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: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: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:Gills of teleost fish represent a vital multifunctional organ; however, they are subjected to environmental stressors, causing gill damage. Gill damage is associated with significant losses in the Atlantic salmon aquaculture industry. Gill disorders due to environmental stressors are exacerbated by global environmental changes, especially with open-net pen aquaculture (as farmed fish lack the ability to escape those events). The local and systemic response to gill damage, concurrent with several environmental insults, are not well investigated. We performed field sampling to collect gill and liver tissue after several environmental insults. Using a 44K salmonid microarray platform, we aimed to compare the transcriptomes of pristine and moderately damaged gill tissue. The gill damage-associated biomarker genes and associated qPCR assays arising from this study will be valuable in future research aimed at developing therapeutic diets to improve farmed salmon gill health.
Project description:The fish gill is a multifunctional organ containing a variety of specialized cells including respiratory chemoreceptors, neuroepithelial cells (NECs). Although the structure, function and development of the gill have been studied extensively, transcriptomic profiling of individual gill cells is lacking. Using the 10x Genomics Chromium technology, we conducted a single transcriptomic study of cells from distal gill filament of ETvmat2:GFP zebrafish, acclimated to 14 days of normoxia and hypoxia. Overall, approximately 13,000 cells were sequenced with an average depth of 27,000 reads per cell. We identified 16 cell clusters in the gill, including NECs, neurons, pavement cells, endothelial cells and mitochondrion-rich cells. NECs were identified through expression of vmat2, encoding vesicular monoamine transporter, and showed highly differential expressions of tph1a, sv2, and mitochondrial proteins implicated in O2 sensing. Differential gene expression analysis showed a shift in transcriptome in NECs following 14 days of acclimation to hypoxia. This study presents a comprehensive cell atlas for the zebrafish gill and provides a framework for future investigations of molecular biology and physiology in gills.