Functional knockout of the Oatp1d1 membrane transporter affects toxicity of diclofenac in zebrafish embryos.

Organic anion transporting polypeptides (OATPs) facilitate the cellular uptake of a large number of compounds. Zebrafish Oatp1d1 matches the functional capabilities of human OATP orthologs, particularly in hormone and drug transport. It is highly expressed in the liver and later stages of embryonic development, indicating its critical role in zebrafish physiology and development.

Environmental contaminants modulate transport activity of zebrafish (Danio rerio) multidrug and toxin extrusion protein 3 (Mate3/Slc47a2.1).

Zebrafish Mate3 is one of six co-orthologs of human multidrug and toxin extrusion proteins. It is highly expressed in the kidneys, intestine, testes, and brain of males. Initial interaction studies showed its interaction with xenobiotic compounds, suggesting a role in the efflux of toxic compounds.

Selective interaction of microcystin congeners with zebrafish (Danio rerio) Oatp1d1 transporter.

Microcystins (MCs) are the most studied cyanotoxins. The uptake of MCs in cells and tissues of mammals and fish species is mostly mediated by organic anion-transporting polypeptides (OATPs in humans and rodents; Oatps in other species), and the Oatp1d1 appears to be a major transporter for MCs in fish. In this study, six MC congeners of varying physicochemical properties (MC-LR, -RR, -YR, -LW, -LF, -LA) were tested by measuring their effect on the uptake of model Oatp1d1 fluorescent substrate Lucifer yellow (LY) in HEK293T cells transiently or stably overexpressing zebrafish Oatp1d1.

Environmental contaminants modulate transport activity of zebrafish organic anion transporters Oat1 and Oat3.

Organic anion transporters (OATs) are transmembrane proteins which belong to SLC22 subfamily. They are responsible for the uptake of various endo- and xenobiotics into the cells of different organs and tissues. Following our previous work on characterization of zebrafish Oat1 and Oat3, in this study we analyzed interaction of various classes of environmental contaminants with these membrane transporters using the transport activity assay with HEK293 Flp-In cell line stably overexpressing zebrafish Oat1 and Oat3, respectively.

Aerobic biodegradation of tramadol by pre-adapted activated sludge culture: Cometabolic transformations and bacterial community changes during enrichment.

The biodegradation of biorecalcitrant opioid drug tramadol (TRAM) was studied in a model biodegradation experiment performed with an enriched activated sludge culture pre-adapted to high concentration of TRAM (20 mg/L). TRAM and its transformation products (TPs) were determined by applying ultrahigh-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UHPLC-QTOF-MS), the sludge culture was characterized using a 16S rRNA gene amplicon sequencing, whereas ecotoxicological evaluation was performed based on determination of toxicity to freshwater algae. Tramadol removal was much faster (t = 1.

Sex-independent expression of chloride/formate exchanger Cfex (Slc26a6) in rat pancreas, small intestine, and liver, and male-dominant expression in kidneys.

Chloride/formate exchanger (CFEX; SLC26A6) mediates oxalate transport in various mammalian organs. Studies in Cfex knockout mice indicated its possible role in development of male-dominant hyperoxaluria and oxalate urolithiasis. Rats provide an important model for studying this pathophysiological condition, but data on Cfex (rCfex) localisation and regulation in their organs are limited.

Interaction of environmental contaminants with zebrafish (Danio rerio) multidrug and toxin extrusion protein 7 (Mate7/Slc47a7).

Zebrafish Mate7 belongs to solute carrier protein superfamily and specifically to subfamily of multidrug and toxin extruders. It is co-orthologous to mammalian Mates, and is ubiquitously expressed in zebrafish tissues with the highest expression in kidney. It has been shown to interact with both endogenous (steroid hormones) and xenobiotic compounds (pharmaceuticals), implying a role in efflux of toxic compounds.

Biodegradation study of methadone by adapted activated sludge: Elimination kinetics, transformation products and ecotoxicological evaluation.

The biotransformation study of difficult-to-degrade opioid analgesic methadone (MTHD) was performed by activated sludge culture adapted to high concentration of methadone (10 mg/L). The study included determination of elimination kinetics of the parent compound, taxonomic characterization of microbial culture, identification of biotransformation products (TPs) and assessment of ecotoxicological effects of biotransformation processes. The chemical analyses were performed by ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry, whereas the ecotoxicological assessment was made based on determinations of toxicity to freshwater algae.

Biotransformation of macrolide antibiotics using enriched activated sludge culture: Kinetics, transformation routes and ecotoxicological evaluation.

The biotransformation of three prominent macrolide antibiotics (azithromycin, clarithromycin and erythromycin) by an activated sludge culture, which was adapted to high concentrations of azithromycin (10 mg/L) was investigated. The study included determination of removal kinetics of the parent compounds, identification of their major biotransformation products (TPs) and assessment of ecotoxicological effects of biotransformation. The chemical analyses were performed by ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry, which enabled a tentative identification of TPs formed during the experiments.

Functional characterization of rainbow trout (Oncorhynchus mykiss) Abcg2a (Bcrp) transporter.

ABCG2 (BCRP - breast cancer resistance protein) belongs to the ATP-binding cassette (ABC) superfamily. It plays an important role in the disposition and elimination of xeno- and endobiotics and/or their metabolites in mammals. Likewise, the protective role of ABC transporters, including Abcg2, has been reported for aquatic organisms.

The first characterization of multidrug and toxin extrusion (MATE/SLC47) proteins in zebrafish (Danio rerio).

