Intestinal cellular localization of PCNA protein and CYP1A mRNA in Atlantic salmon Salmo salar L. exposed to a model toxicant

<p>Abstract</p> <p>Background</p> <p>The aim of the study was to examine the intestinal cellular localization of proliferating cell nuclear antigen (PCNA) and cytochrome P450 A1 (CYP1A) expression in Atlantic salmon <it>Salmo salar </it>L. exposed to a model toxicant. The stress response was induced by intraperitoneal injection of four salmon with a single dose (50 mg/kg) of the CYP1A inducer β-naphthoflavone (BNF) and intestinal tissue (mid and distal intestine; MI and DI) was sampled seven days later. Samples for histology and gene transcription analysis were collected from four exposed fish and four control fish. PCNA was assessed by immunohistochemistry, CYP1A mRNA was studied by <it>in situ </it>hybridization (ISH) and finally the transcription of five genes was quantified by real-time quantitative RT-PCR (real-time RT-PCR); two detoxifying genes (CYP1A and glutathione S-transferase; GST), a stress marker gene (heat shock protein 70; HSP70), PCNA and a gene marker of apoptosis (caspase 6A).</p> <p>Results</p> <p>PCNA protein and CYP1A mRNA were successfully localized in the intestinal cells (MI) of both experimental groups. At the cellular level, BNF significantly lowered intestinal cell proliferation and increased the CYP1A mRNA levels compared to the control group. The real-time RT-PCR data, which showed an increased mRNA expression both in the MI and DI of 139- and 62-fold, respectively, confirmed the increased cellular CYP1A mRNA levels detected using ISH. HSP70 expression was also up-regulated in the exposed fish. The other examined genes did not show any differential regulation in the experimental fish group.</p> <p>Conclusion</p> <p>This study showed that CYP1A mRNA had a specific intestinal cellular transcription pattern in Atlantic salmon exposed to BNF. At the cellular level CYP1A mRNA expression was always observed at or around the cell nucleus close to the basolateral cell membrane and at the tissue level CYP1A mRNA expression was most frequently observed in the basal and apex area of the intestinal folds. Taken together, a link between the intestinal detoxification system (CYP1A) and cell renewal system (PCNA) is indicated with these two processes being inversely correlated in BNF exposed fish.</p

Undersøkelser av hydrokarboner og organiske miljøgifter i sedimenter fra MAREANO-området i 2019

Havforskningsinstituttet har gjennomført målinger av hydrokarboner (PAH) i sedimenter fra ti lokaliteter i MAREANO-området. I overflatesedimenter ble det i tillegg målt totalt hydrokarbon innhold (THC), bromerte flammehemmere (PBDE), klorerte miljøgifter (PCB og pesticider) og ved syv lokaliteter også «nye» organiske miljøgifter (PFAS, alkylfenoler, PFR, klorparafiner og siloksaner). Her ble det også inkludert en ny gruppe klorparafiner, LCCP, ikke undersøkt tidligere i MAREANO programmet. Prøvene var innsamlet i 2019 vest for Bjørnøya, i Kongsfjorden og i åpent hav vest for Svalbard, og i Kvitøyrenna. Relativt høye nivåer av hydrokarboner ble funnet på de fleste lokalitetene, som følge av naturlige tilførsler fra Svalbard. Dette gjelder først og fremst oljerelaterte lette og alkylerte PAH og er i samsvar med tidligere studier av Svalbard-området. Benzo[a]pyren ligger i Miljødirektoratets klasse II (AA-EQS). På dyphavslokalitetene vest for Bjørnøya var PAH-nivåene lavere og gjenspeiler sannsynligvis grensen for området påvirket av tilførslene fra Svalbard. PAH-konsentrasjonsprofiler i kjernene tydet for det meste på ingen endring i moderne sedimentlag og bekreftet slikt sett naturlig opphav av hydrokarbonene. Nivåene av menneskeskapte organiske miljøgifter av alle typer listet ovenfor var lave eller meget lave. Nivåene tilsvarte Miljødirektoratets klasse II for de stoffene som det er etablert tilstandsklasser for. Nivåer av LCCP var i alle undersøkte områder under kvantifiseringsgrensen på 10 µg/kg tv.publishedVersio

