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Nishi K, Fujii K, Chung UI, Shibayama M, Sakai T. Experimental Observation of Two Features Unexpected from the Classical Theories of Rubber Elasticity. PHYSICAL REVIEW LETTERS 2017; 119:267801. [PMID: 29328714 DOI: 10.1103/physrevlett.119.267801] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Indexed: 06/07/2023]
Abstract
Although the elastic modulus of a Gaussian chain network is thought to be successfully described by classical theories of rubber elasticity, such as the affine and phantom models, verification experiments are largely lacking owing to difficulties in precisely controlling of the network structure. We prepared well-defined model polymer networks experimentally, and measured the elastic modulus G for a broad range of polymer concentrations and connectivity probabilities, p. In our experiment, we observed two features that were distinct from those predicted by classical theories. First, we observed the critical behavior G∼|p-p_{c}|^{1.95} near the sol-gel transition. This scaling law is different from the prediction of classical theories, but can be explained by analogy between the electric conductivity of resistor networks and the elasticity of polymer networks. Here, p_{c} is the sol-gel transition point. Furthermore, we found that the experimental G-p relations in the region above C^{*} did not follow the affine or phantom theories. Instead, all the G/G_{0}-p curves fell onto a single master curve when G was normalized by the elastic modulus at p=1, G_{0}. We show that the effective medium approximation for Gaussian chain networks explains this master curve.
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Affiliation(s)
- Kengo Nishi
- Department of Bioengineering, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
- Third Institute of Physics-Biophysics, Georg August University, 37077 Goettingen, Germany
| | - Kenta Fujii
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, 2-16-1 Tokiwadai, Ube, Yamaguchi 755-8611, Japan
| | - Ung-Il Chung
- Department of Bioengineering, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Mitsuhiro Shibayama
- Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Takamasa Sakai
- Department of Bioengineering, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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Wolhuter K, Eaton P. How widespread is stable protein S-nitrosylation as an end-effector of protein regulation? Free Radic Biol Med 2017; 109:156-166. [PMID: 28189849 DOI: 10.1016/j.freeradbiomed.2017.02.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 01/26/2017] [Accepted: 02/05/2017] [Indexed: 12/13/2022]
Abstract
Over the last 25 years protein S-nitrosylation, also known more correctly as S-nitrosation, has been progressively implicated in virtually every nitric oxide-regulated process within the cardiovascular system. The current, widely-held paradigm is that S-nitrosylation plays an equivalent role as phosphorylation, providing a stable and controllable post-translational modification that directly regulates end-effector target proteins to elicit biological responses. However, this concept largely ignores the intrinsic instability of the nitrosothiol bond, which rapidly reacts with typically abundant thiol-containing molecules to generate more stable disulfide bonds. These protein disulfides, formed via a nitrosothiol intermediate redox state, are rationally anticipated to be the predominant end-effector modification that mediates functional alterations when cells encounter nitrosative stimuli. In this review we present evidence and explain our reasoning for arriving at this conclusion that may be controversial to some researchers in the field.
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Affiliation(s)
- Kathryn Wolhuter
- King's College London, Cardiovascular Division, The British Heart Foundation Centre of Excellence, The Rayne Institute, St Thomas' Hospital, London SE1 7EH, UK
| | - Philip Eaton
- King's College London, Cardiovascular Division, The British Heart Foundation Centre of Excellence, The Rayne Institute, St Thomas' Hospital, London SE1 7EH, UK.
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Roy A, Sahoo R, Ray C, Dutta S, Pal T. Soft template induced phase selective synthesis of Fe2O3 nanomagnets: one step towards peroxidase-mimic activity allowing colorimetric sensing of thioglycolic acid. RSC Adv 2016. [DOI: 10.1039/c6ra00963h] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The peroxidase-mimicking property of the soft template mediated phase selective α- and γ-Fe2O3 magnetic nanoparticles allows colorimetric sensing for thioglycolic acid down to μM level.
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Affiliation(s)
- Anindita Roy
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
| | - Ramkrishna Sahoo
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
| | - Chaiti Ray
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
| | - Soumen Dutta
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
| | - Tarasankar Pal
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
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Holden MS, Black J, Lewis A, Boutrin MC, Walemba E, Sabir TS, Boskovic DS, Wilson A, Fletcher HM, Perry CC. Antibacterial Activity of Partially Oxidized Ag/Au Nanoparticles against the Oral Pathogen Porphyromonas gingivalis W83. JOURNAL OF NANOMATERIALS 2016; 2016:9605906. [PMID: 30245705 PMCID: PMC6146971 DOI: 10.1155/2016/9605906] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Advances in nanotechnology provide opportunities for the prevention and treatment of periodontal disease. While physicochemical properties of Ag containing nanoparticles (NPs) are known to influence the magnitude of their toxicity, it is thought that nanosilver can be made less toxic to eukaryotes by passivation of the NPs with a benign metal. Moreover, the addition of other noble metals to silver nanoparticles, in the alloy formulation, is known to alter the silver dissolution behavior. Thus, we synthesized glutathione capped Ag/Au alloy bimetallic nanoparticles (NPs) via the galvanic replacement reaction between maltose coated Ag NPs and chloroauric acid (HAuCl4) in 5% aqueous triblock F127 copolymer solution. We then compared the antibacterial activity of the Ag/Au NPs to pure Ag NPs on Porphyromonas gingivalis W83, a key pathogen in the development of periodontal disease. Only partially oxidized glutathione capped Ag and Ag/Au (Au:Ag≈0.2) NPs inhibited the planktonic growth of P. gingivalis W83. This effect was enhanced in the presence of hydrogen peroxide, which simulates the oxidative stress environment in the periodontal pocket during chronic inflammation.
