Normal and shortened photoperiods in liver, ovary, and pituitarty
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ABSTRACT:
ORGANISM(S): Oncorhynchus tshawytscha Osmerus mordax Salmo salar Oncorhynchus mykiss Coregonus clupeaformis
PROVIDER: GSE19478 | GEO | 2009/12/15
SECONDARY ACCESSION(S): PRJNA122267
REPOSITORIES: GEO
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Project description:This study compared changes in gene expression in an oviparous female fish, the rainbow trout (Oncorhynchus mykiss), under two different photoperiod treatments, a natural photoperiod (NP) and a shortened photoperiod (SP; 60% of NP). Gene expression in the liver, ovary and pituitary were measured at one-four week intervals over the course of the reproductive cycle in each treatment. Total RNA was harvested from these tissues, cDNA prepared, and hybridized on the 16K GRASP cDNA microarray. Established indices of reproductive development (ovulation, gonadosomatic index, mean oocyte diameter, and plasma hormone levels) were also measured. The SP fish failed to ovulate and their reproductive trajectory was clearly different from the NP group, which ovulated as expected. A comparative examination of the reproductive indices in both groups shows that ovarian development initiated in the SP group and proceeded relatively normally for about two-thirds of the reproductive cycle. Plasma follicle-stimulating hormone levels were higher in the SP fish from the cycle onset. This may have dampened E2 synthesis, preventing the positive feedback signal on the pituitary for the normal, rapid increase in luteinizing hormone late in the cycle. Transcriptome analysis used an unsupervised k-means hierarchical clustering method to visualize changes in gene expression in the different organs from the NP fish that were assumed to represent the normal pattern leading to successful ovary development. In the NP, fish four, five, and six unique gene clusters were identified in the liver, ovary, and pituitary, respectively. These clusters ranged in size from 22 genes in one of the pituitary clusters to 302 genes in the liver. These clusters were then applied to the SP fish to determine if and how they were altered. The expression patterns of most genes in the SP fish were notably altered from the first time point. A SP in female rainbow trout initiated a rapid change in tr anscript levels within the liver, ovary, and pituitary, leading to ovarian failure and apparently disrupting normal endocrine signaling between the pituitary and ovary. Normal photoperiod: Two channel experiment; T=0 versus T= up to 330 days post spawn. 3 biological replicates for the later time points paired with a pooled laboratory standard t=0 control. One replicate per array Shortened photoperiod: Two channel experiment; T=0 versus T= up to 216 days post spawn. 3 biological replicates for the later time points paired with a pooled laboratory standard t=0 control. One replicate per array
2010-05-18 | E-GEOD-19478 | biostudies-arrayexpress
Project description:Metabolic processes and sexual maturation closely interact during the long-distance reproductive migration of many fish species to their spawning grounds. In the present study, we have for the first time used exercise experimentally to investigate the effects on sexual maturation in rainbow trout. Pubertal autumn-spawning seawater-raised female rainbow trout Oncorhynchus mykiss (n=26; 50-cm, 1.5-kg) were rested or swum at a near optimal speed of 0.75 body-lengths per second in a 6,000 L swim-flume under natural reproductive conditions (16 °C fresh-water, starvation, 8h-light:16h-dark photoperiod). Fish were sampled after arrival and subsequently after 10 days (resting or swimming 307 km) and 20 days (resting or swimming 636 km). Ovarian development was significantly reduced in the swimmers. Analysis of the expression of key factors in the reproductive axis included pituitary kiss1-receptor, lh and fsh and ovarian lh-receptor, fsh-receptor, aromatase and vitellogenin-receptor (vtgr). Swimmers had lower pituitary lh and ovarian vtgr expression than resters. Furthermore, the number of late vitellogenic oocytes was lower in swimmers than in resters, probably resulting from the lower vtgr expression, and vitellogenin plasma levels were higher. Therefore, swimming exercise suppresses oocyte development possibly by inhibiting vitellogenin uptake. Transcriptomic changes that occurred in the ovary of exercised fish were investigated using a salmonid cDNA microarray platform. Protein biosynthesis and energy provision were among the sixteen functional categories that were all down-regulated in the ovary. Down-regulation of the transcriptomic response in the ovary illustrates the priority of energy reallocation and will save energy to fuel exercise. A swimming-induced ovarian developmental suppression at the start of vitellogenesis during long-term reproductive migration may be a strategy to avoid precocious muscle atrophy.
