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1.
White spot syndrome virus (WSSV) is an important viral pathogen that infects farmed penaeid shrimp, and the threat of Vibrio parahaemolyticus infection to shrimp farming has become increasingly severe. Viral and bacterial cross or superimposed infections may induce higher shrimp mortality. We used a feeding method to infect Litopenaeus vannamei with WSSV and then injected a low dose of V. parahaemolyticus (WSSV+Vp), or we first infected L. vannamei with a low-dose injection of V. parahaemolyticus and then fed the shrimp WSSV to achieve viral infection (Vp+WSSV). The eff ect of V. parahaemolyticus and WSSV co-infection on survival of L. vannamei was evaluated by comparing cumulative mortality rates between experimental and control groups. We also spread L. vannamei hemolymph on thiosulfate citrate bile salt sucrose agar plates to determine the number of Vibrio, and the WSSV copy number in L. vannamei gills was determined using an absolute quantitative polymerase chain reaction (PCR) method. LvMyD88 and Lvakt gene expression levels were detected in gills of L. vannamei by real-time PCR to determine the cause of the diff erent mortality rates. Our results show that (1) the cumulative mortality rate of L. vannamei in the WSSV+Vp group reached 100% on day 10 after WSSV infection, whereas the cumulative mortality rate of L. vannamei in the Vp+WSSV group and the WSSV-alone control group approached 100% on days 11 and 13 of infection; (2) the number of Vibrio in the L. vannamei group infected with V. parahaemolyticus alone declined gradually, whereas the other groups showed significant increases in the numbers of Vibrio (P<0.05); (3) the WSSV copy numbers in the gills of the WSSV+Vp, Vp+WSSV, and the WSSV-alone groups increased from 105 to 107 /mg tissue 72, 96, and 144 h after infection, respectively. These results suggest that V. parahaemolyticus infection accelerated proliferation of WSSV in L. vannamei and vice versa. The combined accelerated proliferation of both V. parahaemolyticus and WSSV led to massive death of L. vannamei.  相似文献   

2.
To elucidate the molecular response of shrimp hepatopancreas to white spot syndrome virus (WSSV) infection, microarray was applied to investigate the differentially expressed genes in the hepatopancreas of ‘Huanghai No. 2’ (Fenneropenaeus chinensis). A total of 59137 unigenes were designed onto a custom-made 60K Agilent chip. After infection, the gene expression profiles in the hepatopancreas of the shrimp with a lower viral load at early (48–96 h), peak (168–192 h) and late (264–288 h) infection phases were analyzed. Of 18704 differentially expressed genes, 6412 were annotated. In total, 5453 differentially expressed genes (1916 annotated) expressed at all three phases, and most of the annotated were either up- or down-regulated continuously. These genes function diversely in, for example, immune response, cytoskeletal system, signal transduction, stress resistance, protein synthesis and processing, metabolism among others. Some of the immune-related genes, including antilipopolysaccharide factor, Kazal-type proteinase inhibitor, C-type lectin and serine protease encoding genes, were up-regulated after WSSV infection. These genes have been reported to be involved in the anti-WSSV responses. The expression of genes related to the cytoskeletal system, including β-actin and myosin but without tubulin genes, were down-regulated after WSSV infection. Astakine was found for the first time in the WSSV-infected F. chinensis. To further confirm the expression of differentially expressed genes, quantitative real-time PCR was performed to test the expression of eight randomly selected genes and verified the reliability and accuracy of the microarray expression analysis. The data will provide valuable information to understanding the immune mechanism of shrimp’s response to WSSV.  相似文献   

3.
The pattern recognition proteins (PRPs) play a major role in immune response of crustacean to resist pathogens. In the present study, as one of PRPs, lipopolysaccharide and β-1, 3-glucan binding protein (LGBP) gene in the ridge tail white prawn (Exopalaemon carinicauda) (EcLGBP) was isolated. The full-length cDNA of EcLGBP was 1338 bp, encoding a polypeptide of 366 amino acid residules. The deduced amino acid sequence of EcLGBP shared high similarities with LGBP and BGBP from other crustaceans. Some conservative domains were predicted in EcLGBP sequence. EcLGBP constitutively expressed in most tissues at different levels, and the highest expression was observed in hepatopancreas. With infection time, the cumulative mortality increased gradually followed by the proliferation of Vibrio parahaemolyticus and white spot syndrome virus (WSSV). The expression of EcLGBP in response to V. parahaemolyticus infection was up-regulated in hemocytes and hepatopancreas, and the up-regulation in hepatopancreas was earlier than that in hemocytes. EcLGBP expression after WSSV infection increased at 3 h, then significantly decreased in both hemocytes and hepatopancreas. The results indicated that EcLGBP was involved in the immune defense against bacterial and viral infections.  相似文献   

