Nautilus pompilius

Suzuki, T. Fukuta, H. Nagato, H. Umekawa, M. Arginine kinase from Nautilus pompilius, a living fossil. Site-directed mutagenesis studies on the role of amino acid residues in the guanidino specificity region. J. Biol. Chem., 275, 23884-23890 (2000)... 

Voss-Foucart, M. F. Essais de solubilisation et de fractionnement d une conchioline (nacre murale de Nautilus pompilius, mollusque cephalopode). Comp. Biochem. Physiol. 26, 877 (1968)... 

Crenshaw, M. A., Ristedt, H. The histochemical localization of reactive groups in septal nacre from Nautilus pompilius L. In The mechanisms of mineralization in the invertebrates and plants. Watabe, N., Wilbur, K. M. (eds). The Belle W. Baruch Library in Marine Science, Vol 5, pp. 355. University South Carolina Press 1976... 

To test this supposition the shell of Nautilus pompilius (mollusc) containing almost 3% organic matter was subjected to pyrolysis at temperatures of up to 500 °C for periods of several hours and days. The experiments were performed under dry conditions and in the presence of distilled water. Sortie of the data are compiled in Table 1. 

Nautilus pompilius deposits a shell composed entirely of aragonite. Experiments95-97 conducted at temperatures between 150° and 900 °C showed the shell aragonite to be stable for a few hours at temperatures of up to 300 °C even under aqueous conditions. Above 300 °C a rapid transformation into calcite was observed... 

Fig. 7. Thermal decomposition rate of shell organic matrix (Nautilus pompilius) at 150 °C in the presence of water. Individual amino acids are reported in residues/1000 and total amino acid concentration in pmol/g numbers on the ordinate are residues/1000 and pmol/g, respectively. Graph on the left is hydrolyzed fraction of total shell material after thermal treatment and graph on the right the unhydrolyzed fraction in the water...

In conclusion thermal degradation studies on Nautilus pompilius indicate that mineralizing matrix and aragonite shell represent a true structural entity. By the sharing of oxygens in protein and mineral lattices we will generate phase boundaries of the type that are present, for instance, in the common clay mineral kaolinite. Here, aluminum octahedra and silica tetrahedra incorporate the same oxygens and hydroxyls, and layers composed of octahedra and tetrahedra arise (Fig. 13). 

Chemical studies on Nautilus pompilius (a cephalopod) and Mercenaria mercenaria (a clam) indicate that matrix proteins are composed of two structural units (1) a polypeptide with a strong affinity to Ca2+ ions which is soluble in strong CaCl2 solutions, and (2) a high molecular weight protein insoluble in CaCl2 with no affinity to calcium and which is arranged in the form of sheets and layers. 

Fields, J.H.A. Some catalytic and regulatory properties of pyruvate kinase from the spadix and retractor muscles of Nautilus pompilius. Pac. Sci., 36, 315-324 (1982)... 

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