Search results for "Oyster"

2017

The consequences of emerging marine diseases on the evolutionary trajectories of affected host populations in the marine realm are largely unexplored. Evolution in response to natural selection depends on the genetic variation of the traits under selection and the interaction of these traits with the environment (GxE). However, in the case of diseases, genotypes of pathogens add another dimension to this interaction. Therefore, the study of disease resistance needs to be extended to the interaction of host genotype, pathogen genotype and environment (GxGxE). In the present study we used a full-sib breeding design crossing two genetically differentiated populations of the Pacific oyster Cras…

Numerical Taxonomy of Aerobic, Gram-negative Bacteria associated with Oysters and Surrounding Seawater of the Mediterranean Coast

1995

Abstract A numerical taxonomic study was performed on 245 strains of heterotrophic, aerobic, marine bacteria, plus 26 reference strains. The isolates were obtained from oysters and seawater sampled monthly over one year, by direct plating on Marine Agar. The strains were characterised by 93 morphological, biochemical, physiological and nutritional tests. Clustering yielded 46 phena at 0.60 S level (S J coefficient). Some could be identified as species of Alteromonas, Shewanella, Deleya, Flavobacterium, Oceanospirillum, Pseudomonas and marine Agrobacterium -like organisms, others were unidentified groups. Several phena seem to correspond to as yet undescribed taxa.

Thermal stability of nacre proteins of the polynesian pearl oyster: a proteomic study.

2015

Mollusc shells are organic-inorganic composites that are often preserved in the fossil record. However, the way the organic fraction, also called shell matrix, gets fossilized remains an unsolved question, in spite of several old and more recent studies. In the present paper, we have tried to mimic a diagenetic process by constantly heating for ten days at 100°C fresh nacre powder samples of the Polynesian pearl oyster Pinctadamargaritifera. Each day, aliquots of nacre powder were sampled and the matrix was subsequently extracted. It was further analysed by direct weigh quantification, by immunological techniques and by proteomics. Our preliminary data suggest that nacre proteins, when heat…

Multi-isotopic and trace element evidence against different formation pathways for oyster microstructures

2021

Geochimica et cosmochimica acta 308, 326-352 (2021). doi:10.1016/j.gca.2021.06.012

Experimental and natural cathodoluminescence in the shell of Crassostrea gigas from Thau lagoon (France): ecological and environmental implications.

2006

We present a cathodoluminescence (CL) study of growth layer deposition in the shell of the oyster Crassostrea gigas. CL is based on the physical properties of lattice-bound manganese (Mn2+), which is the main activator in calcium carbonate. Our study involved chemical marking by immersing individuals in seawater to which manganese chloride had been added, and subsequent reading of the shell with CL microscopy coupled with numeric treatment of microphotographs; CL emission was analyzed using a scanning electron microscope coupled to a spectrometer. Since the marking did not harm the oysters, repeated markings were possible, allowing validation of the inferences made from analysis of the shel…

Pmarg-pearlin is a matrix protein involved in nacre framework formation in the pearl oyster Pinctada margaritifera.

2011

11 pages; International audience; The shell of pearl oysters is organized in multiple layers of CaCO(3) crystallites packed together in an organic matrix. Relationships between the components of the organic matrix and mechanisms of nacre formation currently constitute the main focus of research into biomineralization. In this study, we characterized the pearlin protein from the oyster Pinctada margaritifera (Pmarg); this shares structural features with other members of a matrix protein family, N14/N16/pearlin. Pmarg pearlin exhibits calcium- and chitin-binding properties. Pmarg pearlin transcripts are distinctively localized in the mineralizing tissue responsible for nacre formation. More s…

Characterization of molecular processes involved in the pearl formation in Pinctada margaritifera for the sustainable development of pearl farming in…

2011

11 pages; International audience

The ‘Shellome’ of the Crocus Clam Tridacna crocea Emphasizes Essential Components of Mollusk Shell Biomineralization

2021

Molluscan shells are among the most fascinating research objects because of their diverse morphologies and textures. The formation of these delicate biomineralized structures is a matrix-mediated process. A question that arises is what are the essential components required to build these exoskeletons. In order to understand the molecular mechanisms of molluscan shell formation, it is crucial to identify organic macromolecules in different shells from diverse taxa. In the case of bivalves, however, taxon sampling in previous shell proteomics studies are focused predominantly on representatives of the class Pteriomorphia such as pearl oysters, edible oysters and mussels. In this study, we hav…

Pearl grafting: tracking the biological origin of nuclei by straightforward immunological methods.

2018

9 pages; International audience; French Polynesia is renowned for the production of Tahitian black pearl. These gems are obtained by grafting a nucleus into the gonad of a receiving oyster together with a graft, i.e. a small section of mantle tissue of a donor oyster. This procedure initiates the formation of a pearl sack around the nucleus, and subsequently, the deposition of concentric layers of nacre. The nucleus plays a key-role in pearl formation and its characteristics influence markedly the quality of the final product. As it is manufactured from mollusc shells, it contains a small percentage of organics. In the present paper, we used a set of biochemical techniques to characterize a…

Effects of trophic and environmental conditions on the growth of Crassostrea gigas in culture

1997

In order to study the possibility of exploiting protected marine areas, comparative data on the cultivation of the oyster Cassostrea gigas in the South Tyrrenian Sea are reported. The oysters were cultured at -7 and - 13 m on long lines linked to artificial reefs. The observations, made during a 12-month period, were of the chemical-physical and trophic properties of the water column and growth rates of the oysters. Temperature ranged between 19.81 ± 4.67°C at -7 m and 18.03 ± 3.03°C at - 13 m. Salinity showed typical Mediterranean values. The area presented oligotrophic features: the chlorophyll-a (CHLa) concentration ranged between 0.05 ± 0.01 and 0.04 ± 0.02 μg 1-1 at -7 and -13 m, respe…