2010-02-05 | GSE20131 | GEO
Project description:Metabolic processes and sexual maturation closely interact during the long-distance reproductive migration of many fish species to their spawning grounds. In the present study, we have for the first time used exercise experimentally to investigate the effects on sexual maturation in rainbow trout. Pubertal autumn-spawning seawater-raised female rainbow trout Oncorhynchus mykiss (n=26; 50-cm, 1.5-kg) were rested or swum at a near optimal speed of 0.75 body-lengths per second in a 6,000 L swim-flume under natural reproductive conditions (16 °C fresh-water, starvation, 8h-light:16h-dark photoperiod). Fish were sampled after arrival and subsequently after 10 days (resting or swimming 307 km) and 20 days (resting or swimming 636 km). Ovarian development was significantly reduced in the swimmers. Analysis of the expression of key factors in the reproductive axis included pituitary kiss1-receptor, lh and fsh and ovarian lh-receptor, fsh-receptor, aromatase and vitellogenin-receptor (vtgr). Swimmers had lower pituitary lh and ovarian vtgr expression than resters. Furthermore, the number of late vitellogenic oocytes was lower in swimmers than in resters, probably resulting from the lower vtgr expression, and vitellogenin plasma levels were higher. Therefore, swimming exercise suppresses oocyte development possibly by inhibiting vitellogenin uptake. Transcriptomic changes that occurred in the ovary of exercised fish were investigated using a salmonid cDNA microarray platform. Protein biosynthesis and energy provision were among the sixteen functional categories that were all down-regulated in the ovary. Down-regulation of the transcriptomic response in the ovary illustrates the priority of energy reallocation and will save energy to fuel exercise. A swimming-induced ovarian developmental suppression at the start of vitellogenesis during long-term reproductive migration may be a strategy to avoid precocious muscle atrophy. In order to simulate the natural reproductive conditions of anadromous salmonids, experiments were performed with sea water-raised rainbow trout, Oncorhynchus mykiss. Resters and swimmers were starved during the experiment, seawater was replaced by fresh water and photoperiod was changed. These changes were expected to affect reproductive parameters but as âbackgroundâ effect because both resters as swimmers were experiencing these conditions at the same time in the same set-up. Any additional effects in swimming fish would thus be caused by swimming only. Pubertal autumn spawning rainbow trout (n=26; ~50 cm, ~1.5 kg) were purchased from a Danish exporter (Frederiksvaerk Aleexport) where they had been raised for 2 years in freshwater followed by 4 months in sea water cages at 10 â°. They were transferred by truck within 16 h to Spakenburg (Spakenburg Paling, The Netherlands) and subsequently in the same water in a similar holding tank to the swim-flume at Leiden University (The Netherlands). The next day, 5 randomly chosen fish were sampled as âstartâ-group while others were randomly divided into a ârestâ-group (n=10) and a âswimâ-group (n=11). During the following 4 days, the brackish 10 â° water was stepwise replaced by freshwater at 16 °C and photoperiod was changed from 16L:8D to 8L:16D. Fish were then acclimatized for two days to their new conditions. Subsequently, swimmers were first swum at a speed of 0.33 body-lengths per second (BL/s) which was increased the next day to the final, near optimal speed of 0.75 BL/s (0.34 m/s or 29.4 km/day). Fish were sampled after 10 days (5 resters and 5 swimmers) and 20 days (5 resters and 6 swimmers). At sampling, fish were anesthetized using oil of cloves that was commercially purchased from a drugstore (diluted 1:10 in ethanol and used at a dosage of 1.5 ml/l). Fish were euthanized by decapitation and dissected for the ovary which was flash frozen in liquid nitrogen. RNA was isolated from pituitary and ovary samples according to the TRIZOL reagent protocol by Invitrogen (Baro, Spain). Isolated RNA was DNAse treated using RQ1 DNAse Promega (Madison, USA) and reverse transcribed using Superscript IIITM (Baro, Spain) according to the manufacturerâs protocol. Microarray analyses were performed on ovarian tissue for 20-days-swimmers vs. 20-days-resters. A rainbow trout cDNA microarray platform was used that was previously validated and described by Koskinen et al., 2004ab, Krasnov et al., 2005, MacKenzie et al., 2006ab, 2008 and Djordjevic et al., 2009, and deposited in GEO under accession number GPL1212, the original cDNA microarray (SFA2.0 chip), and GPL6154; the updated 1.8 K platform. This platform compromises 1818 genes representing 366 functional categories. Total RNA was extracted from flash frozen samples from experimental fish of the 20-days-swim group (n=5) and 20-days-rest group (n=5) like described before. Total RNA corresponding to pooled samples from the swim or rest groups was labeled with Cye3 and Cye5-dCTP (GE Healthcare, Barcelona, Spain) using SuperScript III reverse transcriptase (Invitrogen, Baro, Spain) and oligo(dT) primer. In our experience, reverse labeling combined with multiple replication of spots provide robust normalization and high statistical power of analyses. cDNA was purified with MicroconYM30 (Millipore). The slides were pretreated with 1% BSA(fraction V), 20 à SSC, 10% SDS (30 min at 50°C) and washed with 2 à SSC (3 min) and 0.2 à SSC (3 min) and hybridized overnight in cocktail containing 50 à Denhardt's, 20 à SSC, 10% SDS, 10μg/μl polyadenylate and 10 μg/μl yeast tRNA. All chemicals were from Sigma-Aldrich. Scanning was performed with ScanArray 5000 and images were processed with QuantArray (GSI Luminomics). The measurements in spots were filtered by criteria I/B ⥠3 and (I-B)/(SI + SB) ⥠0.6, where I and B are the mean signal and background intensities and SI, SB are the standard deviations. After subtraction of mean background, LOWESS normalization was performed. To assess differential expression of genes, the normalized log intensity ratios (expression ratio) were analyzed with Student's t-test (P <0.05). Validation of the microarray was performed by Q-PCR of 6 differentially expressed genes (DEGs) as described above. The used primers were either published (Alpha-globin I-1: Donate Jimeno, 2008) or designed, again by using the Genamics software.
