Abstract:The artificiallyinduced spawning and fertilization experiment of the razor clam(Sinonovaula constricta)was carried out at Ningbo Yongsheng Aquatic Seed Corporation Limited in October 2010.More than 1 000 fertilized eggs and early embryos of all developmental stages were collected and more than 100 were carefully observed to investigate a series of cytological events,including sperm penetration,maturation division,formation and chromosome association of the female and male pronuclei,early cleavage and polyspermy.Three techniques,including light microscopy,fluorescence microscopy by Hoechst 33 258 staining,paraffin section and hematoxylin-eosin staining,were used in the experiment to clarify the mechanisms of fertilization and embryonic development,which provided an important reference for research into its artificial reproduction and chromosome engineering breeding.The results of cytological observation indicated that most of unfertilized mature eggs ofS.constrictawere globular or oval(82-88 μm in diameter)and a few were pearshaped and the nuclear phase of them remained at the metaphase of the first maturation division.The sperms were the type of flagellum(55-58 μm in total length),with the bowlingshaped head and particularly slender acrosome rod like filament of flower.At water temperature 21-22 ℃ and salinity 10,after mix of sperms and eggs,sperms quickly attached to the surface of the eggs and activated the process of egg development.From 4 min to 6 min after insemination,sperm has penetrated into cytoplasm of egg and significantly expanded,while the shape of eggs become more round and the number of sperms outside the egg was significantly reduced.The fertilized eggs released PB1 at 12-15 min and PB2 at 20-25 min in the process of maturation division.After completion of the second maturation division,the sperm nucleus and the female nucleus expanded immediately,nuclear membrane reconstructed and developed into the male and female pronuclei 30 min after fertilization.Expansion of the sperm nucleus was earlier than that of the female nucleus.At formation of the female and male pronuclei,they approached gradually and all moved to the center of egg.At that time,the spermaster beside the male pronucleus was visible obviously.And then,the two pronuclei matched into an association nucleus after their chromosomes formed respectively.Subsequently,the chromosomes of association nucleus arranged on the metaphase plate of first mitosis.About 40 min,fertilized eggs carried out the first cleavage and the chromosomes were separated equally into two daughter cells which are different evidently in size.45-50 min after fertilization,embryos underwent the second cleavage which was fundamentally similar to the first cleavage,but the cleavage direction was almost vertical to the first cleavage furrow,and ultimately formed four daughter cells,three small and one big.60-70 min,embryos completed the third cleavage.Though the cleavage is also unequal division,embryos began spiral cleavage from the third cleavage.Additionally,the abnormal phenomena,such as polysperm and polyspindles,in the experiment were analyzed and the mechanisms of polyspermy prevention in marine mollusks were discussed and studied.

Abstract:In this paper,the optimum temperature,salinity and pH for juvenile growth of Ruditapes philippinarum were determined through the response surface methodology(RSM).The multivariate non-linear model was applied to study the interactions and optimization of the growth parameters for R.philippinarum which were explored by experiments.The results showed that:(1)there were significantly positive correlations between growth of shell-length and temperature and salinity within the range of experiment design.The relationship between growth of shell length and temperature and salinity and the growth of shelllength verged to positive correlation,and the calm grew better between pH 8 and 9;(2)there were no significant interactions between temperature,salinity and pH for the growth of juveniles.The multivariate nonlinear model is as follows:Y=4.08+0.10A+0.18B+0.11C-0.055A²-0.13B²-0.12C²(R²=0.977 4),the optimum conditions for germination are as follows:temperature 29.65 ℃ and salinity 23.35‰ and pH=8.46±0.09.The experimental results indicated that the proposed model is reasonably accurate and can be used for describing and predicting the growth features ofR.philippinarum in different environmental factors.

