Abstract:Studies were conducted to reveal the changes in growth, serum biochemical indices and growth hormone (GH), insulin-like growth factor Ⅰ(IGF-Ⅰ) and insulin (IN) mRNA expression abundance of Nile tilapia (Oreochromis niloticus) during fasting and re-feeding. Nile tilapia with initial body weight (62.50 ± 3.44) g were starved for 28 d and then fed for 21 d under controllable indoor environment. Fish were sampled at 0, 7, 14, 21 and 28 d during fasting and at 14 and 21 d during re-feeding, respectively. The results indicated that the body weight was significantly decreased when fasting over 7 d (P<0.05), and significantly increased when re-feeding for 21 d (P<0.05). The hepatosomatic index was significantly decreased throughout the experiment (P<0.05). Significant reduction was observed in the content of triglyceride and glucose, and in the activities of alkaline phosphatase, glutamic oxaloacetic transaminase and glutamic pyruvic transaminase after fasting (P<0.05); After re-feeding, the value of these indices increased in varying degrees, but the activity of transaminase was significantly lower than initial value(P<0.05). There was no change in total cholesterol, high density lipoprotein cholesterol or low density lipoprotein cholesterol during the experiment (P>0.05). Serum GH and liver GH mRNA levels showed significantly up-regulation, whereas significant down-regulation was observed in serum IGF-Ⅰ and liver IGF-Ⅰ mRNA levels after fasting, and after re-feeding both of them increased (P<0.05). IN mRNA level was significantly increased during fasting for 7-21 d (P<0.05), but its level was not obviously changed when fasting for 28 d (P>0.05), then was significantly decreased after re-feeding (P<0.05). The present study revealed that fasting could restrain the growth of O. niloticus, promote serum triglyceride and glucose breakdown, and decrease the activity of transaminase. Serum GH/ IGF-Ⅰ and liver GH/ IGF-Ⅰ mRNA expression abundance displayed synchronous changes and the liver IN mRNA expression abundance was significantly increased when fasting for 7-21 d and then decreased to normal level when fasting for 28 d. It suggests that the level of GH / IGF-Ⅰ gene transcription of O. niloticus may be the most important factor in determining the levels of hormone in serum, while down-regulation of serum insulin may be due to its release reduction in islet when fasting.

Abstract:Based on northern largemouth bass and florida largemouth bass, four populations including selfing of N(Micropterus salmoides salmoides ♀×M. s. salmoides♂) and F(M. s. floridanus ♀×M. s. floridanus♂), direct cross NF(M. s. salmoides♀×M. s. floridanus♂) and FN(M. s. floridanus♀×M. s. salmoides♂) were established. Further comparative analysis of growth and morphological characteristics were carried out between parents and their reciprocal hybrids. The results were as follows. The growth rates had no difference between N, NF and FN on 152nd day. After 152 days the northern largemouth bass grew more rapidly than two hybrids. As meristic characters, the numbers of soft ray of pelvic, spine of anal fin, gill raker and vertebra were consistent in these four populations, and the chi-square analysis of meristic characters showed highly significant differences between parents and hybrids in soft ray of dorsal, soft ray of pectoral, soft ray of anal fin, soft ray of tail fin, scales above lateral line and scales below lateral line. The results of cluster analysis have revealed that the morph metric characters of N and F were much closer, the same to the reciprocal hybrids groups. Three principal components with accumulative variance percentage 71.44% were summarized in principal component analysis. The principal components 1, 2 and 3 reflected the morphological variations of frame, head and caudal peduncle, with the variance percentage being 54.90%, 11.20% and 5.33%. In discriminant analysis, 11 parameters were selected from 35 measured parameters to establish discriminant functioned of the populations. Discriminant accuracy was 83.90%—100.00%. This study would be beneficial to the identification, breeding and aquaculture of largemouth bass.

Abstract:In this study a gonadotropin-releasing hormone (GnRH)-like peptide was partially isolated by reverse phase high performance liquid chromatography (RP-HPLC) from the brain extract of Chinese mitten crab Eriocheir sinensis. Immunological dot blot analyses from RP-HPLC fractions using the anti-octGnRH revealed that one of fractions is immune reaction positive, suggesting that the fractions of brain extract contain GnRH-like substance. Eight kinds of small peptides, with molecular weight ranging from 800 to 1 400 u, were further identified in this fraction by using matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF/TOF MS). One of peptides in MS component shared similar molecular weight with the octGnRH.

