During water intake by the incurrent siphon, food particles are captured by the paired posterior gills (ctenidia) and then carried by the movement of cilia forward to the mouth. Excretion and osmoregulation are performed by a pair of nephridia. Eyespots and other sensory structures are located along the edge of the mantle in some species. The "eyes" are especially conspicuous in scallops (Figure 28.23b). Three pairs of connected ganglia regulate activity of different body structures. One of the functions of the mantle is to secrete the shell. Some bivalves, like oysters and mussels, possess the unique ability to secrete and deposit a calcareous nacre or “mother of pearl” around foreign particles that may enter the mantle cavity. This property has been commercially exploited to produce pearls. More than half of molluscan species are in the class Gastropoda (“stomach foot”), which includes well-known mollusks like snails, slugs, conchs, cowries, limpets, and whelks. Aquatic gastropods include both marine and freshwater species, and all terrestrial mollusks are gastropods. Gastropoda includes shell-bearing species as well as species without shells.

of pearl oyster, a marine bivalve mollusk in the family Pteriidae, the pearl oysters. There are two different color varieties: the Gold-lipped oyster and Pinctada maxima is a species of pearl oyster, a marine bivalve mollusk in the family Pteriidae, the pearl oysters. There are two different color varieties: the Gold-lipped oyster and the Silver-lipped oyster. These bivalves are the largest pearl oysters in the world. They have a very strong inner shell layer composed of nacre, also known as "mother of pearl" and are important to the cultured pearl Pinctada maxima is a species of pearl oyster, a marine bivalve mollusk in the family Pteriidae, the pearl oysters. There are two different color varieties: the Gold-lipped oyster and the Silver-lipped oyster. These bivalves are the largest pearl oysters in the world. They have a very strong inner shell layer composed of nacre, also known as "mother of pearl" and are important to the cultured pearl industry as they are cultivated to produce South Sea pearls. The South Sea pearl or Philippine pearl was declared by Philippine President Fidel Ramos as the national gem in 1996 through Proclamation No. 905. The oyster and pearl are depicted on the reverse side of the Philippine New Generation Currency Series 1,000-peso bill. Pinctada maxima oysters grow very large, up to 12 in (30 cm) in diameter. The two color varieties have different coloration in the outer edge of the interior. This mother of pearl or nacre is responsible for the color of the pearls that the oyster can produce. Water temperature, plankton and sediments determine which color variety is more common in a given area.

oysters, being members of a distinct family, the feathered oysters (Pteriidae). Both cultured pearls and natural pearls can be extracted from pearl oysters Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many (but not all) oysters are in the superfamily Ostreoidea. Some species of oyster are commonly consumed and are regarded as a delicacy in some localities. Some types of pe Almost all shell-bearing mollusks can secrete pearls, yet most are not very valuable. Pearls can form in both saltwater and freshwater environments. Pearl oysters are not closely related to true oysters, being members of a distinct family, the feathered oysters (Pteriidae). Both cultured pearls and natural pearls can be extracted from pearl oysters, though other molluscs, such as the freshwater mussels, also yield pearls of commercial value. The largest pearl-bearing oyster is the marine Pinctada maxima, which is roughly the size of a dinner plate. Not all individual oysters produce pearls. In nature,…

Abstract The silver-lipped pearl oyster, Pinctada maxima, is an iconic bivalve farmed in tropical Australia and South-east Asia to produce high valued South Sea pearls. Here, we present a high-quality, chromosome-level reference genome for P. maxima. The final genome assembly has a total size of 1.27 Gb, with a scaffold N50 length of 65.69 Mb. Using high-throughput chromosome conformation capture (Hi-C) technology, we have anchored 80.99% of the assembly to 14 chromosomes. The BUSCO analysis revealed a high level of accuracy and completeness, identifying 87.9% (n = 4,658) of Mollusca core genes, which exceeds the average completeness of 79.2% reported for other mollusc genomes sequenced and annotated to date. The assembly includes 62.79% repeat elements (809 Mb), and gene annotation predicted 25,752 protein-coding genes. This genomic resource offers a powerful tool for unraveling the molecular mechanisms underlying pearl formation and facilitating continued research into the evolutionary biology of pearl oysters worldwide.

