Global hepatic gene expression in rainbow trout exposed to sewage effluents
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ABSTRACT:
ORGANISM(S): Oncorhynchus mykiss
PROVIDER: GSE37574 | GEO | 2012/05/10
SECONDARY ACCESSION(S): PRJNA163639
REPOSITORIES: GEO
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Project description:Effluents from sewage treatment plants contain a mixture of micropollutants with the potential of harming aquatic organisms. Thus, addition of advanced treatment techniques to complement existing conventional methods has been proposed. Some of the advanced techniques could, however, potentially produce additional compounds affecting exposed organisms by unknown modes of action. In the present study the aim was to improve our understanding of how exposure to different sewage effluents affects fish. This was achieved by explorative microarray and quantitative PCR analyses of hepatic gene expression, as well as relative organ sizes of rainbow trout exposed to different sewage effluents (conventionally treated, granular activated carbon, ozonation (5 or 15 mg/L), 5 mg/L ozone plus a moving bed biofilm reactor, or UV-light treatment in combination with hydrogen peroxide). Exposure to the conventionally treated effluent caused a significant increase in liver and heart somatic indexes, an effect removed by all other treatments. Genes connected to xenobiotic metabolism, including cytochrome p450 1A, were differentially expressed in the fish exposed to the conventionally treated effluents, though only effluent treatment with granular activated carbon or ozone at 15 mg/L completely removed this response. The mRNA expression of heat shock protein 70 kDa was induced in all three groups exposed to ozone-treated effluents, suggesting some form of added stress in these fish. The induction of estrogen-responsive genes in the fish exposed to the conventionally treated effluent was effectively reduced by all investigated advanced treatment technologies, although the moving bed biofilm reactor was least efficient. Taken together, granular activated carbon showed the highest potential of reducing responses in fish induced by exposure to sewage effluents. The fish exposure was carried out in March 3-17, 2008 at Henriksdal STP (Stockholm, Sweden) using a large scale pilot plant with parallel treatment lines under ethic permits approved by the local animal committee in Gothenburg (permission no. 36-2007). A thorough description of the different treatment steps (both conventional and advanced) and the experimental setup during the exposure (Fig. 1) has been previously described elsewhere (Samuelsson et al., 2011). In brief, the raw influent underwent conventional activated sludge treatment to generate a reference effluent (Conventional Activated Sludge; CAS). This includes mechanical treatment (removal of large objects using grids with 3 mm column width); primary sedimentation; biological treatment (activated sludge aged 20 days); secondary sedimentation; sand filter. The additional advanced treatment processes were granular activated carbon (GAC), ozonation at 5 mg/L (OZ5) or 15 mg/L (OZ15), ozonation 5 mg/L followed by a moving bed biofilm reactor (MBBR) and irradiation by ultraviolet radiation (0.75 Wh/L) plus hydrogen peroxide (10 mg/L; UH). Two aquaria were used for positive controls. As the tap water available is not as well accepted by the fish, and to better reflect the organic content and overall chemistry of surface water, the control aquaria (TW1 and TW2, together TW) contained carbon-filtered tap water supplemented by 2% of conventionally treated reference effluent. We consider evaluation of implementation and running costs to be outside the scope of this paper. Juvenile rainbow trout (Oncorhynchus mykiss; 113M-BM-123 g; mean bodyweight M-BM-1 standard deviation) of both sexes were obtained from Antens Laxodling AB (AlingsM-CM-%s, Sweden). Rainbow trout is a commonly used species for this type of studies and our lab have ample experience using this species. Furthermore, rainbow trout of sufficient size for metabolomic studies (Samuelsson et al., 2011) can easily be obtained. Finally, the use of trout provides the opportunity for comparisons with other studies (e.g. Gunnarsson et al., 2009 and Albertsson et al., 2010). During an acclimatization period of four days on site, the fish were kept in tanks containing carbon-filtered tap water + 2% reference effluent. On the onset of the experiment, the fish were randomly distributed among eight 100 L aquaria (n=25/aquarium), supplied with treated effluent from