Multidrug and toxin extrusion (MATE) proteins are involved in the extrusion of endogenous compounds and xenobiotics across the plasma membrane. They are conserved from bacteria to mammals, with different numbers of genes within groups. Here, we present the first data on identification and functional characterization of Mate proteins in zebrafish (Danio rerio).

Characterization of glutathione-S-transferases in zebrafish (Danio rerio).

Glutathione-S-transferases (GSTs) are one of the key enzymes that mediate phase II of cellular detoxification. The aim of our study was a comprehensive characterization of GSTs in zebrafish (Danio rerio) as an important vertebrate model species frequently used in environmental research. A detailed phylogenetic analysis of GST superfamily revealed 27 zebrafish gst genes.

Identification of P-glycoprotein inhibitors in contaminated freshwater sediments.

P-glycoprotein (P-gp, ABCB1) is an important part of the multixenobiotic resistance (MXR) defense system in aquatic organisms. The main goal of this study was identification of P-gp inhibitors in contaminated sediments using the effect-directed analysis (EDA) approach. The samples were collected from the Gorjak creek (Zagreb, Croatia), a recipient of wastewater effluents from the pharmaceutical industry.

Prioritisation of organic contaminants in a river basin using chemical analyses and bioassays.

Region-specific contaminant prioritisation is an important prerequisite for sustainable and cost-effective monitoring due to the high number of different contaminants that may be present. Surface water and sediment samples from the Sava River, Croatia, were collected at four locations covering a 150-km-long river section characterised by well-defined pollution gradients. Analysis of contaminant profiles along the pollution gradients was performed by combining toxicity screening using a battery of small-scale or in vitro bioassays, which covered different modes of action, with detailed chemical characterisation based on gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/quadrupole time-of-flight mass spectrometry (LC-QTOF-MS).

Interaction of ABC transport proteins with toxic metals at the level of gene and transport activity in the PLHC-1 fish cell line.

The aim of this study was to investigate the interaction of four toxic metals with ABC transport proteins in piscine cell line PLHC-1. Cells were exposed for 24 h to 0.01-1 μM of CdCl(2), HgCl(2), As(2)O(3), or K(2)Cr(2)O(7) and the expression of a series of ABC genes (abcb1, abcc1-4) was determined using qRT-PCR.

First characterization of fish P-glycoprotein (abcb1) substrate specificity using determinations of its ATPase activity and calcein-AM assay with PLHC-1/dox cell line.

P-glycoprotein (P-gp; abcb1) is one of the major ABC transport proteins that mediates multixenobiotic resistance (MXR) defense in fish. In order to offer a sound evaluation of its ecotoxicological relevance it is critical to characterize substrate specificity of fish P-gp. Measurement of the ATPase activity is a reliable approach often used to discern type of interaction of various drugs with mammalian P-gp.

Constitutive mRNA expression and protein activity levels of nine ABC efflux transporters in seven permanent cell lines derived from different tissues of rainbow trout (Oncorhynchus mykiss).

Permanent fish cell lines have become common model systems for determining ecotoxicological effects of pollutants. For these cell lines little is known on the cellular active transport mechanisms that control the amount of a compound entering the cell, such as the MXR (multixenobiotic resistance) system mediated by ATP binding cassette (ABC) transport proteins. Therefore, for toxic evaluation of chemicals with those cells information on MXR is important.

A novel ABC transporter: the first insight into zebrafish (Danio rerio) ABCH1.

Abch1 is a novel ATP binding cassette (ABC) transporter found in fish. This study represents an initial characterisation of this transporter using phylogenetic analyses, membrane topology prediction and determination of its tissue expression pattern in adult zebrafish (Danio rerio). Blast search showed that Abch1 orthologs are not present in genomes of other vertebrate taxa and similar genes are found only in invertebrate genomes.

Gene expression analysis of the ABC efflux transporters in rainbow trout (Oncorhynchus mykiss).

In this study we examined gene expression of a series of ABC efflux transporters in various rainbow trout (Oncorhynchus mykiss) tissues. Based on their reported toxicological relevance, we have used quantitative real time PCR SYBR green quantification methodology, with combination of absolute and relative approach, to quantify RNA expression of eight ABC transporters from three different families: abcb1 and abcb11, abcc1-5 and abcg2. Level of mRNA transcripts was measured in seven tissues: liver, brain, gonads, kidney, gills, proximal intestine and distal intestine, and the obtained expression profiles were compared with data available for related mammalian tissues.

CYP1A induction potential and the concentration of priority pollutants in marine sediment samples--in vitro evaluation using the PLHC-1 fish hepatoma cell line.

The use of in vitro biotests in combination with chemical determination of priority pollutants is considered a promising approach in environmental risk assessment. The main goal of this study was to evaluate the relationship between the CYP1A induction potential and the concentration of priority pollutants (PAHs, PCBs and heavy metals) in contaminated marine sediments. Six sediment samples characterized by different types of pollution were collected from the Bay of Kvarner, Croatia.

Development and characterization of P-glycoprotein 1 (Pgp1, ABCB1)-mediated doxorubicin-resistant PLHC-1 hepatoma fish cell line.

The development of the multidrug resistance (MDR) phenotype in mammals is often mediated by the overexpression of the P-glycoprotein1 (Pgp, ABCB1) or multidrug resistance-associated protein (MRP)-like ABC transport proteins. A similar phenomenon has also been observed and considered as an important part of the multixenobiotic resistance (MXR) defence system in aquatic organisms. We have recently demonstrated the presence of ABC transporters in the widely used in vitro fish model, the PLHC-1 hepatoma cell line.