Abstract:Genetic parameters were estimated for growth and pond survival of channel catfish Ictalures punctatus using fullsib and halfsib families from cultured brood females collected from five different populations of the United States.The fry and juvenile were reared,tagged,and thereafter communalreared in one pond.Variance components and genetic parameters for growth and survival were estimated using a two traits animal model and a siredam threshold model.The estimated breeding values of all animals were calculated using best linear unbiased prediction.The heritability estimates for harvest body weight and harvest body length in the base population were high(0.41±0.074 and 0.32±0.064,respectively)and were significantly different from zero(P<0.05).These estimates are likely biased upwards due to the common environmental effect other than additive genetic effect,although tagging body weight and tagging body length was fitted as a covariate in the mixed model to remove this effect.There was a high phenotypic and genetic correlation between harvest body weight and harvest body length(0.93 and 0.97,respectively).Heritability of pond survival was low(0.037±0.016)but still significantly different from zero(P<0.05).The correlation between family breeding values for growth(harvest body weight and harvest body length)and pond survival were low(0.065 and 0.10,respectively)and not significantly different from zero(P>0.05).Therefore,growth and survival must be included as breeding objective and simultaneously selected in the future generations by using a multiple trait selection index method.

Abstract:Two experiments were designed to evaluate the pearl production traits of the third generation red(RS₃),yellow(YS₃),white(WS₃)and black(BS₃)shell colored lines.Different colored lines were used as host and donor oysters respectively.The pearl in Experiment Ⅰ,16 combinations were established by sampling the RS₃,YS₃,WS₃ and BS₃lines as honor and donor oysters.Another combination was established by using the common cultured stock and YS₃ as honor and donor oysters,respectively.And a total of seventeen combinations were established.The pearls were harvested after the honor oysters were cultured for twentyfour months.In Experiment Ⅱ,sixteen combinations were established by sampling the RS3,YS3,WS3 and BS3 lines as honor and donor oysters.The pearls were harvested after the honor oysters were cultured for eighteen months.After harvesting pearls,shell height growth and survival of the RS₃,YS₃,WS₃ and BS₃ lines were compared in both experiments.Retention rate,commercial pearl rate,better quality pearl rate and pearl thickness of each combination in Experiment Ⅰ and Ⅱ were compared.The results showed that there existed significant differences in mean shell height and survival among the RS₃,YS₃,WS₃ and BS₃ lines in Experiment Ⅰ and Ⅱ(P<0.05).The BS₃ line had the largest mean shell height compared with the RS₃,YS₃ and WS₃lines in Experiment Ⅰ and Ⅱ.The YS₃ line had the largest survival in Experiment Ⅰ and the BS₃ line had the largest survival in Experiment Ⅱ.In Experiment Ⅰ,there were significant differences in retention rate,commercial rate,perfect quality pearl rate and pearl performance values among the 17 combinations(P<0.05);There were insignificant differences in pearl thickness among the 17 combinations(P>0.05); The BW combination had the highest retention rate,commercial pearl rate,pearl thickness and pearl performance value,and the RB had the highest perfect quality pearl rate.In Experiment Ⅱ,there were significant differences in retention rate,commercial rate,pearl thickness,perfect quality pearl rate and pearl performance values among the 16 combinations(P<0.05).A combined analysis on host or donor oysters showed that the BS₃ line is desirable for host oyster to produce better quality pearl and is promising in the commercial pearl production.

Abstract:The large yellow croaker Larimichthys crocea is one of the most important fish species in Chinese mariculture,and the research about correlation analysis between growth-related traits and microsatellite markers is very rare.In this study,the genotype distribution of twenty-two microsatellite markers was investigated in an F₁ family of large yellow croaker Larimichthys crocea of 20-month old,and the correlation between growth-related traits and microsatellite markers was also analyzed using statistical method.The results are as follows:A total of 60 alleles were detected,and the average number of alleles and effective number of alleles were 2.73 and 2.37,respectively.The average observed heterozygosity(H_o)and expected heterozygosity(H_e)were 0.75 and 0.73,respectively.The genotype distribution of partly loci deviated severely from Mendel’s Laws,which suggested these loci might link with the adaptive gene,and LYC0446 may link with recessive homozygous lethal genes.We discovered that LYC0077 had significant impact on body weight,body length and body height(P<0.05),and the allele A(165 bp)had highest phenotype value and can be used as a molecular marker in selection breeding; LYC0015 and LYC0243 had significant impact on body height(P<0.05),and no significant effect on body length and body weight,and the allele C(110 bp)for LYC0015 and the allele A(160bp)for LYC0243 have positive effect on growth-related traits.Three genotypes of these loci with favorable effect on growthrelated traits were also determined,BC for LYC0015,AA for LYC0077 and AB for LYC0243 respectively.The best genotype combinations(BC/AA/AB)for LYC0015,LYC0077 and LYC0243 were also selected according to body weight,which conformed to the Additive Effects Model.The results presented here provide a starting point for the eventual mapping of economically important genes and markerassistant selection(MAS)in large yellow croaker.

