The mineral phase in the cuticles of two species of Crustacea consists of magnesium calcite, amorphous calcium carbonate, and amorphous calcium phosphate

Becker, Alexander; Ziegler, Andreas; Epple, Matthias

doi:10.1039/b412062k

Cited by 140 publications

(137 citation statements)

References 39 publications

Supporting

Mentioning

121

Contrasting

Unclassified

Order By: Relevance

“…At intra-molt stage, this content increases immediately to approximately 66 wt % and then decreases to Ϸ35 wt % and approximately 25 wt % in stages 3 and 4, respectively. The organic content in inter-molt is only Ϸ19 wt %, which is close to a previously reported value, 13 wt % (26). The maximum in organic component coincides with the initiation of phase transformation.…”

Section: Resultssupporting

confidence: 64%

Magnesium-aspartate-based crystallization switch inspired from shell molt of crustacean

Tao

Zhou

Zhang

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

128

124

View full text Add to dashboard Cite

Many animals such as crustacean periodically undergo cyclic molt of the exoskeleton. During this process, amorphous calcium mineral phases are biologically stabilized by magnesium and are reserved for the subsequent rapid formation of new shell tissue. However, it is a mystery how living organisms can regulate the transition of the precursor phases precisely. We reveal that the shell mineralization from the magnesium stabilized precursors is associated with the presence of Asp-rich proteins. It is suggested that a cooperative effect of magnesium and Asp-rich compound can result into a crystallization switch in biomineralization. Our in vitro experiments confirm that magnesium increases the lifetime of amorphous calcium carbonate and calcium phosphate in solution so that the crystallization can be temporarily switched off. Although Asp monomer alone inhibits the crystallization of pure amorphous calcium minerals, it actually reduces the stability of the magnesium-stabilized precursors to switch on the transformation from the amorphous to crystallized phases. These modification effects on crystallization kinetics can be understood by an Asp-enhanced magnesium desolvation model. The interesting magnesium-Asp-based switch is a biologically inspired lesson from nature, which can be developed into an advanced strategy to control material fabrications.biomineralization ͉ calcium biominerals ͉ phase transformation

show abstract

Section: Resultssupporting

confidence: 64%

Magnesium-aspartate-based crystallization switch inspired from shell molt of crustacean

Tao

Zhou

Zhang

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

128

124

View full text Add to dashboard Cite

show abstract

“…Both experimental and computational investigations in the literature provided evidence indicating that calcite crystals with low concentrations of Mg are stable in structure (19,(69)(70)(71); these studies, however, predicted that high concentrations of Mg (≥ ∼50 atom %) may prevent crystal formation because of the increasing structural stiffness and distortion resulting from the random Mg substitution of Ca (72,73). Recent studies (73) using computational methods reported that substituting Ca by Mg in calcite crystals can alter the cation-C and the cation-cation interatomic distances significantly and cause local tilt of the CO 3 2− groups while maintaining the C-O (within the CO 3 2− ) and the cation-O bond lengths constant.…”

Section: Resultsmentioning

confidence: 99%

Testing the cation-hydration effect on the crystallization of Ca–Mg–CO ₃ systems

Yan

Zhang

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

144

134

View full text Add to dashboard Cite

Dolomite and magnesite are simple anhydrous calcium and/or magnesium carbonate minerals occurring mostly at Earth surfaces. However, laboratory synthesis of neither species at ambient temperature and pressure conditions has been proven practically possible, and the lack of success was assumed to be related to the strong solvation shells of magnesium ions in aqueous media. Here, we report the synthesis of MgCO 3 and Mg x Ca (1−x) CO 3 (0 < x < 1) solid phases at ambient conditions in the absence of water. Experiments were carried out in dry organic solvent, and the results showed that, although anhydrous phases were readily precipitated in the water-free environment, the precipitates' crystallinity was highly dependent on the Mg molar percentage content in the solution. In specific, magnesian calcite dominated in low [Mg 2+ (1−x) CO 3 were formed. These findings exposed a previously unrecognized intrinsic barrier for Mg 2+ and CO 3 2− to develop long-range orders at ambient conditions and suggested that the long-held belief of cation-hydration inhibition on dolomite and magnesite mineralization needed to be reevaluated. Our study provides significant insight into the long-standing "dolomite problem" in geochemistry and mineralogy and may promote a better understanding of the fundamental chemistry in biomineralization and mineral-carbonation processes.sedimentary geology | carbon sequestration | nonaqueous solvent R arely is there a geological challenge that has endured as long a search for answers as the "dolomite problem" has. Identified more than 220 y ago by the French mineralogist Déodat de Dolomieu, the calcium magnesium carbonate mineral known as dolomite [CaMg(CO 3 ) 2 ] has since been synthesized repeatedly but exclusively at high-temperature and, in some instances, highpressure conditions (1-4). However, in many cases other than igneous-originated carbonatite and deep-burial dolomitization, the formation of dolomitic phases (e.g., microbial and cave deposits) are certainly not associated with such high-temperature and/or -pressure environments (5-8). This obvious discrepancy, compounded by the sharp contrast of massive ancient dolomite formations to the scarcity of modern observations, prompted an arduous search for answers for the past two centuries and, because of a lack of success, has been referred to as the dolomite problem (6, 9-16). Our inability to form dolomite at ambient conditions is hardly the only challenge in mineralogy; a similar situation exists in the case of pure magnesium carbonate [magnesite (MgCO 3 )], which has posed the same level of difficulty to nucleate and grow at room temperature and atmospheric pressure in laboratories but frequently occurs in natural sedimentary settings at earth (sub)surfaces. Interestingly, both dolomite and magnesite belong to the mineral class of anhydrous carbonates. Thus, it becomes logical to surmise that the dolomite problem and the magnesite problem probably share the same root, that is, the difficulty to incorporate unhydrated magnesium ions i...