the different parallel treatment lines. Aquaria duplicates were used for the controls. During both the acclimatization period as well as the 14 day exposure, the aquaria were aerated and the fish were not fed to reduce variability due to differences in food intake. It should be stressed that trout easily cope with food deprivations for several weeks (Kullgren et al., 2010). Measurements of temperature (13.5M-BM-10.5M-BM-0C), oxygen saturation (97M-BM-13%), pH (7.4M-BM-10.3), conductivity and flow rate were monitored 5 d per week throughout the exposure. In addition, to evaluate differences in removal efficiency between the treatments, total organic carbon (TOC), 7-day biochemical oxygen demand (BOD7), suspended solids (SS), total nitrogen (Tot-N) and total phosphorus (Tot-P) were measured in all effluents (Samuelsson et al., 2011). The sampling took place during two consecutive days (day 14 and 15) due to the large number of fish. For each day, an equal number of fish from each treatment was sampled in random order and killed by a blow to the head. The fish were weighed, their fork length was measured and their sex was determined by macroscopical observation of their gonads. Liver samples were collected for several different studies (hence sample size limitations), frozen on dry ice and stored at -70M-BM-0C until analysis. Homogenization of the frozen liver tissue was carried out using Tissuelyser (Qiagen, Hilden, Germany) and hepatic total RNA was extracted and purified using QIAcube and RNeasyM-BM-. Plus Mini Kit (Qiagen). The RNA quantity and quality were assessed by spectrophotometric measurements with the Nanodrop 1000 (NanoDrop Technologies, Wilmington, DE). To ensure that no degradation had occurred, the isolated RNA was analyzed using Experion automated electrophoresis (Bio-Rad, Hercules, CA). A 15k rainbow trout gene expression microarray was designed for the RT analyzer platform (febit, Heidelberg, Germany) by using The Institute for Genomic Research (TIGR) Rainbow Trout Gene Index (RTGI) database version 7.0 (http://compbio.dfci.harvard.edu/tgi/). Details on the probe design strategy, but for eelpout (Zoarces viviparus), and transcript selection strategy are described elsewhere (Kristiansson et al., 2009; Cuklev et al., 2011). However, in the present study, singletons and non-annotated expressed sequence tags (ESTs) were replaced by newly well-annotated ESTs in rainbow trout. When available, transcripts at GenBank (http://www.ncbi.nlm.nih.gov/nucleotide) were used. In our lab, results from similar microarrays using the same platform have shown good correlation with quantitative polymerase chain reaction (qPCR) data (Gunnarsson et al., 2009b; Kristiansson et al., 2009; Cuklev et al., 2011; Lennquist et al., 2011). To reduce variation in estrogen-responsive genes, only males were used for the subsequent gene expression analyses. Biotinylated antisense RNA (aRNA) was synthesized using MessageAmpM-bM-^DM-" II-Biotin Enhanced Single Round aRNA Amplification Kit (AmbionM-BM-.). The aRNA samples (20 M-BM-5g) were vacuum dried in a vacuum centrifuge, dissolved in 10 M-BM-5l water and fragmented according to the manufacturerM-bM-^@M-^Ys protocol. The following steps described in this subchapter were all performed by febit. Oligonucleotide arrays were synthesized by photo-controlled in situ synthesis using the Geniom One system (febit). Each biochip consists of eight individually accessible micro channels, each of which is referred to as a microarray in this manuscript. Eight individual samples from each aquarium were included in the analysis. In total, 64 microarrays were analyzed. A customized protocol, described in detail elsewhere (Cuklev et al., 2011), was used for prehybridization and hybridization. All samples were randomly placed on the biochips, with one sample from each exposure on each biochip. Signals were detected using the internal CCD-camera system of the RT analyzer instrument (febit) and quantified using the Geniom Wizard software. Integration times were between 156 and 570 ms, determined automatically by the instrument software. All microarray data processing and statistical calculations were performed in R-2.12.2 (www.r-project.org; R Development Core Team, 2010). The quality of pre- and post normalized arrays was verified with box- and MA plots. The data analysis was performed in the R-package LIMMA (Smyth, 2005). Data were normalized using the M-bM-^@M-^XquantileM-bM-^@M-^Y method. Moderated t-statistics and adjusted p-values of differential expression were calculated using the empirical Bayes model.
