Project description:In this study, we attempt to characterize the transcriptomic profile of the Asian seabass gonads at various developmental stages. The protandric Asian seabass or barramundi (Lates calcarifer) typically matures as a male at approximately 2M-bM-^@M-^S4 years of age and then changes sex to a female in later years. For this experiment, Asian seabass of several ages were collected from the Marine Aquaculture Center of the Agri-Food & Veterinary Authority of Singapore and from farms around Singapore. There were no treatments carried out in this experiment. The gonads were examined by histology and classified according to sexual maturation status as described by Guiguen and colleagues (Guiguen et al. Environmental Biology of Fishes, 1994). Altogether, we analyzed 22 gonadal samples that could be classified into six different types of gonads. Total 22 samples: Adult Ovaries (F3-stage; 5 years old fish) : 4 Adult Testes (M3-stage; 5 years old fish) : 4 Early Testes (M3-stage; 8-9 months old fish) : 3 Early Transforming Gonads (>2 years old fish) : 3 Late Transforming Gonads (>2 years old fish) : 4 Undifferentiated Gonads (4.5 months old fish) : 4
Project description:Rainbow darter (Etheostoma caeruleum) are a small benthic fish found in North America. This species is sensitive to sewage effluent in the environment, showing the presence of intersex in up to 80% of males in near-field areas in the Grand River, ON. To learn more about the molecular events associated with intersex, we developed a customized oligonucleotide microarray (4x180K) with next generation sequencing (454 Roche) to characterize molecular responses in the gonad. Transcriptomics was performed on both males and females from both a reference site and a polluted site. Males with and without intersex from the polluted site were compared to the control males. Rainbow darter were sampled from from the Grand River in May 2011. Fish were selected according to the location, gonad maturity, and intersex index. Reference fish were taken from the upstream to the urban area; exposed fish were taken from downstream of from Kitchener MWWE treatment plant.
Project description:Screening has revealed that modern-day feeds used in Atlantic salmon aquaculture might contain trace amounts of agricultural pesticides. To reach slaughter size, salmon are produced in open net pens in the sea. Unconsumed feed pellets and undigested feces deposited beneath the net pens represent a source of contamination for marine organisms. To examine the impacts of long-term and continuous dietary exposure to an organophosphorus pesticide (OP) found in Atlantic salmon feed, we fed juvenile Atlantic cod (Gadus morhua), an abundant species around North Atlantic fish farms, three concentrations (0.5, 4.2 and 23.2 mg/kg) of chlorpyrifos-methyl (CPM) for 30 days. Endpoints included liver and bile bioaccumulation, liver transcriptomics and metabolomics, as well as plasma cholinesterase activity, cortisol, liver 7-ethoxyresor-ufin-O-deethylase (EROD) activity and hypoxia tolerance. The results show that Atlantic cod can accumulate relatively high levels of CPM in the liver after continuous exposure, which is then metabolized and excreted via the bile. All three exposure concentrations led to significant inhibition of plasma cholinesterase activity, the primary target of CPM. Transcriptomics profiling pointed to effects on cholesterol and steroid biosynthesis. Metabolite profiling revealed that CPM induced responses reflecting detoxification by glutathione-S-transferase, inhibition of monoacylglycerol lipase, potential inhibition of carboxylesterase, and increased demand for ATP, followed by secondary inflammatory responses. A gradual hypoxia challenge test showed that all groups of exposed fish were less tolerant to low oxygen saturation than the controls. In conclusion, this study suggests that wild fish continuously feeding on leftover pellets near fish farms over time may be vulnerable to OPs.
Project description:The potential of an hepatic transcriptome expression profile, evaluated in a sentinel feral fish, to serve as an environmental biomarker was examined. Gene expression profiles of individuals of Lithognathus mormyrus were examined using a cDNA microarray and were correlated to the set of environmental exposure conditions at their site and date of collection. The clusters of individual gene expression profiles were reasonably related to the fish samples and several sample-specific clusters of genes, designated gene signatures of the sample, were determined. The relationship between transcriptome expression and the fish samples indicated a potential for their utilization as an environmental biomarker. Ten fish were sampled at each of two sites (Dor, Israel and Haifa, Israel) each of two years (2007 and 2008) for a total of 40 fish. All fish were hybridized to a common reference RNA population using a dye-swap design. Hence, each fish was hybridized twice vs. the reference RNA. The reference RNA was an equalized pool of the RNAs from all 10 fish comprising sample D7.
Project description:Streptococcus agalactiae is one of the most important pathogens associated with outbreaks of streptococcis in Nile tilapia farms around the world. High water temperature (above 27°C) have been described as factor predisposing for disease in fish. On the other hand, at low temperature (below 25°C) fish mortalities are no usually observed in farms. The temperature variation can modulate the expression of genes and proteins involved with metabolism, adaptation and bacterial pathogenicity, increasing or decreasing the host susceptibility to infection. The aim of this study was to evaluate the transcriptome and proteome of fish-pathogenic S. agalactiae strain (SA53) submitted to in vitro growth under different temperatures using microarray and label-free shotgun LC-HDMSE approach, and to compare the expression trends of proteins shared among GBS strains from different hosts (SA53 and NEM316). Biological triplicates of isolates were cultured in BHIT broth at 22°C or 32°C for RNA and protein isolation and submitted to transcriptomic and proteomic analysis. Total of 1730 transcripts were identified in SA53, being 107 genes differentially expressed among the temperature evaluated. A higher number of genes related with metabolism were detected as up-regulated proteins at 32°C, mainly PTS system and ABC transport system. In proteome analysis, 1046 proteins were identified in SA53 strain, being 81 proteins differentially regulated at 22 and 32ºC. Proteins involved in Defense mechanisms (V), Lipid transport and metabolism (I), and Nucleotide transport and metabolism (F) were up-regulated at 32ºC. A higher number of interactions was observed in the category F. The induction of genes/proteins involved in virulence were detected in both temperatures evaluated. A low correlation between transcriptome and proteome datasets was observed. And there is a distinct adaptation between fish and human GBS strains at the proteome level. Our study showed that the transcriptome and proteome of fish-adapted GBS strain are modulated by temperature, especially regulating the differential expression of genes/proteins involved with metabolism, adaptation and virulence, and revealing a host specificity at proteome regulation for human and fish hosts
Project description:The increased urban pressures are often associated with specialization of microbial communities. Microbial communities being a critical player in the geochemical processes, makes it important to identify key environmental parameters that influence the community structure and its function.In this proect we study the influence of land use type and environmental parameters on the structure and function of microbial communities. The present study was conducted in an urban catchment, where the metal and pollutants levels are under allowable limits. The overall goal of this study is to understand the role of engineered physicochemical environment on the structure and function of microbial communities in urban storm-water canals.
Project description:The increased urban pressures are often associated with specialization of microbial communities. Microbial communities being a critical player in the geochemical processes, makes it important to identify key environmental parameters that influence the community structure and its function.In this proect we study the influence of land use type and environmental parameters on the structure and function of microbial communities. The present study was conducted in an urban catchment, where the metal and pollutants levels are under allowable limits. The overall goal of this study is to understand the role of engineered physicochemical environment on the structure and function of microbial communities in urban storm-water canals. Microbial community structure was determined using PhyoChio (G3)