Hard clam(Meretrix meretrix)has a rich shell color variation among individuals from light yellow to bluish gray,brown red,and black,which may associating with melanin.Tyrosinase(Tyr)is a key rate-limiting enzyme for t...Hard clam(Meretrix meretrix)has a rich shell color variation among individuals from light yellow to bluish gray,brown red,and black,which may associating with melanin.Tyrosinase(Tyr)is a key rate-limiting enzyme for the biosynthesis of melanin,which affects the dark color of animal skin,hair,fur,scales and feathers.Here,we isolated and characterized the full-length cDNA sequence of M.meretrix tyrosinase gene(MmTyr)which encodes a protein with 689 amino acids.Sequence characteristics and phylogenetic analysis showed that there are a variety of Tyr genes in mollusks,which can be divided into different categories.The abundance of MmTyr transcript was detected in six tissues including mantle,adductor muscle,digestive gland,foot,gill and siphon of adult M.meretrix with qRT-PCR.The results showed a higher expression specifically in the mantle,digestive gland and siphon,which was consistent with the phenotypic color difference.In the embryos and larvae at different developmental stages,high expression was found in the trochophore larvae and juvenile clams.Among three M.meretrix strains with different shell colors,the expression level of MmTyr and total melanin content in the mantle edge both showed significant differences,suggesting that MmTyr is involved in the formation of shell color.The results obtained in this study will improve our understanding of molluscan tyrosinase gene function and molecular mechanism of shell color pattern determination.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
In order to improve production and breed new broods of bay scallop Argopecten irradians irradians, different-colored orange, purple and white lines were established by two mating methods of self-fertilization and mass...In order to improve production and breed new broods of bay scallop Argopecten irradians irradians, different-colored orange, purple and white lines were established by two mating methods of self-fertilization and mass spawning at a commercial scallop hatchery in spring, 2002. And then larval growth and survival of different lines was compared to test whether there is a relationship between shell color and growth and survival at early developmental stage. Both growth and survival have no significant differences among different experimental larvae of self-fertilization or mass spawning. Results are as following in the order of orange, purple and white shell stock. For the self-fertilization, growth rates of larvae were 6.174, 6.412, and 6.599 μm/d, respectively. Survival rates of larvae at Day 3 were 74.41%, 76.86%, and 82.05%; Day 6 were 49.14%, 65.63%, and 52.79%; and Day 9 were 25.06%, 20.80%, and 26.47%, respectively. For the mass spawning, the growth rates were 7.836, 7.941, and 7.878 μm/d, respectively. Survival rates at Day 3 were 93.05%, 91.95%, and 92.50%; Day 6 were 79.17%, 78.05%, and 82.50%; and Day 9 were 34.72%, 36.67%, and 38.33%, respectively. The absence of any relationship between shell color and growth and survival at the larval stage may be resulted from their common genetic basis.展开更多
The shell color of Pacific oyster(Crassostrea gigas) is a desirable trait; but the nutritional studies on C. gigas with different shell colors have not been conducted. Through successive selective breeding, five shell...The shell color of Pacific oyster(Crassostrea gigas) is a desirable trait; but the nutritional studies on C. gigas with different shell colors have not been conducted. Through successive selective breeding, five shell color strains of black(B), purple(P), orange(O), golden(G) and white(W) C. gigas have been developed. The aim of this study was to evaluate the chemical composition and nutritional value of five shell color strains and one commercial population with a common color. The biochemical composition including moisture, total protein, glycogen, ash, total fat, fatty acids(FA), amino acids and minerals was detected. The results indicated that the protein(50.76%–56.57%) was the major component. The content of glycogen showed a significant difference between orange shell and golden shell strains, as well as between commercial population and golden shell strain. In addition, all shell color strains contained a large amount of essential amino acids(12.20–14.15 g(100 g)^(-1)), of them leucine(2.81–3.29 g(100 g)^(-1)) and lysine(2.79–3.28 g(100 g)^(-1)) were predominant. The oysters were rich in polyunsaturated fatty acids(42.26%–45.24% of total fatty acid) with high levels of DHA(18.53%–21.16% of total fatty acid) and EPA(17.23%–18.68% of total fatty acid). Significant differences of mineral contents(Mg, Zn, Fe and Cu) were identified among the six populations. These results indicated that C. gigas with different shell colors presented rich nutritional value with high protein, glycogen, essential amino acids and polyunsaturated fatty acids. The biochemical composition obtained in this study is useful for selective breeding of C. gigas with different shell colors.展开更多
Molluscan shell color has received persistent attention for its distinctive diversity and complexity. In the present study, six transcriptome libraries obtained from two developmental stages, pre-pigmentation and post...Molluscan shell color has received persistent attention for its distinctive diversity and complexity. In the present study, six transcriptome libraries obtained from two developmental stages, pre-pigmentation and post-pigmentation, were used for paired-end sequencing in the bay scallop Argopecten irradians. In total, 289 839 646 paired-end reads were assembled into 70 929 transcripts. Using BLASTX and BLASTN, 30 896 unigenes were successfully annotated against the SWISS-PROT, NR, and KOG database. Gene ontology annotation and Kyoto Encyclopedia of Genes and Genomes classification identified numbers of unigenes involved in biomineralization and pigmentation. Digital gene expression analysis revealed that melanin, trace metal elements and porphyrins are potentially involved in shell coloration of A. irradians.展开更多
