Molecular characterization and expression analysis of nine toll like receptor (TLR) genes in Scortum barcoo under Streptococcus agalactiae infection.

Toll like receptors (TLRs) are important pattern recognition receptors participating in innate immune system. Up to now, no TLR has been identified in Jade perch (Scortum barcoo). In this study, we successfully identified 9 members of TLRs from the Jade perch. Amino acid sequence alignment analysis showed that the whole sequences of these TLRs were highly conserved among different fish species, especially in LRR, TM and TIR domains. Phylogenetic analysis revealed that each SbTLR was successfully grouped into corresponding gene family of teleosts. Expression analysis showed that most SbTLRs mainly expressed in liver, spleen, muscle and skin, while expressed less in brain and stomach. After Streptococcus agalactiae infection, expression of SbTLR2, SbTLR5S and SbTLR22 were significantly upregulated, while SbTLR3, SbTLR5M, SbTLR9, SbTLR13, and SbTLR14 were significantly downregulated. In all, this research first reported molecular characterization and expression profiles of 9 TLRs in Jade perch. These data will make a contribution for better understanding the antibacterial mechanism of TLRs in teleosts.

Characterization and expression analysis of the interferon regulatory factor (IRF) gene family in zig-zag eel (Mastacembelus armatus) against Aeromonas veronii infection.

Interferon regulatory factors (IRFs) play an important role in innate and adaptive immune system. However, in teleosts, the data on IRFs is still scarce. Here, for the first time, we identified 11 members of IRFs from the zig-zag eel Mastacembelus armatus (MarIRF1-10). The deduced protein sequences are highly conserved among different fish species especially in DBD and IAD domain. Phylogenetic analysis indicated that MarIRFs preferentially grouped with fish species in Synbranchiformes or Perciformes. Expression analysis showed that MarIRFs were expressed in all nine tissues including spleen, gill, muscle and intestine. After infected by Aeromonas veronii, expression of MarIRF2, MaIRF4b and MaIRF5 were significantly upregulated in spleen, MarIRF1, MarIRF2 were significantly upregulated in kidney, but in liver, nearly all MarIRFs were downregulated. Taken together, this study first reported molecular characterization and expression patterns of 11 IRFs in the zig-zag eel. All these results will contribute a lot to better understanding the antibacterial mechanism of IRFs in teleosts.

De Novo Assembly, Characterization and Comparative Transcriptome Analysis of the Mature Gonads in Spinibarbus hollandi.

Spinibarbus hollandi is an important commercial aquaculture species in southeastern China, but with long maturity period and low egg laying amount. However, there has been little study of its gonad development and reproductive regulation, which limits aquaculture production. Here, for the first time, gonadal transcriptomes of male and female S. hollandi were analyzed. A total of 167,152 unigenes were assembled, with only 48,275 annotated successfully. After comparison, a total of 21,903 differentially expressed genes were identified between male and female gonads, of which 16,395 were upregulated and 5508 were downregulated in the testis. In addition, a large number of differentially expressed genes participating in reproduction, gonad formation and differentiation, and gametogenesis were screened out and the differential expression profiles of partial genes were further validated using quantitative real-time PCR. These results will provide basic information for further research on gonad differentiation and development in S. hollandi.