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: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: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: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: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. mRNA from lesion and non-lesion gill tissue was amplified and labeled. Six biological and two technical replicates were utilised to hybridise to 12 arrays using amplified RNA from AGD-affected lesion gill tissue with AGD-naive fish as a control. Four biological and two technical replicates were utilised to hybridise to 8 arrays using amplified RNA from AGD-affected lesion gill tissue with non-lesion tissue from the same gill arch as a control. The assignment of microarrays to treatment groups for hybridization was randomised by using a random number generator.
Project description:The salmon gill poxvirus (SGPV) is a large DNA virus that infects gill epithelial cells in Atlantic salmon and is associated with acute high mortality disease outbreaks in aquaculture. The pathological effects of SGPV infection include gill epithelial apoptosis in the acute phase of the disease and hyperplasia of gill epithelial cells in surviving fish, causing damage to the gill respiratory surface. Transcriptome responses to virus were assessed in gills at different stages of disease
Project description:The experiment focused on the transcriptomic changes associated with gill inflammation in sea farmed Atlantic salmon (Salmo salar). To ensure the multifactorial aspect of gill inflammation, fish were sampled at three marine production sites (A on Isle of Mull, B in Shetland and C in Shetland) between October 2017 and March 2018. All fish were of strain Fanad and originated from the same egg fertilisation batch. They were reared in different hatcheries (Couldoran, Pettigo-Damph and Knock-Frisa for sites A, B and C, respectively) for one year and entered the sea in spring 2017. The resultant gill tissues (44 samples in total with 1 gill sample per fish) were first scored for proliferative gill disease (PGD), using gross morphology PGD scores from 0 with no visual pathology to 5 with severe visual pathology, and then subjected to RNA-seq and histopathological (microscopic) examination. One RNA-seq sample (fish 95) was identified as an outlier and removed from the subsequent analysis. As a result, the analysis aiming to integrate gill transcriptome, gross morphology and histopathology was performed on 43 gill samples, classified either as PGD score 1 (n = 26) or PGD score 3 (n = 17). In total, 20 gill samples originated from site A (10 with PGD1 and 10 with PGD 3, 10 samples from site B (7 with PGD1 and 3 with PGD 3) and 13 samples from site C (9 with PGD1 and 4 with PGD 3).
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:Exposure to environmental contaminants like nonylphenol can disrupt smolt development and may be a contributing factor in salmon population declines. We used GRASP 16K cDNA microarrays to identify genes that are differentially expressed in the liver, gill, hypothalamus, pituitary, and olfactory rosettes of Atlantic salmon smolts treated with nonylphenol compared to control smolts. Nonylphenol treatment was confirmed using physiological assays: nonylphenol-treatment significantly decreased gill Na+,K+-ATPase activity and plasma cortisol and T3 levels. Microarray analyses were used to compare expression in nonylphenol-injected fish with expression in vehicle-injected fish: eight arrays each for liver, gill, olfactory rosettes, hypothalamus, and pituitary tissues. Total RNA was isolated from the tissues of eight nonylphenol-injected fish (six males and two females) and eight vehicle-injected fish (two males and six females) and reverse transcribed separately (not pooled); each slide represents a biological replicate. For each tissue, the eight arrays were balanced for dye: nonylphenol-injected fish were labeled with Alexa Fluor 555 and vehicle-injected fish were labeled with Alexa Fluor 647 on four slides, nonylphenol-injected fish were labeled with Alexa Fluor 647 and vehicle-injected fish were labeled with Alexa Fluor 555 on four slides. Liver, gill, hypothalamus, pituitary, and olfactory rosette tissues were analyzed separately.