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Blich M, Zohar Y, Cohen-Kaplan V, Minkov I, Asleh R, Horowitz-Cederboim S, Weiss K, Paperna T, Lessick J, Abadi S, Khoury A, Gepstein L, Suleiman M, Caspi O. Ser194Leu DSG2 mutation, associated with arrhythmogenic left ventricular cardiomyopathy and ventricular tachycardia. Pacing Clin Electrophysiol 2024; 47:503-510. [PMID: 38375917 DOI: 10.1111/pace.14950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 01/25/2024] [Accepted: 01/30/2024] [Indexed: 02/21/2024]
Abstract
INTRODUCTION Arrhythmogenic cardiomyopathy (AC) is an inherited cardiomyopathy characterized by fibro-fatty replacement of cardiomyocytes, leading to life-threatening ventricular arrhythmia and heart failure. Pathogenic variants of desmoglein2 gene (DSG2) have been reported as genetic etiologies of AC. In contrast, many reported DSG2 variants are benign or variants of uncertain significance. Correct genetic variant classification is crucial for determining the best medical therapy for the patient and family members. METHODS Pathogenicity of the DSG2 Ser194Leu variant that was identified by whole exome sequencing in a patient, who presented with ventricular tachycardia and was diagnosed with AC, was investigated by electron microscopy and immunohistochemical staining of endomyocardial biopsy sample. RESULTS Electron microscopy demonstrated a widened gap in the adhering junction and a less well-organized intercalated disk region in the mutated cardiomyocytes compared to the control. Immunohistochemical staining in the proband diagnosed with AC showed reduced expression of desmoglein 2 and connexin 43 and intercalated disc distortion. Reduced expression of DSG2 and Connexin 43 were observed in cellular cytoplasm and gap junctions. Additionally, we detected perinuclear accumulation of DSG2 and Connexin 43 in the proband sample. CONCLUSION Ser194Leu is a missense pathogenic mutation of DSG2 gene associated with arrhythmogenic left ventricular cardiomyopathy.
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Affiliation(s)
- Miry Blich
- Cardiology Division, Rambam Health Care Campus, Haifa, Israel
| | - Yaniv Zohar
- Department of Pathology, Rambam Health Care Campus, Haifa, Israel
| | - Victoria Cohen-Kaplan
- Bruce Rappaport School of Medicine, Technion Israel Institute of Technology, Haifa, Israel
| | - Irina Minkov
- Department of Pathology, Rambam Health Care Campus, Haifa, Israel
| | - Rabea Asleh
- Heart Institute, Hadassah Medical Center, Jerusalem, Israel
| | | | - Karin Weiss
- The Genetics Institute, Rambam Health Care Campus, Haifa, Israel
| | - Tamar Paperna
- The Genetics Institute, Rambam Health Care Campus, Haifa, Israel
| | | | - Sobhi Abadi
- Medical Imaging Departments, Rambam Health Care Campus, Haifa, Israel
| | - Asaad Khoury
- Cardiology Division, Rambam Health Care Campus, Haifa, Israel
| | - Lior Gepstein
- Cardiology Division, Rambam Health Care Campus, Haifa, Israel
| | - Mahmud Suleiman
- Cardiology Division, Rambam Health Care Campus, Haifa, Israel
| | - Oren Caspi
- Cardiology Division, Rambam Health Care Campus, Haifa, Israel
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Daskalova E, Dontcheva S, Zekaj Z, Bacu A, Sota V, Abdullai K, Gashi B, Minkov I, Toneva V, Kongjika E. Initial Determination of Polymorphism andIn VitroConservation of SomeRamonda SerbicaandRamonda NathaliaePopulations from Albania, Macedonia and Bulgaria. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.5504/50yrtimb.2011.0004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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3
