Pengze Crucian Carp Research Articles

Molecular cloning and characterization of amh, dax1 and cyp19a1a genes and their response to 17α-methyltestosterone in Pengze crucian carp

The proteins encoded by amh, dax1 and cyp19a1a play important roles in gonad differentiation. Their functions have been far less studied in teleosts. In this study, the full-length cDNAs of amh, dax1 and cyp19a1a were cloned and characterized in a triploid gynogenic fish, the Pengze crucian carp. Their expression profilings in juvenile development, adult tissues and juveniles exposed to 100ng/L 17α-methyltestosterone (MT) were investigated. Results showed that their putative proteins shared high identities to their counterparts in cyprinid fish species, respectively. The tissue distribution results indicated that amh and cyp19a1a were predominantly expressed in the ovary and dax1 was dominantly expressed in the liver. Gene profiling in the developmental stages showed that all the three target genes had a consistent highest expression at 48days post hatching (dph). The period of 48dph appeared to be a key time during the process of the gonad development of Pengze crucian carp. 100ng/L MT significantly increased the mRNA expression of amh at 2- and 4-week exposures and enhanced dax1 and cyp19a1a at 6-week exposure. The present study indicated that MT could influence the gonad development in Pengze crucian carp by disturbing sex-differentiation associated gene expression. Furthermore, the present study will be of great significance to broaden the understanding of molecular mechanisms of the physiological processes of reproduction in fish.

Molecular cloning and characterization of cat, gpx1 and Cu/Zn-sod genes in pengze crucian carp (Carassius auratus var. Pengze) and antioxidant enzyme modulation induced by hexavalent chromium in juveniles

Hexavalent chromium (Cr6+) is a common pollutant transient metal with high toxicity in the environment. The toxicological effects partly result from oxidative damage due to the production of excessive reactive oxygen species (ROS) in the reductive process of Cr6+. To explore the influence of ROS induced directly by Cr6+ on the oxidative stress generation and antioxidant system, the full length cDNAs of antioxidant-related genes cat, gpx1 and Cu/Zn-sod were successfully acquired from pengze crucian carp first and analyzed. Furthermore, the mRNA expression of the antioxidant genes encompassing catalase (cat), copper/zinc superoxide dismutase (Cu/Zn-sod) and glutathione peroxidase (gpx1), antioxidant enzyme activities of CAT, SOD, and GPx and total protein content were further studied in the gill, intestine and liver of pengze crucian carp (Carassius auratus var. Pengze) juveniles upon acute exposure to Cr6+ at concentrations of 0.1, 1.0, 10 and 100mg/L for 4days. Differential significant changes of the antioxidant enzymes and gene expression were observed in different tissues. The findings contribute to better understanding the antioxidant mechanisms induced by Cr6+ and selecting the organic-specific sensitive biomarkers to monitor the safety of the aquatic ecosystem.

Saprolegnia Pathogen from Pengze Crucian Carp (Carassius auratus var. Pengze) Eggs and its Control with Traditional Chinese Herb

In the present study, a pathogenic strain, JL, was isolated from Pengze crucian carp (Carassius auratus) eggs suffering from saprolegniosis. It was initially determined as Saprolegnia sp. strain JL. Saprolegnia species have been implicated for significant fungal contamination, involving both living and dead fish and their eggs. A phylogenetic tree was constructed using the maximum parsimony method. The tree shows that the JL strain was closely related to Saprolegnia parasitica isolate SAP171, isolated from Salmo trutta suffering from saprolegniasis in Laukaa, Finland. The minimum inhibitory concentration (MIC) of 20 Chinese herbs was screened. Pseudolarix kaempferi Gord. (Pinaceae) was the most effective in inhibiting growth of the bacteria and was chosen for further trial. Significant protective efficacy of 52.63% and 73.68% was obtained against the JL strain in Pengze crucian carp eggs at P. kaempferi concentrations of 12.5 mg/ml and 25.0 mg/ml, respectively.

