Ark Shell Research Articles

Accumulation of Polychlorinated Biphenyls and Their Effects on Antioxidant Enzyme Activities in Tissues of the Ark Shell (Anadara kagoshimensis)

Accumulation of Polychlorinated Biphenyls and Their Effects on Antioxidant Enzyme Activities in Tissues of the Ark Shell (Anadara kagoshimensis)

A chromosome-level genome assembly of the disco clam, Ctenoides ales.

The bivalve subclass Pteriomorphia, which includes the economically important scallops, oysters, mussels, and ark clams, exhibits extreme ecological, morphological, and behavioral diversity. Among this diversity are five morphologically distinct eye types, making Pteriomorphia an excellent setting to explore the molecular basis for the evolution of novel traits. Of pteriomorphian bivalves, Limida is the only order lacking genomic resources, greatly limiting the potential phylogenomic analyses related to eyes and phototransduction. Here, we present a limid genome assembly, the disco clam, Ctenoides ales (C. ales), which is characterized by invaginated eyes, exceptionally long tentacles, and a flashing light display. This genome assembly was constructed with PacBio long reads and Dovetail Omni-CTM proximity-ligation sequencing. The final assembly is ∼2.3Gb and over 99% of the total length is contained in 18 pseudomolecule scaffolds. We annotated 41,064 protein coding genes and reported a BUSCO completeness of 91.9% for metazoa_obd10. Additionally, we report a complete and annotated mitochondrial genome, which also had been lacking from Limida. The ∼20Kb mitogenome has 12 protein coding genes, 22 tRNAs, 2 rRNA genes, and a 1,589 bp duplicated sequence containing the origin of replication. The C. ales nuclear genome size is substantially larger than other pteriomorphian genomes, mainly accounted for by transposable element sequences. We inventoried the genome for opsins, the signaling proteins that initiate phototransduction, and found that, unlike its closest eyed-relatives, the scallops, C. ales lacks duplication of the rhabdomeric Gq-protein-coupled opsin that is typically used for invertebrate vision. In fact, C. ales has uncharacteristically few opsins relative to the other pteriomorphian families, all of which have unique expansions of xenopsins, a recently discovered opsin subfamily. This chromosome-level assembly, along with the mitogenome, is a valuable resource for comparative genomics and phylogenetics in bivalves and particularly for the understudied but charismatic limids.

Two peptides LLRLTDL and GYALPCDCL inhibit foam cell formation through activating PPAR-γ/LXR-α signaling pathway in oxLDL-treated RAW264.7 macrophages.

Foam cell formation plays a pivotal role in atherosclerosis-associated cardiovascular diseases. Bioactive peptides generated from marine sources have been found to provide multifunctional health advantages. In the present study, we investigated the anti-atherosclerotic effects of LLRLTDL (Bu1) and GYALPCDCL (Bu2) peptides, isolated from ark shell protein hydrolysates by assessing their inhibitory effect on oxidized LDL (oxLDL)-induced foam cell formation. The two peptides showed a promising anti-atherosclerotic effect by inhibiting foam cell formation, which was evidenced by inhibiting lipid accumulation in oxLDL-treated RAW264.7 macrophages and oxLDL-treated primary human aortic smooth muscle cells (HASMC). Two peptides effectively reduced total cholesterol, free cholesterol, cholesterol ester, and triglyceride levels by upregulating cholesterol efflux and downregulating cholesterol influx. Expression of cholesterol influx-related proteins such as SR-A1 and CD36 were reduced, whereas cholesterol efflux-related proteins such as ATP-binding cassette transporter ABCA-1 and ABCG-1 were highly expressed. In addition, Bu1 and Bu2 peptides increased PPAR-γ and LXR-α expression. However, PPAR-γ siRNA transfection reversed the foam cell formation inhibitory activity of Bu1 and Bu2 peptides. Furthermore, the synergistic effect of Bu1 and Bu2 peptides on foam cell formation inhibition was observed with PPAR-γ agonist thiazolidinediones, indicating that PPAR-γ signaling pathway plays a key role in foam cell formation of macrophages. Beyond their impact on foam cell formation, Bu1 and Bu2 peptides demonstrated anti-inflammatory potential by inhibiting the generation of pro-inflammatory cytokines and nitric oxide and NF-κB nuclear activation. Taken together, these results suggest that Bu1 and Bu2 peptides may be useful for atherosclerosis and associated anti-inflammatory therapies.

