] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 10/30/2023] [Accepted: 11/16/2023] [Indexed: 11/24/2023]
Abstract
α-Amanitin, the primary lethal toxin of Amanita, specifically targets the liver, causing oxidative stress, hepatocyte apoptosis, and irreversible liver damage. As little as 0.1 mg/kg of α-amanitin can be lethal for humans, and there is currently no effective antidote for α-amanitin poisoning. Cannabidiol is a non-psychoactive natural compound derived from Cannabis sativa that exhibits a wide range of anti-inflammatory, antioxidant, and anti-apoptotic effects. It may play a protective role in preventing liver damage induced by α-amanitin. To investigate the potential protective effects of cannabidiol on α-amanitin-induced hepatocyte apoptosis and oxidative stress, we established α-amanitin exposure models using C57BL/6J mice and L-02 cells in vitro. Our results showed that α-amanitin exposure led to oxidative stress, apoptosis, and DNA damage in both mouse hepatocytes and L-02 cells, resulting in the death of mice. We also found that cannabidiol upregulated the level of Nrf2 and antioxidant enzymes, alleviating apoptosis, and oxidative stress in mouse hepatocytes and L-02 cells and increasing the survival rate of mice. Our findings suggest that cannabidiol has hepatoprotective effects through the regulation of Nrf2 and antioxidant enzymes and may be a potential therapeutic drug for Amanita poisoning.
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Affiliation(s)
- Haowei Wang
- NHC Key Laboratory of Drug Addiction Medicine, Department of Forensic Medicine, School of Forensic Medicine, Kunming Medical University, Kunming, China
| | - Genmeng Yang
- NHC Key Laboratory of Drug Addiction Medicine, Department of Forensic Medicine, School of Forensic Medicine, Kunming Medical University, Kunming, China
| | - Xiaoxing Zhang
- NHC Key Laboratory of Drug Addiction Medicine, Department of Forensic Medicine, School of Forensic Medicine, Kunming Medical University, Kunming, China
| | - Huijie Zhang
- NHC Key Laboratory of Drug Addiction Medicine, Department of Forensic Medicine, School of Forensic Medicine, Kunming Medical University, Kunming, China
| | - Yan Liu
- NHC Key Laboratory of Drug Addiction Medicine, Department of Forensic Medicine, School of Forensic Medicine, Kunming Medical University, Kunming, China
| | - Chan Wang
- NHC Key Laboratory of Drug Addiction Medicine, Department of Forensic Medicine, School of Forensic Medicine, Kunming Medical University, Kunming, China
| | - Lin Miao
- NHC Key Laboratory of Drug Addiction Medicine, Department of Forensic Medicine, School of Forensic Medicine, Kunming Medical University, Kunming, China
| | - Yi Li
- NHC Key Laboratory of Drug Addiction Medicine, Department of Forensic Medicine, School of Forensic Medicine, Kunming Medical University, Kunming, China
| | - Yizhen Huang
- NHC Key Laboratory of Drug Addiction Medicine, Department of Forensic Medicine, School of Forensic Medicine, Kunming Medical University, Kunming, China
| | - Hanxin Teng
- Department of Pathogen Biology and Immunology, School of Basic Medical Science, Kunming Medical University, Kunming, China
| | - Shangwen Wang
- NHC Key Laboratory of Drug Addiction Medicine, Department of Forensic Medicine, School of Forensic Medicine, Kunming Medical University, Kunming, China.
| | - Hao Cheng
- NHC Key Laboratory of Drug Addiction Medicine, Department of Forensic Medicine, School of Forensic Medicine, Kunming Medical University, Kunming, China.
| | - Xiaofeng Zeng
- NHC Key Laboratory of Drug Addiction Medicine, Department of Forensic Medicine, School of Forensic Medicine, Kunming Medical University, Kunming, China.
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Rasooly R, Do P, He X, Hernlem B. A Sensitive, Cell-Based Assay for Measuring Low-Level Biological Activity of α-Amanitin. Int J Mol Sci 2023; 24:16402. [PMID: 38003593 PMCID: PMC10671307 DOI: 10.3390/ijms242216402] [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] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/10/2023] [Accepted: 11/14/2023] [Indexed: 11/26/2023] Open
Abstract
α-Amanitin is one of the primary toxins produced by the poisonous mushroom genus, Amanita. Because it is odorless and tasteless, it is an important cause of death from the consumption of misidentified mushrooms. To study the thermal stability of α-amanitin, novel cell-based assays were developed to measure the toxin's activity, based on the inhibition of RNA polymerase II by α-amanitin. First, an MTT-formazan cell viability assay was used to measure the biological activity of α-amanitin through the inhibition of cellular activity. This method can detect 10 μg/mL of α-amanitin in a time-dependent manner. Second, a more sensitive quantitative PCR approach was developed to examine its inhibition of viral replication. The new RT-qPCR assay enabled the detection of 100 ng/mL. At this level, α-amanitin still significantly reduced adenovirus transcription. Third, a simpler GFP expression-based assay was developed with an equal sensitivity to the RT-qPCR assay. With this assay, aqueous α-amanitin heated at 90 °C for 16 h or treated in the microwave for 3 min retained its biological activity when tested in HEK293 cells, but a slight reduction was observed when tested in Vero cells. Beyond detecting the activity of α-amanitin, the new method has a potential application for detecting the activity of other toxins that are RNA polymerase inhibitors.
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Affiliation(s)
- Reuven Rasooly
- Foodborne Toxin Detection & Prevention Research Unit, Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, CA 94710, USA; (P.D.); (X.H.); (B.H.)
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Viegas JO, Fishman L, Meshorer E, Rabani M. Calculating RNA degradation rates using large-scale normalization in mouse embryonic stem cells. STAR Protoc 2023; 4:102534. [PMID: 37656628 PMCID: PMC10495639 DOI: 10.1016/j.xpro.2023.102534] [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] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/29/2023] [Accepted: 08/02/2023] [Indexed: 09/03/2023] Open
Abstract
Data normalization is critical to the process of estimating RNA degradation by analyzing RNA levels when transcription is blocked. Here, we present a protocol for measuring mRNA degradation rates, optimized for mouse embryonic stem cells, using α-amanitin inhibitor. We describe steps for a time course α-amanitin treatment, RNA-seq, and alignment; we then detail procedures for analyzing data and sequence enrichment. Our method relies on large-scale normalization of stable transcripts in genomic RNA-seq measurements, providing reliable readouts. For complete details on the use and execution of this protocol, please refer to Viegas et al.1.
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Affiliation(s)
- Juliane Oliveira Viegas
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel
| | - Lior Fishman
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel
| | - Eran Meshorer
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel.
| | - Michal Rabani
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel.
