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1.
Open Biol ; 12(5): 210317, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35506205

RESUMO

Exosomes, a subset of small extracellular vesicles, carry various nucleic acids, proteins, lipids, amino acids and metabolites. They function as a mode of intercellular communication and molecular transfer. Exosome cargo molecules, including small non-coding RNAs (sncRNAs), are involved in the immune response in various organisms. However, the role of exosome-derived sncRNAs in immune responses in molluscs remains unclear. Here, we aimed to reveal the sncRNAs involved in the immune response during grafting transplantation by the pearl oyster Pinctada fucata. Exosomes were successfully extracted from the P. fucata haemolymph during graft transplantation. Abundant microRNAs (miRNAs) and PIWI-interacting RNAs (piRNAs) were simultaneously discovered in P. fucata exosomes by small RNA sequencing. The expression patterns of the miRNAs and piRNAs at the grafting and initial stages were not substantially different, but varied significantly between the initial and later stages. Target prediction and functional analysis indicate that these miRNAs and piRNAs are related to immune response upon grafting transplantation, whereas piRNAs may also be associated with transposon silencing by targeting with genome transposon elements. This work provides the basis for a functional understanding of exosome-derived sncRNAs and helps to gain further insight into the PIWI/piRNA pathway function outside of germline cells in molluscs.


Assuntos
Exossomos , MicroRNAs , Pinctada , Pequeno RNA não Traduzido , Animais , Exossomos/genética , Exossomos/metabolismo , Imunidade , MicroRNAs/genética , Pinctada/genética , Pinctada/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo
2.
Mar Pollut Bull ; 178: 113649, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35427816

RESUMO

This editorial presents results of the MANA (MANagement of Atolls) project compiled in the form of a Marine Pollution Bulletin collection of 14 articles. MANA is a project funded by the French Agence National pour la Recherche that specifically addresses the development of knowledge and management tools for pearl farming atolls, with a focus on the spat collecting activity in French Polynesia. The 14 papers cover the range of thematic tasks described in the initial project, including atoll geomorphology and bathymetry, climate forcing, atoll lagoon and rim hydrodynamics, typology of atolls, evaluation of remote sensing data for monitoring atoll lagoons, and development of numerical models and spatially-explicit tools that altogether have contributed to the applied objectives. In addition, this editorial draws an update on the pearl farming industry in French Polynesia with the latest statistics, and discusses the next targeted priorities for research programs focusing on pearl farming atolls.


Assuntos
Pinctada , Animais , Aquicultura/métodos , Oceano Pacífico , Polinésia
3.
Fish Shellfish Immunol ; 123: 521-527, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35364260

RESUMO

The globular C1q domain-containing (C1qDC) protein can recognize a variety of ligands, such as pathogen-associated molecular patterns, and plays an important role in the innate immune response. Our previous studies showed that a novel globular C1q domain-containing protein (PmC1qDC-1) is involved in the damage repair process of pearl oyster shells. However, the function of PmC1qDC-1 in pearl oyster innate immunity remains unknown. In the present study, the high-level structural analysis showed that PmC1qDC-1 was a spherical structure composed of 10 strands and was similar to the AiC1qDC-2 of bay scallop (Argopecten irradians). In situ hybridization indicated that PmC1qDC-1 had strong fluorescence signal in gills. Furthermore, the mRNA expression of PmC1qDC-1 was highly induced at 6-48 h in gill after lipopolysaccharide, peptidoglycan and polyinosinic-polycytidylic acid stimulation. Additionally, we obtained the recombinant protein of PmC1qDC-1 (rPmC1qDC-1) and found that rPmC1qDC-1 had antibacterial activity against Gram-negative (i.e., Pseudomonas aeruginosa, Vibrio parahaemolyticus, Escherichia coli, and Aeromonas hydrophila) and Gram-positive (i.e., Staphylococcus aureus and Bacillus subtilis) bacteria. These results indicated that PmC1qDC-1 might play an important role in the immune response against bacteria and viruses. This study provides clues for further studying the immune defense of Pinctada fucata martensii against pathogens and exploring the evolution of the classic pathway of complement system.


