Food sources of the Manila clam Ruditapes philippinarum in intertidal areas: evidence from stable isotope analysis

Based on stable isotope analysis, we characterized the dietary regime of the Manila clam Ruditapes philippinarum inhabiting intertidal areas along the Liaodong Peninsula, Northern China. Samples, including particulate organic matter (POM; n =30), benthic microalgae (BMI; n =30) and R. philippinarum (n =60), were collected from six sampling sites displaying the same ecological conditions. Of the two primary food sources, POM was more depleted in δ ¹³C (?20.61‰ to ?22.89‰) than BMI was (?13.90‰ to ?16.66‰). With respect to ¹⁵N, BMI was more enriched (2.90‰ to 4.07‰) than POM was (4.13‰ to 5.12‰). The δ ¹³C values of R. philippinarum ranged from ?18.78‰ to ?19.35‰ and the δ ¹⁵N values from 7.96‰ to 8.63‰, which were intermediate between the POM and BMI values. In a two-source isotope mixing model, we estimated the relative contributions of POM and BMI to the diet of R. philippinarum to be 74.2% and 25.8%, respectively. We conclude that R. philippinarum feeds mainly on POM, and BMI is also an important supplemental food source in intertidal areas.     

菲律宾蛤仔肉不同提取物呈味特性

【目的】系统评价菲律宾蛤仔(Ruditapes philippinarum)肉不同提取物的呈味物质含量和呈味特征差异。【方法】以新鲜菲律宾蛤仔肉为原材料,采用水煮和酶解的不同提取方式,制得两种冻干粉,比较分析两者游离氨基酸、呈味核苷酸、有机酸、有机碱和无机离子含量的差异,通过滋味活性值(Taste Activity Value,TAV)评价其对滋味的贡献,并结合感官评价法和电子舌检测法考察其整体呈味特征。【结果】感官评定结果表明,水煮提取物鲜味和甜味强于酶解提取物;鲜味、甜味和苦味是酶解提取物的重要味觉特征;电子舌主成分分析结果亦表明水煮提取物更接近谷氨酸钠的呈鲜特性。水煮和酶解提取物中游离氨基酸、呈味核苷酸、有机酸、有机碱和无机离子的含量均存在显著差异(P<0.05)。不同的呈味物质由于含量的差异及呈味组分间的相互作用导致水煮和酶解提取物的整体滋味存在差异。【结论】菲律宾蛤仔的呈味特性与其水溶性呈味物质密切相关,酶解提取物虽增加了氨基酸等的总体含量,但对鲜味、甜味的贡献不大。     

菲律宾蛤仔糖胺聚糖的纯化及单糖组成的研究

菲律宾蛤仔中提取的糖胺聚糖(GAGs)粗品,经DEAE-52-离子交换柱层析和Sephadex G-100凝胶柱纯化后,采用Sephadex G-100凝胶柱层析法测定该糖胺聚糖纯品F-1-1的相对分子质量,并以薄板层析(TLC)法对F-1-1的酸水解液进行单糖组成分析。结果表明:两级纯化得到均一的糖胺聚糖,其相对分子质量为4.4×104,单糖组分主要为氨基半乳糖、半乳糖、葡萄糖;对多糖进行两级纯化效果较好,纯品可进行结构分析;TLC法可快速分析水解多糖的单糖组成。     

The influence of salinity on toxicological effects of arsenic in digestive gland of clam Ruditapes philippinarum using metabolomics

Ruditapes philippinarum,a clam that thrives in intertidal zones of various salinities,is a useful biomonitor to marine contaminants.We investigated the influence of dilution to 75% and 50% of normal seawater salinity(31.1) on the responses of the digestive gland of R.philippinarum to arsenic exposure(20 μg/L),using nuclear magnetic resonance(NMR)-based metabolomics.After acute arsenic exposure for 48 h,salinity-dependent differential metabolic responses were detected.In normal seawater,arsenic exposure increased the concentrations of branched-chain amino acids,and of threonine,proline,phosphocholine and adenosine,and it decreased the levels of alanine,hypotaurine,glucose,glycogen and ATP in the digestive glands.Differential changes in metabolic biomarkers observed at lower salinity(～23.3) included elevation of succinate,taurine and ATP,and depletion of branched-chain amino acids,threonine and glutamine.Unique effects of arsenic at the lowest salinity(～15.6) included down-regulation of glutamate,succinate and ADP,and up-regulation of phosphocholine.We conclude that salinity influences the metabolic responses of this clam to arsenic.     

