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Dong Y, Chen S, Liu TL, Li J. Materials and Interface Designs of Waterproof Field-Effect Transistor Arrays for Detection of Neurological Biomarkers. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2106866. [PMID: 35023615 PMCID: PMC8930526 DOI: 10.1002/smll.202106866] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/05/2021] [Indexed: 06/14/2023]
Abstract
The continuous, real-time, and concurrent detection of multiple biomarkers in bodily fluids is of high significance for advanced healthcare. While active, semiconductor-based biochemical sensing platforms provide levels of functionality exceeding those of their conventional passive counterparts, the stability of the active biosensors in the liquid environment for continuous operation remains a challenging topic. This work reports the development of a class of flexible and waterproof field-effect transistor arrays for multiplexed biochemical sensing. In this design, monolithic, ultrathin, dense, and low defect nanomembranes consisting of monocrystalline Si and thermally grown SiO2 simultaneously serve as high-performance backplane electronics for signal transduction and stable biofluid barriers with high structural integrity due to the high formation temperature. Coupling the waterproof transistors with various ion-selective membranes through the gate electrode allows for sensitive and selective detection of multiple ions as biomarkers for traumatic brain injury. The study also demonstrates a similar encapsulation structure which enables the design of waterproof amperometric sensors based on this materials strategy and integration scheme. Overall, key advantages in flexibility, stability, and multifunctionality highlight the potential of using such electronic sensing platforms for concurrent, continuous detection of various neurological biomarkers, proving a promising approach for early diagnosis and intervention of chronic diseases.
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Affiliation(s)
- Yan Dong
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Shulin Chen
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Tzu-Li Liu
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Jinghua Li
- Department of Materials Science and Engineering, Chronic Brain Injury Program, The Ohio State University, Columbus, OH, 43210, USA
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Deigin VI, Vinogradova JE, Vinogradov DL, Krasilshchikova MS, Ivanov VT. Thymodepressin-Unforeseen Immunosuppressor. Molecules 2021; 26:molecules26216550. [PMID: 34770959 PMCID: PMC8588242 DOI: 10.3390/molecules26216550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/27/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022] Open
Abstract
The paper summarizes the available information concerning the biological properties and biomedical applications of Thymodepressin. This synthetic peptide drug displays pronounced immunoinhibitory activity across a wide range of conditions in vitro and in vivo. The history of its unforeseen discovery is briefly reviewed, and the current as well as potential expansion areas of medicinal practice are outlined. Additional experimental evidence is obtained, demonstrating several potential advantages of Thymodepressin over another actively used immunosuppressor drug, cyclosporin A.
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Affiliation(s)
- Vladislav I Deigin
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya st., 16/10, 117997 Moscow, Russia
| | - Julia E Vinogradova
- Hematology Department, Sechenov First Moscow State Medical University, Russian MOH, Moscow 8-2 Trubetskaya str., 119991 Moscow, Russia
| | - Dmitry L Vinogradov
- Hematology Department, Sechenov First Moscow State Medical University, Russian MOH, Moscow 8-2 Trubetskaya str., 119991 Moscow, Russia
| | - Marina S Krasilshchikova
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya st., 16/10, 117997 Moscow, Russia
| | - Vadim T Ivanov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya st., 16/10, 117997 Moscow, Russia
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The Nonribosomal Peptide Valinomycin: From Discovery to Bioactivity and Biosynthesis. Microorganisms 2021; 9:microorganisms9040780. [PMID: 33917912 PMCID: PMC8068249 DOI: 10.3390/microorganisms9040780] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/03/2021] [Accepted: 04/07/2021] [Indexed: 12/17/2022] Open
Abstract
Valinomycin is a nonribosomal peptide that was discovered from Streptomyces in 1955. Over the past more than six decades, it has received continuous attention due to its special chemical structure and broad biological activities. Although many research papers have been published on valinomycin, there has not yet been a comprehensive review that summarizes the diverse studies ranging from structural characterization, biogenesis, and bioactivity to the identification of biosynthetic gene clusters and heterologous biosynthesis. In this review, we aim to provide an overview of valinomycin to address this gap, covering from 1955 to 2020. First, we introduce the chemical structure of valinomycin together with its chemical properties. Then, we summarize the broad spectrum of bioactivities of valinomycin. Finally, we describe the valinomycin biosynthetic gene cluster and reconstituted biosynthesis of valinomycin. With that, we discuss possible opportunities for the future research and development of valinomycin.
