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Introduction: Coastal marine ecosystems, are particularly susceptible to climate change. One such threat is atmospheric heatwaves, which are predicted to increase in frequency, duration, and intensity. Many intertidal organisms already live at the edge of their thermal tolerance limits and heatwaves can outstretch an organism's ability to compensate in the short term. In June 2021 the Pacific Northwest region of North America, including the Salish Sea, experienced a significant atmospheric heatwave during some of the lowest tides of the year. This was followed by numerous reports of dead and dying intertidal marine organisms region-wide. A semi-quantitative rapid assessment found a range of both species- and location-specific effects but generally recorded widespread negative impacts to intertidal shellfish species across the Salish Sea. Methods: Following these results, we opportunistically analyzed data collected by intertidal bivalve resource managers from the region. These datasets allowed us to examine regional density and size data for clam and oyster populations before and after the heatwave to increase our quantitative understanding of heatwave effects. Results: We found a range of responses including positive and negative effects of the heatwave on clam and oyster density. While we generally found small changes in bivalve size, some site-species combinations displayed large shifts in size frequency. Many of our analyses did not indicate even moderate statistical support, even with large changes in the mean, driven in part by high variability in the data. Time intervals between surveys, ranging from 2 to over 25 months, had little effect on observed variability indicating that any heatwave-induced effects may be masked by variability inherent to the population ecology and/or survey methodology. Discussion: This analysis has highlighted the need for intertidal resource managers, and the greater research community, to consider alternative survey approaches designed to constrain variability in order to detect the effects of acute or extreme events. With the effects of climate change predicted to become more intense, targeted survey approaches may be needed to detect the effects and implications of such events and to continue effective management of intertidal bivalves in the Salish Sea and worldwide. [ABSTRACT FROM AUTHOR]

The grooved carpet-shell clam is one of the most economically relevant shellfish species living in the Mediterranean and nearby Atlantic coasts. Previous studies using different types of genetic markers showed a remarkable genetic divergence of the eastern Mediterranean, western Mediterranean, and Atlantic populations, but important details remained unclear. Here, data from six nuclear introns scored for restriction fragment size polymorphisms in eight populations that have not been studied before have been pooled for the analysis with data scattered through three previous studies, totaling 32 samples from 29 locations. The results show lower levels of heterozygosity, higher mean number of alleles, and alleles with restricted distribution in the Mediterranean populations, suggesting the existence of a large, isolated population in the eastern Mediterranean at the middle Pleistocene. The data also confirm the similarity of populations from Tunisia to Western Mediterranean populations. Finally, a genetic mosaic is apparent in the Atlantic coasts of the Iberian Peninsula, with a divergence of Rias Baixas populations from more northern populations and Central Portugal populations. The effects of oceanic fronts, seasonal upwellings, river plumes, and/or fishery management operations could explain this and other features of the Atlantic populations.

The grooved carpet-shell clam is one of the most economically relevant shellfish species living in the Mediterranean and nearby Atlantic coasts. Previous studies using different types of genetic markers showed a remarkable genetic divergence of the eastern Mediterranean, western Mediterranean, and Atlantic populations, but important details remained unclear. Here, data from six nuclear introns scored for restriction fragment size polymorphisms in eight populations that have not been studied before have been pooled for the analysis with data scattered through three previous studies, totaling 32 samples from 29 locations. The results show lower levels of heterozygosity, higher mean number of alleles, and alleles with restricted distribution in the Mediterranean populations, suggesting the existence of a large, isolated population in the eastern Mediterranean at the middle Pleistocene. The data also confirm the similarity of populations from Tunisia to Western Mediterranean populations. Finally, a genetic mosaic is apparent in the Atlantic coasts of the Iberian Peninsula, with a divergence of Rias Baixas populations from more northern populations and Central Portugal populations. The effects of oceanic fronts, seasonal upwellings, river plumes, and/or fishery management operations could explain this and other features of the Atlantic populations. [ABSTRACT FROM AUTHOR]

IntroductionCoastal marine ecosystems, are particularly susceptible to climate change. One such threat is atmospheric heatwaves, which are predicted to increase in frequency, duration, and intensity. Many intertidal organisms already live at the edge of their thermal tolerance limits and heatwaves can outstretch an organism’s ability to compensate in the short term. In June 2021 the Pacific Northwest region of North America, including the Salish Sea, experienced a significant atmospheric heatwave during some of the lowest tides of the year. This was followed by numerous reports of dead and dying intertidal marine organisms region-wide. A semi-quantitative rapid assessment found a range of both species- and location-specific effects but generally recorded widespread negative impacts to intertidal shellfish species across the Salish Sea. MethodsFollowing these results, we opportunistically analyzed data collected by intertidal bivalve resource managers from the region. These datasets allowed us to examine regional density and size data for clam and oyster populations before and after the heatwave to increase our quantitative understanding of heatwave effects. ResultsWe found a range of responses including positive and negative effects of the heatwave on clam and oyster density. While we generally found small changes in bivalve size, some site-species combinations displayed large shifts in size frequency. Many of our analyses did not indicate even moderate statistical support, even with large changes in the mean, driven in part by high variability in the data. Time intervals between surveys, ranging from 2 to over 25 months, had little effect on observed variability indicating that any heatwave-induced effects may be masked by variability inherent to the population ecology and/or survey methodology. DiscussionThis analysis has highlighted the need for intertidal resource managers, and the greater research community, to consider alternative survey approaches designed to constrain variability in order to detect the effects of acute or extreme events. With the effects of climate change predicted to become more intense, targeted survey approaches may be needed to detect the effects and implications of such events and to continue effective management of intertidal bivalves in the Salish Sea and worldwide.

Phytoplankton subsidies from river inputs and wetland habitats can be important food sources for pelagic organisms in the Sacramento–San Joaquin Delta (Delta). However, while the Sacramento River is a key contributor of water to the Delta, providing 80% of the mean annual inflow, the river is only a minor source of phytoplankton to the system. The reason for low phytoplankton biomass in the Sacramento River is not well understood but appears to be associated with a 65-km stretch of the lower river where chlorophyll-a (Chl-a) concentrations can decline by as much as 90%. We conducted two surveys along the lower Sacramento River, in spring and fall of 2016, to investigate the relative contributions of different factors potentially driving this Chl-a decline. Our study evaluated the change in Chl-a concentrations as a result of dilution from tributaries, light availability, nutrient concentrations, nutrient uptake, phytoplankton productivity, zooplankton grazing, and clam grazing. Chl-a concentration decreased from 14 µg/L to 1.8 µg/L in the spring and from 4.0 µg/L to 1.2 µg/L in the fall. Dilutions from the Feather River and American River contributed 39% and 11% of Chl-a declines, respectively, during the spring. Average water depths roughly doubled downstream of the American River confluence, reducing water column light availability and lowering productivity. Zooplankton and clam grazing rates were generally low. Using a mass balance analysis, the measured variables explained 76% of the observed decline in Chl-a in the spring, suggesting additional losses from unidentified factors. We found that phytoplankton biomass is regulated by multiple potential factors in the lower Sacramento River, emphasizing the need for practitioners of restoration and management programs to evaluate multiple potential loss factors when attempting to enhance phytoplankton production in the Delta, or other large river systems.