Assuntos
Pectinidae , Pinctada , Sequência de Aminoácidos , Animais , Complemento C1q/metabolismo , Imunidade Inata/genética , Proteínas Recombinantes/metabolismo
4.
Biofouling ; 38(2): 186-206, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35282730

RESUMO

Pinctada maxima are most well known for their production of high-quality natural pearls. They also generate another natural material, the byssus, an adhesive thread critical for steadfast attachment underwater. Herein, P. maxima byssal threads were analysed via proteotranscriptomics to reveal 49 proteins. Further characterisation was undertaken on five highly expressed genes: glycine-rich thread protein (GRT; also known as PUF3), apfp1/perlucin-like protein (Pmfp1); peroxidase; thrombospondin 1, and Balbiani ring 3 (BR3), which showed localised tissue expression. The spatial distribution of GRT and Pmfp1 via immunodetection combined with histology helped to identify glandular regions of the foot that contribute to byssal thread production: the byssal gland, the duct gland, and two thread-forming glands of basophilic and acidophilic serous-like cells. This work advanced primary knowledge on the glands involved in the creation of byssal threads and the protein composition of the byssus for P. maxima, providing a platform for the design of marine biopolymers.


Assuntos
Pinctada , Adesivos , Animais , Biofilmes , Biopolímeros , Pinctada/genética , Pinctada/metabolismo , Proteínas/genética , Proteínas/metabolismo
5.
Mar Biotechnol (NY) ; 24(2): 303-319, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35353261

RESUMO

As an important economic shellfish, the pearl oyster, Pinctada fucata, and its larvae are an ideal model for studying molecular mechanisms of larval development in invertebrates. Larval development directly affects the quantity and quality of pearl oysters. MicroRNAs (miRNAs) may play important roles in development, but the effects of miRNA expression on P. fucata early development remain unknown. In this study, miRNA and mRNA transcriptomics of seven different P. fucata developmental stages were analyzed using Illumina RNA sequencing. A total of 329 miRNAs, including 87 known miRNAs and 242 novel miRNAs, and 33,550 unigenes, including 26,333 known genes and 7217 predicted new genes, were identified in these stages. A cluster analysis showed that the difference in the numbers of miRNAs was greatest between fertilized eggs and trochophores. In addition, the integrated mRNA transcriptome was used to predict target genes for differentially expressed miRNAs between adjacent developmental stages, and the target genes were subjected to a gene ontology enrichment analysis. Using the gene ontology annotation, 100 different expressed genes and 95 differentially expressed miRNAs were identified as part of larval development regulation. Real-time PCR was used to identify eight mRNAs and three miRNAs related to larval development. The present findings will be helpful for further clarifying the regulatory mechanisms of miRNA in invertebrate larval development.


Assuntos
MicroRNAs , Pinctada , Animais , Perfilação da Expressão Gênica , MicroRNAs/genética , MicroRNAs/metabolismo , Anotação de Sequência Molecular , Pinctada/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transcriptoma
6.
Mar Pollut Bull ; 176: 113472, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35219077

RESUMO

Oyster farming for black pearl production is central in French Polynesia. It is the second source of national income and provides substantial job opportunities, notably in remote atolls. However, this sector has been undermined by successive crises, such as mass-mortalities of wild and farmed oyster stocks that have impacted entire lagoons. An option to revive the activity consists of reintroducing oysters in strategic benthic locations selected to maximize reproduction and dispersal of larvae throughout the lagoon, hence promoting recolonization and spat collection for farming. For Takaroa, a Tuamotu atoll recently impacted by mortalities, a systematic prioritization approach identified these restocking sites, using environmental and socio-economic criteria such as: location of suitable habitats for oyster settlement, larval connectivity estimated from hydrodynamic circulation model, farming waste accumulation, and opportunity cost to fishers and farmers who lose access to restocking areas. This approach provides managers with a portfolio of restocking options.