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Radeva V, Petrov V, Minkov I, Toneva V, Gechev T. Effect of Cadmium onArabidopsis ThalianaMutants Tolerant to Oxidative Stress. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.1080/13102818.2010.10817823] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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Valcheva R, Yungareva T, Kirilov N, Dobreva G, Minkov I, Ivanova I. Proteolytic and Phytase Activity in Sourdough Lactic Acid Bacteria. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.1080/13102818.2009.10818512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Daskalova E, Dontcheva S, Yahubyan G, Minkov I, Toneva V. Ecological Characteristics and Conservation of the Protected Resurrection SpeciesHaberlea Rhodopensis Friv.asIn VitroPlants Through a Modified Micropropagation System. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.1080/13102818.2010.10817838] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Naimov S, Zahmanova G, Boncehva R, Kostova M, Minkov I, Dukiandjiev S, de Maagd R. Expression of Synthetic SN 19 Hybrid Delta-Endotoxin Encoding Gene in Transgenic Potato. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.1080/13102818.2006.10817378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Dontcheva S, Daskalova E, Yahubyan G, Denev I, Minkov I, Toneva V. Conservation of the Protected Resurection SpeciesRamonda SerbicaPanč.—Habitat Montana District, Bulgaria asIn Vitro, Plants Through a Modified Micropropagation System. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.1080/13102818.2009.10818441] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Daskalova E, Dontcheva S, Kadieva I, Gevezova M, Toneva V, Minkov I, Denev I. Assessment of Genetic Diversity of Haberlea RhodopensisFriv. by ITS1 Markers. BIOTECHNOL BIOTEC EQ 2012. [DOI: 10.5504/50yrtimb.2011.0005] [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: 11/27/2022] Open
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Vachev T, Ivanova D, Minkov I, Tsagris M, Gozmanova M. Trafficking of the Potato spindle tuber viroid between tomato and Orobanche ramosa. Virology 2010; 399:187-93. [DOI: 10.1016/j.virol.2009.12.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 08/11/2009] [Accepted: 12/12/2009] [Indexed: 10/19/2022]
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Ivanova D, Vachev T, Baev V, Minkov I, Gozmanova M. Identification of Potato Spindle Tuber Viroid Small RNA in Orobanche Ramosaby Microarray. BIOTECHNOL BIOTEC EQ 2010. [DOI: 10.1080/13102818.2010.10817829] [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: 10/25/2022] Open
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11
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Ueda K, Liu XJ, Prümper G, Lischke T, Tanaka T, Hoshino M, Tanaka H, Minkov I, Kimberg V, Gel’mukhanov F. Role of the recoil effect in two-center interference in X-ray photoionization. Chem Phys 2006. [DOI: 10.1016/j.chemphys.2006.06.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Hennies F, Polyutov S, Minkov I, Pietzsch A, Nagasono M, Gel'mukhanov F, Triguero L, Piancastelli MN, Wurth W, Agren H, Föhlisch A. Nonadiabatic effects in resonant inelastic x-ray scattering. Phys Rev Lett 2005; 95:163002. [PMID: 16241792 DOI: 10.1103/physrevlett.95.163002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Indexed: 05/05/2023]
Abstract
We have studied the spectral features of resonant inelastic x-ray scattering of condensed ethylene with vibrational selectivity both experimentally and theoretically. Purely vibrational spectral loss features and coupled electronic and vibrational losses are observed. The one-step theory for resonant soft x-ray scattering is applied, taking multiple vibrational modes and vibronic coupling into account. Our investigation of ethylene underlines that the assignment of spectral features observed in resonant inelastic x-ray scattering of polyatomic systems requires an explicit description of the coupled electronic and vibrational loss features.
