Pathogenicity of white-spot syndrome virus in Macrobrachium nipponensis via different infection routes / 生物工程学报

Macrobrachium nipponensis is delicious and has high economic value, but its susceptibility to white-spot syndrome virus (WSSV) is unknown. Susceptibility, morbidity, and multiplication of WSSV in M. nipponense were studied by epidemiological survey, infection experiment and qPCR. M. nipponense was the natural host of WSSV, and the natural carrying rate was about 8.33%. M. nipponense could be infected with WSSV via oral administration, muscle injection and immersion, and the cumulative infection rate of 10 d exposure was 100%, and the cumulative mortality rates were 100%, 75% and 0%, respectively. The infection of WSSV is fast by muscle injection. The virus content after 5 day's injection is 1 000 times higher than that of the first day of infection, and the mortality rate reached 100% after 8 days. The median lethal dose (LD₅₀) measured as the mortality of infected M. nipponense via injection indicated the LD₅₀ in the concentration of WSSV of 2.71×10⁵ virions/μL. In shrimp farming, M. nipponense can be infected by ingesting WSSV infected shrimp or dead shrimp, and also by soaking in WSSV-containing water and thus become a vector, consequently affecting the spread and pathogenicity of WSSV.

Molecular Docking Analyses of Cynodon Dactylon Derived Phytochemicals Against White Spot Syndrome VIRUS (WSSV) Structural Protein VP26.

White spot disease is a major infectious disease of penaeid shrimps caused by the white spot syndrome virus (WSSV). The viral structural proteins are responsible for binding virus to the cellular membranes of the host that is being systematically infected. An In silico attempt was made to identify the potential drug to inhibit the WSSV spread of diseases. For that an effort, was made to deduce the antiviral potentiality of Cynodon dactylon derived phytochemicals with docking technique. To stimulate the structure based drug design the, 3D structure of the VP26 (PDB-ID: 2EDM), a tegument protein thought to be involved in the entry of WSSV nucleocapsid into the host nucleus, is retrieved from PDB database and docking studies are carried out with the sketched phytochemical structures using GOLD software. Among the phytochemicals screened, luteolin and apigenin shows the best binding affinity with binding energies of 42.51 and 38.92 K.cal/mol exhibiting the potential to block VP26 (2EDM) protein of WSSV. This study will be helpful in developing novel antiviral drugs from plant sources against aquatic important pathogens.

Screening, isolation and optimization of anti-white spot syndrome virus drug derived from terrestrial plants

<p><b>OBJECTIVE</b>To screen, isolate and optimize anti-white spot syndrome virus (WSSV) drug derived from various terrestrial plants and to evaluate the efficacy of the same in host-pathogen interaction model.</p><p><b>METHODS</b>Thirty plants were subjected to Soxhlet extraction using water, ethanol, methanol and hexane as solvents. The 120 plant isolates thus obtained were screened for their in vivo anti-WSSV property in Litopenaeus vannamei. The best anti-WSSV plant isolate, TP22C was isolated and further analyzed. The drug was optimized at various concentrations. Viral and immune genes were analysed using reverse transcriptase PCR to confirm the potency of the drug.</p><p><b>RESULTS</b>Seven plant isolates exhibited significant survivability in host. The drug TP22C thus formulated showed 86% survivability in host. The surviving shrimps were nested PCR negative at the end of the 15 d experimentation. The lowest concentration of TP22C required intramuscularly for virucidal property was 10 mg/mL. The oral dosage of 750 mg/kg body weight/day survived at the rate of 86%. Neither VP28 nor ie 1 was expressed in the test samples at 42nd hour and 84th hour post viral infection.</p><p><b>CONCLUSIONS</b>The drug TP22C derived from Momordica charantia is a potent anti-white spot syndrome virus drug.</p>

Screening, isolation and optimization of anti-white spot syndrome virus drug derived from marine plants

