Ark Shell Research Articles

Effects of temperature and salinity on survival and growth of juvenile ark shell Anadara broughtonii

We investigated the combined effects of temperature (23, 26, 29 and 32 °C) and salinity [15, 18, 21, 24, 27 and 30 practical salinity units (PSU)] on the growth and survival of juvenile ark shell Anadara broughtonii under hatchery conditions. Mortality, shell length and shell height were monitored for a period of 25 days in all exposure groups. Survival greater than 98% was observed in all treatment groups with no significant difference among treatment combinations. Absolute growth and specific shell length and height growth rate were significantly influenced by temperature and salinity. Growth of juvenile A. broughtonii increased with higher salinity and peaked at an intermediate temperature (26 °C). Optimal specific growth rates of 4.64 ± 0.04% day−1 by shell length and 4.76 ± 0.11% day−1 by shell height were observed at a combination of 26 °C and 30 PSU. This study enhances our understanding of the biology of A. broughtonii and determines ideal environmental conditions for pre-planting culture operations.

Physiological and molecular response of Anadara tuberculosa (Arcoida: Arcidae) to salinity stress.

The pustulose ark A. tuberculosa is an emblematic species of mangrove ecosystem that is currently in a vulnerable condition. The development of its aquaculture, to begin with genetic breeding programs, requires the identification of molecular biomarkers, particularly those associated with salinity stress. With this purpose, specimens of A. tuberculosa were collected from the adjacent mangroves of Puerto Pizarro bay (Tumbes, Peru), from January 2015 to February 2016. Different assays (groups of ten animals in triplicate) were undertaken in separated periods of 16 days: hypo-osmotic stress (extreme: 5, 10 ppt); (Moderate: 15, 25 ppt) and no stress (control group: 33 ppt). The presence of salinity stress biomarkers was assessed at the genetic level throughout PCR detection of 19 genes reported to be key actors in osmoregulation, and at the proteomic level with the sequencing of peptides (tandem mass spectrometry MALDI TOF/TOF), expressed in ark tissues exposed to different salinities. None of the tested genetic markers could be amplified by PCR, suggesting that A. tuberculosa has significant genetic differences compared to other mollusks. Proteomic analysis by mass spectrometry on A. tuberculosa gill tissue, allowed to identify 26 peptides expressed in presential and differential forms at different salinities, highlighting possible markers such as HSP70 and trans-membrane chloride channel transportation protein, to be related with salinity adaptation. These amino acid sequences will allow the design of target specific primers for A. tuberculosa, to implement future research in ecophysiology of this important fishery resource.

Target K-shell ionization accompanied by single and double capture in [formula omitted] collisions

Cross sections for target Ar K-shell X-ray emission accompanied by single and double electron capture, as well as the total cross sections for single and double electron capture, have been measured for incident 1.8–2.4MeV/uF9+ ions colliding with Ar. Coincidences between the detected X-rays and the charge-changed projectile ions were recorded. Preliminary analysis indicates total cross sections for single electron capture on the order 10-17cm2, with those for double capture being about an order of magnitude smaller. The corresponding cross sections for target K-shell X-ray emission accompanied by single and double electron capture, despite being about 103 times smaller, are nearly flat and approximately equal, a result that was not expected.

Observation and modeling of interspecies ion separation in inertial confinement fusion implosions via imaging x-ray spectroscopy

We report the first direct experimental evidence of interspecies ion separation in direct-drive inertial confinement fusion experiments performed at the OMEGA laser facility via spectrally, temporally, and spatially resolved imaging x-ray-spectroscopy data [S. C. Hsu et al., Europhys. Lett. 115, 65001 (2016)]. These experiments were designed based on the expectation that interspecies ion thermo-diffusion would be the strongest for species with a large mass and charge difference. The targets were spherical plastic shells filled with D2 and a trace amount of Ar (0.1% or 1% by atom). Ar K-shell spectral features were observed primarily between the time of first-shock convergence and slightly before the neutron bang time, using a time- and space-integrated spectrometer, a streaked crystal spectrometer, and two gated multi-monochromatic x-ray imagers fielded along quasi-orthogonal lines of sight. Detailed spectroscopic analyses of spatially resolved Ar K-shell lines reveal the deviation from the initial 1% Ar gas fill and show both Ar-concentration enhancement and depletion at different times and radial positions of the implosion. The experimental results are interpreted using radiation-hydrodynamic simulations that include recently implemented, first-principles models of interspecies ion diffusion. The experimentally inferred Ar-atom fraction profiles agree reasonably with calculated profiles associated with the incoming and rebounding first shock.

