Abstract:KK-42 pretreatment can promote the survival rate of Macrobrachium nipponense infected with Aeromonas hydrophila.In order to investigate the possible molecular mechanism of KK-42 action,the partial sequence of α2M gene was first cloned and the spatio-temporal expression of the gene as well as the effects of KK-42 on its gene expression and activity were measured.The prawns,3.5-5.0 cm long,were soaked for 1 min in KK-42 solution at a concentration of 1.95×10^-4 mol/L(KK-42 treatment)or 0(KK-42 control),respectively.The KK-42 treatment group was injected individually with A.hydrophila suspension(KK-42 treatment-A.hydrophila)or saline(treatment-1)into the ventral sinus at 12 h after KK-42 treatment and the KK-42 control group was divided into groups as control-A.hydrophila and control-1,according to the same way.Then the survival rate was surveyed at different time points,and the α2M mRNA level and activity derived from different tissues were measured.Results showed that the survival rate of KK-42 treatment-A.hydrophila dramatically increased by 133% than that of the control-A.hydrophila group.Sequence comparison indicated that the α2M deduced amino acid sequence of M.nipponense had an overall similarity of 90% to that of Macrobrachium rosenbergii.Real-time PCR analysis revealed that α2M was mainly expressed in haemocytes,and higher at premolt.Compared with the KK-42 control group,the changes of α2M mRNA level and activity from KK-42 treatment group were not statistically significant.In control-A.hydrophila group,the α2M gene mRNA level and its activity in haemocytes obviously increased by 580% and 47.5%,respectively,only at 3 and 24 h post-injection compared to 0 h.In KK-42 treatment-A.hydrophila group,the α2M mRNA transcripts were significantly higher at 6-48 h and reached the maximum at 12 h with an increase of 511% than that of control-A.hydrophila group.The change trend of α2M activity was basically similar to that of its expression.In conclusion,our present results indicated that KK-42 pretreatment could significantly up-regulate the α2M gene expression as well as its activity in haemocytes of M.nipponens infected with A.hydrophila.This might lead to the enhancement of immunity in the prawns,which was likely one of the molecular mechanisms of KK-42 acting for increasing survival rate of the prawns infected with A.hydrophila.

Abstract:The aquatic algae have developed a carbon dioxide concentrating mechanism(CCM)to acclimate to the CO₂-limiting environmental conditions,of which carbonic anhydrase is the major component.In order to explore the response pattern of carbonic anhydrase to environmental factors,and to improve the utilization of inorganic carbon and algal biomass of Chlorella,the effects of salinity,CO₂ and bicarbonate on the growth,extracellular carbonic anhydrase activity and 3 subtypes of ca gene expression level of C.pyrenoidosa were investigated by biochemical and real-time quantitative PCR methods in this study.Results showed that the alga grew faster cultured in 15 and 30 salinity,and the algal density in 45 salinity was 0.83-fold of that in 15 salinity on the 9^th day.The extracellular carbonic anhydrase activities were inhibited with the increasing salinity,which was especially obvious after long-time treatment with 45 salinity.However,the expression level of three subtypes of ca genes increased from 15 to 45 salinity,which could vary from 1.52-fold to 2.16-fold of that cultured in 15 salinity.The algal density cultured in double air CO₂(high CO₂ level)could reach 1.23-fold of that in air CO₂(low CO₂ level).But the algal CA activity in high CO₂ level was lower,which was only 0.41-fold of that cultured in low CO₂ level on the 8^th day.The α- and γ-ca mRNA accumulations in high CO₂ level were slightly higher,which were 1.22 times and 1.47 times that in low CO₂ level,respectively.The growth of C.pyrenoidosa was promoted when the bicarbonate concentration ranged from 0 to 10 mmol/L.And the algal CA activity showed maximum value in 5 mmol/L HCO₃^- group.The highest levels of α-,β- and γ-ca were observed in 1 mmol/L HCO₃^- group.It could be concluded that the growth of C.pyrenoidosa 820 was suitable under the conditions of low and moderate salinity,double air CO₂ and higher bicarbonate concentration,and the CA activity was induced by low salinity,air CO₂ and 5 mmol/L HCO₃^-.However,the ca mRNA level was higher under high salinity,double air CO₂ level and 1 mmol/LHCO₃^- conditions.