<p><b>OBJECTIVE</b>To screen, isolate and optimize anti-white spot syndrome virus (WSSV) drug derived from various marine floral ecosystems and to evaluate the efficacy of the same in host-pathogen interaction model.</p><p><b>METHODS</b>Thirty species of marine plants were subjected to Soxhlet extraction using water, ethanol, methanol and hexane as solvents. The 120 plant isolates thus obtained were screened for their in vivo anti-WSSV property in Litopenaeus vannamei. By means of chemical processes, the purified anti-WSSV plant isolate, MP07X was derived. The drug was optimized at various concentrations. Viral and immune genes were analysed using reverse transcriptase PCR to confirm the potency of the drug.</p><p><b>RESULTS</b>Nine plant isolates exhibited significant survivability in host. The drug MP07X thus formulated showing 85% survivability in host. The surviving shrimps were nested PCR negative at the end of the 15 d experimentation. The lowest concentration of MP07X required intramuscularly for virucidal property was 10 mg/mL. The oral dosage of 1 000 mg/kg body weight/day survived at the rate of 85%. Neither VP28 nor ie 1 was expressed in the test samples at 42nd hour and 84th hour post viral infection.</p><p><b>CONCLUSIONS</b>The drug MP07X derived from Rhizophora mucronata is a potent anti-WSSV drug.</p>

Screening, isolation and optimization of anti-white spot syndrome virus drug derived from terrestrial plants

Objective: To screen, isolate and optimize anti-white spot syndrome virus (WSSV) drug derived from various terrestrial plants and to evaluate the efficacy of the same in host–pathogen interaction model.Methods:Thirty plants were subjected to Soxhlet extraction using water, ethanol, methanol and hexane as solvents. The 120 plant isolates thus obtained were screened for their in vivo anti–WSSV property in Litopenaeus vannamei. The best anti–WSSV plant isolate, TP22C was isolated and further analyzed. The drug was optimized at various concentrations. Viral and immune genes were analysed using reverse transcriptase PCR to confirm the potency of the drug.Results: Seven plant isolates exhibited significant survivability in host. The drug TP22C thus formulated showed 86% survivability in host. The surviving shrimps were nested PCR negative at the end of the 15 d experimentation. The lowest concentration of TP22C required intramuscularly for virucidal property was 10 mg/mL. The oral dosage of 750 mg/kg body weight/day survived at the rate of 86%. Neither VP28 nor ie 1 was expressed in the test samples at 42nd hour and 84th hour post viral infection.Conclusions:The drug TP22C derived from Momordica charantia is a potent anti-white spot syndrome virus drug.

Screening, isolation and optimization of anti-white spot syndrome virus drug derived from marine plants

Objective: To screen, isolate and optimize anti-white spot syndrome virus (WSSV) drug derived from various marine floral ecosystems and to evaluate the efficacy of the same in host–pathogen interaction model.Methods:ethanol, methanol and hexane as solvents. The 120 plant isolates thus obtained were screened for their in vivo anti-WSSV property in Litopenaeus vannamei. By means of chemical processes, the purified anti-WSSV plant isolate, MP07X was derived. The drug was optimized at various concentrations. Viral and immune genes were analysed using reverse transcriptase PCR to confirm the potency of the drug.Results:Thirty species of marine plants were subjected to Soxhlet extraction using water, formulated showing 85% survivability in host. The surviving shrimps were nested PCR negative at the end of the 15 d experimentation. The lowest concentration of MP07X required intramuscularly for virucidal property was 10 mg/mL. The oral dosage of 1000 mg/kg body weight/day survived at the rate of 85%. Neither VP28 nor ie 1 was expressed in the test samples at 42nd hour and 84th hour post viral infection.Conclusions:Nine plant isolates exhibited significant survivability in host. The drug MP07X thus The drug MP07X derived from Rhizophora mucronata is a potent anti-WSSV drug.

Detection of white spot syndrome virus in Brazil using negative staining, immunoelectron microscopy and immunocytochemistry techniques / Detección del virus del síndrome de mancha blanca en el Brasil utilizando inmunomicroscopía e inmunomarcación con partículas de oro coloidal

In this study thirty shrimp samples from commercial marine shrimp (L. vannamei) farms of southern region of Brazil were obtained. Hepatopancreas and shell scrapings fragments collected in these animals were processed by transmission electron microscopy using negative staining (rapid preparation), immunoelectron microscopy and immunocytochemistry (immunolabelling with colloidal gold particles) techniques. On the transmission electron microscopy a great number of white spot virus particles, ovoid or bacilliform-to-ellipsoid, measured 230-290 nm in length and 80-160 nm in diameter with intra-nuclear projections were visualized by the negative staining technique in 27 (90 percent) out of 30 samples examined. Using immunoelectron microscopy technique, the anti-VP 664 serum agllutinated a large number of particles formed by antigen-antibody interaction. In the immunocytochemistry technique, the antigen-antibody reaction was styrongly marked by the particles of colloidal gold over the virus. Notably, this is the first report, to our knowledge, describing use of these microscopy techniques to study Brazilian L. vannamei marine shrimp samples; moreover, this methodology also appears to be a viable complementary tool for diagnosing the presence of the white spot virus within shrimp tissues. Importantly, these are the first photoelectron micrographs of the WSSV in Brazil.