Development and validation of an accurate and sensitive LC-ESI-MS/MS method for the simultaneous determination of paralytic shellfish poisoning toxins in shellfish and tunicate

An analytical method using liquid chromatography-tandem mass spectrometry has been developed for the determination of 5 paralytic shellfish poisoning (PSP) toxins (saxitoxin, gonyautoxin1-4) in shellfish and tunicate. The tested parameters included extraction solvent, clean-up method, mobile phase and mass spectrometric detection parameters including multiple reaction monitoring (MRM) conditions. The PSP toxins were extracted with 0.1 N hydrochloric acid and cleaned up using C18 SPE cartridges. Chromatographic separation of the 5 PSP toxins was carried out on a TSK-gel Amide-80 column with gradient elution. The developed method was validated according to the requirements of SANCO 12571/2013. The average recoveries of the PSP toxins ranged from 82.7% to 110.7%, the intra-day precisions were in the range of 0.3–10.9%, the inter-day precisions were in the range of 0.8–10.0% and the limits of quantification (LOQs) were in the range of 25–100 μg/kg, depending on the analytes and matrices. The validated method was successfully applied for the determination of 5 PSP toxins in real shellfish and tunicate samples, including mussel, oyster, ark shell, sea squirt and styela clava.

Bioaccumulation of heavy metals and health risk assessment in three benthic bivalves along the coast of Laizhou Bay, China

This study investigated the tissue- and species-specific bioaccumulation of heavy metals (Cr, Cu, Hg, Zn, As, Cd, and Pb) in three benthic bivalves (the ark shell, Scapharca subcrenata; the surf clam, Mactra veneriformis; and the Manila clam, Ruditapes philippinarum) collected from the coast of Laizhou Bay in the Bohai Sea. The results demonstrated that the visceral masses of the bivalves tended to accumulate heavy metals more efficiently than their muscles. The capacities of the bivalves to bioaccumulate metals followed a similar order: Cd>Hg>Zn=As>Cu>Cr=Pb. The conditions of metal contamination in the bivalves tended to be worse along the eastern coast than in other regions. Overall, the Manila clam was more severely contaminated by heavy metals than the surf clam and ark shell. Judging by the hazard quotients (HQ) of the metals in the muscles of the bivalves, the greatest hazard risk to human health comes primarily from As.

꼬막껍질을 이용한 김치 저장 용기의 종류별 저장 기간에 따른 갓 물김치의 품질 특성

꼬막껍질을 이용한 김치 저장 용기의 종류별 저장 기간에 따른 갓 물김치의 품질 특성

Development and characterization of 37 SNP markers in the ark shell Scapharca subcrenata using RAD sequencing and high resolution melting analysis

The ark shell Scapharca subcrenata, an important fishery resource in Asian countries, has been suffering from severe population decline in recent years. To facilitate genetic conservation studies, novel single nucleotide polymorphisms (SNPs) markers were developed using next generation sequencing for this species, which yielded a total of 781,860 putative SNPs. To validate these markers, 96 SNP genotyping assays were designed to characterize polymorphisms using high resolution melting (HRM) analysis in 32 individuals from a wild population. As a result, 37 SNPs showed polymorphisms with MAF ranging from 0.0313 to 0.4844. The observed heterozygosity ranged from 0 to 0.8333, while the expected heterozygosity varied from 0.0605 to 0.4995. After the Bonferroni correction, 5 of the 37 loci showed significant departure from Hardy–Weinberg equilibrium. These novel SNP markers will be useful for future investigation of population structure and conservation genetics of the ark shell S. subcrenata.

Ark shell protein hydrolysates inhibit adipogenesis in mouse mesenchymal stem cells through the down-regulation of transcriptional factors

Anti-adipogenic peptides were generated from ark shell protein by enzymatic hydrolysis.

Experimental infection of adult Scapharca broughtonii with Ostreid herpesvirus SB strain

We investigated the susceptibility of ark shell, Scapharca broughtonii, adults to Ostreid herpesvirus SB strain (OsHV-1-SB) through experimental infection by intramuscular injection assays. Results showed the onset of mortality occurred at 3days post injection, one day after the water turbidity became evident in rearing tanks. The mortality curves for the challenged group were similar to those observed at affected hatcheries. Histological lesions, herpesvirus-like particles and high OsHV-1-SB quantities were detected in challenged ark shells. This is the first study to successfully reproduce OsHV-1 disease in Arcoida species, and very few studies in adult bivalves (over 24months old).

