Oncorhynchus mykiss liver cells: Small vs. Large fish
ABSTRACT: Transcriptional profiling of rainbow trout liver cells comparing liver cells from small fish with liver cells from large fish at two time periods. Two-condition experiment, small vs. large-fish liver cells. Sept. and Dec. spawning fish. Biological replicates: 4 small replicates, 4 large replicates for each time period.
Project description:Transcriptional profiling of rainbow trout muscle cells comparing muscle cells from small fish with muscle cells from large fish at two time periods. Two-condition experiment, small vs. large-fish muscle cells. Sept. and Dec. spawning fish. Biological replicates: 4 small replicates, 4 large replicates for each time period.
Project description:Transcriptional profiling of rainbow trout liver and muscle cells comparing small fish with large fish within a population of neomale offspring. Small vs. large-fish liver and muscle cells from neomale offspring. Biological replicates: 4 small replicates, 4 large replicates.
Project description:This SuperSeries is composed of the SubSeries listed below. Growth in fishes is a complex trait, controlled by both genetic and environmental factors, that impacts many components of fitness. Gene expression studies may lead to the identification of candidate genes for growth and microarrays offer the opportunity to examine the expression of thousands of genes simultaneously. Gene expression differences in the liver and white muscle were examined in normally growing, 15 month-old, large and small size-selected rainbow trout (Oncorhynchus mykiss) derived from two different seasonal spawning groups (Sept. and Dec.). Examination of the gene expression differences in both liver and white muscle tissue allowed us to assess the seasonal influences upon gene expression patterns that occur in this species, and facilitated the identification of genes that may possess similar expression patterns regardless of seasonal effects. The analysis of global gene expression in large and small fish reared under standard conditions provides an understanding of typical growth patterns that may be observed in this species. The identification of candidate genes by this study may provide insight into the mechanisms of growth in fishes and may help to identify candidate genes for growth.
Project description:BACKGROUND: Growth in fishes is regulated via many environmental and physiological factors and is shaped by the genetic background of each individual. Previous microarray studies of salmonid growth have examined fish experiencing either muscle wastage or accelerated growth patterns following refeeding, or the influence of growth hormone and transgenesis. This study determines the gene expression profiles of genetically unmanipulated large and small fish from a domesticated salmonid strain reared on a typical feeding regime. Gene expression profiles of white muscle and liver from rainbow trout (Oncorhynchus mykiss) from two seasonal spawning groups (September and December lots) within a single strain were examined when the fish were 15 months of age to assess the influence of season (late fall vs. onset of spring) and body size (large vs. small). RESULTS: Although IGFBP1 gene expression was up-regulated in the livers of small fish in both seasonal lots, few expression differences were detected in the liver overall. Faster growing Dec. fish showed a greater number of differences in white muscle expression compared to Sept. fish. Significant differences in the GO Generic Level 3 categories 'response to external stimulus', 'establishment of localization', and 'response to stress' were detected in white muscle tissue between large and small fish. Larger fish showed up-regulation of cytoskeletal component genes while many genes related to myofibril components of muscle tissue were up-regulated in small fish. Most of the genes up-regulated in large fish within the 'response to stress' category are involved in immunity while in small fish most of these gene functions are related to apoptosis. CONCLUSIONS: A higher proportion of genes in white muscle compared to liver showed similar patterns of up- or down-regulation within the same size class across seasons supporting their utility as biomarkers for growth in rainbow trout. Differences between large and small Sept. fish in the 'response to stress' and 'response to external stimulus' categories for white muscle tissue, suggests that smaller fish have a greater inability to handle stress compared to the large fish. Sampling season had a significant impact on the expression of genes related to the growth process in rainbow trout.
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.
