Heterosis has been exploited to enhance the yield and adaptability in various shellfish species;however,the molecular basis of it remains unclear.The Pacific oyster Crassostrea gigas is one of the most economically im...Heterosis has been exploited to enhance the yield and adaptability in various shellfish species;however,the molecular basis of it remains unclear.The Pacific oyster Crassostrea gigas is one of the most economically important aquaculture species,and its productive traits can be improved by hybridization.Here,an intraspecific cross between orange shell(O,10th generation)and‘Haida No.1’(H,13th generation)of C.gigas was performed to assess the heterosis of survival trait.Survival rates of hybrid family(OH)and inbred families(HH and OO)were compared at larval stage,and eyed-pediveliger larvae of three families were subjected to transcriptome analysis.The analysis results of best-parent heterosis and mid-parent heterosis showed that the hybrid family exhi-bited a high heterosis in survival relative to the parental families.The OH-M(OH vs.OO)and OH-P(OH vs.HH)had 425 and 512 dif-ferentially expressed genes(DEGs),respectively.Functional enrichment analysis of these DEGs revealed that the significantly enrich-ed genes function in virion binding,C-type lectin receptor signaling pathway,cellular defense response and other immune-related pro-cesses,which involves perlucin-like protein,CD209 antigen-like protein,ZNFX1,caspase-3 and acan genes.These differentially ex-pressed genes in OH-M and OH-P,together with the immune-related processes mentioned above may play an important role in the larval survival of C.gigas.In addition,three genes(CYP450,fucolectin and perlucin-like)are associated with the orange shell and low survival of maternal oyster OO.These findings provide support for the application of hybrid with superior survival and will facilitate the understanding of heterosis formation in the Pacific oyster.展开更多
The color of Mollusca shells is one of the most important attributes to consumers.At the cellular level,black color is mainly from the melanin produced by melanocytes.The melanosome is a specialized membrane-bound org...The color of Mollusca shells is one of the most important attributes to consumers.At the cellular level,black color is mainly from the melanin produced by melanocytes.The melanosome is a specialized membrane-bound organelle that is involved in melanin synthesis,storage,and transportation.How the complex pigmentation process in the Crassostrea gigas is established remains an open question.The objectives of this studies are to examine the morphological characteristics of melanosomes or melanin of mantle pigmentation in the Pacific oyster,thereby investigating its contribution to shell color.The results show that pigmented granules of the mantles vary among the three lobes,and the melanosomes at different stages are enriched in distinct cargo molecules,which indicate the remarkable difference between the marginal mantle and central mantle.Examination of mantle histology reveals that the mantle margin of the oyster is characterized by three different folds,including the outer secretory,middle sensory,and inner muscular fold.Ferrous ion chelating assays against the tyrosine hydroxylase indicate that a large amount of melanin is localized in the inner surface of the middle fold.Transmission electron microscopy analyses show that the mantle edge is composed of tall columnar and cuboidal epidermal cells and some pigmented melanocytes intersperse among these cells.The numbers of melanosomes among the three lobes are different.In the inner fold and the middle fold of the mantle,some single dispersion,or aggregation of melanosomes with different degrees of melanization are found in the outer surface.Numerous melanosomes are distributed in the epithelium of the outer fold of the mantle,and mainly are at the apical microvillar surface near the lumen.However,melanosomes are occasionally observed in the central mantle,and they are relatively less.This work provides new insights into the process of melanin deposit in the mantle and shell pigmentation in C.gigas.展开更多
In order to evaluate the effects of triploidy induction on a selected strain‘Haida No.2’of the Pacific oyster Crassostrea gigas,which is characterized with golden shell color and high growth rate,the growth,survival...In order to evaluate the effects of triploidy induction on a selected strain‘Haida No.2’of the Pacific oyster Crassostrea gigas,which is characterized with golden shell color and high growth rate,the growth,survival rate and stability of triploid rate were analyzed at different development stages in the present study.Three different conditions inhibiting the release of polar body Ⅱ or polar body Ⅰ were tested:(A)Cytochalasin-B(CB),0.5mg L^(−1) at 10min post-insemination for 15 min;(B)CB,0.5mg L^(−1)at 15 min postinsemination for 20 min;and(C)CB,0.7mg L^(−1),at 15 min post-insemination for 20 min.The triploidy induction treatments significantly reduced the D-larvae and survival rates at the larvae stage but not at the juvenile and adult stages.Triploid rate dramatically decreased at the larval stage and did not significantly change at the juvenile and adult stages.Regarding the stability of the triploid rate,there was a significant difference between the three treatment groups.Larvae from the treatment A and control groups exhibited higher growth rates in shell height than those from the other two treatment groups at day 27.Triploid juveniles and adults from the treatment A group exhibited a higher wet weight than diploids from the control group and triploids from the other treatment groups.Triploidy induction did not affect the shell color of the progeny.The results obtained in the study demonstrate that triploidy induction has the potential to be used to increase the production of C.gigas variety‘Haida No.2’without modifying its golden shell color.展开更多