Assuntos
Pinctada , Agricultura , Animais , Aquicultura , Ecossistema , Hidrodinâmica , Polinésia
7.
Gene ; 821: 146285, 2022 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-35176427

RESUMO

KCNQ1, a voltage-gated potassium ion channel, plays an important role in various physiological processes, including osteoblast differentiation in higher animals. However, its function in lower invertebrates such as marine shellfish remains poorly understood. Pearl oysters, such as P. fucata martensii, are ideal for studying biomineralisation. In this study, a full-length cDNA of KCNQ1 from P. fucata martensii (PfKCNQ1) was obtained, and its function in shell formation was investigated. The full-length 3945 bp cDNA of PfKCNQ1 included an open reading frame (ORF) of 1944 bp encoding a polypeptide of 647 amino acids. Multiple sequence alignment revealed high homology with KCNQ1 from other species, with six transmembrane domains (S1 - S6) and a pore (P) region. Expression pattern analysis showed that PfKCNQ1 was expressed in all tested tissues, with highest expression in mantle and heart, and shell notching induced PfKCNQ1 expression. Silencing PfKCNQ1 expression inhibited PfKCNQ1 expression and downregulated four biomineralisation-related genes (Shematrin, Pif80, N16 and MSI60). Disordered crystals or "hollows" were visible in the shell ultrastructure by scanning electron microscopy following PfKCNQ1 knockdown. The results suggested that PfKCNQ1 may participate in or regulate biomineralisation and shell formation in pearl oyster.


Assuntos
Clonagem Molecular/métodos , Canal de Potássio KCNQ1/genética , Canal de Potássio KCNQ1/metabolismo , Nácar/metabolismo , Pinctada/metabolismo , Sequência de Aminoácidos , Exoesqueleto/metabolismo , Animais , Canal de Potássio KCNQ1/química , Fases de Leitura Aberta , Pinctada/genética , Domínios Proteicos , Alinhamento de Sequência , Distribuição Tecidual
8.
Gene ; 823: 146367, 2022 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-35202732

RESUMO

To understand the molecular responses of Pinctada fucata with different shell colors to salinity stress, we used transcriptome sequencing on the mantle of P. fucata with a black shell and red shell color under the salinity of 20, 35, and 50. The 414 and 2371 differentially expressed genes (DEGs) in P. fucata with a black shell under low- or high-salt stress, while there were 588 and 3009 DEGs in P. fucata with a red shell. KEGG pathway enrichment analysis showed that, under low salt stress, the DEGs of P. fucata with the black shell were significantly enriched in pathways MAPK signaling pathway, protein processing in endoplasmic reticulum, vitamin B6 metabolism, longevity regulating pathway-multiple species, estrogen signaling pathway and antigen processing and presentation, the DEGs of P. fucata with a red shell were significantly enriched in pathways vitamin B6 metabolism. Under high salt stress, the DEGs of P. fucata with a red shell were significantly enriched in pathways arginine biosynthesis. 11 DEGs were randomly selected for quantitative real-time PCR, and the results were consistent with the RNA-seq. In addition, under high salt stress, DEGs were enriched into some pathways related to osmotic regulation and immune defense of P. fucata with black shell and red shell, such as Glycolysis / Gluconeogenesis, AMPK signaling pathway, Beta-Alanine metabolism, Glycine, serine and threonine metabolism, MAPK signaling pathway and Phagosome. The study showed that high salt stress had a greater influence on P. fucata with two shell colors, and P. fucata with a black shell made a positive immune defense response. Our results will improve to further understand the salt tolerance mechanism of P. fucata with different shell colors.


