posted on 2019-09-20, 19:43authored byGrażyna
M. Durak, Michael Laumann, Stefan L. P. Wolf, Atul Pawar, Denis Gebauer, Thomas Böttcher
Biomineralization
is an active, biologically governed process of
mineral formation, established early on in the history of life. The
appearance of biomineralizing organisms heavily influenced the course
of evolution, leading to the development of the large diversity of
the extant taxa. Yet, we are still only beginning to grasp the intricate,
genetically regulated mechanisms involved. Since prokaryotic organisms
were the first to emerge from the primordial environments, we investigated
bacteria–mineral interactions using titration and gas diffusion
systems adapted to emulate conditions, which may have facilitated
the development of biomineralization initially. By screening the minerals
and bacteria from titration experiments with scanning electron microscopy,
we discovered a broad spectrum of behavioral strategies employed by
bacteria confronted with calcification, which fell into three main
categories: (1) evasion of mineralization by the formation of the
biofilm, (2) random embedding into the mineral, and (3) control over
the mineral shape during its formation. The latter phenomenon we termed
pseudo-biomineralization. Our experiments indicate that pseudo-biomineralization
is an active process obligatorily reliant on the external calcifying
conditions and allowing considerable degree of control over mineral
shape, thus producing structures reminiscent of true biominerals.
Here, we describe this notion for the first time, thus providing vital
insight into the genesis of a transitional stage to calcium carbonate-based
biomineralization systems.