Characterization of the Zoarces viviparus liver transcriptome using massively parallel pyrosequencing

<p>Abstract</p> <p>Background</p> <p>The teleost <it>Zoarces viviparus </it>(eelpout) lives along the coasts of Northern Europe and has long been an established model organism for marine ecology and environmental monitoring. The scarce information about this species genome has however restrained the use of efficient molecular-level assays, such as gene expression microarrays.</p> <p>Results</p> <p>In the present study we present the first comprehensive characterization of the <it>Zoarces viviparus </it>liver transcriptome. From 400,000 reads generated by massively parallel pyrosequencing, more than 50,000 pieces of putative transcripts were assembled, annotated and functionally classified. The data was estimated to cover roughly 40% of the total transcriptome and homologues for about half of the genes of <it>Gasterosteus aculeatus </it>(stickleback) were identified. The sequence data was consequently used to design an oligonucleotide microarray for large-scale gene expression analysis.</p> <p>Conclusion</p> <p>Our results show that one run using a Genome Sequencer FLX from 454 Life Science/Roche generates enough genomic information for adequate <it>de novo </it>assembly of a large number of genes in a higher vertebrate. The generated sequence data, including the validated microarray probes, are publicly available to promote genome-wide research in <it>Zoarces viviparus</it>.</p

Thyroid function and immune status in perch (Perca fluviatilis) from lakes contaminated with PFASs or PCBs

The environment contains a multitude of man-made chemicals, some of which can act as endocrine disruptors (EDCs), while others can be immunotoxic. We evaluated thyroid disruption and immunotoxic effects in wild female perch (Perca fluviatilis) collected from two contaminated areas in Sweden; one site contaminated with perand polyfluoroalkyl substances (PFASs) and two sites contaminated with polychlorinated biphenyls (PCBs), with one reference site included for each area. The hepatic mRNA expression of thyroid receptors alpha and beta, and the thyroid hormone metabolising iodothyronine deiodinases (dio1, dio2 and dio3) were measured using real-time PCR, while the levels of thyroid hormone T3 in plasma was analysed using a radioimmunoassay. In addition, lymphocytes, granulocytes, and thrombocytes were counted microscopically. Our results showed lower levels of T3 as well as lower amounts of lymphocytes and granulocytes in perch collected from the PFAS-contaminated site compared to reference sites. In addition, expressions of mRNA coding for thyroid hormone metabolising enzymes (dio2 and dio3) and thyroid receptor alpha (thra) were significantly different in these fish compared to their reference site. For perch collected at the two PCB-contaminated sites, there were no significant differences in T3 levels or in expression levels of the thyroid-related genes, compared to the reference fish. Fish from one of the PCB-contaminated sites had higher levels of thrombocytes compared with both the second PCB lake and their reference lake; hence PCBs are unlikely to be the cause of this effect. The current study suggests that lifelong exposure to PFASs could affect both the thyroid hormone status and immune defence of perch in the wild

Combination of Reverse and Chemical Genetic Screens Reveals Angiogenesis Inhibitors and Targets

We combined reverse and chemical genetics to identify targets and compounds modulating blood vessel development. Through transcript profiling in mice, we identified 150 potentially druggable microvessel-enriched gene products. Orthologs of 50 of these were knocked down in a reverse genetic screen in zebrafish, demonstrating that 16 were necessary for developmental angiogenesis. In parallel, 1280 pharmacologically active compounds were screened in a human cell-based assay, identifying 28 compounds selectively inhibiting endothelial sprouting. Several links were revealed between the results of the reverse and chemical genetic screens, including the serine/threonine (S/ T) phosphatases ppp1ca, ppp1cc, and ppp4c and an inhibitor of this gene family; Endothall. Our results suggest that the combination of reverse and chemical genetic screens, in vertebrates, is an efficient strategy for the identification of drug targets and compounds that modulate complex biological systems, such as angiogenesis

Naproxen affects multiple organs in fish but is still an environmentally better alternative to diclofenac