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Ríos-Meléndez S, Valadez-Hernández E, Delgadillo C, Luna-Guevara ML, Martínez-Núñez MA, Sánchez-Pérez M, Martínez-Y-Pérez JL, Arroyo-Becerra A, Cárdenas L, Bibbins-Martínez M, Maldonado-Mendoza IE, Villalobos-López MA. Pseudocrossidium replicatum (Taylor) R.H. Zander is a fully desiccation-tolerant moss that expresses an inducible molecular mechanism in response to severe abiotic stress. Plant Mol Biol 2021; 107:387-404. [PMID: 34189708 PMCID: PMC8648698 DOI: 10.1007/s11103-021-01167-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 06/10/2021] [Indexed: 05/04/2023]
Abstract
KEY MESSAGE The moss Pseudocrossidium replicatum is a desiccation-tolerant species that uses an inducible system to withstand severe abiotic stress in both protonemal and gametophore tissues. Desiccation tolerance (DT) is the ability of cells to recover from an air-dried state. Here, the moss Pseudocrossidium replicatum was identified as a fully desiccation-tolerant (FDT) species. Its gametophores rapidly lost more than 90% of their water content when exposed to a low-humidity atmosphere [23% relative humidity (RH)], but abscisic acid (ABA) pretreatment diminished the final water loss after equilibrium was reached. P. replicatum gametophores maintained good maximum photosystem II (PSII) efficiency (Fv/Fm) for up to two hours during slow dehydration; however, ABA pretreatment induced a faster decrease in the Fv/Fm. ABA also induced a faster recovery of the Fv/Fm after rehydration. Protein synthesis inhibitor treatment before dehydration hampered the recovery of the Fv/Fm when the gametophores were rehydrated after desiccation, suggesting the presence of an inducible protective mechanism that is activated in response to abiotic stress. This observation was also supported by accumulation of soluble sugars in gametophores exposed to ABA or NaCl. Exogenous ABA treatment delayed the germination of P. replicatum spores and induced morphological changes in protonemal cells that resembled brachycytes. Transcriptome analyses revealed the presence of an inducible molecular mechanism in P. replicatum protonemata that was activated in response to dehydration. This study is the first RNA-Seq study of the protonemal tissues of an FDT moss. Our results suggest that P. replicatum is an FDT moss equipped with an inducible molecular response that prepares this species for severe abiotic stress and that ABA plays an important role in this response.
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Affiliation(s)
- Selma Ríos-Meléndez
- Laboratorio de Genómica Funcional y Biotecnología de Plantas, Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional, C.P. 90700, Tepetitla de Lardizábal, Tlaxcala, México
| | - Emmanuel Valadez-Hernández
- Laboratorio de Genómica Funcional y Biotecnología de Plantas, Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional, C.P. 90700, Tepetitla de Lardizábal, Tlaxcala, México
| | - Claudio Delgadillo
- Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Maria L Luna-Guevara
- Facultad de Ingeniería Química, Benemérita Universidad Autónoma de Puebla, C.P. 72000, Puebla, Puebla, México
| | - Mario A Martínez-Núñez
- UMDI-Sisal, Facultad de Ciencias, Universidad Nacional Autónoma de México, C.P. 97302, Mérida, Yucatán, México
| | - Mishael Sánchez-Pérez
- Unidad de Análisis Bioinformáticos, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, C.P. 62210, Cuernavaca, Morelos, México
| | - José L Martínez-Y-Pérez
- Centro de Investigación en Genética y Ambiente, Universidad Autónoma de Tlaxcala, C.P. 90210, Ixtacuixtla, Tlaxcala, México
| | - Analilia Arroyo-Becerra
- Laboratorio de Genómica Funcional y Biotecnología de Plantas, Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional, C.P. 90700, Tepetitla de Lardizábal, Tlaxcala, México
| | - Luis Cárdenas
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, C.P. 62210, Cuernavaca, Morelos, México
| | - Martha Bibbins-Martínez
- Laboratorio de Genómica Funcional y Biotecnología de Plantas, Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional, C.P. 90700, Tepetitla de Lardizábal, Tlaxcala, México
| | - Ignacio E Maldonado-Mendoza
- Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional, Unidad Sinaloa, Instituto Politécnico Nacional, C.P. 81049, Guasave, Sinaloa, México
| | - Miguel Angel Villalobos-López
- Laboratorio de Genómica Funcional y Biotecnología de Plantas, Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional, C.P. 90700, Tepetitla de Lardizábal, Tlaxcala, México.
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TANABE T, FUKUDA Y, KAWASHIMA K, YAMAMOTO S, KASHIMOTO T, SATO H. Transcriptional inhibition of feline immunodeficiency virus by alpha-amanitin. J Vet Med Sci 2021; 83:158-161. [PMID: 33250482 PMCID: PMC7870409 DOI: 10.1292/jvms.20-0182] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 11/15/2020] [Indexed: 11/22/2022] Open
Abstract
Alpha-amanitin, one of the amatoxins in egg amanita, has a cyclic peptide structure, and was reported as having antiviral activity against several viruses. We investigated whether α-amanitin has antiviral activity against feline immunodeficiency virus (FIV). FL-4 cells persistently infected with FIV Petaluma were cultured with α-amanitin. Reverse transcriptase (RT) activity in the supernatant of FL-4 cells was significantly inhibited by α-amanitin. In addition, the production of FIV core protein in FL-4 cells was inhibited by α-amanitin when analyzed by western blotting. Furthermore, α-amanitin inhibited the transcription of FIV in real-time RT-PCR. These data suggested that α-amanitin showed anti-FIV activity by inhibiting the RNA transcription level.
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Affiliation(s)
- Taishi TANABE
- Laboratory of Veterinary Microbiology, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628, Japan
| | - Yurina FUKUDA
- Laboratory of Veterinary Microbiology, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628, Japan
| | | | - Satomi YAMAMOTO
- Laboratory of Veterinary Microbiology, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628, Japan
| | - Takashige KASHIMOTO
- Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628, Japan
| | - Hisaaki SATO
- Laboratory of Veterinary Microbiology, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628, Japan
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Van der Jeught K, Xu HC, Li YJ, Lu XB, Ji G. Drug resistance and new therapies in colorectal cancer. World J Gastroenterol 2018; 24:3834-3848. [PMID: 30228778 PMCID: PMC6141340 DOI: 10.3748/wjg.v24.i34.3834] [Citation(s) in RCA: 343] [Impact Index Per Article: 57.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 06/25/2018] [Accepted: 07/16/2018] [Indexed: 02/06/2023] Open
Abstract
Colorectal cancer (CRC) is often diagnosed at an advanced stage when tumor cell dissemination has taken place. Chemo- and targeted therapies provide only a limited increase of overall survival for these patients. The major reason for clinical outcome finds its origin in therapy resistance. Escape mechanisms to both chemo- and targeted therapy remain the main culprits. Here, we evaluate major resistant mechanisms and elaborate on potential new therapies. Amongst promising therapies is α-amanitin antibody-drug conjugate targeting hemizygous p53 loss. It becomes clear that a dynamic interaction with the tumor microenvironment exists and that this dictates therapeutic outcome. In addition, CRC displays a limited response to checkpoint inhibitors, as only a minority of patients with microsatellite instable high tumors is susceptible. In this review, we highlight new developments with clinical potentials to augment responses to checkpoint inhibitors.