This study examines the physiological response of the Atlantic surfclam (Spisula solidissima) to ocean acidification in warm summer temperatures. Working with ambient seawater, this experiment manipulated pH conditions while maintaining natural diel fluctuations and seasonal shifts in temperature. One-year-old surfclams were exposed to one of three pH conditions (ambient (control): 7.8 ± 0.07, medium: 7.51 ± 0.10, or low: 7.20 ± 0.10) in flow-through conditions for six weeks, and feeding and digestive physiology was measured after one day, two weeks, and six weeks. After six weeks of exposure to medium and low pH treatments, growth was not clearly affected, and, contrastingly, feeding and digestive physiology displayed variable responses to pH over time. Seemingly, low pH reduced feeding and absorption rates compared to both the medium treatment and ambient (control) condition; however, this response was clearer after two weeks compared to one day. At six weeks, suppressed physiological rates across both pH treatments and the ambient condition suggest thermal stress from high ambient water temperatures experienced the week prior (24–26 °C) dominated over any changes from low pH. Results from this study provide important information about reduced energy acquisition in surfclams in acidified environments and highlight the need for conducting multistressor experiments that consider the combined effects of temperature and pH stress. [ABSTRACT FROM AUTHOR]

The spread of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is a major public health issue. Bivalves are filter-feeder animals capable of bioaccumulating the microorganisms present in water. This physiological characteristic makes them both good indicators of environmental contamination and possible carriers of pathogenic bacteria, including those resistant to antimicrobials. The aim of this study was to investigate the occurrence of ESBL-producing E. coli in clams (n = 308) collected from harvesting areas of the Central Adriatic Sea between 2018 and 2019. ESBL-/class C β-lactamase (AmpC)- producing E. coli and Escherichia spp. were isolated by streaking over the surface of MacConkey agar plates supplemented with cefotaxime enriched broths of the initial shellfish suspension. E. coli and Escherichia spp. resistant to cefotaxime were screened for ESBL production by using the double disk synergy test. Susceptibility to different antimicrobials and confirmation of ESBL-production were determined by the minimum inhibitory concentration (MIC) test. Isolates were further characterized by whole genome sequencing (WGS) and bioinformatic analysis of genomes with different tools. Overall, ESBL-producing E. coli were isolated from 3% of the samples. Of 13 ESBL- and ESBL-/AmpC-producing Escherichia spp. (n = 11 E. coli, n = 1 E. marmotae, n = 1 E. ruysiae) isolates, 13 were resistant to ampicillin and cefotaxime, 9 to sulfamethoxazole, 6 to tetracycline and nalidixic acid, 4 to trimethoprim, and 3 to ceftazidime, cefoxitin, ciprofloxacin, and chloramphenicol. Moreover, the majority (8/11) of the ESBL-producing E. coli isolates were multidrug-resistant. WGS showed that the isolates predominantly carried the blaCTX-M-15 gene (3/11) and blaCTX-M-14 and blaCTX-M-1 (2/11 each). The AmpC β-lactamase CMY-2 was found in two isolates. Phylogroup A was the most prevalent (5/11), followed by phylogroups D (4/11), F (1/11), and B2 (1/11). Ten different sequence types (STs) were identified. Occurrence at sampling sites ranged between 0 and 27%. To identify associations between the occurrence of ESBL-producing E. coli and E. coli levels, samples were divided into two groups, with E. coli at >230 MPN/100g and E. coli at ≤230 MPN/100g. ESBL-producing E. coli isolates were significantly more commonly recovered in samples with higher E. coli levels (14%) than in those with lower levels of E. coli (2%). Moreover, the majority (3/4) of the potentially pathogenic strains were isolated in samples with higher E. coli levels. These findings provided evidence for the bacterial indicator of fecal contamination, E. coli, as an index organism for ESBL-producing E. coli isolates in bivalves. [ABSTRACT FROM AUTHOR]

The manila clam Ruditapes philippinarum has become an important bivalve species in worldwide aquaculture due to its delicious taste and high commercial value. With the rapid expansion of clam farming, there is an urgent need to obtain genetic improvement by selective breeding, such as family-based selection of improved varieties. In this study, 10 microsatellite loci were selected to establish four multiplex PCR groups using four different fluorescences (FAM, ROX, HEX, TAM). The accuracy of these loci was verified by the 100% success rate of parentage assignment in a full-sib family. Parentage assignment was carried out in the mixed-mating parents and their offspring with unknown pedigree information. The genotyping of ten microsatellite loci generated 90 alleles, having the observed heterozygosity (Ho) ranging from 0.333 to 0.729. The expected heterozygosity (He) varied from 0.358 to 0.794. The PIC ranged from 0.342 to 0.763, with a mean value of 0.620. The theoretical combined parentage exclusion (cEP) power for all ten microsatellites was 97% with known genotypes of one parent (P1) and 99% for given the genotypes of both parents (P2). The actual successful assignment rate reached 98% by using all four sets of multiplex microsatellites, serving as the effective method for parentage assignment in the clams. The development and application of multiplex microsatellite genotyping methods provide a cost-effective method for pedigree reconstruction, population genetics and selective breeding of the commercially important clams.

The spread of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is a major public health issue. Bivalves are filter-feeder animals capable of bioaccumulating the microorganisms present in water. This physiological characteristic makes them both good indicators of environmental contamination and possible carriers of pathogenic bacteria, including those resistant to antimicrobials. The aim of this study was to investigate the occurrence of ESBL-producing E. coli in clams (n = 308) collected from harvesting areas of the Central Adriatic Sea between 2018 and 2019. ESBL- /class C β-lactamase (AmpC)- producing E. coli and Escherichia spp. were isolated by streaking over the surface of MacConkey agar plates supplemented with cefotaxime enriched broths of the initial shellfish suspension. E. coli and Escherichia spp. resistant to cefotaxime were screened for ESBL production by using the double disk synergy test. Susceptibility to different antimicrobials and confirmation of ESBL-production were determined by the minimum inhibitory concentration (MIC) test. Isolates were further characterized by whole genome sequencing (WGS) and bioinformatic analysis of genomes with different tools. Overall, ESBL-producing E. coli were isolated from 3% of the samples. Of 13 ESBL- and ESBL−/AmpC-producing Escherichia spp. (n = 11 E. coli, n = 1 E. marmotae, n = 1 E. ruysiae) isolates, 13 were resistant to ampicillin and cefotaxime, 9 to sulfamethoxazole, 6 to tetracycline and nalidixic acid, 4 to trimethoprim, and 3 to ceftazidime, cefoxitin, ciprofloxacin, and chloramphenicol. Moreover, the majority (8/11) of the ESBL-producing E. coli isolates were multidrug-resistant. WGS showed that the isolates predominantly carried the blaCTX-M-15 gene (3/11) and blaCTX-M-14 and blaCTX-M-1 (2/11 each). The AmpC β-lactamase CMY-2 was found in two isolates. Phylogroup A was the most prevalent (5/11), followed by phylogroups D (4/11), F (1/11), and B2 (1/11). Ten different sequence types (STs) were identified. Occurrence at sampling sites ranged between 0 and 27%. To identify associations between the occurrence of ESBL-producing E. coli and E. coli levels, samples were divided into two groups, with E. coli at >230 MPN/100 g and E. coli at ≤230 MPN/100 g. ESBL-producing E. coli isolates were significantly more commonly recovered in samples with higher E. coli levels (14%) than in those with lower levels of E. coli (2%). Moreover, the majority (3/4) of the potentially pathogenic strains were isolated in samples with higher E. coli levels. These findings provided evidence for the bacterial indicator of fecal contamination, E. coli, as an index organism for ESBL-producing E. coli isolates in bivalves.