Abstract:Hybrid vigor among three geographical populations of Megalobrama amblycephala, including Liangzi Lake population (L), Poyang Lake population (P) and Yuni Lake population (Y), was predicted by combination ability and SSR markers. The first generation individuals of 9 complete diallel cross combinations of three populations were measured with total length and body weight. The analysis of combination ability showed that the sire of Yuni population had the largest general combining ability effective value; however, the largest general combining of total length in dam was Poyang population, while that of body weight was Liangzi population. There were high effective combinations among P♂×P♀, L♂×Y♀ and Y♂×Y♀ which had high specific combining ability, so these combinations were suitable as basic selective populations. The results obtained from SSR markers showed that all three populations had high genetic heterogeneity (He, 0.877-0.863), polymorphism information content (PIC, 0.848-0.820) and marker index (MI, 8.959-11.242). Among the three populations, Liangzi population and Yuni population revealed the largest genetic distance, reaching 0.336 2. According to the result, L♂×Y♀ would have the highest hybrid vigor among those combinations.

Abstract:Salinity, calcium and magnesium play key roles in the survival and growth of Litopenaeus vannamei. In the present study, two experiments were conducted to test the effect of salinity, calcium and magnesium on survival, growth and flavor of the shrimp, L. vannamei. The first experiment designed using the Taguchi method with three factors (Ca2+, Mg2+ and salinity), each with 7 levels (L49), was run for 60 days to analyze the independent role of Ca2+, Mg2+ and salinity on the survival, growth and flavor of L. vannamei. Additionally, a L8 test of three factors, each with two levels, was conducted to analyze the interaction of Ca2+, Mg2+ and salinity on the survival, growth and flavor of L. vannamei. The results showed that Ca2+, Mg2+ and salinity significantly affect the survival and flavor amino acids of L. vannamei, and Ca2+ and Mg2+ significantly influence the growth. The highest survival rate was observed at Ca2+ of 100 mg/L and 400 mg/L, Mg2+ of 1200 mg/L, and salinity of 10; The growth did not significantly change at Ca2+ of≥200 mg/L, and Mg2+ of ≥300 mg/L. The highest length and weight gains were found at Ca2+ of 100 mg/L, Mg2+ of 150 mg/L and salinity of 10-20; The content of flavor amino acids increased with the increase of Ca2+, Mg2+ and salinity, and the highest content of flavor amino acids occurred at Ca2+ of 400 mg/L, Mg2+ of 750 mg/L, and salinity of 20 and 35. Low salinity and concentration of Ca2+, Mg2+ significantly reduced the growth and survival of the shrimp. The interaction between Ca2+ and Mg2+ was significant on survival and daily weight gain of the shrimp, and the combined effect of Ca2+ and salinity was significant on survival of the shrimp. However, the interaction between Mg2+ and salinity was not significant on any of the three parameters.

Abstract:In this study, microsatellite markers were developed from the BAC-end sequences and used to analyze the genetic structure and genetic differentiation in two populations in Zhikong scallop (Chlamys farreri). A total of 3 374 microsatellites were identified from the 17 477 BAC-end sequences (BESs), of which tetra-nucleotide motifs were most abundant (26.6%), followed by penta-nucleotide motifs (17.7%) and hexa-nucleotide motifs were the least (12.0%). 77.3% SSRs were successfully amplified(99/128), and 43 SSRs(33.6%) were polymorphic in the parentage of mapping population. In order to apply these BES-SSR markers, 14 polymorphic SSRs were chosen to amplify and then analyze the genetic diversity in Dalian population and Qingdao population. A total of 395 alleles were obtained at the fourteen microsatellite markers and the number of alleles in each locus ranged from 8 to 38 in the two populations. The average number of alleles (Na) was 18.928 6 and 26.214 3 respectively. The average effective number of alleles (Ne) was 11.750 5 and 17.089 1 respectively. The mean observed heterozygosity (Ho) was 0.510 0 and 0.420 4. The mean expected heterozygosity (He) was 0.915 6 and 0.945 0. The data suggested both populations have high genetic diversities. The mean polymorphic information content (PIC) was 0.894 0 and 0.930 2, which were both greater than 0.5, indicating the fourteen loci were highly polymorphic. The unbiased genetic identity index was 0.487 9, and the genetic distance was 0.717 7. The coefficient of gene differentiation (FST) and gene flow (Nm) between two populations were 0.024 3 and 10.017 9 respectively. Low genetic differentiation was observed between the two populations, and the variance mainly came from individual difference. Significant deviation was detected by Hardy-Weinberg equilibrium test. There was heterozygote deficiency at all loci. The results showed BAC-end sequences were an effective resource for development of SSR markers for genetic and genomic researches.

