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Pelteobagrus intermedius is a unique freshwater fish native species in the Hainan Island and Guangxi and other water systems of China. In this study, the complete mitochondrial genome sequence of P. intermedius was determined from whole genome Illumina sequencing data. The total length of the mtDNA was 16,532 bp, including 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and a non-coding control region. Phylogenetic analysis suggested that the P. intermedius is closely related to Tachysurus fulvidraco. The results will serve as a helpful reference for further studies on the conservation genetics of genus Pelteobagrus. [ABSTRACT FROM AUTHOR]

A β actin cDNA of Tanichthys albonubes was isolated through the RT-PCR and RACE approach. The cDNA was 1,787-bp in length, including a 1,128-bp CDS, a 95-bp 5′UTR and a 564-bp 3′UTR. Genomic DNA containing the transcription region and 5′-flanking region was cloned based on the β actin cDNA by Genome walker. A 3,000-bp β actin gene promoter was then produced by PCR according to the sequences of the 5′-flanking region and the first intron. This promoter consisted of a 1,800-bp 5′-flanking region, and a 1,200-bp 5′-UTR. 3 transcription elements, CAAT box, CArG motif and TATA box were found in the 5′-flanking region. This promoter was inserted into the vector pDsRed2-1 and microinjected into fertilized eggs of Tanichthys albonubes to prove its transcription activity. The β actin promoter and GH CDS of Tanichthys albonubes were then fused to construct an expression vector pTLA-GH. GH-transgenic Tanichthys albonubes was obtained by microinjection of the pTLA-GH into the fertilized eggs . Fast-growth individuals were observed in the transgenic group and the body weight of the largest individual was 2.1-fold that of the maximum in its non-transgenic siblings in 100 dph. In addition, a co-injection strategy was employed with pTLA-DsRed and pTLA-GH vector and proven to enhance the efficiency of GH-transgenic fish detection. [ABSTRACT FROM AUTHOR]

Seventeen special loci were selected from 77 microsatellite markers to distinguish three varieties of tilapias, including the six differential loci UNH636, UNH117, UNH172, UNH738, UNH878 and UNH896 in Oreochromis aureus; five differential loci UNH913, UNH907, UNH222, UNH980 and UNH880 in O. niloticus; and six differential loci of UNH876, UNH899, UNH853, UNH932, UNH933 and UNH773 in O. mossambicus. Any one of the 17 loci could amplify particular bands to distinguish one tilapia from the other two. The genetic structure of O. aureus, O. niloticus and O. mossambicus stocks and their phylogenetic relationships were also analysed using these 17 loci. In total 142 alleles were detected, and the average number of alleles per locus was 8.35. Additionally, a clustering analysis was performed based on the result of the Popgen32 software package and phylogenetic trees were constructed by MEGA4 using the unweighted pair group method using arithmetic average (UPGMA). The results showed that the mean value of observed heterozygosity was 0.0941, 0.5490 and 0.2588, the mean value of expected heterozygosity was 0.1089, 0.7230 and 0.1965, and the polymorphism information content was 0.0869, 0.7149 and 0.1643, in O. aureus, O. niloticus and O. mossambicus, respectively. The UPGMA tree demonstrated that O. aureus was more closely related to O. mossambicus than to O. niloticus. [ABSTRACT FROM AUTHOR]

Abstract  Lysozymes are key proteins to invertebrates in the innate immune responses against bacterial infections. A lysozyme gene isolated from tiger shrimp, Penaeus monodon, was cloned, sequenced and characterized. The cDNA consists of a signal peptide of 18 amino acids and a mature peptide of 140 amino acids. The lysozyme is presumed to be a chicken-type lysozyme for it possesses two catalytic sites and eight cysteine residues which are highly conserved across species of chicken-type lysozymes. The lysozyme cDNAs of Penaeus semisulcatus, Litopenaeus vannamei, Macrobrachium nipponense and Macrobrachium rosenbergii were also cloned. High similarities existed among shrimp and prawn lysozymes but phylogenetic relationship of shrimps and prawns based on lysozyme molecules did not quite consistent with traditional taxonomic classification. High mRNA expression was detected in hepatopancreas, haemocytes and gill of tiger shrimp. Recombinant lysozyme exhibited potent lytic activities against fish pathogens providing evidence of the involvement of lysozyme in shrimp immunity. [ABSTRACT FROM AUTHOR]

The green sunfish ( Lepomis cyanellus) is a species of freshwater fish in the Centrarchidae family of order Perciformes, which is native to a wide area of North America. This species was introduced into China in 1998 and became one of the economically important freshwater species. In this study, we determined the complete mitochondrial genome sequence of L. cyanellus. The total length of L. cyanellus mitogenome is 16,485 bp, which consists of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 1 control region (D-loop), with the genome organization and gene order being identical to that of the typical vertebrate. The overall base compositions of the heavy strand are 27.5% A, 26.2% T, 29.9% C, and 16.4% G, with an A + T content of 53.7%. The mitochondrial genome of L. cyanellus shared 86.8% sequence identity with that of Lepomis macrochirus. The sequence information presented here will be useful for evolutionary as well as population genetic studied. [ABSTRACT FROM AUTHOR]