Abstract:An acute salinity stress trial was conducted to estimate the effect of dietary magnesium level on serum osmolality,serum ions and ATP enzyme in gill filaments of Japanese seabass Lateolabrax japonicus.Four semipurified diets were formulated containing 0.413 g(D1),1.042 g(D2),1.577 g(D3),1.991 g(D4)magnesium(as magnesium sulphate)per kilogram diet to feed triplicate groups of fish［initial average weight(30±0.5)g］in freshwater circulation system for 50 days.Then all fish were transferred from freshwater to seawater to collect the serum and gill filaments at 0,1,3,6,12,24 h,respectively.The results showed that dietary magnesium levels significantly affected the levels of serum ions(Na+,Cl-,K+,Mg2+),serum osmolality and the activities of Na+/K+ATPase(NKA)and Ca2+/Mg2+ATPase(CMA)in gill filaments at 0 h(P<0.05).The serum osmolality,serum Mg2+and NKA of gill filaments increased with the increase of dietary magnesium levels.The levels of serum Mg2+ and osmolality,NKA and CMA activities in gill filaments of fish fed D4 were significantly higher than those fed the other diets(P<0.05),which indicated the Japanese seabass fed D4 was in a state of high intensity osmotic pressure regulating.During the salinity stress periods,the contents of serum Na+ and Cl-increased with the time extension of salinity stress,while the levels of serum osmolality,K+,Ca2+ and Mg2+,NKA and CMA activities fluctuated with stress duration from 0 to 24 h.NKA and CMA activities of fish fed D1 were significantly lower than those of other groups,which indicated it would reduce the sensitivities of NKA and MKA in gill filaments to salinity stimulation for Japanese seabass fed low magnesium level diet for 50 d.The results suggested that in order to reduce energy consumption for higher activities of NKA and CMA in gill,dietary magnesium level should be lower than 1.991 g/kg for Japanese seabass cultured in freshwater,however,high dietary magnesium levels improve NKA and CMA activities in gill,which could be beneficial to quick adaptation high salinity environment for Japanese seabass transferred from low salinity water into high salinity water.

Abstract:Studies were conducted to reveal the changes in sex ratio of juvenile halfsmooth tongue sole(Cynoglossus semilaevis)in cultured group by identified genetic sex and phenotypic sex with SSR marker and histological section,respectively.Meanwhile,further comparative analysis of growth and morphological characteristics among female,male,and sex reversal male(neo-male)were carried out.The results were as follows.Genetically,there was no significant difference between females and males with the sex ratio 45.5% to 54.5%; however,only 53.5% of genetic females had ovaries,while 46.5% of them had testes.The genetic males all had testes,no sex reversal happened.As a whole,the ratio of males was 75.2% and significantly higher than the ratio of females 24.8% morphologically(P<0.05).The growth of neomale halfsmooth tongue sole was higher than the normal males,while lower than the phenotypic females between 6 months post hatching(mph)to 8 mph,but no significant difference was found(P>0.05).Interestingly,the body height of the phenotypic females was higher than the phenotypic males when they had the same total length.In general,the average ratio of total length to body height of phenotypic males was 4.05,however,the phenotypic females was 3.89.This ratio would be useful for discrimination of the gender of juvenile halfsmooth tongue sole.