4.
5.
White spot syndrome virus(WSSV) is an important viral pathogen that infects farmed penaeid shrimp, and the threat of Vibrio parahaemolyticus infection to shrimp farming has become increasingly severe. Viral and bacterial cross or superimposed infections may induce higher shrimp mortality. We used a feeding method to infect L itopenaeus vannamei with WSSV and then injected a low dose of V. parahaemolyticus(WSSV+Vp), or we fi rst infected L. vannamei with a low-dose injection of V. parahaemolyticus and then fed the shrimp WSSV to achieve viral infection(Vp+WSSV). The effect of V. parahaemolyticus and WSSV co-infection on survival of L. vannamei was evaluated by comparing cumulative mortality rates between experimental and control groups. We also spread L. vannamei hemolymph on thiosulfate citrate bile salt sucrose agar plates to determine the number of V ibrio, and the WSSV copy number in L. vannamei gills was determined using an absolute quantitative polymerase chain reaction(PCR) method. L v My D88 and Lvakt gene expression levels were detected in gills of L. vannamei by real-time PCR to determine the cause of the different mortality rates. Our results show that(1) the cumulative mortality rate of L. vannamei in the WSSV+Vp group reached 100% on day 10 after WSSV infection, whereas the cumulative mortality rate of L. vannamei in the Vp+WSSV group and the WSSV-alone control group approached 100% on days 11 and 13 of infection;(2) the number of Vibrio in the L. vannamei group infected with V. parahaemolyticus alone declined gradually, whereas the other groups showed signifi cant increases in the numbers of Vibrio( P 0.05);(3) the WSSV copy numbers in the gills of the WSSV+Vp, Vp+WSSV, and the WSSV-alone groups increased from 10 5 to 10 7 /mg tissue 72, 96, and 144 h after infection, respectively. These results suggest that V. parahaemolyticus infection accelerated proliferation of WSSV in L. vannamei and vice versa. The combined accelerated proliferation of both V. parahaemolyticus and WSSV led to massive death of L. vannamei.  相似文献   

6.
Flavobacterium columnare causes columnaris disease in freshwater fish. In the present study, the antigenic regions of five outer membrane proteins (OMPs), including zinc metalloprotease, prolyl oligopeptidase, thermolysin, collagenase and chondroitin AC lyase, were bioinformatically analyzed, fused together, and then expressed as a recombinant fusion protein in Escherichia coli. The expressed protein of 95.6 kDa, as estimated by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was consistent with the molecular weight deduced from the amino acid sequence. The purified recombinant protein was used to vaccinate the grass carp, Ctenopharyngodon idella. Following vaccination of the fish their IgM antibody levels were examined, as was the expression of IgM, IgD and IgZ immunoglobulin genes and other genes such as MHC Iα and MHC IIβ, which are also involved in adaptive immunity. Interleukin genes (IL), including IL-1β, IL-8 and IL-10, and type I and type II interferon (IFN) genes were also examined. At 3 and 4 weeks post-vaccination (wpv), significant increases in IgM antibody levels were observed in the fish vaccinated with the recombinant fusion protein, and an increase in the expression levels of IgM, IgD and IgZ genes was also detected following the vaccinations, thus indicating that an adaptive immune response was induced by the vaccinations. Early increases in the expression levels of IL and IFN genes were also observed in the vaccinated fish. At four wpv, the fish were challenged with F. columnare, and the vaccinated fish showed a good level of protection against this pathogen, with 39% relative percent survival (RPS) compared with the control group. It can be concluded, therefore, that the five OMPs, in the form of a recombinant fusion protein vaccine, induced an immune response in fish and protection against F. columnare.  相似文献   

7.
White spot syndrome virus (WSSV)-resistant molecular markers were screened from the selectively bred new variety ‘Huanghai No. 2’ of Fenneropenaeus chinensis using unlabeled-probe high-resolution melting (HRM) technique. After the artificial infection with WSSV, the first 96 dead shrimps and the last 96 surviving shrimps were collected, representing WSSV-susceptible and -resistant populations, respectively. The genotypes at well-developed 39 single nucleotide polymorphisms (SNPs) loci were obtained. As revealed in the Chi-square test, 3 SNPs, genotype A/A of contig C364-89AT, genotype A/A of C2635-527CA and genotype C/T of contig C12355-592CT, were positively correlated with disease-resistance traits. Other 2 SNPs, genotype G/G of contig C283-145AG and genotype C/C of contig C12355-592CT, were negatively correlated. Moreover, analysis with BlastX program for disease-resistant SNPs indicated that 3 contigs, Contig283, Contig364 and Contig12355, matched to the functional genes of effector caspase of Penaeus monodon, peptide transporter family 1-like protein, and 40S ribosomal protein S2 of Perca flavescens with high sequence similarity. The results will be helpful to provide theoretical and technical supports for molecular marker-assisted selective breeding of F. chinensis.  相似文献   