Abstract:Outbreaks of blue algae bloom in Taihu Lake have occurred frequently since 2006. Lots of blue algae appeared along the shore of south Taihu Lake from July to November every year, and the highest concentration of algae in water could reach more than 170 million per liter in 2007 and 2008. The worsened water environment, especially during the period of severe eutrophication, not only made the lake basin be faced with the risks of the shortage of high quality drinking water, but also caused the lake reduction of fish species and appearance of smaller, younger or trash fish. South Taihu Lake generally refers to the areas located along the part of the lake in Zhejiang Province, and the water quality data available is very limited compared with those of east or north Taihu Lake for the future concern on the issue. An annual variation of blue algae biomass, NH4+-N and TN levels at Xiaomei, Xintang and Daqian inlet areas of south Taihu Lake was determined at regular intervals so as to find out the water quality conditions and the variation regularity between the blue algae biomass and ammonia nitrogen (NH4+-N) or total nitrogen (TN). The correlation between the blue algae biomass and NH4+-N or TN was analyzed by SPSS 10.0. The results showed that: (1) the blue algae biomass at different inlet areas had two peaks, one in May-June, and the other in September-October each year; (2) water quality was in eutrophic phase due to the high TN level; (3) the correlation coefficient (r) between biomass and NH4+-N level was -0.102 to -0.290, indicating not correlated; (4) the r value between biomass and TN level in 2008—2009 was -0.010 to 0.210, indicating not correlated; and with the r value of -0.430 to -0.474 in 2010, meaning lowly-negative correlated. Attention should be paid to the high nitrate level at different inlet areas of south Taihu Lake. The lake in high concentration of NH4+-N and TN, might provide the conditions for growth and reproduction of blue algae, but in the case of the outbreaks of blue algae bloom, NH4+-N and TN concentrations would decrease rapidly. In south Taihu Lake basin exists the wane and wax regularity between the blue algae biomass and NH4+-N or TN. And the above-mentioned results could provide the necessary data for the analysis of the time and conditions of blue algae bloom in south Taihu Lake and make it possible to provide early warning information for the outbreak of blue algae bloom and water quality deterioration.

Abstract:The bloody clam, Tegillarca granosa, is an important commercial bivalve which is extensively cultured from South Korea to Malaysia. Due to its economic value, it is important to cultivate rapid growth strains for the sustainable development of aquaculture industry of T. granosa. The emergence of molecular markers provides a rich theoretical basis for the rapid cultivation varieties. By the method of group selection, the rapid growth strains of T. granosa were bred though two generations. According to the comparison test, the rapid growth strains showed significant advantages in shell length, shell height, shell width and total weight than control group under the same environmental conditions. AFLP marker was applied in this study to evaluate the genetic variation of the rapid growth strains, and to screen the molecular markers associated with the traits of growth. A total of 2180 bands were amplified from 64 individuals of the rapid growth strain and control group by 40 primer combinations. The analysis of Nei’s genetic diversity index and Shannon’s genetic information index of two groups indicated that the genetic diversity of breeding group was slightly higher than the control group. The genetic distance between two groups was about 0.011 3, the value of GST was 0.022 4 and Nm was 22.281 1, from which we concluded that there is a little genetic differentiation after selection. Of all amplified bands, 7 bands showed significant differences in frequency between two groups. 2 bands of all were only found in rapid growth strains, with the frequency of 0.812 5 and 0.343 8, respectively. And 2 bands showed significantly higher frequencies in rapid growth strains, while 3 bands showed significantly higher frequencies in control group. The bands with higher frequencies in rapid growth strains may be associated with the traits of growth. The unique AFLP markers associated with growth traits would be useful for growth-related gene cloning, quantitative trait locus (QTL) mapping, and molecular-assisted selection (MAS) of T. granosa.