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Affiliation(s)
- F Hennies
- Institut für Experimentalphysik, Universität Hamburg, Germany
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Polyutov S, Minkov I, Gel'mukhanov F, Agren H. Interplay of One- and Two-Step Channels in Electrovibrational Two-Photon Absorption. J Phys Chem A 2005; 109:9507-13. [PMID: 16866401 DOI: 10.1021/jp0536100] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We present a theory of two-photon absorption that addresses the formation of spectral shapes taking the vibrational degrees of freedom into account. The theory is used to rationalize the observed differences between the spectral shapes of one- and two-photon absorption. We find that the main cause of these differences is that the two-step and coherent two-photon spectral bands are different even considering a single final state. Our formalism is applied to the N101 molecule (p-nitro-p'-diphenylamine stilbene), which was recently studied experimentally. Simulations show that the two-step two-photon electrovibrational absorption results in a blue shift of the absorption spectrum in agreement with the measurements.
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Affiliation(s)
- S Polyutov
- Theoretical Chemistry, Roslagstullsbacken 15, Royal Institute of Technology, S-106 91 Stockholm, Sweden.
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Minkov I, Ivanova T, Panaiotov I, Proust J, Saulnier P. Reorganization of lipid nanocapsules at air–water interface. Colloids Surf B Biointerfaces 2005; 45:14-23. [PMID: 16111870 DOI: 10.1016/j.colsurfb.2005.03.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Revised: 02/07/2005] [Accepted: 03/23/2005] [Indexed: 11/16/2022]
Abstract
The size, the electrical properties and the behaviour at air-water interface of lipid nanocapsules (LNC) with various compositions were investigated. Two populations of LNC are presented in the suspension after the preparation: with (LNC II) and without (LNC I) phospholipid molecules. After the spreading at air-water interface, a rapid disaggregation of LNC I, located in the vicinity of interface, occurs leading to formation of surface film. The phospholipid molecules stabilize the structure of nanocapsules and LNC II are more stable at the interface in comparison with LNC I. The formation of a surface film was followed after by measuring the evolution of the surface pressure, relative surface area change and surface potential. A kinetic approach describing the various processes during the surface film formation was proposed. The corresponding kinetic constants were estimated.
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Affiliation(s)
- I Minkov
- Biophysical Chemistry Laboratory, University of Sofia, James Bourchier Str. 1, 1126 Sofia, Bulgaria.
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Minkov I, Ivanova T, Panaiotov I, Proust J, Saulnier P. Reorganization of lipid nanocapsules at air–water interface. Colloids Surf B Biointerfaces 2005; 44:197-203. [PMID: 16081256 DOI: 10.1016/j.colsurfb.2005.07.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2005] [Revised: 06/28/2005] [Accepted: 07/05/2005] [Indexed: 11/23/2022]
Abstract
The state, electrical and dilatational rheological properties of surface films formed at air-water interface from lipid nanocapsules (LNC) with various compositions as well as model monolayers formed by the LNC constituents-Labrafac, Solutol and Lipoid are investigated. These nanocapsules constitute potential drug delivery systems where lypophilic drug will be loaded in their core. The study of the model Labrafac/Solutol (Lab/Sol) mixed monolayers shows behavior close to the ideal. Small negative deviations in the mean molecular areas a and dipole moments mu are observed. All studied monolayers have elastic behavior during the small continuous compressions. The comparison between the properties of surface films formed from LNC with those of the model monolayers confirms the idea developed in the kinetic study that the surface films formed after a rapid disaggregation of the unstable nanocapsule fraction (LNC I) contains mainly Labrafac and Solutol. The Labrafac molar part (xLab) in the formed Lab/Sol mixed layer is established.
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Affiliation(s)
- I Minkov
- University of Sofia, Laboratory of Biophysical Chemistry, James Bourchier str. 1, 1126 Sofia, Bulgaria.