2012-05-09 | E-GEOD-37574 | biostudies-arrayexpress
Project description:Rivers containing effluents from water treatment plants are complex soups of compounds, ranging from pharmaceuticals to natural hormones. Male fathead minnows (Pimephales promelas) were exposed for 3 weeks to effluent waters from the Metropolitan Wastewater Treatment Plant in St. Paul, MN. Fish were tested for their competitive nest holding behavior. Changes in vitellogenin were measured and these were correlated to changes in gene expression using a 22,000 gene microarray developed specifically for fathead minnows. Significant changes in gene expression were observed in both liver and gonad, which correlate to phenotypic changes of vitellogenin induction and reduced competitive behavior. We also compared by real-time PCR the expression changes in key genes related to steroid biosynthesis and metabolism in fish exposed to the effluent as well as in fish exposed to a model estrogen and a model androgen. While the gene expression signature from effluent-exposed fish shared some elements with estrogen and androgen signatures, overall it was different, underscoring the complexity of compounds present in sewage and their different modes of action.
2010-10-30 | GSE23490 | GEO
Project description:Despite recent knowledge of the potential environmental impact that compounds present in municipal wastewater effluents, including contaminants of emerging concern (CECs), may have, the implications of fish exposure to this contaminant mixtures are not completely understood. The effects caused by effluent CECs may be subtle and diverse, thus the need for sensitive and comprehensive tools such as gene expression to detect such responses. In this study, we conducted laboratory exposures that examined plasma concentrations of vitellogenin (VTG), changes in secondary sexual characteristics and gene expression in sexually mature male fathead minnows (Pimephales promelas) exposed to environmentally realistic (0.5%) and higher (5%) concentrations of municipal wastewater effluents. Secondary and primary treated effluents were used. Several of the 32 CECs investigated were detected, including pharmaceuticals, personal care products, hormones, current use pesticides and industrial compounds. The percent of males with detectable levels of VTG was higher in fish exposed to effluent treatments. An increased number of males with changes in secondary sexual characteristics (e.g. development of ovipositors), was observed in fish exposed to 5% effluent treatments. Gene expression data indicated that overall expression patterns were characteristic to each effluent. Higher numbers of differentially expressed genes were observed in fish exposed to primary treated effluent when compared to controls. Differentially expressed genes belonged to several functional categories, including xenobiotic metabolism, estogenicity and energy/metabolism processes. Gene expression data provided information to understand some of the mechanisms behind the effects observed at higher biological levels. To investigate gene expression responses resulting from exposure to POTW effluents, two laboratory experiments were conducted using effluent from San Diego (Point Loma; SD) and Los Angeles (Hyperion; LA). The LA effluent received secondary treatment and the SD effluent received advanced primary treatment. Treatments used during exposures consisted of negative controls (moderately hard water), positive controls (E2), and 0.5% and 5% effluent concentrations. The 0.5% concentration of effluent represented an environmentally realistic exposure level. The 5% effluent concentration represented a higher level at which we expected biological responses. The exposures lasted 14 days. Treatments: EFFHa = 5% primary treated effluent EFFHb = 5% secondary treated effluent EFFLa = 0.5% primary treated effluent E2a = Estradiol, positive control for primary effluent E2b = Estradiol, positive control for secondary effluent CTRLa = Moderately hard water, negative control for primary effluent CTRLb = Moderately hard water, negative control for secondary effluent
2011-05-18 | E-GEOD-29350 | biostudies-arrayexpress
Project description:Contaminants of emerging concern (CECs) in treated municipal effluents have the potential to adversely impact exposed organisms prompting elevated public concern. Using transcriptomic tools, we investigated changes in gene expression and cellular pathways in the liver of male fathead minnows (Pimephales promelas) exposed to 5% concentrations of full secondary-treated (HTP) or advanced primary-treated (PL) municipal wastewater effluents containing CECs. Gene expression changes were associated with apical endpoints (plasma vitellogenin and changes in secondary sexual characteristics). Of 32 effluent CECs analyzed, 28 were detected including pharmaceuticals, personal care products, hormones, and industrial compounds. Transcript patterns differed between effluents, however < 10% of these had agreement in the detected response (e.g. transcrips involved in xenobiotic detoxification, oxidative stress and apoptosis) in both effluents. Exposure to PL effluent caused changes in transcript levels of genes involved in metabolic pathways (e.g., lipid transport and steroid metabolism). Exposure to HTP effluent affected transcripts involved in signaling pathways (e.g., focal adhesion assembly and extracellular matrix). Exposure to both effluents produced significantly higher levels of plasma VTG and changes in secondary sexual characteristics (e.g., ovipositor development). Taken together the results suggest, a potential association between some transcriptomic changes and higher biological responses following effluent exposure; and a potential adverse outcome pathway following exposure to complex chemical mixtures containing CECs -. Furthermore, this study identified responses in key genes and pathways not previously implicated in exposure to CECS, , which could be consistent with effluent exposure (e.g., oxidative stress) in addition to other pathway responses specific to the effluent type. This may be useful for assessing the adverse health effects of fish by effluents exposure to CECs.
