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In total 374 specimens corresponding to four species of shrimp: Artemesia longinaris, Pleoticus muelleri, Peisos petrunkevitchii, Palaemon macrodactylus, and two species of crabs: Neohelice granulata and Cyrtograpsus angulatus were studied in the search of white spot syndrome virus (WSSV). The crustaceans were collected in the estuary of Bahia Blanca, the port of Mar del Plata and the Samborombón Bay, Argentina, between 2010 and 2014. A polymerase chain reaction (PCR) analysis in all of them has not detected any virus presence. These new results suggest that the discovery of infected shrimp in 2008-09 in the Bahia Blanca estuary may have been a one-time local event, promoted by special conditions of seawater temperature inside the estuary, coincident with the presence of a virus carrier or transporter. To determine if the virus was finally installed in the estuary of Bahia Blanca more screening are needed coming from a larger number of shrimp samples. These studies will be necessary mainly in A. longinaris (Penaeidae) since this family of shrimps is most susceptible to be affected by WSSV. [ABSTRACT FROM AUTHOR]

The aquaculture of penaeid shrimp has grown rapidly during the past three decades. However, shrimp aquaculture continues to be plagued by infectious disease, particularly of viral aetiology. Urgently needed are in vitro biological tools to facilitate early detection and diagnosis of penaeid shrimp viruses. An immediate need is the establishment of stable or continuous shrimp cell lines, which remains to be an elusive goal. Researchers have made significant advancements in the methodologies for primary shrimp cell culture. Also, new media and technologies including cell immortalization are presently under development. The principal goal of this review paper is to collate current attempts in the establishment of permanent shrimp cell lines by summarizing the latest research progress on penaeid shrimp cell culture studies, including general cultivation conditions, methods of cell preparation, types of media and their utilization and the development of immortal cell lines. In addition, current and potential applications of penaeid shrimp cell cultures in the various related research fields are also discussed in this review. [ABSTRACT FROM AUTHOR]

WSSV is one of the most harmful pathogeny in the pacific white shrimp, and genetic variations caused the strains of different virulence. MicroRNAs (miRNAs) involved in the regulation of virus defense. To understand the different virulence of WSSV on miRNA expression in Litopeneaus vannamei , the deep sequencing was performed to compare two small RNA libraries prepared from hepatopancreas of Litopeneaus vannamei infected with normal-virulence or low-virulence WSSV. Approximately 29,398,623 raw reads from normal-virulence library and 35,291,803 raw reads from low-virulence library were obtained. There were about 37 miRNAs homologs identified. Sixteen miRNAs were significantly up-regulated and twenty-one miRNAs were significantly down-regulated in normal-virulence infection library compared with low-virulence infection library. Of these, Igi-miR-1175-3p was the most significant different miRNA, followed by bmo-miR-1175-3p and ipu-miR-26b, respectively. The putative target genes for differentially expressed miRNAs were concerned with biological processes, signal meditated, cell differentiation and apoptosis, immune recognition and other more functions. The results will help to understand the miRNAs response to different virulence WSSV infection. [ABSTRACT FROM AUTHOR]

Apoptosis inducing factor (AIF) and cytochrome c (CYC) are two mitochondrial apoptogenic factors. In the present study, the cDNA sequences of AIF ( Lv AIF) and CYC ( Lv CYC) were cloned from Pacific white shrimp, Litopenaeus vannamei . The Lv AIF was 1664 bp, including a 5’-terminal untranslated region (UTR) of 154 bp, an open reading frame (ORF) of 1323 bp encoding a polypeptide of 440 amino acids (aa) and a 3′ UTR of 187 bp. The Lv CYC was 582 bp, including a 50 bp 5′ UTR, a 315 bp ORF encoding for 104 aa, and a 217 bp 3′ UTR. The deduced protein of Lv AIF contained a conserved Pyr_redox and AIF_C domain at the N-terminal and the predicted Lv CYC included a conservative cytochrome_C domain, respectively. Phylogenetic analysis revealed that Lv AIF belonged to AIF1 subfamily and showed a close relationship with AIF1 from vertebrates and Lv CYC showed the closest relationship with its counterparts from shrimp Marsupenaeus japonicus . Tissue expression profiles showed that both Lv AIF and Lv CYC existed in most tissues, with the most predominant expression of Lv AIF in intestine, then followed muscle and the weakest expression in gill. The highest expression of Lv CYC was detected in muscle, and the weakest expression was in hemocytes. Additionally, after white spot syndrome virus (WSSV) infection, the significant up-regulation of Lv AIF, Lv CYC and caspase 3 transcripts and the increase of pro-caspase 3 and active-caspase 3 protein were detected at most time points ( P < 0.05). However, all of the three genes down-regulated in hemocytes in the early stage after WSSV infection. WSSV proliferation and shrimp mortality showed a time-dependent manner and the production of ROS in hemocytes were significantly increased at 6 and 24 h after infection. Our results showed that the apoptotic genes AIF, CYC and caspase 3 might play crucial roles in hepatopancreas, however, the production of ROS in hemocytes might be important in shrimp defense against WSSV infection. [ABSTRACT FROM AUTHOR]