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Lameiras P, Nuzillard JM. Tailoring the nuclear Overhauser effect for the study of small and medium-sized molecules by solvent viscosity manipulation. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2021; 123:1-50. [PMID: 34078536 DOI: 10.1016/j.pnmrs.2020.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 11/06/2020] [Accepted: 12/02/2020] [Indexed: 06/12/2023]
Abstract
The nuclear Overhauser effect (NOE) is a consequence of cross-relaxation between nuclear spins mediated by dipolar coupling. Its sensitivity to internuclear distances has made it an increasingly important tool for the determination of through-space atom proximity relationships within molecules of sizes ranging from the smallest systems to large biopolymers. With the support of sophisticated FT-NMR techniques, the NOE plays an essential role in structure elucidation, conformational and dynamic investigations in liquid-state NMR. The efficiency of magnetization transfer by the NOE depends on the molecular rotational correlation time, whose value depends on solution viscosity. The magnitude of the NOE between 1H nuclei varies from +50% when molecular tumbling is fast to -100% when it is slow, the latter case corresponding to the spin diffusion limit. In an intermediate tumbling regime, the NOE may be vanishingly small. Increasing the viscosity of the solution increases the motional correlation time, and as a result, otherwise unobservable NOEs may be revealed and brought close to the spin diffusion limit. The goal of this review is to report the resolution of structural problems that benefited from the manipulation of the negative NOE by means of viscous solvents, including examples of molecular structure determination, conformation elucidation and mixture analysis (the ViscY method).
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Affiliation(s)
- Pedro Lameiras
- Université de Reims Champagne-Ardenne, CNRS, ICMR UMR 7312, 51097 Reims, France
| | - Jean-Marc Nuzillard
- Université de Reims Champagne-Ardenne, CNRS, ICMR UMR 7312, 51097 Reims, France
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Deigin V, Ksenofontova O, Yatskin O, Goryacheva A, Ignatova A, Feofanov A, Ivanov V. Novel platform for the preparation of synthetic orally active peptidomimetics with hemoregulating activity. II. Hemosuppressor activity of 2,5-diketopiperazine-based cyclopeptides. Int Immunopharmacol 2020; 81:106185. [PMID: 32058926 DOI: 10.1016/j.intimp.2020.106185] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 12/30/2019] [Accepted: 01/01/2020] [Indexed: 12/17/2022]
Abstract
The novel chemical platform formed by the branched piperazine-2,5-dione peptide derivatives (2,5-diketopiperazines) for creating non-invasive biologically active peptidomimetics has been developed. A successful application of this approach to orally available hemostimulatory peptidomimetics was demonstrated for all-L cyclopeptide from the Glu-Trp-peptide family. In the 1980s, we have separated and characterized a number of dipeptides from the thymus homogenate. The most active peptide Glu-Trp has been studied and developed into the immunostimulating drug Thymogen. The inversion of the amino acid optical form endows the dipeptides with suppressor properties: D-Glu-D-Trp-OH and D-Glu-(D-Trp)-OH, inhibit proliferation of hemopoietic progenitors in the intact bone marrow. Based on the peptide D-Glu-(D-Trp)-OH, the new immunosuppressive drug Thymodepressin has been prepared. In this work, we applied the platform mentioned above to the design and synthesis of orally active hemosuppressive Thymodepressin® analogs. The novel data for the hemosuppressor activity of the dipeptide D-Glu(D-Trp-OH)-OH and its cyclopeptide analogs are discussed. A new example is presented of a rare phenomenon when enantiomeric molecules demonstrate reciprocal (i.e., opposite) biological activities.
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Affiliation(s)
- Vladislav Deigin
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia.
| | - Olga Ksenofontova
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Oleg Yatskin
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Alexandra Goryacheva
- Tsyb Medical Radiological Research Center Ministry of Health of Russia, 249030, Kaluga Region, Obninsk, Russia
| | - Anastasia Ignatova
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia; Biological Faculty, Lomonosov Moscow State University, Vorobyevi Gori 1, Moscow 119992, Russia
| | - Alexey Feofanov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia; Biological Faculty, Lomonosov Moscow State University, Vorobyevi Gori 1, Moscow 119992, Russia
| | - Vadim Ivanov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
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Enniatin A1, A Natural Compound with Bactericidal Activity against Mycobacterium tuberculosis In Vitro. Molecules 2019; 25:molecules25010038. [PMID: 31861925 PMCID: PMC6982829 DOI: 10.3390/molecules25010038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 12/12/2022] Open
Abstract
Background: Tuberculosis remains a global disease that poses a serious threat to human health, but there is lack of new and available anti-tuberculosis agents to prevent the emergence of drug-resistant strains. To address this problem natural products are still potential sources for the development of novel drugs. Methods: A whole-cell screening approach was utilized to obtain a natural compound enniatin A1 from a natural products library. The target compound’s antibacterial activity against Mycobacterium tuberculosis (M. tuberculosis) was evaluated by using the resazurin reduction micro-plate assay (REMA) method. The cytotoxicity of the compound against Vero cells was measured to calculate the selectivity index. The intracellular inhibition activity of enniatin A1 was determined. We performed its time-kill kinetic assay against M. tuberculosis. We first tested its synergistic effect in combination with the first and second-line anti-tuberculosis drugs. Finally, we measured the membrane potential and intracellular ATP levels of M. tuberculosis after exposure to enniatin A1. Results: We identified enniatinA1 as a potential antibacterial agent against M. tuberculosis, against which it showed strong selectivity. Enniatin A1 exhibited a time-concentration-dependent bactericidal effect against M. tuberculosis, and it displayed synergy with rifamycin, amikacin, and ethambutol. After exposure to enniatinA1, the membrane potential and intracellular ATP levels of M. tuberculosis was significantly decreased. Conclusions: Enniatin A1 exhibits the positive potential anti-tuberculosis agent characteristics.