Abstract:After the success of completely controlled propagation in Chinese sturgeon(Acipenser sinensis),it is necessary to find out the possible behavior variation between wild group and second generation.We combined individual test and population test in 3 different experiments:test of substrate color preference,illumination intensity preference and the optimum illumination.The results showed that both 5-month and 7-month juvenile F₂ A.sinensis significantly chose white substrate(95% Confidence interval of preference on white substrate does not contain 50%).5-month juvenile F₂ A.sinensis individuals significantly chose illuminated area(200-250 lx)(P<0.05),while 7-month ones significantly chose transition area(20-50 lx)(P<0.05).Both 5-month and 7-month juvenile F₂ A.sinensis populations preferred transition area(20-50 lx)(P<0.05)in population test.The different choice of illumination intensity preference between individuals and population in 5-month F₂ A.sinensis may be related to ‘signal-adaptation hypothesis' and the optimum illumination range.5-month juvenile F₂ A.sinensis significantly chose illumination area of 45-135 lx(P<0.05); 7-month juvenile F₂ A.sinensis significantly chose illumination area of 23-202 lx(P<0.05).It meant that with the increasing age,F₂ A.sinensis strengthened its adaptability to illumination.From all above,both 5-month and 7-month juvenile F₂ A.sinensis preferred white substrate,and the optimum illumination range was 20-200 lx.Compared with the existing wild juveniles data,their phototaxis has already declined.

Abstract:Coilia nasus long jaw estuarine tapertail anchovy is an important migratory fish in the Yangtze River.Shortjaw grenadier anchovy has long been thought to only live in freshwater,while there is no evidence for whether it experienced an anadromous migration,which has been an ecological puzzle for it is difficult to distinguish by morphological and molecular biology methods.Otolith element fingerprint could specifically and objectively reflect the environment type which fish had lived in,and the element Sr and Ca microchemistry patterns have been always used to replay the environment type which fish has been experienced.Even one sample is used,its experienced environment type could be effectively replayed.To confirm whether there is anadromous long jaw estuarine tapertail anchovy Coilia nasus in the Yangtze River,an electron probe microanalyzer(EPMA)was applied to analyze the element Sr and Ca microchemistry patterns in otoliths for one short jaw grenadier anchovy(XGC-A)and one long jaw grenadier anchovy(XGC-B),which were collected from Jingjiang Section of Yangtze River on April 27,2013.Meanwhile,experimental and computational data were compared with the anadromous estuarine tapertail anchovy Coilia nasus.Results of line transect analysis showed a complex Sr/Ca ratio pattern in XGC-A and XGC-B,including a low ration[(1.59±0.80),(1.55±0.74)]responded to freshwater life,and a high ration[(4.38±1.33),(3.56±0.94)]responded to seawater life,which suggested that both of them had experienced an anadromous migration.All these differences could be well confirmed by the results of X-ray mapping analysis of EPMA.Results of the microchemistry patterns obtained by both the line transect and mapping analyses confirmed objectively,for the first time,the coexistence of anadromous forms of the shorter supramaxilla estuarine tapertail anchovy C.nasus in the Yangtze River.These afore-mentioned microchemistry patterns will provide impotant information not only for the resources evaluation and protection,but also for the farming plan and future guide in C.nasus.This research provides an important basis for further understanding of short jaw grenadier anchovy life history and Coilia classification.

