Light-induced replication of nanobacteria: a preliminary report.

Abstract

Objective: The purpose of the present study was to investigate the effect of light on nanobacteria.

Background data: Since their first description in literature, it is not clear whether the nanoparticles called "nanobacteria" are alive or not. The 80-1,000-nm-sized spherical particles are protected by a crystalline carbonate apatite shell and are culturable in cell culture media. Present in mammalians, including humans, nanobacteria seem to cause diseases related to biomineralization processes. Mesoscopic structures found on Martian meteorites and terrestrial rocks indicated that nanobacteria-like biological objects forming apatite, a material fairly transparent to visible light, could have been present on the primitive Earth during an era with the sun as the principal terrestrial energy source.

Materials and methods: To evaluate possible biomedical effects of therapeutically relevant irradiation sources on nanobacteria, we irradiated nanobacteria cultures with polarized light and laser-light at low, nonthermal energy density levels.

Results: Our observations indicated that nanobacteria are alive. Polarized white light was found to clearly accelerate their replication in vitro, resulting in significant dose-dependent increases in the turbidity of the cultures, compared to nonirradiated controls. Laser irradiation did not affect their replication.

Conclusion: The possibility that primordial and present nanobacteria could have been not only exposed to, but actively harvested, solar irradiation for their own development suggests itself. Considering that there exists no published material on the action of light on nanobacteria, the reported effects are expected to have an impact on modeling biomineralization processes, associated photoreceptor mechanisms, and astrobiological and evolutionary theories-on Earth and in space.