Abstract:Toll receptor is a kind of transmembrane protein. The extracellular domain of Toll receptor can recognize the highly conserved components of pathogens, termed pathogen-associated molecular patterns (PAMPs), which is only expressed on pathogen microbe. The signal on pathogen invasion is transmitted into cell by Toll receptor and then induce cascades on production of immune effectors and immune reactions. Toll receptor is vital for innate immunity of organism. The existence of Toll receptor has been verified in some kinds of shrimp. But the application of Toll receptor in nutrition-immunity study of shrimp is scarce. This paper reviews the signal pathway of Toll and research advance on prawn Toll. The application of Toll receptor in nutrition-immunity assessing on prawn is also elucidated. The variation on expression of Toll receptor gene may reflect the sensitivity of organism to invading pathogen. Expression of Toll receptor gene should be a valuable parameter for assaying nutrition-immunity of shrimp. However, more research should be conducted in future to interpret the effects of dietary nutrients on expression of Toll receptor gene. Whether expression of Toll receptor gene of shrimp could reflect the immunological function of the diet should also be studied.

Abstract:Four inbred families named AB, Ab, aB and ab were obtained using diallel cross between large(♀A, ♂B) and small(♀a, ♂b) sizes selected from a fast-growing family depending on standard of shell length. Growth and metamorphosis were analyzed at the stages of larval and juvenile. The results showed that growth sequence of inbred families was AB>Ab>aB>ab, and AB grew faster than ab with significant difference ( P<0.05), except day 9. Every group began to metamorphose at day 6, the metamorphosis rates of AB was 71.12%±1.53% which was higher than ab (41.6%±1.33%) (P<0.05). Distribution frequency of shell length of four experimental groups has changed by inbreeding within family. The size of AB obtained from up-selection verged on becoming large; however, ab obtained from down-selection verged on miniaturization. In conclusion, up-selection within families is the effective method for the genetics improvement of Manila clam.

Abstract:In recent years cultured sea scallop (Patinopecten yessoensis) dead on a large-scale in seas near Changhai County, Dalian, China, in summer. The main symptom is the abscess on adductor muscle. The transmission experience was improved to indicate that a bacterium isolated from natural infected focus, named XJ02 displayed intense pathological activity to scallops, and the symptom is the same to natural intention. The bacterium XJ02 identification test through morphological specificity, physical and chemical properties and 16S rRNA gene sequence analysis showed the bacterium is Vibrio chagasii. There has been no any research on the pathogenicity of V. chagasii. This article for the first time to find a more comprehensive's vibrio physicochemical properties of research. The dose-and temperature-dependent test indicated that the bacterium had the most pathogenicity at 19 ℃ while the concentration was 1.09×105 CFU/mL. The medicine sensitivity analysis that￠s to check Ampicillin, Benzylpenicillin, Ciproflxacin etc is sensitive during 20 drugs sensitive test, to Tetracycline, Doxycycline is not sensitive element.

Abstract:Full-length cDNA of IgM haevy chain of cobia (Rachycentron canadium Linnaeus) was amplified by the techniques of Rapid Amplification of cDNA ends (RACE) and PCR, and expression of target gene was analyzed by the method of real time RT-PCR in different tissues. The full-length cDNA of μ of cobia is 1 933 bp, with a 5￠terminus untranslated region (UTR) of 26 bp and a 3￠terminus UTR of 164 bp, carried an open reading frame (ORF) of 1 743 bp, encoding 580 amino acids with estimated molecular weight of 64.83 ku and the theoretical isoelectric point of 6.6. The similarity of the deduced Igμ amino acid sequences of cobia was less than 30%, when compared with those of other animals. Moreover, similarities of the conservative CH4 region of cobia,to other fish were 64%-71%. But, to other living things, similarity was only 31%-33%, having a strong specificity. Clustal X analysis indicated that there existed conserved amino acid sites (cysteines, tryptophans) and two E-box motifs GKGLEW at framework region two and YYCAR at framework region three, respectively in the IgM heavy chain of cobia. Ig μ gene was expressed in all the tissues but kidney in healthy cobia and the expression with the highest quantity was present in intestine by real time RT-PCR. The target gene was respectively expressed in all tissues of cobia after stimulation by intraperitoneal injection with Vibrio carchariae for 48 h, 96 h and 192 h. The expression of Igμ gene was significantly increased in heart, gill and intestine after 48 h. Increased expression of gene in spleen, stomach, brain was after 0 h and in liver, head kidney and kidney was after 192 h. Conclusion could be drawn that mucosal immune defended against foreign pathogens as the first barrier, followed by the liver, spleen, kidney, head kidney immune response, which indicated that immune system plays an important role in defense against foreign pathogens for a long time.