2011-05-18 | GSE29350 | GEO
Project description:Ketoprofen and diclofenac are non-steroidal anti-inflammatory drugs (NSAIDs) often used for similar indications, and both are frequently found in surface waters. Diclofenac affects organ histology and gene expression in fish at around 1 µg/L. Here, we exposed rainbow trout to ketoprofen (1, 10 and 100 µg/L) to investigate if this alternative causes less risk for pharmacological responses in fish. The bioconcentration factor from water to fish blood plasma was <0.05 (4 for diclofenac based on previous studies). Ketoprofen only reached up to 0.6‰ of the human therapeutic plasma concentration, thus the probability of target-related effects was estimated to be fairly low. Accordingly, a comprehensive analysis of hepatic gene expression revealed no consistent responses. In some contrast, trout exposed to undiluted, treated sewage effluents bioconcentrated ketoprofen and other NSAIDs much more efficiently, according to a meta-analysis of recent studies. Neither of the setups is however an ideal representation of the field situation. If a controlled exposure system with a single chemical in pure water is a reasonable representation of the environment, then the use of ketoprofen is likely to pose a lower risk for wild fish than diclofenac, but if bioconcentration factors from effluent-exposed fish are applied, the risks may be more similar.
2012-06-01 | GSE37628 | GEO
Project description:Rivers containing effluents from water treatment plants are complex soups of compounds, ranging from pharmaceuticals to natural hormones. Male fathead minnows (Pimephales promelas) were exposed for 3 weeks to effluent waters from the Metropolitan Wastewater Treatment Plant in St. Paul, MN. Fish were tested for their competitive nest holding behavior. Changes in vitellogenin were measured and these were correlated to changes in gene expression using a 22,000 gene microarray developed specifically for fathead minnows. Significant changes in gene expression were observed in both liver and gonad, which correlate to phenotypic changes of vitellogenin induction and reduced competitive behavior. We also compared by real-time PCR the expression changes in key genes related to steroid biosynthesis and metabolism in fish exposed to the effluent as well as in fish exposed to a model estrogen and a model androgen. While the gene expression signature from effluent-exposed fish shared some elements with estrogen and androgen signatures, overall it was different, underscoring the complexity of compounds present in sewage and their different modes of action. Fathead minnow 22,000 gene arrays were designed by EcoArray (Alachua, FL) and were purchased from Agilent. Array hybridizations were performed using a reference design, where each sample was compared to a reference sample. The reference consisted of equal amounts of RNA from control female and male tissues (liver, brain and gonad) and was prepared as a standard for several experiments. Four replicates consisting of four different individuals were analyzed for each of the tissues, liver and gonad for both the control and the effluent-exposed fish. cDNA synthesis, cRNA labeling, amplification and hybridization were performed following the manufacturerM-bM-^@M-^Ys kits and protocols (Agilent Low RNA Input Fluorescent Linear Amplification Kit and Agilent 60-mer oligo microarray processing protocol; Agilent, Palo Alto, CA). Ovarian and liver samples from the fish were labeled with Cy5 while the reference sample was labeled with Cy3.