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D'Amato A, Volpe R, Vaccaro MC, Terracciano S, Bruno I, Tosolini M, Tedesco C, Pierri G, Tecilla P, Costabile C, Della Sala G, Izzo I, De Riccardis F. Cyclic Peptoids as Mycotoxin Mimics: An Exploration of Their Structural and Biological Properties. J Org Chem 2017; 82:8848-8863. [PMID: 28763612 DOI: 10.1021/acs.joc.7b00965] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyclic peptoids have recently emerged as important examples of peptidomimetics for their interesting complexing properties and innate ability to permeate biological barriers. In the present contribution, experimental and theoretical data evidence the intricate conformational and stereochemical properties of five novel hexameric peptoids decorated with N-isopropyl, N-isobutyl, and N-benzyl substituents. Complexation studies by NMR, in the presence of sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaTFPB), theoretical calculations, and single-crystal X-ray analyses indicate that the conformationally stable host/guest metal adducts display architectural ordering comparable to that of the enniatins and beauvericin mycotoxins. Similarly to the natural depsipeptides, the synthetic oligolactam analogues show a correlation between ion transport abilities in artificial liposomes and cytotoxic activity on human cancer cell lines. The reported results demonstrate that the versatile cyclic peptoid scaffold, for its remarkable conformational and complexing properties, can morphologically mimic related natural products and elicit powerful biological activities.
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Affiliation(s)
| | | | | | | | | | - Massimo Tosolini
- Department of Chemical and Pharmaceutical Sciences, University of Trieste , Via Giorgieri, 1, Trieste 34127, Italy
| | | | | | - Paolo Tecilla
- Department of Chemical and Pharmaceutical Sciences, University of Trieste , Via Giorgieri, 1, Trieste 34127, Italy
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Contractor AA, Kazerouni AM, Michmerhuizen AR, Falkenberry ML, Segovia R, Blair NM, Kim S, Vander Griend DA, Bacsa J, Khan FA, Fujita M. The crystal structure of a valinomycin•2Ca2+ complex and the multi-step solution equilibria in acetonitrile characterised by 1H NMR, UV–Vis, and mass spectrometry. Supramol Chem 2016. [DOI: 10.1080/10610278.2016.1186276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
| | - Amaan M. Kazerouni
- Department of Chemistry, University of West Georgia, Carrollton, GA, USA
| | | | | | - Rigoberto Segovia
- Department of Chemistry, University of West Georgia, Carrollton, GA, USA
| | - Nicholas M. Blair
- Department of Chemistry, University of West Georgia, Carrollton, GA, USA
| | - SeongEun Kim
- Department of Chemistry and Biochemistry, Calvin College, Grand Rapids, MI, USA
| | | | - John Bacsa
- X-ray Crystallography Center, Emory University, Atlanta, GA, USA
| | - Farooq A. Khan
- Department of Chemistry, University of West Georgia, Carrollton, GA, USA
| | - Megumi Fujita
- Department of Chemistry, University of West Georgia, Carrollton, GA, USA
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10
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Goodman M, Gilon C, Kirshenbaum GS, Knobler Y. Polydepsipeptides I. Synthesis and Characterization of Copolymers of α-Amino and α-Hydroxy Acids. Isr J Chem 2013. [DOI: 10.1002/ijch.197200087] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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11
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Stark G, Benz R. The transport of potassium through lipid bilayer membranes by the neutral carriers valinomycin and monactin : Experimental studies to a previously proposed model. J Membr Biol 2013; 5:133-53. [PMID: 24173097 DOI: 10.1007/bf02107720] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/1970] [Indexed: 10/25/2022]
Abstract
Stationary conductance experiments on neutral and negatively charged bilayer membranes in the presence of valinomycin or monactin agree with a recently proposed carrier transport model, which is common to both carrier types. This model assumes an interface reaction between a cation from the aqueous solution and a carrier molecule from the membrane phase to establish charge transport across the interface. The transport across the membrane interior is described by some kind of "Eyring model". The discussion of the current-voltage characteristic, the dependence of membrane conductance on the carrier and K(+) concentrations, and the comparison with appropriate experiments allow correlation of the different rate constants of the transport model. The results show that the rate constants partly depend on the surface charge of the membranes. This dependency can be described by introducing the Gouy-Chapman theory for charged surfaces into the transport model.It was found that the carrier molecules could be added either to the aqueous phase or to the membrane-forming solution. The quantitative treatment of this phenomenon gives an evaluation of the partition coefficient of the carrier molecules between the membrane bulk phase and water.