This study examines the physiological response of the Atlantic surfclam (Spisula solidissima) to ocean acidification in warm summer temperatures. Working with ambient seawater, this experiment manipulated pH conditions while maintaining natural diel fluctuations and seasonal shifts in temperature. One-year-old surfclams were exposed to one of three pH conditions (ambient (control): 7.8 ± 0.07, medium: 7.51 ± 0.10, or low: 7.20 ± 0.10) in flow-through conditions for six weeks, and feeding and digestive physiology was measured after one day, two weeks, and six weeks. After six weeks of exposure to medium and low pH treatments, growth was not clearly affected, and, contrastingly, feeding and digestive physiology displayed variable responses to pH over time. Seemingly, low pH reduced feeding and absorption rates compared to both the medium treatment and ambient (control) condition; however, this response was clearer after two weeks compared to one day. At six weeks, suppressed physiological rates across both pH treatments and the ambient condition suggest thermal stress from high ambient water temperatures experienced the week prior (24–26 °C) dominated over any changes from low pH. Results from this study provide important information about reduced energy acquisition in surfclams in acidified environments and highlight the need for conducting multistressor experiments that consider the combined effects of temperature and pH stress.

Freshwater clams or also known as pokes in tribal languange is clams to Sulawesi which posses high market value. However, their density and habitat preferences in Laeya River Estuary is currently unknown. This study aims to determine the density and habitat preferences of pokea clams in the Laeya River, Southeast Sulawesi. This research was conducted for 1 year from March 2016-February 2017. Pokea samples were taken every month in three stations using tangge (traditional fishing gear) with a total sample size of 2908 individuals. The density of pokea clam was analyzed using Mann Whitney test. Habitat preferences were analyzed by correspondence analysis using XLstat. The study showed that the density of pokea clams in 3 stations were similar. The clam density at stations I, II, and III were 85,47±66,44, 97,03± 81,70, and 59,84±82,31, respectively. The highest density was found during April-July 2016 with the peak density in May 2016 with a value of 268,78±29,23. The lowest density occurred during September 2016-February 2017. The lowest density was found in December 2016 with a value of 15,12±7,08. The density of pokea clams in the Laeya River was influenced by TDS. Pokea clams prefer habitats with deeper water and low brightness caused by organic matter and high TOM. [ABSTRACT FROM AUTHOR]

As population activity is increasing and the Kapuas River is still a means of transportation, causing Corbicula largillierti to accumulate heavy metals (Pb) and Coliform bacteria in their bodies. This makes it dangerous to be consumed by humans. Thus, this research has two main aims. First, to find out the concentration of Pb and Coliform inside C. largillierti that lives at Kapuas River, Pontianak and the river's water. Second, to analyze the health risk of consuming the clams. Furthermore, the Atomic Absorption Spectrophotometer (AAS) is used to analyze the Pb sample and the Most Probable Number (MPN) method is used to analyze the Coliform. The result of this research shows that concentrations of Pb and Coliform from the Kapuas River have exceeded the limits designated for aquatic biota based on the Decree of the State Minister for the Environment No. 51 of 2004. In addition, the health risk is measured using Estimated Daily Intake (EDI), Target Hazard Quotient (THQ), and Target Carcinogenic Risk (TR) with scores for each >10 times the RfD, >1, and 10-3. This result shows that based on the clam C. largillierti consumption for 70 years life span of 60 kg body weight, had a high and negative effect on health risk problems and had a cancer risk for consumers. However, the health risk problem might increase much worse due to the long and continual period of consumption exceeding the estimated daily intake. [ABSTRACT FROM AUTHOR]

This study investigated the presence of microplastics in two common edible bivalves in Vietnam, the hard clam (Meretrix lyrata) and the undulate venus clam (Paratapes undulatus), from two estuaries in Da Nang city. Microplastics were detected in both species with relatively high concentrations—from 2.17 ± 0.43 to 2.38 ± 1.28 items g−1 in the undulate venus clams and from 4.71 ± 2.15 to 5.36 ± 2.69 items g−1 in the hard clams. Fibers were the most dominant form of microplastic in both clams, and a high proportion were fibers with sizes from 300 μm to 1500 μm. An estimation of microplastic intake in Vietnamese consumers' bodies from clam consumption was made, which showed an average ingestion of 2489 items person−1 year−1. Our study is also the first global record of microplastic distribution characteristics in the undulate venus clam Paratapes undulatus. [ABSTRACT FROM AUTHOR]

Phytoplankton subsidies from river inputs and wetland habitats can be important food sources for pelagic organisms in the Sacramento--San Joaquin Delta (Delta). However, while the Sacramento River is a key contributor of water to the Delta, providing 80% of the mean annual inflow, the river is only a minor source of phytoplankton to the system. The reason for low phytoplankton biomass in the Sacramento River is not well understood but appears to be associated with a 65-km stretch of the lower river where chlorophyll-a (Chl-a) concentrations can decline by as much as 90%. We conducted two surveys along the lower Sacramento River, in spring and fall of 2016, to investigate the relative contributions of different factors potentially driving this Chl-a decline. Our study evaluated the change in Chl-a concentrations as a result of dilution from tributaries, light availability, nutrient concentrations, nutrient uptake, phytoplankton productivity, zooplankton grazing, and clam grazing. Chl-a concentration decreased from 14 µg L-1 to 1.8 µg L-1 in the spring and from 4.0 µg L-1 to 1.2 µg L-1 in the fall. Dilutions from the Feather River and American River contributed 39% and 11% of Chl-a declines, respectively, during the spring. Average water depths roughly doubled downstream of the American River confluence, reducing water column light availability and lowering productivity. Zooplankton and clam grazing rates were generally low. Using a mass balance analysis, the measured variables explained 76% of the observed decline in Chl-a in the spring, suggesting additional losses from unidentified factors. We found that phytoplankton biomass is regulated by multiple potential factors in the lower Sacramento River, emphasizing the need for practitioners of restoration and management programs to evaluate multiple potential factors when attempting to enhance phytoplankton production in the Delta, or other large river systems. [ABSTRACT FROM AUTHOR]

Thyroid cancer is the most common endocrine cancer. Papillary thyroid cancer (PTC) is the most prevalent form of malignancy among all thyroid cancers arising from follicular cells. Fine needle aspiration cytology (FNAC) is a non-invasive method regarded as the most cost-effective and accurate diagnostic method of choice in diagnosing PTC. Identification of BRAF (V600E) mutation in thyroid neoplasia may be beneficial because it is specific for malignancy, implies a worse prognosis, and is the target for selective BRAF inhibitors. To the authors' best knowledge, this is the first automated precision oncology framework effectively predict BRAF (V600E) immunostaining result in thyroidectomy specimen directly from Papanicolaou-stained thyroid fine-needle aspiration cytology and ThinPrep cytological slides, which is helpful for novel targeted therapies and prognosis prediction. The proposed deep learning (DL) framework is evaluated on a dataset of 118 whole slide images. The results show that the proposed DL-based technique achieves an accuracy of 87%, a precision of 94%, a sensitivity of 91%, a specificity of 71% and a mean of sensitivity and specificity at 81% and outperformed three state-of-the-art deep learning approaches. This study demonstrates the feasibility of DL-based prediction of critical molecular features in cytological slides, which not only aid in accurate diagnosis but also provide useful information in guiding clinical decision-making in patients with thyroid cancer. With the accumulation of data and the continuous advancement of technology, the performance of DL systems is expected to be improved in the near future. Therefore, we expect that DL can provide a cost-effective and time-effective alternative tool for patients in the era of precision oncology. [ABSTRACT FROM AUTHOR]