Development of a two-dimensional LC-MS/MS system for the determination of proline and 4-hydroxyproline enantiomers in biological and food samples.

A two-dimensional LC-MS/MS system has been developed for the enantioselective determination of proline (Pro), cis-4-hydroxyproline (cis-4-Hyp) and trans-4-hydroxyproline (trans-4-Hyp) in a variety of biological samples. The amino acids were pre-column derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F), and the NBD-derivatives were separated by a reversed-phase column (Singularity RP18) as their D plus L mixtures in the first dimension. The collected target fractions were then introduced into the second dimension where the enantiomers were separated by a Pirkle-type enantioselective column (Singularity CSP-001S) and determined by a tandem mass spectrometer (Triple Quad™ 5500). The method was validated by the standard amino acids and also by human plasma, and sufficient results were obtained for the calibration, precision and accuracy. The method was applied to human plasma and urine, bivalve tissues and fermented food/beverages. D-Pro was widely found in the human physiological fluids, bivalves and several fermented products. Although trans-4-D-Hyp was not found in all the tested samples, cis-4-D-Hyp was present in human urine and tissues of the ark shell, and further studies focusing on the origin and physiological significance of these D-enantiomers are expected.

Deep learning-based phenotype classification of three ark shells: Anadara kagoshimensis, Tegillarca granosa, and Anadara broughtonii

The rapid and accurate classification of aquatic products is crucial for ensuring food safety, production efficiency, and economic benefits. However, traditional manual methods for classifying ark shell species based on phenotype are time-consuming and inefficient, especially during peak seasons when the demand is high and labor is scarce. This study aimed to develop a deep learning model for the automated identification and classification of commercially important three ark shells (Tegillarca granosa, Anadara broughtonii, and Anadara kagoshimensis) from images. The ark shells were collected and identified using a polymerase chain reaction method developed in a previous study, and a total of 1,400 images were categorized into three species. Three convolutional neural network (CNN) models, Visual Geometry Group Network (VGGnet), Inception-Residual Network (ResNet), and SqueezeNet, were then applied to two different classification sets, Set-1 (four bivalve species) and Set-2 (three ark shell species). Our results showed that SqueezeNet demonstrated the highest accuracy during the training phase for both classification sets, whereas Inception-ResNet exhibited superior accuracy during the validation phase. Similar results were obtained after developing a third classification set (Set-3) to classify six categories by combining Set-1 and Set-2. Overall, the developed CNN-based classification model exhibited a performance comparable or superior to that presented in previous studies and can provide a theoretical basis for bivalve classification, thereby contributing to improved food safety, production efficiency, and economic benefits in the aquatic products industry.

Tribo‐performance assessment of brake friction composites prepared from agro‐industrial‐sea wastes using pin‐on‐disc

AbstractIn this work, eco‐friendly brake friction composites were developed using walnut shell powder‐fly ash‐white ark shell powder (agro‐industrial‐sea waste). The waste materials content in the friction composites varied from 33 to 53 wt% including a fixed content of fly ash (30 wt%) and walnut shell powder (3 wt%) and a varying amount of white ark shell powder (WASP) from 0 to 20 wt% with a step of 5 wt%. The fabricated specimens were characterized for tribo‐performance and compared with commercial brake lining specimen (CBLS) in compliance with ASTM G99 standards using pin‐on‐disc test setup under dry conditions. The specimens were tested for the disc speed varying from 500 to 2000 rpm under 50 and 150 N of normal loads. The friction coefficients and volume loss of the fabricated specimens were found insensitive to the compositional changes and highly sensitive to the normal load and disc speeds. SEM‐EDS analysis showed the frequent formation of friction films at higher disc speed and integration and disintegration of contact plateaus responsible for the changes in the friction and wear behavior. The direct comparison between the friction coefficient and volume loss indicated that 10 wt% of WASP in compensation with BaSO4 may be used to develop the brake friction composite.Highlights Brake friction composites prepared from the waste materials offered μ‐values from 0.31 to 0.6 in comparison with the CBLS. Friction coefficient dropped significantly at higher disc speed. Morphological and elemental analysis supported in estimating the probable friction and wear mechanisms.