Assuntos
Perfilação da Expressão Gênica/veterinária , Redes Reguladoras de Genes , Pinctada/anatomia & histologia , Exoesqueleto/anatomia & histologia , Exoesqueleto/química , Animais , Cor , Regulação da Expressão Gênica , Pinctada/genética , RNA-Seq , Estresse Salino
9.
Fish Shellfish Immunol ; 123: 10-19, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35182724

RESUMO

Pre-grafting condition is an important method to promote recovery from transplant surgery during pearl production. In the present study, we constructed two DNA methylomes from pearl oysters with and without conditioning to investigate the molecular mechanism of the pearl oyster Pinctada fucata martensii underlying the pre-grafting condition. A total of 4,594,997 and 4,930,813 methyl CG in the control (Con) and pre-grafting group (PT) were detected, resulting in the whole genome methylation profile and methylation pattern in P. f. martensii. Results reveal that the promoter, especially the CpG island-rich region, was more infrequently methylated than the gene function elements in P. f. martensii. A total of 51,957 differently methylated regions (DMRs) between Con and PT were obtained, including 3789 DMR in the promoter and 16,021 in the gene body. Based on gene ontology and pathway enrichment analyses, these DMRs were mainly related to "cellular process", "metabolic process", "Epstein-Barr virus infection", and "Fanconi anemia pathway". The methylation site in the promoter region may be associated with the promoter activity and transcription factor binding. These results help our understanding of the mechanism of pre-grafting condition, thereby providing key information in guiding to improve the conditioning methods for enhanced pearl oyster survival rate after transplantation.


Assuntos
Infecções por Vírus Epstein-Barr , Pinctada , Animais , Metilação de DNA , Infecções por Vírus Epstein-Barr/genética , Herpesvirus Humano 4/genética , Pinctada/genética , Pinctada/metabolismo , Sulfitos , Transcriptoma
10.
Acta Biomater ; 142: 194-207, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35041900

RESUMO

Biomineralization integrates complex physical and chemical processes bio-controlled by the living organisms through ionic concentration regulation and organic molecules production. It allows tuning the structural, optical and mechanical properties of hard tissues during ambient-condition crystallisation, motivating a deeper understanding of the underlying processes. By combining state-of-the-art optical and X-ray microscopy methods, we investigated early-mineralized calcareous units from two bivalve species, Pinctada margaritifera and Pinna nobilis, revealing chemical and crystallographic structural insights. In these calcite units, we observed ring-like structural features correlated with a lack of calcite and an increase of amorphous calcium carbonate and proteins contents. The rings also correspond to a larger crystalline disorder and a larger strain level. Based on these observations, we propose a temporal biomineralization cycle, initiated by the production of an amorphous precursor layer, which further crystallizes with a transition front progressing radially from the unit centre, while the organics are expelled towards the prism edge. Simultaneously, along the shell thickness, the growth occurs following a layer-by-layer mode. These findings open biomimetic perspectives for the design of refined crystalline materials. STATEMENT OF SIGNIFICANCE: Calcareous biominerals are amongst the most present forms of biominerals. They exhibit astonishing structural, optical and mechanical properties while being formed at ambient synthesis conditions from ubiquitous ions, motivating the deep understanding of biomineralization. Here, we unveil the first formation steps involved in the biomineralization cycle of prismatic units of two bivalve species by applying a new multi-modal non-destructive characterization approach, sensitive to chemical and crystalline properties. The observations of structural features in mineralized units of different ages allowed the derivation of a temporal sequence for prism biomineralization, involving an amorphous precursor, a radial crystallisation front and a layer-by-layer sequence. Beyond these chemical and physical findings, the herein introduced multi-modal approach is highly relevant to other biominerals and bio-inspired studies.


