Structure, crystallization and mineral composition of sclerites in the alcyonarian coral

Rahman, M. Azizur; Oomori, Tamotsu

doi:10.1016/j.jcrysgro.2008.04.056

Cited by 56 publications

(47 citation statements)

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“…Characteristic Raman bands for calcite and aragonite were assigned as described elsewhere. [6][7][8][9] Calcite and aragonite are two common polymorphs of CaCO3 observed as biominerals.Stony coral forms needle-like aragonite crystals, but soft coral forms only calcite crystals. The protein-induced chemical structure in calcified organisms is an important factor contributing to their growth, but until now no direct evidence has been reported.…”

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Analysis of Protein-induced Calcium Carbonate Crystals in Soft Coral by Near-Field IR Microspectroscopy

Rahman

Oomori

2009

ANAL. SCI.

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Infrared (IR) vibrational spectroscopy is a well-established tool in materials and life-science research. This technique can obtain information regarding fundamentally important microchemical properties. Although it is widely used to analyze microchemical properties, the identification of chemical structure using vibrational spectroscopy at infrared wavelengths has been problematic because of the diffraction limits of conventional infrared microscopy, which result in low spatial resolution. For example, the spatial resolution of infrared (IR) spectroscopy is approximately 10 mm, but that of newly developed near-field IR spectra (NFIR) is 1 mm, or less. Therefore, sub-micrometer to sub-nanometer scale chemical structure analysis is difficult to achieve by conventional IR. Specifically, scientists have been hampered by difficulty to separate protein-associated small chemical compounds from biomineralized organisms. We have overcome this limitation by applying a newly developed nearfield optical technique and near-field optical microscope through NFIR with high spatial resolution. The combination of nearfield microscopy and spectroscopy enables spectra to be obtained with subwavelength spatial resolution for visible light. However, the application of the near-field optical technique to the mid-IR region has only been reported for microscopy thus far.1 The primary reason for this limitation is lack of availability of high-intensity sources and detectors for the IR region.In the present study, this technique was used with a soft coral, Lobophytum crassum, as a model calcifying organism. Soft coral is an important and integral part of marine ecosystems. It has an important role in benthic-pelagic coupling processes as a source of food for demersal grazers and predators, as a host of highly diverse microbial biomass, and as a bioeroder. Soft coral contains small spicules of calcium carbonate, called "sclerites." Sclerites can strengthen the base of the soft coral, and are used by scientists to assist in the identification of soft coral species. Sclerites are the major mineralized structures present in these organisms. To address this importance, in vitro crystallization experiments were carried out in the presence of matrix proteins extracted from sclerites.A supersaturated solution of Ca(HCO3)2 was prepared by purging a stirred aqueous suspension of CaCO3 with carbon dioxide. 2 An aragonitic solution was obtained by adding 50 mM MgCl2 to supersaturated solution. Crystallization experiments were carried out with and without the addition of 700 mg of soluble proteins (extracted from sclerites) to the solution (500 ml). The solutions were then allowed to sit for one month without further manipulation. The protein concentration in the organic matrix was measured by method of Lowry et al. 3 using chicken ovalbumin (Kanto Chemical, Tokyo, Japan) as standard. The precipitate crystals were harvested from the solution after completion of each experiment, and each sample was stored for near-field probing analysis. An aperturele...

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confidence: 99%

“…Characteristic Raman bands for calcite and aragonite were assigned as described elsewhere. [6][7][8][9] Calcite and aragonite are two common polymorphs of CaCO3 observed as biominerals.…”

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confidence: 99%

Analysis of Protein-induced Calcium Carbonate Crystals in Soft Coral by Near-Field IR Microspectroscopy

Rahman

Oomori

2009

ANAL. SCI.

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“…Sclerites of modern octocorals are composed of tightly packed crystals of calcite with variable amount of magnesium (high Mg-calcite) (e.g., Weinbauer and Vellmirov 1995;Rahman and Oomori 2008), but also calcite with an admixture of aragonite or aragonite alone (e.g., Bayer 1955bBayer , 1981a. Stanley et al (2002) conclude that the Mg content in the skeletal calcite of anatomically simple organisms correlates directly with the Mg/Ca ratio of the ancient seawater.…”

Section: Isis Linné-parisis Verrilmentioning

confidence: 99%

The incertae sedis Carpathoporella Dragastan, 1995, from the Lower Cretaceous of Albania: skeletal elements (sclerites, internodes/branches, holdfasts) of colonial octocorals

Schlagintweit¹,

Gawlick

2009

Facies

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“…Calcium carbonate, as one standard model system, has been a focus of recent interest due to its abundance in nature and organisms, such as oyster shells [9][10][11][12], corals [13][14][15], and fish bone [16]. It has wide industrial applications in papers, plastics, rubbers, and paints too [17,18].…”

Section: Introductionmentioning

confidence: 99%

Preparation and structure evolution of bowknot-like calcium carbonate particles in the presence of poly(sodium 4-styrene sulfate)

Xie

Song

Tong

et al. 2012

Journal of Colloid and Interface Science

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Structure, crystallization and mineral composition of sclerites in the alcyonarian coral

Cited by 56 publications

References 30 publications

Analysis of Protein-induced Calcium Carbonate Crystals in Soft Coral by Near-Field IR Microspectroscopy

Analysis of Protein-induced Calcium Carbonate Crystals in Soft Coral by Near-Field IR Microspectroscopy

The incertae sedis Carpathoporella Dragastan, 1995, from the Lower Cretaceous of Albania: skeletal elements (sclerites, internodes/branches, holdfasts) of colonial octocorals

Preparation and structure evolution of bowknot-like calcium carbonate particles in the presence of poly(sodium 4-styrene sulfate)

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