Contamination Status and Risk Assessment of Paralytic Shellfish Toxins in Shellfish along the Coastal Areas of China.

Paralytic shellfish toxins (PSTs) are widely distributed in shellfish along the coast of China, causing a serious threat to consumer health; however, there is still a lack of large-scale systematic investigations and risk assessments. Herein, 641 shellfish samples were collected from March to November 2020, and the PSTs' toxicity was detected via liquid chromatography-tandem mass spectrometry. Furthermore, the contamination status and potential dietary risks of PSTs were discussed. PSTs were detected in 241 shellfish samples with a detection rate of 37.60%. The average PST toxicities in mussels and ark shells were considerably higher than those in other shellfish. The PSTs mainly included N-sulfonylcarbamoyl toxins (class C) and carbamoyl toxins (class GTX), and the highest PST toxicity was 546.09 μg STX eq. kg-1. The PST toxicity in spring was significantly higher than those in summer and autumn (p < 0.05). Hebei Province had the highest average PST toxicity in spring. An acute exposure assessment showed that consumers in Hebei Province had a higher dietary risk, with mussels posing a significantly higher dietary risk to consumers. This research provides reference for the green and sustainable development of the shellfish industry and the establishment of a shellfish toxin prevention and control system.

First report of Perkinsus olseni infections in blood cockles Tegillarca granosa on the south coast of Korea

The protozoan parasite Perkinsus olseni has become a focus of attention since it has been responsible for mass mortalities and economic losses in a wide range of bivalve hosts globally. The P. olseni host range along the south coast of Korea may extend beyond what was previously understood, and blood cockles in the Family Arcidae are also suggested to be potential hosts of P. olseni. In the present study, we applied histology and molecular techniques to identify Perkinsus sp. infections in the blood cockles Tegillarca granosa, which have been commercially exploited on the south coast of Korea for several decades. Histology and molecular techniques, including genus-specific immunofluorescence assay, species-specific fluorescence in situ hybridization, and phylogeny based on the ribosomal DNA internal transcribed spacer region revealed that T. granosa is infected by P. olseni, although the prevalence was low (0.5%). Histology revealed massive hemocyte infiltrations in the mantle, gill, and digestive gland connective tissues, indicating that the infection exerts negative impacts on the host cockles.

Genome-wide SNP-based diversity analysis and phylogeographic inference in the ark shell (Anadara broughtonii)

The ark shell (Anadara broughtonii) is a marine bivalve inhabiting the West Pacific coasts. Its natural resources have declined considerably in recent years due to overexploitation. Understanding of the genetic diversity and population structure of A. broughtonii is important for conservation and species-specific management. The Specific-Locus Amplified Fragment Sequencing (SLAF-seq) method was used to screen the SNPs for exploring the genetic diversity and phylogeographic characterization in 40 Anadara broughtonii individuals, 10 each from 4 sample locations: China, Japan, Korea, and Russia. We generated 394,768 SLAFs and developed 452,144 polymorphic SNPs. The observed and expected heterozygosity (Ho and He) ranged from 0.1805 to 0.3216 and from 0.1504 to 0.2156, respectively. Relatively strong differentiation was detected between populations from China/Russia and those from Japan/Korea, possibly related to the barrier effects from the Shandong Peninsula and the Korean Peninsula. Phylogenetic and Discriminant analysis of principal components (DAPC) supported the 40 individuals were mainly classified into four genetically distinct groups according to their sampling locations. Overall, Japanese and Korean populations owned higher genetic diversity. However, the two native populations may probably be affected by human activities such as artificial culture and commercial transportation. In order to avoid the further admixture of the native population of A. broughtonii, more attention should be paid to the germplasm resources protection of this species. Our results demonstrated the capability and high resolution of SNPs derived from SLAF-seq to measure the population genetic diversity and phylogeographic structure of A. broughtonii.