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Minkov I, Ivanova T, Panaiotov I, Proust J, Verger R. Reorganization of lipid nanocapsules at air–water interface. Colloids Surf B Biointerfaces 2005; 45:24-34. [PMID: 16105730 DOI: 10.1016/j.colsurfb.2005.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2005] [Revised: 06/28/2005] [Accepted: 07/05/2005] [Indexed: 11/20/2022]
Abstract
The action of the hydrolytic enzymes humicola lanuginosa lipase (HLL) and pancreatic phospholipase A2 (PLA2) on monolayers formed from lipid nanocapsules (LNC) and model monolayers containing their components, Labrafac, Solutol and Lipoid, is studied by simultaneous measuring the changes in the film area and the surface potential in the "zero order" trough at constant surface pressure (pi). The kinetic models describing the hydrolysis by HLL of the Labrafac, Solutol and their mixtures have been proposed. By using the developed theoretical approach together with the experimental results the surface concentrations of the substrates, hydrolysis products and values of the global kinetic constants were obtained. The comparison between the global kinetic constants in the case of HLL hydrolysis of pure Labrafac, Solutol monolayers and those of the model mixed Labrafac/Solutol monolayers, shows that the rates of hydrolysis are of the same order of magnitude, i.e. an additively of the HLL enzyme action is observed. The composition of the mixed Labrafac/Solutol monolayer, formed after the interfacial LNC destabilization, was estimated.
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Affiliation(s)
- I Minkov
- Biophysical Chemistry Laboratory, University of Sofia, J. Bourchier Str. 1, 1126 Sofia, Bulgaria.
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Felicı́ssimo V, Minkov I, Guimarães F, Gel’mukhanov F, Cesar A, Ågren H. A theoretical study of the role of the hydrogen bond on core ionization of the water dimer. Chem Phys 2005. [DOI: 10.1016/j.chemphys.2004.12.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
High-resolution C(1s) near-edge X-ray absorption and X-ray photoionization spectra of the free biphenyl molecule are presented and theoretically analyzed in order to allow an assignment of the observed spectral features. Finite lifetime broadening, a high density of vibrational states, and a strong overlap of contributions from chemically different carbon atom sites only partially allow resolving the vibrational fine structure. However, the shape and width of the spectral profiles are strongly determined by both chemical shifts and vibronic effects. In particular, different from photoionization of valence levels, both types of core level spectra do not contain contributions from dihedral modes which are related to the twisting motion of the two phenyl rings. Contrary to naphthalene, C-H stretching modes are significantly enhanced in the core excitation spectra of biphenyl while the contributions from C-C stretching modes are reduced.
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Affiliation(s)
- I Minkov
- Theoretical Chemistry, Roslagstullsbacken 15, Royal Institute of Technology, S-106 91 Stockholm, Sweden. ivo@ theochem.kth.se
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Minkov I, Gel'mukhanov F, Friedlein R, Osikowicz W, Suess C, Ohrwall G, Sorensen SL, Braun S, Murdey R, Salaneck WR, Agren H. Core excitations of naphthalene: Vibrational structure versus chemical shifts. J Chem Phys 2004; 121:5733-9. [PMID: 15366997 DOI: 10.1063/1.1784450] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
High-resolution x-ray photoelectron emission (XPS) and near-edge x-ray absorption fine structure (NEXAFS) spectra of naphthalene are analyzed in terms of the initial state chemical shifts and the vibrational fine structure of the excitations. Carbon atoms located at peripheral sites experience only a small chemical shift and exhibit rather similar charge-vibrational coupling, while the atoms in the bridging positions differ substantially. In the XPS spectra, C-H stretching modes provide important contributions to the overall shape of the spectrum. In contrast, the NEXAFS spectrum contains only vibrational progressions from particular C-C stretching modes. The accuracy of ab initio calculations of absolute electronic transition energies is discussed in the context of minute chemical shifts, the vibrational fine structure, and the state multiplicity.