Annual variations of biogenic element contents of manila clam (Ruditapes philippinarum) bottom-cultivated in Jiaozhou Bay,China

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.     

Genetic analysis of four populations of redlip mullet (Chelon haematocheilus) collected in China seas

Horizontal starch gel electrophoresis was used to investigate genetic structures of four populations (Dandong, Rizhao, Ningbo and Guangzhou) of redlip mullet (Chelon haematocheilus). Fourteen loci of ten enzymes (G3PDH, IDHP, LAP, LDH, MDH, MPI, PGDH, PGM, SDH, and SOD) were identified. The proportions of polymorphic loci varied from 0.07 to 0.14. The average observed and expected heterozygosities ranged from 0.02 to 0.05 and from 0.02 to 0.04 respectively among the 4 populations. The average number of efficient alleles of each locus varied from 1.02 to 1.06. The genetic distance among populations was from 0.0004 to 0.0021. The genetic distances between Dandong, Rizhao and Ningbo populations were small, while those between Guangzhou population and other three populations were relatively high. The result indicated the possible divergence of redlip mullet between the South China Sea and the other sea areas of China due to geographic isolation.     

有棘和无棘两种表型栉江珧同工酶差异的比较

采用垂直板聚丙烯酰胺凝胶电泳对有棘和无棘两种不同表型的栉江珧（Ａｔｒｉｎａ ｐｅｃｔｉｎｔａ）的外套膜组织进行了ＥＳＴ 和ＳＯＤ 同工酶比较研究。结果显示这两种类型的酶谱表达有一定差异,但同时也存在中间类型,表明有棘和无棘的表型差异,尚不能提供它们应划分为两个种的充足证据     

Isozyme Analysis of Spotted Halibut Verasper variegatus Temminck et Schlegel

To investigate the tissue-specificities of isozymes and the genetic structure of wild spotted halibut ( Verasper variegatus) population, horizontal starch gel electrophoresis was performed on 45 individuals collected in part of the Yellow Sea. The performances of 17 isozymes in 8 kinds of tissues or organs were screened preliminarily in a TC-7.0 buffer system. The results showed that the screened isozymes displayed remarkable tissue-specificities. Finally, 14 enzymes (AAT, ADH, EST, GPI, G3PDH, IDHP, LAP, LDH, MDH, MPI, PGDH, PGM, SDH and SOD) and 4 kinds of tissues (eye, skeleton muscle, liver and heart) were selected for genetic analysis. Fourteen isozymes are encoded by 20 loci, and 9 of them are poly-morphic. The polymorphic loci are AAT-1*, GPI-2*, G3PDH*, IDHP-1*, LDH*, MPI*, PGM-1*, PGM-2* and SDH*, and the proportion of polymorphic loci is 0.450 0 (P0.99). The mean values of observed and expected heterozygosities are 0.027 8 and 0.026 5, respectively and the average effective number of alleles is 1.067 5.     

Isozyme analysis of spotted halibut Verasper variegatus temminck et schlegel

To investigate the tissue-specificities of isozymes and the genetic structure of wild spotted halibut (Verasper variegates) population, horizontal starch gel electrophoresis was performed on 45 individuals collected in part of the Yellow Sea. The performances of 17 isozymes in 8 kinds of tissues or organs were screened preliminarily in a TC-7.0 buffer system. The results showed that the screened isozymes displayed remarkable tissue-specificities. Finally, 14 enzymes (AAT, ADH, EST, GPI, G3PDH, IDHP, LAP, LDH, MDH, MPI, PGDH, PGM, SDH and SOD) and 4 kinds of tissues (eye, skeleton muscle, liver and heart) were selected for genetic analysis. Fourteen isozymes are encoded by 20 loci, and 9 of them are polymorphic. The polymorphic loci are AAT-1*. GPI-2* G3PDH*, IDHP-1*, LDH*, MPI*, PGM-1*. PGM-2* and SDH*, and the proportion of polymorphic loci is 0.4500 (P0.99). The mean values of observed and expected heterozygosities are 0.027 8 and 0.026 5, respectively and the average effective number of alleles is 1.067 5.     

