Japanese Scallop Patinopecten Yessoensis Research Articles

Effect of water mass mixing on phytoplankton dynamics in the scallop culture areas off Okhotsk Sea: A microcosm experiment

The nearshore (Soya Warm Water (SWW)) and offshore (Intermediate Cold Water (ICW) and Okhostk Sea Low Salinity Water (OSLSW)) waters in the Okhotsk Sea differ substantially in their physico-chemical characteristics. Thus, the extent to which water mass mixing impacts phytoplankton dynamics in the Japanese scallop Patinopecten yessoensis culture areas needs to be assessed to properly manage scallop stocks. This study examined the phytoplankton dynamics in nearshore (SWW) and offshore (ICW and OSLSW) waters and phytoplankton response to water mass mixing (SWW + ICW, OSLSW + ICW) for 5 days in spring (2007) and summer (2007–2009) microcosm experiments. Increased chlorophyll a concentration in ICW was observed due to higher nutrients available for phytoplankton uptake than in OSLSW and SWW at the start of each microcosm experiment. In comparison to spring microcosm, mixing of SWW + ICW promoted higher chlorophyll a concentration and faster Si(OH)4 utilization than in OSLSW + ICW in summer. In addition, the size structure of chlorophyll a differed from micro-size (>10μm) in SWW + ICW to nano-size (<10μm) chlorophyll a in OSLSW + ICW. Suspended particulate organic matter (SPOM) δ13C ratios were positively correlated with chlorophyll a in both mixed microcosms whereas SPOM δ15N isotopic ratios were inversely related to nitrate concentration in SWW + ICW, except in spring. This suggests that stable isotopes can be used in predicting phytoplankton biomass and nutrient utilization. In comparison to microcosm experiments, nearshore water column structure suggests vertical water mixing in summer to autumn when phytoplankton biomass and micro-size fraction were at maximum. Taken together, the advance of nutrient-rich ICW to nutrient-poor nearshore areas in the Okhotsk Sea resulted in increased chlorophyll a biomass and dominance of micro-size phytoplankton in summer, potentially enhancing nutrient and food supply to bottom-cultured scallops as suggested by both microcosm experiments and field observations.

An ecosystem model for estimating shellfish production carrying capacity in bottom culture systems

A production model has been developed to estimate scallop bottom culture carrying capacity. The model coupled pelagic system, scallop energetics and population dynamics with hydrodynamics. The methodology considers temperature and particle organic carbon (POC) were used to determine the carrying capacity through scallop growth, production and economic benefit. The model was applied to the Zhangzidao culture area in the North Yellow Sea, the largest marine ranching of Japanese scallops Patinopecten yessoensis in China. The studied area was divided into four boxes according to the temperature and depth gradients. The results showed that the model could successfully capture the main characteristics of the observed environmental variables, POC concentrations and biological behaviour of the cultured scallops. The food availability showed seasonal variations. The low temperature had also a great effect on the growth of the scallops in the south area during period of January to July. In contrary, the high temperature would cause high mortality rate of the scallops in the north area in September. Based on the production and profit, the optimal seeding densities were estimated to be 82,500, 105,000, 82,500, 60,000 in. ha−1, respectively in the Boxes1, 2, 3 and 4. There is the potential to increase the seeding density in the northeast area (Box 2), while the southwest area has already exceeded its capacity. The successful application of the model suggests that it could be used as a management tool for estimating the production carrying capacity in the bottom culture systems.

Anatomical Distribution of Diarrhetic Shellfish Toxins (DSTs) in the Japanese Scallop Patinopecten yessoensis and Individual Variability in Scallops and Mytilus edulis Mussels: Statistical Considerations.