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Affiliation(s)
- I Minkov
- Royal Institute of Technology, S-106 91 Stockholm, Sweden
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Abstract
BACKGROUND Nasopharyngeal carcinoma (NPC) is frequently associated with Epstein-Barr virus (EBV). The incidence of NPC in Western countries is lower than in the Far East, and EBV latency in NPC is less prevalent. Israel, as a part of the Mediterranean area, is one of the countries with an intermediate risk for NPC. METHODS Immunohistochemistry (IHC) for latent membrane protein 1 (LMP-1) and in situ hybridisation (ISH) for EBV encoded RNA (EBER) were used to evaluate the prevalence and possible prognostic value of EBV latency among Israeli patients with NPC. Forty five patients with different NPC histologies were studied. RESULTS LMP-1 IHC was positive in six samples only, all with undifferentiated histology. EBER ISH was positive in 40 of the 45 samples. According to histological type, three of five patients with squamous cell carcinoma were EBV positive and 37 of 40 non-keratinising and undifferentiated carcinoma cases were positive. Although EBV was more prevalent in patients with non-squamous carcinoma, the difference was not significant, probably because of the small number of patients with keratinising carcinoma. With regard to the clinical categories and survival, no significant difference could be detected between patients who were positive or negative for EBER ISH. No association was found between EBV latency and patient sex, age, origin, stage, or survival. CONCLUSIONS NPC in Israel is highly associated with EBV latency as detected by EBER ISH. LMP-1 IHC is considerably less sensitive in detecting EBV latency in NPC among the same patient group.
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Affiliation(s)
- G Bar-Sela
- Department of Oncology, Rambam Medical Centre, PO Box 9602, Haifa 31096, Israel.
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Pantev A, Valcheva R, Danova S, Ivanova I, Minkov I, Haertlé T, Chobert JM. Effect of enterococcin A 2000 on biological and synthetic phospholipid membranes. Int J Food Microbiol 2003; 80:145-52. [PMID: 12381400 DOI: 10.1016/s0168-1605(02)00143-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [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: 11/15/2022]
Abstract
Lactic acid bacterium isolated from Bulgarian cheese and identified as Enterococcus faecium produces a small hydrophobic peptide substance (enterococcin A 2000) with broad spectrum of antimicrobial activity. The wide range of enterococcin antibacterial activity of this compound against Gram-positive, as well as against some Gram-negative bacteria, suggests a single mechanism of action. The mode of action of enterococcin A 2000 was studied in intact liver mitochondria and synthetic phospholipid liposomes used as model systems. Enterococcin A 2000 stimulated the ATPase activity in intact mitochondria. The kinetic curve of ATP hydrolysis differed from that obtained in presence of dinitrophenol (DNP) and showed a character similar to the ATP hydrolysis in the presence of classic ionophores. Enterococcin A 2000, when bound to synthetic phospholipid liposomes, permeabilized liposomes liberating the marker carboxyfluorescein (CF).
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Affiliation(s)
- A Pantev
- Department of Microbiology, Faculty of Biology, University of Sofia, 8 bul. Dragan Tzankov, 1423, Sofia, Bulgaria.
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Gechev T, Gadjev I, Van Breusegem F, Inzé D, Dukiandjiev S, Toneva V, Minkov I. Hydrogen peroxide protects tobacco from oxidative stress by inducing a set of antioxidant enzymes. Cell Mol Life Sci 2002; 59:708-14. [PMID: 12022476 DOI: 10.1007/s00018-002-8459-x] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.0] [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: 10/27/2022]
Abstract
Tolerance against oxidative stress generated by high light intensities or the catalase inhibitor aminotriazole (AT) was induced in intact tobacco plants by spraying them with hydrogen peroxide (H2O2). Stress tolerance was concomitant with an enhanced antioxidant status as reflected by higher activity and/or protein levels of catalase, ascorbate peroxidase, guaiacol peroxidases, and glutathione peroxidase, as well as an increased glutathione pool. The induced stress tolerance was dependent on the dose of H2O2 applied. Moderate doses of H2O2 enhanced the antioxidant status and induced stress tolerance, while higher concentrations caused oxidative stress and symptoms resembling a hypersensitive response. In stress-tolerant plants, induction of catalase was 1.5-fold, that of ascorbate peroxidase and glutathione peroxidase was 2-fold, and that of guaiacol peroxidases was approximately 3-fold. Stress resistance was monitored by measuring levels of malondialdehyde, an indicator of lipid peroxidation. The levels of malondialdehyde in all H2O2-treated plants exposed to subsequent high light or AT stress were similar to those of unstressed plants, whereas lipid peroxidation in H2O2-untreated plants stressed with either high light or AT was 1.5- or 2-fold higher, respectively. Although all stress factors caused increases in the levels of reduced glutathione, its levels were much higher in all H2O2-pretreated plants. Moreover, significant accumulation of oxidized glutathione was observed only in plants that were not pretreated with H2O2. Extending the AT stress period from 1 to 7 days resulted in death of tobacco plants that were not pretreated with H2O2, while all H2O2-pretreated plants remained little affected by the prolonged treatment. Thus, activation of the plant antioxidant system by H2O2 plays an important role in the induced tolerance against oxidative stress.