Abstract:The aim of this study was to investigate the effects of starvation and refeeding on tissue and serum metabolic enzyme activities and glycogen contents of Oplegnathus fasciatus with an average weight of(10.0±1.0) g.Five experimental groups were designed,i.e.fed twice daily for 30 d(S0,control group),starved for 3d and refed for 27 d(S3),starved for 6d and refed for 24 d(S6),starved for 9d and refed for21 d(S9),starved for 12 d and refed for 18 d(S12).The samples(serum,liver and muscle)were collected at the initial experiment,after starvation and refeeding,and the alkaline phosphatase(AKP),acid phosphatase(ACP),glutamicpyruvic transaminase(GPT),glutamicoxaloacetic transaminase(GOT)activities and glycogen contents of tissues were analyzed.The results showed that,serum and liver glycogen contents were significantly affected by the starvation and refeeding,and serum glycogen(except S12 group)and liver glycogen contents were reduced significantly as a result of starvation,while the liver glycogen contents returned to the level of control group after refeeding.However,only a little effect on the muscle glycogen contents was found during the starvation and refeeding.During the period of experiment,the AKP and GPT activities of serum and liver were significantly affected by starvation,and after refeeding,both enzymes activities returned to the levels of control group.However,during the whole experimental period,the effects of starvation and refeeding on muscle AKP,ACP,GPT and GOT activities were very little.In conclusion,the serum glycogen content with a level of (2.65±0.33)-(3.70±0.36) mmol/L was essential to maintain the stabilization of body metabolism.The main metabolic enzymes in serum and liver were very important in maintaining the basic metabolism of O.fasciatus under the condition of starvation.

Abstract:Somatostatins(SS)play important physiological functions in vertebrate’s growth and development,which belong to a multiple gene family.In this study,the complete cDNA sequences of three distinct preprosomatostatins(PSSⅠ,PSSⅡand PSSⅢ)were isolated from Siniperca chuatsi brain and cloned by means of rapid amplification of cDNA ends(RACE).The full length of PSSⅠ cDNA was 647 bp,which contained 369 bp open reading frame and encoded 122 amino acids with a signal peptide of 26 amino acids.It contained the conservative SS-14 sequence at the Cterminal extremity,which is identical with that of other vertebrates.The full length of PSSⅡ cDNA was 655 bp,which contained 387 bp open reading frame and encoded 128 amino acids with a signal peptide of 25 amino acids.It contained［Tyr⁷,Gly¹⁰］SS-14 at the C-terminal extremity.The full length of PSSⅢ cDNA was 823 bp,which contained 333 bp open reading frame and encoded 110 amino acids with a signal peptide of 21 amino acids.It contained［Pro²］SS-14 at its C-terminal extremity.PSS mRNA expressions in different adult tissues were analyzed by RT-PCR technique.All PSS mRNA were found in brain,while PSSⅠ mRNA wasn’t detected in other peripheral tissues,high levels of PSSⅡ mRNA were also present in esophagus and stomach,PSSⅢ mRNA in kidney and gonad.These suggested that all PSSs participate in neurological regulation in brain,whereas PSSⅡ may also regulate digestion activity,and PSSⅢ regulates reproduction activity.Cellular localization of PSS mRNAs in brain was determined by in situ hybridization,PSSⅠ mRNA was expressed in hypothalamus and medulla oblongata,PSSⅡ mRNA was expressed in hypothalamus,PSSⅢ mRNA was expressed in hypothalamus,optic tectun,medulla oblongata and spinal cord.All PSS mRNA were detected in the hypothalamus,which showed they could be involved in hypothalamic-pituitary regulation.Distinct expression in other brain sections suggested somatostatins may also act as neurotransmitters or hormones,and exhibit different biological effects.

Abstract:In this paper,shrimps of Fenneropenaeus chinensis with the body weight of(0.33±0.020 4) g(SF group)and(2.07±0.184) g(MF group)respectively and Marsupenaeus japonicus with(0.25±0.018 1) g(SM group)were fed with gammarid Ampithoe valida to determine the effects of gammarid on growth and antidisease ability of the shrimps.The results were as follows:(1)Compared with shrimp pellet feed,gammarid can improve SGR of shrimps in MF and SM groups and can improve survive rate of shrimps in SM group too.(2)Gammarid can raise the total number of blood cells of shrimps in SF and SM groups significantly(P＜0.05).(3)Gammarid can improve total protein level in blood of three shrimp groups significantly(P＜0.05)and can also improve hemocyanin of shrimps in SF and SM groups significantly(P＜0.05).(4)Gammarid can improve activity of LSZ of M.japonicus.(5)Gammarid can improve activity of PO and SOD of shrimps in MF and SM groups significantly(P＜0.05).(6)Gammarid can improve the relative activity of POD of shrimps in SF and SM groups significantly(P＜0.05).(7)There is a linear relationship between the total score of healthy index and the time during which shrimps were all killed by WSSV(R²=0.948 9).The results show that:Gammarid can improve growth and antidisease ability of the F.chinensisandM.japonicuscompared with pellet feed and the best time for gammarid as nature food is when the shrimps are larvae.