The molecular basis of color polymorphism in the shells of the pearl oyster Pinctada fucata is largely unknown. We developed a red-shelled family line and used suppression subtractive hybridization (SSH) to screen for...The molecular basis of color polymorphism in the shells of the pearl oyster Pinctada fucata is largely unknown. We developed a red-shelled family line and used suppression subtractive hybridization (SSH) to screen for differentially expressed genes in red- and non-red-shelled pearl oysters. We constructed forward and reverse cDNA subtractive libraries consisting of 2 506 and 797 clones, respectively. Among 343 randomly selected clones in the forward library, 304 sequences were identified in GenBank using BLASTx and BLASTn. Of the 304 sequences, 13 showed no similarity to known sequences and 291 were matched with known genes of the pearl oyster, including shematrin-1, shematrin-2, shematrin-6, shematrin-7, nacrein, nacrein-like protein, aspein for shell matrix protein, glycine-rich protein, mantle gene 5, 28S, EST00031, EST00036, 16S, and COΙ. In the reverse library, 7 clones were sequenced and analyzed by BLAST. Two sequences shared similarity with EST00036 from the P. fucata subtraction cDNA library, four with the P. fucata mitochondrial gene for 16S rRNA and 1 with P. fucata shematrin-2. We evaluated the expression of 12 genes from the forward library using RT PCR. Two sequences matched with 16S and COΙ so were considered to be false positives. The remaining 10 sequences were differentially expression in the red-shelled pearl oysters. Our results suggest that differential expression of these genes may be related to color variation in the red-shelled family line of the pearl oyster.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
基金supported financially by the National Key Research and Development Program of China (No. 2018YFD0901404)the National Natural Science Foundation of China (No. 31772846)+3 种基金the Zhejiang Provincial Natural Science Foundation (No. LY16C190004)the General project of Zhejiang Provincial Educational Department (No. Y201329410)the Open-End Funds of Jiangsu Key Laboratory of Marine Biotechnology (No. HS16001)the Modern Agro-Industry Technology Research System (No. CARS-49)
文摘Hard clam(Meretrix meretrix)has a rich shell color variation among individuals from light yellow to bluish gray,brown red,and black,which may associating with melanin.Tyrosinase(Tyr)is a key rate-limiting enzyme for the biosynthesis of melanin,which affects the dark color of animal skin,hair,fur,scales and feathers.Here,we isolated and characterized the full-length cDNA sequence of M.meretrix tyrosinase gene(MmTyr)which encodes a protein with 689 amino acids.Sequence characteristics and phylogenetic analysis showed that there are a variety of Tyr genes in mollusks,which can be divided into different categories.The abundance of MmTyr transcript was detected in six tissues including mantle,adductor muscle,digestive gland,foot,gill and siphon of adult M.meretrix with qRT-PCR.The results showed a higher expression specifically in the mantle,digestive gland and siphon,which was consistent with the phenotypic color difference.In the embryos and larvae at different developmental stages,high expression was found in the trochophore larvae and juvenile clams.Among three M.meretrix strains with different shell colors,the expression level of MmTyr and total melanin content in the mantle edge both showed significant differences,suggesting that MmTyr is involved in the formation of shell color.The results obtained in this study will improve our understanding of molluscan tyrosinase gene function and molecular mechanism of shell color pattern determination.
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This work was financially supported by Project of Scientific Innova-tion, Chinese Academy of Sciences (ZKCX2-211).
文摘In order to improve production and breed new broods of bay scallop Argopecten irradians irradians, different-colored orange, purple and white lines were established by two mating methods of self-fertilization and mass spawning at a commercial scallop hatchery in spring, 2002. And then larval growth and survival of different lines was compared to test whether there is a relationship between shell color and growth and survival at early developmental stage. Both growth and survival have no significant differences among different experimental larvae of self-fertilization or mass spawning. Results are as following in the order of orange, purple and white shell stock. For the self-fertilization, growth rates of larvae were 6.174, 6.412, and 6.599 μm/d, respectively. Survival rates of larvae at Day 3 were 74.41%, 76.86%, and 82.05%; Day 6 were 49.14%, 65.63%, and 52.79%; and Day 9 were 25.06%, 20.80%, and 26.47%, respectively. For the mass spawning, the growth rates were 7.836, 7.941, and 7.878 μm/d, respectively. Survival rates at Day 3 were 93.05%, 91.95%, and 92.50%; Day 6 were 79.17%, 78.05%, and 82.50%; and Day 9 were 34.72%, 36.67%, and 38.33%, respectively. The absence of any relationship between shell color and growth and survival at the larval stage may be resulted from their common genetic basis.
