Anti-white Spot Syndrome Virus Research Articles

Applying Modified VP53A Recombinant Protein as an Anti-White Spot Syndrome Virus Biological Agent in Litopenaeus vannamei Farming.

Shrimp farming is an important economic activity. However, due to the spread of pathogens, shrimp aquaculture is becoming increasingly difficult. Many studies have confirmed that white spot syndrome virus (WSSV) recombinant proteins can inhibit viral infection. Among them, VP53 recombinant protein has been found to reduce mortality upon WSSV challenge. This study was conducted in Kaohsiung, Taiwan and reports the first field feeding trial to demonstrate that WSSV recombinant proteins can improve shrimp survival rates at a farming scale. Prior to the feeding trial, the shrimp were confirmed to be slightly infected with WSSV, Vibrio parahaemolyticus strains causing acute hepatopancreatic necrosis disease (AHPND), non-AHPND V. parahaemolyticus strains, and Enterocytozoon hepatopenaei (EHP), which are common pathogens that shrimp farmers often face. The shrimp were then divided into two groups: a control group (C group) fed with a commercial diet and a protein group (P group) fed with the same commercial feed with VP53 recombinant protein. Our findings indicated that the survival rate and expression of immune genes of the P group were higher than those of the C group. The intestinal microbiota of the two groups were also analysed. Collectively, our results confirmed that the recombinant WSSV envelope protein derivative can be used as an effective anti-virus biological agent in shrimp farms.

Small Molecule Inhibitors of White Spot Syndrome Virus: Promise in Shrimp Seedling Culture.

Rapid production of prawn (Litopenaeus vannamei) under artificial pressure can result in a series of obvious challenges and is vulnerable to serious losses related to aquatic environmental issues and the unrestrained outbreak of white spot syndrome (WSS). However, to date, there are no therapeutic strategies to contain the spread of the virus. Here, we synthesized 27 coumarin derivatives and evaluated their anti-white spot syndrome virus (WSSV) activity in L. vannamei larvae. We demonstrated that electron-withdrawing and electron-giving substituent groups play an important role in reducing toxicity and WSSV replication, respectively. Two coumarin C2 (2-amino-5-oxo-4-(p-tolyl)-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile) and C7 (2-amino-4-(4-chlorophenyl)-5-oxo-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile) were regarded as the most promising anti-WSSV compounds with maximum antiviral response <5% and median effective concentration <10 mg/L. The mortality of WSSV-infected larvae decreased by more than 60% after exposure to C2 and C7. With continuous immersion of C2 and C7 exchange, the mortality further decreased to 40% at 120 h. Additionally, C2 and C7 are the relatively stable in aquacultural water, making these agents suitable for use in inhibiting WSSV horizontal transmission in static aquaculture systems. These results showed the marked advantages of using C2 and C7 in the shrimp industry, and suggest that they hold potential for the treatment and prevention of WSSV infection in shrimp seedling culture.

Difference in medication pattern potentially enhances antiviral efficiency of a novel amino-fluorophenyl compound on WSS risk in shrimp seedling culture

As an important upstream industry of prawn farming, shrimp seedling culture is extremely vulnerable to serious losses related to the unrestrained outbreak of white spot syndrome (WSS). The incomplete innate immune system of shrimp larvae may contribute to the difficulty in containing the spread of the virus with most treatment strategies. In order to solve this dilemma, in this study, we designed, synthesized and screened 2-amino-4-(4-fluorophenyl)-5-oxo-4H,5H-pyrano[3,2-c]chromene-3‑carbonitrile (C5) from our molecule drug library to seek its appropriate application in shrimp seedling culture. After evaluation on the anti-White Spot Syndrome Virus (WSSV) activity in Litopenaeus vannamei larvae, C5 was regarded as a promising anti-WSSV medicine with a maximum antiviral rate > 93% and significantly decreased 60% mortality of WSSV-infected larvae in a dose-dependent manner at 72 h post-infection (hpi). When WSSV was pre-incubated with 10 mg/L of C5 for 1–4 h, viral infectivity was greatly weakened by a lower lethality up to 58% at 144 hpi. In view of antiviral stability of C5 in aquacultural water within 2 days, continuous C5 exchange was performed, suggesting an obvious decrease of viral load and the increased survival of WSSV-infected larvae up to 50% at 144 hpi. Interestingly, continuous water exchange also contributed to improve the survival rate, which was necessary for shrimp larvae to eliminate excess organic pollutants. These results suggest that C5 hold potential for the treatment of WSSV infection in shrimp seedling culture.