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Affiliation(s)
- T Gechev
- Department of Plant Physiology and Molecular Biology, Plovdiv University, Bulgaria
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Yahubyan G, Minkov I, Sundqvist C. Carotenoid dependence of the protochlorophyllide to chlorophyllide phototransformation in dark-grown wheat seedlings. J Photochem Photobiol B 2001; 65:171-6. [PMID: 11809376 DOI: 10.1016/s1011-1344(01)00266-4] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The influence of carotenoids on partial protochlorophyllide (Pchlide) photoreduction and the successive formation of long-wavelength chlorophyllide (Chlide) forms was studied by low-temperature fluorescence spectroscopy (77 K). Wheat leaves with a decreased content of carotenoids obtained from norflurazon-treated seedlings (10 and 100 micromol l(-1)) were compared with leaves containing normal amounts of these pigments. Partial photoreduction of Pchlide was achieved by irradiation of the leaves with one light flash in combination with a number of neutral gray and/or red Perspex filters. There were significant differences between the fluorescence emission spectra (the position and height of the peaks) of dark-grown normal and carotenoid-deficient leaves irradiated with non-saturating white light of increasing intensity. The long-wavelength Chlide forms appeared first in the leaves nearly devoid of carotenoids (treated with 100 micromol l(-1) norflurazon), then in the leaves with carotenoid deficiency (treated with 10 micromol l(-1) norflurazon), and finally in normal leaves. After irradiation with non-saturating light of the same intensity, the ratio Chlide/Pchlide(657) was always the highest in the leaves nearly deficient of carotenoids, medium in the leaves with carotenoid deficiency and lowest in the normal leaves. Similarly to white light, red light of low intensity induced faster formation of long-wavelength Chlide species in the leaves with carotenoid deficiency in comparison to the normal leaves. We propose that, in leaves with reduced carotenoid content, a greater number of Pchlide molecules transform to Chlide per light flash than in normal leaves. The results are discussed in relation to the involvement of carotenoids in competitive absorption and light screening, as well as to their influence on Pchlide-Chlide interactions.
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Affiliation(s)
- G Yahubyan
- Department of Plant Physiology and Molecular Biology, University of Plovdiv, Tsar Assen 24 St., 4000 Plovdiv, Bulgaria.