Project description:Although studies have established that exogenous growth hormone (GH) treatment stimulates growth in fish, its effects on target tissue gene expression are not well characterized. We assessed the effects Posilac® (Monsanto Co., St. Louis, MO), a recombinant bovine somatotropin, on tissue transcript levels. Transcript abundance was measure in liver and muscle using the GRASP 16 K cDNA microarray. A selection of the genes identified as altered with the microarray, and also transcripts for insulin-like growth factors, growth hormone receptors (GHR) and myostatins were measured by realtime PCR in the liver, muscle, brain, kidney, intestine, stomach, gill and heart. In general, transcripts identified as differentially regulated in the muscle on the microarray showed similar direction of expression in the other non-hepatic tissues. Rainbow trout were selected from two high growth rate and two low growth rate families. A total of 113 and 67 transcripts were identified by microarray as differentially expressed with GH treatment across growth rate for muscle and liver respectively. The largest proportion of the transcripts represented novel transcripts, followed by immune and metabolism related genes. The immune related genes were primarily modulated in the liver and indicate activation of a non-specific immune response. The metabolic genes include lipid metabolism, oxidative phosphorylation and one carbon metabolism pathway transcripts. Most notable among the growth axis genes measured by realtime PCR were increases in GHR1 and-2 transcript in liver and muscle. Our results indicate that short-term GH treatment activates the immune system, shifts the metabolic sectors and modulates growth regulating genes. Keywords: Growth Hormone Injection Muscle and Liver Gene Expression Rainbow trout (hatched March 2005) selected for extreme growth rate were obtained from NCCCWA brood stock. Families were selected based on body weight at 7 months of age and thermal growth coefficient for the final month of growth. The two high growth families used in the study were in the top 2% in terms of growth rate, and the low growth families were in the lowest 10% for growth rate. Fish acclimated to the new tanks for two weeks prior to initiation of the treatments. Fish from each family were randomly selected to receive one of three treatments: 1) Posilac® injection (120 mg/kg BW, n = 4 per family); 2) vehicle injection (n = 4 per family); or 3) untouched controls (n = 2 per family). We had determined there was no effect to growth or the GH/IGF-I axis in the vehicle treated fish, and therefore, all of the microarray hybridizations were made between the GH and vehicle injected groups. This study included a total of 16 two-channel arrays designed for the direct comparison of GH treatment levels. That is, for each of the four groups, 1) High Growth Rate Liver; 2) Low Growth Rate Liver; 3) High Growth Rate Muscle; and 4) Low Growth Rate Muscle, four slide were hybridizes using individual RNA samples from individual fish. RNA isolation from each tissue/organ sample was handled separately (without pooling) with the purpose of using biological replications. We hybridized two slides with the GH cDNA labeled with Alexa 555 and vehicle cDNA labeled with Alexa 647; and two slides, using unique RNA samples, for the with GH cDNA labeled with Alexa 647 and tissue from the vehicle injected group labeled with Alexa 647 within each tissue and growth rate. Sixteen slides were used in the current study representing 32 individual tissue samples, meaning a total of four biological replicates for each treatment group.
Project description:Atrazine (ATZ) and nonylphenol (NP) are commonly identified contaminants in aquatic habitats; however, relatively few studies have considered the impact of these endocrine disrupters on immune function. This study examined the immunotoxicological effects of ATZ and NP at multiple levels of biological organization. Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to a solvent control (0.00625 % v/v anhydrous ethanol), 59 µg/L ATZ, 555 µg/L ATZ, 2.3 µg/L NP or 18 µg/L NP (measured concentrations) for 4 d. At the end of exposure, fish were assessed for general health indicators (liver somatic index (LSI), spleen somatic index (SSI), hematocrit), biochemical endpoints (plasma cortisol concentrations, lysozyme activity, and protein content), a cellular endpoint (blood leukocyte differential counts), and an integrated immune response at the organism level (host resistance challenge with Listonella anguillarum). Additionally, liver gene expression was assessed using a salmonid microarray (cGRASP, 32K version 1) for fish exposed to the (solvent) control, high ATZ (555 µg/L) and high NP (18 µg/L) treatments. Fish exposed to the high ATZ concentration exhibited elevated plasma cortisol, a decrease in SSI, and decreased lymphocytes and increased monocytes in peripheral blood, with suppression of early immune system processes apparent at the molecular level. In contrast, fish exposed to the high NP concentration showed physiological (e.g. elevated LSI) and gene expression changes (e.g. induction of vitellogenin) consistent with estrogenic effects, as well as decreased lymphocytes in the peripheral blood and more limited alteration in immune system related pathways in the liver transcriptome. Fish exposed to high ATZ or NP concentrations suffered higher mortality than the control group following disease challenge with L. anguillarum. Microarray analysis of the liver transcriptome revealed a total of 211 unique, annotated differentially-regulated genes (DRGs) following high ATZ exposure and 294 DRGs following high NP exposure, with signatures that included alterations to a number of immune-system related processes and pathways. Functional (enrichment) analysis revealed effects on immune system function, metabolism, oxygen homeostasis, cell cycle, DNA damage, and other processes affected by ATZ or NP exposure. Overall this study provides evidence at multiple levels of biological organization that both ATZ and NP are immunotoxic and highlights the potential risk posed by these chemicals to wild fish populations. Total of 24 microarrays. 1 experimental sample and 1 pooled reference sample per microarray. Total of 8 individual samples (replicates) per treatment group. Three (3) treatment groups: control, atrazine (ATZ, 555 ug/L) and nonylphenol (NP, 18 ug/L).