Diarrhetic shellfish toxins (DSTs) are a group of phycotoxins that include okadaic acid (OA)/dinophysistoxin (DTX) analogues. At present, detailed data on the distribution of DST is insufficient, and studies of the appropriate sample sizes are lacking. This study investigated the DST frequency distribution in scallops and mussels by liquid chromatography-tandem mass spectrometry (LC/MS/MS) and a resampling analysis of existing data was carried out. The DST population-interval and the necessary sample size were also estimated. DSTs are localized in the scallop digestive-gland, and the DST concentrations in scallops were water-depth-dependent. DST concentrations in scallops and mussels showed normal distributions, but mussels tended to contain more DSTs than scallops. In the statistical resampling analysis of the acquired data on scallops and mussels, especially that using the bootstrap method, sample size was difficult to estimate when the DST variation was large. Although the DST population-interval could be statistically estimated from the sample standard deviation of three samples, the sample size corresponded to the risk management level, and the use of 13 or more samples was preferable. The statistical methods used here to analyze individual contents and estimate population content-intervals could be applied in various situations and for shellfish toxins other than DSTs.

Feeding of scallop mantle epithelial cell layer causes subacute toxicity against rodents

Japanese scallops Patinopecten yessoensis are one of the main marine products of Hokkaido, Japan. In addition to adductor muscle, scallop mantle tissue is also eaten in Japan. We fed Wistar rats diets containing the scallop mantle epithelial cell layer for 3–8 weeks and compared the outcomes with a control group. No differences in general appearance or behavior were observed between the groups for the first 2 weeks. Thereafter, a significant decrease in food consumption was observed, and the treated rats died between 6 and 8 weeks. Serum biochemistry and histological studies revealed nephrotoxicity and hepatotoxicity in rats fed scallop mantle epithelial cells. Glucose tolerance tests showed that feeding scallop mantle epithelial cells to rats causes a glucose metabolism disorder. A diet containing a water extract from scallop mantle epithelial cells caused toxicity in mice, but a diet containing a methanol extract, which dissolves diarrhetic shellfish poisoning (DSP) toxin, or an extract in heated 0.1 M HCl, which dissolves paralytic shellfish poisoning (PSP) toxin, did not cause toxicity. Mice fed a diet containing pronase-treated water extract neither showed a decrease in their food intake nor death. These results suggest that a water-soluble component other than DSP or PSP toxin causes toxicity.

Seasonal variability of Protoceratium reticulatum and yessotoxins in Japanese scallop Patinopecten yessoensis in northern Yellow Sea of China

This paper reports a toxic strain of Protoceratium reticulatum, its morphology, phylogeny, yessotoxins (YTXs) production and abundance in northern Yellow Sea of China from 2011 to 2015 was investigated. YTXs in hepatopancreas and edible parts of bottom sowing cultured Japanese scallop Patinopecten yessoensis in this sea area were determined weekly for 5 years. Other potential producers of YTXs, Gonyaulax spinifera and Lingulodinium polyedrum, were also investigated. Results revealed that Protoceratium reticulatum strain from the northern Yellow Sea belongs to a geographically widely distributed species. Motile cells of Protoceratium reticulatum contribute to YTXs in Japanese scallop, and G. spinifera may also be a potential contributor. Resting cysts of Protoceratium reticulatum, G. spinifera, and L. polyedrum in sediments were possibly important origins of YTXs in scallop cultured at sea bottom. YTXs in scallop decreased from 2011 to 2015, most toxins were concentrated in hepatopancreas, while a small portion in edible parts which was safe for consumption the whole year around.

A dynamic energy budget (DEB) growth model for Japanese scallop Patinopecten yessoensis cultured in China

A dynamic energy budget (DEB) growth model for Japanese scallop <i>Patinopecten yessoensis</i> cultured in China

Population-genetics analysis of the Japanese scallop Patinopecten yessoensis based on mitochondrial Cyt b gene

Population-genetics analysis of the Japanese scallop <i>Patinopecten yessoensis</i> based on mitochondrial Cyt <i>b</i> gene

Transcriptome analysis of male and female mature gonads of Japanese scallop Patinopecten yessonsis