8.
9.
The pathological changes of hemocytes in the haemolymph and hepatopancreas were examined in experimentally and naturally WSSV (white spot syndrome virus) infected Fenneropenaeus chinensis. The results showed that the pathological manifestations of hemocytes were similar among moribund shrimps infected via injection, feeding and by nature. Firstly, the total hemocyte counts (THCs) in WSSV-infected shrimp were significantly lower than those in healthy shrimp. Secondly, necrotic, broken and disintegrated cells were often observed, and a typical hematolysis was present in the haemolymph smear of WSSV-infected shrimp. Thirdly, necrosis and typical apoptosis of hemocytes were detected with TEM in the peripheral haemolymph of WSSV-infected shrimp. Hyalinocytes and semi-granulocytes with masses of WSSVs in their nuclei often appeared, whereas no granular hemocytes with WSSV were found in the hepatopancreas of moribund infected shrimps. All our results supported that hemocytes were the main target cells of WSSV, and hyalinocytes and semigranular hemocytes seemed to be more favorable for WSSV infection in F. chinensis.  相似文献   

10.
The pathological changes of hemocytes in the haemolymph and hepatopancreas were examined in experimentally and naturally WSSV (white spot syndrome virus) infected Fenneropenaeus chinensis. The results showed that the pathological manifesta- tions of hemocytes were similar among moribund shrimps infected via injection, feeding and by nature. Firstly, the total hemocyte counts (THCs) in WSSV-infected shrimp were significantly lower than those in healthy shrimp. Secondly, necrotic, broken and dis- integrated cells were often observed, and a typical hematolysis was present in the haemolymph smear of WSSV-infected shrimp. Thirdly, necrosis and typical apoptosis of hemocytes were detected with TEM in the peripheral haemolymph of WSSV-infected shrimp. Hyalinocytes and semi-granulocytes with masses of WSSVs in their nuclei often appeared, whereas no granular bemocytes with WSSV were found in the hepatopancreas of moribund infected shrimps. All our results supported that hemocytes were the main target cells of WSSV, and hyalinocytes and semigranular hemocytes seemed to be more favorable for WSSV infection in F. chinensis.  相似文献   

11.
Two-dimensional electrophoresis(2-DE) of protein extracted and purified from Alexandrium sp. LC3 was conducted. In the SDS-PAGE study, the relative molecular weights of the proteins were mainly in the range of 14 kDa?31 kDa and 43 kDa?66 kDa, and more proteins were detected between 14 kDa and 31 kDa. With the improved protein preparation, the two-dimensional electrophoresis patterns indicated that the relative molecular weights of the proteins were between 14 kDa and 100 kDa, and most of them ranged from 14 kDa to 31 kDa. This was consistent with the result of the SDS-PAGE analysis. The isoelectric points were found to lie between 3.0 and 8.0, and most of them were in the range of 3.0?6.0. Better separation effect was acquired with pre-prepared immobilized gradient (IPG) strip (pH 3?5.6), and about 320 protein spots could be visualized on the 2-DE map by staining. Within pH 3?10 and pH 3?5.6 strips, the protein samples of Alexandrium sp. LC3 could be separated well.  相似文献   

12.
A small amount of heavy metal binding protein,identified by BioRad Protein Assay,has been iso-lated from the adult brine shrimp,Artemia franciscanus.This protein has an apparent molecular weight be-tween 6000 to 9000 dalton.a UV absorption peak at 260 instead of 280 nm like most proteins;andhas high affinity towards binding with radioactive labeled ~(109)Cd.These characteristics are similarto that of metallothioneins reported for many vertebrate and invertebrate,marine and terrestrialanimals.After the brine shrimp is exposed to a small amount of Cd~(2+)for 24 h,a large amount ofmetallothionein can be isolated,showing the inducibility of this detoxifying protein in the adult Artemiain a short period of time.  相似文献   

13.
14.
A small amount of heavy metal binding protein, identified by BioRad Protein Assay, has been isolated from the adult brine shrimp,Artemia franciscanus. This protein has an apparent molecular weight between 6000 to 9000 dalton. a UV absorption peak at 260 instead of 280 nm like most proteins; and has high affinity towards binding with radioactive labeled109Cd. These characteristics are similar to that of metallothioneins reported for many vertebrate and invertebrate, marine and terrestrial animals. After the brine shrimp is exposed to a small amount of Cd2+ for 24 h, a large amount of metallothionein can be isolated, showing the inducibility of this detoxifying protein in the adultArtemia in a short period of time.  相似文献   

