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Mineral fine structure defends the cuticle of the American lobster ( Homarus americanus ). J.G. Kunkel, W. Nagel, M. Jercinovic UMass Amherst, MA. Calcite vs Apatite : Contrasting functions in lobster cuticle. An Apatite for Lobster?. Calcite and Amorphous Calcium Carbonate. - PowerPoint PPT Presentation
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Mineral fine structure defends the cuticle of the American lobster (Homarus americanus)
J.G. Kunkel, W. Nagel, M. JercinovicUMass Amherst, MA
An Apatite for Lobster?
Calcite and Amorphous Calcium Carbonate
Calcite vs Apatite: Contrasting functions in lobster cuticle
Bone (Carbonate Apatite) in Canals and Trabeculae
Biomineralization Models
Lobster as a model system in study of composite materials
Properties are computed for a hierarchically averaged material! (Raabe 2010) Dusseldorf (Raabe), Ulm (Ziegler) and Linz (Hild)
Cuticle Heterogeneity: Organules - Bristles and
Dermal Glands1
1
2
2
3
3Three or four stadia of organule development: 10% linear growth requires 21% increase per molt.
Electron Microprobe Images of Lobster Minerals
Flexible Carbonate-Apatite Formula
Ca10-x+u(PO4)6-x(CO3)x(OH)2-x+2u • z H2O
BoneTrabecula:
Canals andTrabeculae
Canal (False Color) Mineral ID
Canal (False Color) Mineral ID
Major Conclusion:
• Lobsters use ‘apatite’ for critical skeletal structures.– Apatite: Ca5(PO4)3 OH Ca:P = 5:3 Ca/P = 1.667– Dermal gland and neurite canals - Ca:P 2:1 - - 7:1– A flexible carbonate apatite formula is followed.
– Ca10-x+u(PO4)6-x(CO3)x(OH)2-x+2u • z H2O
x u z Ca:P Ca/P CO3/Ca1 1 1 2:1 2.0 0.102 1 1 9:4 2.25 0.223 1 1 8:3 2.67 0.3754 1 1 7:2 3.5 0.5715 2 1 7:1 7.0 0.714
Major Conclusion about divalent Cations:• Ca has an even density across the calcite layer.• Mg + other divalent cations decline in density toward surface.• Carbonate dissolution at cuticle surface makes surface alkaline.
Artificial Lesions
d1 ----------------------------- d34 --------------------------------------- d59
d1 ========================== d25 Aug 26 Sept 29 Oct 24
Probing Protocol for Ion and O2 Flux
Artificial Lesion H+ and Ca2+ Flux in pH 8.2 Bkg
Mineral Model of Lobster Cuticle
Acknowledgements• UMass Amherst, Biology
Al Shipley, Mike Zeitchek, Amanda Sceusa, Edwin Han, Sunyoung Yang.
• UMass Amherst, GeosciencesMike Jercinovic Sheila SeamensAnna Keskula
• LM-University, Munich, GermanyWolfram Nagel, Physiology
• Johannes Kepler University, Linz, Austria Sabine Hild, Polymerwissenschaft InstituteKatja Huemer
• URI: Kathy Castro, Barbara Somers, Thomas Angell• Maine DMR: Carl Wilson, Maine Ventless Trap program