Glycogen,amino acids,fatty acids,and other nutrient components affect the flavor and nutritional quality of oysters.Methods based on near-infrared reflectance spectroscopy(NIRS)were developed to rapidly and proximatel...Glycogen,amino acids,fatty acids,and other nutrient components affect the flavor and nutritional quality of oysters.Methods based on near-infrared reflectance spectroscopy(NIRS)were developed to rapidly and proximately determine the nutrient content of the Pacific oyster Crassostreagigas.Samples of C.gigas from 19 costal sites were freeze-dried,ground,and scanned for spectral data collection using a Fourier transform NIR spectrometer(Thermo Fisher Scientific).NIRS models of glycogen and other nutrients were established using partial least squares,multiplication scattering correction first-order derivation,and Norris smoothing.The R_(C) values of the glycogen,fatty acids,amino acids,and taurine NIRS models were 0.9678,0.9312,0.9132,and 0.8928,respectively,and the residual prediction deviation(RPD)values of these components were 3.15,2.16,3.11,and 1.59,respectively,indicating a high correlation between the predicted and observed values,and that the models can be used in practice.The models were used to evaluate the nutrient compositions of 1278 oyster samples.Glycogen content was found to be positively correlated with fatty acids and negatively correlated with amino acids.The glycogen,amino acid,and taurine levels of C.gigas cultured in the subtidal and intertidal zones were also significantly different.This study suggests that C.gigas NIRS models can be a cost-effective alternative to traditional methods for the rapid and proximate analysis of various slaughter traits and may also contribute to future genetic and breeding-related studies in Pacific oysters.展开更多
A variety of shell colors are one of the most fundamental characteristics of molluscs,which have importantly ecological and economic signifi cance.The Pacifi c oyster Crassostrea gigas is distributed in many sea areas...A variety of shell colors are one of the most fundamental characteristics of molluscs,which have importantly ecological and economic signifi cance.The Pacifi c oyster Crassostrea gigas is distributed in many sea areas around the world and also an aquacultured mollusc with high nutritional value.In this study,the whole soft body and the mantle tissue of black-shelled Pacifi c oyster(BSO)and white-shelled Pacifi c oyster(WSO)with starkly diff erent melanin contents were compared,and the diff erences in physiology and metabolism between BSO and WSO were analyzed.The results of physiological indicators suggested BSO show more melanin,more dry matter,more crude lipid content,and stronger ability to scavenge free radicals than WSO.The altered metabolites of glycerophospholipids,fatty acyls,and steroids revealed diff erent regulatory mechanisms of lipids.The correlation analysis of metabolomics and previously published RNAseq data suggested that BSO and WSO mainly diff ered in the basal metabolic processes,such as lipid,amino acid and purine metabolisms.This study provides insights into the changes in the physiological indictors and the metabolites of oysters with varying melanin content.展开更多
Polyploid breeding is widely used in various marine species. Low salinity treatment is an effective method of inducing triploid of bivalve mollusks. In this study, RNA-seq was performed to determine genes and pathways...Polyploid breeding is widely used in various marine species. Low salinity treatment is an effective method of inducing triploid of bivalve mollusks. In this study, RNA-seq was performed to determine genes and pathways involved in hyposaline adaption and cell division of Pacific oyster(Crassostrea gigas) zygotes, trying to better understand the possible molecular mechanism of hypo-osmotic induction. A total of 26965 unigenes were generated in the de novo assembly of clean Illumina reads with an average length of 934 bp and N50 of 1721 bp. Of 3024 differentially expressed genes(DEGs), 2501 were up-regulated and 523 were downregulated. GO(Gene Ontology) annotation and KEGG(Kyoto Encyclopedia of Genes and Genomes) pathway analysis of these DEGs revealed that these DEGs participate a variety of biological processes including osmoregulation, cytoskeleton organization, cell survival and death, and substantially modulate cell proliferation and embryonic development. In summery, RNA-seq methodology was applied for the first time to demonstrate hypotonic-induced transcriptomic alteration in oyster zygotes. Our findings not only interpreted the relatively high mortality of induced larvae, but also provided a valuable reference for further investigations on the mechanism of hyposaline induction, thus should aid to the application of low salinity in triploid induction in large scale aquaculture in future.展开更多