Utility of a modified lightweight recreational scallop dredge for surveys of estuarine ark clams (cockles)

Arcid cockles support extensive subsistence, recreational and commercial fisheries across the world. In south-eastern Australia, there is minimal published research and a lack of quantitative surveys for the primary harvested species, Sydney Cockle Anadara trapezia, with which to inform management of the resource. Here, we describe the modification and application of an off-the-shelf lightweight recreational scallop dredge for conducting scientific surveys of arcid clams in estuarine soft sediment habitats. Specifically, we look at performance of the gear for sampling medium-large (>45 mm shell length) cockles, and report on the outcomes of preliminary trials of the gear for surveying Sydney Cockle. Efficiency trials showed that the gear captured and retained ∼95% of the cockles in the tow path, however efficiency decreased in compacted sediments (∼66%). Trial surveys captured cockles between 33 and 78 mm shell length, at densities as high as 186 individuals 100 m−2. The modified scallop dredge provides a robust and portable (∼10 kg weight) fishing gear for sampling estuarine soft sediment habitats from small vessels. Both the sampling gear, and the methodology presented here, are broadly applicable for surveying arcid cockles and other bivalve species from similar soft sediment habitats elsewhere.

Dietary supplementation of ark clams protects gut health and modifies gut microbiota in d-galactose-induced aging rats.

Ark clams, a seafood abundant in various nutrients, are widely consumed worldwide. This study aimed to investigate the protective benefits of two common ark clams in Korea, Scapharca subcrenata (SS) and Tegillarca granosa (TG), on gut health in d-galactose (d-gal)-induced aging rats. Thirty-two Wistar rats (11 weeks old) were randomly allocated into four groups: a CON group (normal diet + saline intraperitoneal (i.p.) injection), a CD group (normal diet + d-gal i.p. injection), an SS group (normal diet with 5% SS supplementation + d-gal i.p. injection), and a TG group (normal diet with 5% TG supplementation + d-gal i.p. injection). After 12 weeks of treatment, histopathological results showed that gut barrier damage was alleviated in rats of the SS and TG groups, as evidenced by increases in mucus layer thickness and goblet cell numbers. Meanwhile, the two groups supplemented with ark clams showed an evident reduction in oxidative stress biomarkers (malondialdehyde and protein carbonyl content levels in the colon) and an increase in the immune-related factor (immunoglobulin A level in the plasma) in rats. The 16S ribosomal RNA analysis revealed that SS and TG ark clams significantly increased the proliferations of Bacteroidetes at the phylum level and Parabacteroides at the genus level. Additionally, the levels of the three main short-chain fatty acids in the cecal contents were also significantly increased in the SS and TG groups. Our results indicated a potent preventive effect of SS and TG ark clams on d-gal-induced gut injury, suggesting that ark clams may be a promising dietary component for intervening in aging. © 2023 Society of Chemical Industry.