Abstract:This paper is to study the release characteristics of doxycycline (DC) raw material drug and doxycycline chitosan nanoparticles (DC-CS-NPs) freeze-dried powder in vitro and in vivo by ultraviolet spectrophotometry and ultra performance liquid chromatography, respectively. Results showed that the release behaviors of DC raw material drug were simulated the most in the zero order dynamic equation in artificial gastric juice, artificial intestinal juice and pH 7.4 buffer phosphate. The release of DC raw material drug was fast which could completely dissolve in one hour; The DC-CS-NPs freeze-dried powder had a significant slow-release characteristic. The release behaviors were simulated the most in the biexponential equation. The drug released fast in the early stage while it released slowly later. The order of release speed of DC-CS-NPs freeze-dried powder from fast to slow was pH 2.0 artificial gastric juice, pH 3.0 artificial gastric juice, pH 4.0 artificial gastric juice, artificial intestinal juice and pH 7.4 buffer phosphate. When DC raw material drug became DC-CS-NPs freeze-dried powder, after a single oral administration at a dose of 20 mg/kg at (25±1) ℃, the double-peak phenomenon of plasma in channel catfish was turned into single-peak, and the pharmacokinetic parameters of DC-CS-NPs freeze-dried powder were changed. Compared to DC raw material drug, the peak concentration (Cmax) decreased. The peak time (Tmax) and terminal elimination half-life (T1/2β) prolonged. The area under concentration-time curve (AUC) was larger. The DC-CS-NPs freeze-dried powder will become an ideal DC new formulation.

Abstract:TypeⅠcollagen, as a number of collagen family, is the most abundant collagen and major components of the extracellular matrices of all metazoan life, and plays crucial roles in differentiation, formation of collagen fibers and tissue remodeling after injury, etc. TypeⅠcollagen alpha 1(COL1A1) cDNA of grass carp (Ctenopharyngodon idella) was isolated through the RT-PCR and RACE approaches. The cDNA was 5 772-bp in length, including a 4 347-bp CDS (coding sequence) and encoded a polypeptide of 1 449 aa. The homology of COL1A1 amino acid with relative species (zebrafish, goldfish, etc.) was as high as 93% with zebra fish and goldfish. The protein peptide molecular weight was 137.2 ku and theoretical pI was 5.44 using ProtParam software on line. The protein peptides of COL1A1 possessed 6 α-helixes, 12 β- sheets, others of ruleless coil regions, and 18 regions of triple helical repeats, 22 low complexity regions, 17 function domains. There were two calcium-binding sites and one zinc-binding site in the COL1A1 protein peptide. COL1A1 mRNA was determined in all the tested 8 tissues (muscle, intestine, hepatopancreas, gill, skin, fin, kidney and spleen) of grass carp by semi- quantitative RT-PCR, and the mRNAs expression in gill, kidney, skin and fin significantly higher than other tissues (P<0.05). The structure and bioinformatics characteristics of the COL1A1 from grass carp may help to further?understand the?function of COL1A1?gene in the?repair?process of damaged tissue?in the?grass carp.

Abstract:The toxic effects of aflatoxin B1 (AFB1) on Litopanaeus vannamei were examined in terms of growth indices, body composition, hepatopancreas microstructure and biochemical indexes of haemolymph and hepatopancreas. Six isonitrogenous purified diets were fed to shrimp [initial mean weight (0.3±0.02) g] for 8 weeks in triplicate tanks connected to recirculating system. Diets contained different levels of AFB1 (0, 400, 800, 1 200, 1 600, 2 000 μg/kg). Crude protein of whole shrimp had no significant differences (P > 0.05). Body lipid tended to be higher within shrimp fed diets with higher AFB1 level (1 600 and 2 000 μg/kg). The lowest weight gain (304.67%) was found in shrimp fed with 1 200 μg/kg diet. However the shrimp fed with 2 000 μg AFB1/kg got the lowest survival rate (58.33%) and the highest weight gain. Enzyme activities generally indicated a downward trend. Total antioxidant capacity of hepatopancreas decreased significantly (P<0.05) in 2 000 μg/kg diet. The activity of GST, Na+, K+-ATPase and SOD in hepatopancreas reached minimum in shrimp fed with 1 600 μg/kg AFB1 diet, but GST of haemolymph was significantly higher than others (P<0.05). Histological study on shrimp fed more AFB1 exhibited histological changes. Besides, higher AFB1 residues in hepatopancreas were observed in shrimp fed with higher level AFB1. The most AFB1 residues in hepatopancreas were detected at 95.49 μg/kg in shrimp fed with 2 000 μg/kg. However, no AFB1 residue in muscle was detected in all groups.