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Affiliation(s)
- Kevin Van der Jeught
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Han-Chen Xu
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Yu-Jing Li
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Xiong-Bin Lu
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, United States
- Indiana University Melvin and Bren Simon Cancer Center, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Guang Ji
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
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Świderska KW, Szlachcic A, Opaliński Ł, Zakrzewska M, Otlewski J. FGF2 Dual Warhead Conjugate with Monomethyl Auristatin E and α-Amanitin Displays a Cytotoxic Effect towards Cancer Cells Overproducing FGF Receptor 1. Int J Mol Sci 2018; 19:ijms19072098. [PMID: 30029518 PMCID: PMC6073801 DOI: 10.3390/ijms19072098] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [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: 06/06/2018] [Revised: 07/12/2018] [Accepted: 07/18/2018] [Indexed: 02/03/2023] Open
Abstract
In the rapidly developing field of targeted cancer therapy there is growing interest towards therapeutics combining two or more compounds to achieve synergistic action and minimize the chance of cancer resistance to treatment. We developed a fibroblast growth factor 2 (FGF2)-conjugate bearing two cytotoxic drugs with independent mode of action: α-amanitin and monomethyl auristatin E. Drugs are covalently attached to the targeting protein in a site-specific manner via maleimide-thiol conjugation and Cu(I)-catalyzed alkyne-azide cycloaddition. The dual warhead conjugate binds to FGF receptor 1 (FGFR1) and utilizes receptor-mediated endocytosis for selective internalization into cancer cells with FGFR1. The developed conjugate displays high cytotoxicity towards all tested FGFR1-positive cell lines. Most importantly, the improved cytotoxic effect of both drugs is observed for lung cancer cell line NCI-H446. The single drug-FGF2 conjugates have no impact on the viability of NCI-H446 cells, whereas the dual warhead-FGF2 conjugate selectively and efficiently kills these FGFR1 positive cancer cells. Due to the diversified mode of action the dual warhead-FGF2 conjugate may overcome the potential acquired resistance of FGFR1-overproducing cancer cells towards single cytotoxic drugs.
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Affiliation(s)
- Karolina Weronika Świderska
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383 Wroclaw, Poland.
| | - Anna Szlachcic
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383 Wroclaw, Poland.
| | - Łukasz Opaliński
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383 Wroclaw, Poland.
| | - Małgorzata Zakrzewska
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383 Wroclaw, Poland.
| | - Jacek Otlewski
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383 Wroclaw, Poland.
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Radiske A, Gonzalez MC, Conde-Ocazionez SA, Feitosa A, Köhler CA, Bevilaqua LR, Cammarota M. Prior Learning of Relevant Nonaversive Information Is a Boundary Condition for Avoidance Memory Reconsolidation in the Rat Hippocampus. J Neurosci 2017; 37:9675-9685. [PMID: 28887385 PMCID: PMC6596618 DOI: 10.1523/jneurosci.1372-17.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 08/13/2017] [Accepted: 08/28/2017] [Indexed: 01/07/2023] Open
Abstract
Reactivated memories can be modified during reconsolidation, making this process a potential therapeutic target for posttraumatic stress disorder (PTSD), a mental illness characterized by the recurring avoidance of situations that evoke trauma-related fears. However, avoidance memory reconsolidation depends on a set of still loosely defined boundary conditions, limiting the translational value of basic research. In particular, the involvement of the hippocampus in fear-motivated avoidance memory reconsolidation remains controversial. Combining behavioral and electrophysiological analyses in male Wistar rats, we found that previous learning of relevant nonaversive information is essential to elicit the participation of the hippocampus in avoidance memory reconsolidation, which is associated with an increase in theta- and gamma-oscillation power and cross-frequency coupling in dorsal CA1 during reactivation of the avoidance response. Our results indicate that the hippocampus is involved in memory reconsolidation only when reactivation results in contradictory representations regarding the consequences of avoidance and suggest that robust nesting of hippocampal theta-gamma rhythms at the time of retrieval is a specific reconsolidation marker.SIGNIFICANCE STATEMENT Posttraumatic stress disorder (PTSD) is characterized by maladaptive avoidance responses to stimuli or behaviors that represent or bear resemblance to some aspect of a traumatic experience. Disruption of reconsolidation, the process by which reactivated memories become susceptible to modifications, is a promising approach for treating PTSD patients. However, much of what is known about fear-motivated avoidance memory reconsolidation derives from studies based on fear conditioning instead of avoidance-learning paradigms. Using a step-down inhibitory avoidance task in rats, we found that the hippocampus is involved in memory reconsolidation only when the animals acquired the avoidance response in an environment that they had previously learned as safe and showed that increased theta- and gamma-oscillation coupling during reactivation is an electrophysiological signature of this process.
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Affiliation(s)
- Andressa Radiske
- Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, RN 59056-450 Natal, Brazil
| | - Maria Carolina Gonzalez
- Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, RN 59056-450 Natal, Brazil
| | - Sergio A Conde-Ocazionez
- Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, RN 59056-450 Natal, Brazil
| | - Anatildes Feitosa
- Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, RN 59056-450 Natal, Brazil
| | - Cristiano A Köhler
- Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, RN 59056-450 Natal, Brazil
| | - Lia R Bevilaqua
- Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, RN 59056-450 Natal, Brazil
| | - Martín Cammarota
- Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, RN 59056-450 Natal, Brazil
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Abstract
Early embryos of the clitellate annelid Tubifex (oligochaete) undergo a series of unequal spiral cell divisions before the descendants of the D quadrant micromeres (cells 2d and 4d) divide bilaterally. Here, we show that inhibition of zygotic transcription by microinjection of α-amanitin (transcription inhibitor) exclusively converts unequal cleavage in cell 2d11 (granddaughter of 2d) into equal cleavage while other unequal cleavages and ensuing bilateral cleavages in cells 4d and 2d111 (great-granddaughter of 2d) all proceed in a normal fashion in the presence of this inhibitor. These results differ significantly from those reported for embryos of another clitellate annelid Helobdella (leech), in which inhibition of transcription converts bilateral (symmetric) cleavages in cells DNOPQ"' and DM" (equivalent to 2d111 and 4d) into unequal (asymmetric) cleavages while having no apparent effect on unequal cleavage in DNOPQ" (equivalent to 2d11). These differences imply distinct mechanisms for the control of the unequal-to-bilateral transition in the two clitellate annelids.