Abstract:Sepia lycidas is a warm-ocean demersal Cephalopoda that inhabits offshore waters at a depth of approximate 15-100 m,and is mainly distributed from the Indian Ocean to the western Pacific,and few research studies have been reported on this species.In order to enrich theoretical knowledge for the artificial breeding of S.lycidas,the fine structure of reproductive system in male and female S.lycidas was observed by anatomical and histological methods.The results showed that the male reproductive system consists of nine parts,i.e.:testis,sperm duct,mucilaginous gland,ejaculatory apparatus gland,middle tunic gland,outer tunic gland,hardening gland,finishing gland,and spermatophoric sac.The sperm duct could be further divided into anterior,middle(ampullae),and posterior part.The mature spermatozoon produced in the testis and transported by the sperm duct,formed sperm masses in the mucilaginous and ejaculatory apparatus gland,then arranged in a new regular in the middle and outer tunic gland,and turned hard in the hardening gland,and formed mature spematophores in the finishing gland.The mature spematophores stored in the spermatophoric sac,and ejaculated outside by batches in the mating seasons.The female reproductive system consists of five parts,i.e.:ovary,oviduct,oviduct gland,a pair of nidamental gland,and a pair of subaltern nidamental gland.Oogenesis is asynchronous,and the oocyte matures by batches,forms a tertiary egg envelope by joint action of the oviduct gland,nidamental gland,and subaltern nidamental gland.The male and female reproduction system of S.lycidas is adapted to its manner of fertilization and spawning.

Abstract:The freshwater crab Sinopotamon henanense is a species commonly found in freshwaters of China.However,the relevant studies on digestive system of S.henanense have not been reported yet.In the present study,morphological and histological observation of digestive system of the freshwater crab S.henanense was performed based on paraffin section technique,H.E.staining method and light microscope technique.The results showed that the digestive system comprises digestive tract and digestive glands.The digestive tract is composed of esophagus,stomach,midgut and hindgut.The digestive gland is hepatopancreas.The stomach of the crab is divided into cardiac stomach and pyloric stomach.There is a gastric mill with calcified teeth,ridges,spines and setae in the cardiac stomach,which is used to grind food.There are several special structures such as combs in the pyloric stomach,which are for food filtration.The results of light microscopy showed that the wall of esophagus,midgut and hindgut is surrounded by mucosal,muscular and connective tissue layers.The ridges in the surface of epithelium mucosa of each segment of the digestive tract wall take the shape of multigrade wrinkles.The muscular layers consist of longitudinal muscle,striated muscle and radiant muscle.Only in the midgut there are typical microvilli.The epithelium of the digestive tract is covered by cuticle except the midgut.There are more developed cilia on the surface of epithelial mucosa of esophagus and hindgut.The hepatopancreas is composed of several ramose hepatic ducts.Each hepatic duct consists of four types of cells:resorptive cells(R cell),blister-like cells(B cell),fibrillar cells(F cell)and embryonic cells(E cell).The relationship between the tissues and functions of the digestive system were discussed.These results will provide the basic data for the study of digestion physiology of freshwater crabs.

Abstract:The aim of this paper is to investigate the toxic effects of Pb²⁺ on the histopathological changes of gill and hepatopancreas in Tegillarca granosa exposed to four concentrations of Pb²⁺(5,15,45 and 90 μg/L).The experiment lasted for 96 hours.The results are as follows:for the groups of low Pb²⁺ concentrations,the gill isolated from the cartilage tissue,and for the groups of the high concentrations,the epithelia cells dropped,gill cavity swelled,which stored lots of haemocytes; finally the gill broke.The findings of gill ultrastructure showed that the number of secondary lysosome and mitochondrion increased.The influence of Pb²⁺ on the microstructure of hepatic cells only occurred in the groups of high concentrations,turning up some yellow sediment and a loss of dividing lines of the digestive tubules.Its ultrastructure results indicated that with the increasing metal concentrations,there was granular osmiophilic material,and the secondary lysosome increased as well; furthermore,the vacuoles were also present in the cytoplasm and nucleus of hepatic cells,suggesting the cells were irreversibly damaged.Combined with previous studies,we conclude that the histopathological alterations caused by heavy metals are not metal-specific but mainly because of oxidative stress.The antioxidant system is inferred to play a central role in the metal detoxification.