Abstract:In order to establish the superiority, four different tilapia strains (GIFT tilapia, New GIFT tilapia, Egypt Nile tilapia and Red tilapia) were compared in the study. At day 100 tilapias in the treatment group were intraperitoneally injected with Streptococcus iniae suspension (2.95×108 /mL) to evaluate disease resistance of four different tilapia strains against S. iniae in terms of the serum biochemical parameters and hepatic HSP70 mRNA expression before and after infection. Another set of twenty fish taken from each tank was challenged with S. iniae using the same method as above, and the cumulative mortality of 4 strains was recorded at different times post infection. The results showed that GIFT tilapia and New GIFT tilapia were more sensitive to S. iniae at 96 h after infection, cumulative mortalities were 36.67% and 38.33% respectively. Egypt Nile tilapia was less sensitive to pathogen and no death occurred during the experiment. The levels of serum cortisol (COR) and glucose (GLU) and expression levels of HSP70 mRNA in GIFT tilapia, New GIFT tilapia and Red tilapia strains were highly significant(P<0.05), and the activities of glutamic-pyruvic transaminase (ALT), glutamic-oxaloacetic transaminase (AST)and lysozyme (LSZ) also increased, while serum alkaline phosphatase (AKP), triglyceride and cholesterol levels were significantly lower than those prior to infection (P<0.05). By utilizing the energy from resolved hepatin and lipid, the synthesis of hepatic HSP70 mRNA and levels of LSZ and globulin in Egypt Nile tilapia were improved, and thus the non-specific immunity strengthened. It is suggested that in the course of tilapia breeding, effective combination of the disease resistance with growth be conducted so as to guarantee sustainable development of the tilapia industry.

Abstract:Aminopeptidase N is a member of the peptidase M1 family, and plays an important role in the digestion of protein. In this study, a full-length cDNA of APN gene was cloned from Ctenopharyngodon idellus with RT-PCR and RACE techniques, and its mRNA expression profile at different tissues was analyzed by real-time PCR method. The full-length of cDNA sequence of APN had 3 258 nucleotides, including 27 nucleotides at 5’UTR and 552 nucleotides at 3’UTR. Its open reading frame(ORF) had 2 679 nucleotides encoding a 892-amino-acid peptide. The deduced amino acid sequences of APN gene from C. idellus displayed the highest similarity with Danio rerio (75.4%), but varied to other animals from 61.2% to 58.8%. The encoded protein molecular weight was predicted at 100.61 ku with pI at 5.14. Phylogenetic analysis showed that the sequence of APN gene was clustered with D. rerio as its closest neighbor, which shared a sequence similarity of 81.5%, and had lower similarity with other animals from 60.2% to 54.3%. The APN protein had one helix trans-membrane region, but its amino acid sequence of the region demonstrated a low homology relationship to other vertebrates. The abundances of APN mRNA assayed by real-time PCR were differentially expressed at different tissues with a gradient from higher to lower among the tissues of fore-intestine, hind-intestine, liver, mid-intestine, kidney, muscle, spleen and heart, respectively. However, the APN mRNA expression was relatively stable after incubation for 4 days. The effects of the circadian rhythms on APN expression of C. idellus showed that there was a time-dependent pattern at higher rhythm during 06:00-18:00 and lower rhythm during 18:00-06:00. Therefore, our study could serve as an important research tool to study the relationship between APN gene’s function and its structure, and investigate its molecular mechanism for protein degradation in vivo.

Abstract:In order to interpret the development mechanism of fish germ cells at a molecular level, a Spinibarbus caldwelli homolog of the zebrafish vasa gene, ScVHG(S. caldwelli vasa homolog gene), was cloned and characterized for use as a molecular marker for germ cells in this species. Analysis of the nucleotide sequence revealed that ScVHG comprises an open reading frame of 1 932 bps encoding 644 amino acids. The deduced amino acid sequence contained nine conserved motifs belonging to the DEAD-box protein family. The S. caldwelli VASA protein sequence showed high similarity to that of zebrafish (77%), Oreochromis niloticus(77%), Oncorhynchus mykiss(79%), Carassius auratus gibelio(90%), Monopterus albus(74%), Carassius auratus(89%) Thunnus orientalis(79%) and Ctenopharyngodon idellus(86%). In adult tissues, the ScVHG transcripts were specifically detected in ovary and testis. In situ hybridization analysis showed that ScVHG messenger RNA (mRNA) was detected in spermatogonia, but not in spermatocytes, spermatoblasts and sperms; During oogenesis, ScVHG mRNA was detected in all time phases from oogonia to oocytes. The earlier phase of oogenesis, the more ScVHG mRNA molecules were detected. The positive signals of ScVHG mRNA gradually weakened in the late phase of oocytes and finally these signals gathered round the cell edge. Consequently, consensus sequences, sequence similarity, and specific localization of ScVHG mRNA in the germ cells all suggest that ScVHG is the S. caldwelli homolog of the zebrafish vasa. Further, ScVHG can be used as a molecular marker for S. caldwelli germ cells.