基金supported by the grants from the National Natural Science Foundation of China(No.31772843)the Key Research and Development Program of Shandong Province(No.2016ZDJS06A06)the Industrial Development Project of Qingdao City(17-3-3-64-nsh)
文摘The shell color of Pacific oyster(Crassostrea gigas) is a desirable trait; but the nutritional studies on C. gigas with different shell colors have not been conducted. Through successive selective breeding, five shell color strains of black(B), purple(P), orange(O), golden(G) and white(W) C. gigas have been developed. The aim of this study was to evaluate the chemical composition and nutritional value of five shell color strains and one commercial population with a common color. The biochemical composition including moisture, total protein, glycogen, ash, total fat, fatty acids(FA), amino acids and minerals was detected. The results indicated that the protein(50.76%–56.57%) was the major component. The content of glycogen showed a significant difference between orange shell and golden shell strains, as well as between commercial population and golden shell strain. In addition, all shell color strains contained a large amount of essential amino acids(12.20–14.15 g(100 g)^(-1)), of them leucine(2.81–3.29 g(100 g)^(-1)) and lysine(2.79–3.28 g(100 g)^(-1)) were predominant. The oysters were rich in polyunsaturated fatty acids(42.26%–45.24% of total fatty acid) with high levels of DHA(18.53%–21.16% of total fatty acid) and EPA(17.23%–18.68% of total fatty acid). Significant differences of mineral contents(Mg, Zn, Fe and Cu) were identified among the six populations. These results indicated that C. gigas with different shell colors presented rich nutritional value with high protein, glycogen, essential amino acids and polyunsaturated fatty acids. The biochemical composition obtained in this study is useful for selective breeding of C. gigas with different shell colors.
基金Supported by the China Agriculture Research System(No.CARS-49)the Science and Technology Service Network Initiative of Chinese Academy of Sciences
文摘Molluscan shell color has received persistent attention for its distinctive diversity and complexity. In the present study, six transcriptome libraries obtained from two developmental stages, pre-pigmentation and post-pigmentation, were used for paired-end sequencing in the bay scallop Argopecten irradians. In total, 289 839 646 paired-end reads were assembled into 70 929 transcripts. Using BLASTX and BLASTN, 30 896 unigenes were successfully annotated against the SWISS-PROT, NR, and KOG database. Gene ontology annotation and Kyoto Encyclopedia of Genes and Genomes classification identified numbers of unigenes involved in biomineralization and pigmentation. Digital gene expression analysis revealed that melanin, trace metal elements and porphyrins are potentially involved in shell coloration of A. irradians.
基金Supported by National High Technology Research and Development Program of China (863 Program) (No. 2006AA10A409)the Knowledge Innovation Program of the South China Sea Institute of Oceanology, Chinese Academy of Sciences (No. SQ200906)+2 种基金the Science and Technology Program of Guangdong Province (No. 2008A020100004)the National Key Technology Research and Development Program (No. 2007BAD29B01-8)the Key Plan for Marine Development of Guangdong Province (No. A200708C01)
文摘The molecular basis of color polymorphism in the shells of the pearl oyster Pinctada fucata is largely unknown. We developed a red-shelled family line and used suppression subtractive hybridization (SSH) to screen for differentially expressed genes in red- and non-red-shelled pearl oysters. We constructed forward and reverse cDNA subtractive libraries consisting of 2 506 and 797 clones, respectively. Among 343 randomly selected clones in the forward library, 304 sequences were identified in GenBank using BLASTx and BLASTn. Of the 304 sequences, 13 showed no similarity to known sequences and 291 were matched with known genes of the pearl oyster, including shematrin-1, shematrin-2, shematrin-6, shematrin-7, nacrein, nacrein-like protein, aspein for shell matrix protein, glycine-rich protein, mantle gene 5, 28S, EST00031, EST00036, 16S, and COΙ. In the reverse library, 7 clones were sequenced and analyzed by BLAST. Two sequences shared similarity with EST00036 from the P. fucata subtraction cDNA library, four with the P. fucata mitochondrial gene for 16S rRNA and 1 with P. fucata shematrin-2. We evaluated the expression of 12 genes from the forward library using RT PCR. Two sequences matched with 16S and COΙ so were considered to be false positives. The remaining 10 sequences were differentially expression in the red-shelled pearl oysters. Our results suggest that differential expression of these genes may be related to color variation in the red-shelled family line of the pearl oyster.
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.