show abstract

“…Both structural organization and type and degree of mineralization observed in cuticle from different Crustacea species have been positively correlated to ecophysiological adaptations like defensive strategies (Becker et al, 2005;Hild et al, 2008), special habitats (Hild et al, 2008;Seidl et al, 2011) or economy of material and thus energy . The organization of the cuticle forming the dorsal carapace of the crab C. pagurus suggests a high resistance against mechanical loads, especially loads applied in the direction perpendicular to the surface.…”

mentioning

confidence: 99%

Correlation of structure, composition and local mechanical properties in the dorsal carapace of the edible crab Cancer pagurus

Fabritius¹,

Karsten²,

Balasundaram³

et al. 2012

Zeitschrift Für Kristallographie - Crystalline Materials

View full text Add to dashboard Cite

Abstract. The exoskeleton of crustaceans is formed by the cuticle, a chitin-protein-based nano-composite with hierarchical organization over at least eight levels. On the molecular level, it consists of chitin associated with proteins forming fibres, which are organized in the form of twisted plywood. On the higher levels, the twisted plywood organization is modified and forms skeletal elements with elaborate functions. The load-bearing parts of crustacean cuticle are reinforced with both crystalline and amorphous biominerals. During evolution, all parts of the exoskeleton were optimized to fulfill different functions according to different ecophysiological strains faced by the animals. This is achieved by modifications in microstructure and chemical composition. In order to understand the relationship between structure, composition, mechanical properties and function we structurally characterized cuticle from the dorsal carapace of the edible crab Cancer pagurus using light and scanning electron microscopy (SEM). The local chemical composition was investigated using energy dispersive X-ray spectroscopy (EDX) and confocal m-Raman spectroscopy. Nanoindentation tests were performed to study the resulting local mechanical properties. The results show local differences in structure on several levels of the structural hierarchy in combination with a very heterogeneous mineralization. The distal exocuticle is mineralized with calcite, followed by a layer containing a magnesium, phosphate and carbonate rich phase and ACC in the proximal part. The endocuticle contains magnesian calcite and ACC in special regions below the exocuticle. Structure and mineral phase are reflected in the local stiffness and hardness of the respective cuticle regions. The heterogeneity of structural organization and mechanical properties suggests remarkable consequences for the mechanical behaviour of the bulk material.

show abstract

The mineral phase in the cuticles of two species of Crustacea consists of magnesium calcite, amorphous calcium carbonate, and amorphous calcium phosphate

Cited by 140 publications

References 39 publications

Magnesium-aspartate-based crystallization switch inspired from shell molt of crustacean

Magnesium-aspartate-based crystallization switch inspired from shell molt of crustacean

Testing the cation-hydration effect on the crystallization of Ca–Mg–CO ₃ systems

Correlation of structure, composition and local mechanical properties in the dorsal carapace of the edible crab Cancer pagurus

Contact Info

Product

Resources

About

The mineral phase in the cuticles of two species of Crustacea consists of magnesium calcite, amorphous calcium carbonate, and amorphous calcium phosphate

Cited by 140 publications

References 39 publications

Magnesium-aspartate-based crystallization switch inspired from shell molt of crustacean

Magnesium-aspartate-based crystallization switch inspired from shell molt of crustacean

Testing the cation-hydration effect on the crystallization of Ca–Mg–CO 3 systems

Correlation of structure, composition and local mechanical properties in the dorsal carapace of the edible crab Cancer pagurus

Contact Info

Product

Resources

About

Testing the cation-hydration effect on the crystallization of Ca–Mg–CO ₃ systems