Se obtuvieron para el estudio 30 muestras de camarones marinos comerciales (L. vannamei) de las granjas de la región sur de Brasil. Fueron procesados fragmentos de hepatopáncreas y raspados internos del cefalotórax recogidos en estos animales por microscopía electrónica de transmisión con tinción negativa (preparación rápida), inmunomicroscopía y técnicas de inmunocitoquímica (inmunomarcación con partículas de oro coloidal). En la microscopía electrónica de transmisión de un gran número de partículas de virus de la mancha blanca, ovoide o elipsoidal a baciliformes, medían 230-290 nm de longitud y 80-160 nm de diámetro. En 27 (90 por ciento) de las 30 muestras examinadas intra-nuclear proyecciones se visualizaron mediante la técnica de tinción negativa. Utilizando una técnica de inmunomicroscopía electrónica, el anti-suero VP 664 reunió a un gran número de partículas formadas por la interacción antígeno-anticuerpo. En la técnica de inmunocitoquímica, la reacción antígeno-anticuerpo fue fuertemente reforzada por las partículas de oro coloidal en los virus. En particular, en Brasil este es el primer informe, a nuestro entender, que describe el uso de estas técnicas de microscopía en muestras de camarón marino L. vanamei. Además, esta metodología también parece ser una herramienta complementaria viable para diagnosticar la presencia del virus de la mancha blanca en tejidos de camarón. Es importante destacar que estas son las primeras fotos en microscopia electrónica del WSSV obtenidas en Brasil.

Prevalence of Three Shrimp Viruses in Zhejiang Province in 2008 / 中国病毒学·英文版

White spot syndrome virus(WSSV), Taura syndrome virus(TSV)and Infectious hypodermal and haematopoietic necrosis virus(IHHNV)are three shrimp viruses responsible for major pandemics affecting the shrimp farming industry. Shrimps samples were collected from 12 farms in Zhejiang province, China, in 2008 and analyzed by PCR to determine the prevalence of these viruses. From the 12 sampling locations, 8 farms were positive for WSSV, 8 for IHHNV and 6 for both WSSV and IHHNV. An average percentage of 57.4% of shrimp individuals were infected with WSSV, while 49.2% were infected with IHHNV. A high prevalence of co-infection with WSSV and IHHNV among samples was detected from the following samples: Bingjiang(93.3%), liuao(66.7%), Jianshan(46.7%)and Xianxiang(46.7%). No samples exhibited evidence of infection with TSV in collected samples. This study provides comprehensive information of the prevalence of three shrimp viruses in Zhejiang and may be helpful for disease prevention control in this region.

Characterization and Diagnostic Use of a Monoclonal Antibody for VP28 Envelope Protein of White Spot Syndrome Virus / 中国病毒学·英文版

The gene encoding the VP28 envelope protein of White spot syndrome virus (WSSV)was cloned into expression vector pET-30a and transformed into the Escherichia coli strain BL21.After induction,the recombinant VP28 (rVP28) protein was purified and then used to immunize Balb/c mice for monoclonal antibody (MAb) production.It was observed by immuno-electron microscopy the MAbs specific to rVP28 could recognize native VP28 target epitopes of WSSV and dot-blot analysis was used to detect natural WSSV infection.Competitive PCR showed that the viral level was approximately 104 copies/mg tissue in the dilution of gill homogenate of WSSV-infected crayfish at the detection limit of dot-blot assay.Our results suggest that dot-blot analysis with anti-rVP28 MAb could rapidly and sensitively detect WSSV at the early stages of WSSV infection.