The Pacific oyster Crassostrea gigas is one of the most widely cultivated aquaculture species and contributes signifi-cantly to total seafood production for human beings.However,mass mortality occurred frequently,and ...The Pacific oyster Crassostrea gigas is one of the most widely cultivated aquaculture species and contributes signifi-cantly to total seafood production for human beings.However,mass mortality occurred frequently,and in some regions almost all oysters died during seed production and grow-out stage.In order to explore whether hybridization breeding can improve its growth and survival,a complete diallel cross between a selected strain‘Haida No.1’(S)and an orange shell variant(O)of C.gigas was carried out.The larval growth and survival were compared among hybrids and purebred strains at temperatures of 16,20,24,28 and 32℃;salinities of 15,20,25,30 and 35;and stocking densities of 0.5,1,2,4 and 8 larvae mL−1.Under different environments,the hybridization between two strains of C.gigas showed the heterosis of growth and survival.The mean shell height and survival rate of the two reciprocal crosses(OS,SO)were significantly higher than those of the two purebred strains(SS,OO)under all environ-mental conditions.In particular,OS showed greater heterosis than the purebred strains and SO progeny.The results showed that the productive traits of the‘Haida No.1’could be improved by crossing with the orange shell line.Meanwhile,the results from this study also indicated that hybridization between the two strains of C.gigas may be a promising way for breeding new variety with high survival rate.展开更多
The Ras gene,a conserved member of the insulin pathway,andβ-glucosidase gene,an important cellulase,are two important growth-related genes.However,there is no study on the association between mutations of these two g...The Ras gene,a conserved member of the insulin pathway,andβ-glucosidase gene,an important cellulase,are two important growth-related genes.However,there is no study on the association between mutations of these two genes and growth traits in bivalves.Here,the polymorphism of these two genes in Crassostrea gigas were revealed.Their association with growth traits was evaluated in 290 oysters from five families,and was further confirmed in another 186 oysters from three fast-growing strains.Seventeen and twelve SNPs were identified in the Ras gene andβ-glucosidase gene,respectively.Among these SNPs,four SNPs in each gene(Ras:C.86C>A,C.90T>C,C.112A>G and C.118G>A;β-glucosidase:C.247G>A,C.284C>T,C.1260C>T and C.1293T>C)were significantly(P<0.05)associated with the growth of these oysters.Furthermore,eight and nine haplotypes were constructed in the Ras gene andβ-glucosidase gene,respectively.Oysters with both haplotypes R-Hap5(CCAA)andβ-Hap7(ACCT),or with both R-Hap 6(ATGG)andβ-Hap 6(ACTC),or with both R-Hap 6 andβ-Hap 9(ACTT),or with both R-Hap 7(ATAA)andβ-Hap 7,showed the highest growth performances.These results provide candidate markers for selecting C.gigas with fast growth.展开更多
Shell color is regarded as an economic trait in many breeding programs of bivalve mollusks,but the relationship between shell color and production traits remains controversial.In our breeding program of Crassostrea gi...Shell color is regarded as an economic trait in many breeding programs of bivalve mollusks,but the relationship between shell color and production traits remains controversial.In our breeding program of Crassostrea gigas,solid white,black,and orange shell lines were obtained,and second-generation(F2)and testcross families with segregating shell colors were constructed by crossing these three lines.These segregating families provided ideal samples for investigating the relationship between shell color and production traits in C.gigas.The growth and survival of 7-month-old oysters with different shell colors sampled within the same families were compared in seven F2 families and 13 testcrosses.In addition,the growth and survival of oysters from the three shell color lines were compared at 4 and 16 months of age.The growth and survival rates of the orange shell line were significantly lower than those of the white and black shell lines.However,no significant difference in growth between oysters with different shell colors was observed within segregating families,except the testcrosses produced by crossing orange-and white-shelled grandparents,and no significant difference in survival was observed in any family.Overall,no significant correlation was observed between shell color and production traits in C.gigas.These results suggest that shell color cannot be used as a marker to guide the selection of growth and survival traits.Thus shell color and production traits should be selected independently in oyster breeding programs.展开更多
Caspase-8,first classified as a pro-apoptotic caspase,is considered to have arisen from duplication with caspase-10 and involves multiple immune and inflammatory responses in mammals.However,few are known on the phylo...Caspase-8,first classified as a pro-apoptotic caspase,is considered to have arisen from duplication with caspase-10 and involves multiple immune and inflammatory responses in mammals.However,few are known on the phylogeny and function of caspase-8 in molluscs,one of the largest phyla in marine invertebrates.In this study,we conducted phylogenetic and functional analysis on molluscan caspase-8-like genes.Results indicate that duplication occurred in molluscan caspase-8-like genes,resulting in at least two caspase-8 copies in some groups of bivalves.Additional studies in Pacific oyster Crassostrea gigas showed different spatio-temporal expression patterns and subcellular localizations of CgCaspase-8-1 and CgCaspase-8-2.While no interaction was observed between CgCaspase-8-2 and CgFADD,the adaptor molecule in apoptosis,yeast two-hybrid and co-immunoprecipitation assays suggested the interaction between CgCaspase-8-1 and CgFADD,indicating its pro-apoptotic function.In addition,CgCaspase-8-1 showed interaction with the CARD domain of CgRIG-I.Together with two NF-κB subunits(Cgp105 and CgRel),their transcripts were up-regulated in response to poly(I:C)stimuli,supporting the immune function of both pro-and anti-inflammation.The results provide insight into the evolution and functional diversification of Bivalvia caspase-8 genes.展开更多