Abstract:In order to determine the transport conditions of large yellow croaker,this paper studied changes of cortisol,glycogen and lactate of large yellow croaker juveniles under the conditions of different density and salinity during transportation.The average body mass of large yellow croaker juveniles was 0.12±0.03 g,three treatments of density(2,4 and 8 g/L)and five treatments of salinity(5,10,15,20 and 25),totally fifteen treatments were set up.After the transportation of 10 h at 16.5℃,mortality and total ammonia nitrogen in water of each group were determined.Results showed that groups with 4 and 8 g/L density(1.33%,2.63%)had significantly higher mortalities than the group of density of 2 g/L(0.77%)(P<0.05),and group of salinity 25(0.44%)had a significantly lower mortality than that at salinity of 10 and 15(1.94%,1.67%)(P<0.05),groups with salinity 10 and15 had a significantly lower mortality than salinity 5 group(2.72%)(P<0.05).Total ammonia nitrogen in water was significantly increased after transportation compared with before(0.15 mg/L)(P<0.05),the total ammonia nitrogen in water were significantly different among different density groups(P<0.05),total ammonia nitrogen content in high density group was higher than that in low density groups; 8 g/L density under the condition of salinity 5 group(1.63 mg/L)had a significantly higher content of total ammonia nitrogen in water salinity of 15(1.38 mg/L),20(1.34 mg/L)and 25(1.31 mg/L)salinity groups,4 g/L density under the condition of 5 salinity group(1.31 mg/L)had a significantly higher content of total ammonia nitrogen in water with the salinity group,2 g/L density under the condition of 5 group(0.83 mg/L)had a significantly higher content of total ammonia nitrogen in water salinity 25 group(0.49 mg/L)(P<0.05).Cortisol levels after transportation were significantly increased compared before transportation(6 476.35 ng/L)(P<0.05); however,cortisol levels showed no significant difference between groups(P>0.05).Glycogen content in each group was significantly reduced compared before transportation(4.37 mg/g prot)(P<0.05),and there was no significant difference between groups(P>0.05).Lactic acid content in each group was significantly higher than that before transportation(0.57 mmol/g prot)(P<0.05),the density had no significant effect on lactic acid levels(P>0.05),for salinity,lactic acid content of salinity 5 group at each density(1.91 mmol/g prot,2.02 mmol/g prot,1.76 mmol/g prot)was significantly higher than salinity 20(1.55 mmol/g prot,1.21 mmol/g prot,1.69 mmol/g prot)and 25 group(1.36 mmol/g prot,1.44 mmol/g prot,1.26 mmol/g prot)(P<0.05),lactic acid content of salinity 10 group(1.77 mmol/g prot,1.83 mmol/g prot,1.60 mmol/g prot)was significantly higher than salinity 25 group(1.36 mmol/g prot,1.44 mmol/g prot,1.26 mmol/g prot)(P<0.05).Statistical analysis showed high transport density and lower salinity can aggravate the stress responses of large yellow croaker juveniles,suggesting that in the conditions of transportation,and with specifications of large yellow croaker larvae around 0.1 g,the transportation requirements should not be higher than 8 g/L in density,and lower than 5 of salinity.

