Investigation of biophysical characteristics of diabetic living eye tissues using PA-FTIR-spectroscopy

Ayman, A; Talaat, M.S.; Negm, S.; Talaat, H.

doi:10.1140/epjst/e2008-00493-5

Cited by 7 publications

(5 citation statements)

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“…5B). These peaks can be attributed to the presence of serum proteins in bions, in line with earlier studies [75], [84].…”

Section: Resultssupporting

confidence: 90%

Bions: A Family of Biomimetic Mineralo-Organic Complexes Derived from Biological Fluids

Young²,

Young³

et al. 2013

PLoS ONE

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Mineralo-organic nanoparticles form spontaneously in human body fluids when the concentrations of calcium and phosphate ions exceed saturation. We have shown previously that these mineralo-organic nanoparticles possess biomimetic properties and can reproduce the whole phenomenology of the so-called nanobacteria—mineralized entities initially described as the smallest microorganisms on earth. Here, we examine the possibility that various charged elements and ions may form mineral nanoparticles with similar properties in biological fluids. Remarkably, all the elements tested, including sodium, magnesium, aluminum, calcium, manganese, iron, cobalt, nickel, copper, zinc, strontium, and barium form mineralo-organic particles with bacteria-like morphologies and other complex shapes following precipitation with phosphate in body fluids. Upon formation, these mineralo-organic particles, which we term bions, invariably accumulate carbonate apatite during incubation in biological fluids; yet, the particles also incorporate additional elements and thus reflect the ionic milieu in which they form. Bions initially harbor an amorphous mineral phase that gradually converts to crystals in culture. Our results show that serum produces a dual inhibition-seeding effect on bion formation. Using a comprehensive proteomic analysis, we identify a wide range of proteins that bind to these mineral particles during incubation in medium containing serum. The two main binding proteins identified, albumin and fetuin-A, act as both inhibitors and seeders of bions in culture. Notably, bions possess several biomimetic properties, including the possibility to increase in size and number and to be sub-cultured in fresh culture medium. Based on these results, we propose that bions represent biological, mineralo-organic particles that may form in the body under both physiological and pathological homeostasis conditions. These mineralo-organic particles may be part of a physiological cycle that regulates the function, transport and disposal of elements and minerals in the human body.

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“…5B). These peaks can be attributed to the presence of serum proteins in bions, in line with earlier studies [75], [84].…”

Section: Resultssupporting

confidence: 90%

Bions: A Family of Biomimetic Mineralo-Organic Complexes Derived from Biological Fluids

Young²,

Young³

et al. 2013

PLoS ONE

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“…These peaks correspond to the different modes of absorption of the amide bond commonly found in proteins. For instance, the peak of amide I is principally attributed to the stretching vibration of the C = O bond, while the peak of amide II represents the bending of the planar N-H bond as well as the stretching vibration of the C-N bond [51] . Finally, the peak of amide III also corresponds to the bending of the N-H bond [51] .…”

Section: Resultsmentioning

confidence: 99%

“…For instance, the peak of amide I is principally attributed to the stretching vibration of the C = O bond, while the peak of amide II represents the bending of the planar N-H bond as well as the stretching vibration of the C-N bond [51] . Finally, the peak of amide III also corresponds to the bending of the N-H bond [51] . The presence of these different absorption components of the amide bond indicates that proteins are abundantly present in the serum granulations.…”

Section: Resultsmentioning

confidence: 99%

Characterization of Granulations of Calcium and Apatite in Serum as Pleomorphic Mineralo-Protein Complexes and as Precursors of Putative Nanobacteria