The liquid lead-lithium (Pb–17Li) blanket has many applications in fusion reactors due to its good tritium breeding performance, high heat transfer efficiency and safety. The compatibility of liquid Pb–17Li alloy with the structural material of blanket under magnetic field is one of the concerns. In this study, corrosion experiments China low activation martensitic (CLAM) steel and 316L steel were carried out in a forced convection Pb–17Li loop under 1.0 T magnetic field at 480 °C for 1000 h. The corrosion results on 316L steel showed the characteristic with a superficial porous layer resulted from selective leaching of high-soluble alloy elements and subsequent phase transformation from austenitic matrix to ferritic phase. Then the porous layers were eroded by high-velocity jet fluid. The main corrosion mechanism of CLAM steel was selective dissolution-base corrosion attack on the microstructure boundary regions and exclusively on high residual stress areas. CLAM steel performed a better corrosion resistance than that of 316L steel. The high Ni dissolution rate and the erosion of corroded layers are the main causes for the severe corrosion of 316L steel.

Although lacking an adaptive immune system and often living in habitats with dense and diverse bacterial populations, marine invertebrates thrive in the presence of potentially challenging microbial pathogens. However, the mechanisms underlying this resistance remain largely unexplored and promise to reveal novel strategies of microbial resistance. Here, we provide evidence that a mud-dwelling clam, Meretrix petechialis, synthesizes, stores, and secretes the antibiotic erythromycin. Liquid chromatography coupled with mass spectrometry, immunocytochemistry, fluorescence in situ hybridization, RNA interference, and enzyme-linked immunosorbent assay revealed that this potent macrolide antimicrobial, thought to be synthesized only by microorganisms, is produced by specific mucus-rich cells beneath the clam's mantle epithelium, which interfaces directly with the bacteria-rich environment. The antibacterial activity was confirmed by bacteriostatic assay. Genetic, ontogenetic, phylogenetic and genomic evidence, including genotypic segregation ratios in a family of full siblings, gene expression in clam larvae, phylogenetic tree, and synteny conservation in the related genome region further revealed that the genes responsible for erythromycin production are of animal origin. The detection of this antibiotic in another clam species showed that the production of this macrolide is not exclusive to M. petechialis and may be a common strategy among marine invertebrates. The finding of erythromycin production by a marine invertebrate offers a striking example of convergent evolution in secondary metabolite synthesis between the animal and bacterial domains. These findings open the possibility of engineering-animal tissues for the localized production of an antibacterial secondary metabolite. [ABSTRACT FROM AUTHOR]

Coalescent methods in population genetics aim to detect biodiversity patterns, evolutionary mechanisms, and signatures of historical changes in effective population sizes with respect to the species fidelity. Restriction site-associated DNA sequencing (RADseq) was used to evaluate the population dynamics of invertebrate species within the same localities. New sequencing technologies, such as the ones employed by population genetics, could be used to improve the management and sustainability of marine and aquaculture resources. Sea cucumbers (Holothuria tubolosa) showed genetic differentiation patterns favoring limited gene flow between studied areas. Similar results for clams (Venus verrucosa) suggest local adaptation and low-dispersal abilities for sessile organisms. On the contrary, cuttlefish (Sepia officinalis) exhibited a panmictic pattern, resulting in a single genetic stock in the area. The larvae settlement duration may be responsible for such interspecies variations. Interspecies demographic modeling revealed different environmental pressures of historical events' signatures with respect to the three invertebrates. Sea cucumbers favor a post-glacial bottleneck event followed by a more recent recovery, whereas cuttlefish favor an expansion before the late glacial maximum. Lastly, clams showed a constant effective population size in the area. The results of historical demographic changes in natural populations provide opportunities for critical evaluation and management in terms of the conservation of the species in the area. [ABSTRACT FROM AUTHOR]

Copper (Cu) is a ubiquitous trace element in the aquatic environment, and is usually found at low levels. Copper environmental concentrations can be altered as a result anthropogenic activities. Shellfish are useful bioindicators to ensure adequate environmental monitoring. Thus, the aim of the present study was as follows: (a) determine the LC50 of copper(I) chloride in grooved carpet shell (Ruditapes decussatus) collected in the Santa Gilla lagoon (Sardinia, Italy), and (b) analyze the antioxidant biomarkers in digestive gland and gills of same specimens exposed to different concentrations of the above-mentioned metal (0.045, 0.45, and 0.90 mg/L) for 96 h. A withdrawal period of 96 h was considered for the treated clam, carrying out the same biochemical analyses, superoxide dismutase (SOD), catalase (CAT), selenium-dependent glutathione peroxidase (Se-GPx), glutathione S-transferases (GSTs), and total glutathione (GSH+2GSSG) in the two tissues. Different time and dose responses of the antioxidant biomarkers were recorded in the digestive glands and gills. Oxidative stress biomarkers highlighted the ability of Cu to induce oxidative stress in R. decussatus. Clam, following the withdrawal period of 96 h, has not been able to achieve the control levels of all biochemical markers in the digestive gland and gills. R. decussatus can be a suitable model to assess the ecotoxicity of copper in aquatic ecosystems. These findings may advance knowledge on the role and the effects of copper on oxidative stress biomarkers in grooved carpet shell. The metal ecotoxicity response can be useful to perform accurate biomarker-based monitoring programs using this bivalve species. [ABSTRACT FROM AUTHOR]

This study explores a retrospective non-targeted analysis (NTA), based on Ultra High-Performance Liquid Chromatography coupled to High-Resolution Mass Spectrometry (UHPLC-HRMS), to assess hidden chemicals of emerging concern (CECs) in marine model organisms. Conventional ecotoxicological studies do not include evaluating the natural habitats of the collected organisms, missing the possibility of highlighting unexpected pollutants, and thus compromising the correctness and reliability of the experimental results. In this paper we reprocessed samples previously collected from the Venice Lagoon for ecotoxicological studies and used for targeted analysis of three bisphenols-related compounds (i.e. BPS, BPF and BPAF) on seawater and specimens of the clam Ruditapes philippinarum. Results from the validation were the following: accuracy, expressed as percentage recoveries (R%), in the range 80%

This work proposes the experimentation of an innovative hydraulic dredge for clam fishing (Chamelea gallina) in the Adriatic Sea (Italy). This innovative gear aimed at increasing the selectivity of the typical hydraulic dredge used currently, while at the same reducing the impact on benthos through the conception, installation, and experimentation of innovative technological solutions, consisting mainly of a vibrating bottom panel on the dredge and a “warning device” on the dredge mouth. Comparative experiments of the traditional vs. the modified gear, employing two boats fishing in parallel on the northern coast of Abruzzi (Adriatic Sea) and contrasting the catch with both paired comparisons and through modelling, showed that the innovative hydraulic dredge retains fewer undersize clams while yielding similar amounts of commercial product, moreover of higher quality; at the same time, it takes on board less discard, and catches significantly less vagile fauna. In short, the innovative gear is gaining five times over a list of six parameters considered as positive and/or advantageous for the clam fishery. The results allow proposals of potential improvements to clam-fishing instruments to make the selection processes more effective while promoting a lower impacting fishery, which is essential for clam management.