Undersøkelser av hydrokarboner og organiske miljøgifter i sedimenter fra MAREANO-området i 2020

Havforskningsinstituttet har gjennomført målinger av hydrokarboner (PAH) i sedimenter fra 17 lokaliteter i MAREANOområdet. I overflatesedimenter ble det i tillegg målt totalt hydrokarbon innhold (THC), bromerte flammehemmere (PBDE), klorerte miljøgifter (PCB og pesticider) og ved syv lokaliteter også «nye» organiske miljøgifter (PFAS, alkylfenoler, dekloraner, PFR, klorparafiner og siloksaner). Prøvene var innsamlet i 2020 i områdene Frøyabanken, Haltenbanken, Trænadjupet, Trænabanken og Sklinnadjupet på Norskehavssokkel. Relativt lave nivåer av hydrokarboner ble funnet ved alle lokalitetene. Benzo[a]pyren var i Miljødirektoratets klasse I («Bakgrunn») eller II («God tilstand»), mens PAH16 var i tilstandsklasse I overalt. PAH-konsentrasjonsprofiler i kjernene tydet for det meste på tilførsler av pyrogene PAH i moderne sedimentlag, knyttet til antropogen påvirkning. Ved enkelte lokaliteter i Sklinnadjupet er det også funnet økte nivåer av petrogene PAH (NPD) i dypere sedimentlag, som sannsynligvis forklares av naturlige tilførsler. Nivåene av menneskeskapte organiske miljøgifter av alle typer listet ovenfor var lave eller meget lave. Nivåene tilsvarte Miljødirektoratets klasse II for de stoffene som det er etablert tilstandsklasser for, med unntaket av PFOS som var i tilstandsklasse III «Moderat») ved noen av lokalitetene. Det er ikke funnet tegn på forurensning med klorerte miljøgifter som kunne forklare tidligere funn av forhøyete nivåer av PCB og dioksiner i kveite fra deler av Sklinnadjupet.publishedVersio

Spatial transcription of CYP1A in fish liver

<p>Abstract</p> <p>Background</p> <p>The aim of this work was to study how evenly detoxifying genes are transcribed spatially in liver tissue of fish. Ten Atlantic salmon <it>Salmo salar </it>were intraperitoneally injected with 50 mg/kg of the strong CYP1A inducer β-naphthoflavone and liver tissue harvested seven days later. The liver from 10 control and 10 exposed fish were split into eight sections, RNA extracted and three reference (β-actin, elongation factor 1A_B(EF1A_B)) and two detoxifying genes (CYP1A and GST) quantified with real-time RT-PCR. The cellular localization of the EF1A_Band CYP1A mRNA in the liver of control and β-naphthoflavone treated fish was then determined by <it>in situ </it>hybridization (ISH) using EF1A_Band CYP1A biotinylated oligonucleotide probes.</p> <p>Results</p> <p>The study shows that genes encoding phase I and phase II conjugating enzymes are unevenly transcribed in different parts of the liver of Atlantic salmon seven days after a single-dose of β-naphthoflavone exposure. Transcription of CYP1A and GST was higher in the middle section of the liver compared to the distal and proximal parts of the organ. The ISH data suggest that CYP1A transcription happens mainly in hepatocyte cells in the liver, and that hepatocytes in the vicinity of blood vessels respond stronger to β-naphthoflavone than cells further away from the blood supply.</p> <p>Conclusion</p> <p>Overall, the qRT-PCR and ISH results reported here suggest that gene expression analysis should be performed on as pure cell populations as possible. If bulk tissue samples are to be used, one should always check how evenly the target genes are expressed in tissue sections and organs in every study.</p

Miljøgifter i fisk og fiskevarer 2017 – Dioksiner og dioksinlignende PCB, ikke-dioksinlignende PCB, polybromerte flammehemmere og tungmetaller i marine oljer til humant konsum