Abstract:The present study explored the Asterias amurensis(4-8 cm)selective feeding on Ruditapes philippinarum(20-40 mm)at different temperatures(5,10,15,20,25℃)in laboratory conditions.The prey profitability,prey size selectivity,total consumption and feeding rate were used to analyse the effects of temperature,predator size and prey size on selective feeding of A.amurensis.Results showed that prey profitability were significantly affected by both the predator size and prey size(P<0.000 1).No significant effects of temperature on the prey profitability were observed(P=1.000 0).According to prey profitability model,four kinds of A.amurensis got maximum when they fed on those preys by 20,23,30 mm and 35 mm respectively.The values were 0.62,0.70,0.83 and 0.94 mg/min.The predictions were in accordance with experimental results.Within temperature range from 5 to 15 degrees and A.amurensis from 5 to 8 cm,the prey consumption increased as the temperature went up,and reached the maximum consumption at 15℃,which was the optimal temperature for A.amurensis.The values were 0.37,0.45 and 0.54 g/d.The prey consumption decreased with the increase of temperature when higher than 15℃.Significantly higher feeding rate was observed by day than at night.It's concluded that in May and June,the temperature of Qingdao was the suitable for the reproduction of R.philippinarum and the most suitable for A.amurensis's feeding and growth.Therefore,the prevention and clearing of starfish should be reinforced.

Abstract:Sea ranching has become one of important ways to mariculture sea cucumber Apostichopus japonicas.As economic deposit feeder species,the sea cucumber has shown promise of removing and recycling the organic materials in the sediment and can play an important ecological role in the maricultural ecosystem.In order to understand the feeding eco-physiological characteristics of sea cucumber A.japonicas,feeding behaviors of different sizes of the sea cucumber at different temperature and feed quality conditions were observed.In this paper,the sea cucumbers were divided into 4 experimental groups by the wet weight.The feeds with different organic contents were got by mixing different ratios of kelp powder and sea mud.5 temperature levels,i.e.(5.1±0.4),(10.9±0.7),(12.5±0.6),(14.2±0.7),(16.1±0.6)℃ were set.The results showed that OC and body weight,had significant influence on the ingestion rate of A.japonicas,however,the interaction of OC,WW had no significant influence on it.The relationship between ingestion rate(OIR)and organic content of feed(OC)could be described as OIR=a×OC/(OC+b),where a,b represented OIR_max,half-saturation constant,respectively.Moreover,the relationship between OIR and water temperature(T)could be described as OIR=c×T²+d×T+e,c=-(0.007 5-0.016 4),d=0.298-0.769,e=-(0.742-1.977).Water temperature(T),wet weight(WW)had a significant influence on feeding behavior of A.japonicas.The interaction also had a significant influence on OIR,but not on AE.In addition,stepwise regression got the relationship of OIR T,WW or OIR OC,WW as follows:OIR=12.55×WW^-0.361+7.92×OC/(OC+4.373)-4.70 or OIR=2.2×WW^-0.384+0.033×WW^-0.384 ×T²+0.077×T respectively.The covariance analysis results showed that the correlation coefficient of the equations reached a significant level.The results suggested that water temperature and food quality were the key factors affecting the feeding ability of the sea cucumber.Through this experiment,we got the necessary parameters for capacity assessment model,such as maximum feeding rate and half-saturation constant of feeding,which will further help to set up the carrying capacity model of sea cucumber farming.

Abstract:In order to evaluate the effect of saponin,extracted from Quillaja saponaria,on non-specific immunity of turbot Scophthalmus maximus,fish was immersed in seawater containing saponin at concentration of 0,15 and 35 mg/L respectively for 1 h.No-specific immune parameters including leukocytes phagocytic activity,ACH50 and total protein of serum,activiies of lysozyme,antibacterial and AKP in serum and skin mucus were analyzed 6,12,24,48 and 72 h after the treatment.The results show that the leukocyte phagocytic activity in the lower concentration group(15 mg/L)at 12 h and in the higher concentration group(35 mg/L)at 24 h was significantly higher than that in the control group(P<0.05).ACH50 in two treatment groups at each testing time were significantly higher than that in control group except the ACH50 in the lower concentration group at 12 h and 24 h(P<0.05).The highest lysozyme activities in serum appeared in the lower concentration group at 6 h,but no ACH50 could be detected in skin mucus.Antibacterial activity in each group changed with time,but it was improved obviously in the two treatment groups at 6 h and 12 h after the immersion,also no difference between the higher and lower saponin groups(P>0.05).Antibacterial activity in serum was too low to be detected.AKP activity of serum in two treatment groups was significantly higher than that in the control at 6 and 12 h respectively(P<0.05),furthermore,obvious differences were found between the two treatment groups.AKP activity of skin mucus in two treatment groups was significantly higher than that in the control at 12 h(P<0.05),but no differences were found between the two treatment groups(P>0.05).Serum total protein in higher concentration group reached the highest value at 6 h,then came to the same level with low concentration group and control group at 12 h.From 24 to 72 h,serum total protein in higher concentration group was remarkably higher than that in the lower concentration and control group.The results indicate that saponin could enhance the non-specific immunity of turbot.