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Affiliation(s)
- Momoe Aoki
- Division of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Takashi Shimizu
- Division of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan.
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Abstract
Maternal-to-zygotic transition is an event that developmental control of early embryos is switched from oocyte-derived factors to the zygotic genome. Ability to inhibit DNA replication, transcription, and translation is an important tool in studying events, such as zygotic genome activation, during embyogenesis. Here, we describe approaches to block DNA replication, transcription, and translation using chemical inhibitors. Then we also demonstrate how the transcript level of a maternally inherited gene, ten-eleven translocation methylcytosine dioxygenase 3, responses to the chemical treatments.
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Affiliation(s)
- Kyungjun Uh
- Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Kiho Lee
- Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA, USA.
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Liu Y, Zhang X, Han C, Wan G, Huang X, Ivan C, Jiang D, Rodriguez-Aguayo C, Lopez-Berestein G, Rao PH, Maru DM, Pahl A, He X, Sood AK, Ellis LM, Anderl J, Lu X. TP53 loss creates therapeutic vulnerability in colorectal cancer. Nature 2015; 520:697-701. [PMID: 25901683 PMCID: PMC4417759 DOI: 10.1038/nature14418] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 03/17/2015] [Indexed: 12/26/2022]
Abstract
TP53, a well-known tumour suppressor gene that encodes p53, is frequently inactivated by mutation or deletion in most human tumours. A tremendous effort has been made to restore p53 activity in cancer therapies. However, no effective p53-based therapy has been successfully translated into clinical cancer treatment owing to the complexity of p53 signalling. Here we demonstrate that genomic deletion of TP53 frequently encompasses essential neighbouring genes, rendering cancer cells with hemizygous TP53 deletion vulnerable to further suppression of such genes. POLR2A is identified as such a gene that is almost always co-deleted with TP53 in human cancers. It encodes the largest and catalytic subunit of the RNA polymerase II complex, which is specifically inhibited by α-amanitin. Our analysis of The Cancer Genome Atlas (TCGA) and Cancer Cell Line Encyclopedia (CCLE) databases reveals that POLR2A expression levels are tightly correlated with its gene copy numbers in human colorectal cancer. Suppression of POLR2A with α-amanitin or small interfering RNAs selectively inhibits the proliferation, survival and tumorigenic potential of colorectal cancer cells with hemizygous TP53 loss in a p53-independent manner. Previous clinical applications of α-amanitin have been limited owing to its liver toxicity. However, we found that α-amanitin-based antibody-drug conjugates are highly effective therapeutic agents with reduced toxicity. Here we show that low doses of α-amanitin-conjugated anti-epithelial cell adhesion molecule (EpCAM) antibody lead to complete tumour regression in mouse models of human colorectal cancer with hemizygous deletion of POLR2A. We anticipate that inhibiting POLR2A will be a new therapeutic approach for human cancers containing such common genomic alterations.
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Affiliation(s)
- Yunhua Liu
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Xinna Zhang
- Department of Gynaecologic Oncology and Reproductive Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
- Center for RNA Interference and Non-coding RNAs, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Cecil Han
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Guohui Wan
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Xingxu Huang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Cristina Ivan
- Department of Gynaecologic Oncology and Reproductive Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
- Center for RNA Interference and Non-coding RNAs, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Dahai Jiang
- Department of Gynaecologic Oncology and Reproductive Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
- Center for RNA Interference and Non-coding RNAs, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Cristian Rodriguez-Aguayo
- Center for RNA Interference and Non-coding RNAs, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Gabriel Lopez-Berestein
- Center for RNA Interference and Non-coding RNAs, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Pulivarthi H. Rao
- Department of Paediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Dipen M. Maru
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Andreas Pahl
- Heidelberg Pharma GmbH, Ladenburg 68526, Germany
| | - Xiaoming He
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio 43210, USA
| | - Anil K. Sood
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
- Department of Gynaecologic Oncology and Reproductive Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
- Center for RNA Interference and Non-coding RNAs, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Lee M. Ellis
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Jan Anderl
- Heidelberg Pharma GmbH, Ladenburg 68526, Germany
| | - Xiongbin Lu
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
- Center for RNA Interference and Non-coding RNAs, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
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12
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Lee KB, Folger JK, Rajput SK, Smith GW. Temporal regulation of mRNAs for select bone morphogenetic proteins (BMP), BMP receptors and their associated SMAD proteins during bovine early embryonic development: effects of exogenous BMP2 on embryo developmental progression. Reprod Biol Endocrinol 2014; 12:67. [PMID: 25027287 PMCID: PMC4110370 DOI: 10.1186/1477-7827-12-67] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 07/07/2014] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND We previously demonstrated embryotrophic actions of maternal (oocyte-derived) follistatin during bovine early embryogenesis. Classical actions of follistatin are attributed to inhibition of activity of growth factors including activins and bone morphogenetic proteins (BMP). However, temporal changes in BMP mRNA in early bovine embryos and the effects of exogenous BMP on embryo developmental progression are not understood. The objectives of present studies were to characterize mRNA abundance for select BMP, BMP receptors and BMP receptor associated SMADs during bovine oocyte maturation and early embryogenesis and determine effects of addition of exogenous BMP protein on early development. METHODS Relative abundance of mRNA for BMP2, BMP3, BMP7, BMP10, SMAD1, SMAD5, ALK3, ALK6, ALK2, BMPR2, ACVR2A and ACVR2B was determined by RT-qPCR analysis of germinal vesicle (GV) and in vitro matured metaphase II (MII) oocytes and in vitro produced embryos collected at pronuclear, 2-cell (C), 4C, 8C, 16C, morula and blastocyst stages. Effects of addition of recombinant human BMP2 (0, 1, 10 and 100 ng/ml) during initial 72 h of embryo culture on early cleavage (within 30 h post insemination), total cleavage, development to 8C-16C and blastocyst stages and blastocyst mRNA abundance for markers of inner cell mass (NANOG) and trophectoderm (CDX2) were also determined. RESULTS Abundance of mRNA for BMP2, BMP10, SMAD1, SMAD5, ALK3, ALK2, BMPR2 and ACVR2B was elevated in MII oocytes and/or pronuclear stage embryos (relative to GV) and remained elevated through the 8C -16C stages, whereas BMP3, BMP7 and ALK2 mRNAs were transiently elevated. Culture of embryos to the 8C stage in the presence of α-amanitin resulted in increased abundance for all of above transcripts examined relative to untreated 8C embryos. Effects of addition of exogenous BMP2 on early cleavage rates and rates of development to 8C-16C and blastocyst stages were not observed, but BMP2 treatment increased blastocyst mRNA for CDX2 and NANOG. CONCLUSIONS Abundance of maternally derived mRNAs for above BMP system components are dynamically regulated during oocyte maturation and early embryogenesis. Exogenous BMP2 treatment does not influence progression to various developmental endpoints, but impacts characteristics of resulting blastocysts. Results support a potential role for BMPs in bovine early embryogenesis.
