Toxicological studies of marine mammals: In vitro experiments with fin whale (Balaenoptera physalus) fibroblasts and in silico studies of cytochrome P450 proteins
Master thesis
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Date
2024-08-19Metadata
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- Master theses [289]
Abstract
Whales and marine mammals are an important part of the marine ecosystems, but also vulnerable for exposure to chemical pollution in the water. Studies of these animals are important for guiding our understanding of the oceans and how to protect the whales.
Since these animals are difficult to work with in their natural environment, in addition to it being ethically problematic to perform experiments on live animals, other approaches have to be taken into consideration.
Cells are an important tool to understand responses of the animals to pollutants, without having to work with the animals directly. In this thesis, fibroblasts from fin whale (Balaenoptera physalus) were used in this aspect, by first optimizing their growth conditions by including NAC and bFGF in the cell medium and study growth on coated surfaces. Thereafter, the cells were exposed to the persistent organic pollutants (POPs) PCB153, trans-nonachlor, DDE and DDT, before cellular responses in the form of metabolic activity, lysosomal activity and membrane integrity were investigated.
From this, optimal concentrations of NAC and bFGF and the use of Cell+ plates seemed to increase the number of cells. Exposure to POPs resulted in increase in lysosomal activity for all contaminants in addition to potential increased membrane integrity, here excluding the PCB153.
In addition, in silico approaches may be a great help to understanding underlying concepts that are not as easily performed in the lab. Here, protein sequences from important cytochrome P450 (CYP450) families from several marine mammals were aligned and compared to discover differences and evolutionary paths among the species in addition to giving an indication about how the organisms handles exposure to different substances.
The results from alignment with CYP1-family showed some differences that could be interesting for further analysis, while studies of the CYP3-family indicated a decrease in their expression. In addition, unique amino acids in CYP51A1 from abyssal grenadier that was postulated could affect the protein’s tolerance to pressure, were compared to the same sequences in marine mammals, including some deep diving species, but no shared amino acids were found.