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Affiliation(s)
- G Stark
- Fachbereich Biologie, Universität Konstanz, D-7750, Konstanz, Germany
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12
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Synergistic effect of a novel cyclic pentadepsipeptide, neoN-methylsansalvamide, and paclitaxel on human multidrug resistance cancer cell lines. Anticancer Drugs 2013; 24:455-60. [PMID: 23411682 DOI: 10.1097/cad.0b013e32835f060d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
NeoN-methylsansalvamide is a novel low-molecular-weight cyclic pentadepsipeptide that exerts cytotoxic effects on various human cancer cell lines. Its structural analysis using liquid chromatography mass/mass spectrometry showed the cyclic structure sequence -phenylalanine-leucine-valine-N-methylleucine-leucic acid-. The intrinsic cytotoxic and multidrug resistance reversal effects of neoN-methylsansalvamide were evaluated on the human cancer cell lines MES-SA and HCT15 as well as on their multidrug resistance sublines (MES-SA/DX5 and HCT15/CL05, respectively) using the sulforhodamine B assay. The EC50 values of paclitaxel for MES-SA, HCT15, and for the multidrug resistance sublines MES-SA/DX5 and HCT15/CL05 were 1.00±0.20, 0.85±0.63, 10.00±0.53, and >1000 nmol/l, respectively. However, the EC50 values for paclitaxel including 3 μmol/l neoN-methylsansalvamide for MES-SA/DX5, HCT15, and HCT15/CL02 were 1.58±0.12, 0.10±0.02, and 288.40±21.02 nmol/l, respectively. The in-vitro multidrug resistance reversal activity of neoN-methylsansalvamide was similar to that of the control verapamil. These finding suggests that a novel cyclic pentadepsipeptide, neoN-methylsansalvamide, is effective in reversing multidrug resistance in vitro, and this activity may be a major applicable biological function of this compound.
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Makrlík E, Vaňura P, Selucký P. Complexation of valinomycin with some univalent organic cations in nitrobenzene saturated with water. J Mol Liq 2013. [DOI: 10.1016/j.molliq.2012.10.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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14
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Sy-Cordero AA, Pearce CJ, Oberlies NH. Revisiting the enniatins: a review of their isolation, biosynthesis, structure determination and biological activities. J Antibiot (Tokyo) 2012; 65:541-9. [PMID: 22990381 PMCID: PMC3573854 DOI: 10.1038/ja.2012.71] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Enniatins are cyclohexadepsipeptides isolated largely from Fusarium species of fungi, although they have been isolated from other genera, such as Verticillium and Halosarpheia. They were first described over 60 years ago, and their range of biological activities, including antiinsectan, antifungal, antibiotic and cytotoxic, drives contemporary interest. To date, 29 enniatins have been isolated and characterized, either as a single compound or mixtures of inseparable homologs. Structurally, these depsipeptides are biosynthesized by a multifunctional enzyme, termed enniatin synthetase, and are composed of six residues that alternate between N-methyl amino acids and hydroxy acids. Their structure elucidation can be challenging, particularly for enniatins isolated as inseparable homologs; however, several strategies and tools have been utilized to solve these problems. Currently, there is one drug that has been developed from a mixture of enniatins, fusafungine, which is used as a topical treatment of upper respiratory tract infections by oral and/or nasal inhalation. Given the range of biological activities observed for this class of compounds, research on enniatins will likely continue. This review strives to digest the past studies, as well as, describe tools and techniques that can be utilized to overcome the challenges associated with the structure elucidation of mixtures of enniatin homologs.
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Affiliation(s)
- Arlene A Sy-Cordero
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
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Halsey CM, Benham DA, JiJi RD, Cooley JW. Influence of the lipid environment on valinomycin structure and cation complex formation. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 96:200-206. [PMID: 22683555 DOI: 10.1016/j.saa.2012.05.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 05/01/2012] [Accepted: 05/07/2012] [Indexed: 06/01/2023]
Abstract
Carrier-type molecular ionophores, such as the cyclic dodecadepsipeptide valinomycin, often must undergo structural changes during the binding and transport of a cation across the lipid membrane. Observing the structural fluctuations that occur during this process experimentally has proven extremely difficult due to the complexities of spectroscopic analysis of protein structure/dynamics in native lipid bilayer environments. Currently, our understanding of how valinomycin selectively transports ions across membranes is derived from atomic structures solved of the cyclic macromolecule solvated in various organic solvents and complimentary in silico dynamics experiments. We have shown recently that deep-UV excited resonance Raman spectroscopy (DUVRR) has a unique ability to characterize secondary structure content and simultaneously provide information about the relative solvation of the probed peptide backbone C.M. Halsey, J. Xiong, O. Oshokoya, J.A. Johnson, S. Shinde, J.T. Beatty, G. Ghirlanda, R.D. JiJi, J.W. Cooley, Simultaneous observation of peptide backbone lipid solvation and a-helical structure by deep-UV resonance Raman spectroscopy, ChemBioChem 12 (2011) 2125-2128, [16]. Interpretation of DUVRR spectra of valinomycin in swelled lipid and unilamellar lipid bilayer environments indicate that the uncomplexed valinomycin molecule dynamically samples both the open and closed conformations as described for the structures derived from polar and non-polar organic solvents, respectively. Upon introduction of potassium, the structure of valinomycin in swelled lipid environments resembles more closely that of the open conformation. The shift in structure upon complexation is accompanied by a significant decrease in the valinomycin DUVRR spectral amide I intensity, indicating that the open conformation is more water solubilized and is seemingly "trapped" or predominantly located close to the lipid-water interface. The trapping of the valinomycin in the act of complex of potassium at the bilayer-solvent interface and its analysis by DUVRR represents the first spectroscopic description of this state. Conversely, an opposite trend is observed in the amide I intensity upon potassium complexation in unilamellar (or extruded) vesicles, implying the predominant conformation upon potassium binding in native bilayers is one where the peptide backbone of valinomycin is desolvated as would be expected if the molecule were more readily able to traverse a bilayer interior. Interpretation of the DUVRR spectral features is also consistent with the loss or formation of hydrogen bonds observed in the open and closed structures, respectively. Valinomycin must then sample several conformations in the absence of appropriate ions depending upon its locale in the lipid bilayer until potassium causes a greater degree of closure of the open conformer and an increased residency within the more non-polar interior. The potassium induced decreased solubility enables diffusion across the membrane where potassium release can occur by equilibration at the opposite lipid water interface.