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Affiliation(s)
- Kyung-Bon Lee
- Department of Laboratory of Mammalian Reproductive Biology and Genomics, Michigan State University, East Lansing, MI 48824, USA
- Department of Animal Science, Michigan State University, East Lansing, MI 48824, USA
- Department of Biology Education, College of Education, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Joseph K Folger
- Department of Laboratory of Mammalian Reproductive Biology and Genomics, Michigan State University, East Lansing, MI 48824, USA
- Department of Animal Science, Michigan State University, East Lansing, MI 48824, USA
| | - Sandeep K Rajput
- Department of Laboratory of Mammalian Reproductive Biology and Genomics, Michigan State University, East Lansing, MI 48824, USA
- Department of Animal Science, Michigan State University, East Lansing, MI 48824, USA
| | - George W Smith
- Department of Laboratory of Mammalian Reproductive Biology and Genomics, Michigan State University, East Lansing, MI 48824, USA
- Department of Animal Science, Michigan State University, East Lansing, MI 48824, USA
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
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13
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Bernadotte A, Mikhel'son VM, Spivak IM, Ryzhak GA. [The influence of age of donors on the ability of cells to homologous recombination DNA repair]. Adv Gerontol 2013; 26:614-619. [PMID: 24738249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Old and young donors cells show different ability to homologous recombination (shown on the first stage--the chromosome transference) in vitro, that we suppose could be the reasons of the genome instability in aging. Homologous recombination, induced by X-radiation, is limited in cells taken from donors older than 70 years. Alpha-amanitin, the RNA-polymerize II repressor, in toxic doze, could induce the chromosome transference in the cells from all studied groups: from old and young donors and donors with repair process defect (with BRCA 1, 2 mutations). Summarized effect of X-radiation and alpha-amanitin does not increase the induction of the chromosome transference.
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14
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Gandhi M, Evdokimova VN, T.Cuenco K, Nikiforova MN, Kelly LM, Stringer JR, Bakkenist CJ, Nikiforov YE. Homologous chromosomes make contact at the sites of double-strand breaks in genes in somatic G0/G1-phase human cells. Proc Natl Acad Sci U S A 2012; 109:9454-9. [PMID: 22645362 PMCID: PMC3386068 DOI: 10.1073/pnas.1205759109] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [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] [Indexed: 12/22/2022] Open
Abstract
Double-strand DNA breaks (DSBs) are continuously induced in cells by endogenously generated free radicals and exogenous genotoxic agents such as ionizing radiation. DSBs activate the kinase activity in sensor proteins such as ATM and DNA-PK, initiating a complex DNA damage response that coordinates various DNA repair pathways to restore genomic integrity. In this study, we report the unexpected finding that homologous chromosomes contact each other at the sites of DSBs induced by either radiation or the endonuclease I-PpoI in human somatic cells. Contact involves short segments of homologous chromosomes and is centered on a DSB in active genes but does not occur at I-PpoI sites in intergenic DNA. I-PpoI-induced contact between homologous genes is abrogated by the transcriptional inhibitors actinomycin D and α-amanitin and requires the kinase activity of ATM but not DNA-PK. Our findings provide documentation of a common transcription-related and ATM kinase-dependent mechanism that induces contact between allelic regions of homologous chromosomes at sites of DSBs in human somatic cells.
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Affiliation(s)
- Manoj Gandhi
- Department of Pathology and Laboratory Medicine, University of Pittsburgh, Pittsburgh, PA 15213
| | - Viktoria N. Evdokimova
- Department of Pathology and Laboratory Medicine, University of Pittsburgh, Pittsburgh, PA 15213
| | - Karen T.Cuenco
- Department of Oral Biology, School of Dental Medicine and
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15219
| | - Marina N. Nikiforova
- Department of Pathology and Laboratory Medicine, University of Pittsburgh, Pittsburgh, PA 15213
| | - Lindsey M. Kelly
- Department of Pathology and Laboratory Medicine, University of Pittsburgh, Pittsburgh, PA 15213
| | - James R. Stringer
- Department of Molecular Genetics, University of Cincinnati, Cincinnati, OH 45267; and
| | - Christopher J. Bakkenist
- Department of Molecular Genetics, University of Cincinnati, Cincinnati, OH 45267; and
- Departments of Radiation Oncology and Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15213
| | - Yuri E. Nikiforov
- Department of Pathology and Laboratory Medicine, University of Pittsburgh, Pittsburgh, PA 15213
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15
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Abstract
Epstein-Barr virus (EBV) is a ubiquitous human herpesvirus implicated in lymphomas, such as Burkitt's lymphoma, Hodgkin's lymphoma, and NK/T cell lymphoma. MicroRNAs (miRNAs) are 19-25 nucleotide long single-stranded RNAs involved in post-transcriptional gene regulation. miRNAs are mainly transcribed by RNA polymerase II (pol II) to have stem-loop structures and subsequently processed by Drosha and Dicer. EBV miRNAs are expressed in B cells, nasopharyngeal carcinoma cells, and gastric carcinoma cells infected with EBV. EBV miRNAs can be divided into two groups: BHRF1 miRNAs and BART miRNAs. In this study, we investigated the biogenesis of EBV miRNAs. Treatment of the SNU-719 EBV-positive gastric cancer cell line with α-amanitin at a concentration that selectively inhibits RNA polymerase II activity decreased the expression levels of BART miRNAs. The expression levels of BART miRNAs were also reduced by RNA interference targeting Drosha and Dicer. Two of each C/EBPβ and c-Myc binding sites are located upstream of the proposed initiation sites for primary BART miRNA transcripts. Knockdown of C/EBPβ but not c-Myc using siRNAs reduced BART miRNA expression by 25-55% compared with the control. These results suggest that BART miRNAs are transcribed by pol II and undergo a similar biogenesis process with cellular miRNAs.
