TLR21 is involved in the NF-κB and IFN-β pathways in largemouth bass (Micropterus salmoides) and interacts with TRIF but not with the Myd88 adaptor.

Toll-like receptors (TLRs) are pattern recognition receptors that trigger host immune responses against various pathogens by detecting evolutionarily conserved pathogen-associated molecular patterns (PAMPs). TLR21 is a member of the Toll-like receptor family, and emerging data suggest that it recognises unmethylated CpG DNA and is considered a functional homologue of mammalian TLR9. However, little is known regarding the role of TLR21 in the fish immune response.

Genome-Wide Identification, Sequence Alignment, and Transcription of Five Sex-Related Genes in Largemouth Bass ().

Background: Largemouth bass () is an economically important fish species in China. Most research has focused on its growth, disease resistance, and nutrition improvement. However, the sex-determining genes in largemouth bass are still unclear.

Development of a Highly Permissive Mandarin Fish () Kidney Cell Line for Mandarin Fish Ranavirus Using a Single-Cell Cloning Method.

Mandarin fish ranavirus (MRV) infection poses a substantial challenge to the mandarin fish culture industry as no effective preventive or therapeutic measures currently exist. The creation of a highly permissive cell line from a natural host is crucial for developing a vaccine for MRV and understanding its pathogenic mechanisms. In this research, the mandarin fish () kidney cell line (SCK) was isolated from mandarin fish kidneys.

Molecular characterization, expression and functional analysis of TAK1, TAB1 and TAB2 in Nile tilapia (Oreochromis niloticus).

The MAPK pathway is the common intersection of signal transduction pathways such as inflammation, differentiation and proliferation and plays an important role in the process of antiviral immunity. Streptococcus agalactiae will have a great impact on tilapia aquaculture, so it is necessary to study the immune response mechanism of tilapia to S. agalactiae.

Nile tilapia TBK1 interacts with STING and TRAF3 and is involved in the IFN-β pathway in the immune response.

Nile tilapia (Oreochromis niloticus) occupies an important position in the culture of economic fish in China. However, the high mortality caused by streptococcal disease has had a significant impact on the tilapia farming industry. Therefore, it is necessary to clarify the immune mechanism of tilapia in response to Streptococcus agalactiae.

Genomic organization and gene evolution of two warm temperature acclimation proteins (Wap65s) of Micropterus salmoides and their responses to temperature and bacterial/viral infections.

Warm temperature acclimation-related 65-kDa proteins (Wap65s) are fish plasma acute-phase glycoproteins homologous to hemopexin with high affinity and clearance for heme. The study characterized Mswap65-1 and Mswap65-2 genes in Micropterus salmoides. Structural analysis showed MsWap65s contained conserved heme-binding sites.

Whole-genome resequencing reveals recent signatures of selection in five populations of largemouth bass ( ).

Largemouth bass ( ) is an economically important fish species in North America, Europe, and China. Various genetic improvement programs and domestication processes have modified its genome sequence through selective pressure, leaving nucleotide signals that can be detected at the genomic level. In this study, we sequenced 149 largemouth bass fish, including protospecies (imported from the US) and improved breeds (four domestic breeding populations from China).

Exposure to heat stress causes downregulation of immune response genes and weakens the disease resistance of Micropterus salmoides.

In order to understand the molecular mechanism of response to heat stress in largemouth bass (LMB) Micropterus salmoides, we performed transcriptome analysis of spleen tissue of LMB subjected to heat stress and challenged with A. veronii under heat stress. A total of 2162 DEGs were identified between the heat stressed (32 °C) and control groups (24 °C) after 7 d treatment.

Comparative Analysis of the Gut Microbiota of Mandarin Fish () Feeding on Compound Diets and Live Baits.

feeds on live fry throughout their life. The sustainable development of its farming industry has urgently necessitated the development of artificial diets to substitute live baits. It has been demonstrated that gut microbiota assists in feed adaptation and improves the feed conversion rate in fish.

Characterization of kiss2/kissr2 system in largemouth bass (Micropterus salmoides) and Kiss2-10 peptide regulation of the hypothalamic-pituitary-gonadal axis.

The kisspeptin system, which lies upstream of the hypothalamic-pituitary-gonadal (HPG) axis, is believed to function as a regulator of reproduction in teleosts. In this study, we isolated and characterized kiss2 and its receptor kissr2 in largemouth bass (Micropterus salmoides). The complete coding sequences of kiss2 and kissr2 were 375 and 1134 bp long and encoded precursor proteins 124 and 377 amino acid long, respectively.

Asymmetric expression of homoeologous genes contributes to dietary adaption of an allodiploid hybrid fish derived from Megalobrama amblycephala (♀) × Culter alburnus (♂).

Background: Hybridization, which can quickly merge two or more divergent genomes and form new allopolyploids, is an important technique in fish genetic breeding. However, the merged subgenomes must adjust and coexist with one another in a single nucleus, which may cause subgenome interaction and dominance at the gene expression level and has been observed in some allopolyploid plants. In our previous studies, newly formed allodiploid hybrid fish derived from herbivorous Megalobrama amblycephala (♀) × carnivorous Culter alburnus (♂) had herbivorous characteristic.

Next-generation sequencing of the mitochondrial genome of (Percichthyoidei: Percichthyidae).

The belongs to family Maccullochella, and is distributed in Australia and South America (mainly Argentina and Chile). In this paper, the complete mitochondrial genome of was determined using next-generation sequencing. The whole mitogenome is a typical circular DNA molecule of 16,442 bp and contains 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and a D-loop region, with the base composition of A 31.