Abalone pearl farming is an aquaculture activity with great potential for future growth and diversification of the global pearl sector, which has been dominated for decades by pearls of marine pearl oysters of the genus Pinctada. Despite this potential, there is a significant lack of knowledge regarding methods for nucleus (bead) seeding and the process of pearl formation in abalone, compared to the well-studied pearl oyster model. To address this problem, this review first compares the main anatomical differences and similarities between both groups of mollusks, particularly those associated with the structure and role of mantle tissue on the synthesis of CaCO3 compounds that integrate the inner nacreous layer. The iridescence (orient) and color properties of nacre in a cultured pearl is particularly related to the microstructure of aragonite crystals during biomineralization in each mollusk group. We then analyze the advantages and disadvantages of the adoption in abalone of methods originally developed for pearl oysters to produce bead-seeded pearls and half-pearls (or mabé pearls). For the red abalone Haliotis rufescens in particular, updated information on commercial production of both bead-seeded and mabé pearls is provided as a case of success for Latin America (Chile). Finally, the current status and future prospects for abalone pearl farming are discussed, assessing technology gaps and challenges to be addressed for the pearl sector to achieve its full potential, par

Background: Despite its economic importance, we have a limited understanding of the molecular mechanisms underlying shell formation in pearl oysters, wherein the calcium carbonate crystals, nacre and prism, are formed in a highly controlled manner. We constructed comprehensive expressed gene profiles in the shell-forming tissues of the pearl oyster Pinctada fucata and identified novel shell formation-related genes candidates. Principal Findings: We employed the GS FLX 454 system and constructed transcriptome data sets from pallial mantle and pearl sac, which form the nacreous layer, and from t

Abstract The influence of shell body color on pearls has been studied extensively, but the effect of shell interference color selection on pearls has not been fully understood yet. Because interference color is an important factor determining pearl quality, it is important to study whether the shell interference color of the donor and recipient oysters has any influence on the resulting pearls' interference color to cope with the market demands. We report that selective breeding of red- and blue-line Pinctada fucata martensii pearl oysters produce high-quality pearls based on shape, flaw, color, size, and luster assessment categories. Saibo from red- and blue-line donors was implanted with a rounded nucleus into the red- and blue-line recipient oysters from the same batch in four treatments which we refer to as DRMR (red-donor, red-recipient), DRMB (red-donor, blue-recipient), DBMR (blue-donor, red-recipient), and DBMB (blue-donor, blue-recipient) oysters. Pearl shape and flaws, body yellowness index (YI) and interference value color categories, luster value, total nacre and tablet thickness, and surface microstructure for these treatments are reported. More DRMR pearls are high grade (H) than DBMB, DBMR, and DRMB pearls. Using electronic pearl quality measuring devices, DRMR pearls have the lowest YI and highest interference color values, rendering them superior in color category. Whole nacre thickness of pearls estimated by the SEM on the pearl section reveal DRMR pearls ha

Biological systems have a remarkable capability to produce perfect fine structures such as seashells, pearls, bones, teeth and corals. These structures are composites of interacting inorganic (calcium phosphate or carbonate minerals) and organic counterparts. It is difficult to say with certainty which part has the primary role. For example, the growth of molluscan shell crystals is thought to be initiated from a solution by the extracellular organic matrix (ECM). According to this theory, the matrix induces nucleation of calcium containing crystals. Recently, an alternative theory has been put forward, stating that a class of granulocytic hemocytes would be directly involved in shell crystal production in oysters. In the work presented here the surface of AISI 316 stainless steel was modified by deposition of ECM proteins. The ability of the modified substrates to induce nucleation and growth of hydroxyapatite (HA) from simulated body fluid (SBF) was examined by a kinetic study using two methods: (1) a simple soaking process in SBF and (2) a laser-liquid-solid interaction (LLSI) process which allows interaction between a scanning laser beam and a solid substrate immersed in SBF. The deposited HA layers were investigated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). It was found that a coating of stainless steel surface with native ECM proteins induced nucleation and growth of HA and facilitated its crystallization. By the process o

Turquoise nucleus cultivated (TNC) pearls represent a distinctive variety which are distinguished by their unique nucleus and remarkable aesthetic appeal. In contradistinction to the common pearls, which were formed by a shell nucleus, TNC pearls are characterized by a nucleus composed of a turquoise-like mineral. This study presents a comprehensive analysis of the spectral characteristics of TNC pearls. It reveals that TNC pearls grew in seawater, as indicated by the peak area ratio of Sr to Ca in X-ray fluorescence data. Additionally, the relatively subdued luster of TNC pearls is hypothesized to result from the specific nature of their nucleus material. It is noteworthy that the nuclei of these pearls are not composed of natural turquoise because their infrared spectrum exhibits characteristic absorption peaks of gibbsite at 1025 cm^-1 and 669 cm^-1, alongside peaks indicative of organic compounds. It is proposed that the nucleus consists of a gibbsite, encased within a protective layer of organic compounds during the carving process. In addition, three-dimensional (3D) fluorescence and photoluminescence spectroscopy demonstrate that the fluorescence characteristics of TNC pearls are comparable to those of traditional cultivated pearls. This study analyzes the samples derived from black-lipped oysters and golden-lipped oysters respectively. This finding underscores the efficacy of 3D fluorescence and photoluminescence spectroscopy as reliable methods for identifying these new pearl species.

century he began experiments to induce oysters to produce pearls. After twelve years of costly and discouraging … home certainly meant more than knowing how to produce pearls. Quitting now would be easy. All he had to … be a way to learn from nature how to make oysters produce absolutely round pearls. Dressed in coarse