The navigation of a mobile robot is a very important issue, especially for an autonomous mobile robot. A robot autonomously can track the area by interpreting the arena, building an adequate map, and localizing itself to this map. This paper proposes a Hybrid filter for Concurrent Localization and Mapping (CLAM) in the navigation to rectify the faults, basically Unscented Fast Simultaneous Localization and Mapping (SLAM) (UFS). We also interrogate the effectiveness of the IF system to investigate nonlinear attributes. A probabilistic method has planned the solution to the CLAM issue, which is an essential requirement for the navigation of robots. The Hybrid filter CLAM contains an Intuitionistic Fuzzy Logic (IFL) and Unscented Kalman Filter (UKF). The IFL is first ordered by using a correctness function explained on score functions for the non-membership function (NMF) and membership function (MF) of the IFL. Then this ordering is utilized to develop a method for a sufficient decision on the CLAM issue. The proposed method has a few privileges in management robot navigation with nonlinear movements owing to the inference feature of the IFL, which also needs a fewer quantity of comparisons than the UFS and shows much better efficiency from the robustness, perspective assessment exactitude, and reliability than the UFS, also, for learning the measurement and control noise covariance matrices for increasing correctness and consistency are utilized IFL. The Hybrid filter CLAM proficiency compared with the UFS has a smaller quantity of computations and good efficiency for bigger areas as demonstrate in the results of simulation and experimental.

Salinity is an important environmental factor affecting the growth and survival of marine organisms. Marine shellfish possess the efficient osmoregulatory mechanism to cope with either hypo- or hyperosmotic stress. However, little is known about the molecular and metabolic adaptation involved in the osmotic regulation of these intertidal habitants. The Manila clam Ruditapes philippinarum is a worldwide cultured intertidal shellfish, which usually encounters a great risk of salinity stress in its coastal habitats. In the present study, the integrated analysis of transcriptomics and metabolomics was performed to investigate the transcriptional and metabolic profiles of the clams in response to abrupt salinity decrease. The comparative transcriptome analysis uncovers the changes of genes involved in ion channel activation, amino acid metabolism, and energy metabolism in the salinity-stressed condition. The metabolomics analysis reveals that the glucose-succinate pathway may play a critical role in energy metabolism during the osmotic stress. The multi-omics analysis reveals that neural adaptation to salinity stress may be potentially regulated by arachidonic acid metabolism and glutathione metabolism. The important metabolites (12-HPETE, PGEs, and spermine) may be served as the signaling molecules in response to acute salinity stress in the intertidal shellfish. These findings suggest that clams may get through the osmotic stress by ion channel activation, neural adaptation, and anaerobic metabolism to maintain their energy homeostasis for maximum survival. The present study provides great insights into the molecular and metabolic strategies of intertidal shellfish in response to salinity stress, and uncovers the new potential signaling metabolites to assess the health states of molluscs in aquaculture.

Objective. To determine the presence of Perkinsus sp. in the sand clam Chionista fluctifraga cultivated in an intertidal zone of the southeastern Gulf of California, using Ray's thioglycollate fluid medium staining (MFTR) and polymerase chain reaction (PCR). Material and Methods. The prevalence and parasite load of Perkinsus sp. were monthly obtained and correlated with environmental water conditions and clam biometric indicators (n=540), from May 2018 to September 2019. Results. Presumptive hypnospores of the protozoan were detected in eight months of culture. The prevalence fluctuated from 3.3% to 13.3%, while the average parasite load ranged from 2 to 1286 hypnospores/g of tissue. The intensity of infection varied from negative to light. The prevalence and parasite load were correlated with each other (r=0.61, p<0.05) but not with the environmental parameters, nor with the biometric indicators of the clam. The PCR test was negative for the MFTR positive cases. Conclusions. Presumptive hypnospores of Perkinsus sp. were detected in C. fluctifraga without clear indications of infection that compromised the clam health in culture. The constant monitoring of Perkinsus sp. in C. fluctifraga is highly recommended to establish possible infections. [ABSTRACT FROM AUTHOR]

Biomaterials such as seashells are intriguing due to their remarkable properties, including their hierarchical structure from the nanometer to the micro- or even macroscopic scale. Transferring this nanostructure to generate nanostructured polymers can improve their electrical conductivity. Here, we present the synthesis of polypyrrole using waste seashell powder as a template to prepare a polypyrrole/CaCO3 composite material. Various synthesis parameters were optimized to produce a composite material with an electrical conductivity of 2.1 × 10−4 ± 3.2 × 10−5 S/cm. This work presents the transformation of waste seashells into sustainable, electronically conductive materials and their application as an antistatic agent in polymers. The requirements of an antistatic material were met for a safety shoe sole. [ABSTRACT FROM AUTHOR]

Aquaculture is a rapidly expanding sector in which it is important to monitor the occurrence of multi-drug resistant (MDR) bacteria. The presence of extended-spectrum β-lactamase (ESBL-) or carbapenemase-producing Enterobacterales is a commonly used indicator of the resistance burden in a given sector. In this study, 641 pieces of farmed fish (sea bream and sea bass), as well as 1075 Mediterranean clams, were analyzed. All ESBL- and carbapenemase-producing Enterobacterales collected were whole-genome sequenced. The proportion of ESBL-producing Enterobacterales was 1.4% in fish and 1.6% in clams, carried by Escherichia coli (n = 23) and Klebsiella pneumoniae (n = 4). The ESBL phenotype was exclusively due to the presence of blaCTX-M genes, the most frequent one being blaCTX-M-15. The blaCTX-M-1 gene was also identified in six E. coli, among which four were carried by IncI1/pST3 plasmids, possibly betraying an animal origin. Carbapenemases were absent in fish but identified in two K. pneumoniae isolates from clams (blaNDM-1 and blaOXA-48). Several sequence types (STs) identified were associated with human MDR clones such as E. coli ST131 and ST617, or K. pneumoniae ST307 and ST147. Our results might indicate that bacteria from hospital or farm effluents can reach the open sea and contaminate seafood and fish that are living or raised nearby. Therefore, monitoring the quality of water discharged to the sea and the presence of MDR bacteria in seafood is mandatory to ensure the quality of fishery products. [ABSTRACT FROM AUTHOR]

Clams are commercially important species and are a vital component of the offshore ecosystem. Investigations on microplastics (MPs) in clams have attracted public attention recently, for its ecological and food safety risks. However, knowledge gaps still exist regarding MPs in commercial clams from the intertidal zone of the South Yellow Sea (SYS), China, an important clam habitat. In this study, to investigate the distribution of MPs in clams of the SYS, four species of clams were collected from nine sites in different tide zones (high, middle, and low tides) in three coastal areas (Nantong, Yancheng and Lianyungang). The abundance and characteristics of MPs, including size, shape, color and composition, were determined using microscope and micro-Fourier transform infrared (FTIR) spectroscopy. Furthermore, to evaluate the MPs purification ability of clams, the abundance of MPs in various tissues was examined by microscopic observation after being purified in filtered seawater for 72 h. The results showed that there were significant differences in the abundance of MPs in clams from different regions, with the most serious pollution in the high-tide zone. Moreover, the lowest MPs abundance was found in Yancheng (5.07 ± 2.73 items/individual, 1.16 ± 0.78 items/g), while Lianyungang was found with the most abundant MPs (7.52 ± 2.68 items/individual, 3.94 ± 3.00 items/g). The size of MPs in Ruditapes philippinarum (1,329.99 μm) was significantly higher than in other species. The MPs in clams were characterized by fiber in shape, black-grey, blue-green and white-transparent in color and rayon in composition. Moreover, it was found that the MPs originally present in various tissues tended to migrate and accumulate into the mantle of the clam during depuration, and after 72 h of depuration, removing the mantle could reduce nearly half amount of microplastics in clams. Overall, our study revealed the microplastic distribution in commercial clams from the intertidal zone of the SYS and provided suggestions for the safety of aquatic production.