Abstract:To know the microbiome composition and the relationship among Coilia nasus and living area,the preliminary analysis of the bacterial community structure in the water environment,gill,stomach and intestine of Coilia nasus from fishponds,including intestinal wall and intestinal contents based on 16S rDNA PCR-DGGE figure using a culture independent approach.Results indicated that bacterial community structure could be analyzed by PCR-DGGE,The DGGE fingerprint showed respectively 27,9,13,19,18 obvious different Signal strength bands in the samples of water environment,gill,stomach,intestinal wall and intestinal contents of Coilia nasus,meanwhile,the Shannon diversity index of which respectively were 3.037,1.883,2.193,2.825,2.683,these might reflect the existence of rich bacteria species.The clustering analysis to the DGGE fingerprint displayed that no significant differences between groups of Repeating sample,the similarity of which above 95%; The sample of gill and stomach of Coilia nasus get together for a branch,the bacteria structure similarity of which was 77% and that in the intestinal wall and intestinal contents of Coilia nasus was 38%.42 DGGE bands were all successfully re-amplified,cloned,sequenced and aligned with BLAST,including Proteobacteria,Actinobacteria,Firmicutes,Tenericutes,Bacteroidetes Cyanobacteria,Fusobacteria and some unclassified bacteria.These comparison analyses reveal that the great amount of bacterial community in Coilia nasus derived from the culture water.DGGE technique could be used to analyze the bacterial genetic diversity and clarify the predominant bacterial community of Coilia nasus from ponds and its environment.This research has contributed to the development and utilization of probiotics and disease control.

Abstract:Aeromonas are known to cause several diseases in turtles.Antimicrobial agents,such as fluoroquinolones,are used to prevent and curtail bacterial infections.However,prolonged abuse of antimicrobials agents could result in the selection of fluoroquinolone-resistant Aeromonas.Quinolone resistance is due principally to chromosomal mutations or efflux pump.Mutations in the quinolone resistance-determining regions(QRDRs)of the gyrA and parC genes have been shown to be related to quinolone resistance in Aeromonas spp.Plasmid-mediated quinolone resistance(PMQR)determinants(qnrA,qnrB,qnrS and aac(6')-Ib-cr)have been identified exclusively in Enterobacteriaceae,but have very rarely been identified in Aeromonas.In order to determine antimicrobial susceptibility,the relationship of PMQR,QRDR and resistance profiles in clinical isolates of Aeromonas from turtles in Guangdong province,67 isolates were collected from diseased turtles in 1996-2013.All the isolates were tested for resistance to 23 antimicrobial agents by K-B agar disc diffusion method.The PMQR genes qnrA,qnrB,qnrS,qepA and aac(6')-Ib-cr in all these strains were screened by PCR.Then,mutations in QRDR of the gyrA and parC genes and the plasmids were detected in the PMQR positive strains.All the 67 strains were highly resistant to ampicillin,cephalothin and sulfonamides,the resistance rates of which were 100%,92.54% and 83.58%,respectively;it showed medium resistance to quinolones,whose rates were 19.40%-64.18%; the isolates were more susceptible to imipenem,nitrofurantoin,amikacin and cefotaxime,with the resistance rates below 10%.79.10%(53/67)strains showed multiple-resistance to at least three classes of agents.Of these 67 Aeromonas isolates,19.40%(13/67)harbored PMQR genes.PCR and DNA sequence results showed that 8.96%,5.97% and 7.46% were positive for genes qnrS1,qnrS2 and aac(6')-Ib-cr,respectively,and two strains carried both qnrS2 and aac(6')-Ib-cr.All the 13 PMQR positive strains carried 1-4 plasmids,the sizes of which were between 0.8 kb to 15 kb.Among the 13 isolates with PMQR genes,6 strains showed mutations in both gyrA and parC genes,3 strains carried point mutation in gyrA gene,and no mutations of both genes were found in 4 strains.These results indicated that Aeromonas isolated from turtles in Guangdong were of high level multiple-resistance to widely used drugs.The existence of PMQR genes implied a more widespread dissemination of resistance to quinolones in aquaculture,and this should attract more attention.