Assuntos
Bivalves , Pinctada , Animais , Carbonato de Cálcio/química , Cristalização , Proteínas
11.
Fish Shellfish Immunol ; 121: 74-85, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34990804

RESUMO

Implantation of a spherical nucleus into a recipient oyster is a critical step in artificial pearl production. However, the molecular mechanisms underlying the response of the pearl oyster to this operation are poorly understood. In this research, we used transcriptomic and proteomic analyses to examine allograft-induced changes in gene/protein expression patterns in Pinctada fucata martensii 12 h after nucleus implantation. Transcriptome analysis identified 688 differential expression genes (DEGs) (FDR<0.01 and |fold change) > 2). Using a 1.2-fold increase or decrease in protein expression as a benchmark for differentially expressed proteins (DEPs), 108 DEPs were reliably quantified, including 71 up-regulated proteins (DUPs) and 37 down-regulated proteins (DDPs). Further analysis revealed that the GO terms, including "cellular process", "biological regulation" and "metabolic process" were considerably enriched. In addition, the transcriptomics analysis showed that "Neuroactive ligand-receptor interaction", "NF-kappa B signaling pathway", "MAPK signaling pathway", "PI3K-Akt signaling pathway', "Toll-like receptor signaling pathway", and "Notch signaling pathway" were significantly enriched in DEGs. The proteomics analysis showed that "ECM-receptor interaction", "Human papillomavirus infection", and "PI3K-Akt signaling pathway" were significantly enriched in DEPs. The results indicate that these functions could play an important role in response to pear oyster stress at nucleus implantation. To assess the potential relevance of quantitative information between mRNA and proteins, using Ward's hierarchical clustering analysis clustered the protein/gene expression patterns across the experimental and control samples into six groups. To investigate the biological processes associated with the protein in each cluster, we identified the significantly enriched GO terms and KEGG pathways in the proteins in each cluster. Gene set enrichment analysis (GSEA) was used to reveal the potential protein or transcription pathways associated with the response to nuclear implantation. Thus, the study of P. f. martensii is essential to enhance our understanding of the molecular mechanisms involved in pearl biosynthesis and the biology of bivalve molluscs.


Assuntos
Pinctada , Proteômica , Estresse Fisiológico , Transcriptoma , Animais , Fosfatidilinositol 3-Quinases , Pinctada/genética , Proteínas Proto-Oncogênicas c-akt , Transdução de Sinais
12.
Fish Shellfish Immunol ; 121: 116-123, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34995768

RESUMO

Molluscan bivalves secrete shell matrices into the extrapallial space (EPS) to guide the precipitation of rigid shells. Meanwhile, immune components are present in the EPS and shell matrices, which are pivotal in resistant to invaded pathogens, thus ensuring the shell formation process. However, the origin of these components remains unclear. In this study, we revealed numerous vesicles were secreted from the outer mantle epithelial cells by using light and electron microscopes. The secreted vesicles were isolated by gradient centrifugation and confirmed by transmission electron microscopy. Proteomics analysis showed that the secreted vesicles were composed of cytoplasmic and immune components, most of which do not have signal peptides, indicating that they were secreted by a non-classical pathway. Moreover, real-time PCR revealed that some immune components were highly expressed in the mantle tissue, compared to the hemocytes. FTIR analysis verified the presence of lipids in the shell matrices, indicating that the vesicles have integrated into the shell layers. Taken together, our results suggested that mantle epithelial cells secreted some important immune components into the EPS via secreted vesicle transportation, thus cooperating with the hemocytes to play a vital role in immunity during shell formation.


Assuntos
Exoesqueleto , Vesículas Extracelulares , Pinctada , Exoesqueleto/imunologia , Animais , Vesículas Extracelulares/imunologia , Hemócitos/imunologia , Microscopia Eletrônica de Transmissão , Pinctada/imunologia , Reação em Cadeia da Polimerase em Tempo Real
13.
Chem Biodivers ; 19(3): e202100876, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35098641