Effects of a Xe dopant on an Ar gas-puff implosion on Z

Two Ar gas-puff experiments, each using loads consisting of two annuli and a center jet, were recently performed on Sandia National Laboratories' Z machine. These shots had the same load except that one of them (Z2603) employed a Xe dopant of 0.8% by number in the jet, which was not present in the otherwise identical Z2605. The extensive diagnostics deployed in these experiments reveal that the presence of this small fraction of Xe had a significant effect on the emitted K-shell radiation. Use of the Xe dramatically reduced the Ar K-shell yield from 373 ± 9% to 129 ± 9% kJ. However, the total yield increased, from 1.02 ± 17% to 1.14 ± 17% MJ. Also, the K-shell power pulse for Z2603 exhibited two nearly equal peaks separated by ∼5 ns, but that of Z2605 consisted of a more conventional single peak. Analysis of time- and space resolved K-shell spectra using a detailed atomic model for Ar ions indicates that a much greater fraction of the load mass was heated to the K-shell in the non-Xe shot Z2605. Previous ...

Habitat suitability of Scapharca subcrenata (Lischke) in the shallow water of the Xiaoheishan Island

The habitat suitability index (HSI) model was used to identify potential sites for sustainable restoration of ark shell, Scapharca subcrenata (Lischke), in the shallow water of Xiaoheishan Island, using a geographic information system framework. The seven input variables of the HSI model were sediment composition, water temperature, salinity, dissolved oxygen, water depth, pH, and ammonia. A non-linear suitability function for each variable factor was used to transform the value into a normalized quality index ranging from 0 (nonsuitability) to 1 (best suitability). In present study, the analysis of habitat suitability was conducted for four seasons respectively. The majority of the study area has a high HSI value (>0.6) year round, which implies a strong suitability for restoration, with the optimal habitat located on the eastern side of the island. Correspondence analysis indicated that water temperature was the main factor causing seasonal variation, while sediment composition and water depth were the two major reasons for the differences in sites. The results of this work could provide support for restoration decision making through identification of potential sites for sustainable establishment of S. subcrenata.

Changes in hemolymph characteristics of ark shell Scapharaca broughtonii dealt with Vibrio anguillarum challenge in vivo and various of anticoagulants in vitro

The ark shell Scapharca broughtonii is a commercially important shellfish in China. Alserver's solution (AS), modified Alserver's solution (MAS) and Heparin sodium solution (HSS) are common anticoagulants used for shellfish blood. To observe the immune response mediated by its hemocytes, we challenged in vivo S. broughtonii hemolymph with Vibrio anguillarum and dealt with the following three anticoagulants in vitro: Alserver's solution (AS), modified Alserver's solution (MAS) and Heparin sodium solution (HSS). The methodologies we used were immunostimulation with V. anguillarum, Wright-Giemsa staining, micro-examination, and flow cytometric and hydrolyzing enzyme activity analysis. The results showed that all three types of anticoagulants effectively prevented blood clotting in ark shellfish. The morphology of hemocytes did not significantly change 30 h after anticoagulant treatment, except for the shrinking of hemocytes after administering HSS. The size and permeability of hemocytes changed when treated with the anticoagulants and when stimulated with V. anguillarum. Both alkaline phosphatase (AKP) and acid phosphatase (ACP) in hemocytes and Plasma were measured at different times after they were stimulated with V. anguillarum in HSS and MAS. The AKP enzymatic activity in HSS was somewhat higher than in the MAS anticoagulant, but changes in response to V. anguillarum challenge of enzymatic activity were almost the same in HSS and MAS groups. In conclusion, all three types of anticoagulants may be used for ark shell blood preservation. They all changed the cell-surface characteristics of hemocytes to inhibit clot formation. The AS anticoagulant was appropriate for maintaining white and red cell shapes, while MAS was ideal for retaining throbus cell function. Lastly, HSS was appropriate for maintaining enzymatic activity in hemolymph and function of hemocytes. Following this investigation, we gained insight into the changes in hemolymph characteristic during immune response.