Abstract:In the present research,the effects of temperature and illumination intensity in liquid preservation as well as the water content of the beads in encapsulation cryopreservation on the preservation of the filaments of S.lomentaria were studied,mainly to find out some appropriate techniques and the optimal situations to realize the effective preservation of germplasm of S.lomentaria.The filaments of S.lomentaria were preserved under various temperature and illumination intensity in the incubator for 60 days in liquid preservation.In encapsulation cryopreservation,filaments of S.lomentaria were stored in -20℃ refrigerator for 30 days after being encapsulated into the beads and dehydrated with silica gel.The experimental results showed that:(1)In liquid preservation,temperature was not the key factor on the preservation of the filaments of S.lomentaria,and the filaments of S.lomentaria could achieve long-term preservation under the condition of 5.4 μmol/(m²·s),6-18℃;(2)The illumination intensity had a significant impact on the liquid preservation of the filaments of S.lomentaria,any illumination intensity higher than 16.2 μmol/(m²·s)was not conducive to the preservation of the germplasm,5.4 μmol/(m²·s)was the most helpful condition;(3)After being preserved at 6-12℃,and 5.4 μmol/(m²·s)for 60 days,the cells of the filaments of S.lomentaria were still in good condition and the survival rates were higher than 97%;(4)The survival rates of the filaments of S.lomentaria after encapsulation cryopreservation were reduced whether the water content of the beads was too high or too low,and 15% was the optimal water content at which the survival rate of the filaments of S.lomentaria preserved for one month could still be higher than 50%.The research demonstrated that,in appropriate situations,filaments of S.lomentaria could be successfully preserved both by the methods of liquid preservation and encapsulation cryopreservation.

Abstract:The resource of Antarctic krill(Euphausia superba)is very abundant.But the content of fluorine in shrimp is very high and is a potential threat to the safety of the consumer.The excessive content of fluorine in Antarctic krill has become the bottleneck for its further utilization.To study the change of content of fluorine in different parts of Antarctic krill,the fluorine-selective electrode method was used to determine the content of fluorine.The results show the content of fluorine in different parts of Antarctic krill has obvious difference,the content of fluorine in shrimp shell is 538.67 mg/kg,shrimp head has 395.20 mg/kg,shrimp meat has 50.33 mg/kg and its content is about 10 percent of shrimp shell.The content of fluorine in the same parts of large Antarctic krill(longer than 45 mm),middle Antarctic krill(between 35 and 45 mm)and small Antarctic krill(shorter than 35 mm)have no obvious difference.The content of fluorine in shrimp,shrimp head and shrimp shell was decreasing when Antarctic krill was preserved at 4℃,but within 4 hours the content of fluorine in shrimp meat was increased,reaching a maximum at 59.67 mg/kg,then decreased.Antarctic krill were heated at 70℃ and boiling for 10 minutes,the content of fluorine in shrimp,shrimp shell and shrimp head had no obvious difference.Antarctic krill were preserved for 1 and 4 h at room temperature after heat treatment,the content of fluorine in shrimp,shrimp head and shrimp shell had little change.The content of fluorine in shrimp meat after heat treatment was higher than fresh shrimp meat.The contents of fluorine in shrimp meat of frozen and frozen cooked Antarctic krill were both higher than that of fresh Antarctic krill,and frozen cooked shrimp fluorine content of Antarctic krill is lower about 23 percent than the fluorine content in the frozen Antarctic krill.The experimental results show that proper processing in the ship can significantly reduce the content of fluorine in shrimp meat.This research will provide theoretical support to reduce the fluorine content in Antarctic krill and promote the development and utilization of the Antarctic krill.