Synonymous codons have different frequencies of usage in many species.Based on the frequency of usage,the codons can be divided into two groups,rare codons and abundant codons.Rare codons are found to be enriched at t...Synonymous codons have different frequencies of usage in many species.Based on the frequency of usage,the codons can be divided into two groups,rare codons and abundant codons.Rare codons are found to be enriched at the start regions of genes,and it is assumed that these codons can reduce elongation speed of genes.However,the rare codon usage in different genomic regions of mollusks and their relationship with selective pressure has not been systematically investigated.In this study,the patterns of rare codon usage are characterized at whole genome level,and their relationship with selective pressures is investigated in Crassostrea gigas.The rare codons are enriched at the start regions of genes with high and medium expression levels,and their proportion is higher than those in the genes with low expression level.The genes with longer coding sequences and more exon numbers have lower fraction of rare codons at start regions.Rare codons have lower level of nucleotide diversity and higher frequency of rare mutations at start regions.This work is the first comprehensive investigation of the relationships between rare codon usage and some intrinsic genetic factors in mollusca species.The results suggest that the selective pressures play an important role in shaping the rare codon usage in the C.gigas genome.展开更多
There is an increasing interest in discovering new antibacterial agents derived from nature to enhance the treatment of various bacterial infections.Defensins and their derived peptide fragments exhibit significant an...There is an increasing interest in discovering new antibacterial agents derived from nature to enhance the treatment of various bacterial infections.Defensins and their derived peptide fragments exhibit significant antibacterial activity without any cytotoxic effects,making them attractive features for potential novel antibacterial therapeutics.Crassostrea gigas,a traditional seafood that has been used worldwide for centuries,has its shells applied in Chinese medicine as Ostreae concha.In this study,bioinformatics analysis was used to obtain a novel antibacterial peptide,CGD-1,derived from marine Chinese medicine Ostreae concha.The physicochemical characterization and circular dichroism analysis results demonstrated that CGD-1 assembled into anα-helical structure in a simulated membrane environment,and it displayed antibacterial action against Gram-negative bacteria.The minimal inhibitory concentrations against both Pseudomonas aeruginosa ATCC27853 and Escherichia coli ATCC25922 were 25μM.CGD-1 was able to efficiently permeate the cell membrane.Changes in bacterial cell morphology were evaluated using a field emission scanning electron microscope.The results suggested that CGD-1 exerted its antibacterial activity through permeabilizing and disrupting the bacterial cell membrane.Therefore,CGD-1 may have potential applications in fighting against pathogenic bacteria such as P.aeruginosa and E.coli.展开更多
Integrated Multi-Trophic Aquaculture(IMTA)is an effective method for sustainable aquaculture as species from different trophic levels could reduce negative effects from fed species in the environment.A proper proporti...Integrated Multi-Trophic Aquaculture(IMTA)is an effective method for sustainable aquaculture as species from different trophic levels could reduce negative effects from fed species in the environment.A proper proportion of different trophic species in an IMTA system could improve the aquaculture production and environmental sustainability.At present,research on the proper proportions for farming species is scarce.We investigated the effects of IMTA modes of oyster(Crassostrea gigas)and kelp(Saccharina japonica)in different weight ratios on water quality and carbonate system in a closed enclosure experiment for three days in the Sanggou Bay in Shandong Province,China,in December 2017.Nine collocation modes in oyster:kelp weight ratio were tested showing as 24:3,24:2,24:1,16:3,16:2,16:1,8:3,8:2,and 8:1.The water parameters were determined at 17:00 on Day 1(D1),and 6:00 and 17:00 on Days 2(D2)and 3(D3).As two-way ANOVA showed,all increased parameters(dissolved oxygen(DO),pH,chl a,the carbonate system and pCO2)were significantly related to oyster-kelp modes,and interaction between modes and time were also significant(P<0.05).On the 3th day,the 8:3 mode was the highest in DO,pH,chl a,CO32-(P<0.05),and dissolved inorganic carbon(DIC),HCO3-,CO2,and pCO2 were the lowest(P<0.05).According to previous references and the results of this study,the appropriate oyster:kelp proportion at the beginning of winter is from 8:2 to 8:3.The results of this study may help government to optimize the aquaculture structure of Sanggou Bay.展开更多
基金supported by the grants from the China Agriculture Research System Project(No.CARS-49)the Earmarked Fund for Agriculture Seed Improvement Project of Shandong Province(No.2020LZGC016).