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Iliadi K, Iliadi N, Rashkovetsky E, Minkov I, Nevo E, Korol A. Sexual and reproductive behaviour of Drosophila melanogaster from a microclimatically interslope differentiated population of "Evolution Canyon" (Mount Carmel, Israel). Proc Biol Sci 2001; 268:2365-74. [PMID: 11703877 PMCID: PMC1088888 DOI: 10.1098/rspb.2001.1822] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The strong microscale interslope environmental differences in "Evolution Canyon" provide an excellent natural model for sympatric speciation. Our previous studies revealed significant slope-specific differences for a fitness complex of Drosophila. This complex involved either adaptation traits (tolerance to high temperature, different viability and longevity pattern) or behavioural differentiation, manifested in habitat choice and non-random mating. This remarkable differentiation has evolved despite a very small interslope distance (a few hundred metres only). Our hypothesis is that strong interslope microclimatic contrast caused differential selection for fitness-related traits accompanied by behavioural differentiation and reinforced by some sexual isolation, which started incipient speciation. Here we describe the results of a systematic analysis of sexual behaviour in a non-choice situation and several reproductive parameters of D. melanogaster populations from the opposite slopes of "Evolution Canyon". The evidence indicates that: (i) mate choice derives from differences in mating propensity and discrimination; (ii) females from the milder north-facing slope discriminate strongly against males of the opposite slope; (iii) both sexes of the south-facing slope display distinct reproductive and behavioural patterns with females showing increased fecundity, shorter time before remating and relatively higher receptivity, and males showing higher mating propensity. These patterns represent adaptive life strategies contributing to higher fitness.
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Affiliation(s)
- K Iliadi
- Pavlov Institute of Physiology, Russian Academy of Sciences, St Petersburg 199034, Russia.
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Michalak P, Minkov I, Helin A, Lerman DN, Bettencourt BR, Feder ME, Korol AB, Nevo E. Genetic evidence for adaptation-driven incipient speciation of Drosophila melanogaster along a microclimatic contrast in "Evolution Canyon," Israel. Proc Natl Acad Sci U S A 2001; 98:13195-200. [PMID: 11687637 PMCID: PMC60847 DOI: 10.1073/pnas.231478298] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.6] [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] [Accepted: 09/11/2001] [Indexed: 11/18/2022] Open
Abstract
Substantial genetic differentiation, as great as among species, exists between populations of Drosophila melanogaster inhabiting opposite slopes of a small canyon. Previous work has shown that prezygotic sexual isolation and numerous differences in stress-related phenotypes have evolved between D. melanogaster populations in "Evolution Canyon," Israel, in which slopes 100-400 m apart differ dramatically in aridity, solar radiation, and associated vegetation. Because the canyon's width is well within flies' dispersal capabilities, we examined genetic changes associated with local adaptation and incipient speciation in the absence of geographical isolation. Here we report remarkable genetic differentiation of microsatellites and divergence in the regulatory region of hsp70Ba which encodes the major inducible heat shock protein of Drosophila, in the two populations. Additionally, an analysis of microsatellites suggests a limited exchange of migrants and lack of recent population bottlenecks. We hypothesize that adaptation to the contrasting microclimates overwhelms gene flow and is responsible for the genetic and phenotypic divergence between the populations.
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Affiliation(s)
- P Michalak
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th Street, Chicago, IL 60637-1508, USA
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Jeliazkova V, Minkov I. Effects of Some Organic Solvents on the Activity of the Soluble Acetylcholinesterase from Rat Brain. BIOTECHNOL BIOTEC EQ 1999. [DOI: 10.1080/13102818.1999.10819031] [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: 10/25/2022] Open
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Jeliazkova V, Minkov I. A Simple Method for Isolation of a Soluble Acetylcholinesterase from Rat Brain. BIOTECHNOL BIOTEC EQ 1999. [DOI: 10.1080/13102818.1999.10819045] [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: 10/25/2022] Open
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Simidzhiev I, Kagan VE, Minkov I. [Effect of alpha-tocopherol and its derivatives on ATPase activity and oxidative phosphorylation in rat liver mitochondria]. Biull Eksp Biol Med 1987; 104:299-301. [PMID: 2959331] [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: 01/03/2023]
Abstract
The effects of alpha-tocopherol and its derivatives on the energy metabolism in mitochondria were studied. It was shown that alpha-tocopherol derivatives with short hydrocarbon chain produce uncoupling effects, while alpha-tocopherol itself as well as its long-chain derivatives (tocopheryl acetate and tocopheryl stearate) exert no effect. All the derivatives studied produced an inhibitory effect on DNP-stimulated mitochondrial ATPase. As far as these compounds did not influence the activity of mitochondrial F1 factor, it was concluded that the effects of the compounds were due to membrane modification.
