Advances in the study of nodavirus

Abstract

Nodaviruses are small bipartite RNA viruses which belong to the family of Nodaviridae. They are categorized into alpha-nodavirus, which infects insects, and beta-nodavirus, which infects fishes. Another distinct group of nodavirus infects shrimps and prawns, which has been proposed to be categorized as gamma-nodavirus. Our current review focuses mainly on recent studies performed on nodaviruses. Nodavirus can be transmitted vertically and horizontally. Recent outbreaks have been reported in China, Indonesia, Singapore and India, affecting the aquaculture industry. It also decreased mullet stock in the Caspian Sea. Histopathology and transmission electron microscopy (TEM) are used to examine the presence of nodaviruses in infected fishes and prawns. For classification, virus isolation followed by nucleotide sequencing are required. In contrast to partial sequence identification, profiling the whole transcriptome using next generation sequencing (NGS) offers a more comprehensive comparison and characterization of the virus. For rapid diagnosis of nodavirus, assays targeting the viral RNA based on reverse-transcription PCR (RT-PCR) such as microfluidic chips, reverse-transcription loop-mediated isothermal amplification (RT-LAMP) and RT-LAMP coupled with lateral flow dipstick (RT-LAMP-LFD) have been developed. Besides viral RNA detections, diagnosis based on immunological assays such as enzyme-linked immunosorbent assay (ELISA), immunodot and Western blotting have also been reported. In addition, immune responses of fish and prawn are also discussed. Overall, in fish, innate immunity, cellular type I interferon immunity and humoral immunity cooperatively prevent nodavirus infections, whereas prawns and shrimps adopt different immune mechanisms against nodavirus infections, through upregulation of superoxide anion, prophenoloxidase, superoxide dismutase (SOD), crustin, peroxinectin, anti-lipopolysaccharides and heat shock proteins (HSP). Potential vaccines for fishes and prawns based on inactivated viruses, recombinant proteins or DNA, either delivered through injection, oral feeding or immersion, are also discussed in detail. Lastly, a comprehensive review on nodavirus virus-like particles (VLPs) is presented. In recent years, studies on prawn nodavirus are mainly focused on Macrobrachium rosenbergii nodavirus (MrNV). Recombinant MrNV VLPs have been produced in prokaryotic and eukaryotic expression systems. Their roles as a nucleic acid delivery vehicle, a platform for vaccine development, a molecular tool for mechanism study and in solving the structures of MrNV are intensively discussed.

Molecular biology of Macrobrachium rosenbergii nodavirus infection in giant freshwater prawn

“…The increasing number of diagnostic tools such as immunodiagnostic and molecular‐based tools has been reported for the detection of Mr NV. The recent development of detection tools has been reviewed in general to aquatic animal (Hine et al., ; Ninawe, Hameed, & Selvin, ); shrimp‐related infectious diseases (Flegel, ; Thitamadee et al., ); and a relatively more comprehensive review in particular to the detection of nodaviruses (Yong, Yeap, Omar, & Tan, ) and different virus infection in M. rosenbergii (Bonami & Widada, ). However, most of the detection tools remain un‐robust and challenging in terms of technical, time‐consuming and costly, and least conform to the reality practice in the aquaculture farm.…”

“…Scanty reports of other approaches, for instances the assessment of genetic variation/inheritance in selective breeding of disease‐resistant strains (Luan et al., ) and the use of natural products of plant extracts (Farook et al., ; Khanna, Kannabiran, Babu, & Hameed, ), are available. Several critical review articles have been published in the past 10 years, revolving the general issues of biosecurity in sustainable aquaculture (Hine et al., ), in particular, infectious diseases of cultured aquatic animals (Thitamadee et al., ; Yong et al., ); and specific focuses on WTD in M. rosenbergii (Bonami & Widada, ; Hameed & Bonami, ; Na‐Nakorn & Jintasataporn, ; Pillai & Bonami, ). But none of these articles have reviewed the emerging aptamers technology in the disease diagnosis of aquatic animal and its potential prophylactic and therapeutic properties.…”

“…Thus, comprehending the mechanisms of cellular apoptosis during virus infection is essential in providing new insight into crustaceans' immunity to mitigate disease progression and eluding mortality due to infection. been reviewed in general to aquatic animal (Hine et al, 2010;Ninawe, Hameed, & Selvin, 2017); shrimp-related infectious diseases (Flegel, 2012;Thitamadee et al, 2016); and a relatively more comprehensive review in particular to the detection of nodaviruses (Yong, Yeap, Omar, & Tan, 2017) and different virus infection in M. rosenbergii (Bonami & Widada, 2011 (Kumar, Karunasagar, & Karunasagar, 2013;Sahoo et al, 2012) and technology of aptamers that is also known as the synthetic antibody (Aoki & Hirono, 2013;Hwang et al, 2012;Li et al, 2014;Zhou et al, 2016). Scanty reports of other approaches, for instances the assessment of genetic variation/ inheritance in selective breeding of disease-resistant strains (Luan et al, 2015) and the use of natural products of plant extracts (Farook et al, 2016;Khanna, Kannabiran, Babu, & Hameed, 2011), are available.…”

“…Scanty reports of other approaches, for instances the assessment of genetic variation/ inheritance in selective breeding of disease-resistant strains (Luan et al, 2015) and the use of natural products of plant extracts (Farook et al, 2016;Khanna, Kannabiran, Babu, & Hameed, 2011), are available. Several critical review articles have been published in the past 10 years, revolving the general issues of biosecurity in sustainable aquaculture (Hine et al, 2010), in particular, infectious diseases of cultured aquatic animals (Thitamadee et al, 2016;Yong et al, 2017); and specific focuses on WTD in M. rosenbergii (Bonami & Widada, 2011;Hameed & Bonami, 2012;Na-Nakorn & Jintasataporn, 2012;Pillai & Bonami, 2012 (Aoki & Hirono, 2013;Li et al, 2014;, 2017 and the detection of virus-infected cells Li et al, , 2018, and aptamers that manifesting antiviral property (Hwang et al, 2012;Li et al, 2014;. Among the approaches to construct attenuated live synthetic viruses include genome-scale changes in codon-pair bias (Mueller et al, 2010) and codon de-optimization (Evenson et al, 2016;Martínez, Jordan-Paiz, Franco, & Nevot, 2016).…”

Comparative genome analysis reveals a distinct influence of nucleotide composition on virus–host species‐specific interaction of prawn‐infecting nodavirus

“…This includes alpha‐, beta‐ and the proposed gammanodavirus, which were characterized as a small, non‐enveloped, isometric RNA virus that belongs to the family of Nodaviridae (Ravi, Nazeer Basha, Taju, Ram Kumar, & Sahul Hameed, ). The nodavirus consists of bipartite positive single‐stranded RNA genome, RNA 1 and RNA 2 with methylated caps at their 5′ ends but lack of poly(A) tails that were encapsulated in the icosahedral capsid (Yong, Yeap, Omar, & Tan, ). The larger segment (3.1 kb) of RNA 1 encodes the RNA‐dependent RNA polymerase (RdRp) that replicates the viral genome, whereas the RNA 2 (1.4 kb) encodes the virus capsid protein precursor (Cp).…”