Identification and Characterization of Nuclear Localization Signals within the Nucleocapsid Protein VP15 of White Spot Syndrome Virus / 中国病毒学·英文版

The nucleocapsid protein VP15 of white spot syndrome virus (WSSV) is a basic DNA-binding protein. Three canonical bipartite nuclear localization signals (NLSs), called NLS1 (aa 11-27), NLS2 (aa 33-49) and NLS3 (44-60), have been detected in this protein, using the ScanProsite computer program. To determine the nuclear localization sequence of VP15, the full-length open reading frame, or the sequence of one of the three NLSs, was fused to the green fluorescent protein (GFP) gene, and transiently expressed in insect Sf9 cells. Transfection with full-length VP15 resulted in GFP fluorescence being distributed exclusively in the nucleus. NLS 1 alone could also direct GFP to the nucleus, but less efficiently. Neither of the other two NLSs (NLS2 and 3) was functional when expressed alone, but exhibited similar activity to NLS1 when they were expressed as a fusion peptide. Furthermore, a mutated VP15, in which the two basic amino acids (11RR12) of NLSI were changed to two alanines (11AA12), caused GFP to be localized only in the cytoplasm of Sf9 cells. These results demonstrated that VP15, as a nuclear localization protein, needs cooperation between its three NLSs, and that the two residues (11RR12) of NLS1 play a key role in transporting the protein to the nucleus.

Proteomic Analyses of the Shrimp White Spot Syndrome Virus / 中国病毒学·英文版

White spot syndrome virus (WSSV), a unique member within the virus family Nimaviridae, is the most notorious aquatic virus infecting shrimp and other crustaceans and has caused enormous economic losses in the shrimp farming industry worldwide. Therefore, a comprehensive understanding of WSSV morphogenesis, structural proteins, and replication is essential for developing prevention measures of this serious parasite. The viral genome is approximately 300kb and contains more than 180 open reading frames (ORF). However, most of proteins encoded by these ORF have not been characterized. Due to the importance of WSSV structural proteins in the composition of the virion structure, infection process and interaction with host cells, knowledge of structural proteins is essential to understanding WSSV entry and infection as well as for exploring effective prevention measures. This review article summarizes mainly current investigations on WSSV structural proteins including the relative quantities, localization, function and protein-protein interactions. Traditional proteomic studies of 1D or 2D gel electrophoresis separations and mass spectrometry (MS) followed by database searches have identified a total of 39 structural proteins. Shotgun proteomics and iTRAQ were initiated to identify more structural proteins. To date, it is estimated that WSSV is assembled by at least 59 structural proteins, among them 35 are defined as the envelope fraction (including tegument proteins) and 9 as nucleocapsid proteins. Furthermore, the interaction within several major structural proteins has also been investigated. This identitification and characterization of WSSV protein components should help in the understanding of the viral assembly process and elucidate the roles of several major structural proteins.

Production and Characterization of Monoclonal Antibodies of Shrimp White Spot Syndrome Virus Envelope Protein VP28 / 中国病毒学

BALB/c mice were immunized with purified White spot syndrome virus (WSSV).Six monoclonal antibody cell lines were selected by ELISA with VP28 protein expressed in E.coll in vitro neutralization experiments showed that 4 of them could inhibit the virus infection in crayfish.Westernblot suggested that all these monoclonal antibodies were against the conformational structure of VP28.The monoclonal antibody 7B4 was labeled with colloidal gold particles and used to locate the VP28 on virus envelope by immunogold labeling.These monoclonal antibodies could be used to develop immunological diagnosis methods for WSSV infection.

Development of Lateral-flow Immunoassay for WSSV with Polyclonal Antibodies Raised against Recombinant VP (19+28) Fusion Protein / 中国病毒学

We have developed a sensitive and rapid lateral-flow immunoassay (LFIA) for WSSV,using colloidal gold as an indicator.The fusion protein,VP (19+28),was expressed in E.coli,purified and used to prepare polyclonal antibodies.The purified anti-VP (19+28) IgG were conjugated with colloidal gold.Unconjugated anti-VP (19+28) IgG and goat anti-rabbit IgG were immobilized on nitrocellulose membranes.After assembly,three groups (5 individual animals in each group) of shrimp samples were tested which included healthy,moribund and dead shrimps.For each group,three different tissues (body juices,gills and hepatopancreas) were tested at the same time.In parallel,all the samples were also analyzed using PCR for comparison.Out of 45 samples tested,30 were detected as positive while 15 were classified as negative.The results of LFIA correlate with those obtained by the PCR analysis,indicating that these two detection methods have the same efficacy in the limited number of samples tested in this preliminary study.