Pelteobagrus intermedius is a unique freshwater fish native species in the Hainan Island and Guangxi and other water systems of China. In this study, the complete mitochondrial genome sequence of P. intermedius was determined from whole genome Illumina sequencing data. The total length of the mtDNA was 16,532 bp, including 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and a non-coding control region. Phylogenetic analysis suggested that the P. intermedius is closely related to Tachysurus fulvidraco . The results will serve as a helpful reference for further studies on the conservation genetics of genus Pelteobagrus ., Competing Interests: The authors report that they have no conflicts of interest. The authors alone are responsible for the content and writing of the paper., (© 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)

A beta actin cDNA of Tanichthys albonubes was isolated through the RT-PCR and RACE approach. The cDNA was 1,787-bp in length, including a 1,128-bp CDS, a 95-bp 5'UTR and a 564-bp 3'UTR. Genomic DNA containing the transcription region and 5'-flanking region was cloned based on the beta actin cDNA by Genome walker. A 3,000-bp beta actin gene promoter was then produced by PCR according to the sequences of the 5'-flanking region and the first intron. This promoter consisted of a 1,800-bp 5'-flanking region, and a 1,200-bp 5'-UTR. 3 transcription elements, CAAT box, CArG motif and TATA box were found in the 5'-flanking region. This promoter was inserted into the vector pDsRed2-1 and microinjected into fertilized eggs of Tanichthys albonubes to prove its transcription activity. The beta actin promoter and GH CDS of Tanichthys albonubes were then fused to construct an expression vector pTLA-GH. GH-transgenic Tanichthys albonubes was obtained by microinjection of the pTLA-GH into the fertilized eggs. Fast-growth individuals were observed in the transgenic group and the body weight of the largest individual was 2.1-fold that of the maximum in its non-transgenic siblings in 100 dph. In addition, a co-injection strategy was employed with pTLA-DsRed and pTLA-GH vector and proven to enhance the efficiency of GH-transgenic fish detection.

Forty microsatellite loci were selected to amplify the genomic DNA of cultured stock of largemouth bass (Micropterus salmoides L.) in China. Genotypic differences of these microsatellites loci were analyzed using 2-test between the maximal weight group and minimal weight group. Sixteen microsatellites showing significantly difference (P<0.1) were used in genotyping 121 individuals, and the associations between their genotypes and growth traits were examined. Microsatellite loci of JZL60, JZL67, JZL72, JZL124, MiSaTPW76, MiSaTPW117 and MiSaTPW173 were significantly associated with body weight, body length, and body height (P < 0.05 or P < 0.01). The most favorable genotypes for growth traits were AA at JZL60, BB at JZL67, AC at JZL72, BB at MiSaTPW76 and BC at MiSaTPW117. In addition, a total of 47 alleles for the 16 loci were detected (2 approximately 5 alleles for each locus). The average effective number of alleles (Ae), observed heterozygosity (Ho), expected heterozygosity (He) and mean polymorphic information content (PIC) was 2.938, 0.515, 0.500 and 0.445, respectively, both of which indicated that the population genetic diversity was medium.

Cystatin, which widely distributed in both tissues and body fluids of animal and plant, was a superfamily of cysteine proteinase inhibitors. It could form activity-inhibitor complexes with cysteine proteinases to inhibit the hydrolytic activity of proteinases. Cystatin played important roles not only in the inhibition of the proteolytic degradation of fish muscle, but also in biological defense systems against invaders. To explore the functions of fish cystatin and the potential values in fish disease prevention and cure, as well as seafood processing, the recombinant yeast strains which could express Chinese sturgeon cystatin were constructed. First, the cystatin cDNA of Chinese sturgeon, which had been PCR modified, was subcloned into yeast integrated vector pPICZaA. After extracted and purified, the recombinant plasmids were linearized by Sac I. The yeast Pichia pastoris GS115 strain was transformed by use of the Lithium Chloride transformation method, and the recombinant cystatin yeast strains got. After 0.5% methanol induction, SDS-PAGE analysis of the culture supernatant indicated that the yield of recombinant cystatin was about 215mg x L(-1) with the percentage about 73.6%. The recombinant cystatin was purified through Q-Sepharose anion-exchange chromatography, and the purity reached about 94.2%. The inhibitory activity of recombinant cystatin was measured by inhibiting the proteinase activity of papain. The results showed that about 1 microg recombinant cystatin could inhibit the activity of 15 microg papain. Heat stability assay results showed that there was a decrease in inhibitory activity of cystatin with the increasing of temperature. When solution of recombinant cystatin was kept at 70 degrees C for 5min, the inhibitory activity reduced fast. While the recombinant cystatin was heated to 90 degrees C for 5min, the inhibitory activity of recombinant cystatin was undetected. The inhibitory activity for recombinant Chinese sturgeon cystatin was higher than that of CPI (cysteine proteinase inhibitor) from seeds of corn, that about 1 microg purified CIP could inhibited the activity of 0.278 microg papain. But the heat stability of recombinant cystatin is lower than that of the corn CPI. The expression level and the activity of recombinant cystatin from yeast Pichia pastoris were higher than those from E. coli. Moreover, recombinant cystatin from Pichia pastoris was easier to separate and purify. This paper reported that recombinant fish cystatin was produced in a highly efficient expression system based on the methylotrophic yeast, further work will focus on the function of recombinant Chinese sturgeon cystatin to resist fish disease and explore the value of cystatin as a food additive to inhibit cysteine proteinases during surimi processing.