2010-06-24 | E-GEOD-20131 | biostudies-arrayexpress
Project description:Foxl2 is a forkhead transcription factor essential for proper reproductive function in females. It is expressed in the somatic cell population of the gonad (granulosa cells) which forms the follicles of the ovary, the structures responsible for embedding and nurturing the oocytes during their development. FOXL2 directly regulate the aromatase that synthesizes estrogens CYP19A1, thus promoting female differentiation, as well as acting as a repressor of the male factors SOX9 and DMRT1.Expression is also found in the eyelids, pituitary gland and uterus. In the goat, frog and many fish species FOXL2 is a sex-determining gene which, when deleted, leads to female-to-male sex reversal.
2022-07-11 | PXD024439 | Pride
Project description:We sequenced mRNA from four biological replicates of each tissue before (T1) and after the onset of maturation (T2, T3, T4). A total of 3.2 billion paired-end reads were mapped against the Atlantic salmon reference genome with 72% mapping efficiency to create an average depth of 50 million reads per library. The number of differentially expressed genes (DEGs) increased with elapsed time following the onset of the long light photoperiod for the two BPG axis tissues (pituitary and ovary). Of these, the ovary underwent the most dramatic remodelling over time with 403, 1,709 and then 3,497 DEGs observed at timepoints T2, T3 and T4 respectively. This increasing trajectory of differential ngene expression, coupled with the elevated GSI following the light stimuli, strongly suggests the experimental approach successfully initiated the onset of maturation. Next, we identified clusters of DEGs in each of the analysed tissues, which describe their physiological roles. The identity of the DEGs, in response to the onset of maturation, revealed the key players involved in the earliest triggers into maturation. Among these, upregulation of genes encoding specififc pituitary hormones such as gonadotropins along with genes encoding transcription factors (such as GATA2) are significant in controlling onset of maturation. In addition, genes encoding pituitary hormone receptors and follicular development were upregulated in ovary.
2020-08-28 | GSE157001 | GEO
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.
2012-11-01 | GSE38726 | GEO
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).
2012-11-01 | E-GEOD-38726 | biostudies-arrayexpress
Project description:This experiment was set up to evaluate the effect of the duration of a short photoperiod (winter-like conditions, 8 hours light, 14 hours dark) on the smolt transcriptome in liver and gill. Fish were kept at constant light before fish were split between treatment tank or control tanks. Treatment tanks either experienced 2 weeks of short photoperiod or 8 weeks of short photoperiod. The control fish were kept in constant winter-like conditions. After winter, the fish were brought back to constant light for 4 weeks. Sampling was done before transition to short photoperiod, at the end of winter period and four weeks after transition back to constant light. Control fish were sampled at the same time points as the treatment group.
2022-05-20 | E-MTAB-10526 | biostudies-arrayexpress
Project description:We performed a time course experiment, whereby animals were manipulated with photoperiod before tissues were collected across the time window when animals commence sexual development. We performed whole genome bisulfite sequencing of three salmon tissues (pituitary, ovary and liver) at both the beginning and end of the experiment, to take a first look at the patterns of DNA methylation and examine how they change in response to the onset of an important life history trait. Comparison across timepoints revealed 6,373 differentially methylated regions (DMRs), of which approximately 50% were located within genes (DMGs). The ovary underwent the most profound remodelling, with a strong bias towards increased methylation levels (hyper-methylation). Weak correlation was observed considering all available genes, suggesting methylation may not be the key epigenomic regulator of global expression in the context of our experiment. However, we found a significant overlap between DMGs and differentially expressed genes in the ovary. Taken together, our results suggest chromatin remodelling genes play a role in the commitment of animals to the sexual maturation pathway.
2020-08-28 | GSE156997 | GEO
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.
2012-06-03 | E-GEOD-33715 | biostudies-arrayexpress