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Tsvetkov T, Tsonev L, Minkov I. A quantitative evaluation of the extent of inner mitochondrial membrane destruction after freezing-thawing based on functional studies. Cryobiology 1986; 23:433-9. [PMID: 3021392 DOI: 10.1016/0011-2240(86)90028-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
An assay based on comparative investigation of ATPase and ATP synthetase changes in the activity in rat liver mitochondria after low temperature and uncoupler 2,4-dinitrophenol treatment is considered. By varying the activity of the respiratory chain, three extents of membrane cryoinjury could be distinguished by monitoring the changes in ATPase activity under different types of cryoinfluence. The first extent corresponds to a minimum membrane destruction, where the action of the respiratory chain compensates the changes in proton permeability and the cryotreatment does not change the ATPase activity. The second extent corresponds to changes in ion permeability which is partially compensated by the respiratory chain action. The third extent corresponds to a maximum membrane destruction and, therefore, maximum increase in permeability which is related to the irreversible stimulation of the ATPase activity and complete inhibition of the phosphorylation. In this study the extent of cryoinjury in mitochondrial preparations frozen and thawed at different rates was evaluated using this method.
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Tsvetkov T, Tsonev L, Meranzov N, Minkov I. Preservation of integrity of the inner mitochondrial membrane after freeze-thawing and freeze-drying. Cryobiology 1985; 22:301-6. [PMID: 3996019 DOI: 10.1016/0011-2240(85)90177-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The results of this paper illustrate that trehalose partially preserves inner mitochondrial membrane integrity after freeze-thawing and freeze-drying with subsequent rehydration in water. The 2,4-dinitrophenol stimulation of ATPase activity was used as a criterion for membrane integrity. The results show that ATPase activity of lyophilized-rehydrated mitochondria was stimulated up to two to three times.
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Tsvetkov T, Tsonev L, Meranzov N, Minkov I. Functional changes in mitochondrial properties as a result of their membrane cryodestruction. II. Influence of freezing and thawing on ATP complex activity of intact liver mitochondria. Cryobiology 1985; 22:111-8. [PMID: 2983935 DOI: 10.1016/0011-2240(85)90165-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The influence of the freeze-thawing rates on ATP synthetase (ATPase) complex of intact liver mitochondria was investigated. It was shown that the increase in latent ATPase activity and decrease in ATP synthetase activity resulted from an influence on the inner mitochondrial membrane. An increase in freeze-thawing rates led to the preservation of ATP synthetase activity and ATP hydrolysis reduction. Kinetic parameter changes of the ATP synthetase reaction resulted from an insignificant nonspecific increase in the inner mitochondrial membrane permeability and changes in its electrochemical potential level.
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Tsvetkov T, Tsonev L, Meranzov N, Minkov I. Functional changes in mitochondrial properties as a result of their membrane cryodestruction. I. Influence of freezing and thawing on succinate-ferricyanide reductase of intact liver mitochondria. Cryobiology 1985; 22:47-54. [PMID: 3979077 DOI: 10.1016/0011-2240(85)90007-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The interaction of the succinate dehydrogenase complex of rat liver mitochondria with an artificial electron acceptor (K3Fe(CN)6), impermeable to the mitochondrial membrane as an index of a cryoinjury is investigated. It is shown that the freeze-thawing stimulates succinate-ferricyanide reductase (SFCR) activity of intact mitochondria. The increase of the freezing and thawing rates leads to a decrease in the released SFCR activity. The released SFCR activity after low-temperature treatment is a consequence of a nonspecific change in membrane ferricyanide permeability. The released SFCR activity decreases as the freezing and thawing rates increase.
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