Biomacromolecules within bivalve shells: Is chitin abundant?

Agbaje, Oluwatoosin B. A.; Shir, Ira Ben; Zax, David B.; Schmidt, Asher; Jacob, Dorrit E.

doi:10.1016/j.actbio.2018.09.009

Cited by 51 publications

(53 citation statements)

References 74 publications

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“…Using the results of cryo-transmission electron microsocopy, Levi-Kalisman et al (2001) postulate that the interlamellar sheets of nacre are made up largely of chitin, which is perhaps associated with acidic proteins. In contrast to this hypothesis, using multiple analytical techniques, Agbaje et al (2018) were unable to demonstrate significant chitin in nacre or other microstructures, but they did not include shells with foliated microstructures in their study. Indirect evidence exists that chitin is present in this microstructure.…”

Section: Discussionmentioning

confidence: 93%

Folian-cv1 Is a Member of a Highly Acidic Phosphoprotein Class Derived From the Foliated Layer of the Eastern Oyster (Crassostrea virginica) Shell and Identified in Hemocytes and Mantle

et al. 2019

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The proteins derived from the foliated shell layer of the oyster, Crassostrea virginica, are unusually acidic and highly phosphorylated. Here we report the identification of a gene encoding a member of this class of phosphoproteins that we collectively refer to as folian. Using an in silico approach, a virtual probe was constructed from an N-terminal sequence (DEADAGD) determined for a 48 kDa folian phosphoprotein and used to screen an oyster EST databank. A sequence that matched the N-terminus of the 48 kDa protein was found and used to identify the full-length gene from a C. virginica BAC library. The molecular weight of the deduced gene product is 32 kDa and was named folian-cv1. Genomic Southern analysis revealed two variants of the gene. The mature protein is composed of 43.3% Asp, 32.6% Ser, and 9.1% Glu with 37.5% of the amino acids of the protein potentially phosphorylated. The primary sequence of folian-cv1 is organized in blocks, with a short relatively hydrophobic block at the N-terminus and with the remainder containing low complexity regions largely dominated by aspartic acid and serine. Overall, the protein is predicted to be highly disordered. PCR and sequence analyses identified folian-cv1 expression in the mantle and hemocytes. Immuno-histochemical staining of mantle tissue reveals that cells of the shell-facing epithelium and in the periostracal groove secrete a continuous layer of folian-positive material and that folian-positive hemocytes move through the mantle epithelium. The function in shell formation of folian proteins including folian-cv1 is not known. However, based on the complexity of this class of proteins and the two methods of their delivery to the region of shell formation, it is possible they are involved in diverse ways in this process.

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Section: Discussionmentioning

confidence: 93%

Folian-cv1 Is a Member of a Highly Acidic Phosphoprotein Class Derived From the Foliated Layer of the Eastern Oyster (Crassostrea virginica) Shell and Identified in Hemocytes and Mantle

et al. 2019

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“…3 While calcium carbonate is the dominant chemical constituent of the shells, minor inorganic trace elements are common in different species of bivalves. [3][4][5][6][7][8][9] Owing to the presence of the shells with multiple functional attributes, the snails and mussels qualify as ecosystem engineers modifying the constituents and the interactions of the freshwater community. [10][11][12] Due to the phenotypic variation in traits, the shells of the mussels are vulnerable to the selection process for renement with higher adaptive value.…”

Section: Introductionmentioning

confidence: 99%

An insight into the structure, composition and hardness of a biological material: the shell of freshwater mussels

et al. 2020

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“…However, a recent solid‐state NMR study showed that chitin in the organic membrane is not as abundant as previously proposed, to the extent that it may even be absent in some species and instead consists primarily of proteinaceous matter that shows structural similarities with spider silk or collagen depending on the species (Agbaje et al . ). Nacre has exceptional mechanical properties, such as high hardness (0.69–11.4 GPa) and fracture toughness (3.3–9 MPa m −1 ; Sun and Bhushan ), as well as high stiffness.…”

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confidence: 97%

Overcoming Challenges Associated with the Analysis of Nacre by Atom Probe Tomography

Eder

Otter²,

Yang

et al. 2019

Geostandard Geoanalytic Res

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In this study atom probe tomography was used to study nacre, an important biocomposite material that is challenging to prepare and analyse by atom probe and, when successful, yields data that is challenging to interpret. It was found that these challenges mainly arise from the insulating and heterogeneous nano‐scale properties of nacre. We outline our current best practice for preparing and running atom probe tips, such as using a low acceleration voltage (< 3 kV) and current (≤ 50 pA) to avoid damage to the microstructure, and using transmission electron microscopy to confirm that the region of interest is located close to the apex of the atom probe tip. Optimisation of the preparation parameters led to several successful atom probe experiments, with one of the data sets containing part of an organic membrane and others showing organic inclusions within the reconstruction.

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Biomacromolecules within bivalve shells: Is chitin abundant?

Cited by 51 publications

References 74 publications

Folian-cv1 Is a Member of a Highly Acidic Phosphoprotein Class Derived From the Foliated Layer of the Eastern Oyster (Crassostrea virginica) Shell and Identified in Hemocytes and Mantle

Folian-cv1 Is a Member of a Highly Acidic Phosphoprotein Class Derived From the Foliated Layer of the Eastern Oyster (Crassostrea virginica) Shell and Identified in Hemocytes and Mantle

An insight into the structure, composition and hardness of a biological material: the shell of freshwater mussels

Overcoming Challenges Associated with the Analysis of Nacre by Atom Probe Tomography

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