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Affiliation(s)
- Do Nyun Kim
- Department of Medical Lifescience, Research Institute of Immunobiology, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul 137-701, Republic of Korea
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16
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Tsao DC, Park NJ, Nag A, Martinson HG. Prolonged α-amanitin treatment of cells for studying mutated polymerases causes degradation of DSIF160 and other proteins. RNA 2012; 18:222-229. [PMID: 22194310 PMCID: PMC3264909 DOI: 10.1261/rna.030452.111] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 11/04/2011] [Indexed: 05/31/2023]
Abstract
A useful method for studying the function of the mammalian RNA polymerase II takes advantage of the extreme sensitivity of its largest subunit, Rpb1, to α-amanitin. Mutations of interest are introduced into an α-amanitin-resistant version of Rpb1, which is then expressed ectopically in cells. The phenotypes of these cells are then examined after inhibiting the endogenous wild-type polymerase with α-amanitin. Here, we show that cells that are enabled to grow in α-amanitin by expression of an α-amanitin-resistant Rpb1 exhibit changes in cell physiology that can lead to misleading experimental outcomes. The changes we have characterized include the accelerated degradation of some proteins, such as DSIF160, and the reduced rate of synthesis of others. In one series of experiments, we examined an α-amanitin-resistant construct, with a mutant C-terminal domain (CTD), that was unable to direct poly(A)-dependent transcription termination in cells growing in α-amanitin. The potential interpretation that the termination defect in this construct is due to the mutation in the CTD was rejected when the construct was found to be termination-competent in cells grown in the absence of α-amanitin. Instead, it appears that certain termination factors become limiting when the cells are grown in α-amanitin, presumably due to the α-amanitin-induced degradation we have characterized and/or to the inadequate transcription of certain genes by the α-amanitin-resistant Rpb1-containing polymerase.
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Affiliation(s)
- David C. Tsao
- Department of Chemistry and Biochemistry, and the Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California 90095-1569, USA
| | - Noh Jin Park
- Department of Chemistry and Biochemistry, and the Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California 90095-1569, USA
| | - Anita Nag
- Department of Chemistry and Biochemistry, and the Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California 90095-1569, USA
| | - Harold G. Martinson
- Department of Chemistry and Biochemistry, and the Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California 90095-1569, USA
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Stump AD, Jablonski SE, Bouton L, Wilder JA. Distribution and mechanism of α-amanitin tolerance in mycophagous Drosophila (Diptera: Drosophilidae). Environ Entomol 2011; 40:1604-1612. [PMID: 22217779 DOI: 10.1603/en11136] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Many mycophagous species of Drosophila can tolerate the mushroom poison α-amanitin in wild mushrooms and in artificial diet. We conducted feeding assays with sixteen Drosophila species and α-amanitin in artificial diet to better determine the phylogenetic distribution of this tolerance. For eight tolerant and one related susceptible species, we sequenced the gene encoding the large subunit of RNA Polymerase II, which is the target site of α-amanitin. We found no differences in the gene that could account for differences in susceptibility to the toxin. We also conducted feeding assays in which α-amanitin was combined with chemical inhibitors of cytochrome P450s or glutathione S-transferases (GSTs) in artificial diet to determine if either of these enzyme families is involved in tolerance to α-amanitin. We found that an inhibitor of GSTs did not reduce tolerance to α-amanitin, but that an inhibitor of cytochrome P450s reduced tolerance in several species. It is possible that the same cytochrome P450 activity that produces tolerance of α-amanitin might produce tolerance of other mushroom toxins as well. If so, a general detoxification mechanism based on cytochrome P450s might answer the question of how tolerance to α-amanitin arose in mycophagous Drosophila when this toxin is found in relatively few mushrooms.
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Affiliation(s)
- Aram D Stump
- Department of Biology, Science Bldg., Room 103, Adelphi University, Garden City, New York 11530, USA.
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18
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Dezitter X, Masselot B, Tardivel M, Mereau-Richard C, Formstecher P, Idziorek T. Macromolecular synthesis inhibitors perturb glucocorticoid receptor trafficking. J Steroid Biochem Mol Biol 2011; 126:104-12. [PMID: 21569845 DOI: 10.1016/j.jsbmb.2011.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 04/21/2011] [Accepted: 04/22/2011] [Indexed: 11/17/2022]
Abstract
The ability of inhibitors of transcription and translation to prevent glucocorticoid-induced apoptosis has been interpreted to indicate that the cell death machinery requires de novo protein synthesis. The transcriptional inhibitors actinomycin D (Act D) and DRB as well as the translational inhibitors CHX and puromycin inhibited early loss of mitochondrial membrane integrity in a dose-dependent manner. This effect was not observed with the transcriptional inhibitor α-amanitin suggesting they may have additional effects. Their role in the glucocorticoid receptor (GR) intracellular trafficking was therefore investigated. Here, we show that Act D and CHX reduced glucocorticoid binding, GR turnover and impaired GR nuclear translocation. We performed the same experiments in different thymocyte subpopulations of Balb/c mice. At the highest dose tested, actinomycin D and cycloheximide abolished glucocorticoid-induced cell death of CD4+CD8+ and CD4+CD8-. In all subsets, Act D, DRB, as well as CHX and puromycin prevented receptor nuclear translocation, indicating a general alteration of GR trafficking. Overall, our data support a direct effect of macromolecular inhibitors on GR activation and trafficking. Finally, direct alterations of the functional properties of the glucocorticoid receptor might be responsible for cell death prevention by actinomycin D, DRB, cycloheximide and puromycin.
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19
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Abstract
Background Gene activation is thought to occur through a series of temporally defined regulatory steps. However, this process has not been completely evaluated in single living mammalian cells. Methodology/Principal Findings To investigate the timing and coordination of gene activation events, we tracked the recruitment of GCN5 (histone acetyltransferase), RNA polymerase II, Brd2 and Brd4 (acetyl-lysine binding proteins), in relation to a VP16-transcriptional activator, to a transcription site that can be visualized in single living cells. All accumulated rapidly with the VP16 activator as did the transcribed RNA. RNA was also detected at significantly more transcription sites in cells expressing the VP16-activator compared to a p53-activator. After α-amanitin pre-treatment, the VP16-activator, GCN5, and Brd2 are still recruited to the transcription site but the chromatin does not decondense. Conclusions/Significance This study demonstrates that a strong activator can rapidly overcome the condensed chromatin structure of an inactive transcription site and supercede the expected requirement for regulatory events to proceed in a temporally defined order. Additionally, activator strength determines the number of cells in which transcription is induced as well as the extent of chromatin decondensation. As chromatin decondensation is significantly reduced after α-amanitin pre-treatment, despite the recruitment of transcriptional activation factors, this provides further evidence that transcription drives large-scale chromatin decondensation.