Abstract:A small amount of yellow shell color of small abalone were found in the stock of “Dongyou No.1”.In order to understand the relationship between shell color and growth traits,four different color lines of Haliotis diversicolor including BB(normal♀× normal♂),YY(yellow♀× yellow♂),YB(yellow♀× normal♂)and BY(normal♀× yellow♂)were established by inbreeding and crossbreeding.The biological parameters of egg dismeter,fertilization rate,hatching rate,metamorphosis rate,survival rate and growth traits among different shell color lines were studied.Genetic diversity and genetic structure for the four lines were compared using 16 microsatellite markers.The results showed that yolk diameter of yellow shell color line was significantly larger than that of normal shell color line(P<0.05).Egg diameter,fertilization rate,hatching rate,metamorphosis rate and survival rate showed no significant differences(P>0.05)among BB,YY,YB and BY lines.At 90 days after fertilization,the growth of shell length and width among the four lines showed no significant differences(P>0.05).The results also showed that BB line had the lowest genetic diversity.In addition,Nei’s genetic identity(0.632 9-0.957 1)and genetic distance(0.043 9-0.457 3)indicated that genetic identity between BB and YY(0.632 9)was the lowest and genetic distance between them was the farthest(0.457 3).The results indicated genetic differentiation exists between normal and yellow color individuals.The present study provides basic data and theoretical basis for selective breeding of the small abalone using shell color as a candidate marker.

Abstract:Vibrio harveyi is known to be a major pathogen in mariculture animal systems.Disease outbreaks attributed toV.harveyi have been reported in main mariculture animal farm production.In recent years,mass mortalities of many cultured kinds of maricultured fishes,such as Litopenaeus vannamei,Pseudosciaena crocea,and Lutjanus sanguineus have occurred frequently infected by V.harveyi. In this article the 101 isolates of V.harveyi were subjected to random amplified polymorphic DNA(RAPD)-PCR and BOX-PCR analysis to investigate the genetic variability among V.harveyi strains.A total of 10 RAPD primers were designed for their specificity in detecting V.harveyi,and only the primer PM2 was highly reproducible and found suitable to use in RAPD-PCR.The genetic diversity among V.harveyi isolates assessed by RAPD-PCR by PM2 primer yielded 15 different RAPD patterns which clustered the isolates into 18 groups at 65% similarity level.Similarly,BOXPCR clustered the 20 patterns into15 groups at 40% similarity.However,with RAPD-PCR and BOX-PCR,101 V.harveyi could be divided into 18 groups at 50% similarity.We could obtain the accurate results of molecular genetic diversity by both RAPD-PCR and BOX-PCR.

Abstract:Dominant bacteria (SX1) were isolated from diseased and dead megalopas Portunus trituberculatus, and have pathogenicity to healthy megalopa and juvenile (Ⅲ) crab Portunus trituberculatus by artificial challenge. The phenotypic characteristics of the isolates including morphological, physiological and biochemical characteristics were determined. The 16S rRNA and two housekeeping genes, RNA polymerase a-chain (rpoA) and DNA gyrase B subunit (gyrB) were sequenced, and the phylogenetic trees based on 16S rRNA and gyrB sequences were constructed as an aid to identification. The sequenced 16S rRNA gene of strain SX1 (GenBank accession No. JQ394838) was 1454bp, the gyrB gene of strain SX1 (GenBank accession No. JQ394839) was 1077bp, the rpoA gene (GenBank accession No. JQ394840) was 913bp. The 16S rRNA, gyrB and rpoA genes were compared with sequences deposited in databases, molecular phylogenetic analyses were conducted. The results showed that the characteristics of identified strain (SX1) consist with genus of Photobacterium, and the 16S rRNA, gyrB and rpoA genes of the identified strain (SX1) exhibited high similarity with Photobacterium sp., the phylogenetic trees constructed using the neighbor joining method based on 16S rRNA and gyrB genes, strain SX1 clustered with the Photobacterium ganghwense, and was supported by a higher bootstrap value. Therefore, strain SX1 was similar with P.ganghwense. The results confirmed that the diseased megalopas were infected by P.ganghwense. To our knowledge, this is the first report of P.ganghwense as pathogenic bacteria of crab.The study showed the diversity and complexity of pathogenic bacteria from aquatic animals.