Comprehensive analysis on the regulation of differentially expressed of mRNA and ncRNA in different ovarian stages of ark shell Scapharca broughtonii

BackgroundOvarian development is an important prerequisite and basis for animal reproduction. In many vertebrates, it is regulated by multiple genes and influenced by sex steroid hormones and environmental factors. However, relative information is limited in shellfish. To explore the biological functions and molecular mechanisms of mRNA and non-coding RNA that regulate ovarian development in Scapharca broughtonii, we performed whole transcriptome sequencing analysis on ovaries at three developmental stages. Furthermore, the biological processes involved in the differential expression of mRNA and ncRNA were analyzed.ResultsA total of 11,342 mRNAs, 6897 lncRNAs, 135 circRNAs, and 275 miRNAs were differentially expressed. By mapping the differentially expressed RNAs from the three developmental stages of Venn diagram, multiple groups of shared mRNAs and lncRNAs were found to be associated with ovarian development, with some mRNA and ncRNA functions associated with steroid hormone. In addition, we constructed and visualized the lncRNA/circRNA-miRNA-mRNA network based on ceRNA targeting relationships.ConclusionsThese findings may facilitate our further understanding the mRNA and ncRNAs roles in the regulation of shellfish reproduction.

ADAPTATION OF ANADARA KAGOSHIMENSIS (TOKUNAGA, 1906) TO HYPO- AND HYPEROSMOTIC ENVIRONMENTAL CONDITIONS: HEMOCYTE RESPONSE

Anadara kagoshimensis (Tokunaga, 1906) is an invasive species that has successfully colonized the waters of the Black Sea and the sea of Azov, despite the significantly lower salinity level of these waters in comparison with the native region. The morphological and morphometric characteristics of bivalve mollusk A. kagoshimensis erythrocytes were analyzed by light microscopy during adaptation to hypo- and hyperosmotic experimental conditions. The control group of mollusks was kept at 18‰ salinity. Experimental groups were acclimated to 8, 14, 35 and 45‰ salinity. A decrease of salinity was achieved by diluting seawater with distilled water at a rate of 1.5±0.5‰ per day. Sea salt was added to each aquarium to increase salinity. Salinity was increased at a rate of 2.5±0.5‰ per day. Exposure period was 2 days. It has been shown that the salinity range of 14-35‰ is natural for ark clam. No significant changes in cell morphology were observed under these conditions. At the same time, environmental salinity levels of 8 and 45‰ caused obvious stress: cellular anomalies appeared, and the linear characteristics of erythrocytes were changed. However, cell lysis did not occur, the values of the specific surface area and nuclear-cytoplasmic ratio did not change. The results of the present work indicate the ability of the arc clam to exist for some time in regions with extremely low and high salinity of the aquatic environment.

Tribo-performance analysis of white ark shell powder/grewia optiva fiber reinforced brake friction composites

This work presents a comparative tribo-performance of two eco-friendly brake friction composites (EBFC’s), developed using white ark shell powder (WASP) and treated Grewia Optiva (GO) fibers as key ingredients, with a commercial brake friction material (CBFM). EBFC-1 and EBFC-2 were developed with 30/5: WASP/GO fiber and 25/10: WASP/GO fiber respectively using compression molding. The physico-mechanical properties of the developed samples were investigated as per IS2742: Part 3 standards. Thermal gravimetric analysis (TGA) was performed up to 800 °C to predict the thermal stability. The specimens were characterized for friction and wear properties using a tribo-test setup as per ASTM G99 standards under the normal loads varying from 100 N to 200 N at 1.7 m s−1 and 3.3 m s−1 of sliding velocities. The EBFC specimens offered lower friction coefficient and better wear resistance than the CBFM. The developed EBFCs offered better stability coefficient than the CBFM. The EBFC specimens showed good compatibility and integrity with the resin material as compared to the CBFM as evident from SEM analysis. Based on the performance, WASP may be recommended as a potential filler and GO fibers as reinforcement in brake friction compositions to enhance wear resistance, stability and minimizing the friction fluctuations.