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Affiliation(s)
- Ilona U. Rafalska-Metcalf
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - Sara Lawrence Powers
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - Lucy M. Joo
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - Gary LeRoy
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Susan M. Janicki
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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20
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Qu LY, Jiang YL, Tang XW. [Effect of DRB/alpha-Amanitin on localization of Nrf2 in A549 cells]. Zhejiang Da Xue Xue Bao Yi Xue Ban 2010; 39:24-29. [PMID: 20175232 DOI: 10.3785/j.issn.1008-9292.2010.01.005] [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: 05/28/2023]
Abstract
OBJECTIVE To investigate the effects of transcriptional inhibitors 5, 6-dichloro-1-b-D-ribofuranosylbenzimidazole (DRB) and alpha-Amanitin on the localization of Nrf2 in the nucleus. METHODS A549 cells were treated with DRB (50 mg/L) or alpha-Amanitin (2.5 mg/L)for 1 h and 6 h in serum-free medium, respectively. The expressions of Nrf2, HO-1, NQO1 and AKR1C were detected by Western blotting analysis. The localization of Nrf2 was determined by laser scanning confocal microscopy after cells were treated with either DRB or agr:-Amanitin for 1 h. RESULTS The expressions of Nrf2 and Nrf2-ARE gene batteries HO-1, AKR1C and NQO1 were decreased after 6 h treated with either DRB or alpha-Amanitin. The expression of SC35 was up-regulated but RNA Pol II was down-regulated; Y12 and NPC did not significantly change. The localization of Nrf2 in the cell nucleus did not change significantly. CONCLUSION DRB and alpha-Amanitin can down-regulate the expression of Nrf2 and its targeting proteins HO-1, AKR1C and NQO1, but may have no effect on the localization of Nrf2.
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Affiliation(s)
- Li-yan Qu
- Department of Biochemistry and Genetics, College of Medicine, Zhejiang University, Hangzhou, China
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21
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Pliss A, Malyavantham K, Bhattacharya S, Zeitz M, Berezney R. Chromatin dynamics is correlated with replication timing. Chromosoma 2009; 118:459-70. [PMID: 19296120 DOI: 10.1007/s00412-009-0208-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [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: 12/04/2008] [Revised: 03/03/2009] [Accepted: 03/03/2009] [Indexed: 01/21/2023]
Abstract
Discrete chromatin domains (ChrD), containing an average of approximately 1 Mbp DNA, represent the basic structural units for the regulation of DNA organization and replication in situ. In this study, a bio-computational approach is employed to simultaneously measure the translational motion of large populations of ChrD in the cell nucleus of living cells. Both movement and configurational changes are strikingly higher in early S-phase replicating ChrD compared to those that replicate in mid and late S-phase. The chromatin dynamics was not sensitive to transcription inhibition by alpha-amanitin but was significantly reduced by actinomycin D treatment. Since a majority of active genes replicate in early S-phase, our results suggest a correlation between levels of chromatin dynamics and chromatin poised for active transcription. Analysis of ChrD colocalization with transcription sites and cDNA with ChrD and transcription sites further supports this proposal.
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Affiliation(s)
- Artem Pliss
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
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22
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Mtango NR, Potireddy S, Latham KE. Expression of microRNA processing machinery genes in rhesus monkey oocytes and embryos of different developmental potentials. Mol Reprod Dev 2009; 76:255-69. [PMID: 18646051 PMCID: PMC2631102 DOI: 10.1002/mrd.20950] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [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] [Indexed: 12/21/2022]
Abstract
MicroRNAs (miRNAs) are a class of small RNAs that silence gene expression. In animal cells, miRNAs bind to the 3' untranslated regions of specific mRNAs and inhibit their translation. The correct regulation of mRNA expression by miRNAs is believed to be important for oocyte maturation, early development and implantation. We examined the expression of 25 mRNAs involved in the microRNA processing pathway in a nonhuman primate oocyte and embryo model. We observed that mRNAs related to miRNA splicing are downregulated during oocyte maturation while those related to miRNA processing are upregulated, indicating that there may exist a temporal difference in their activities related to transcriptional activity in germinal vesicle stage oocytes. We also observed that the vast majority of mRNAs examined were insensitive to alpha-amanitin at the 8-16 cell stage. The expression data did not reveal a major impact of embryo culture, and hormonal stimulation protocol affected only a small number of mRNAs, suggesting that the components of the pathway may be accumulated in the oocyte during oogenesis and resistant to exogenous insults. In comparison to published mouse array data, we observed species differences and similarities in the temporal expression patterns of some genes, suggesting that miRNA processing may be regulated differently. These data extend our understanding of the potential roles of miRNA during primate embryogenesis.
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Affiliation(s)
- Namdori R Mtango
- The Fels Institute for Cancer Research and Molecular Biology, Temple University Medical School, Philadelphia, Pennsylvania 19140, USA
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23
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Dibner C. On the robustness of mammalian circadian oscillators. Cell Cycle 2009; 8:681-682. [PMID: 19223765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
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24
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Wu MC, Lu KH. Juvenile hormone induction of glutathione S-transferase activity in the larval fat body of the common cutworm, Spodoptera litura (Lepidoptera: Noctuidae). Arch Insect Biochem Physiol 2008; 68:232-240. [PMID: 18618763 DOI: 10.1002/arch.20257] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The effect of pyriproxyfen, a juvenile hormone analog (JHA), on the pupation of S. litura was examined. A topical application of 100 mug JHA/larva on the newly ecdysed (0-day) sixth instar larvae resulted in more than 80% pupation, while most of the 1- or 2-day-old larvae similarly treated developed into supernumerary larvae. Glutathione S-transferse (GST) activity in the fat body of 0-day-old sixth instar larvae was significantly induced within 12 h of JHA (100 microg/larva) treatment. In contrast, no such induction was found when 1- and 2-day-old sixth instar larvae were similarly treated. This induction phenomenon was also observed when 0-day-old sixth instar larvae were treated with the natural JH III. The suppressive effects of alpha-amanitin and cycloheximide suggest that JHA induction of GST activity in these cutworm larvae presumably occurred at the gene transcription level.