The Japanese scallop Patinopecten yessoensis is an important commercial culture shellfish in China and Japan. In addition to its commercial interest, it has also attracted much attention because of its value in studying sex determination and differentiation mechanisms. Herein, two transcriptome libraries from male and female gonads at maturing stage were constructed. The two libraries were paired-end sequenced using Illumina sequencing techniques. A total of 81,986,898 cleaned reads were obtained, and assembled into 29,897 unigenes by using Trinity software and removing redundancy. Compared with the public Swiss-Prot and NR databases by BlastX, 9354 unigenes were significantly matched to known unique proteins. As determined by GO annotation and KEGG pathway mapping, functional annotation of the unigenes uncovered diverse biological functions and processes. After comparing the two transcriptome libraries, 8652 up-regulated and 2973 down-regulated genes were identified in the male gonads. According to annotation information, at least 30 genes related to sex determination and differentiation, such as Dmrt1, Sox9, fem1 and vasa, were identified and characterized. The expression patterns of the random eight genes were then validated by quantitative real-time PCR (qRT-PCR) suggesting the high reliability of RNA-Seq results. The study provides an archive for further studies of molecular mechanisms of bivalve sex determination and differentiation.

Microsatellite-centromere mapping in Japanese scallop (Patinopecten yessoensis) through half-tetrad analysis in gynogenetic diploid families

Gene-centromere mapping is an essential prerequisite for understanding the composition and structure of genomes. Half-tetrad analysis is a powerful tool for mapping genes and understanding chromosomal behavior during meiosis. The Japanese scallop (Patinopecten yessoensis), a cold-tolerant species inhabiting the northwestern Pacific coast, is a commercially important marine bivalve in Asian countries. In this study, inheritance of 32 informative microsatellite loci was examined in 70-h D-shaped larvae of three induced meiogynogenetic diploid families of P. yessoensis for centromere mapping using half-tetrad analysis. The ratio of gynogenetic diploids was proven to be 100%, 100% and 96% in the three families, respectively. Inheritance analysis in the control crosses showed that 51 of the 53 genotypic ratios observed were in accordance with Mendelian expectations at the 5% level after Bonferroni correction. Seven of the 32 microsatellite loci showed the existence of null alleles in control crosses. The second division segregation frequency (y) of the microsatellite loci ranged from 0.07 to 0.85 with a mean of 0.38, suggesting the existence of positive interference after a single chiasma formation in some chromosomes in the scallop. Microsatellite-centromere distances ranged from 4 cM to 42 cM under the assumption of complete interference. Information on the positions of centromeres in relation to the microsatellite loci will represent a contribution towards the assembly of genetic maps in the commercially important scallop species.

Depuration of paralytic shellfish toxins in Japanese scallop (Patinopecten yessoensis) in natural environment

To study the paralytic shellfish toxins (PSTs) depuration in Japanese scallop Patinopecten yessoensis in natural environment, Japanese scallops naturally contaminated with paralytic shellfish poisoning (PSP) toxins in the Dayao Bay in the northern Huanghai Sea are transited to Qipanmo waters in the Bohai Sea of no reported PSTs incidents. The levels and profile of PSTs during 30-day depuration are detected by the high performance liquid chromatography with fluorescence detection (HPLC-FLD). The results show that the toxicity of the PSTs in soft tissues decreases to a relatively low level at Day 9. Moreover, the depurated ratio at the early stage of the PSTs depuration is higher than that at the later stage. The toxicity analysis of dissected organs reveals that the digestive gland is the most contaminated PSTs part, which is of important implication for the human health and scallop aquiculture. The mortality of Japanese scallops during PSTs depuration experiment is relevant to PSTs level in the soft tissue.

Assimilation, Accumulation, and Metabolism of Dinophysistoxins (DTXs) and Pectenotoxins (PTXs) in the Several Tissues of Japanese Scallop Patinopecten yessoensis.