This study investigated the presence of microplastics in two common edible bivalves in Vietnam, the hard clam (Meretrix lyrata) and the undulate venus clam (Paratapes undulatus), from two estuaries in Da Nang city. Microplastics were detected in both species with relatively high concentrations—from 2.17 ± 0.43 to 2.38 ± 1.28 items g−1 in the undulate venus clams and from 4.71 ± 2.15 to 5.36 ± 2.69 items g−1 in the hard clams. Fibers were the most dominant form of microplastic in both clams, and a high proportion were fibers with sizes from 300 μm to 1500 μm. An estimation of microplastic intake in Vietnamese consumers’ bodies from clam consumption was made, which showed an average ingestion of 2489 items person−1 year−1. Our study is also the first global record of microplastic distribution characteristics in the undulate venus clam Paratapes undulatus.

This work proposes the experimentation of an innovative hydraulic dredge for clam fishing (Chamelea gallina) in the Adriatic Sea (Italy). This innovative gear aimed at increasing the selectivity of the typical hydraulic dredge used currently, while at the same reducing the impact on benthos through the conception, installation, and experimentation of innovative technological solutions, consisting mainly of a vibrating bottom panel on the dredge and a "warning device" on the dredge mouth. Comparative experiments of the traditional vs. the modified gear, employing two boats fishing in parallel on the northern coast of Abruzzi (Adriatic Sea) and contrasting the catch with both paired comparisons and through modelling, showed that the innovative hydraulic dredge retains fewer undersize clams while yielding similar amounts of commercial product, moreover of higher quality; at the same time, it takes on board less discard, and catches significantly less vagile fauna. In short, the innovative gear is gaining five times over a list of six parameters considered as positive and/or advantageous for the clam fishery. The results allow proposals of potential improvements to clam-fishing instruments to make the selection processes more effective while promoting a lower impacting fishery, which is essential for clam management. [ABSTRACT FROM AUTHOR]

We present a genome assembly from an individual Gari tellinella (Mollusca; Bivalvia; Cardiida; Psammobiidae). The genome sequence is 1,598 megabases in span. The majority of the assembly (99.85%) is scaffolded into 19 chromosomal pseudomolecules. The complete mitochondrial genome was also assembled and is 18.5 kilobases in length.

In this work, the RAFM steels EUROFER, RUSFER and CLAM, along with a reference pure Fe sample, were all exposed to the same source of deuterium and analyzed using the same techniques, allowing a direct comparison of the experimental results. A 200 eV/D mass-selected deuterium ion beam at the SIESTA facility was used to bombard the samples to a fluence of 5 × 1024 D m−2 at 450 K. The surface morphology of the samples was investigated with Scanning Electron Microscopy. The sputter yield of the samples was determined by weight-loss measurements and confirmed by measurements of the eroded depth. The near-surface enrichment of W and Ta was investigated via Energy-dispersive X-ray spectroscopy, X-ray Photoelectron Spectroscopy and Rutherford Backscattering Spectrometry. Grain-orientation-dependent sputtering was studied with Confocal Laser Scanning Microscopy and Electron Backscatter Diffraction. Lastly, Nuclear Reaction Analysis and Thermal Desorption Spectrometry were employed to analyze deuterium retention in all the samples. The erosion behavior of all three steels under deuterium bombardment was confirmed to be similar. The measured sputter yield was comparable for all three steels, and significantly lower than that of pure Fe. Likewise, all steels develop a needle-like surface morphology under the given exposure conditions and a W- and Ta-enriched layer in the range of few nanometers, while the Fe sample remained smooth. Retained deuterium amounts were also comparable among the steel samples, and were overall larger than the retention measured for the pure Fe sample.

Se detectaron presuntas hipnosporas de Perkinsus sp. en una población silvestre de la almeja Megapitaria squalida (enero-diciembre 2013) al norte del estado de Sinaloa, México, con la técnica de tinción de tioglicolato (MFTR). Se colectaron 30 almejas cada mes (64.08 ± 4.75 mm altura de la concha y 68.76 ± 14.34 g de peso). Se obtuvieron los parámetros fisicoquímicos del agua (temperatura, salinidad, pH, oxígeno disuelto, profundidad y transparencia). La prueba MFTR detectó células esféricas de color obscuro, indicando la presencia de presuntas hipnosporas de Perkinsus sp. todos los meses de muestreo menos en diciembre. La intensidad de la infección promedio fluctuó de negativa a ligera, mientras que la prevalencia máxima fue de 70% observada en mayo. La carga parasitaria mostró correlación con los indicadores métricos de la almeja. No se obtuvo correlación (p > 0.05) entre la prevalencia del patógeno con todos los parámetros estudiados. Los resultados sugieren que M. squalida es poco susceptible a la infección de Perkinsus sp.

Copper (Cu) is a ubiquitous trace element in the aquatic environment, and is usually found at low levels. Copper environmental concentrations can be altered as a result anthropogenic activities. Shellfish are useful bioindicators to ensure adequate environmental monitoring. Thus, the aim of the present study was as follows: (a) determine the LC50 of copper(I) chloride in grooved carpet shell (Ruditapes decussatus) collected in the Santa Gilla lagoon (Sardinia, Italy), and (b) analyze the antioxidant biomarkers in digestive gland and gills of same specimens exposed to different concentrations of the above-mentioned metal (0.045, 0.45, and 0.90 mg/L) for 96 h. A withdrawal period of 96 h was considered for the treated clam, carrying out the same biochemical analyses, superoxide dismutase (SOD), catalase (CAT), selenium-dependent glutathione peroxidase (Se-GPx), glutathione S-transferases (GSTs), and total glutathione (GSH+2GSSG) in the two tissues. Different time and dose responses of the antioxidant biomarkers were recorded in the digestive glands and gills. Oxidative stress biomarkers highlighted the ability of Cu to induce oxidative stress in R. decussatus. Clam, following the withdrawal period of 96 h, has not been able to achieve the control levels of all biochemical markers in the digestive gland and gills. R. decussatus can be a suitable model to assess the ecotoxicity of copper in aquatic ecosystems. These findings may advance knowledge on the role and the effects of copper on oxidative stress biomarkers in grooved carpet shell. The metal ecotoxicity response can be useful to perform accurate biomarker-based monitoring programs using this bivalve species.

