Biomineralization organized organic substrates

Looking at the literature in the field of biomineralization, one notices, that the majority of articles is descriptive in nature. On the basis of electron micrographs or thin section studies, the intricate relationships between mineral phase and organic matrix are investigated. Other papers deal with the chemical composition of the mineralized tissue and the minerals. Only a few authors address themselves to the question of metal ion transport mechanisms in cellular systems and the solid state principles involved in mineral deposition on organic substrates. All three sets of information, however, are essential to understand calcification processes. It appears, therefore, that information on the functionality of metal ions in living systems and their role in mineral deposition are particularly desired in this area of research. 

A wide variety of minerals are deposited by organisms including metal oxides, sulfides, carbonates, and phosphates (6). Thus, biomineralization appears to be a general phenomenon the concepts of which should be applicable to position of minerals not found in nature. Furthermore, the mineral deposition process is not under direct cellular control and only the structure and composition of the nucleation protein appear to be controlling the mineralization. With this rationale, our researches have focused on understandmg how organic substrates control nucleation and crystal growth of both biominei s and technically important minerals (7-ii). 

Biomineralization. In biomineralization, inorganic elements are extracted from the environment and selectively precipitated by organisms. Usually, templates consisting of suitable macro-molecules serve as a substrate for the heterogeneous nu-cleation of bulk mineralized structures such as bone, teeth and shells. Biological control mechanisms are reflected not only in the type of the mineral phase formed but also in its morphology and crystallographic orientation (Mann et al., 1989 Lowenstamm and Weiner, 1989). Two examples (perhaps oversimplified) may illustrate the principle (Ochial, 1991) ... 

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