Project description:Whereas the gill chambers of extant jawless vertebrates (lampreys and hagfish) open directly into the environment, jawed vertebrates have evolved skeletal appendages that promote the unidirectional flow of oxygenated water over the gills. A major anatomical difference between the two jawed vertebrate lineages is the presence of a single operculum covering a large common gill cavity in bony fishes versus separate covers for each gill chamber in cartilaginous fishes. Here we find that these divergent gill cover patterns correlate with the pharyngeal arch expression of Pou3f3 orthologs, and we identify a deeply conserved Pou3f3 arch enhancer that is present in nearly all jawed vertebrates but undetectable in lampreys. Despite only minor sequence differences, bony fish and cartilaginous fish versions of this enhancer are sufficient to drive the respective single versus multiple gill arch expression. In zebrafish, loss of Pou3f3 gene function or its conserved enhancer disrupts gill cover formation. Conversely, forced expression of Pou3f3b in the gill arches generates ectopic skeletal elements reminiscent of the multiple gill covers of cartilaginous fish. Emergence and modification of this ancient Pou3f3 enhancer may thus have contributed to the acquisition and diversification of gill covers during early gnathostome evolution.
Project description:Dissolved oxygen (DO) is the basis of fish survival, and proper DO level is an important condition to ensure the normal growth of fish. Hypoxic environment is prone to disturb the normal breathing and metabolism of fish, which in turn affects their growth and survival. Gill tissue is the respiratory organs of fish and is in direct contact with the external environment. However, there are few reports on the molecular regulatory mechanism of genetically improved farmed tilapia (GIFT, Oreochromis niloticus) gill tissues in response to hypoxia. Here, we first examine the hypoxia-induced damage of gill tissue by hematoxylin-eosin staining, and then constructed miRNA and mRNA libraries of GIFT gill tissue at 96h of hypoxia stress by a high-throughput sequencing technology, each library has three biological replicates. Gill lamellae of GIFT showed capillary rupture and red blood cell enlargement and overflow under hypoxia stress. Transcription sequencing results showed that the clean reads of miRNA libraries were 9,627,953-13,544,660; the clean reads of mRNA libraries were 43,817,776-53,130,102. Based on the miRNA-mRNA pairs screening principles and mRNA sequencing results, we selected and verified seven differentially expressed miRNAs and their potential target genes. The sequencing results were consistent with the qRT-PCR validation results. These selected miRNA-mRNA pairs are mainly concentrated in the signaling pathways of immune response and metabolic regulation. This study provides new insights into the mechanisms of fish adaptation under hypoxic stress.
Project description:Dissolved oxygen (DO) is the basis of fish survival, and proper DO level is an important condition to ensure the normal growth of fish. Hypoxic environment is prone to disturb the normal breathing and metabolism of fish, which in turn affects their growth and survival. Gill tissue is the respiratory organs of fish and is in direct contact with the external environment. However, there are few reports on the molecular regulatory mechanism of genetically improved farmed tilapia (GIFT, Oreochromis niloticus) gill tissues in response to hypoxia. Here, we first examine the hypoxia-induced damage of gill tissue by hematoxylin-eosin staining, and then constructed miRNA and mRNA libraries of GIFT gill tissue at 96h of hypoxia stress by a high-throughput sequencing technology, each library has three biological replicates. Gill lamellae of GIFT showed capillary rupture and red blood cell enlargement and overflow under hypoxia stress. Transcription sequencing results showed that the clean reads of miRNA libraries were 9,627,953-13,544,660; the clean reads of mRNA libraries were 43,817,776-53,130,102. Based on the miRNA-mRNA pairs screening principles and mRNA sequencing results, we selected and verified seven differentially expressed miRNAs and their potential target genes. The sequencing results were consistent with the qRT-PCR validation results. These selected miRNA-mRNA pairs are mainly concentrated in the signaling pathways of immune response and metabolic regulation. This study provides new insights into the mechanisms of fish adaptation under hypoxic stress.
Project description:Amoebic gill disease (AGD) is an ectoparasitic condition of some farm-reared marine fish and is caused by Neoparamoeba perurans. Tanks housing Atlantic salmon (Salmo salar) were inoculated with Neoparamoeba perurans and fish were sampled at 36 days postinoculation (pi.). AGD-affected gill tissue was dissected from N. perurans infected fish, and a DNA microarray was used to compare global gene expression against tissues from AGD-naive fish. To determine whether the changes in gene expression were restricted to AGD-lesions, lesion tissue from AGD-affected fish was also compared with non-lesion gill tissue dissected from the same gill arch. Samples were assessed using a DNA microarray. Keywords: comparative gene expression, parasite-induced lesion, Neoparamoeba perurans, amoebic gill disease
Project description:Using RNAseq of small RNA libraries isolated from the gill tissue of the Antarctic fish Trematomus bernacchii we have characterized the termal sensitivity of miRNA homologues in these highly stenothermic fish.
Project description:The aim of this sequencing experiment was to make available tissue expression panels for selected fish species for comparative expression studies between the species. Tissue samples were collected for zebrafish (Danio rerio), medaka (Oryzias latipes), and rainbow trout (Oncorhynchus mykiss). Tissue types included liver, skin, muscle, heart, gut, gill, eye, brain for all three species, with additionally pyloric caeca, kidney, head kidney, and spleen for rainbow trout. Only liver samples were taken in replicate of four or three for rainbow trout. All fish were raised under standard rearing conditions for the species. Total RNA was extracted from the tissue samples and paired‐end sequencing of sample libraries was completed on an Illumina HiSeq 2500 with 125‐bp reads. Processed count tables per species as raw counts, FPKM, or TPM, were generated from read alignment to the Ensembl genomes of the respective species using STAR and gene level counting using RSEM and Ensembl gene annotation.