文摘Heterosis has been exploited to enhance the yield and adaptability in various shellfish species;however,the molecular basis of it remains unclear.The Pacific oyster Crassostrea gigas is one of the most economically important aquaculture species,and its productive traits can be improved by hybridization.Here,an intraspecific cross between orange shell(O,10th generation)and‘Haida No.1’(H,13th generation)of C.gigas was performed to assess the heterosis of survival trait.Survival rates of hybrid family(OH)and inbred families(HH and OO)were compared at larval stage,and eyed-pediveliger larvae of three families were subjected to transcriptome analysis.The analysis results of best-parent heterosis and mid-parent heterosis showed that the hybrid family exhi-bited a high heterosis in survival relative to the parental families.The OH-M(OH vs.OO)and OH-P(OH vs.HH)had 425 and 512 dif-ferentially expressed genes(DEGs),respectively.Functional enrichment analysis of these DEGs revealed that the significantly enrich-ed genes function in virion binding,C-type lectin receptor signaling pathway,cellular defense response and other immune-related pro-cesses,which involves perlucin-like protein,CD209 antigen-like protein,ZNFX1,caspase-3 and acan genes.These differentially ex-pressed genes in OH-M and OH-P,together with the immune-related processes mentioned above may play an important role in the larval survival of C.gigas.In addition,three genes(CYP450,fucolectin and perlucin-like)are associated with the orange shell and low survival of maternal oyster OO.These findings provide support for the application of hybrid with superior survival and will facilitate the understanding of heterosis formation in the Pacific oyster.
基金supported by grants from the National Natural Science Foundation of China(Nos.31772843 and 31972789)the National Key R&D Program of China(No.2018YFD0900200)+1 种基金the Earmarked Fund for Agriculture Seed Improvement Project of Shandong Province(No.2017LZGC009)the Ocean University of China-Auburn University Joint Research Center for Aquaculture and Environmental Science。
文摘The color of Mollusca shells is one of the most important attributes to consumers.At the cellular level,black color is mainly from the melanin produced by melanocytes.The melanosome is a specialized membrane-bound organelle that is involved in melanin synthesis,storage,and transportation.How the complex pigmentation process in the Crassostrea gigas is established remains an open question.The objectives of this studies are to examine the morphological characteristics of melanosomes or melanin of mantle pigmentation in the Pacific oyster,thereby investigating its contribution to shell color.The results show that pigmented granules of the mantles vary among the three lobes,and the melanosomes at different stages are enriched in distinct cargo molecules,which indicate the remarkable difference between the marginal mantle and central mantle.Examination of mantle histology reveals that the mantle margin of the oyster is characterized by three different folds,including the outer secretory,middle sensory,and inner muscular fold.Ferrous ion chelating assays against the tyrosine hydroxylase indicate that a large amount of melanin is localized in the inner surface of the middle fold.Transmission electron microscopy analyses show that the mantle edge is composed of tall columnar and cuboidal epidermal cells and some pigmented melanocytes intersperse among these cells.The numbers of melanosomes among the three lobes are different.In the inner fold and the middle fold of the mantle,some single dispersion,or aggregation of melanosomes with different degrees of melanization are found in the outer surface.Numerous melanosomes are distributed in the epithelium of the outer fold of the mantle,and mainly are at the apical microvillar surface near the lumen.However,melanosomes are occasionally observed in the central mantle,and they are relatively less.This work provides new insights into the process of melanin deposit in the mantle and shell pigmentation in C.gigas.
基金supported by the grants from the China Agriculture Research System Project(No.CARS-49)the Earmarked Fund for Agriculture Seed Improvement Project of Shandong Province(Nos.2020LZGC016,2021 LZGC027).
文摘In order to evaluate the effects of triploidy induction on a selected strain‘Haida No.2’of the Pacific oyster Crassostrea gigas,which is characterized with golden shell color and high growth rate,the growth,survival rate and stability of triploid rate were analyzed at different development stages in the present study.Three different conditions inhibiting the release of polar body Ⅱ or polar body Ⅰ were tested:(A)Cytochalasin-B(CB),0.5mg L^(−1) at 10min post-insemination for 15 min;(B)CB,0.5mg L^(−1)at 15 min postinsemination for 20 min;and(C)CB,0.7mg L^(−1),at 15 min post-insemination for 20 min.The triploidy induction treatments significantly reduced the D-larvae and survival rates at the larvae stage but not at the juvenile and adult stages.Triploid rate dramatically decreased at the larval stage and did not significantly change at the juvenile and adult stages.Regarding the stability of the triploid rate,there was a significant difference between the three treatment groups.Larvae from the treatment A and control groups exhibited higher growth rates in shell height than those from the other two treatment groups at day 27.Triploid juveniles and adults from the treatment A group exhibited a higher wet weight than diploids from the control group and triploids from the other treatment groups.Triploidy induction did not affect the shell color of the progeny.The results obtained in the study demonstrate that triploidy induction has the potential to be used to increase the production of C.gigas variety‘Haida No.2’without modifying its golden shell color.