English

Invariant chain (Ii) plays an important role in MHC class II molecules assembly and exogenous peptide presentation in vertebrates. Although mammalian Ii has been extensively studied, less attention is paid to its fish counterpart. In this study, in order to understand the structure and biological function of Chinese Pengze crucian carp (Carassius auratus) Ii, we first cloned Ii gene (Caau-Ii) using RT PCR and rapid amplification of cDNA end techniques. Firstly, a conserved DNA fragment was amplified using a pair of degenerate primers from fish’s head kidney and spleen total RNA. Then specific primers for RACE were designed to amplify the 5' and 3' ends of Caau-Ii. Finally, the full-length cDNA of Caau-Ii was amplified, sequenced and analyzed and the results showed that it was 1063 bp in length and contained an open reading frame of 696 bp encoding Caau-Ii precursor protein. Amino acid sequence alignment showed that (1) Caau-Ii had high homology with that of carp and zebrafish (identify >70%) and low homology with mammalian Ii (30% < identity <40%); (2) Caau-Ii had similar domains seen in mammalian Ii, including transmembrane domain, CLIP (class II-associated Ii-derived peptide) and TRIM (trimerization) domain.   Key words: Invariant chain, Carassius auratus, RACE, cloning, domain analysis.    

Molecular cloning and tissue distribution of lipoprotein lipase full-length cDNA from Pengze crucian carp (Carassius auratus var. Pengze)

A full-length cDNA coding lipoprotein lipase (LPL) was cloned from liver of adult Pengze crucian carp (Carassius auratus var. Pengze) by RT-PCR and rapid amplification of cDNA ends (RACE) approaches. The cDNA obtained was 1877 bp long with a 1524 bp open reading frame (ORF) encoding 507 amino acids, including a putative signal peptide of 23 amino acids long. The deduced amino acid sequence has a high similarity and shows similar structural features to LPL of other species. The LPL protein has a calculated molecular mass of 57.7 kDa and isolectric point of 7.85. Tissue distribution of LPL mRNA in mesenteric adipose tissue, liver, heart, head kidney and white muscle of adult Pengze crucian carp was analyzed by semi-quantitative RT-PCR method using beta-actin gene as internal control, the result showed that this gene was ubiquitously expressed in all tissues tested with the highest abundance in mesenteric adipose tissue, following in head kidney and liver, and the lowest expression was found in heart and white muscle.

Karyotypic analysis of the multiple tetraploid allogynogenetic pengze crucian carp and its parents

Pengze crucian carp ( Carassius auratus of pengze), just like silver crucian carp, is known to be a gynogenetic crucian carp. It is one of the most popular cultured fishes in China. The offspring developed from pengze crucian carp eggs activated by heterologous sperm shows obvious allogynogenetic biological effects in growth and fertilization rate, although the offspring is almost the same in morphology as the maternal pengze crucian carp. Recently, a multiple tetraploid form, which showed obvious morphological changes compared with the normal allogynogenetic offspring, was found in the offspring developed from pengze crucian carp eggs stimulated by sea carp ( Cyprinus acutidorsalis Wang) sperm. In this paper, the chromosome number and karyotype of the multiple tetraploid form and its parents were analyzed, using chromosomes of kidney cell-PHA culture in vivo prepared by flame-drying technique. The paternal sea carp had 2 n=100 diploid chromosomes and the karyotype of 28 metacentric, 24 submetacentric, 26 subtelocentric and 22 telocentric, NF=152. The maternal pengze crucian carp had 156 chromosomes in its karyotype, with 42 metacentric, 36 submetacentric, 39 subtelocentric, 33 telocentric, and 6 supernumerary microchromosomes. The karyotype of the multiple tetraploid allogynogenetic pengze crucian carp contained 206 chromosomes, with 56 metacentric, 48 submetacentric, 44 subtelocentric, 52 telocentric, and 6 supernumerary microchromosomes. Both the multiple tetraploid form and its maternal parent had six supernumerary microchromosomes. The results indicated that the chromosomes of the multiple tetraploid allogynogenetic pengze crucian carp consist of the whole maternal chromosome set and a haploid paternal chromosome set, which suggests that a few of the gynogenetic pengze crucian carp eggs have the gonochoristic reproductive ability to integrate with heterologous sperm nuclei.