Isozyme expression of Chinese and Japanese populations of Chlamys farreri and their reciprocal hybrids

Chinese and Japanese population of Chlamys farreri and their reciprocal hybrids were surveyed in isozyme variability at 13 loci by polyacrytamide gel electrophoresis (PAGE). Isozyme banding patterns indicated these hybrids were diploid. Loci that were observed as being monomorphic in inbred populations of C. farreri were also found to be monomorphic in filial progeny; loci that observed to be polymorphic in parental type generations were also polymorphic in hybrid generations. Differences existed among allelic frequency of the four types of cross. Within the reciprocal hybrids the expression of malic enzyme (ME) isozyme was sufficient to distinguishing individual hybrids because of the band, Rf=0.38. However, there were no noticeable variations among all the samples to differentiate one from another. Inbreeding was likely to be the main problem in aquaculture. The introduction of new broodstock can improve the genetic diversity. Hybrid vigor has manifested to a certain extent in the present study.     

Isozyme expression of Chinese and Japanese populations of Chlamys farreri and their reciprocal hybrids

Chinese and Japanese population ofChlamys farreri and their reciprocal hybrids were surveyed in isozyme variability at 13 loci by polyacrytamide gel electrophoresis (PAGE). Isozyme banding patterns indicated these hybrids were diploid. Loci that were observed as being monomorphic in inbred populations ofC. farreri were also found to be monomorphic in filial progeny; loci that observed to be polymorphic in parental type generations were also polymorphic in hybrid generations. Differences existed among allelic frequency of the four types of cross. Within the reciprocal hybrids the expression of malic enzyme (ME) isozyme was sufficient to distinguishing individual hybrids because of the band, Rf=0.38. However, there were no noticeable variations among all the samples to differentiate one from another. Inbreeding was likely to be the main problem in aquaculture. The introduction of new broodstock can improve the genetic diversity. Hybrid vigor has manifested to a certain extent in the present study. Supported by the National “973” Program (G1999012008) and “863” Program (2002AA626020).     

Research on heavy metals in Ruditapes philippinarum and soda industry wastes

Heavy metals pollution in Jiaozhou Bay was studied in Ruditapes. philippinarum, a bioindicator of seawater pollution. Heavy metals in soda industry wastes “white mud” were also studied. Comparison of microwave digestion method with general digestion method revealed that microwave digestion is superior to general digestion in precision, recovery, digestion speed and efficiency, etc. Cd concentration in Hongdao R.philippinarum samples exceeded the national standard by 0.046 mg/kg, that of Yinghai sample by 0.02 mg/kg,and that of Hongshiya sample by 0.22 mg/kg. Sample Pb concentration in Hongshiya was found to exceed the national standard by 0.02 mg/kg. However the heavy metals concentration in R. philippinarum near the Qingdao Alkaline Factory was complied with the standard. This was proved by Penaeus chinensis culture experiment.Therefore, the possible contamination source may come from other land areas.     

Genetic Analysis of Four Populations of Redlip Mullet(Chelon haematocheilus) Collected in China Seas

1 Introduction The redlip mullet, (Chelon haematocheilus) (Tem-minck et Schlegel, 1845), belongs to the family Mugili-dae. It is mainly distributed in the coastal areas of Korea, Japan and China (Wang et al., 2000). Because of the good adaptation to envir…     

Manila clam Venerupis philippinarum as a biomonitor to metal pollution

The Manila clam Venerupis philippinarum is a good biomonitor/bioindicator to marine metal pollution and is frequently used in aquatic toxicology. Two dominant pedigrees (white and zebra) of clam are distributed in the Bohai Sea; however, little attention has been paid to potential biological differences between these two pedigrees. In this study, we tested the sensitivity of both pedigrees to marine metal (cadmium and zinc) pollution biomonitoring and marine environmental toxicology. Results demonstrate significant biological differences in gills of white and zebra clams based on metabolic profiles and antioxidant enzyme activities. In addition, we found that hypotaurine, malonate and homarine were relatively high in white clam gills, while alanine, arginine, glutamate, succinate, 4-aminobutyrate, taurine and betaine were high in zebra clam gills. Zebra clam gills were also more sensitive to a mixture of Cd and Zn, as shown by antioxidant enzyme activities and metabolic profiles, but white clam gills could accumulate more Zn. Therefore, we suggest that the white pedigree can be used as a biomonitor to marine Zn pollution, whereas the zebra pedigree can be used for toxicology studies on Cd and Zn mixed pollution.     

