Transcriptomic analyses in a benthic fish exposed to contaminated estuarine sediments through laboratory and in situ bioassays

Abstract

The transcription of contaminant response-related genes was investigated in juvenile Senegalese soles exposed to sediments from three distinct sites (a reference plus two contaminated) of a Portuguese estuary (the Sado, W Portugal) through simultaneous 28-day laboratory and in situ bioassays. Transcription of cytochrome P450 1A (CYP1A), metallothionein 1 (MT1), glutathione peroxidase (GPx), catalase (CAT), caspase 3 (CASP3) and 90 kDa heat-shock protein alpha (HSP90AA) was surveyed in the liver by real-time PCR. CASP3 transcription analysis was complemented by surveying apoptosis through the TUNEL reaction. After 14 days of exposure, relative transcription was either reduced or decreased in fish exposed to the contaminated sediments, revealing a disturbance stress phase during which animals failed to respond to insult. After 28 days of exposure all genes' transcription responded to contamination but laboratory and in situ assays depicted distinct patterns of regulation. Although sediments revealed a combination of organic and inorganic toxicants, transcription of the CYP1A gene was consistently correlated to organic contaminants. Metallothionein regulation was found correlated to metallic and organic xenobiotic contamination in the laboratory and in situ, respectively. The transcription of oxidative stress-related genes can be a good indicator of general stress but caution is mandatory when interpreting the results since regulation may be influenced by multiple factors. As for MT1, HSP90 up-regulation has potential to be a good indicator for total contamination, as well as the CASP3 gene, even though hepatocyte apoptosis depicted values inconsistent with sediment contamination, showing that programmed cell death did not directly depend on caspase transcription alone.

Do laboratory exposures represent field exposures? Effects of sediments contaminated by wood industry on yolk-sac fry of rainbow trout (Oncorhynchus mykiss)

“…The contaminated sediments attenuated the growth of the fry only in the field exposures. Differences in the outcomes between laboratory and in situ sediment exposures have also been described previously among invertebrates (Conrad et al 1999, Pereira et al 2000, Kater et al 2001, Ringwood and Keppler 2002, Anderson et al 2004, Mann et al 2010) and fishes (Costa et al 2011a, Costa et al 2011b, Costa et al 2012. In most cases, the sediments have been less toxic in the laboratory than in the field (Conrad et al 1999, Pereira et al 2000, Kater et al 2001, Ringwood and Keppler 2002, Anderson et al 2004, Hose et al 2006, Mann et al 2010.…”

Seawater acclimation and inositol monophosphatase isoform expression in the European eel (Anguilla anguilla) and Nile tilapia (Orechromis niloticus)

“…Although osmoregulatory roles for inositol have been documented across many animal and plant species, it is only recently that this organic osmolyte has been implicated in osmoregulation in a restricted number of euryhaline teleosts (13,14,22,23). Euryhaline teleost fish are capable of movement between habitats with wide-ranging salinity, and SW acclimation is accompanied by a myriad of molecular, physiological, cellular, and behavioral changes, which are essential for successful adaptation not only to the increased salinity (19) but also to the possibility of temperature change (21), as well as to exposure to a different cocktail of environmental toxins and pathogens (10). The role that organic osmolytes play in the adaptive responses to higher salinity and other environmental stresses has only recently come under investigation.…”

Effect of increasing temperature in the differential activity of oxidative stress biomarkers in various tissues of the Rock goby, Gobius paganellus

“…Ferreira et al, 2005;Padmini et al, 2009;Costa et al, 2011;Vinagre et al, 2012;Madeira et al, 2013). Yet, hepatopancreas, digestive gland, gills, blood and hemolymph, have also been frequently used when analysing fish, crustaceans or bivalves (e.g.…”