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16
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Lee HS, Lee C. Structural analysis of a new cytotoxic demethylated analogue of neo-N-methylsansalvamide with a different peptide sequence produced by Fusarium solani isolated from potato. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:4342-4347. [PMID: 22502643 DOI: 10.1021/jf205217v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A novel cytotoxic cyclic pentadepsipeptide, neosansalvamide, was produced by Fusarium solani KCCM90040 isolated from Fusarium -contaminated potato in Korea. The molecular formula of neosansalvamide was analyzed as C₃₂H₅₀N₄O₆ by electrospray ionization tandem mass spectrometry and combined structural analysis. The one- and two-dimensional nuclear magnetic resonance and absolute configuration of amino acid spectral data allowed for the resolution of cyclic five subunits linked in the following order: (S)-leucic acid, two L-leucine, L-valine, and L-phenylalanine, and this sequence shows a molecular structure as a new demethylated analogue of neo-N-methylsansalvamide but having a different peptide sequence. The cytotoxic effects of neosansalvamide were investigated by sulforhodamine B bioassay on four human cancer cell lines. The IC₅₀ value of neosansalvamide required to inhibit cell growth in vitro by 50% for A549 (lung cancer), SK-OV-3 (ovarian cancer), SK-MEL-2 (skin melanoma), and MES-SA (uterine sarcoma) cell lines were 11.70 ± 0.55, 10.38 ± 0.64, 13.99 ± 1.32, and 11.75 ± 0.13 μM, respectively (mean ± standard error).
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Affiliation(s)
- Hee-Seok Lee
- Department of Food Science and Technology, Chung-Ang University, Anseong 456-756, Republic of Korea
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17
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Conformational analyses of peptides and proteins by vibrational Raman optical activity. Anal Bioanal Chem 2012; 403:2203-12. [DOI: 10.1007/s00216-012-5891-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 02/09/2012] [Accepted: 02/20/2012] [Indexed: 10/28/2022]
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18
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Song HH, Lee HS, Lee C. A new cytotoxic cyclic pentadepsipeptide, neo-N-methylsansalvamide produced by Fusarium solani KCCM90040, isolated from potato. Food Chem 2011. [DOI: 10.1016/j.foodchem.2010.11.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Toxigenicity of enniatins from Western Australian Fusarium species to brine shrimp (Artemia franciscana). Toxicon 2011; 57:817-25. [DOI: 10.1016/j.toxicon.2011.02.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 02/14/2011] [Accepted: 02/15/2011] [Indexed: 11/21/2022]
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20
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Yamamoto S, Watarai H, Bouř P. Monitoring the Backbone Conformation of Valinomycin by Raman Optical Activity. Chemphyschem 2011; 12:1509-18. [DOI: 10.1002/cphc.201000917] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/18/2011] [Indexed: 11/11/2022]
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Howarth VA, Petty MC, Lvov Y. Structure of valinomycin/fatty acid langmuir-blodgett films. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/masy.19910510115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Wang Y, Niu L, Li Y, Mao X, Yang Y, Wang C. Single molecule studies of cyclic peptides using molecular matrix at liquid/solid interface by scanning tunneling microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:16305-16311. [PMID: 20593799 DOI: 10.1021/la101467s] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We report in this work the single molecule studies of cyclic peptide, cyclosporine A (CsA), using a molecular network formed by star-shaped oligofluorene (StOF-COOH(3)) at the liquid/solid interface by scanning tunneling microscopy (STM). Individual cyclosporine A can be identified and resolved in the molecular network, and the high-resolution STM images of CsA show polygon-like characteristics with a diameter of approximately 1.7 nm. Furthermore, the complex of CsA and Mg(2+) has also been observed to adsorb inside of the molecular matrix. The STM results reveal two adsorption characteristics for the CsA-Mg(2+) complex, which is suggestive of asymmetrical configurations of the complex. The difference in binding energy between the two observed adsorption configurations is estimated to be 1.88 kJ·mol(-1). These results help set the stage for studying the fine structures and functions of various cyclic peptides at the liquid/solid interface.
