First assessment of POPs and cytochrome P450 expression in Cuvier’s beaked whales (Ziphius cavirostris) skin biopsies from the Mediterranean Sea

Abstract

The Cuvier's beaked whale (Ziphius cavirostris) is one of the least known cetacean species worldwide. The decreasing population trend and associated threats has led to the IUCN categorising the Mediterranean subpopulation as Vulnerable on the Red List of Threatened Species. This study aimed to investigate for the first time the ecotoxicological status of Cuvier's beaked whale in the NW Mediterranean Sea. The study sampled around the 20% of the individuals belonging to the Ligurian subpopulation, collecting skin biopsies from free-ranging specimens. The levels of polychlorinated biphenyl (PCBs), polybrominated diphenyl ethers (PBDEs) and induction of cytochrome's P450 (CYP1A1 and CYP2B isoforms) were evaluated. Results highlighted that the pattern of concentration for the target contaminants was PCBs > PBDEs and the accumulation values were linked to age and sex, with adult males showing significantly higher levels than juvenile. Concerns raised by the fact that 80% of the individuals had PCB levels above the toxicity threshold for negative physiological effects in marine mammals. Therefore, these findings shed light on this silent and serious threat never assessed in the Mediterranean Cuvier’s beaked whale population, indicating that anthropogenic pressures, including chemical pollution, may represent menaces for the conservation of this species in the Mediterranean Sea.

Ecotoxicological Characterization of Type C Killer Whales From Terra Nova Bay (Ross Sea, Antarctica): Molecular Biomarkers, Legacy, and Emerging Persistent Organic Contaminants

“…Cytochrome-like bands for the CYP1A1 (59 kDa) and CYP2B (56 kDa) were identified and quantified in the dermal part of five out of seven skin biopsies (Table 1). CYP1A1 and CYP2B protein expression have a broad range of expression among the samples, where CYP1A1 has higher values than CYP2B, as already shown in a previous study on the same species (Fossi et al, 2014) and other cetaceans (Hoydal et al, 2018;Baini et al, 2020).…”

“…Analysis of cytochrome P450 CYP1A1 and CYP2B, used in this study as a potential marker of POP exposure, were analyzed in the dermal part of the skin biopsies of RSKW using Western Blot (WB) and a semiquantitative analysis of the data according to Fossi et al (2008). Subsamples of biopsies (about 30 mg) were homogenized using a Tissue Lyser II (Qiagen, Hilden, Germany) in the aryl-hydrocarbon-receptor buffer (1:10), and the lysate processed according to Baini et al (2020). Semiquantitative analysis was performed using the Quantity One software (1-D Analysis Software, Bio-Rad Laboratories, Hercules, CA, United States) and molecular weights calculated with multiple regression models using the Precision Plus Protein TM Standard (Bio-Rad Laboratories, Hercules, CA, United States).…”

“…CYP1A1 and CYP2B proteins have been detected in cetacean skin. The different expression of these CYP isoforms has been related to the exposure to lipophilic contaminants (AhR inducers) such as organochlorine compounds [OCs, polycyclic aromatic hydrocarbons (PAHs), and PBDEs both ex vivo and in in-field studies (Godard, 2004;Baini et al, 2020)].…”

Morganella morganii septicemia and concurrent renal crassicaudiasis in a Cuvier’s beaked whale (Ziphius cavirostris) stranded in Italy

“…The health status of the animal was also compromised by a high burden of organic pollutants with demonstrated detrimental effects on the immune system (Marsili et al, 2004;Marsili et al, 2019;Centelleghe et al, 2019). Blubber concentrations of organochlorine compounds (OCs), particularly DDTs and PCBs, were very high both compared to the values found in other CBWs sampled in the Mediterranean basin (Hatzianestis et al, 1998;Baini et al, 2020) and compared to those measured in BWs from other parts of the world (Knap and Jickells, 1983;Bachman et al, 2014). The blubber PCBs concentrations in the studied specimen of Cuvier's beaked (77.8 mg/kg l.w.)…”

Pollution Biomarkers in the Framework of Marine Biodiversity Conservation: State of Art and Perspectives

“…The authors outlined them as contaminant burdens, and in turn, CYP1A1 expression levels were influenced by the different trophic positions of the studied species. More recently, Baini et al [84] assessed levels of polychlorinated biphenyl (PCBs), polybrominated diphenyl ethers (PBDEs), and induction of cytochrome's P450 in skin biopsies of Cuvier's beaked whale, whose Mediterranean subpopulation has been categorized as vulnerable on the IUCN (International Union for Conservation of Nature) Red List of Threatened Species. Recently, Mancia et al [85] explored the application of epigenetics to the study of the stress response related to xenobiotics exposure in the Mediterranean fin whale (Balaenoptera physalus).…”