Monocrotophos (MCP) is a highly toxic and broad-spectrum pesticide extensively used for agricultural and household purposes. The present study was aimed to evaluate the genotoxicity and alterations in the biochemical and physiological conditions induced by monocrotophos in a non-target organism, an estuarine bivalve, Donax incarnatus. The bivalves were exposed to three sub-lethal concentrations (6.8, 13.7, and 27.45 ppm) of MCP for a period of 72 h. DNA damage was assessed using the comet assay. Oxidative stress was analyzed using catalase, glutathione peroxidase, and superoxide dismutase. Neurotoxicity was evaluated using the acetylcholinesterase assay (AChE) and the physiological condition was assessed using the condition index (CI). A significant concentration-dependent increase of DNA damage was observed as well as a decline in the activities of the antioxidant enzymes. However, a decrease in DNA damage was observed with advancing time. A significant decrease of AChE activity and CI was observed in the bivalves exposed to MCP. Positive correlations were also observed between DNA damage and the antioxidant enzymes whereas negative correlations were observed between AChE and the antioxidant enzymes indicating MCP toxicity mediated by oxidative stress. [ABSTRACT FROM AUTHOR]

Aquaculture is a rapidly expanding sector in which it is important to monitor the occurrence of multi-drug resistant (MDR) bacteria. The presence of extended-spectrum β-lactamase (ESBL-) or carbapenemase-producing Enterobacterales is a commonly used indicator of the resistance burden in a given sector. In this study, 641 pieces of farmed fish (sea bream and sea bass), as well as 1075 Mediterranean clams, were analyzed. All ESBL- and carbapenemase-producing Enterobacterales collected were whole-genome sequenced. The proportion of ESBL-producing Enterobacterales was 1.4% in fish and 1.6% in clams, carried by Escherichia coli (n = 23) and Klebsiella pneumoniae (n = 4). The ESBL phenotype was exclusively due to the presence of blaCTX-M genes, the most frequent one being blaCTX-M-15. The blaCTX-M-1 gene was also identified in six E. coli, among which four were carried by IncI1/pST3 plasmids, possibly betraying an animal origin. Carbapenemases were absent in fish but identified in two K. pneumoniae isolates from clams (blaNDM-1 and blaOXA-48). Several sequence types (STs) identified were associated with human MDR clones such as E. coli ST131 and ST617, or K. pneumoniae ST307 and ST147. Our results might indicate that bacteria from hospital or farm effluents can reach the open sea and contaminate seafood and fish that are living or raised nearby. Therefore, monitoring the quality of water discharged to the sea and the presence of MDR bacteria in seafood is mandatory to ensure the quality of fishery products.

Biomaterials such as seashells are intriguing due to their remarkable properties, including their hierarchical structure from the nanometer to the micro- or even macroscopic scale. Transferring this nanostructure to generate nanostructured polymers can improve their electrical conductivity. Here, we present the synthesis of polypyrrole using waste seashell powder as a template to prepare a polypyrrole/CaCO3 composite material. Various synthesis parameters were optimized to produce a composite material with an electrical conductivity of 2.1 × 10−4 ± 3.2 × 10−5 S/cm. This work presents the transformation of waste seashells into sustainable, electronically conductive materials and their application as an antistatic agent in polymers. The requirements of an antistatic material were met for a safety shoe sole.

Salinity is an important environmental factor that has a profound impact on the growth, reproduction, survival, and development of mollusk. To investigate the molecular changes in response to acute low-salinity stress, the clams were transferred from 25‰ to 8‰. According to the exposure times of 0, 12, 24, 48, 72, 96, and 120 h, the treatment consisted group T0 (the control), T1, T2, T3, T4, T5, and T6, respectively. Gills were collected, and then transcriptome analysis was conducted. Compared to the control, 3008 DEGs were obtained, including 1127 up-regulated and 1881 down-regulated genes, respectively. Up-regulations of 924, 176, 11, 6, 3, and 7 DEGs, and down-regulations of 1216, 416, 157, 59, 23, and 10 DEGs were observed in T6, T5, T4, T3, T2, and T1 groups, respectively. The related molecular biological processes, and potential functions were explored from enrichment analyses, including energy metabolism, material metabolism, and immune responses. There were 13, 10, 16, 30, 62, and 97 KEGG pathways enriched in T1, T2, T3, T4, T5, and T6 groups, respectively. 13 genes down-regulated, and only one gene up-regulated were found in more than four groups. In addition, the verification of the expression changes of the candidate genes (PCK1, IAP, BIRC2, and LOC102459116) provided insights into responses to salinity change in the gills of the clams. This will be of great value in understanding the molecular basis of low-salinity adaptation in the clam.

To investigate the defensive strategies of clam Cyclina sinensis in response to environmental ammonia exposure, we investigate the 96 h median lethal concentration (LC50-96 h) and the 96 h safe concentration (SC) of total ammonia nitrogen (TAN) for C. sinensis, and on the basis we examined glutamine synthetase (GS) activity, glutamine content, urea content and the antioxidant enzyme activities of super oxide dismutase (SOD) and catalase (CAT) in 96 h at three different levels of TAN as 0 (control), 73.94 (T1) and 227.04 mg/L (T2). Results showed that LC50-96 h and SC for C. sinensis were 65.79 and 6.58 mg/L, respectively. The LC50-96 h and SC of NH3 were 1.70 and 0.17 mg/L, respectively. Ammonia exposure had significantly effects on SOD and CAT activities in the hepatopancreas tissue. Both the level of SOD activity and CAT activity increased with increasing concentration of TAN. No significant differences between T1 and T2 were found in GS activity from 3 h to 96 h after exposed to ammonia, whereas they were significantly higher than those in the control. Both the level of glutamine content in T1 and T2 increased significantly from 6 h to 24 h after exposed to ammonia and they were significantly higher than those in the control. There were no significantly differences were found in the level of urea concentration between T1 and T2 from 6 h to 96 h, while they were significantly higher those in the control. In conclusion, enhancing hepatopancreas antioxidant responses as well as converting ammonia into glutamine and urea worked in combination to allow C. sinensi to defend against acute ammonia exposure.

We face a food crisis. Suboptimal diet is the biggest cause of death worldwide, food production the biggest greenhouse gas emitting sector, and by 2050 an extra 2.5 billion people need affordable nutrition. Current farming systems will fail to tackle this crisis, and there is an urgent need to diversify global food production and find effective solutions in currently underexploited food sectors. Shipworms, or shell-less Teredo clams, could prove a highly valuable component of such solutions. Historically viewed as a marine pest, they have unique physiological characteristics which make them an ideal food source, including exceptionally fast growth rates, the ability to feed on waste wood or sustainable microalgae, and a high protein and omega 3 content. Today only a select few traditional cultures in the Philippines consume shipworms, but there is considerable opportunity to develop mechanisms to farm shipworms and provide a sustainable, nutrient rich, affordable food source. This will require significant challenges to be overcome, ranging from fundamental research to industry development to food processing and marketing. Leveraging new innovations in breeding, aquaculture feeds, growth systems, food processing methodologies and consumer engagement can however offer powerful solutions, and could help turn what was once a maritime villain into a nutritional savior.

Abstract The ecological and ethnological aspects of the harvesting of the cockle, Leukoma pectorina (Bivalvia: Veneridae), were investigated on Algodoal-Maiandeua Island, on the Amazon coast of Brazil. Ethnobiological data were collected through informal conversations, semi-structured interviews, and observations of the harvesting and processing of bivalves on the island. Following the ethnobiology study, the cockle beds were surveyed to evaluate the density of L. pectorina, body size and the meat yield of the cockles in the months of dry and rainy seasons. In the study area, cockling is a manual and artisanal activity, and L. pectorina is typically harvested by mothers with little formal education. The cocklers make their own tools, cockles are prepared in the family environment, and the majority of the catch is sold to commercial establishments on the island. Cockling is a sporadic activity used to complement the family income, and is more common during the dry season, when tourism increases on Algodoal-Maiandeua Island. The cockles are also larger and population density is higher during this season, and the cocklers themselves recognize this period as providing the most productive harvest. These findings reinforce the value of traditional knowledge for both scientific research and the planning of the management of coastal fishery resources.