Abstract:Oligosaccharides could induce some physiological responses in algae to defend attacks from pathogens. One of the earliest responses induced by oligosaccharides was so-called oxidative burst. This study has surveyed the recognition and oxidative burst response of Porphyra haitanenesis to agaro-oligosaccharide. Oxygen consumption was detected by an oxygen electrode. H2O2 concentrations in the medium were determined by measuring the dimerization of (p-hydroxyphenyl) acetic acid. The elicited oxidative burst was observed by loading the P. haitanenesis with redox-sensitive fluorescent probe dichlorohydrofluorescin (DCFH-DA). Gene expression level of NADPH oxidase (named Phrboh) was detected by real-time PCR. 2-AMAC labeled agaro-oligosaccharides were used to research the binding of agaro-oligosaccharide on algae. Results showed that two respiration peaks were observed after addition of 100 μg/mL agaro-oligosaccharide in P. haitanensis. Fourfold increase occurred in the first respiration peak 4 minutes after the addition, and fourteen times higher in the second response 10 minutes after the exposure to agaro-oligosaccharide. The accumulation of H2O2 in the culture medium was detected 5 minutes after challenged with agaro-oligosaccharide. The concentration of H2O2 reached its peak after 15 minutes, which was nearly ten times higher than control. The gene expression level of NADPH oxidase in P. haitanensis was up-regulated 3 minutes after the addition of agaro-oligosaccharide, suggesting that the synthesis of H2O2 was closely related to the activation of Phrboh. Based on the analyses of the fluorescence of redox-sensitive dye, activated oxygen species mainly accumulated around the plasma membrane. Under the fluorescent microscope, specific binding of 2-AMAC labeled agaro-oligosaccharide on cell plasma membrane was also observed, which indicated that there was recognition site of agaro-oligosaccharide on P. haitanensis plasma membrane. In summary, P. haitanensis could recognize agaro-oligosaccharide and respond with oxidative burst which was associated with the activation of NADPH oxidase.

Abstract:In this paper, the hemolytic and mice acute oral toxicity of a new antibacterial peptide APNT-6 with antibacterial lipopeptide surfactin, iturin and fengycin as the main components was evaluated. At first, hemolytic activity of the antibacterial peptide was studied in vitro; a 100-fold dilution of the antibacterial peptide was added to an Oxford cup placed on rabbit blood agar plate, after 37 ℃ overnight, the hemolytic activity was determined. The results showed that, 100-fold dilution of the antibacterial peptide in the Oxford cup formed 32 mm hemolytic circle on the plate medium, indicating that it has a strong hemolytic toxicity in vitro that is possible barriers to actual use. Meanwhile, a study for acute oral toxicity of the antibacterial peptide in mice was conducted, 60 male and female Kunming mice were randomly divided into six groups, with normal saline as a control, each group of mice was respectively fed 8, 40, 200, 1 000 and 5 000 mg/kg of the antibacterial peptide dose at one-time, within 7 d, observing toxicity body signs and death situation of mice and determining feed intake, water intake, weight gain and organ index, and examining pathological changes for the abnormal organs. The results showed that in each dose group of mice death and any signs of poisoning were not seen. The oral median lethal dose (LD50) is greater than 5 000 mg/kg body weight; feed intake and water intake of each group mice have no significant change; except that the highest dose group had slightly lower weight gain, there were no significant differences in weight gain between the other groups and the control group; the spleen, kidney, lung and cardiac index of each group had no statistically significant differences and liver index of more than 1 000 mg/kg dose group was higher compared with the control group; mice organs and tissues of each dose group have no obvious pathological changes. These results suggest that high doses of the antibacterial peptide by oral administration can not achieve an effective hemolytic concentration in mice; in accordance with the acute toxic standard of disinfectant, it really has no toxicity, and that oral administration of the antibacterial peptide in mice does not constitute significant acute toxic effects. Based on the above results, it can be concluded that the new antibacterial peptide APNT-6 has strong hemolytic toxicity in vitro, but no acute oral toxicity in mice.

