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Functional investigation of MiR92b-3p for diagnosis and miRNA-based cure in chemically induced liver injury in fish: a project description

Brzuzan P., Woźny M., Florczyk M.

Environmental Biotechnology

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2016

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Vol. 12, No. 2

40--42

EN

The continued lack of knowledge concerning the molecular background of adverse effects caused by microcystin-LR (MC-LR) is surprising. This toxin requires additional attention, not only for its ability to cause acute poisoning, but also for its ability to initiate cancer in acute doses, and potentially, to promote cancer via chronic exposure to low concentrations in drinking water. Our recent studies on whitefish (Coregonus lavaretus) revealed that long-term exposure to MC-LR resulted in severe liver injury, followed by regeneration of the liver and its unexpected resilience to further toxin uptake. These effects were accompanied by perturbations of hepatic microRNAs (miRNAs) that have target genes involved in cytoskeletal remodeling, cell metabolism, cell cycle regulation, and apoptosis. Among the most pronounced individual alterations, the reduction of MiR92b-3p expression was the most remarkable, and we suggest roles for the miRNA in the aberrant processes of liver cells. This project addresses potential involvement of MiR92b-3p in the as yet unknown regulatory network of MC-induced hepatotoxicity in fish. After a suite of biochemical, physiological, anatomical, and transcriptomic analyses in vitro and in vivo, we will show how MiR92b-3p works in a damaged liver and which processes it targets. Finally, the research will confirm if and how MiR92b-3p can be targeted therapeutically. We expect it to be shown effective enough to pave a way for its use as a tool for treatment of liver damage in fish. What is more, the RNA-based silencing technique that will be used should yield exciting data for our understanding of the system-level biology of vertebrates.

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Selection of optimal spawner-pairs based on the polymorphism of microsatellite loci in a partially-tetraploid fish species (Coregonus lavaretus)

Kaczmarczyk D., Fopp-Bayat D., Wiśniewska A.

Environmental Biotechnology

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2015

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Vol. 11, No. 1

20--25

EN

Many species that are in danger of extinction require human support in the form of captive-breeding programs to help maintain their populations in the wild.When breeding in captivity, it is important to select breeding pairs that will create the most genetically diverse progeny. Based on the polymorphism of their microsatellite loci, breeding pairs of diploid land animals have been successfully selected. In this theoretical paper, we asked how to adapt this technique to the selection of spawner pairs for restocking populations of partially tetraploid fish species. To test our calculation techniques, we used actual data on the polymorphism of the loci of captured whitefish (Coregonus lavaretus). The data enabled calculations showing which spawner pairs would create the most genetically diverse cohort of offspring if they were bred. Themethod presented in the paper can be used for breeding fish in aquaculture conditions to help conserve species.

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Exposure of whitefish (Coregonus lavaretus) eggs to native or chemically spiked sediments from Lake Thun does not lead to abnormal gonad development

Bernet D., Wahli T., Gerecke A., Segner H.

Environmental Biotechnology

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2011

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Vol. 7, No. 1

17-29

EN

A high number of whitefish, Coregonus lavaretus, from Lake Thun, Switzerland, display gonad malformations. We tested the hypothesis that exposure to sediment-borne contaminants during the embryonic life results in the development of malformed gonads later in ontogeny. The investigated contaminants were 2,4,6-trinitrotoluene (TNT), which may leak from residues in the lake sediments as consequence of former ammunition dumping into Lake Thun, as well as sulfonated naphthalene formaldehyde condensates (SNFC), which are introduced into the lake from wastewater disposals of a nearby tunnel construction site. Experimentally, whitefish eggs were exposed during 52 days from fertilization until hatching to a) an artificial sediment (control), b) an artificial sediment spiked with TNT (0.5mg*kg-1 dry weight), c) SNFC compounds dissolved in water (3µg*l-1 of each naphthalene-1-sulphonate, naphthalene-2-sulphonate, naphthalene-1,5-disulphonate, naphthalene-2,7-disulphonate), and d) sediment from Lake Thun sampled in an ammunition dumping area. To mimic in situ exposure of the eggs to the sediment-water-interface under laboratory conditions, we developed a novel contact incubation technique. After hatching, fish were reared in tap water for three years until they reached sexual maturity, and were then examined for the presence of gonad malformations. No malformations were observed in the control, in the TNT and SNFC treatment groups. In fish incubated during the embryonic stage on Lake Thun sediment, 2 out of 117 adult males (1.7%) displayed malformed gonads, which is significantly lower than levels of gonad malformations in wild whitefish from Lake Thun (on average 29% in males, 12% in females). The results from our experiment provide no evidence that sediment contamination with TNT or SNFC compounds is a causative factor for the induction of gonad malformations in Lake Thun whitefish.