Project description:Genus Epinephelus (Perciformes, Epinephelidae), commonly known as groupers, are usually difficult in species identification for the lack and/or change of morphological specialization. In this study, molecular cytogenetic analyses were firstly performed to identify the closely related species Epinephelus bruneus and E. moara in this genus. The species-specific differences of both fish species showed in karyotype, chromosomal distribution of nucleolar organizer regions (NORs) and localization of 18S rDNA. The heterochromatin (interstitial C-bands) and distribution pattern of telomere (TTAGGG) n in E. bruneus revealed the chromosomal rearrangements and different karyotypic evolutionary characteristics compared to those in E. moara. The cytogenetic data suggested that the lineages of E. bruneus and E. moara were recently derived within the genus Epinephelus, and E. moara exhibited more plesiomorphic features than E. bruneus. All results confirmed that E. moara, which has long been considered a synonym of E. bruneus, is a distinct species in the family Epinephelidae. In addition, molecular cytogenetic analyses are useful in species differentiation and phylogenetic reconstruction in groupers.
Project description:Cortisol was injected into the protogynous epinephelus coioides to investigate the role of this hormone on sex change. Following injection, we evaluated sex-related gene expression during the processes of cortisol-induced sex change in epinephelus coioides.
Project description:Purpose: Next-generation sequencing (NGS) has revolutionized analysis of the immune response to V. alginolyticus in Epinephelus coioides larvae, we used high-throughput deep sequencing technology to study the effect of infection on gene expression. Methods: Epinephelus coioides larvae (30-days-old) were injected with V. alginolyticus , and fish were sacrificed at 24 h after infection. Ten wild-type Epinephelus coioides larvae were used to build an EST library for transcriptome analysis. The library products were prepared for sequencing analysis using an Illumina HiSeq™ 2000. Raw data were saved as fastq files. The following were removed: reads with adaptors, reads in which over 10% bases were unknown, and low quality reads (i.e., the percentage of bases of quality value ≤ 5 exceeds 50% in the read). Clean reads were mapped to reference sequences using SOAP aligner/soap2 . The randomness of RNA fragmentation was used to construct the library, and the numbers of reads mapped to the reference sequence were calculated. The RPKM method (Reads Per kb per Million reads) was used to calculate gene expression level, and differentially expressed genes (DEGs) Results: A total of 114,851,002 reads were assembled, consisting of 9,687,355,560 nucleotides; these were further assembled into 209,082 contigs with a mean length of 372 bp. Gene ontology (GO) analysis of the transcriptome revealed 12 cellular component subcategories, 16 molecular function subcategories, and 42 biological process subcategories (P value < 0.05). A total of 32664 Epinephelus coioides genes were mapped to the Kyoto Encyclopedia of Genes and Genomes (KEGG); 1504 differentially expressed genes (DEGs) were subsequently identified, in 12 categories (P value < 0.05). Vibrio infection affected the expression of genes involved in complementation, coagulation cascades, pathogen (Staphylococcus aureus) infection, phagosome activity, antigen processing, and the antigen presentation pathway. Conclusions: We conclude that the complement pathway of innate immunity and the hepicidin antimicrobial peptide may play important roles in the defense of Epinephelus coioides larvae against V. alginolyticus, and the immune response may activate at 4h after bacterial infection. These results implicate the complement pathway signal pathway in immunity during V. alginolyticus infection at early developmental stages, enhancing our understanding of the mechanisms underlying the immune response to Vibrio infection in Epinephelus coioides.
Project description:Groupers (Epinephelidae) are ecologically, commercially, and culturally important predatory fishes throughout their global distribution range in tropical, subtropical and occasionally temperate regions. They are key species for modern and ancient fisheries in the Mediterranean which have been heavily overfished in the past century leading to smaller catch sizes, lower CPUE, and decreased biomass. There are four species of grouper native to the Mediterranean within the Epinephelus genus.The abundance and distribution of grouper species prior to the 20th century in the Mediterranean remains poorly known. Using peptide mass fingerprinting, also known as Zooarchaeology by Mass Spectrometry (ZooMS), we investigated if ZooMS is a viable method for identifying intra-genus grouper bones to species level. Due to the lack of publicly available genomic sequences and for validation of ZooMS markers, we reconstructed collagen type I amino acid sequences using LC-MS/MS for four Epinephelus spp. Adequate variation between collagen sequences enabled the production of the best supported phylogenetic tree for Mediterranean Epinephelus spp. to date. We identified 23 previously undescribed ZooMS biomarkers capable of distinguishing groupers to the species level. Our novel biomarkers were applied to a case study of 23 grouper/comber fish bones from the Middle to Late Holocene archaeological site of Kinet Höyük, located along the coast of Iskenderun Bay, Turkey. ZooMS markers enabled species level identification of 19 bones with 18 identified as Epinephelus aeneus and 1 identified as Epinephelus marginatus. Combining ZooMS identifications with catch size reconstructions has revealed that E. aeneus is capable of growing ca. 30 cm larger than previously reported. This abundance and dominance of E. aeneus locally at Kinet Höyük is consistent with E. aeneus being the most prevalent grouper species in Iskenderun Bay today, testifying to several millennia of this species local population persistence despite fishing pressure, habitat degradation, and climatic changes.