基金Supported by the Shandong Province Key R&D Program Project(No.2021LZGC029)the Major Scientific and Technological Innovation Project of Shandong Province(No.2019JZZY010813)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA24030105)the Qingdao Key Technology and Industrialization Demonstration Project(No.22-3-3-hygg-2-hy)the Earmarked Fund for China Agriculture Research System(No.CARS-49)。
文摘Glycogen,amino acids,fatty acids,and other nutrient components affect the flavor and nutritional quality of oysters.Methods based on near-infrared reflectance spectroscopy(NIRS)were developed to rapidly and proximately determine the nutrient content of the Pacific oyster Crassostreagigas.Samples of C.gigas from 19 costal sites were freeze-dried,ground,and scanned for spectral data collection using a Fourier transform NIR spectrometer(Thermo Fisher Scientific).NIRS models of glycogen and other nutrients were established using partial least squares,multiplication scattering correction first-order derivation,and Norris smoothing.The R_(C) values of the glycogen,fatty acids,amino acids,and taurine NIRS models were 0.9678,0.9312,0.9132,and 0.8928,respectively,and the residual prediction deviation(RPD)values of these components were 3.15,2.16,3.11,and 1.59,respectively,indicating a high correlation between the predicted and observed values,and that the models can be used in practice.The models were used to evaluate the nutrient compositions of 1278 oyster samples.Glycogen content was found to be positively correlated with fatty acids and negatively correlated with amino acids.The glycogen,amino acid,and taurine levels of C.gigas cultured in the subtidal and intertidal zones were also significantly different.This study suggests that C.gigas NIRS models can be a cost-effective alternative to traditional methods for the rapid and proximate analysis of various slaughter traits and may also contribute to future genetic and breeding-related studies in Pacific oysters.
基金Supported by the Agricultural Variety Improvement Project of Shandong Province(No.2019LZGC020),the National Natural Science Foundation of China(Nos.41906088,41876193,31802328)the National Key R&D Program of China(No.2018YFD0901400)+2 种基金the Special Funds for Taishan Scholars Project of Shandong Province,China(No.tsqn201812094)the Shandong Provincial Natural Science Foundation,China(No.ZR2019MC002),the Modern Agricultural Industry Technology System of Shandong Province,China(No.SDAIT-14-03)the Plan of Excellent Youth Innovation Team of Colleges and universities in Shandong Province,China(No.2019KJF004)。
文摘A variety of shell colors are one of the most fundamental characteristics of molluscs,which have importantly ecological and economic signifi cance.The Pacifi c oyster Crassostrea gigas is distributed in many sea areas around the world and also an aquacultured mollusc with high nutritional value.In this study,the whole soft body and the mantle tissue of black-shelled Pacifi c oyster(BSO)and white-shelled Pacifi c oyster(WSO)with starkly diff erent melanin contents were compared,and the diff erences in physiology and metabolism between BSO and WSO were analyzed.The results of physiological indicators suggested BSO show more melanin,more dry matter,more crude lipid content,and stronger ability to scavenge free radicals than WSO.The altered metabolites of glycerophospholipids,fatty acyls,and steroids revealed diff erent regulatory mechanisms of lipids.The correlation analysis of metabolomics and previously published RNAseq data suggested that BSO and WSO mainly diff ered in the basal metabolic processes,such as lipid,amino acid and purine metabolisms.This study provides insights into the changes in the physiological indictors and the metabolites of oysters with varying melanin content.
基金supported by the National Natural Science Foundation of China (No. 31172403)。
文摘Polyploid breeding is widely used in various marine species. Low salinity treatment is an effective method of inducing triploid of bivalve mollusks. In this study, RNA-seq was performed to determine genes and pathways involved in hyposaline adaption and cell division of Pacific oyster(Crassostrea gigas) zygotes, trying to better understand the possible molecular mechanism of hypo-osmotic induction. A total of 26965 unigenes were generated in the de novo assembly of clean Illumina reads with an average length of 934 bp and N50 of 1721 bp. Of 3024 differentially expressed genes(DEGs), 2501 were up-regulated and 523 were downregulated. GO(Gene Ontology) annotation and KEGG(Kyoto Encyclopedia of Genes and Genomes) pathway analysis of these DEGs revealed that these DEGs participate a variety of biological processes including osmoregulation, cytoskeleton organization, cell survival and death, and substantially modulate cell proliferation and embryonic development. In summery, RNA-seq methodology was applied for the first time to demonstrate hypotonic-induced transcriptomic alteration in oyster zygotes. Our findings not only interpreted the relatively high mortality of induced larvae, but also provided a valuable reference for further investigations on the mechanism of hyposaline induction, thus should aid to the application of low salinity in triploid induction in large scale aquaculture in future.