2010-10-29 | E-GEOD-23490 | biostudies-arrayexpress
Project description:Many biomonitoring tools/approaches have been proposed to assess presence of endocrine active chemicals (EACs) and their biological effects in the field. Although these tools have provided valuable information, they are often limited by their specificity for certain groups of EACs and they may not account for interactions between EACs. This study aims to evaluate utility of transcriptomic and metabolomic technologies for effects monitoring in the field, and to advance integration of omic and environmental chemistry data sets. The objective was to utilize transcriptomic biomonitoring to determine the relative contribution of wastewater treatment plant effluents to biological effects observed in fish exposed to ambient waters receiving the effluents. Adult male fathead minnow were exposed to treated wastewater effluent or stream water up or downstream the plant in three different watersheds for 4 days. After exposure, the liver of 5-7 fish per treatment per site (i.e 19-21 fish from each watershed) were analyzed by microarrays. The transcriptomic profiles were compared to control fish exposed to Lake Superior filtered water.
2014-01-04 | E-GEOD-49098 | biostudies-arrayexpress
Project description:The transcriptome analysis by the human DNA microarray was applied to evaluate the impacts of whole wastewater effluents from the membrane bioreactors (MBRs) and the activated sludge process (AS), on the biological processes of human hepatoma HepG2 cells. The three conventional bioassays (i.e., cytotoxicity tests and bioluminescence inhibition test) and chemical analysis of the domestic effluent standards were conducted in parallel since they are well-established methods with previous applications to wastewater. A significant variation of effluent quality was sdemonstrated among the tested effluents despite that all effluents met the 40 national effluent standards. The three conventional bioassays supported the result of the transcriptome analysis, indicating the comparable or even higher sensitivity of the new assay. The most superior effluent quality was found in the MBR operated at a relatively long sludge retention time (i.e., 40 days) and small membrane pore size (i.e., 0.03 M-NM-<m). In addition, functional analysis of the differentially expressed genes revealed that the effluents made various impacts on the cellular functions, suggesting the transcriptome analysis by DNA microarray as more comprehensive, rapid and sensitive tool to detect multiple impacts of the whole effluents. Moreover, the potential genetic markers were proposed to quantitatively evaluate the treatability of the wastewater effluents. In this study, we examined the gene expression alteration in human hepatoma cell line, HepG2 exposed to the raw wastewater, effluents from three types of membrane bioreactors (MBRs), and the activated sludge process. Wastewater DNA microarray with 8795 human genes. MQ water was used as control. For duplicate, two dishes were prepared for each sample and individually treated in parallel.
2013-03-29 | E-GEOD-45605 | biostudies-arrayexpress
Project description:Effect of chlorination on the toxicity of wastewater effluents treated by activated sludge (AS) and submerged membrane bioreactor (S-MBRB) systems to HepG2 human hepatoblastoma cells was investigated. In addition to cytotoxicity assay, the DNA microarray-based transcriptome analysis was performed to evaluate the change in modes of toxic actions (MOAs) of effluents by chlorination. Effluent organic matters (EfOM) and disinfection by-products (DBPs) were characterized by using Fourier transform mass spectrometry (FT-MS). The cytotoxicity of AS effluent was elevated by chlorination, while the toxicity of S-MBRB effluent was reduced. The averaged O/C ratio of EfOM in S-MBRB effluent was lower than that in AS effluent. The results of the transcriptome and FT-MS analyses suggested that lower O/C molecules influenced on M-bM-^@M-^\response to hormone stimulusM-bM-^@M-^] and M-bM-^@M-^\acute inflammatory responseM-bM-^@M-^] but those were decreased by chlorination, which consequently reduced cytotoxicity. On the other hand, larger number of DBPs and other molecules were increased in AS effluents by chlorination. Those molecules might influence on M-bM-^@M-^\cellular metabolic processM-bM-^@M-^], which consequently elevated cytotoxicity. Therefore, the combination of the toxicity assays and chemical analysis demonstrated the changes in severity of cytotoxicity and MOAs by chlorination, and the difference of chemical characteristics which relate to those toxicity changes. We examined the gene expression alteration in human hepatoma cell line, HepG2 exposed to the chlorinated wastewater effluents from membrane bioreactor and the activated sludge process. Human Genome Focus Array, which represents 8,795 verified human sequences, was used. All effluent samples were concentrated by using solid phase extraction (SPE). SPE fraction from MQ water was used as controll. For duplicate, two dishes were prepared for each sample and individually treated in parallel.
2013-06-21 | E-GEOD-48157 | biostudies-arrayexpress
Project description:Hepatic transcriptional profiling of fish exposed to sewage to evaluate temporal and concentration trends.
2012-12-01 | GSE38925 | GEO