전남 여자만 해수 및 새꼬막(Scapharca subcrenata)의 세균학적 위생 평가

전남 여자만 해수 및 새꼬막(Scapharca subcrenata)의 세균학적 위생 평가

Mitogen–activated protein kinase 1 from disk abalone (Haliotis discus discus): Roles in early development and immunity-related transcriptional responses

Mitogen–activated protein kinase (MAPK) is involved in the regulation of cellular events by mediating signal transduction pathways. MAPK1 is a member of the extracellular-signal regulated kinases (ERKs), playing roles in cell proliferation, differentiation, and development. This is mainly in response to growth factors, mitogens, and many environmental stresses. In the current study, we have characterized the structural features of a homolog of MAPK1 from disk abalone (AbMAPK1). Further, we have unraveled its expressional kinetics against different experimental pathogenic infections or related chemical stimulants. AbMAPK1 harbors a 5′ untranslated region (UTR) of 23 bps, a coding sequence of 1104 bps, and a 3′ UTR of 448 bp. The putative peptide comprises a predicted molecular mass of 42.2 kDa, with a theoretical pI of 6.28. Based on the in silico analysis, AbMAPK1 possesses two N-glycosylation sites, one S_TK catalytic domain, and a conserved His-Arg-Asp domain (HRD). In addition, a conservative glycine rich ATP-phosphate-binding loop and a threonine-x-tyrosine motif (TEY) important for the autophosphorylation were also identified in the protein. Homology assessment of AbMAPK1 showed several conserved regions, and ark clam (Aplysia californica) showed the highest sequence identity (87.9%). The phylogenetic analysis supported close evolutionary kinship with molluscan orthologs. Constitutive expression of AbMAPK1 was observed in six different tissues of disk abalone, with the highest expression in the digestive tract, followed by the gills and hemocytes. Highest AbMAPK1 mRNA expression level was detected at the trochophore developmental stage, suggesting its role in abalone cell differentiation and proliferation. Significant modulation of AbMAPK1 expression under pathogenic stress suggested its putative involvement in the immune defense mechanism.

Simulations of Ar gas-puff Z-pinch radiation sources with double shells and central jets on the Z generator

Radiation-magnetohydrodynamic simulations using the non-local thermodynamic equilibrium Mach2-Tabular Collisional-Radiative Equilibrium code in (r, z) geometry are performed for two pairs of recent Ar gas-puff Z-pinch experiments on the refurbished Z generator with an 8 cm diameter nozzle. One pair of shots had an outer-to-inner shell mass ratio of 1:1.6 and a second pair had a ratio of 1:1. In each pair, one of the shots had a central jet. The experimental trends in the Ar K-shell yield and power are reproduced in the calculations. However, the K-shell yield and power are significantly lower than the other three shots for the case of a double-shell puff of 1:1 mass ratio and no central jet configuration. Further simulations of a hypothetical experiment with the same relative density profile of this configuration, but higher total mass, show that the coupled energy from the generator and the K-shell yield can be increased to levels achieved in the other three configurations, but not the K-shell power. Based on various measures of effective plasma radius, the compression in the 1:1 mass ratio and no central jet case is found to be less because the plasma inside the magnetic piston is hotter and of lower density. Because of the reduced density, and the reduced radiation cooling (which is proportional to the square of the density), the core plasma is hotter. Consequently, for the 1:1 outer-to-inner shell mass ratio, the load mass controls the yield and the center jet controls the power.

Investigating the effect of adding an on-axis jet to Ar gas puff Z pinches on Z

Double-shell Ar gas puff implosions driven by 16.5 ± 0.5 MA on the Z generator at Sandia National Laboratories are very effective emitters of Ar K-shell radiation (photon energy >3 keV), producing yields of 330 ± 9% kJ [B. Jones et al., Phys. Plasmas 22, 020706 (2015)]. Previous simulations and experiments have reported dramatic increases in K-shell yields when adding an on-axis jet to double shell gas puffs for some configurations. We report on a series of experiments on Z testing Ar gas puff configurations with and without an on-axis jet guided by 3D magneto-hydrodynamic (MHD) simulations. Adding an on-axis jet was found to significantly improve the performance of some, but not all, configurations. The maximum observed K-shell yield of 375 ± 9% kJ was produced with a configuration that rapidly imploded onto an on-axis jet. A dramatic difference was observed in the plasma conditions at stagnation when a jet was used, producing a narrower stagnation column in experiments with a higher density but relatively lower electron temperature. The MHD simulations accurately reproduce the experimental measurements. The conversion efficiency for electrical energy delivered to the load to K-shell x-rays is estimated to be ∼12.5% for the best-performing configuration, similar to the best results from experiments at smaller facilities.