Cynodon dactylon as potential anti-white spot syndrome virus agent in cultured shrimp Penaeus vannamei

White spot syndrome virus (WSSV) has been listed as the most contagious pathogen causing severe mortality in farmed shrimp and substantial economic losses. A bioassay experiment was conducted to determine Cynodon dactylon extract's efficacy as an anti-WSSV treatment at the laboratory scale and cage level. A pond trial was performed to optimize and investigate the effects of C. dactylon-enriched feed. The trial's first step was performed using feed coated with 2% and 3% of ethanol-extracted C. dactylon. The shrimp were challenged with the virus on day 15 of feeding with the treatment feed and monitored. A total of 100% survival of shrimp was obtained in both treatment groups. The (Rajeev anti-viral) RAV-s C group had the best protection (100% survival) of three groups treated with crude extracts, including RAV-s A (10%), RAV-s B (15%) and RAV-s C (20%) mixed feed. Similar results were obtained in the cage level trial with crude extracts, where the RAV-s C group had the highest survival (100%) followed by RAV-s A (68%) and RAV-s B (85.05%). Pond trials were conducted in commercial ponds. A total of 20 units of shrimp ponds of the same size (5,000 m2) and location were selected for the trial. The treatment ponds' productivity was higher (12.7 ton/ha) than that of the control ponds (11.79 ton/ha). WSSV cases were not recorded in the control and treatment ponds. This study showed that C. dactylon extract has anti-WSSV properties and has no negative impact on shrimp growth.

Electrochemical detection of white spot syndrome virus with a silicone rubber disposable electrode composed of graphene quantum dots and gold nanoparticle-embedded polyaniline nanowires

BackgroundWith the enormous increment of globalization and global warming, it is expected that the number of newly evolved infectious diseases will continue to increase. To prevent damage due to these infections, the development of a diagnostic method for detecting a virus with high sensitivity in a short time is highly desired. In this study, we have developed a disposable electrode with high-sensitivity and accuracy to evaluate its performances for several target viruses.ResultsConductive silicon rubber (CSR) was used to fabricate a disposable sensing matrix composed of nitrogen and sulfur-co-doped graphene quantum dots (N,S-GQDs) and a gold-polyaniline nanocomposite (AuNP-PAni). A specific anti-white spot syndrome virus (WSSV) antibody was conjugated to the surface of this nanocomposite, which was successfully applied for the detection of WSSV over a wide linear range of concentration from 1.45 × 102 to 1.45 × 105 DNA copies/ml, with a detection limit as low as 48.4 DNA copies/ml.ConclusionThe engineered sensor electrode can retain the detection activity up to 5 weeks, to confirm its long-term stability, required for disposable sensing applications. This is the first demonstration of the detection of WSSV by a nanofabricated sensing electrode with high sensitivity, selectivity, and stability, providing as a potential diagnostic tool to monitor WSSV in the aquaculture industry.

Polyhydroxy Isocopalane from Indonesian’s Marine Sponge Callyspongia Sp. as Anti–White Spot Syndrome Virus from Litopenaeus vannamei

The study of Indonesian’s marine sponge Callyspongia Sp. against white spot syndrome virus has been conducted in June 2017. Bioactive metabolite terpene isolated based on methods of bioassay-guided separation. LCMS-ESI spectrum indicate that molecular formula C24H44O5 with molecular weight is 412.576 m/z. FTIR spectrum indicated bioactive metabolite has ether C-O group at 1261 cm-1 and hydroxy group O-H at 3419 cm-1. The spectrum of 1H NMR and 13C NMR indicated that metabolite active compound as polyhydroxy isocopalane. The antiviral activity of isolate compound has been conducted against white spot syndrome virus from Litopenaeus vannamei. The result antiviral activity showed that the compound activity is strong at concentration 60 mg/L with survivability percentage at 34%. The result indicated that polyhydroxy isocopalane has an activity as anti-white spot syndrome activity from Litopenaeus vannamei.

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

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. 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. 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. 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

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. 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. 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. The drug MP07X derived from Rhizophora mucronata is a potent anti-WSSV drug.

Characterization of a 2-Cys peroxiredoxin IV in Marsupenaeus japonicus (kuruma shrimp) and its role in the anti-viral immunity

Accumulating evidence suggests that peroxiredoxins (Prx) are key molecules in the pathogenesis of various infectious diseases and are potential therapeutic targets for major diseases such as cancers. In this study, we report a peroxiredoxin IV (Prx IV) in Marsupenaeus japonicus, designated as MjPrx IV, which exhibited peroxidase activity and participated in the anti-white spot syndrome virus (WSSV) immune response. MjPrx IV is a 245-amino acid polypeptide with a predicted 19-amino acid signal peptide, an Ahpc-TSA domain, and a 1-Cys PrxC domain. Phylogenetic analysis revealed that the protein belongs to the Prx IV subfamily. MjPrx IV transcripts were detected in the gills, hepatopancreas, heart, stomach, ovaries, spermary, and intestine tissues, and are upregulated in the gonads, gills and hemocytes of shrimp after WSSV challenge. The mature MjPrx IV peptide was recombinantly expressed in an Escherichia coli system. The protein exhibited peroxidase activity. Furthermore, dsRNA suppression of MjPrx IV increased WSSV replication in shrimp, whereas rMjPrx IV injection into shrimp decreased WSSV replication. These data suggest that MjPrx IV has an important role in shrimp antiviral immunity. To our knowledge, this study is the first to report a shrimp Prx IV that has anti-WSSV activity.