Baseline Assessment of Marine Resources Caught by Fishermen in Selected Coastal Barangays of Cawayan, Masbate, Philippines

Marine resources have been essential for human consumption and livelihood activities, particularly for small-scale fishermen in the fishing industry. This study employed a descriptive research design, utilizing interviews and structured survey questionnaires for data collection. The findings revealed the presence of 28 fish species caught by the fishermen in Cawayan, including Asian seabass, bisugo, dolphin fish, giant trevally, gold band goatfish, grouper, lattice monocle bream, mackerel tuna, mullet, needlefish, narrow barred, octopus, oxeye scad, pink shrimp, pin spotted spinefoot, pony fish, sardines, sailfish, shark, short mackerel, slip mouth fish, squid, stingray, threadfin emperor, whiting, and yellow stripe scad. The study also identified five shellfish species, namely baler shell, fierce shell, mother-of-pearl shell, scallop, and ark shell. Seaweed species, including sea moss and sea grapes, as well as the presence of blue crab, contributed to the diverse marine ecosystem. Age emerged as a significant factor in fishing, as older fishermen exhibited extensive knowledge and expertise in identifying the caught fish species. Younger individuals, on the other hand, demonstrated physical strength and minimized the risk of work-related injuries. Notably, a significant portion of fishermen (32%) operated boats they did not own, with motorboats being the preferred choice for the majority (93%). Additionally, 72% of respondents indicated that their fishing income covered only their daily expenses, while 57% lacked alternative sources of income during unfavorable weather conditions. The researchers recommend educating and equipping fishermen with the latest fishing knowledge and skills, facilitated by collaborative efforts among the Bureau of Fisheries and Aquatic Resources (BFAR), local government units (LGUs), community extensionists, and extension workers. Sharing sustainable and advanced fishing practices will contribute to the well-being and long-term prosperity of fishing communities.

Effect of hypersalinic stress on hemocyte morphology and hemolymph cellular composition of the ark clam (Anadarakagoshimensis).

Bivalve mollusks as typical osmoconformers are unable to maintain a constant level of internal osmolarity in conditions of salinity stress. Adaptation to fluctuations of environmental salinity is achieved through cellular osmoregulatory responses, which are accompanied with a substantial shift in functional state of cells. In the present work we investigated the effect of hypersalinity stress on hemolymph cellular composition and morphology of the ark clam (Anadara kagoshimensis) hemocytes. Ark clams were subjected to a gradual increase of environmental salinity from 18‰ to 35‰ and 45‰ and maintained at those conditions for two days. Exposure to hypersalinity 35‰ induced changes in erythrocyte morphology and led to a decrease of their diameter. At salinity 45‰ a substantial increase of hemocyte average diameter was observed, whereas the shape of cells did not change (18‰). Hyperosmotic stress was not associated with changes in hemocyte viability as well as changes in hemolymph cellular composition. The results of the present work demonstrate high tolerance of A. kagoshimensis to short-time exposure to hypersalinic conditions.

Morphological Analysis of the Hemolymph Cell Composition in the Bivalve Mollusk &lt;i&gt;Anadara&lt;/i&gt; &lt;i&gt;broughtonii&lt;/i&gt; Schrenck, 1867 (Sea of Japan)

The hemolymph cells of the ark clam Anadara broughtonii were examined using light microscopy, flow cytometry and gradient centrifugation. All three methods of analysis made it possible to identify two main types of cells in the hemolymph of the ark clam Anadara broughtonii – large granular erythrocytes and small agra-nular amebocytes. Erythrocytes accounted for 95.6 ± 0.9% of the total number of hemolymph cells. Erythrocytes were hemoglobin-containing cells with a great number of granules in the cytoplasm, a low nuclear-cytoplasmic ratio (NCR) and a lower intensity of cellular respiration compared to amebocytes. Amebocytes are cells of predominantly irregular shape with a high number of cells that do not contain or contain no more than 10 granular inclusions in the cytoplasm. All types of hemocytes found in the ark clam hemolymph demonstrated the same ability to spontaneously produce reactive oxygen species. For the first time, it has been shown that red blood cells of the ark clam Anadara broughtonii are capable of phagocytosis. At the same time, amebocytes absorbed on the average two times more zymosan particles (10.3 ± 0.7 pcs.), compared to erythrocytes (5.3 ± 0.1 pcs.).