RESUMO

Although the effect of pearl powder has been recognized for more than a thousand years from healthcare to beauty care, there has yet to be an in-depth understanding of its anti-photoaging effect. In the present study, the protective effect of pearl extract (PE) on UV-induced photoaging in mice was evaluated. First, the amino acid analysis of PE was carried out. Then, different dosages of pearl extract gel (PEG) were applied topically on the shaved dorsal skins regions of mice before UV irradiation. Skin physiological and histological analysis, antioxidant enzymes and inflammatory factor test were used to evaluate the anti-photoaging effect of PEG. The results showed that PEG contained 14 amino acids, and could inhibit UV-irritated skin wrinkles, laxity, thickness, and dryness. Moreover, PEG upregulated the activities of CAT, GSH-Px, SOD and decreased MDA level, and suppressed the production of IL-1ß, IL-6, PGE2 , TNF-α, and COX-2 in UV-irradiated mice. The therapeutic effect in high dose PEG group was superior to those of positive control (Vitamin E). This study demonstrated the underlying mechanisms of PEG against UV-irritated photoaging. And PEG possesses a potential use in photoprotective medicines and cosmetics.


Assuntos
Pinctada , Envelhecimento da Pele , Animais , Carbonato de Cálcio , Camundongos , Extratos Vegetais/metabolismo , Extratos Vegetais/farmacologia , Pele , Raios Ultravioleta/efeitos adversos
14.
J Nat Med ; 76(2): 419-434, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35044595

RESUMO

Shells are composed of two types of calcium carbonate polymorphs-the prismatic layer and the nacreous layer. Pearls, composed of the nacreous layer, have been used in Chinese medicine since ancient times. We have previously shown that extracts from the nacreous layer improves scopolamine-induced memory impairment. However, whether pearl ameliorates cognitive disorders induced by amyloid-ß 1-40 (Aß1-40) has not been elucidated. In this study, we investigated whether nacre extract improves memory impairment induced by intracerebroventricular injection of Aß1-40. Administration of nacre extract led to recovery from Aß1-40-induced impairments in object recognition, short-term memory, and spatial memory. Nacre extract reversed the increase in lipid peroxidation caused by Aß1-40 in the cerebral cortex by increasing the expression of catalase and superoxide dismutase. In addition, nacre extract recovered the expression and phosphorylation of cyclic AMP response element-binding protein (CREB), which decreased with Aß1-40 treatment, and increased the expression of brain-derived neurotrophic factor and neuropeptide Y, which are regulated by CREB. Nacre extract also suppressed acetylcholine esterase activity and Aß1-40-induced tau phosphorylation. Histochemical analysis of the hippocampus region showed that the nacre extract protected against Aß1-40-induced neuronal loss in the hippocampus. These results suggest that nacre extract protects against Aß1-40-induced neuronal cell death by suppressing oxidative stress and increasing the expression and phosphorylation of CREB.


Assuntos
Nácar , Pinctada , Peptídeos beta-Amiloides/metabolismo , Animais , Hipocampo/metabolismo , Transtornos da Memória/induzido quimicamente , Transtornos da Memória/tratamento farmacológico , Transtornos da Memória/metabolismo , Nácar/metabolismo , Pinctada/metabolismo , Extratos Vegetais/farmacologia
15.
Sci Total Environ ; 810: 151189, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34757105

RESUMO

Marine heatwaves (MHWs) are weather-timescale extreme events in the oceans and can have devastating effects on marine bivalves and ecosystems they support, with considerable socio-economic consequences. Yet, the extent to which marine bivalves have the capacity to acclimate and adapt to MHWs remains unknown. Understanding molecular responses to MHWs is imperative to develop strategies for conservation of ecologically and economically important marine organisms. Here, using RNA-Seq, we investigate how various MHWs scenarios elicit molecular changes in threatened and vulnerable pearl oysters, Pinctada maxima (Jameson). Acute exposure of MHWs - mimicked by rapid increases of seawater temperature from 24 °C to 28 °C and 32 °C, respectively - significantly affected the expression levels of metabolic and immune-related genes, with thermal stress-responsive genes especially like HSP20, HSP70 and HSP90 being remarkably up-regulated. Following repeat exposure to MHWs, encouragingly, pearl oysters exhibited evident acclimation responses, as best exemplified by significantly lowered expression levels of key stress-responsive genes involved in metabolism and immunity in comparison to those observed during acute exposure. Findings of the present study provide a better understanding of molecular processes underpinning the acclimation and adaptation of marine bivalves to MHWs in the context of climate change.


