Spatial Variation in Transcript and Protein Abundance of Atlantic Salmon during Feeding Migration in the Baltic Sea

Abstract

The fitness and reproductive output of fishes can be affected by environmental disturbances. In this study, transcriptomics and label-free proteomics were combined to investigate Atlantic salmon (Salmo salar) sampled from three different field locations within the Baltic Sea (Baltic Main Basin (BMB), Gulf of Finland (GoF), and Bothnian Sea (BS)) during marine migration. The expression of several stress related mRNAs and proteins of xenobiotic metabolism, oxidative stress, DNA damage, and cell death were increased in salmon from GoF compared to salmon from BMB or BS. Respiratory electron chain and ATP synthesis related gene ontology-categories were upregulated in GoF salmon, whereas those associated with RNA processing and synthesis, translation, and protein folding decreased. Differences were seen also in metabolism and immune function related gene expression. Comparisons of the transcriptomic and proteomic profiles between salmon from GoF and salmon from BMB or BS suggest environmental stressors, especially exposure to contaminants, as a main explanation for differences. Salmon feeding in GoF are thus “disturbed by hazardous substances”. The results may also be applied in evaluating the conditions of pelagic ecosystems in the different parts of Baltic Sea.

Transcriptomic profiling of male European eel ( Anguilla anguilla ) livers at sexual maturity

“…It may also be a result of the maturation process. These findings and the observation that several genes involved in protein biosynthesis were downregulated at sexual maturity are similar to the gene expression pattern found in salmon during feeding migration (Kanerva et al, 2014). In salmon, these changes were attributed to stress and environmental contamination.…”

Oxidative metabolism of chemical pollutants in marine organisms: molecular and biochemical biomarkers in environmental toxicology

“…The exposure to contaminated sediments of the European eel, A. anguilla , confirmed frequent dissociations between transcriptional and catalytic responses of several antioxidant defenses, depending on tissue and typology, intensity, or time of chemical exposure (Table ) . In a recent study on the Atlantic salmon, S. salar , transcriptomic and proteomic analyses were integrated to characterize geographical and temporal differences in the redox status of this fish sampled from different areas of the Baltic Sea . Specimens from the Gulf of Finland generally showed different levels of mRNA and proteins related to several pathways, including xenobiotic metabolism, oxidative stress, DNA damage, cell death, metabolism, and the immune system.…”

“…Specimens from the Gulf of Finland generally showed different levels of mRNA and proteins related to several pathways, including xenobiotic metabolism, oxidative stress, DNA damage, cell death, metabolism, and the immune system. Although a significant covariation was globally observed between transcriptional and proteomic data, genes involved in regulation of redox state frequently exhibited lack of correlation, or even opposite trends of variation between mRNA and protein levels …”

Developing specific molecular biomarkers for thermal stress in salmonids

“…It must be taken into account that all the discussion about the function of the proteins is based on the assumption that the gene and protein expression are tightly coupled. Moderate correlations between gene expression and protein activity are also common [ 82 , 83 ], possibly because of post-transcriptional and post-translational modifications [ 84 ]. However, changes in mRNA levels may be one of the first indicators of a physiological change or response [ 22 , 85 ].…”