Contaminants in fish and fish products 2017 – Dioxins and dioxin-like PCBs, non-dioxin-like PCBs, polybrominated flame retardants and heavy metals in marine oils for human consumptionMiljøgifter i fisk og fiskevarer 2017 – Dioksiner og dioksinlignende PCB, ikke-dioksinlignende PCB, polybromerte flammehemmere og tungmetaller i marine oljer til humant konsumpublishedVersio

Chlorpyrifos-induced dysfunction of lipid metabolism is not restored by supplementation of polyunsaturated fatty acids EPA and ARA in Atlantic salmon liver cells

Exposure to contaminants can lead to accumulation of lipids in the liver. This study aimed to examine whether eicosapentaenoic acid (EPA) and arachidonic acid (ARA) supplementation can protect fish cells against the negative impact of chlorpyrifos (CPF). Atlantic salmon hepatocytes were exposed to either 100 μM CPF, 200 μM EPA, 200 μM ARA, or combinations of these for 48 h, and endpoints included lipid droplet formation, gene expression, and global metabolomic analysis. The results showed that polyunsaturated fatty acid (PUFA) supplementation modified the cell lipid composition, reduced uptake of CPF and increased the cellular number and size of lipid droplets. CPF exposure induced the transcription of ppara and fabp3, and reduced the levels of several PUFAs, and lead to accumulation of monoacylglycerols (MAGs) in the cells. Supplementation of EPA or ARA did not prevent CPF-induced accumulation of MAGs and only to a limited degree rescued the response on other lipids. CPF exposure further reduced energy metabolism, a response partly restored by PUFA supplementation. Reduced levels of glutathione indicated oxidative stress; an effect not ameliorated by the PUFAs. Altogether, this study shows that PUFA supplementation only modestly protects Atlantic salmon hepatocytes against the negative impact of CPF.publishedVersio

Mesopelagic Species and Their Poential Contribution to Food and Feed Security - A Case Study from Norway

The projected increase in global population will demand a major increase in global food production. There is a need for more biomass from the ocean as future food and feed, preferentially from lower trophic levels. In this study, we estimated the mesopelagic biomass in three Norwegian fjords. We analyzed the nutrient composition in six of the most abundant mesopelagic species and evaluated their potential contribution to food and feed security. The six species make up a large part of the mesopelagic biomass in deep Norwegian fjords. Several of the analyzed mesopelagic species, especially the fish species Benthosema glaciale and Maurolicus muelleri, were nutrient dense, containing a high level of vitamin A1, calcium, selenium, iodine, eicopentaenoic acid (EPA), docosahexaenoic acid (DHA) and cetoleic acid. We were able to show that mesopelagic species, whose genus or family are found to be widespread and numerous around the globe, are nutrient dense sources of micronutrients and marine-based ingredients and may contribute significantly to global food and feed security.publishedVersio

Micro- and nanoplastic toxicity on aquatic life: Determining factors

Plastic pollution has become a major environmental concern due to its omnipresence and degradation to smaller particles. The potential toxicological effects of micro- and nanoplastic on biota have been investigated in a growing number of exposure studies. We have performed a comprehensive review of the main determining factors for plastic particle toxicity in the relevant exposure systems, from publications until including the year 2018. For a focused scope, effects of additives or other pollutants accumulated by the plastic particles are not included. In summary, current literature suggests that plastic particle toxicity depends on concentration, particle size, exposure time, particle condition, shape and polymer type. Furthermore, contaminant background, food availability, species, developmental stage and sex have major influence on the outcome of plastic particles exposures. Frequently reported effects were on body and population growth, energy metabolism, feeding, movement activity, physiological stress, oxidative stress, inflammation, the immune system, hormonal regulation, aberrant development, cell death, general toxicity and altered lipid metabolism. Several times reported were increased growth and food consumption, neuro-, liver- or kidney pathology and intestinal damage. Photosynthesis disruption was reported in studies investigating effects on phytoplankton. For the currently unquantified plastic particles below 10 μm, more toxic effects were reported in all aquatic life, as compared to plastic particles of larger size.publishedVersio

Kartlegging av fremmedstoffer i mesopelagiske arter fra norske farvann - Mesopelagisk fisk fra Norskehavet og Sognefjorden

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