New records of bivalves from the Iraqi coast

Six marine bivalves species were recorded from the north west of the Arabian Gulf, Iraqi coast from 2020 to 2021. The species are Acar plicata (Dillwyn, 1817) (family Arcidae), Sunetta effossa (Hanley, 1843) (family Veneridae), Scissileda tropica (Melvill, 1897) (family Yoldiidae), Protapes cor (Sowerby, 1853) (family Veneridae), Circentia callipyga (Born, 1778) (family Veneridae) and Acrosterigma lacunosa (Reeve, 1845) (family Cardiidae). These records raise the number of marine bivalves known from the Iraqi coast to 38 species.

Preliminary determination of microplastics in bivalves collected from Phu Yen, central Viet Nam

In this study, four common bivalves (including Meretrix lusoria (clam), Anadara subcrenata (ark clam), Crassostrea gigas (oyster), and Perna viridi (green mussels)), which are more popularly consumed were collected from a fishery market in Phu Yen, Central Vietnam to investigate the occurrence of microplastics (MPs) in their tissues. Samples weretreated with a KOH solution of 10 % for 48 hours and incubated at 40 °C. The base-sample ratio was 10:1 v:w (i.e 10 mL of 10 % KOH solution per 1.0 gram of a tissue sample). The treatment followed by sodium iodide-based extraction was set as the protocol for the separation of MPs from biological materials. The number of MP items determined in clam, ark clam, oyster, and green mussels registered by weight and individual were 0.3 ± 0.1, 0.2 ± 0.2, 0.3 ± 0.1, and 0.5 ± 0.3(item/g-ww), and 1,4 ± 0.8, 1.5 ± 1.4, 3.0 ± 2.4, 2.3 ± 1.2 (items/individual), respectively. Fiber is the common shape (69-92% of total items), followed by fragment. Furthermore, Polyethylene terephthalate was confirmed as the polymer of the common fiber MPs found in collected samples. As the first investigation on MPs in bivalve tissue from Phu Yen, Central Vietnam, this study indicated that a relatively high level of MPs was found in the commercial bivalves collected from fishery market of Central Vietnam, warning a potentially high risk of human consuming bivalves as daily food is posed.&#x0D; Keywords: microplastics, bivalves, Phu Yen, Central Vietnam.&#x0D; Classification numbers: 3.2.1, 3.6.1.

A Putative Receptor for Ferritin in Mollusks: Characterization of the Insulin-like Growth Factor Type 1 Receptor.

The ferritin secreted by mammals has been well documented, with the protein capable of localizing to cell membranes and facilitating the delivery of iron to cells through endocytosis. However, the presence of ferritin in the circulatory fluid of mollusks and its functions remain largely unknown. In this study, we aimed to investigate the potential interacting proteins of ferritin in the ark clam (SbFn) through the use of a pull-down assay. Our findings revealed the presence of an insulin-like growth factor type 1 receptor (IGF-1R) in ark clams, which was capable of binding to SbFn and was named SbIGF-1R. SbIGF-1R was found to be composed of two leucine-rich repeat domains (L domain), a cysteine-rich domain, three fibronectin type III domains, a transmembrane domain, and a tyrosine kinase domain. The ectodomain of SbIGF-1R was observed to form a symmetrical antiparallel homodimer in the shape of the letter 'A', with the fibronectin type III domains serving as its 'legs'. The mRNA expression of SbIGF-1R gene was detected ubiquitously in various tissues of the ark clam, with the highest expression levels found in hemocytes, as determined by qRT-PCR. Using a confocal microscopic and yeast two-hybrid assays, the interaction between SbIGF-1R and SbFn was further verified. The results showed that SbFn co-localized with SbIGF-1R on the cell membrane, and their interaction was expected to occur on the FNIII domains of the SbIGF-1R. In conclusion, our findings highlight the identification of a putative receptor, SbIGF-1R, for SbFn, demonstrating the versatility of IGF-1R in ark clams.