Abstract:Food allergy is?a?representative?human?allergic disease,?which is mainly?caused?by?the protein in food. Up to date, however, there is only a few reports on aquatic?food?allergy. Tropomyosin(TPM) is the major allergen of eating seafood like shimp and crab to cause hypersensitivity. In this investigation, a TPM gene was cloned from the muscle tissue of shrimp, Marsupenaeus japonicus. Then the TPM was expressed in Escherichia coli and purified. Subsequently the specific antibody was raised using the purified fusion protein (GST-TPM). As revealed by Western-blotting, the TPM was ubiquitously expressed in shrimp tissues and with the highest expression in the muscle and the lowest in gill and skin. These results have laid the foundation?for the specific diagnosis and immunotherapy in shrimp hypersensititivity disease as well as the study on food desensitization.

Abstract:To survey salted-dried fishes characteristic flavor substances, the volatile compounds in four traditional salted-dried fishes, namely, karafuto-shishamo(Spirinchus lanceolatus), tigertooth croa- ker(Otolithes rube), little yellow croaker (Pseudosciaena polyactis)and hairtail(Trichiurus haumela)were extracted by solid phase microextraction(SPME) and further analyzed and identified by method of gas chromatography-mass spectroscopy(GC-MS). The results showed that the compositions and kinds of volatile compounds were different in the four salted-dried fishes. There were 105, 89, 88 and 72 different kinds of volatile compounds with more than 80% matching degree isolated and identified. The contents of major volatile compounds were aldehydes, alcohols, hydrocarbons, which accounted for 49.99%, 53.09%, 60.54%, and 86.18% of the total volatile compounds of the four salted-dried fishes respectively. The major odors of salted-dried fishes were confirmed as fishy, grassy-fatty which were in good agreement with previous investigations. 3-methyl butanal, hexanal, (z)-4-heptenal,?heptanal, benzaldehyde, octanal, nonanal, 1-penten-3-ol, 3-methyl butanol, 1-octen-3-ol, heptanol and trimethylamine, were found to be involved in the formation of characteristic flavour.

Abstract:Phycoerythrin (PE), phycocyanin (PC), allophycocyanin (APC), and chlorophyll a(Chl.a) are the four major photosynthetic pigments of Porphyra haitanensis. Their contents and ratio determine the blade color of Porphyra. In this study, the relative expressed levels of four pigment genes (Cpeα, Cpcα, Apcβ, and Chl.a) in different growth phases (early phase, bloom phase, and final phase) were determined using quantitative real-time PCR (qPCR) in one wild line and six pigment mutant lines of P. haitanensis. In all the lines, the relative expression levels of the four pigment genes were in the sequence: Apcβ>Cpcα> Chl.a>Cpeα. The expressed level of Cpeα varied significantly in the different phases in all the lines; however, the expressions of Cpcα, Apcβ, and Chl.a were stable in all phases in all lines. Furthermore, liner correlation and regression analysis indicated that the expression levels of the pigment genes had no relation to the pigment protein contents in any of the lines. In other words, the expression levels of the four pigment genes had no relation to the differences in blade color among the Porphyra lines. Based on these results, we speculate that the pigment mutation of P. haitanensis was induced by mutations in genes that affect the synthesis of the pigment proteins.

Abstract:In this study, we analyzed the lipid of viscera of Haliotis discus hannai. The total lipids of the abalone viscera were extracted using Folch method. Separated neutral lipids and phospholipids by Silica gel column chromatography. Different components of neutral lipids and phospholipids were separated by TLC, and the main components were prepared by TLC. The composition of fatty acids was analyzed by GC, derived with 10% H2SO4-CH3OH solution, then compared the composition of fatty acids of different components. The phospholipid content in Abalone viscera is up to 31.58%, the content of unsaturated fatty acids in the phospholipid is significantly higher than that in the neutral lipid. Phospholipids contain a certain amount of plasmalogen, especially in the phosphatidylethanolamine. The Abalone viscera is rich in phospholipids and unsaturated fatty acids, and it contains a certain amount of plasmalogen. The abalone viscera is the potential material for diet and medicine, which should be fully utilized．