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Affiliation(s)
- Yibing Wang
- National Center for Nanoscience and Technology, Beijing 100190, PR China
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A combined experimental and theoretical study on the complexation of the ammonium cation with valinomycin. MONATSHEFTE FUR CHEMIE 2010. [DOI: 10.1007/s00706-010-0395-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Yamamoto S, Straka M, Watarai H, Bouř P. Formation and structure of the potassium complex of valinomycin in solution studied by Raman optical activity spectroscopy. Phys Chem Chem Phys 2010; 12:11021-32. [DOI: 10.1039/c003277h] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Dybal J, Makrlík E, Vaňura P. Extraction and DFT study on the complexation of Mg2+ with valinomycin. MONATSHEFTE FUR CHEMIE 2009. [DOI: 10.1007/s00706-009-0217-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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26
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Dybal J, Makrlík E, Vanura P. Experimental and DFT Study on the Complexation of Zn2+with Valinomycin. Z PHYS CHEM 2009. [DOI: 10.1524/zpch.2009.5465] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
AbstractFrom extraction experiments andγ-activity measurements, the exchange extraction constant corresponding to the equilibrium Zn2+(aq) +1 ·Sr2+(nb) ⇌1 ·Zn2+(nb) + Sr2+(aq) taking place in the two–phase water–nitrobenzene system (1= valinomycin; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as logKex(Zn2+,1 ·Sr2+) = −0.2±0.1. Further, the stability constant of the valinomycin–zinc complex (abbrev.1 ·Zn2+) in nitrobenzene saturated with water was calculated for a temperature of 25oC: logβnb(1 ·Zn2+) = 6.1±0.1. By using quantum mechanical DFT calculations, the most probable structure of the1 ·Zn2+complex species was predicted. In this complex, the Zn2+cation sits in the center of the coordination cavity formed by six ester carbonyls, which are oriented almost exactly in the “radial directions”. Finally, the calculated binding energy of the resulting complex1 ·Zn2+is −359.5 kcal/mol confirming relatively high stability of the considered cationic complex species.
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A combined extraction and DFT study on the complexation of K+ with valinomycin. MONATSHEFTE FUR CHEMIE 2009. [DOI: 10.1007/s00706-009-0178-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Application of capillary affinity electrophoresis and density functional theory to the investigation of valinomycin–lithium complex. J Chromatogr A 2009; 1216:3660-5. [DOI: 10.1016/j.chroma.2009.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2008] [Revised: 01/29/2009] [Accepted: 02/02/2009] [Indexed: 11/20/2022]
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Ehala S, Dybal J, Makrlík E, Kašička V. Capillary electrophoretic and computational study of the complexation of valinomycin with rubidium cation. Electrophoresis 2009; 30:883-9. [DOI: 10.1002/elps.200800610] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Apoptosis induced by enniatins H and MK1688 isolated from Fusarium oxysporum FB1501. Toxicon 2009; 53:723-8. [PMID: 19248798 DOI: 10.1016/j.toxicon.2009.02.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 02/12/2009] [Accepted: 02/13/2009] [Indexed: 11/20/2022]
Abstract
Enniatins are cyclic peptides isolated from bacteria, fungi, and plants, with numerous biological effects on animal systems. Recently, we have reported that certain enniatins (ENs), such as EN H and EN MK1688, have cytotoxic effects on several adenocarcinoma cell lines. In an effort to understand the mechanism behind their cytotoxicity, we investigated whether ENs can induce apoptosis in human colorectal carcinoma cells (HCT-15 cells). Treatment with the ENs H and MK1688 resulted in an alteration of cellular and nuclear morphology, leading to an increase in the number of the cells with apoptotic nuclei (seen as condensed or fragmented nuclei). Furthermore, it was observed that cellular DNA fragmentation increased in a dose-dependent manner in EN treated cells. These cells have elevated activity levels for caspase-3, the enzyme responsible for initiating cell death, compared with the untreated cells. Normal caspase-3 activity levels were observed when Z-VAD-FMK, a caspase inhibitor, was added simultaneously with the ENs. Based on our results, we propose that the new ENs H and MK1688 induce cytotoxicity via an apoptotic pathway.