Assuntos
Pinctada , Aclimatação , Animais , Ecossistema , Perfilação da Expressão Gênica , Oceanos e Mares , Transcriptoma
16.
Environ Pollut ; 293: 118522, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34793903

RESUMO

Microplastics are extremely widespread aquatic pollutants that severely detriment marine life. In this study, the influence of microplastics on biomineralization was investigated. For the first time, multiple forms and types of microplastics were detected and isolated from the shells and pearls of Pinctada fucata. According to the present study, the abundance of microplastics in shells and pearls was estimated at 1.95 ± 1.43 items/g and 0.53 ± 0.37 items/g respectively. Interestingly, microplastics were less abundant in high-quality round pearls. Microplastics may hinder the growth of calcite and aragonite crystals, which are crucial components required for shell formation. During the process of biomineralization microplastics became embedded in shells, suggesting the existence of a novel pathway by which microplastics accumulate in bivalves. After a 96-h exposure to microplastics, the expression level of typical biomineralization-related genes increased, including amorphous calcium carbonate binding protein (ACCBP) gene which experienced a significant increase. ACCBP promotes the formation of amorphous calcium carbonate (ACC), which is the pivotal precursor of shell formation-related biominerals. ACCBP is highly expressed during the developmental stage of juvenile oysters and the shell-damage repair process. The increased expression of ACCBP suggests biomineralization is enhanced as a result of microplastics exposure. These results provide important evidence that microplastics exposure may impact the appearance of biominerals and the expression of biomineralization-related genes, posing a new potential threat to aquatic organisms.


Assuntos
Pinctada , Exoesqueleto , Animais , Biomineralização , Carbonato de Cálcio , Microplásticos , Pinctada/genética , Plásticos
17.
J Steroid Biochem Mol Biol ; 217: 106045, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34915168

RESUMO

Ecdysone exists in arthropods, Mollusca and other invertebrates and plays vital roles in exoskeleton formation of Ecdysozoa. However, little is known about its functions in bivalve species. Herein, we identified ecdysone from the serum of pearl oyster Pinctada fucata martensii and obtained the coding sequence of ecdysone receptor (PmEcR) and homologue of its heterodimer protein retinoid X receptor (PmRXR). The deduced amino acid sequences of PmEcR and PmRXR contained a DNA-binding and ligand-binding domain and were very similar to the orthologs of other species. Moreover, PmEcR and PmRXR were located in the nuclei and cytoplasm of HEK-293T cells. PmEcR and PmRXR were highly expressed in early embryos and biomineralized mantle tissue. Moreover, the serum concentration of ecdysone significantly increased at 2, 4, 6, and 8 h post-shell notching. The expression of PmEcR in the mantle tissue was significantly induced at the corresponding time points, while that of PmRXR was significantly induced at 6 h. Ecdysone stimulation remarkably induced the expression of growth factors (BMP2 and BMP7), transcription factors (PmRunt and AP-1), and shell matrix protein genes (chitinase, lysine-rich matrix protein (KRMP), TYR2, and PmCOLVI), which indicated that ecdysone signaling plays important roles in shell repair. However, yeast two-hybrid assay and bimolecular fluorescence complementation showed that PmEcR and PmRXR did not form dimers, suggesting the different molecular interactions of EcR in bivalves. These findings provide insights into the function of ecdysone and its regulation pathway in bivalve species.