基金supported by the National Natural Science Foundation of China (Nos. 31972789 and 31772843)the Industrial Development Project of Qingdao City (No. 20-3-4-16-nsh)the Science and Technology Development Project of Weihai City (No. 2018NS01)
文摘The Pacific oyster Crassostrea gigas is one of the most widely cultivated aquaculture species and contributes signifi-cantly to total seafood production for human beings.However,mass mortality occurred frequently,and in some regions almost all oysters died during seed production and grow-out stage.In order to explore whether hybridization breeding can improve its growth and survival,a complete diallel cross between a selected strain‘Haida No.1’(S)and an orange shell variant(O)of C.gigas was carried out.The larval growth and survival were compared among hybrids and purebred strains at temperatures of 16,20,24,28 and 32℃;salinities of 15,20,25,30 and 35;and stocking densities of 0.5,1,2,4 and 8 larvae mL−1.Under different environments,the hybridization between two strains of C.gigas showed the heterosis of growth and survival.The mean shell height and survival rate of the two reciprocal crosses(OS,SO)were significantly higher than those of the two purebred strains(SS,OO)under all environ-mental conditions.In particular,OS showed greater heterosis than the purebred strains and SO progeny.The results showed that the productive traits of the‘Haida No.1’could be improved by crossing with the orange shell line.Meanwhile,the results from this study also indicated that hybridization between the two strains of C.gigas may be a promising way for breeding new variety with high survival rate.
基金the National Natural Sci-ence Foundation of China(No.31972789)the Industrial Development Project of Qingdao City(No.20-3-4-16-nsh)the Science and Technology Development Pro-ject of Weihai City(No.2018NS01).
文摘The Ras gene,a conserved member of the insulin pathway,andβ-glucosidase gene,an important cellulase,are two important growth-related genes.However,there is no study on the association between mutations of these two genes and growth traits in bivalves.Here,the polymorphism of these two genes in Crassostrea gigas were revealed.Their association with growth traits was evaluated in 290 oysters from five families,and was further confirmed in another 186 oysters from three fast-growing strains.Seventeen and twelve SNPs were identified in the Ras gene andβ-glucosidase gene,respectively.Among these SNPs,four SNPs in each gene(Ras:C.86C>A,C.90T>C,C.112A>G and C.118G>A;β-glucosidase:C.247G>A,C.284C>T,C.1260C>T and C.1293T>C)were significantly(P<0.05)associated with the growth of these oysters.Furthermore,eight and nine haplotypes were constructed in the Ras gene andβ-glucosidase gene,respectively.Oysters with both haplotypes R-Hap5(CCAA)andβ-Hap7(ACCT),or with both R-Hap 6(ATGG)andβ-Hap 6(ACTC),or with both R-Hap 6 andβ-Hap 9(ACTT),or with both R-Hap 7(ATAA)andβ-Hap 7,showed the highest growth performances.These results provide candidate markers for selecting C.gigas with fast growth.
基金This work was supported by grants from the National Natural Science Foundation of China(No.31972789)the Earmarked Fund for Agriculture Seed Improvement Project of Shandong Province(No.2017LZGC009)+1 种基金the Science and Technology Development Project of Weihai City(No.2018NS01)the Ocean University of China-Auburn University Joint Research Center for Aquaculture and Environmental Science.
文摘Shell color is regarded as an economic trait in many breeding programs of bivalve mollusks,but the relationship between shell color and production traits remains controversial.In our breeding program of Crassostrea gigas,solid white,black,and orange shell lines were obtained,and second-generation(F2)and testcross families with segregating shell colors were constructed by crossing these three lines.These segregating families provided ideal samples for investigating the relationship between shell color and production traits in C.gigas.The growth and survival of 7-month-old oysters with different shell colors sampled within the same families were compared in seven F2 families and 13 testcrosses.In addition,the growth and survival of oysters from the three shell color lines were compared at 4 and 16 months of age.The growth and survival rates of the orange shell line were significantly lower than those of the white and black shell lines.However,no significant difference in growth between oysters with different shell colors was observed within segregating families,except the testcrosses produced by crossing orange-and white-shelled grandparents,and no significant difference in survival was observed in any family.Overall,no significant correlation was observed between shell color and production traits in C.gigas.These results suggest that shell color cannot be used as a marker to guide the selection of growth and survival traits.Thus shell color and production traits should be selected independently in oyster breeding programs.
基金Supported by the Science&Technology Innovation Project of Laoshan Laboratory (No. LSKJ202203001)the Center for Ocean Mega-Research of Science+2 种基金Chinese Academy of Sciences (No. COMS2019Q11)the GHfund B (No. 20210702)the Taishan Scholars Program
文摘Caspase-8,first classified as a pro-apoptotic caspase,is considered to have arisen from duplication with caspase-10 and involves multiple immune and inflammatory responses in mammals.However,few are known on the phylogeny and function of caspase-8 in molluscs,one of the largest phyla in marine invertebrates.In this study,we conducted phylogenetic and functional analysis on molluscan caspase-8-like genes.Results indicate that duplication occurred in molluscan caspase-8-like genes,resulting in at least two caspase-8 copies in some groups of bivalves.Additional studies in Pacific oyster Crassostrea gigas showed different spatio-temporal expression patterns and subcellular localizations of CgCaspase-8-1 and CgCaspase-8-2.While no interaction was observed between CgCaspase-8-2 and CgFADD,the adaptor molecule in apoptosis,yeast two-hybrid and co-immunoprecipitation assays suggested the interaction between CgCaspase-8-1 and CgFADD,indicating its pro-apoptotic function.In addition,CgCaspase-8-1 showed interaction with the CARD domain of CgRIG-I.Together with two NF-κB subunits(Cgp105 and CgRel),their transcripts were up-regulated in response to poly(I:C)stimuli,supporting the immune function of both pro-and anti-inflammation.The results provide insight into the evolution and functional diversification of Bivalvia caspase-8 genes.
