Project description:Individual stress coping style has profound effects on how animals respond to environmental change, and individuals within a population strikingly differ in how gene expression shifts in response to challenge. This study used a wild type Zebrafish (Danio rerio) population to: 1) identify and screen for individual coping style using a screening protocol for risk taking in groups and 2) do global transcriptomics of brains from proactive, reactive or randomly chosen individuals (n=10/group) under control conditions. Results show that within our population proactive and reactive individual coping styles can be accurately identified and may represent 10-30% of individuals within the population. Microarray data analyses identify fundamental differences between the three different groups where variance in gene expression values are reduced by using coping style as an explanatory variable. Furthermore, significant differences in mRNAs and related biological processes suggest that even under identical environmental conditions the molecular mechanisms that underpin physiological processes are very different between proactive and reactive individuals within a population. Experimental tank was an 18 litre glass aquarium (dimensions (LxWxH): 40 X 25 X 20cm) lined on three sides with white paper; the front wall was not covered to allow the observer to record the behaviour and divided at 1/3 of his length with a black PVC screen with a 3cm diameter hole in the middle. All the tank surfaces around this third area of the tank were covered with dark paper and closed on the upper part with a removable lid to provide a shelter for the animals. The hole was covered with the same PVC plastic material and removed once the screening started to allow the fish enter the novel environment. Food was not supplied the day before to ensure that during the test the fish were hungry and they had to make the decision to leave a safe area in order to forage. Boldness was measured as the time taken by individual fish to leave a group from a safe, darkened area. It hence represents the willingness of a fish to explore a new, potentially dangerous environment, or boldness. Tests were conducted with groups of 9 randomly-selected fish from stocking tanks. Fish were familiar to each other in the sense that they were previously held in the same stocking tank. Test started with a 10 min. habituation period in the sheltered area with the hole closed with a PVC screen and the top of the sheltered area of the tank also covered to provide a complete quiet place. Then the lid covering the hole was gently removed. Either the first 3 fish to exit the shelter or fish with latency times inferior to 10 minutes were considered bold fish and were removed gently with a fish net from the test tank and placed apart in another tank. Latency times of emergency from the sheltered area were recorded individually. Next 3 animals to emerge before 15 minutes were considered intermediate and also removed gently. At the end of this last 15 minutes, animals that still remained inside the sheltered area were considered shy. Intermediates were discarded and fish selected for different coping strategies where placed in different tanks for posterior molecular analysis. Selected animals were killed by an overdose of MS-22 and the brains were sampled. Individual tissue samples were homogenized into 0.3 ml of Tri-Reagent and stored at -80C for further molecular analysis.

Project description:With the aim of shedding light on the protection conferred by the DNA vaccines based in the G glycoprotein of viral haemorrhagic septicaemia virus (VHSV) in turbot (Scophthalmus maximus) we have used a specific microarray highly enriched in antiviral sequences to carry out the transcriptomic study associated to VHSV DNA vaccination/infection. The differential gene expression pattern in response to empty plasmid (pMCV1.4) and DNA vaccine (pMCV1.4-G860) intramuscular administration with regard to non-stimulated turbot was analyzed in head kidney at 8, 24 and 72 hours post-vaccination. Moreover, the effect of VHSV infection one month after immunization was also analyzed in vaccinated and non-vaccinated fish at the same time points. A total number of 204 juvenile turbot were divided into 3 groups, two of them containing 72 fish and the last one 60 fish. Turbot were anaesthetized by immersion in 50 mg/ml buffered tricaine methanesulfonate (MS-222; Sigma) and then, fish from the first two groups were intramuscularly (i.m.) injected with 50 µl of PBS containing 2 µg of pMCV1.4 or pMCV1.4-G860. Turbot from the last batch were i.m. inoculated with 50 µl of PBS. At 8, 24 and 72 h after injection, 12 fish were removed from the first two tanks and, at 8 h after PBS inoculation, other 12 fish were taken from the last tank. These turbot were sacrificed by anaesthetic overdose and the head kidney was removed. Equal amounts of tissue from three fish belonging to the same tank and sampling point were pooled, obtaining 4 biological replicates for each treatment and time point (3 turbot/replicate). The remaining fish (36 in the plasmid-injected groups and 48 in the PBS-inoculated tank) were maintained during one month and then, 12 fish from the PBS injected group were separated to another tank. This new group of fish was intraperitoneally (i.p.) injected with 50 µl of MEM + penicillin and streptomycin + 2% FBS (PBS - MEM group), whereas the other turbot were i.p. infected with a dose of VHSV860 of 5 x 105 TCID50/fish (pMCV1.4 - VHSV and pMCV1.4-G860 - VHSV groups). At 8, 24 and 72 hours after infection, 12 fish were removed from the VHSV-infected tanks, and at 8 h after MEM injection the 12 fish were taken from the non-infected tank. The fish were sacrificed by anaesthetic overdose and the head kidney was removed. Equal amounts of tissue from three fish belonging to the same tank and sampling point were pooled, obtaining 4 biological replicates for treatment and time point (3 turbot/replicate)

Project description:Arctic charr is an especially attractive aquaculture species given that it features the desirable tissue traits of other salmonids, but can be bred and grown at inland freshwater tank farms year round. It is therefore of interest to develop upper temperature tolerant (UTT) strains of Arctic charr to increase the robustness of the species in the face of climate change, as well as to enable production in more southern regions. We conducted an acute temperature trial to identify temperature tolerant and intolerant Arctic charr individuals. Specifically, approximately 200 fish were transferred to an experimental tank (diameter: 1.86 m, depth 50 cm) and left to acclimate for 48 h at ambient temperature. After acclimation, 10 fish were removed to act as a control group, then water that had been diverted through a heat exchanger was added to the flow-through system to increase the water temperature in the tank by 6°C/h until it reached 22°C, then 0.5°C every 30 min until the water reached 25°C, the observed lethal temperature for these fish. When the water temperature reached 25°C, the temperature was held constant and the fish were closely monitored for signs of stress. The first and last 10 individuals to show loss of balance were quickly removed from the tank for sampling, thus representing the 5% least and most temperature tolerant fish, respectively. A reference design microarray study was then performed with the cGRASP 32K microarray using six samples from each group (Intolerant, Tolerant, Control) to identify genes differentially expressed between groups. The results of this study will feed into an ongoing Arctic charr marker-assisted selection based broodstock development program, and may contribute to population-based conservation initiatives for salmonids in general. 18 microarray slides representing 6 individuals from 3 treatment groups (Intolerant, Tolerant and Control). One test cDNA labeled with cy5 and the common reference aRNA labeled with Cy3 was hybridized to each slide Reference design: 18 slides (6 x Tolerant fish, 6x Intolerant fish, 6x Control fish) were used.

Dataset Information

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets