Although the impact of ocean acidification on marine bivalves has been previously investigated under mainly controlled laboratory conditions,it is still unclear whether the impact of acidification on sediment-burrowin...Although the impact of ocean acidification on marine bivalves has been previously investigated under mainly controlled laboratory conditions,it is still unclear whether the impact of acidification on sediment-burrowing species differs between those within or without sediment.In order to fill this gap in our knowledge,we compared shell properties of the infaunal Manila clam(Ruditapes philippinarum)exposed to three pH concentrations(7.4,7.7,and 8.0),within and without sediments.In the first experiment(140 d),clams were exposed to seawater in an acidification system without sediment.A decrease in shell weight corresponding to the increase in dissolution rate was observed in the group ofpH 7.4,at which shell color disappeared or whitened.SEM observations confirmed the changes of the external shell surface.In the second experiment(170 d),sediment was placed at the bottom of each exposure chamber.The effects were found obvious in shell dissolution rate and shell color in the shell specimens exposed to overlying seawater but not found in the shell specimens exposed to sediment.Although the experimental period was longer in the second experiment,shell specimens in the first experiment were more seriously damaged than those in the second experiment under acidic seawater conditions.Our results,in relation to the defense function of the shell,show that marine bivalves in burrowing behavior are more adaptable to seawater acidification than those who do not burrow into sediment.展开更多
Manila clam(Ruditapes philippinarum) was monthly sampled from its benthic aquaculture area in Jiaozhou Bay from May 2009 to June 2010. The annual variations of major elemental composition, organic content, fatness and...Manila clam(Ruditapes philippinarum) was monthly sampled from its benthic aquaculture area in Jiaozhou Bay from May 2009 to June 2010. The annual variations of major elemental composition, organic content, fatness and element ratio of Manila clam were examined. The element removal effect of clam farming in Jiaozhou Bay was analyzed based on natural mortality and clam harvest. The results indicated that the variation trend of carbon content in shell(Cshell) was similar to that in clam(Cclam). Such a variation was higher in summer and autumn than in other seasons, which ranged from 9.10 ± 0.13 to 10.38 ± 0.09 mmol g-1 and from 11.28 ± 0.29 to 12.36 ± 0.06 mmol g-1, respectively. Carbon content of flesh(Cflesh) showed an opposite variation trend to that of shell in most months, varying from 29.42 ± 0.05 to 33.64 ± 0.62 mmol g-1. Nitrogen content of shell(Nshell) and flesh(Nflesh) changed seasonally, which was relatively low in spring and summer. Nshell and Nflesh varied from 0.07 ± 0.009 to 0.14 ± 0.009 mmol g-1 and from 5.46 ± 0.12 to 7.39 ± 0.43 mmol g-1, respectively. Total nitrogen content of clam ranged from 0.50 ± 0.003 to 0.76 ± 0.10 mmol g-1 with a falling tend except for a high value in March 2010. Phosphorus content of clam(Nclam) fluctuated largely, while phosphorus content of shell(Pshell) was less varied than that of flesh(Pflesh). Pshell varied from 0.006 ± 0.001 to 0.016 ± 0.001 mmol g-1; while Pflesh fluctuated between 0.058 ± 0.017 and 0.293 ± 0.029 mmol g-1. Pclam ranged from 0.015 ± 0.002 to 0.041 ± 0.006 mmol g-1. Carbon and nitrogen content were slightly affected by shell length, width or height. Elemental contents were closely related to the reproduction cycle. The removal amounts of carbon, nitrogen and phosphorus from clam harvest and natural death in Jiaozhou Bay were 2.92×104 t, 1420 t and 145 t, respectively. The nutrient removal may aid to reduce the concentrations of nitrogen and phosphorus, the main causes of eutrophication, and to maintain the ecosystem health of Jiaozhou Bay.展开更多
In order to determine whether growth performance could be improved by hybridizing full-sib families of Manila clam(Ruditapes philippinarum), crosses between two full-sib families including self and reciprocal crosses ...In order to determine whether growth performance could be improved by hybridizing full-sib families of Manila clam(Ruditapes philippinarum), crosses between two full-sib families including self and reciprocal crosses were carried out. The effects of heterosis, combining ability and interaction on the growth of shell length were estimated. The results showed that the growth of hybrid larvae was intermediate between parents on days 6 and 9. Heterosis on shell length was observed, which varied at juvenile stage. The cross of ♂A×♀B(Hp varied between 10.41% and 68.27%) displayed larger heterosis than ♂B×♀A(Hp varied between 1.89% and 32.33%) did, suggesting that ♂A×♀B was an ideal hatchery method of improving the growth performance of Manila clam. The variances of general combining ability(GCA), special combining ability(SCA) and interaction(I) were significant in shell length(P < 0.05), indicating that both additive and non-additive genetic factors were important contributors to the growth of larvae and juveniles. The GCA for shell length of ♂A×♀B was higher than that of ♂B×♀A at both larval and juvenile stages. This confirmed that the cross between ♂A and ♀B showed great growth in shell length. In summary, the growth of Manila clam seeds could be improved by hybridizing selected parents from large numbers of full-sib families.展开更多
Objective:To investigate molecular characterization and the immune responses of Manila clam hydramacin(Rp-hdmc).Methods:cDNA sequence of hydramacin was isolated from Manila clam transcriptome database.Molecular charac...Objective:To investigate molecular characterization and the immune responses of Manila clam hydramacin(Rp-hdmc).Methods:cDNA sequence of hydramacin was isolated from Manila clam transcriptome database.Molecular characterization of hydramacin cDNA was performed by BLAST and SWISS-MODEL bioinformatics programs.Tissue-specific expression and transcriptional regulation after Vibrio tapetis challenge was done by quantitative real time PCR.Results:Rp-hdmc has 291 bp open reading frame(ORF),encoding 97 amino acids with a mature hydramacin consisting of 77 amino acid residues.In un-challenged clam,Rp-hdmc was constitutively expressed in all tested tissues and the highest expression level was detected in gill.After pathogenic bacteria Vibrio tapetis challenge,Rp-hdmc mRNA was up-regulated in gill and hemocytes.Conclusions:We identified hydramacin cDNA(Rp-hdmc)from mollusk Manila clam that shows the characteristic features of hydramacin sequence.It has eight cysteine residues with four disulfide linkages,three helices and two β-strands in secondary structure.Expression results after V.tapetis challenges suggest that Rp-hdmc is involved in immune response against pathogenic bacteria.展开更多
基金Supported by the earmarked fund for Modern Agro-industry Technology Research System(No.CARS-48)
文摘Although the impact of ocean acidification on marine bivalves has been previously investigated under mainly controlled laboratory conditions,it is still unclear whether the impact of acidification on sediment-burrowing species differs between those within or without sediment.In order to fill this gap in our knowledge,we compared shell properties of the infaunal Manila clam(Ruditapes philippinarum)exposed to three pH concentrations(7.4,7.7,and 8.0),within and without sediments.In the first experiment(140 d),clams were exposed to seawater in an acidification system without sediment.A decrease in shell weight corresponding to the increase in dissolution rate was observed in the group ofpH 7.4,at which shell color disappeared or whitened.SEM observations confirmed the changes of the external shell surface.In the second experiment(170 d),sediment was placed at the bottom of each exposure chamber.The effects were found obvious in shell dissolution rate and shell color in the shell specimens exposed to overlying seawater but not found in the shell specimens exposed to sediment.Although the experimental period was longer in the second experiment,shell specimens in the first experiment were more seriously damaged than those in the second experiment under acidic seawater conditions.Our results,in relation to the defense function of the shell,show that marine bivalves in burrowing behavior are more adaptable to seawater acidification than those who do not burrow into sediment.
基金funded by the Public Science and Technology Research Funds Projects of Ocean (Grant No.200805066)National Natural Science Foundation of China (Grant No.41006083)Shandong Provincial Natural Science Foundation, China (Grant No.ZR2010DQ026)
文摘Manila clam(Ruditapes philippinarum) was monthly sampled from its benthic aquaculture area in Jiaozhou Bay from May 2009 to June 2010. The annual variations of major elemental composition, organic content, fatness and element ratio of Manila clam were examined. The element removal effect of clam farming in Jiaozhou Bay was analyzed based on natural mortality and clam harvest. The results indicated that the variation trend of carbon content in shell(Cshell) was similar to that in clam(Cclam). Such a variation was higher in summer and autumn than in other seasons, which ranged from 9.10 ± 0.13 to 10.38 ± 0.09 mmol g-1 and from 11.28 ± 0.29 to 12.36 ± 0.06 mmol g-1, respectively. Carbon content of flesh(Cflesh) showed an opposite variation trend to that of shell in most months, varying from 29.42 ± 0.05 to 33.64 ± 0.62 mmol g-1. Nitrogen content of shell(Nshell) and flesh(Nflesh) changed seasonally, which was relatively low in spring and summer. Nshell and Nflesh varied from 0.07 ± 0.009 to 0.14 ± 0.009 mmol g-1 and from 5.46 ± 0.12 to 7.39 ± 0.43 mmol g-1, respectively. Total nitrogen content of clam ranged from 0.50 ± 0.003 to 0.76 ± 0.10 mmol g-1 with a falling tend except for a high value in March 2010. Phosphorus content of clam(Nclam) fluctuated largely, while phosphorus content of shell(Pshell) was less varied than that of flesh(Pflesh). Pshell varied from 0.006 ± 0.001 to 0.016 ± 0.001 mmol g-1; while Pflesh fluctuated between 0.058 ± 0.017 and 0.293 ± 0.029 mmol g-1. Pclam ranged from 0.015 ± 0.002 to 0.041 ± 0.006 mmol g-1. Carbon and nitrogen content were slightly affected by shell length, width or height. Elemental contents were closely related to the reproduction cycle. The removal amounts of carbon, nitrogen and phosphorus from clam harvest and natural death in Jiaozhou Bay were 2.92×104 t, 1420 t and 145 t, respectively. The nutrient removal may aid to reduce the concentrations of nitrogen and phosphorus, the main causes of eutrophication, and to maintain the ecosystem health of Jiaozhou Bay.
基金supported by the earmarked fund for Modern Agro-industry Technology Research System (CARS-48)grants from the ‘863’ Project of China (2012AA10AA400)
文摘In order to determine whether growth performance could be improved by hybridizing full-sib families of Manila clam(Ruditapes philippinarum), crosses between two full-sib families including self and reciprocal crosses were carried out. The effects of heterosis, combining ability and interaction on the growth of shell length were estimated. The results showed that the growth of hybrid larvae was intermediate between parents on days 6 and 9. Heterosis on shell length was observed, which varied at juvenile stage. The cross of ♂A×♀B(Hp varied between 10.41% and 68.27%) displayed larger heterosis than ♂B×♀A(Hp varied between 1.89% and 32.33%) did, suggesting that ♂A×♀B was an ideal hatchery method of improving the growth performance of Manila clam. The variances of general combining ability(GCA), special combining ability(SCA) and interaction(I) were significant in shell length(P < 0.05), indicating that both additive and non-additive genetic factors were important contributors to the growth of larvae and juveniles. The GCA for shell length of ♂A×♀B was higher than that of ♂B×♀A at both larval and juvenile stages. This confirmed that the cross between ♂A and ♀B showed great growth in shell length. In summary, the growth of Manila clam seeds could be improved by hybridizing selected parents from large numbers of full-sib families.
基金Supported by the National Research Foundation(NRF)program of Ministry of Education,Science and Technology,Republic of Korea under research grant title of the Studies on the Manila clam(Ruditapes philippinarum)internal defense system(NRF-2011-0022671).
文摘Objective:To investigate molecular characterization and the immune responses of Manila clam hydramacin(Rp-hdmc).Methods:cDNA sequence of hydramacin was isolated from Manila clam transcriptome database.Molecular characterization of hydramacin cDNA was performed by BLAST and SWISS-MODEL bioinformatics programs.Tissue-specific expression and transcriptional regulation after Vibrio tapetis challenge was done by quantitative real time PCR.Results:Rp-hdmc has 291 bp open reading frame(ORF),encoding 97 amino acids with a mature hydramacin consisting of 77 amino acid residues.In un-challenged clam,Rp-hdmc was constitutively expressed in all tested tissues and the highest expression level was detected in gill.After pathogenic bacteria Vibrio tapetis challenge,Rp-hdmc mRNA was up-regulated in gill and hemocytes.Conclusions:We identified hydramacin cDNA(Rp-hdmc)from mollusk Manila clam that shows the characteristic features of hydramacin sequence.It has eight cysteine residues with four disulfide linkages,three helices and two β-strands in secondary structure.Expression results after V.tapetis challenges suggest that Rp-hdmc is involved in immune response against pathogenic bacteria.