Abstract:To improve the oyster phenotypic character,9 Crassostrea gigas families(HH₁₁,HH₁₂,HH₁₃……HH₃₃),9 C.hongkongensis families(GG₁₁,GG₁₂,GG₁₃……GG₃₃)and 45 interspecific hybrid families(C.hongkongensis♀ ×C.gigas〖QX(Y10〗♂〖QX)〗)(HG_{11,HG12,HG13……HG153)were established by the method of unbalanced nest design(one male to three female)in July 2010.Moreover,their early phenotypic character,heterosis potence and heterosis were examined under the identical conditions.These results show that the hybrid weakness of fertilization and hatching levels(hp＜-1)were observed among interspecific hybrid families due to the gametal incompatibility and individual variation.On the whole,the outbreeding depression of larvae growth was observed with the significant hybrid weakness(hp＜-1); the heterosis potence of larval survival ranged from -1 to 1,and survival advantage occurred without the remarkable level; the significantly metamorphic heterosis(hp＞1)was investigated during the planktonic stage.Cytology and molecular biology of interspecific hybridization were further researched on the base of numerous hybrids with genetic information.}

Abstract:Sea cucumber Stichopus japonicus has become an important cultivated aquatic species in China in recent years.Previous studies mainly focused on the food sources,nutrition values,biological activity and structure of acid polysaccharide.However,these studies do not have a tissue structural consideration on sea cucumber meat.In this paper,the changes of muscle tissue and collagen fibers structure from S.japonicus during heated treatment were studied,and the variation mechanism was analyzed.The structures of muscle tissue and collagen fibers were observed by a light microscope and a scanning microscope,meanwhile DSC tested the denaturation temperature of sea cucumber.Following were the results.The changes of tissue structure and collagen fibers after heating treatment were evident.Along with the increasing of heating temperature,the muscle fibers gradually aggregated and crosslinked,forming porous mesh structure.The collagen fiber structure shrunk,accompanied with collagen protein denaturation leading to fibers closely spaced.The changes of collagen fibers structure were more prominent compared with the overall tissue structure.DSC scanning curve of rawS.japonicus meat showed the denaturation temperature was 68.92 ℃.Thermal denaturation of muscle protein during heating treatment resulted in the changes of tissue structure and collagen fibers.

Abstract:Octopus vulgaris,which owns a number of unique stress protection mechanisms is considered to be the most intelligent species of all invertebrates.A 2 709 bp fulllength cDNA sequence of heat shock protein 90(HSP90) gene from O.vulgaris was obtained by homologous amplification and rapid amplification of cDNA ends(RACE).It consisted of a 119 bp 5′untranslated region(UTR),a 2 136 bp open reading frame(ORF)and a 454 bp 3′UTR.The inferred amino acids sequence was composed of 711 amino acids,whose molecular weight and isoelectric point were 81.5 ku and 5.09,respectively.Homologous analysis showed the inferred amino acids sequence was highly conserved and contained five classicalHSP90 signature sequences.Realtime quantitative PCR(RT-PCR)results displayedHSP90 expressed in every tissues chosen,with the most in liver.This study which was the first time to obtainHSP90 gene from Cephalopod played an important role in studying stress mechanisms on the most intelligent invertebrate.