Complete mitochondrial genomes of Trisidos kiyoni and Potiarca pilula: Varied mitochondrial genome size and highly rearranged gene order in Arcidae.

We present the complete mitochondrial genomes (mitogenomes) of Trisidos kiyoni and Potiarca pilula, both important species from the family Arcidae (Arcoida: Arcacea). Typical bivalve mtDNA features were described, such as the relatively conserved gene number (36 and 37), a high A + T content (62.73% and 61.16%), the preference for A + T-rich codons, and the evidence of non-optimal codon usage. The mitogenomes of Arcidae species are exceptional for their extraordinarily large and variable sizes and substantial gene rearrangements. The mitogenome of T. kiyoni (19,614 bp) and P. pilula (28,470 bp) are the two smallest Arcidae mitogenomes. The compact mitogenomes are weakly associated with gene number and primarily reflect shrinkage of the non-coding regions. The varied size in Arcidae mitogenomes reflect a dynamic history of expansion. A significant positive correlation is observed between mitogenome size and the combined length of cox1-3, the lengths of Cytb, and the combined length of rRNAs (rrnS and rrnL) (P < 0.001). Both protein coding genes (PCGs) and tRNA rearrangements is observed in P. pilula and T. kiyoni mitogenomes. This analysis imply that the complicated gene rearrangement in mitochondrial genome could be considered as one of key characters in inferring higher-level phylogenetic relationship of Arcidae.

Impact of the clam Arca zebra artisanal fishery upon the population of the neogastropod Voluta musica in eastern Venezuela

120 An important ark clam ( Arca zebra ) artisanal fishery takes place in the east region of Venezuela. Besides the target species, trawling extracts a significant bycatch of several mollusk species including the gastropod Voluta musica, a threatened species according to the Venezuelan Red List of Endangered Species. In this paper we evaluate: 1) the composition of mollusk species in the bycatch, 2) the number of individuals of V. musica caught as bycatch and, 3) the abundance and size structure of the exploited population. Each fishing night, about 27,830 m2 are trawled by each boat extracting on the average 607 kg of A. zebra meat and 19 kg of V. musica (whole shelled animal). This fishery activity potentially captures ~30,000 kg of ark clam meat and 922 kg of V. musica in one week (~95 snails/fishing night/boat). The size structure of the V. musica population at the ark clam bed is significantly smaller than in other nearby sites not impacted by trawling fishing activities. Non-targeted species extracted in the bycatch but consumed by the local inhabitants include the gastropods Chicoreus brevifrons , Phyllonotus margaritensis , P. pomum , Fasciolaria tulipa , Strombus pugilis , a few Trochidae species, and the bivalves Pinctada imbricata , Spondylus americanus , Anadara floridana , A. notabilis , and Trachicardium muricatum . Individuals of V. musica along with several invertebrates are discarded. We recommend that V. musica should not be neglected as a conservation target, and despite that A. zebra fisheries are considered “artisanal”, that more strict regulations should be established on it. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Table Normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:Times New Roman,serif;}

남해안 패류양식장에서 분리한 Vibrio parahaemolyticus의 병원인자 분포 및 항균제 내성

From 2013 through 2015, we investigated the contamination status and antimicrobial resistance patterns of pathogenic Vibrio parahaemolyticus in commercially valuable seawater and shellfish (Oyster Crassostrea gigas, short-neck clam Venerupis philippinarum, ark shell Scapharca broughtonii and mussel Mytilus galloprovinciallis) from the southern coast of Korea. The detection rate of V. parahaemolyticus was highest in short-neck clams (23.7%), followed by ark shells (19.2%), oysters (15.9%), mussels (13.6%), and seawater (8.6%). The following percentages of PCR assays of shellfish were positive for the thermostable direct hemolysin-related hemolysin gene (trh) : oysters (12.8%), short-neck clams(11.8%), and ark shells (3.4%). Similar assays for the thermostable direct hemolysin gene (tdh) resulted in positive results for short-neck clams (5.9%) and ark shells (3.4%). Antimicrobial resistance was present in 100% of 8 tdh (+) and 2 trh (+) V. parahaemolyticus isolates challenged with ampicillin. However, all pathogenic V. parahaemolyticus were sensitive to 14 other antibiotics. To ensure the safety of shellfish consumption, the continuous monitoring of the prevalence and distribution of virulence factors of V. parahaemolyticus in shellfish farms is needed.