et al. 2009

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Calcium and apatite granulations are demonstrated here to form in both human and fetal bovine serum in response to the simple addition of either calcium or phosphate, or a combination of both. These granulations are shown to represent precipitating complexes of protein and hydroxyapatite (HAP) that display marked pleomorphism, appearing as round, laminated particles, spindles, and films. These same complexes can be found in normal untreated serum, albeit at much lower amounts, and appear to result from the progressive binding of serum proteins with apatite until reaching saturation, upon which the mineralo-protein complexes precipitate. Chemically and morphologically, these complexes are virtually identical to the so-called nanobacteria (NB) implicated in numerous diseases and considered unusual for their small size, pleomorphism, and the presence of HAP. Like NB, serum granulations can seed particles upon transfer to serum-free medium, and their main protein constituents include albumin, complement components 3 and 4A, fetuin-A, and apolipoproteins A1 and B100, as well as other calcium and apatite binding proteins found in the serum. However, these serum mineralo-protein complexes are formed from the direct chemical binding of inorganic and organic phases, bypassing the need for any biological processes, including the long cultivation in cell culture conditions deemed necessary for the demonstration of NB. Thus, these serum granulations may result from physiologically inherent processes that become amplified with calcium phosphate loading or when subjected to culturing in medium. They may be viewed as simple mineralo-protein complexes formed from the deployment of calcification-inhibitory pathways used by the body to cope with excess calcium phosphate so as to prevent unwarranted calcification. Rather than representing novel pathophysiological mechanisms or exotic lifeforms, these results indicate that the entities described earlier as NB most likely originate from calcium and apatite binding factors in the serum, presumably calcification inhibitors, that upon saturation, form seeds for HAP deposition and growth. These calcium granulations are similar to those found in organisms throughout nature and may represent the products of more general calcium regulation pathways involved in the control of calcium storage, retrieval, tissue deposition, and disposal.

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“…13A–C ; see refs. [127] , [133] ). However, we also observed that the same peak corresponding to amide I at 1,660 cm −1 might also overlap with a peak corresponding to water that was found at 1,650 cm −1 in the control specimens prepared in the absence of proteins ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Fetuin-A/Albumin-Mineral Complexes Resembling Serum Calcium Granules and Putative Nanobacteria: Demonstration of a Dual Inhibition-Seeding Concept

et al. 2009

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Serum-derived granulations and purported nanobacteria (NB) are pleomorphic apatite structures shown to resemble calcium granules widely distributed in nature. They appear to be assembled through a dual inhibitory-seeding mechanism involving proteinaceous factors, as determined by protease (trypsin and chymotrypsin) and heat inactivation studies. When inoculated into cell culture medium, the purified proteins fetuin-A and albumin fail to induce mineralization, but they will readily combine with exogenously added calcium and phosphate, even in submillimolar amounts, to form complexes that will undergo morphological transitions from nanoparticles to spindles, films, and aggregates. As a mineralization inhibitor, fetuin-A is much more potent than albumin, and it will only seed particles at higher mineral-to-protein concentrations. Both proteins display a bell-shaped, dose-dependent relationship, indicative of the same dual inhibitory-seeding mechanism seen with whole serum. As ascertained by both seeding experiments and gel electrophoresis, fetuin-A is not only more dominant but it appears to compete avidly for nanoparticle binding at the expense of albumin. The nanoparticles formed in the presence of fetuin-A are smaller than their albumin counterparts, and they have a greater tendency to display a multi-layered ring morphology. In comparison, the particles seeded by albumin appear mostly incomplete, with single walls. Chemically, spectroscopically, and morphologically, the protein-mineral particles resemble closely serum granules and NB. These particles are thus seen to undergo an amorphous to crystalline transformation, the kinetics and completeness of which depend on the protein-to-mineral ratios, with low ratios favoring faster conversion to crystals. Our results point to a dual inhibitory-seeding, de-repression model for the assembly of particles in supersaturated solutions like serum. The presence of proteins and other inhibitory factors tend to block apatite nuclei formation or to stabilize the nascent nuclei as amorphous or semi-crystalline spherical nanoparticles, until the same inhibitory influences are overwhelmed or de-repressed, whereby the apatite nuclei grow in size to coalesce into crystalline spindles and films—a mechanism that may explain not only the formation of calcium granules in nature but also normal or ectopic calcification in the body.

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Investigation of biophysical characteristics of diabetic living eye tissues using PA-FTIR-spectroscopy

Cited by 7 publications

References 1 publication

Bions: A Family of Biomimetic Mineralo-Organic Complexes Derived from Biological Fluids

Bions: A Family of Biomimetic Mineralo-Organic Complexes Derived from Biological Fluids

Characterization of Granulations of Calcium and Apatite in Serum as Pleomorphic Mineralo-Protein Complexes and as Precursors of Putative Nanobacteria

Fetuin-A/Albumin-Mineral Complexes Resembling Serum Calcium Granules and Putative Nanobacteria: Demonstration of a Dual Inhibition-Seeding Concept

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