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Ehala S, Dybal J, Makrlík E, Kašička V. Capillary affinity electrophoresis andab initiocalculation studies of valinomycin complexation with Na+ion. J Sep Sci 2009; 32:597-604. [DOI: 10.1002/jssc.200800555] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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32
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Ovchinnikov YA, Ivanov VT, Evstratov AV, Mikhaleva II, Bystrov VF, Portnova SL, Balashova TA, Meshcheryakova EN, Tulchinsky VM. The enniatin ionophores. Conformation and ion binding properties. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 2009; 6:465-98. [PMID: 4455641 DOI: 10.1111/j.1399-3011.1974.tb02407.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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33
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A combined experimental and theoretical study on the complexation of Li+ with valinomycin. MONATSHEFTE FUR CHEMIE 2008. [DOI: 10.1007/s00706-008-0003-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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34
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Dybal J, Makrlík E, Vaňura P. Extraction and ab initio calculation studies on the complexation of Ca2+ with valinomycin. J Radioanal Nucl Chem 2008. [DOI: 10.1007/s10967-008-7344-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Dybal J, Ehala S, Kašička V, Makrlík E. Theoretical and experimental study of the complexation of valinomycin with ammonium cation. Biopolymers 2008; 89:1055-60. [DOI: 10.1002/bip.21034] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Lee HS, Song HH, Jeong JH, Shin CG, Choi SU, Lee C. Cytotoxicities of enniatins H, I, and MK1688 from Fusarium oxysporum KFCC 11363P. Toxicon 2008; 51:1178-85. [DOI: 10.1016/j.toxicon.2008.02.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 02/02/2008] [Accepted: 02/05/2008] [Indexed: 10/22/2022]
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Makrlík E, Vaňura P, Selucký P. Experimental evidences for some unusual divalent cation complexes of valinomycin. MONATSHEFTE FUR CHEMIE 2008. [DOI: 10.1007/s00706-007-0816-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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39
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Kinetics and mechanism of alkali ion complex formation in solution. STRUCTURE AND BONDING 2008. [DOI: 10.1007/bfb0119199] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Song HH, Lee HS, Jeong JH, Park HS, Lee C. Diversity in Beauvericin and Enniatins H, I, and MK1688 by Fusarium oxysporum isolated from potato. Int J Food Microbiol 2008; 122:296-301. [DOI: 10.1016/j.ijfoodmicro.2008.01.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Revised: 01/12/2008] [Accepted: 01/15/2008] [Indexed: 10/22/2022]
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41
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Varma S, Sabo D, Rempe SB. K+/Na+ selectivity in K channels and valinomycin: over-coordination versus cavity-size constraints. J Mol Biol 2008; 376:13-22. [PMID: 18155244 PMCID: PMC2390915 DOI: 10.1016/j.jmb.2007.11.059] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Revised: 11/15/2007] [Accepted: 11/19/2007] [Indexed: 11/17/2022]
Abstract
Potassium channels and valinomycin molecules share the exquisite ability to select K(+) over Na(+). Highly selective K channels maintain a special local environment around their binding sites devoid of competing hydrogen bond donor groups, which enables spontaneous transfer of K(+) from states of low coordinations in water into states of over-coordination by eight carbonyl ligands. In such a phase-activated state, electrostatic interactions from these 8-fold binding sites, constrained to maintain high coordinations, result in K(+)/Na(+) selectivity with no need for a specific cavity size. Under such conditions, however, direct coordination from five or six carbonyl ligands does not result in selectivity. Yet, valinomycin molecules achieve selectivity by providing only six carbonyl ligands. Does valinomycin use additional coordinating ligands from the solvent or does it have special structural features not present in K channels? Quantum chemical investigations undertaken here demonstrate that valinomycin selectivity is due to cavity size constraints that physically prevent it from collapsing onto the smaller sodium ion. Valinomycin enforces these constraints by using a combination of intramolecular hydrogen bonds and other structural features, including its specific ring size and the spacing between its connected ligands. Results of these investigations provide a consistent explanation for the experimental data available for the ion-complexation properties of valinomycin in solvents of varying polarity. Together, investigations of these two systems reveal how nature, despite being popular for its parsimony in recycling functional motifs, can use different combinations of phase, coordination number, cavity size, and rigidity (constraints) to achieve K(+)/Na(+) selectivity.
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Affiliation(s)
- Sameer Varma
- Computational Bioscience Department, Sandia National Laboratories, Albuquerque, NM 87185, USA
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Solvent extraction of magnesium, zinc and manganese into nitrobenzene by using strontium dicarbollylcobaltate in the presence of valinomycin. J Radioanal Nucl Chem 2008. [DOI: 10.1007/s10967-007-7022-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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43
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Burgermeister W, Winkler-Oswatitsch R. Complex formation of monovalent cations with biofunctional ligands. Top Curr Chem (Cham) 2007. [DOI: 10.1007/bfb0111222] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Abstract
Valinomycin is shown to form a stable complex with protons in the form of H3O+ ions. Using 1H and 13C nuclear magnetic resonance (NMR), Fourier transform (FT) infrared spectroscopy, and ab initio-density functional theory (DFT) quantum mechanical calculations, it is shown that H3O+, produced by hydrogen bis(1,2-dicarbollyl) cobaltate (HDCC) in the presence of water, interacts with valinomycin in 1,1,2,2-tetrachloroethane-d2 to give a relatively stable complex. The equilibrium constant K of the complex formation was derived from chemical shifts in 1H-NMR, its value being 5.9. The proton affinity constant estimated from this value taking into account HDCC dissociation is 10(5.3), i.e., high enough to be relevant under physiological conditions. Under suitable conditions there is a fast exchange of H3O+ between valinomycin molecules, the exchange correlation time being of the order of 10(-4) s. The instantaneous structure of the complex is slightly asymmetric, the H3O+ ion being strongly hydrogen-bonded to three of the six ester carbonyl groups and weekly bound to the residual ones by electrostatic interactions. This asymmetry is averaged by fast reorientation and displacement of H3O+ so that the molecule appears to be symmetric in the time window of NMR. The results indicate that valinomycin could serve as a carrier for proton transfer across a biological membrane.
