Abstract
Putative living entities called nanobacteria (NB) are unusual for their small sizes (50–500 nm), pleomorphic nature, and accumulation of hydroxyapatite (HAP), and have been implicated in numerous diseases involving extraskeletal calcification. By adding precipitating ions to cell culture medium containing serum, mineral nanoparticles are generated that are morphologically and chemically identical to the so-called NB. These nanoparticles are shown here to be formed of amorphous mineral complexes containing calcium as well as other ions like carbonate, which then rapidly acquire phosphate, forming HAP. The main constituent proteins of serum-derived NB are albumin, fetuin-A, and apolipoprotein A1, but their involvement appears circumstantial since so-called NB from different body fluids harbor other proteins. Accordingly, by passage through various culture media, the protein composition of these particles can be modulated. Immunoblotting experiments reveal that antibodies deemed specific for NB react in fact with either albumin, fetuin-A, or both, indicating that previous studies using these reagents may have detected these serum proteins from the same as well as different species, with human tissue nanoparticles presumably absorbing bovine serum antigens from the culture medium. Both fetal bovine serum and human serum, used earlier by other investigators as sources of NB, paradoxically inhibit the formation of these entities, and this inhibition is trypsin-sensitive, indicating a role for proteins in this inhibitory process. Fetuin-A, and to a lesser degree albumin, inhibit nanoparticle formation, an inhibition that is overcome with time, ending with formation of the so-called NB. Together, these data demonstrate that NB are most likely formed by calcium or apatite crystallization inhibitors that are somehow overwhelmed by excess calcium or calcium phosphate found in culture medium or in body fluids, thereby becoming seeds for calcification. The structures described earlier as NB may thus represent remnants and by-products of physiological mechanisms used for calcium homeostasis, a concept which explains the vast body of NB literature as well as explains the true origin of NB as lifeless protein-mineralo entities with questionable role in pathogenesis.
Highlights
Nanobacteria (NB), bacterial entities with unusually small sizes and widespread distribution in animals and humans [1,2], have been implicated in numerous diseases and as infectious agents associated with body fluids, blood infusion products, and vaccines [3,4,5,6,7]
Rather than just using published protocols to study NB as complex and ambiguous entities derived in culture, we attempted a reverse strategy by first generating well-defined amorphous mineral complexes— particles that we have labeled nanobacteria-like particles (NLP) to distinguish them from the published NB
This approach can be justified by the fact that all NB cultures to date have originated from the introduction of some exogenous factor(s), be them serum, some other kind of body fluid, or pulverized tissue homogenates, to normal culture media that may very well have perturbed the local equilibrium of calcium, resulting in slow and ambiguous calcium and HAP precipitations that are described as NB [1,2,3,4,5,6]
Summary
Nanobacteria (NB), bacterial entities with unusually small sizes and widespread distribution in animals and humans [1,2], have been implicated in numerous diseases and as infectious agents associated with body fluids, blood infusion products, and vaccines [3,4,5,6,7]. These same entities have been linked to the earlier ‘‘nannobacteria’’ [8,9] found in geological samples as well as fossil forms found on meteorites [10], indicating that they may represent primitive or overlooked life precursors. These authors further showed that NB, when cultured in vitro without serum, displayed a simple protein profile that differed markedly from the kind of complex coating normally associated with living microorganisms, implying that the NB-associated proteins might have been derived from apatite-binding proteins present in saliva
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