Abstract:To evaluate the N-acylated-L-homoserine lactones(AHLs)profiling of quorum sensing signal molecules of pathogen and spoilage bacteria from aquatic product,the technique of LC-MS/MS detecting simultaneously the AHLs was developed,compared with biosensor method.The results showed that Aeromonas hydrophila A2 and two strains of Pseudomonas aeruginosa secreted AHLs by biosensors Chromobacterium violacceum CV026 and Agrobacterium tumefaciens A136.The LC-MS/MS technique could be applied to qualitative and quantitative analysis of 11 kinds of AHLs.High levels of AHLs with 3-oxo-C₁₂-HSL and C₄-HSL being the most prominent were produced by P.aeruginosa and A.hydrophila,respectively.Low content of AHLs with C₄-HSL was secreted by S.putrefaciens XH4,whereas no AHLs were detected in Salmonella ATCC 14028-3,Escherichia.coli O157:H7 and three species of Vibro.The production of AHLs of P.aeruginosa ATCC 9027 increased with the growth of bacteria,and the highest level of AHLs was observed after 12 h culture.Thus,the LC-MS/MS methodology can provide comprehensive profiles and concentration of AHLs in single sample,with high accuracy and sensitivity.Furthermore,P.aeruginosa and A.hydrophila produced the higher level of AHLs of quorum sensing signal molecules among 11 strains of pathogen and spoilage bacteria from aquatic product,which will provide the good foundation to explore the mechanism and control of these bacteria.

Abstract:To prevent and control the invasion of non-indigenous species,meanwhile,to protect ecological security and biological resources in Zhoushan sea area,we set up 11 sampling sites to investigate the biodiversity of intertidal organisms in 2010 and 2012,respectively.The study collected a species of barnacle in Yangshan deep water port for the first time in 2010.This species has a rhombic aperture,porominent joint ridge and membranous basis.We could accurately identify the species as Chthamalus challengeri by its four teeth of mandible,legible incision of maxillule and quadrate sheet cirrus.The genetic distances and population genetic structure of C.challengeri were investigated using mitochondrial cytochrome C oxidase subunit Ⅰ(COⅠ)gene sequences.The population genetic distance of samples collected from Zhoushan sea area and COⅠ sequences downloaded from NCBI is 0.994%,which shows a great possibility for the new species from Zhoushan sea area to be the species of C.challengeri.The result of Neighbor-Joining tree showed the same verdict with population genetic distance result,which provides corroborative evidence for the identification of the new species from Zhoushan sea area.The results of ecology survey showed that C.challeneri were collected in minority area of Zhoushan from Yangshan deep water port,Shengsi,Qushan,Daishan and Zhujiajian,and the density of it ranged from(6±2)to(28±11)ind./m².In 2012,we could collect it from all the sampling sites of Zhoushan archipelago,the densities for the 6 sampling sites which had collected C.challengeri in 2010 ranged from(55±8)to(39 533±6 243)ind./m² in 2012.The densities of other 5 sampling sites ranged from(16±4)to(20 000±4 000)ind./m².This study elaborates the research status of C.challangeri as a non-indigenous species in Zhoushan sea area from various angles of its biological characteristics,population historic distribution area,introduced geschichte and spread status.