Japanese scallops, Patinopecten yessoensis, were fed with the toxic dinoflagellate Dinophysis fortii to elucidate the relative magnitude of assimilation, accumulation, and metabolism of diarrhetic shellfish toxins (DSTs) and pectenotoxins (PTXs). Three individual scallops were separately exposed to cultured D. fortii for four days. The average cell number of D. fortii assimilated by each individual scallop was 7.7 × 105. Dinophysistoxin-1 (DTX1), pectenotoxin-2 (PTX2) and their metabolites were analyzed by liquid chromatography tandem mass spectrometry (LC/MS/MS) and the toxin content in individual tissues (digestive gland, adductor muscle, gill, gonad, mantle, and the others), feces and the seawater medium were quantified. Toxins were almost exclusively accumulated in the digestive gland with only low levels being detected in the gills, mantles, gonads, and adductor muscles. DTX1 and PTX2 were the dominant toxins in the D. fortii cells fed to the scallops, whereas the dominant toxins detected in the digestive gland of scallops were PTX6 and esterified acyl-O-DTX1 (DTX3). In other tissues PTX2 was the dominant toxin observed. The ratio of accumulated to assimilated toxins was 21%–39% and 7%–23% for PTXs and DTXs respectively. Approximately 54%–75% of PTX2 and 52%–70% of DTX1 assimilated by the scallops was directly excreted into the seawater mainly without metabolic transformation.

Transcriptome sequencing and characterization of Japanese scallop Patinopecten yessoensis from different shell color lines.

Shell color is an important trait that is used in breeding the Japanese scallop Patinopecten yessoensis, the most economically important scallop species in China. We constructed four transcriptome libraries from different shell color lines of P. yessoensis: the left and right shell mantles of ordinary strains of P. yessoensis and the left shell mantles of the ‘Ivory’ and ‘Maple’ strains. These four libraries were paired-end sequenced using the Illumina HiSeq 2000 platform and contained 54,802,692 sequences, 40,798,962 sequences, 74,019,262 sequences, and 44,466,166 sequences, respectively. A total of 214,087,082 expressed sequence tags were assembled into 73,522 unigenes with an average size of 1,163 bp. When the data were compared against the public Nr and Swiss-Prot databases using BlastX, nearly 30.55% (22,458) of the unigenes were significantly matched to known unique proteins. Gene Ontology annotation and pathway mapping analysis using the Kyoto Encyclopedia of Genes and Genomes categorized unigenes according to their diverse biological functions and processes and identified candidate genes that were potentially involved in growth, pigmentation, metal transcription, and immunity. Expression profile analysis was performed on all four libraries and many differentially expressed genes were identified. In addition, 5,772 simple sequence repeats were obtained from the P. yessoensis transcriptomes, and 464,197, 395,646, and 310,649 single nucleotide polymorphisms were revealed in the ordinary strains, the ‘Ivory’ strain, and the ‘Maple’ strain, respectively. These results provide valuable information for future genomic studies on P. yessoensis and improve our understanding of the molecular mechanisms involved in the growth, immunity, shell coloring, and shell biomineralization of this species. These resources also may be used in a variety of applications, such as trait mapping, marker-assisted breeding, studies of population genetics and genomics, and work on functional genomics.

Comparison of the Internal Transcribed Spacer (ITS) Regions Between Hybrid and Their Parents in Scallop

The remarkable heterosis of the heterozygous F1 derived from Zhikong scallop Chlamys farreri (?) and Japanese scallop Patinopecten yessoensis (?) has been proved during cultured process, and some genetic characteristics analysis have also been conducted using some molecular markers ISSR, SSR, MSAP, and so on. However, no study about the comparison between hybrid offspring and parents based on the nuclear ribosomal DNA internal transcribed spacer (ITS) was explored. In this study, the ITS-1 and ITS-2 of the C. farreri, P. yessoensis and their hybrid were amplified by PCR using specific primers and characteristics of those ITS regions, genetic regularity were analyzed. The results suggested that ITS-2 (334 bp- 352 bp) were a little longer than ITS-1 (241 bp- 256 bp) in length while the average GC content were lower than AT in most individuals, and they all had high genetic variation. Also, the gene flow between the hybrid and female parents were higher than that of hybrid and male parents. Our data implied a commonality that the ITS regions of offspring shared more similarity with that of female parents. This data in the present investigation will help for further studies in heterosis mechanism and utilization of hybrid scallop in China.