The presence of diclofenac in the aquatic environment and the risks for aquatic wildlife, especially fish, have been raised in several studies. One way to manage risks without enforcing improved wastewater treatment would be to substitute diclofenac (when suitable from a clinical perspective) with another non-steroidal anti-inflammatory drug (NSAID) associated with less environmental risk. While there are many ecotoxicity-studies of different NSAIDs, they vary extensively in set-up, species studied, endpoints and reporting format, making direct comparisons difficult. We previously published a comprehensive study on the effects of diclofenac in the three-spined stickleback (Gasterosteus aculeatus). Our present aim was to generate relevant effect data for another NSAID (naproxen) using a very similar setup, which also allowed direct comparisons with diclofenac regarding hazards and risks. Sticklebacks were therefore exposed to naproxen in flow-through systems for 27 days. Triplicate aquaria with 20 fish per aquarium were used for each concentration (0, 18, 70, 299 or 1232 mu g/L). We investigated bioconcentration, hepatic gene expression, jaw lesions, kidney and liver histology. On day 21, mortalities in the highest exposure concentration group unexpectedly reached >= 25 % in all three replicate aquaria, leading us to terminate and sample that group the same day. On the last day (day 27), the mortality was also significantly increased in the second highest exposure concentration group. Increased renal hematopoietic hyperplasia was observed in fish exposed to 299 and 1232 mu g/L. This represents considerably higher concentrations than those expected in surface waters as a result of naproxen use. Such effects were observed already at 4.6 mu g/L in the experiment with diclofenac (lowest tested concentration). Similar to the responses to diclofenac, a concentration-dependent increase in both relative hepatic gene expression of c7 (complement component 7) and jaw lesions were observed, again at concentrations considerably higher than expected in surface waters. Naproxen bioconcentrated less than diclofenac, in line with the observed effect data. An analysis of recent sales data and reported concentrations in treated sewage effluent in Sweden suggest that despite higher dosages used for naproxen, a complete substitution would only be expected to double naproxen emissions. In summary, naproxen and diclofenac produce highly similar effects in fish but the environmental hazards and risks are clearly lower for naproxen. Hence, if there are concerns for environmental risks to fish with diclofenac, a substitution would be advisable when naproxen presents an adequate alternative from a clinical point-of-view

Regional övervakning 2021 : Metaller och organiska miljögifter i abborre

Under hösten 2021 genomförde Länsstyrelsen Västra Götaland en undersökning med syfte att studera spridning av metaller och organiska miljögifter i regionen samt att samla in data inför statusklassingen inom vattenförvaltningscykel 4 (2022–2027). Abborrar fångades in från elva utvalda sjöar med kända eller misstänkta påverkanskällor. Samlingsprover bestående av muskel analyserades med avseende på högfluorerade ämnen (PFAS/PFOS), dioxiner och dioxinlika föreningar, polyklorerade bifenyler (PCB), bromerade flamskyddsmedel (PBDE) samt kvicksilver. Arsenik, bly, kadmium, koppar, krom, nickel och zink analyserades i samlingsprover från lever. Uppmätta halter jämfördes mot gränsvärden och bedömningsgrunder inom vattenförvaltningen (HVMFS 2019:25). Resultaten visar att halterna av det perfluorerade ämnet PFOS låg över gränsvärdet inom vattenförvaltningen i fem av elva sjöar. Högst var halterna i abborre från Lilla Issjön och Västra Ingsjön där halterna låg ca åtta gånger över gränsvärdet inom vattenförvaltningen. I Bottensjön och Guttasjön uppmättes PFOS i halter som översteg gränsvärdet ca två–tre gånger. Halten PFOS i abborre från Landvettersjön låg strax över gränsvärdet inom vattenförvaltningen. Kvicksilverhalten låg över gränsvärdet i biota inom vattenförvaltningen i samtliga sjöar. Även det bromerade flamskyddsmedlet PBDE översteg gränsvärdet inom vattenförvaltningen i åtta av de elva sjöarna. Dessa resultat stödjer den bedömning inom vattenförvaltningen som klassar samtliga svenska vattenförekomster med sämre än god status med avseende på kvicksilver och PBDE. Uppmätta halter av dioxiner och dioxinlika föreningar låg under gränsvärdet i biota inom vattenförvaltningen i abborre från de elva undersökta sjöarna. Inga halter av PCB översteg bedömningsgrunden förutom i abborre från Guttasjön där halten låg strax över. Summan av de uppmätta halterna för PFAS-förningarna PFOS, PFOA, PFNA samt PFHxS (PFAS4) jämfördes även mot Livsmedelsverkets temporära åtgärdsnivå för PFAS4 i egenfångad fisk (Livsmedelsverket, 2023 a). Detta gjordes för att avgöra om en utökad undersökning bör initieras med fisk i konsumtionsstorlek för alla de arter som fångas och konsumeras regelbundet av fritidsfiskare. I fem sjöar låg halterna för PFAS4 över denna temporära åtgärdsnivå för egenfångad fisk. För metaller där gränsvärden inom vattenförvaltningen saknas gjordes en jämförelse mot halter i abborre från referenssjöar analyserade inom Naturvårdsverkets nationella övervakning av miljögifter och metaller i limnisk biota. Dessa referenssjöar har liten lokal mänsklig påverkan och uppmätta halter anses därför beskriva den generella bakgrundsbelastningen av miljögifter i fisk. Resultaten visar att de uppmätta halterna av vissa metaller i abborre låg över de halter som uppmätts inom den nationella övervakningen av abborre. Detta gäller arsenik i Vassbotten och Åsunden, bly i Östra Ingsjön och Landvettersjön samt krom och nickel i abborrar från Landvettersjön