Comparative Genomics Studies on the Gene Family in Fish.

Doublesex and mab-3-related transcription factor () genes are widely distributed across various biological groups and play critical roles in sex determination and neural development. Here, we applied bioinformatics methods to exam cross-species changes in the dmrt family members and evolutionary relationships of the genes based on genomes of 17 fish species. All the examined fish species have while only five species contained Most fish harbored two paralogs ( and ), with being unique to fish.

Correlation analysis of mandarin fish () growth hormone gene polymorphisms and growth traits.

Screening of trait-associated molecular markers can be used to enhance the efficiency of selective breeding. Previously, we produced the first high-density genetic linkage map for the mandarin fish () and identified 11 quantitative-trait loci significantly associated with growth, of which one is located within the growth hormone () gene. To investigate the gene polymorphisms and their correlation with growth, the complete sequence was cloned and 32 single-nucleotide polymorphisms (SNPs) and one simple-sequence repeat (SSR) were identified.

Phylogenetic analysis of sooty grunter and other major freshwater fishes in the suborder Percoidei based on mitochondrial DNA.

Perciformes is the largest order of fishes and vertebrates. Sooty grunter (Hephaestus fuliginosus) is an economic fish species in the Terapontidae family of Percoidei, a suborder within Perciformes. To conduct molecular-level analysis of the phylogenetic relationships between sooty grunter and major freshwater fishes in Percoidei, we analysed the entire sooty grunter mitochondrial genome sequence and obtained the mitochondrial genome information of 19 fishes from Terapontidae, Serranidae, and Centrarchidae families in Percoidei from GenBank.

Cloning, SNP detection, and growth correlation analysis of the 5' flanking regions of two myosin heavy chain-7 genes in Mandarin fish (Siniperca chuatsi).

Myosin heavy chains (MYHs) play important roles in muscle growth and contraction. In fish, MYHs contribute to hyperplasia and hypertrophy of muscle fibers, which can continue into adult life and thus result in indeterminate growth in some species. We previously identified two MYH genes, MYH-7a and MYH-7b, that are differentially expressed in Mandarin fish (Siniperca chuatsi) and appear to function in early growth.

Interaction of Group B Streptococcus sialylated capsular polysaccharides with host Siglec-like molecules dampens the inflammatory response in tilapia.

Group B Streptococcus (GBS, S. agalactiae) infection in tilapia (Oreochromis niloticus) causes widespread death of this species and is a significant issue for the aquaculture industry. The major virulence factor for GBS is its sialylated capsular polysaccharides (CPs).

Construction of a high-density linkage map and mapping of sex determination and growth-related loci in the mandarin fish (Siniperca chuatsi).

Background: The mandarin fish (Siniperca chuatsi) is an important and widely cultured fish in China. However, the lack of selective breeding of mandarin fish in previous decades has resulted in a decline in the growth rate of pond-cultured fish, a shortened period of sexual maturity, and reduced disease resistance; these issues seriously affect the quality and safety of the fish products. Therefore, it is necessary to establish a selective breeding program for the mandarin fish to improve the economical traits of the fish and to sustain the development of the mandarin fish industry.

Grass carp reovirus-GD108 fiber protein is involved in cell attachment.

Viral attachment to specific host receptors is the first step in viral infection and serves an essential function in the selection of target cells. In this study, structure analysis, neutralization assays, and cell attachment assays were carried out to evaluate the cell attachment functions of the outer capsid fiber protein of grass carp reovirus GD108 strain (GCRV-GD108). The GCRV-GD108 fiber protein contained 512 amino acids encoded by S7 segment and shared sequence similarities with mammalian reovirus cell attachment protein σ1 and adenovirus fiber.

Discovery and expression of 3 siglecs-like in Oreochromis niloticus neutrophil, and their interaction with group B streptococcal sialylated capsular polysaccharides.

Sialic acid - binding immunoglobulin - like lectins (Siglecs) are members of the largest superfamily of immune receptors; they recognize sialic acid and are mainly expressed in immune cells. Studies on mammals indicate that Streptococcus agalactiae (GBS) evade immune reactions by interacting with the host immune cells via the sialic acid of sialylated capsular polysaccharides. However, it is currently unknown if fish-derived GBS can interact with Siglecs to evade host immunity.

Β-defensin in Nile tilapia (Oreochromis niloticus): Sequence, tissue expression, and anti-bacterial activity of synthetic peptides.

Beta-defensins (β-defensins) are small cationic amphiphilic peptides that are widely distributed in plants, insects, and vertebrates, and are important for their antimicrobial properties. In this study, the β-defensin (Onβ-defensin) gene of the Nile tilapia (Oreochromis niloticus) was cloned from spleen tissue. Onβ-defensin has a genomic DNA sequence of 674 bp and produces a cDNA of 454 bp.

Two myostatin genes exhibit divergent and conserved functions in grass carp (Ctenopharyngodon idellus).

Myostatin (MSTN) is an important negative regulator of myogenesis, which inhibits myoblast proliferation and differentiation. Here, we report the isolation and characterization of two mstn genes in grass carp (Ctenopharyngodon idellus). Grass carp mstn-1 and mstn-2 cDNAs are highly divergent, sharing a relatively low amino acid sequence identity of 66%.

Transcriptome profiling and digital gene expression analysis of Nile tilapia (Oreochromis niloticus) infected by Streptococcus agalactiae.

Tilapia is an important freshwater aquaculture species worldwide. In recent years, streptococcal diseases have severely threatened development of tilapia aquaculture, while effective prevention and control methods have not yet been established. In order to understand the immunological response of tilapia to infection by Streptococcus agalactiae (S.