First Evidence of Ommochromes in Bivalves: the Case of the Edible Oyster Crassostrea Gigas

Abstract

Among the great variety of pigments found in living beings in general, and more particularly in molluscs, the ommochromes are a family of unknown organic dyes and until now still too little studied. Several lines of physicochemical and structural evidence allowed us here to complete the composition of the purple colour of shell patterns of Crassostrea gigas, highlighting an intriguing association of ommochromes and porphyrins, corroborated by the presence of known genes associated with their biosynthetic pathways. We describe here our pathway to demonstrate for the first time the presence of ommochromes in a bivalve.

A Review of Bioactive Compounds in Oyster Shell and Tissues

“…It comprises macromolecules such as polysaccharides (mostly chitin), water soluble and insoluble proteins (including glycol proteins), and lipids, in addition to smaller molecules such as pigments, free amino acids, and short peptides ( Marin et al, 2012 ). These biomolecules are distinguished based on extraction methods and solubility, with matrix types including the water-soluble matrix (WSM), ethanol-soluble matrix (ESM), acid-soluble matrix (ASM), acid-insoluble matrix (AIM), ethylenediaminetetraacetic acid (EDTA)-soluble matrix (EDTASM), EDTA-insoluble matrix (EDTAIM), and fat-soluble matrix (FSM; ( Bonnard, 2021 ). In addition to regulating biomineralization, the WSM also promotes nacre biological activities such as cell recruitment, differentiation, and stimulation.…”

“…Oysters reduce the eutrophication of water bodies and may reduce the amounts of metal cations, plastic particles, and other chemicals in water. Oyster shells can be used to remove pollutants such as certain anions (phosphate [PO 4 3- ], F − , and NO 3 − ) and cations (Cu, Ni, Mn, As, U, Th, Pb, Fe, Zn, and Co), antibiotics, neurotoxins, and excess nitrogen (N) ( Bonnard, 2021 ). Oyster shell powder has also been used to improve the water quality of lakes by facilitating the removal of algal blooms.…”

“…Combination of oyster shell and Polyvinyl chloride (PVC), neutralizes harmful hydrochloric acid which results from PVC incineration mimicking the activity of commercially available calcium carbonate and with CaCl2 as by-products. Oyster shell wastes are also used in material synthesis (Filler incomposite, foaming agent, template, support for catalysts, source of sodium, calcium, and, calcium carbonate) and used as building materials (Limestone and aggregate) and cosmetic ingredients ( Bonnard, 2021 ).…”

Identifying genes associated with genetic control of color polymorphism in the pearl oyster Pinctada margaritifera var. cumingii (Linnaeus 1758) using a comparative whole genome pool‐sequencing approach

“…Species with economical interest have historically been used by scientists to understand fundamental biological mechanisms such as color variation in bivalves. Marine bivalves, like the scallops Patinopecten yessoensis (Jay, 1857) (Chang et al, 2007 ; Ding et al, 2015 ; Sun et al, 2015 ; Yuan et al, 2021 ), Argopecten irradians (Lamarck, 1819) (Adamkewicz & Castgna, 1988 ; Du et al, 2017 ), or the Pacific oyster Crassostrea gigas (Thunberg, 1793) (Aguilera et al, 2014 ; Bonnard et al, 2020 , 2021 ; Feng et al, 2015 , 2018 ; Hu et al, 2021 ; Song et al, 2017 ) have already received much attention for the elucidation of their pigmentation pathways. More recently, the black‐lipped pearl oyster Pinctada margaritifera var.…”