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Affiliation(s)
- Jaroslav Kríz
- Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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Abstract
In addition to the well-known complexes of valinomycin with alkali metal cations, an equimolar complex of the same compound with proton was found to be formed in nitrobenzene. Hydrogen bis(1,2-dicarbollylide) cobaltate (HDCC) was used as a proton source. According to NMR spectra, the complex formation is quantitative at proton/valinomycin molar ratios up to 1:1 but there is fast exchange of protons between coordinated and uncoordinated valinomycin molecules at lower ratios. 1H and 13C NMR spectra show a dramatic change in the valinomycin conformation during its coordination with protons, probably from a propeller-like to a bracelet-like form. As valinomycin is one of the well-known ion-carrying ionophores facilitating especially the K+ ion transport across a biological membrane, the existence of the valinomycin-proton complex could be important in biochemistry and biology.
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Affiliation(s)
- Jaroslav Kríz
- Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Ivanova L, Skjerve E, Eriksen GS, Uhlig S. Cytotoxicity of enniatins A, A1, B, B1, B2 and B3 from Fusarium avenaceum. Toxicon 2006; 47:868-76. [PMID: 16730043 DOI: 10.1016/j.toxicon.2006.02.012] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 02/03/2006] [Accepted: 02/07/2006] [Indexed: 10/24/2022]
Abstract
The enniatins A, A1, B, B1, B2 and B3 were purified from hexane-extracts of Fusarium avenaceum rice cultures, using semi-preparative HPLC, after precipitation of lipids. Their toxicity, as well as the toxicity of the related fungal metabolite beauvericin (Bea) and the trichothecenes deoxynivalenol (DON) and T-2 toxin, was tested in two cell lines of human origin (hepatocellular carcinoma-line Hep G2 and fibroblast-like foetal lung cell line MRC-5) by using the BrdU and Alamar Blue assays. All the compounds evoked toxicity in the in vitro assays at the concentrations tested. The MRC-5 cell line in combination with the BrdU assay resulted in the lowest inhibitory concentrations (IC(50)) for exposure with enniatins in the range 0.8 microM (enniatin A) to 3.6 microM (enniatin B). The cytotoxicity of DON in the BrdU assay was comparable to the cytotoxicity of enniatins A, B and Bea in a multiple regression model, while DON was significantly more cytotoxic than the enniatins in the Alamar assay. This study indicates that enniatins, fungal metabolites that are commonly found in grain in Northern Europe, may have an underestimated toxic potential.
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Affiliation(s)
- Lada Ivanova
- National Veterinary Institute, P.O. Box 8156 Dep., N-0033 Oslo, Norway
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Kamyar MR, Kouri K, Rawnduzi P, Studenik C, Lemmens-Gruber R. Effects of moniliformin in presence of cyclohexadepsipeptides on isolated mammalian tissue and cells. Toxicol In Vitro 2006; 20:1284-91. [PMID: 16621435 DOI: 10.1016/j.tiv.2006.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Revised: 02/14/2006] [Accepted: 03/01/2006] [Indexed: 11/22/2022]
Abstract
Secondary metabolites produced by Fusarium spp. including beauvericin, enniatin and moniliformin are mycotoxins identified in cereal samples. The two cyclohexadepsipeptide mycotoxins beauvericin and enniatin have cytotoxic, antibiotic, insecticidal and ionophoric properties, while moniliformin primarily acts as a cardiotoxic mycotoxin. In this study, we examined the electromechanical and electrophysiological effects of moniliformin and moniliformin with ionophoric mycotoxins on cells (ventricular myocytes, Caco-2 cells) and in multicellular preparations (papillary muscles and terminal ilea of the guinea pig). Additionally, we investigated the influence of moniliformin on cell homeostasis in absence and presence of the cyclodepsipeptide mycotoxins (ventricular myocytes, Caco-2 cells). Experiments were performed using isometric measurements of contractility, intracellular microelectrode and patch-clamp techniques, and fluorescence imaging. While ionophoric cyclohexadepsipeptides affect action potential parameters and cell homeostasis, moniliformin did not change spontaneous rates of activity or cardiac action potentials. Furthermore, moniliformin had no effect on intracellular concentrations of ions and ATP, and did not affect pH. Moniliformin reduced contractility in papillary muscle, terminal ileum, the aorta and the pulmonary artery. However, moniliformin did not alter beauvericin and enniatin induced effects. From our studies, we conclude that moniliformin is not solely a cardiotoxic secondary metabolite, but also exerts its effects on smooth muscle. Moreover, there is no synergistic relationship between moniliformin and the concurrently produced cyclohexadepsipeptide mycotoxins beauvericin and enniatin.
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Affiliation(s)
- M R Kamyar
- Department of Pharmacology and Toxicology, University of Vienna, Pharmacy Centre, Althanstrasse 14, A-1090 Vienna, Austria
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