基金supported by the National Natural Science Foundation of China(No.11701546).
文摘Synonymous codons have different frequencies of usage in many species.Based on the frequency of usage,the codons can be divided into two groups,rare codons and abundant codons.Rare codons are found to be enriched at the start regions of genes,and it is assumed that these codons can reduce elongation speed of genes.However,the rare codon usage in different genomic regions of mollusks and their relationship with selective pressure has not been systematically investigated.In this study,the patterns of rare codon usage are characterized at whole genome level,and their relationship with selective pressures is investigated in Crassostrea gigas.The rare codons are enriched at the start regions of genes with high and medium expression levels,and their proportion is higher than those in the genes with low expression level.The genes with longer coding sequences and more exon numbers have lower fraction of rare codons at start regions.Rare codons have lower level of nucleotide diversity and higher frequency of rare mutations at start regions.This work is the first comprehensive investigation of the relationships between rare codon usage and some intrinsic genetic factors in mollusca species.The results suggest that the selective pressures play an important role in shaping the rare codon usage in the C.gigas genome.
基金This research work was financially supported National Natural Science Foundation of China(No.82003910)Guangdong Basic and Applied Basic Research Foundation(2020A1515110550)+2 种基金Funding Key R&D Program of Shandong Province(2022SFGC0105)Exploration Innovation Team(2021GXRC062),Jinan Talent Project for Universities(202228088)Key innovation Project of Qilu University of Technology(Shandong Academy of Sciences)(2022JBZ01-06).
文摘There is an increasing interest in discovering new antibacterial agents derived from nature to enhance the treatment of various bacterial infections.Defensins and their derived peptide fragments exhibit significant antibacterial activity without any cytotoxic effects,making them attractive features for potential novel antibacterial therapeutics.Crassostrea gigas,a traditional seafood that has been used worldwide for centuries,has its shells applied in Chinese medicine as Ostreae concha.In this study,bioinformatics analysis was used to obtain a novel antibacterial peptide,CGD-1,derived from marine Chinese medicine Ostreae concha.The physicochemical characterization and circular dichroism analysis results demonstrated that CGD-1 assembled into anα-helical structure in a simulated membrane environment,and it displayed antibacterial action against Gram-negative bacteria.The minimal inhibitory concentrations against both Pseudomonas aeruginosa ATCC27853 and Escherichia coli ATCC25922 were 25μM.CGD-1 was able to efficiently permeate the cell membrane.Changes in bacterial cell morphology were evaluated using a field emission scanning electron microscope.The results suggested that CGD-1 exerted its antibacterial activity through permeabilizing and disrupting the bacterial cell membrane.Therefore,CGD-1 may have potential applications in fighting against pathogenic bacteria such as P.aeruginosa and E.coli.
基金Supported by the National Key R&D Program of China(No.2019YFD0900803)the National Natural Science Foundation of China(No.41876185)+2 种基金the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.2018SDKJ0502)the Youth Talent Program Supported by Laboratory for Marine Fisheries Science and Food Production Processes of Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.2018-MFS-T13)the Modern Agro-industry Technology Research System(No.CARS-49)。
文摘Integrated Multi-Trophic Aquaculture(IMTA)is an effective method for sustainable aquaculture as species from different trophic levels could reduce negative effects from fed species in the environment.A proper proportion of different trophic species in an IMTA system could improve the aquaculture production and environmental sustainability.At present,research on the proper proportions for farming species is scarce.We investigated the effects of IMTA modes of oyster(Crassostrea gigas)and kelp(Saccharina japonica)in different weight ratios on water quality and carbonate system in a closed enclosure experiment for three days in the Sanggou Bay in Shandong Province,China,in December 2017.Nine collocation modes in oyster:kelp weight ratio were tested showing as 24:3,24:2,24:1,16:3,16:2,16:1,8:3,8:2,and 8:1.The water parameters were determined at 17:00 on Day 1(D1),and 6:00 and 17:00 on Days 2(D2)and 3(D3).As two-way ANOVA showed,all increased parameters(dissolved oxygen(DO),pH,chl a,the carbonate system and pCO2)were significantly related to oyster-kelp modes,and interaction between modes and time were also significant(P<0.05).On the 3th day,the 8:3 mode was the highest in DO,pH,chl a,CO32-(P<0.05),and dissolved inorganic carbon(DIC),HCO3-,CO2,and pCO2 were the lowest(P<0.05).According to previous references and the results of this study,the appropriate oyster:kelp proportion at the beginning of winter is from 8:2 to 8:3.The results of this study may help government to optimize the aquaculture structure of Sanggou Bay.