Assuntos
Pinctada , Sequência de Aminoácidos , Animais , Ecdisona/metabolismo , Pinctada/genética , Pinctada/metabolismo , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
18.
Technol Cult ; 62(4): 1032-1062, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34690158

RESUMO

This article traces the making of a techno-legal apparatus to regulate a new object: the "cultured" pearl. In the early 1920s, round pearls cultivated on Japanese farms provoked alarm within the Paris association whose members traded more pearls than anywhere in Europe. Despite their claims to be connoisseurs of surfaces, anti-cultivation pearl dealers in Paris asserted that a pearl's identity could only be ascertained by examining its inner structure. By mid-decade, dedicated pearl testing laboratories appeared and supported French court rulings about what to call the products of Japanese pearl cultivation in relation to "natural" pearls. The meanings of nature and culture were not fixed, but transformed in the 1920s, amid legal and technical efforts to know la perle japonaise inside out.


Assuntos
Liliaceae , Melanthiaceae , Pinctada , Animais , Europa (Continente) , Paris , Pinctada/fisiologia
19.
Aquat Toxicol ; 239: 105959, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34500377

RESUMO

In an era of unprecedented climate change, marine heatwaves (MHWs) are projected to increase in frequency, intensity, and duration, severely affecting marine organisms and fisheries and causing profound ecological and socioeconomic impacts. However, very little is known about effects of MHWs on ecologically and economically important bivalve species. Here, we investigate how pearl oysters, Pinctada maxima (Jameson), respond to MHWs under various simulated scenarios. Acute 3-day exposure to MHWs, mimicked by increasing the ambient seawater temperature from 24°C to 28°C, 32°C, and 36°C, respectively, induced significant changes (initially sustained increase and late decrease) in activities of antioxidant enzymes (GSH-Px, SOD, CAT, MDA, and T-AOC) and biomineralizaiton-related enzymes (AKP and ACP). Likewise, energy-metabolizing enzymes (NKA, CMA, and T-ATP) showed remarkable acute responses, with significant increases occurring at the beginning and end of thermal exposure. Following repeated exposure to MHWs, without exception, acute responses of assayed enzymes to MHWs were significantly alleviated, implying that pearl oysters have the ability to implement more efficient and less costly energy-utilizing strategies to compensate for thermal stress induced physiological interferences. These findings indicate that marine bivalves can respond plastically and acclimate rapidly to MHWs and pave the way for predicting the fate of this important taxonomic groups in rapidly changing oceans.


Assuntos
Pinctada , Poluentes Químicos da Água , Animais , Mudança Climática , Oceanos e Mares , Água do Mar , Poluentes Químicos da Água/toxicidade
20.
Mar Pollut Bull ; 173(Pt A): 112932, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34534933

RESUMO

Marine heatwaves (MHWs) have occurred with increasing duration, frequency and intensity in the past decade in the South China Sea, posing serious threats to marine ecosystems and fisheries. However, the impact of MHWs on marine bivalves - one of the most ecologically and economically important fauna in coastal ecosystems - remains largely unknown. Here, we investigated physiological responses of the pearl oyster, Pinctada maxima inhabiting a newly identified climate change hotspot (Beibu Gulf, South China Sea) to short-lasting and repeatedly-occurring MHWs scenarios. Following 3-day exposure to short-lasting MHWs scenarios with water temperature rapidly arising from 24 °C to 28 °C, 32 °C and 36 °C, respectively, mortality rates of pearl oysters increased, and especially they suffered 100% mortality at 36 °C. Activities of enzymes including acid phosphatase (ACP), alkaline phosphatase (AKP), glutathione (GSH) and level of malondialdehyde (MDA) increased significantly with increasing intensity and duration of MHWs, indicating thermal stress responses. When exposed to repeatedly-occurring MHWs scenarios, mortality rates of pearl oysters increased slightly, and thermal stress responses were alleviated, as exemplified by significant decreases in ACP, AKP, GSH and MDA activities compared with those during short-lasting MHWs scenarios, demonstrating the potential of P. maxima to acclimate rapidly to MHWs. These findings advance our understanding of how marine bivalves respond to MHWs scenarios varying in duration, frequency, and intensity.


Assuntos
Pinctada , Animais , Mudança Climática , Ecossistema , Pesqueiros , Temperatura
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