Development of Nucleic Acid Sequence-Based Amplification Assay for Detection of Macrobrachium rosenbergii Nodavirus

A nucleic acid sequence-based amplification（NASBA）assay was established for the detection of Macrobrachium rosenbergii Nodavirus（MrNV）.The specific primers were designed according to the high conserved region of RNA2 sequence of MrNV.The 224 bp specific amplification product was obtained in positive sample determined with 3%agarose gel electrophoresis,while no product was generated from shrimp infected with other viruses including DNA viruses（IHHNV,WSSV）and RNA viruses（TSV,IMNV,YHV）.The detecting limit of the assay was 8pg nucleic acid,which is more sensitive than that of PCR method.

Identification and functional characterization of fish IL‑17 receptors suggest important roles in the response to nodavirus infection

Th17 is a lymphocyte T helper(Th)subpopulation relevant in the control and regulation of the immune response characterized by the production of interleukin(IL)-17.This crucial cytokine family acts through their binding to the IL-17 receptors(IL-17R),having up to six members.Although the biology of fish Th17 is well-recognized,the molecular and functional characterization of IL-17 and IL-17R has been limited.Thus,our aim was to identify and characterize the IL-17R repertory and regulation in the two main Mediterranean cultured fish species,the gilthead seabream(Sparus aurata)and the European sea bass(Dicentrarchus labrax).Our in silico results showed the clear identification of six members in each fish species,from IL-17RA to IL-17RE-like,with well-conserved gene structure and protein domains with their human orthologues.All of them showed wide and constitutive transcription in naïve tissues but with highest levels in mucosal tissues,namely skin,gill or intestine.In leucocytes,T mitogens showed the strongest up-regulation in most of the il17 receptors though il17ra resulted in inhibition by most stimulants.Interestingly,in vivo nodavirus infection resulted in alterations on the transcription of il17 receptors.While nodavirus infection led to some increments in the il17ra,il17rb,il17rc and il17rd transcripts in the susceptible European sea bass,many down-regulations were observed in the resistant gilthead seabream.Our data identify the presence and conservation of six coding IL-17R in gilthead seabream and European sea bass as well as their differential regulation in vitro and upon nodavirus infection.

Newly discovered insect RNA viruses in China

Insects are a group of arthropods and the largest group of animals on Earth,with over one million species described to date.Like other life forms,insects suffer from viruses that cause disease and death.Viruses that are pathogenic to beneficial insects cause dramatic economic losses on agriculture.In contrast,viruses that are pathogenic to insect pests can be exploited as attractive biological control agents.All of these factors have led to an explosion in the amount of research into insect viruses in recent years,generating impressive quantities of information on the molecular and cellular biology of these viruses.Due to the wide variety of insect viruses,a better understanding of these viruses will expand our overall knowledge of their virology.Here,we review studies of several newly discovered RNA insect viruses in China.