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Jian N, Dowle M, Horniblow RD, Tselepis C, Palmer RE. Morphology of the ferritin iron core by aberration corrected scanning transmission electron microscopy. Nanotechnology 2016; 27:46LT02. [PMID: 27734804 DOI: 10.1088/0957-4484/27/46/46lt02] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
As the major iron storage protein, ferritin stores and releases iron for maintaining the balance of iron in fauna, flora, and bacteria. We present an investigation of the morphology and iron loading of ferritin (from equine spleen) using aberration-corrected high angle annular dark field scanning transmission electron microscopy. Atom counting method, with size selected Au clusters as mass standards, was employed to determine the number of iron atoms in the nanoparticle core of each ferritin protein. Quantitative analysis shows that the nuclearity of iron atoms in the mineral core varies from a few hundred iron atoms to around 5000 atoms. Moreover, a relationship between the iron loading and iron core morphology is established, in which mineral core nucleates from a single nanoparticle, then grows along the protein shell before finally forming either a solid or hollow core structure.
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Affiliation(s)
- Nan Jian
- Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, UK
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Horniblow RD, Dowle M, Iqbal TH, Latunde-Dada GO, Palmer RE, Pikramenou Z, Tselepis C. Alginate-Iron Speciation and Its Effect on In Vitro Cellular Iron Metabolism. PLoS One 2015; 10:e0138240. [PMID: 26378798 PMCID: PMC4574481 DOI: 10.1371/journal.pone.0138240] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 08/27/2015] [Indexed: 11/18/2022] Open
Abstract
Alginates are a class of biopolymers with known iron binding properties which are routinely used in the fabrication of iron-oxide nanoparticles. In addition, alginates have been implicated in influencing human iron absorption. However, the synthesis of iron oxide nanoparticles employs non-physiological pH conditions and whether nanoparticle formation in vivo is responsible for influencing cellular iron metabolism is unclear. Thus the aims of this study were to determine how alginate and iron interact at gastric-comparable pH conditions and how this influences iron metabolism. Employing a range of spectroscopic techniques under physiological conditions alginate-iron complexation was confirmed and, in conjunction with aberration corrected scanning transmission electron microscopy, nanoparticles were observed. The results infer a nucleation-type model of iron binding whereby alginate is templating the condensation of iron-hydroxide complexes to form iron oxide centred nanoparticles. The interaction of alginate and iron at a cellular level was found to decrease cellular iron acquisition by 37% (p < 0.05) and in combination with confocal microscopy the alginate inhibits cellular iron transport through extracellular iron chelation with the resulting complexes not internalised. These results infer alginate as being useful in the chelation of excess iron, especially in the context of inflammatory bowel disease and colorectal cancer where excess unabsorbed luminal iron is thought to be a driver of disease.
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Affiliation(s)
- Richard D. Horniblow
- University of Birmingham, School of Cancer Sciences, College of Medical and Dental Sciences, Vincent Drive, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Miriam Dowle
- University of Birmingham, School of Physics, College of Engineering and Physical Sciences, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Tariq H. Iqbal
- University of Birmingham, School of Cancer Sciences, College of Medical and Dental Sciences, Vincent Drive, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Gladys O. Latunde-Dada
- Diabetes and Nutritional Sciences, King's College London, Franklin Wilkins Building, 150 Stamford Street, London, SE1 9NH, United Kingdom
| | - Richard E. Palmer
- University of Birmingham, School of Physics, College of Engineering and Physical Sciences, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Zoe Pikramenou
- University of Birmingham, School of Chemistry, College of Engineering and Physical Sciences, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Chris Tselepis
- University of Birmingham, School of Cancer Sciences, College of Medical and Dental Sciences, Vincent Drive, Edgbaston, Birmingham, B15 2TT, United Kingdom
- * E-mail:
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Finch H, Pegg NA, McLaren J, Lowdon A, Bolton R, Coote SJ, Dyer U, Montana JG, Owen MR, Dowle M, Buckley D, Ross BC, Campbell C, Dix C, Mooney C, Man-Tang C, Patel C. 5,5-trans lactone-containing inhibitors of serine proteases: identification of a novel, acylating thrombin inhibitor. Bioorg Med Chem Lett 1998; 8:2955-60. [PMID: 9873654 DOI: 10.1016/s0960-894x(98)00531-9] [Citation(s) in RCA: 15] [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: 11/25/2022]
Abstract
Synthesis of a variety of 5,5-trans fused lactones, related to compounds found in extracts of Lantana camara, has provided a series of novel acylating inhibitors of human thrombin, trypsin, chymotrypsin and human leucocyte elastase. The most effective thrombin inhibitor is 7 with an IC50 of 130 nM and a Kobs/[1] of 4,000 M-1 s-1.
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Affiliation(s)
- H Finch
- Department of Medicinal Chemistry, GlaxoWellcome Research and Development, Stevenage, Herts., U.K.
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