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Affiliation(s)
- Megan S. Holden
- Division of Biochemistry, Loma Linda University School of
Medicine, Loma Linda, CA 92350, USA
| | - Jason Black
- Northern Caribbean University, Manchester, Jamaica
| | | | - Marie-Claire Boutrin
- Division of Microbiology and Molecular Genetics, Loma Linda
University School of Medicine, Loma Linda, CA 92350, USA
| | - Elvin Walemba
- Department of Earth and Biological Sciences, Loma Linda
University School of Medicine, Loma Linda, CA 92350, USA
| | - Theodore S. Sabir
- College of Arts and Sciences, Faulkner University,
Montgomery, AL 36109, USA
| | - Danilo S. Boskovic
- Division of Biochemistry, Loma Linda University School of
Medicine, Loma Linda, CA 92350, USA
- Department of Earth and Biological Sciences, Loma Linda
University School of Medicine, Loma Linda, CA 92350, USA
| | - Aruni Wilson
- Division of Microbiology and Molecular Genetics, Loma Linda
University School of Medicine, Loma Linda, CA 92350, USA
| | - Hansel M. Fletcher
- Division of Microbiology and Molecular Genetics, Loma Linda
University School of Medicine, Loma Linda, CA 92350, USA
| | - Christopher C. Perry
- Division of Biochemistry, Loma Linda University School of
Medicine, Loma Linda, CA 92350, USA
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Catalá-Icardo M, Meseguer-Lloret S, Torres-Cartas S. Photoinduced chemiluminescence determination of carbamate pesticides. Photochem Photobiol Sci 2016; 15:626-34. [DOI: 10.1039/c6pp00056h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Selective and sensitive HPLC-photoinduced chemiluminescence detection of carbamate pesticides containing sulphur in surface and ground water samples.
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Affiliation(s)
- M. Catalá-Icardo
- Instituto de Investigación para la Gestión Integrada de Zonas Costeras. Universitat Politècnica de València
- 46730 Grao de Gandía
- Spain
| | - S. Meseguer-Lloret
- Instituto de Investigación para la Gestión Integrada de Zonas Costeras. Universitat Politècnica de València
- 46730 Grao de Gandía
- Spain
| | - S. Torres-Cartas
- Instituto de Investigación para la Gestión Integrada de Zonas Costeras. Universitat Politècnica de València
- 46730 Grao de Gandía
- Spain
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Martin F, Cayot N, Marin A, Journaux L, Cayot P, Gervais P, Cachon R. Effect of oxidoreduction potential and of gas bubbling on rheological properties and microstructure of acid skim milk gels acidified with glucono-δ-lactone. J Dairy Sci 2009; 92:5898-906. [DOI: 10.3168/jds.2009-2491] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Reipa V. Direct spectroelectrochemical titration of glutathione. Bioelectrochemistry 2004; 65:47-9. [PMID: 15522692 DOI: 10.1016/j.bioelechem.2004.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2004] [Revised: 06/16/2004] [Accepted: 07/02/2004] [Indexed: 11/26/2022]
Abstract
Previous potentiometric attempts to determine the formal potential (E'(0)) of key intracellular redox buffer glutathione resulted in contradictory values. We have developed a spectroelectrochemical method using direct reduction on metal oxide electrodes. Disulfide absorbance at 258 nm was used to titrate glutathione in the thin layer cell reversibly. At conditions close to physiological ([GSH] = 0.001-0.005 mol/l, pH = 7.34; I = 0.1 mol/l; T = 298.15 K), we have measured glutathione E(0)' = -0.22 +/- 0.02 V (NHE), corroborating the results of equilibrium measurements.
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Affiliation(s)
- Vytas Reipa
- Biotechnology Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899-8312, USA.
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Gorin G, Esfandi A, Guthrie GB. Glutathione: Its reaction with NADP and its oxidationredutionpotenial. Arch Biochem Biophys 1975; 168:450-4. [PMID: 237482 DOI: 10.1016/0003-9861(75)90274-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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10
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Weitzman PD. The standard reduction potential and free energy change of disulphide bonds in proteins. BIOCHIMICA ET BIOPHYSICA ACTA 1965; 107:146-8. [PMID: 5857356 DOI: 10.1016/0304-4165(65)90404-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Oxidation-reduction potentials of the system thiourea-formamidine disulfide in some mixed solvents. Russ Chem Bull 1965. [DOI: 10.1007/bf00847898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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HORWITZ L. Observations on the affect of metallic mercury upon some microorganisms. JOURNAL OF CELLULAR AND COMPARATIVE PHYSIOLOGY 1957; 49:437-53. [PMID: 13481077 DOI: 10.1002/jcp.1030490305] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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CHINARD FP, HELLERMAN L. Determination of sulfhydryl groups in certain biological substances. METHODS OF BIOCHEMICAL ANALYSIS 1954; 1:1-26. [PMID: 13193523 DOI: 10.1002/9780470110171.ch1] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
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