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Affiliation(s)
- Ming-Cheng Wu
- Department of Entomology, National Chung-Hsing University, Taiwan, ROC
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Listerman I, Bledau AS, Grishina I, Neugebauer KM. Extragenic accumulation of RNA polymerase II enhances transcription by RNA polymerase III. PLoS Genet 2008; 3:e212. [PMID: 18039033 PMCID: PMC2082468 DOI: 10.1371/journal.pgen.0030212] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Accepted: 10/10/2007] [Indexed: 11/25/2022] Open
Abstract
Recent genomic data indicate that RNA polymerase II (Pol II) function extends beyond conventional transcription of primarily protein-coding genes. Among the five snRNAs required for pre-mRNA splicing, only the U6 snRNA is synthesized by RNA polymerase III (Pol III). Here we address the question of how Pol II coordinates the expression of spliceosome components, including U6. We used chromatin immunoprecipitation (ChIP) and high-resolution mapping by PCR to localize both Pol II and Pol III to snRNA gene regions. We report the surprising finding that Pol II is highly concentrated ∼300 bp upstream of all five active human U6 genes in vivo. The U6 snRNA, an essential component of the spliceosome, is synthesized by Pol III, whereas all other spliceosomal snRNAs are Pol II transcripts. Accordingly, U6 transcripts were terminated in a Pol III-specific manner, and Pol III localized to the transcribed gene regions. However, synthesis of both U6 and U2 snRNAs was α-amanitin-sensitive, indicating a requirement for Pol II activity in the expression of both snRNAs. Moreover, both Pol II and histone tail acetylation marks were lost from U6 promoters upon α-amanitin treatment. The results indicate that Pol II is concentrated at specific genomic regions from which it can regulate Pol III activity by a general mechanism. Consequently, Pol II coordinates expression of all RNA and protein components of the spliceosome. During transcription, RNA polymerases synthesize an RNA copy of a given gene. Human genes are transcribed by either RNA polymerase I, II, or III. Here, we focus on transcription of the U6 gene that encodes a small nuclear RNA (snRNA), a non-coding RNA with unique activities in gene expression. The U6 snRNA is transcribed by RNA polymerase III (Pol III); here we report the surprising finding that RNA polymerase II (Pol II) is important for efficient expression of the U6 snRNA. Interestingly, high concentrations of Pol II have been recently observed on genomic regions that are considered outside of transcribed genes. We localized Pol II to a region upstream of the U6 snRNA gene promoters in living cells. Inhibition of Pol II activity decreased U6 snRNA synthesis and was accompanied by a decrease in Pol II accumulation as well as transcription-activating histone modifications, while Pol III remained bound at U6 genes. Thus, Pol II may promote U6 snRNA transcription by facilitating open chromatin formation. Our results provide insight into the extragenic function of Pol II, which can coordinate the expression of all components of the RNA splicing machinery, including U6 snRNA.
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Affiliation(s)
- Imke Listerman
- Max-Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Anita S Bledau
- Max-Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Inna Grishina
- Max-Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Karla M Neugebauer
- Max-Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- * To whom correspondence should be addressed. E-mail:
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26
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Abstract
Toxoplasma gondii GRA10 expressed as a GFP-GRA10 fusion protein in HeLa cells moved to the nucleoli within the nucleus rapidly and entirely. GRA10 was concentrated specifically in the dense fibrillar component of the nucleolus morphologically by the overlap of GFP-GRA10 transfection image with IFA images by monoclonal antibodies against GRA10 (Tg378), B23 (nucleophosmin) and C23 (nucleolin). The nucleolar translocalization of GRA10 was caused by a putative nucleolar localizing sequence (NoLS) of GRA10. Interaction of GRA10 with TATA-binding protein associated factor 1B (TAF1B) in the yeast two-hybrid technique was confirmed by GST pull-down assay and immunoprecipitation assay. GRA10 and TAF1B were also co-localized in the nucleolus after co-transfection. The nucleolar condensation of GRA10 was affected by actinomycin D. Expressed GFP-GRA10 was evenly distributed over the nucleoplasm and the nucleolar locations remained as hollows in the nucleoplasm under a low dose of actinomycin D. Nucleolar localizing and interacting of GRA10 with TAF1B suggested the participation of GRA10 in rRNA synthesis of host cells to favor the parasitism of T. gondii.
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Affiliation(s)
- Hye-Jin Ahn
- Department of Parasitology and the Catholic Institute of Parasitic Diseases, College of Medicine, Catholic University of Korea, Seoul 137-701, Korea
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27
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Da Silva WC, Bonini JS, Bevilaqua LRM, Medina JH, Izquierdo I, Cammarota M. Inhibition of mRNA synthesis in the hippocampus impairs consolidation and reconsolidation of spatial memory. Hippocampus 2007; 18:29-39. [PMID: 17853412 DOI: 10.1002/hipo.20362] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [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: 12/30/2022]
Abstract
Using two different mRNA synthesis inhibitors, we show that blockade of hippocampal gene expression during restricted posttraining or postretrieval time windows hinders retention of long-term spatial memory for the Morris water maze task, without affecting short-term memory, nonspatial learning, or the functionality of the hippocampus. Our results indicate that spatial memory consolidation induces the activation of the hippocampal transcriptional machinery and suggest the existence of a gene expression-dependent reconsolidation process that operates in the dorsal hippocampus at the moment of retrieval to stabilize the reactivated mnemonic trace.
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Affiliation(s)
- Weber C Da Silva
- Centro de Memória, Instituto de Pesquisas Biomédicas, Pontifícia Universidade Católica do Rio Grande do Sul, Av. Ipiranga 6690, Porto Alegre, Rio Grande do Sul, Brasil
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28
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Meglicki M, Zientarski M, Borsuk E. Constitutive heterochromatin during mouse oogenesis: The pattern of histone H3 modifications and localization of HP1α and HP1β proteins. Mol Reprod Dev 2007; 75:414-28. [PMID: 17891782 DOI: 10.1002/mrd.20772] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [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: 11/10/2022]
Abstract
Centromeres are the fragments of DNA that are responsible for proper chromosome segregation. They consist of centromeric chromatin surrounded by blocks of pericentric heterochromatin, playing an important role in centromere function. In somatic cells, the pericentric domains have a specific pattern of epigenetic modifications of core histones and contain specific pericentric proteins. These features are probably more important for the centromere function than the sequence of the centromeric DNA itself. In somatic cells, the HP1alpha and HP1beta proteins are indispensable for constitutive heterochromatin formation and maintenance. We have analyzed the localization of these proteins in the primordial, growing, fully-grown, and maturing mouse oocytes. Additionally, we have analyzed post-translational modifications of histone H3, which can influence HP1alpha and HP1beta association with the heterochromatin. We showed that the regions of constitutive heterochromatin have a distinct pattern of histone H3 acetylation and di-, and trimethylation of its lysine 9. We demonstrated that HP1beta protein was present in pericentric chromatin domains in primordial oocytes, growing (transcriptionally active) oocytes, and in fully-grown oocytes, and was released to the cytoplasm after germinal vesicle breakdown. In contrast, the HP1alpha was never detected in primordial oocytes, was first detected in pericentric heterochromatin in growing oocytes, dissociated from pericentric heterochromatin in fully-grown oocytes, and it was never detected in maturing oocytes. The presence of HP1alpha and HP1beta proteins on the heterochromatin of transcriptionally active oocytes and their absence in transcriptionally silent oocytes suggest that they are necessary for the repression of RNA synthesis in heterochromatin domains of transcribing oocytes.
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Affiliation(s)
- Maciej Meglicki
- Department of Embryology, Institute of Zoology, University of Warsaw, Warsaw, Poland
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