Abstract:Follicle-stimulating hormone(FSH)controls gonadal function in mammalian and many non-mammalian vertebrates through the interaction with their receptors(FSHR).Molecular cloning of the yellow catfish FSH receptor is reported together with changes in the gene expression throughout a reproductive cycle.This work describes the molecular cloning of the cDNA encoding the folliclestimulating hormone receptor(FSHR)of yellow catfish(Pelteobagrus fulvidraco)by means of reverse transcriptase polymerase chain reaction(RT-PCR),degenerate primers PCR amplification and 5′ and 3′ rapid amplification of cDNA ends(RACE)analyses.We cloned the complete cDNA sequence ofFSHRgene and the length is 2 340 bp,encoding a protein of 661 amino acids.This gene belongs to G proteincoupled receptor(GPCR)family,which contains the seven conserved transmembrane helix(TM helix)domains.We found that the amino acids sequence contains nine Leucinerich repeats(LRRs),five potential Nlinked glycosylation sites and that only one protein kinase C phosphorylation site is ⁴⁰³Y in ELⅠ(extracellular loop,ELⅠ)and three protein kinase C phosphorylation sites are ⁶³⁴S,⁶⁴³S,⁶³²T in C-terminal domain.The areas played the important role in the function ofFSHR gene.The tissue distribution pattern showed high expression of FSHR gene in ovary and brain,and trace amount was detected weakly in other tissues.We also analyzed the mRNA expression level of FSHR gene in ovary at different stages of reproductive cycle.Result showed that the transcript level ofFSHR gene was high from Ⅲ to Ⅳ phases then followed by a substantial decline.These changes in expression profiles may imply differences in the functionality of the enzyme gene between different stages,suggesting an important role of FSHR gene in yellow catfish development.We inferred that the gene of FSHR in ovary might also be involved in the processes which regulate ovulation maturation and ovulation,and preferentially promote vitellogenin accumulation.The result has provided an improtant theoretical basis for the function ofFSHR gene and the breeding of yellow catfish.

Abstract:In order to explore the molecular regulation mechanism of Na⁺,K⁺-ATPase(NKA)α-subunit in gills of juvenile Chinese sturgeon at salinity 10,partial NKA α-subunit gene sequence was cloned,and the abundance of α-subunit mRNA,NKA activity,ion concentration and osmolality were examined at 3,6,12,24,48,72,96 hours post-transfer.Results showed that:in experimental group(fresh water-salinity water,FW-SW),the expression of NKA α-subunit mRNA and NKA activity increased significantly(P<0.05)during the adaptation phase(0-12 h),and the concentration of Na⁺,Cl^-and osmolality rose to a maximum level at 12 h post-transfer.In regulatory phase(12-24 h),the amounts of NKA α-subunit mRNA and NKA activity fell to a relatively lower level which was still higher than that of fish in control group(P<0.05).The change both in ion concentration and osmolality were in accordance with the change of NKA and mRNA expression.In conclusion,gill Na⁺,K⁺-ATPase in Chinese sturgeon plays an important role in osmolality regulation by changing αsubunit mRNA expression.The different α-subunit mRNA expression can lead to the variation of enzyme activity which can further regulate the ion concentration and osmolality.

Abstract:To evaluate the physiological responses and changes of swimming crab,Portunus trituberculatus between pre- and post-maturity at different salinities(15,20,25,30 and 35),the oxygen consumption rate(OCR),ammonia excretion rate(AER)and respiratory enzyme activities including hexokinase(HK),pyruvate kinase(PK),succinate dehydrogenase(SDH)and lactate dehydrogenase(LDH)were measured in this study.Results showed that the interaction of salinity and size did not influence the respiratory metabolism significantly.Salinities had a significant effect on AER other than OCR.Marked differences were found in both OCR and AER between pre and postmaturity individuals(P<0.05).No significant difference of O∶〖KG-*2〗N ratio was found among different salinities(P>0.05),however,O∶〖KG-*2〗N ratio in prematurity individuals was significantly higher than that in postmaturity individuals(P<0.05).It was noticed that the activity of HK and PK changed significantly with size rather than salinity(P<0.05).Excluding LDH,no significant correlation between respiratory metabolism enzymes and salinity was observed(P>0.05).However,the respiratory enzymes in tested tissues changed significantly between pre and postmaturity(P<0.05)except SDH and LDH in gills(P>0.05).The study indicated that compared to salinity,body size more impacted the respiratory metabolism of P.trituberculatus.And it is suggested that long-term salinity acclimatization could lower or eliminate the difference of respiratory metabolism ofP.trituberculatusat different salinities.