Naslov
Magnesium calcite, feldspars and amphiboles in embryos, pluteus and adult Antarctic sea urchins sterechinus neumayeri

Autori
Medaković, Davorin ; Popović, Stanko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Learning from nature how to design new implantable biomaterials: from biomineralization fundamentals to biomimetic materials and processing route / Reis, Rui L. - Alvor : NATO / Advanced Study Institute, 2003, 75-75

Skup
Learning from nature how to design new implantable biomaterials: from biomineralization fundamentals to biomimetic materials and processing routes

Mjesto i datum
Alvor, Portugal, 13.10.2003. - 24.10.2003

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Antarctic; Sterechinus neumayeri; Biomineralization; Magnesium calcite; Calcite; Dolomite; Feldspars; Amphiboles

Sažetak
X-ray powder diffraction (XRD) was used to study the mineral composition of embryos, early pluteus and adult Antarctic sea urchins Sterechinus neumayeri. The contents of minerals were determined by quantitative X-ray phase analysis. The fraction of Mg in magnesium calcite was measured from the angular shifts of diffraction lines in relation to the angular position of the same diffraction lines of pure calcite. It was found that embryos and pluteus of S.neumayeri beside dominant amorphous components contained small amounts of calcite, traces of magnesite, dolomite, feldspars and amphiboles. Magnesium calcite was the dominant component of the skeleton and spines of adults. It was estimated that the fraction of Mg was 0.08ą0.01 in spines and 0.13ą0.02 in the skeleton. The adult urchins also contained in their calcified structures, like embryos and larvae, traces of feldspars and amphiboles. Such a combination of different minerals in invertebrate embryos, larvae or adults were not registered in recent literature. Unfertilized eggs contained of organic amorphous component with small amounts of H, halite and S, sylvite, that remained in the samples during preperation for XRD. Biomineralization starts by incorporation of the Cm, magnesium calcite, M, magnesite, D, dolomite, F, feldspars and A, amphiboles in the four cell morula stage. During embryogenesis morphological changes of embryos were not followed by changes in fraction of particular crystalline phases and minerals. Small increases of magnesium calcite and other minerals are registered only in the early gastrula stage 168 h after fertilizazion (af). A rapid calcification and formation of the larval skeleton are registered 500 h af, in the four-armed pluteus larva. Intensive increasing of magnesium calcite is followed by adequately decreasing of amorphous components. Other minerals of the larval shells are on the constant small values.

Izvorni jezik
Engleski

Znanstvena područja
Geologija, Biologija

POVEZANOST RADA