Responses of scallop biodeposits to bioturbation by a deposit-feederApostichopus japonicus(Echinodermata: Holothuroidea): does the holothurian density matter?

The deposit-feeding holothurians can reduce the negative impact of bivalve farming by feeding and reworking bivalve wastes (biodeposits) in the context of co-culture. To test effects of the bioturbation by holothurians of different densities on bivalve wastes, a stocking density regime of the sea cucumber Apostichopus japonicus (35.4 ± 1.2 g, mean ± SE) was set at 0.0, 6.6, 13.2 ind m−2, and responses of the biotic parameters including chlorophyll a concentration (Chl. a), bacterial biomass and the abiotic ones as oxidation-reduction potential (ORP), organic matter (OM), organic carbon (OC), total nitrogen (TN) and organic phosphorus (OP) in biodeposits discharged by Japanese scallop Patinopecten yessoensis were investigated. Results showed that A. japonicus grew in a density-dependent manner, and the density-dependent effect on both biotic and abiotic parameters in biodeposits were also observed. Apostichopus japonicus stimulated a transfer process from reduction to weak reduction state of the biodeposits with a trend of higher density holothurians stimulating the process more. Furthermore, A. japonicus significantly controlled the bacterial abundance and Chl. a, as well as reducing the contents of OM, OC, TN and OP in the biodeposits. Yet, the response of abiotic parameters delayed rather than that of biotic parameters, underling the biotic parameters could be more sensitive to bioturbation than the abiotic ones. Our study suggests that the bioturbation of A. japonicus plays an important role in retarding organic waste accumulation and cleansing nutrients in bivalve farming wastes under co-culture condition and the bioremediation capacity may be closely dependent on its stocking density in practice.

Application of monoclonal antibody against granulocytes of scallop Chlamys farreri on granulocytes occurrence at different developmental stages and antigenic cross-reactivity of granulocytes in five other bivalve species

A monoclonal antibody (MAb) 6H7 raised specifically against granulocytes of scallop (Chlamys farreri) was employed to observe granulocyte occurrence successively in blastulae, gastrulae, trochophore larvae, D-shape larvae, umbo-veliger larvae and creeping larvae of C. farreri by immunohistochemistry assay contrasted with H&E stain using semi-thin sections. Moreover, the reactivity of the MAb with granulocytes of C. farreri, Bay scallop Argopecten irradians, Japanese scallop Patinopecten yessoensis, Blue mussel Mytilus edulis, Pacific oyster Crassostrea gigas and Manila clam Ruditapes philippinarum, was detected by immunofluorescence assay (IFA) with differential interference contrast and fluorescent microscopy and flow cytometric immunofluorescence assay (FCIFA). The results showed that positive signals were first observed at D-shape larval stage, about 28 h post fertilization, after that, umbo-veliger larvae exhibited the positive cells with a diameter of 3–5 μm distributed in velum, digestive gland and esophagus. Then in creeping larvae, the number of positive cells increased with average diameter of 5–7 μm, and widely distributed in foot, digestive gland, gills and adductor muscles. No positive signal was found in blastulae, gastrulae and trochophore larvae. The results of IFA and FCIFA showed MAb 6H7 reacted to granulocytes of C. farreri, A. irradians, P. yessoensis and C. gigas, and the positive percentage reactivity were 53 ± 2.5%, 15 ± 2.5%, 12 ± 2.1% and 19 ± 2.1%, respectively, however, no cross-reaction was detected in hemocytes of R. philippinarum and M. edulis.

35-Year Studies of Reproduction in Marine Invertebrates and the Influence of Climatic Factors on it

35-Year Studies of Reproduction in Marine Invertebrates and the Influence of Climatic Factors on it The studies of fouling of pioneer artificial substrates, conducted for the past 35 years near the coast of Primorsky Territory, Sea of Japan, Russia, have revealed an asynchronism in reproduction of invertebrates. Juveniles of Japanese scallop Patinopecten yessoensis and other widely distributed bivalves of boreal origin (Mytilus trossulus and Hiatella arctica) were, as a rule, abundant (over 250 scallops per a square meter of artificial substrate) in the odd-numbered years from 1977 to 1985. This is related mainly to the duration of ice season in previous winter, amount of precipitation, surface water salinity, and wind speed in June.