Larval and juvenile growth performance of Manila clam hybrids of two full-sib families

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.     

花胚胎发育及仔鱼阶段同工酶的初步分析

<正>鱼类胚胎发育是一个复杂而有序的系统工程,是基因时空综合表达结果。已有的研究证明:机体在生长发育过程中会发生一系列复杂的同工酶时空表达变化,它是基因特异性表达的一种主要作用形式。同工酶研究是研究鱼类个体发育的有力手段之一,     

管角螺不同组织同工酶的研究

采用聚丙烯酰胺垂直板梯度凝胶电泳技术，对管角螺7种组织（外套膜、肌肉、肝脏、心脏、生殖腺和缠卵腺）的5种同工酶（EST、SOD、ME、MDH、LDH）进行了分析，结果表明：5种同工酶存在不同程度的组织特异性，SOD、EST、LDH在肝脏组织中有较高活性，而MDH、ME在心脏组织中活性较高。     

A Comparative Study of Genetic Variation betwccn Chinese Mitten Crab Eriocheir Sinensis and Hepu Mitten Crab E. Hepuensis

Horizontal starch gel electrophoresis was used to investigate the biochemical genetic structure of Chinese mittencrab Eriocheir sinensis and Hepu mitten crab E. hepuensis. Sixteen putative enzyme-coding loci were examined for forty-nineChinese mitten crabs and thirty-eight Hepu mitten crabs. Nine loci, AAT-1 *, AAT-2 *, G3PDH*, GPI*, IDHP-1 *, IDHP-2 *,MDH-1 *, MDH-2 * and PGM * , are polymorphic in Chinese mitten crab, and seven, AAT-1 *, AAT-2 *, GPI *, IDHP-1 *,MDH-1 *, MDH-2 * and PGM * , are polymorphic in Hepu mitten crab. The proportion of polymorphic loci and the expectedheterozygosity are 0.562 5 and 0.080 3 for Chinese mitten crab, and 0.437 5 and 0.075 4 for Hepu mitten crab. The Nei' s ge-netic distance between two species is 0.002 4.     

管角螺不同组织同工酶的研究

采用聚丙烯酰胺垂直板梯度凝胶电泳技术,对管角螺7种组织(外套膜、肌肉、肝脏、心脏、生殖腺和缠卵腺)的5种同工酶(EST、SOD、ME、MDH、LDH)进行了分析,结果表明:5种同工酶存在不同程度的组织特异性,SOD、EST、LDH在肝脏组织中有较高活性,而MDH、ME在心脏组织中活性较高。     

Observations on shell growth and morphology of the bivalve Ruditapes philippinarum

The bivalve Ruditapes philippinarum is not only one of the main mollusc species in the west Pacific Ocean, but also one of the main species for aquaculture in China. Knowledge of growth of the R. philippinarum shell will improve our understanding of the shell as an environmental archive. It is also useful for the aquaculture of R. philippinarum. In this research, a hanging box culture method was introduced in the culture of R. philippinarum. The bivalves were cultured for 126 days, from March 31 to August 3, 2002. The average growth rates of shell width, height, and thickness were 0.069, 0.046, and 0.032 mm/d, respectively. The mean increase of average individual wet mass was 0.028 g/d. The largest growth rates of both shell and average individual wet mass occurred in June, indicating that water temperature and bivalve reproduction were 2 important factors. The shell morphology underwent significant changes with shell growth. The ratio of height to thickness (value of B/C) shifted 1.58 in the first 60 days to 1.54 in the last 30 days, which was resulted from the change in major shell growth direction. Periodic changes in the B/C ratio led to corrugated shell form, which could be used to determine the age of the shell.