15.
16.
The present study was conducted to evaluate the feasibility of replacing fish meal (FM) with bioactive peptides (BPs) in diet of white shrimp (Litopenaeus vannamei). The changes in growth performance, body composition, non-specific immunity, and water quality were examined after the shrimp were fed four diets, in which 0% (control), 33.3%, 66.7% and 100% of FM was replaced by BPs, respectively. The groups were designated as Con, 1/3BPs, 2/3BPs, and 3/3BPs. A total of 720 shrimp with an initial body weight of 1.46 ± 0.78 g were fed the experimental diets for 56 days. The results revealed that: 1) the weight gain rate (WGR) in 1/3BPs, 2/3BPs, and 3/3BPs was significantly higher than that in Con (P < 0.05), while no significant difference was found on survival rate and feed conversion ratio (FCR); 2) the whole-body crude protein (CP) and crude lipids (CL) were significantly different among groups, while there was no significant difference between crude ash and phosphorus contents; 3) the levels of acid phosphatase (ACP), lysozyme (LZM), superoxide dismutase (SOD), phenol oxidase (PO) and bactericidal activity increased significantly with the inclusion of BPs; 4) in terms of water quality, no significant difference was found in pH and dissolved oxygen among diets during the whole experimental period. Moreover, even though nitrite and ammonium levels tended to increase with time, there was no significant difference among groups. The results indicated that BPs is an applicable alternative of protein source, which can substitute FM in the diets of L. vannamei; it is able to effectively promote growth performance and improve immunity. Moreover, BPs in the diets had no negative impact on water quality.  相似文献   

17.
INTRODUCTIONWhiteSpotSyndromeVirus (WSSV)inPenaeuschinensisisthecausativeagentofaverysevereepizooticdiseasewhich,startingfrom 1 993 ,hadresultedinmorethan 80 %mortalitythroughoutshrimpculturefarmsinChina (Zhanetal.,1 995;1 998) .Now ,fiveyearslater,thevirusdiseaseissti…  相似文献   

18.
Monoculture of sea cucumber (pond S) and polyculture of shrimp with sea cucumber (pond SS) were established to evaluate the effect of shrimp on the environmental conditions of sea cucumber farming pond. Contributions of sediment organic matter (SOM2) resuspended from benthic sediment and the suspended particulate organic matter (SPOM) deposited from the water column to the precipitated organic matter (SOM1) collected with sediment traps were estimated with carbon stable isotope analysis. The results showed that the levels of SPOM and SOM2 in pond SS significantly decreased in comparison with those in pond S at the end of experiment (P < 0.05), indicating that co-culturing shrimp in sea cucumber farming pond could purify the farming water. Carbon stable isotope analysis showed that the proportion of SOM2 in SOM1 in pond SS (84.97% ± 0.38%) was significantly lower than that in pond S (95.20% ± 0.30%) (P < 0.05), suggesting that the resuspension of organic matter from benthic sediment into overlying water was reduced in polyculture pond. In contrast, the proportion of SPOM in SOM1 in pond SS (15.03% ± 0.38%) was significantly higher than that in pond S (4.80% ± 0.30%) (P < 0.05), indicating that the sedimentation of SPOM from water column was enhanced in pond SS owing to the biodeposition effect of shrimp.  相似文献   

19.
Using net enclosures in an earthen pond, we established three culture treatments with the sea cucumber Apostichopus japonicus and the Chinese white shrimp Fenneropenaeus chinensis: monoculture of sea cucumbers (C), monoculture of shrimp (S), and co-culture of the two species (CS). We measured levels of suspended particulate matter in the water column; total organic matter, total organic carbon, total nitrogen, and carbon/nitrogen ratios in both settling particles and the sediment; and chlorophyll a levels in the sediment. We then compared these variables between the three treatments. We also examined growth, survival, and yield of the two species in the different treatments. From June to September, the mean monthly suspended particulate matter sedimentation rates in the CS and S treatments were significantly (P<0.05) greater than those in the C treatment. From August to November, the mean monthly total organic matter, total organic carbon, total nitrogen, and chlorophyll a contents in the sediment in the CS and S treatments were significantly ( P <0.05) greater than those in the C treatment. Final wet weight, specific growth rate, survival rate, and total yield of sea cucumbers in co-culture were all significantly greater than those of sea cucumbers in monoculture. There were no significant differences among any of these variables for shrimp reared in the two systems. The bioturbation of the sediment and fecal production of the shrimp likely supplied natural food for the sea cucumbers. Co-culture of the two species is a viable option for increasing yield per unit area, maximizing use of the water body, and diversifying crop production.  相似文献   

20.
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