Clearance rates and ingestion efficiency of the Japanese scallop Patinopecten yessoensis

Clearance rates and ingestion efficiency of the Japanese scallop Patinopecten yessoensis

Characteristics of minerals extracted from the mid-gut gland of Japanese scallop Patinopecten yessoensis at various pH values

This experiment was carried out to determine the proximate composition of the mid-gut gland (MGG) of the Japanese scallop Patinopecten yessoensis to evaluate the characteristics of divalent minerals and water-soluble protein at various pHs, and to examine Cd-binding protein at different molecular weights. MGG of scallop contained protein, fat and ash of 28.9 g/100 g dry matter, 44.6 g/100 g dry matter and 6.78 g/100 dry matter, respectively. MGG also contained the macrominerals sodium, potassium, magnesium and calcium, and the trace minerals iron, zinc, cadmium and copper. The solubility of divalent minerals and water-soluble protein was high in both acidic and alkaline conditions, except that magnesium was not affected by acidity. The solubility of copper and iron had a positive correlation with water-soluble protein at all pH values, whereas cadmium had a strong correlation at alkaline pH. Low-molecular-weight water-soluble protein (fraction III, 437.5 < MW < 1,355) bound cadmium strongly in acidic, neutral and alkaline conditions. However, in acidic conditions cadmium had the strongest binding to protein.

Haplosporidium nelsoni (MSX) in Japanese scallops Patinopecten yessoensis (Jay, 1857) from Dalian along the northern coast of the Yellow Sea, China

The protozoan parasite Haplosporidium nelsoni (MSX) was identified in Japanese scallops Patinopecten yessoensis (Jay, 1857) from Dalian along the northern coast of the Yellow Sea, China by histopathologic examination, polymerase chain reaction (PCR) amplification, and in situ hybridization (ISH) assay. H. nelsoni plasmodia-like structures were identified in the digestive glands of scallops by histologic examination, but no parasite spores were observed. PCR using the Hap-F2, R2 primer pair produced a sequence with 100% homology with the corresponding small subunit rDNA region of H. nelsoni. An ISH assay using the oligonucleotide probe MSX1347 produced a positive reaction with the Japanese scallop parasite. This is the first report of H. nelsoni in P. yessoensis in China.

Evaluation of the Possibility That Free Fatty Acids Cause False-Positive Result in Diarrhetic Shellfish Poisoning Mouse Bioassay in Actual Use

Midgut glands of bivalves are used for the mouse bioassay of diarrhetic shellfish poison (DSP). A large quantity of free fatty acids (FFAs) causes a false positive outcome in the assay. To examine whether this is likely to occus under conditions of actual use, we analyzed the contents of the FFAs in the enlarged midgut glands during gametogenesis of Japanese scallops Patinopecten yessoensis that had been caught at two points in Hunka Bay on March 27, 2006, because the content of FFAs may increase with activation of lipogenesis for gametogenesis. Fatty acids (FAs) were measured with fluorometric high-performance liquid chromatography after derivatization with 9-anthryldiazomethane. The total FFAs (14 : 0, 16 : 0, 18 : 0, 16 : 1, 18 : 1, 18 : 4, 20 : 5 and 22 : 6) represented 3.3-4.2 wt% of the lipid. The toxic FFAs accounted for 40-43 wt% of the total FFAs. Content of each FFA (18 : 1, 2.7-5.0 mg/g lipid; 18 : 4, tr.-2.0 mg/g; 20 : 4, n.d.; 20 : 5, 8.0-9.1 mg/g and 22 : 6, 2.0-2.1 mg/g) was lower than the lethal dose tentatively calculated from the relative toxicity. It appears that the likelihood of FFAs causing false-positives in the mouse bioassay is low if the sample is fresh and is extracted immediately after homogenizing.