I'm currently working on a PCB contamination dataset in several flatfish and round fish species. I'd like to compare the cytochrome P450 activity to explain the inter-specific differences in PCB contamination.
So I'd like to know is somewhere is aware of studies comparing enzymatic activity between flat and round species, expecting that flatfish species living close to contamination in sediment would have developed higher detoxification activity.
Thanks for your help !
I think that you may have hint when you consider why polar bear's liver can accumulate so much vitamin A which is untolerable level for other animals such as human since a member of P450 such as CYP26 are responsible for degradation of VA. Do you consider another possibility that faltfishes possess higher level of metallothionein which can absorb heavy metal such as PCBs than ordinorly round fishes?. Since genomic information on Senegal sole, Japanese flounder and Atlantic halibut have been well accumulated, you may get help from someone who is involved in these sequencing project.
Isn't pelagic vs benthic the more correct comparison than round vs flat? There are a lot of benthic fish species other than flatfish, and flatfish species such as the Atlantic halibut are not really benthic, but spending most of their lifecycle in the water column.
My aquatic toxicology colleagues at Univ Gothenburgu use eelpout as a marine, benthic bioindicator species, see publications by https://www.researchgate.net/profile/Lars_Foerlin.
Thanks for these answers. To be more accurate, I'm answering if flatfish living close to the sediment, or even in the sediment may have developed some adaptive abilities (such as a higher CYP activity) to cope with this high exposure. And I would like to use this ability to compare PCB levels in several benthic species, whether round or flat.
Thanks Björn for the link, I'll check if I can find useful information in the papers by your colleagues.
Hi Pierre,
The logics in your supposition is an obvious, and based on the following strong experimental and epidemiologic data. Thus, in Stefanelli et al. paper entitled “Organochlorine compounds in tissues of swordfish (Xiphias gladius) from Mediterranean Sea and Azores island” (Mar Pollut Bull. 49(11-12):938-50, 2004), to develop sensitive biomarkers for the evaluation of toxicological risk, 34 congeners of PCB were measured in swordfishes (Xiphias gladius) taken from the Mediterranean Sea along the Sicilian coast (Strait of Messina, Italy) and in the PCB-clear Atlantic Ocean along the Azores Islands. In the tissues of Mediterranean swordfishes the sum of the determined PCBs congeners ranged from 4.61 to 4651.17 ng g(-1) on fresh tissue basis. In the liver of Azores Island swordfishes lower levels of summation PCBs (8.43-294.17 ng/g w.w.). Thereafter, Maria Fossi et al continue that approach by publishing a paper entitled “Endocrine Disruptors in Mediterranean Top Marine Predators” (ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH 13(3):204-7, 2006), where they investigated P4501A1 activity (namely, ethoxyresorufin-o-deethylase) in the pelagic fishes live in neither close to the bottom nor near the shore, such as the swordfish and also in tuna fish from the same Strait of Messina. A 4-year survey revealed almost 3 times higher P4501A1 activity in the liver of that species, comparing to that ones from Atlantic Ocean along the Azores Islands. The role of increased bottom level of PCBs along the Strait of Messina statistically correlated with the above induction of ethoxyresorufin-o-deethylase in the livers from swordfish and tuna fish.
Best wishes,
Ilya
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