The hydrothermal vent clam Calyptogena magnifica (Bivalvia: Mollusca) is a member of the Vesicomyidae. Species within this family form symbioses with chemosynthetic Gammaproteobacteria. They exist in environments such as hydrothermal vents and cold seeps and have a rudimentary gut and feeding groove, indicating a large dependence on their endosymbionts for nutrition. The C. magnifica symbiont, Candidatus Ruthia magnifica, was the first intracellular sulfur-oxidizing endosymbiont to have its genome sequenced (Newton et al. 2007). Here we expand upon the original report and provide additional details complying with the emerging MIGS/MIMS standards. The complete genome exposed the genetic blueprint of the metabolic capabilities of the symbiont. Genes which were predicted to encode the proteins required for all the metabolic pathways typical of free-living chemoautotrophs were detected in the symbiont genome. These include major pathways including carbon fixation, sulfur oxidation, nitrogen assimilation, as well as amino acid and cofactor/vitamin biosynthesis. This genome sequence is invaluable in the study of these enigmatic associations and provides insights into the origin and evolution of autotrophic endosymbiosis.

The Heat shock proteins (HSPs) are a group of molecular chaperones that play a crucial role in cell response to various stresses. A full-length cDNA of the heat shock protein 90 (PuHsp90) was cloned and sequenced from the clam Paphia undulata. Phylogenetic analysis revealed that PuHsp90 grouped with the Hsp90 from other metazoan species. Expression of PuHsp90 was highly detected in the gonad, followed by digest gland, gills and heart but was found poorly expressed in mantle, adductor muscle and hemocytes. After a heat shock stress at 32 °C up-regulation of PuHsp90 was detected in the mantle, adductor muscle, gills and hemocytes. Maximal expression levels occurred at 4 h after the heat shock and up-regulation is indicative of protein denaturation and of an increase in energy consumption. In contrast after the heat shock, PuHsp90 was continuously down-regulated in the digestive gland and in the gonad suggesting modifications of the biochemical pathways and energy budgets involved in the synthesis of other protein, such as catalase and of other Hsp proteins. These results reveal that PuHsp90 may play an important role in the clam response to a temperature stress.

Bivalves are a good source of nutrients but also a potential source of environmental contaminants, which could pose a risk for consumers. The aims of this study were: the determination of 16 elements by ICP-MS in 48 samples of five bivalve species purchased from market in Korea; the identification of elements useful for species classification using multivariate analyses; and the benefit-risk evaluation associated to the consumption of these bivalves. The highest difference among content of elements between species was found for Cd, Mn, Ni, Zn, and Fe. Partial last squares discriminant analysis revealed elements with a VIP score >1 which were considered as the most relevant for explaining certain species. As, Cd, Co, and Ni were found as taxonomical markers of V. philippinarum; Mn, Zn, Mg, and Na of A. irradians; and Cd, Ni, and Fe of M. yessoensis. These species could serve as good dietary sources of essential elements. Cd exposure by consumption of Manila clams is not representing a health risk for the Korean population; however, through consumption of Yesso scallops, 5.3% of the Korean population has a potential health risk. Removal of the digestive gland before eating will drastically reduce the amount of Cd ingested.

The present study reported parasites and its histopathological effects on the tissue of the popular seafood clam Paphia undulata. Some parasites were found to have several effects on shellfish aquaculture production. Samples of clams were collected from Damietta shore, Egypt. Histopathological examination was conducted on the gills, gonads, and intestine of clams. Two types of parasites were detected in the infected clams (protozoans and nematodes). The identification of Protozoa was confirmed by using the electron microscope. This study revealed that 51% of P. undulata were infected with parasites. The highest infection was noticed in the clam size ranged from 2.1 to 4 cm. This infection declined with the larger clams. The current study proved that there was a negative association between the prevalence of parasites and clam size. Histopathological effects of parasites on the clam gills, gonads, and intestine were detected. Parasites not only affect clams but may also be transmitted to consumers after eating undercoocked shellfish. So, this study warns against eating raw seafood as it is considered a vehicle for the transmission of human parasites. [ABSTRACT FROM AUTHOR]

Freshwater bivalves in shallow waters are often exposed to extended periods of drought and are highly affected due to their limited mobility. Their adaptation to emersion is a key factor for survival, particularly during human-made unnatural water regime fluctuations or short-term droughts. In the current study, survival durations of two freshwater bivalve species (Unio terminalis, Unionidae and Corbicula fluminea, Cyrenidae) were tested under two experimental emersion conditions (presence of water-saturated sediment and without sediment). U. terminalis' mean survival duration more than doubled in the water-saturated sediment treatment (992 h) compared to treatment without sediment (448 h). For C.fluminea, the mean survival duration in the water-saturated sediment treatment (278 h) was over 50% longer than that recorded in the treatment without sediment (174 h). Both species probably made behavioral adjustments according to the environmental conditions to respond to the presence of the water-saturated sediment and maximized their survival chances. In general, U. terminalis survived significantly longer than C.fluminea in both treatments. No effects of size on survival were observed for either species. Freshwater bivalves are often exposed to drought and are highly affected due to their limited mobility. According to the results, the presence of moist sediment during droughts provide protection for the bivalve species used in the study and extended survival durations. Additionally, no evidence was found regarding the effect of size on survival. [ABSTRACT FROM AUTHOR]

The effects of normalizing and tempering temperatures on the microstructures and mechanical properties of China Low Activation Martensitic (CLAM) steel with and without yttrium were studied. Based on the optimized traditional heat treatment, two special intermediate heat treatments were studied to improve the mechanical properties of the steels. The AC3 temperature of the CLAM steel was increased by adding yttrium. The optimized traditional heat treatments were 1000 °C × 30 min + 755 °C × 90 min and 1050 °C × 30 min + 755 °C × 90 min for the C1 and C2 alloys, respectively. The intermediate heat treatment results indicated that the precipitation behavior of carbides was effectively controlled. The size of the M23C6 carbides was refined during the two intermediate heat treatments due to the priority precipitation of MX particles. However, coarsening of grains and martensite laths occurred during heat treatment with furnace cooling. The twice-quenched tempering samples had a smaller grain size and martensite lath width than the other samples. The ductile–brittle transition temperature was − 69 and − 103 °C for the C1 and C2 alloys with twice quenching, and the yield strengths were 745 and 760 MPa, respectively. An excellent balance of strength and impact toughness was obtained with the twice-quenching and once tempering heat treatment process. [ABSTRACT FROM AUTHOR]

The current study shows the compositional changes and oxidation development of clam (Ruditapes philippinarum, R. philippinarum) lipids and frying oils when subjected to different processing conditions. Parameters measured include acid value, peroxide value (POV), thiobarbituric acid‐reactive substances (TBARS), total oxidation (TOTOX), lipid classes, fatty acid composition, phosphatidylcholine (PC), and phosphatidylethanolamine (PE) contents together with major glycerophospholipid (GP) molecular species. Deep‐fat frying increased triacylglycerol (TAG) content and decreased the contents of PC, PE, and GP molecular species in clam in a time‐dependent manner. Meanwhile, minor amounts of free fatty acids, diacylglycerols, monoacylglycerols, and polar lipids were detected in frying oils, indicating lipid migration between the clam and frying oils. The time‐dependent increase of POV, TBARS, and TOTOX in fried clams and frying oils with concurrent reduction of docosahexenoic acid and eicosapentaenoic acid indicates extensive oxidative degradation of clam lipids. Moreover, the moisture‐rich clam aggravated the deterioration of frying oils. Consequently, deep‐fat frying significantly altered the lipid profile and decreased the nutritional value of clams. [ABSTRACT FROM AUTHOR]