High density lipoprotein binding protein( HBP) plays an important role in lipid metabolism of animals. Lipids are indispensable energy materials for fishes,especially for carnivorous fishes with low utilization efficiency of carbohydrates. The single nucleotide polymorphism( SNP) of HBP gene may affect the fat metabolism,thereby exerting an effect on the growth traits of largemouth bass( Micropterus salmoides). Investigating the correlations between SNP and growth traits can provide candidate markers for molecular marker-assisted selection. In this study,partial genomic fragments of HBP gene( Gen Bank accession number:KF652241) were amplified based on the sequences of an available contig in the EST-SNP database of largemouth bass. Three SNP mutation loci were identified in the 3' non-coding region of HBP gene by direct sequencing,including H1( G + 2782T),H2( T + 2817C) and H3( G + 2857A). Three SNP loci of 165 randomly selected largemouth bass individuals were detected and genotyped by Sna Pshot assay. Genetic structure was analyzed by POPGENE32 software. By using spss17. 0software,a general linear model( GLM) was established for correlation analysis between different genotypes at SNP loci of HBP gene and various growth traits. The results showed that three SNP loci were in Hardy-Weinberg equilibrium state. To be specific,loci H1 and H2 formed two haplotypes( A and B),and three genotypes( AA,AB,and BB) were observed; loci H1,H2 and H3 formed six diplotypes( D1,D2,D3,D4,D5 and D6). According to the correlations between different genotypes and various growth traits,the body weight and total length of largemouth bass individuals with genotype BB were significantly higher than those of individuals with genotype AB( P < 0. 05); the body weight and total length of largemouth bass individuals with diplotype D6 were significantly higher than those of individuals with diplotype D4( P < 0. 05). In this study,SNP markers correlated with growth traits were obtained in the 3' non-coding region of HBP gene in largemouth bass,w
Chunlong ZHOUJunjie BAIShengjie LIJiajia FANDongmei MA
Pituitary adenylate cyclase activating polypeptide(PACAP) has a wide range of biological functions. We cloned the full-length c DNAs encoding PACAP and PACAP-related peptide(PRP) from the brain of largemouth bass(Micropterus salmoides) and used real-time quantitative PCR to detect PRP- PACAP m RNA expression. The PRP- PACAP cDNA has two variants expressed via alternative splicing: a long form,which encodes both PRP and PACAP,and a short form,which encodes only PACAP. Sequence analysis results are consistent with a higher conservation of PACAP than PRP peptide sequences. The expression of P ACAP-long and PACAP- short transcripts was highest in the forebrain,followed by the medulla,midbrain,pituitary,stomach,cerebellum,intestine,and kidney; however,these transcripts were either absent or were weakly expressed in the muscle,spleen,gill,heart,fatty tissue,and liver. The level of PACAP-short transcript expression was significantly higher than expression of the long transcript in the forebrain,cerebella,pituitary and intestine,but lower than that of the long transcript in the stomach. P ACAP-long and PACAP-short transcripts were first detected at the blastula stage of embryogenesis,and the level of expression increased markedly between the muscular contraction stage and 3 d post hatch(dph). The expression of PACAP- long and PACAP- short transcripts decreased significantly in the brain following 4 d fasting compared with the control diet group. The down-regulation effect was enhanced as fasting continued. Conversely,expression levels increased significantly after 3d of re-feeding. Our results suggest that PRP- PACAP acts as an important factor in appetite regulation in largemouth bass.