Envelope protein VP28 has been suggested as a candidate vaccine component to evoke a better protection against white spot syndrome virus ( WSSV). We have reported that Bacillus subtilis spores harbouring VP28 (rVP28-bs) can specifically protect shrimp against WSSV. However, the mechanism that supports the production of unique molecules induced by rVP28-bs to trigger specific immunity is originally unknown. It has recently been suggested that Dscam (Down syndrome cell adhesion molecule) plays an essential role in the alternative adaptive immunity of invertebrates. In this study, we compared the diversity of Litopenaeus vannamei Dscam (LvDscam) variable regions by different antigens immunization. A total of 13, 15 and 11 expressed alternative sequences were identified for N-terminal Ig2, N-terminal Ig3 and the entire Ig7 domain, respectively. More than half of the unique variants (16 out of 22) were found in the Ig2/Ig3 domains. Further analysis of the interaction between VP28 and unique Ig2/Ig3 variants was confirmed by both yeast two-hybrid and GST pull-down approach. We also found that the percentage of haemocytes phagocytosing WSSV was significantly higher ( P < 0.001) in the shrimp injected with control-siRNA (43.8 ± 2.2) than those with Dscam-siRNA (11.3 ± 5.4) in the rVP28-bs groups. With Dscam-siRNA injection, survivorship significantly decreased ( P < 0.001) in the rVP28-bs group after WSSV challenge. Our data suggested that LvDscam-mediated pathway may be involved in the specific immune response of shrimp against WSSV induced by rVP28-bs. [ABSTRACT FROM AUTHOR]

Since its emergence in the 1990s, White Spot Disease (WSD) has had major economic and societal impact in the crustacean aquaculture sector. Over the years shrimp farming alone has experienced billion dollar losses through WSD. The disease is caused by the White Spot Syndrome Virus (WSSV), a large dsDNA virus and the only member of the Nimaviridae family. Susceptibility to WSSV in a wide range of crustacean hosts makes it a major risk factor in the translocation of live animals and in commodity products. Currently there are no effective treatments for this disease. Understanding the molecular basis of disease processes has contributed significantly to the treatment of many human and animal pathogens, and with a similar aim considerable efforts have been directed towards understanding host-pathogen molecular interactions for WSD. Work on the molecular mechanisms of pathogenesis in aquatic crustaceans has been restricted by a lack of sequenced and annotated genomes for host species. Nevertheless, some of the key host-pathogen interactions have been established: between viral envelope proteins and host cell receptors at initiation of infection, involvement of various immune system pathways in response to WSSV, and the roles of various host and virus miRNAs in mitigation or progression of disease. Despite these advances, many fundamental knowledge gaps remain; for example, the roles of the majority of WSSV proteins are still unknown. In this review we assess current knowledge of how WSSV infects and replicates in its host, and critique strategies for WSD treatment. [ABSTRACT FROM AUTHOR]

The shrimp Litopenaeus vannamei, one of the most important species in world aquaculture, has seriously affected by infectious myonecrosis virus (IMNV) that causes up to 70% mortalities. With the aim of improving the development of new strategies for rapid and reliable diagnosis, we isolated IMNV, from L. vannamei farmed in Brazil, through a discontinuous sucrose gradient, and sequenced cDNA fragment encoding the major capsid protein from this virus. Nucleotides sequences corresponding to the viral capsid protein was obtained by RT-PCR and confirmed by automatic sequencing. Comparison with sequences which encode the capsid protein obtained from Indonesia isolates showed a high identity. [ABSTRACT FROM AUTHOR]

Abstract: While dsRNA has been used experimentally to inhibit replication and thus disease caused by several shrimp viruses, it can be tedious, time consuming and costly to produce. Here we describe a simple method for obtaining long-hairpin dsRNA from RNase III-minus HT115 Escherichia coli cells following its expression from a plasmid containing a RNA promoter. All the method requires is for bacterial cells to be fixed briefly in 75% ethanol in phosphate buffer saline (PBS) before suspension in 150mM NaCl. When injected into the haemal sinuses of shrimp, hairpin dsRNA specific to the PmRab7 gene prepared by this method was found to inhibit PmRab7 mRNA expression as effectively as hairpin dsRNA purified using TRIzol reagent. Shrimp injection of either dsRNA-PmRab7 or hairpin dsRNA specific to yellow head virus (YHV) prepared similarly also inhibited YHV replication effectively. Based on these findings, this simple and cheap method of producing dsRNA should be adaptable to various commercial-scale applications of RNA interference (RNAi) in shrimp. [Copyright &y& Elsevier]

Abstract: The Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV) is a single-stranded DNA virus that infects several penaeid shrimp species, provoking economic losses in farmed shrimp populations estimated at several million of dollars. Furthermore, IHHNV has historically been considered an important threat for wild shrimp populations, but its real measurable impact remains unknown. Currently no treatments are available against IHHNV, and research to develop potential antiviral strategies depends on a detailed understanding of the viral life cycle. However, the exact pathophysiological events underlying the development of metabolic changes in IHHNV-infected shrimp are still unknown. Thus, the biochemical changes caused by the IHHNV infection in plasma and hepatopancreas of the economically important shrimp species Penaeus vannamei were evaluated. Glucose, lactate, total protein, glycogen, triacylglycerides, cholesterol, and total lipids were measured in healthy and IHHNV-infected shrimp. Significant changes were observed in energy substrates (glucose, lactate, triacylglycerides and cholesterol), in plasma and hepatopancreas. These changes may indicate a temporal sequestration of the host-cell metabolic pathways by the virus to maximize its replication and propagation. [Copyright &y& Elsevier]