Calcium-Phosphate Biomineralization Induced by Alkaline Phosphatase Activity in Escherichia coli: Localization, Kinetics, and Potential Signatures in the Fossil Record

Frontiers in Digital Humanities

Duprat, Elodie³  Coelho, Cristina⁴  riel⁴  Fé⁵  Cosmidis, Julie⁵  Benzerara, Karim^1,10  rard, Cé^1,10  Guyot, Franç^1,13  line^1,13  Guigner, Jean-Michel^1,14  ois^1,14  Babonneau, Florence^1,15  Skouri-Panet, Fé^1,15 

[1] Pierre et Marie Curie, Centre National de la Recherche Scientifique, CollèPierre et Marie Curie, FR Centre National de la Recherche Scientifique 2482, Paris, France;Pierre et Marie Curie, IRD UMR 206, Paris, France;Histoire Naturelle, UniversitéInstitut de MinéInstitut des MatéLaboratoire de Chimie de la Matièe de Paris, Universitége de France, UMR 7574, Paris, France;ralogie, de Physique des Matére Condensériaux de Paris-Centre, Universitériaux, et de Cosmochimie, Sorbonne Universités, UMR 7590, Centre National de la Recherche Scientifique, Muséum National d'

关键词: Biomineralization;    hydroxyapatite;    Alkaline Phosphatase;    Phosphorites;    Microbial fossils;   

DOI  :  10.3389/feart.2015.00084

学科分类：社会科学、人文和艺术（综合）

来源: Frontiers

【 摘 要 】

Bacteria are thought to play an important role in the formation of calcium-phosphate minerals composing marine phosphorites, as supported by the common occurrence of fossil microbes in these rocks. Phosphatase enzymes may play a key role in this process. Indeed, they may increase the supersaturation with respect to Ca-phosphates by releasing orthophosphate ions following hydrolysis of organic phosphorus. However, several questions remain unanswered about the cellular-level mechanisms involved in this model, and its potential signatures in the mineral products. We studied Ca-phosphate precipitation by different strains of Escherichia coli which were genetically modified to differ in the abundance and cellular localization of the alkaline phosphatase (PHO A) produced. The mineral precipitated by either E. coli or purified PHO A was invariably identified as a carbonate-free non-stoichiometric hydroxyapatite. However, the bacterial precipitates could be discriminated from the ones formed by purified PHO A at the nano-scale. PHO A localization was shown to influence the pattern of Ca-phosphate nucleation and growth. Finally, the rate of calcification was proved to be consistent with the PHO A enzyme kinetics. Overall, this study provides mechanistic keys to better understand phosphogenesis in the environment, and experimental references to better interpret the microbial fossil record in phosphorites.

【 授权许可】

CC BY