Browsing by Subject "DANIO-RERIO"

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  • Semenova, Svetlana; Rozov, Stanislav; Panula, Pertti (2017)
    Catechol-O-methyltransferase (COMT; EC 2.1.1.6) is an enzyme with multiple functions in vertebrates. COMT methylates and thus inactivates catecholamine neurotransmitters and metabolizes xenobiotic catechols. Gene polymorphism rs4680 that influences the enzymatic activity of COMT affects cognition and behavior in humans. The zebrafish is widely used as an experimental animal in many areas of biomedical research, but most aspects of COMT function in this species have remained uncharacterized. We hypothesized that both comt genes play essential roles in zebrafish. Both comt-a and comt-b were widely expressed in zebrafish tissues, but their relative abundance varied considerably. Homogenates of zebra fish organs, including the brain, showed enzymatic COMT activity that was the highest in the liver and kidney. Treatment of larval zebrafish with the COMT inhibitor Ro41-0960 shifted the balance of catecholamine metabolic pathways towards increased oxidative metabolism. Whole-body concentrations of dioxyphenylacetic acid (DOPAC), a product of dopamine oxidation, were increased in the inhibitor treated larvae, although the dopamine levels were unchanged. Thus, COMT is likely to participate in the processing of catecholamine neurotransmitters in the zebrafish, but the inhibition of COMT in larval fish is compensated efficiently and does not have pronounced effects on dopamine levels. (C) 2017 Elsevier Inc. All rights reserved.
  • Haverinen, Jaakko; Hassinen, Minna; Dash, Surjya Narayan; Vornanen, Matti (2018)
    Calcium channels are necessary for cardiac excitation-contraction (E-C) coupling, but Ca2+ channel composition of fish hearts is still largely unknown. To this end, we determined transcript expression of Ca2+ channels in the heart of zebrafish (Danio rerio), a popular model species. Altogether, 18 Ca2+ channel alpha-subunit genes were expressed in both atrium and ventricle. Transcripts for 7 L-type (Ca(v)1.1a, Ca(v)1.1b, Ca(v)1.2, Ca(v)1.3a, Ca(v)1.3b, Ca(v)1.4a, Ca(v)1.4b), 5 T-type (Ca(v)3.1, Ca(v)3.2a, Ca(v)3.2b, Ca(v)3.3a, Ca(v)3.3b) and 6 P/Q-, N - and R-type (Ca(v)2.1a, Ca(v)2.1b, Ca(v)2.2a, Ca(v)2.2b, Ca(v)2.3a, Ca(v)2.3b) Ca2+ channels were expressed. In the ventricle, T-type channels formed 54.9%, L-type channels 41.1% and P/Q-, N- and R-type channels 4.0% of the Ca2+ channel transcripts. In the atrium, the relative expression of T-type and L-type Ca2+ channel transcripts was 64.1% and 33.8%, respectively (others accounted for 2.1%). Thus, at the transcript level, T-type Ca2+ channels are prevalent in zebrafish atrium and ventricle. At the functional level, peak densities of ventricular T-type (I-CAT) and L-type (I-CAL) Ca2+ current were 6.3 +/- 0.8 and 7.7 +/- 0.8 pA pF(-1), respectively. I-CAT mediated a sizeable sarcolemmal Ca2+ influx into ventricular myocytes: the increment in total cellular Ca2+ content via I-CAT was 41.2 +/- 7.3 mu mol l(-1), which was 31.7% of the combined Ca2+ influx (129 mu mol l(-1)) via I(CAT )and I(CAL)( ()88.5 +/- 20.5 mu mol l(-1)). The diversity of expressed Ca2+ channel genes in zebrafish heart is high, but dominated by the members of the T-type subfamily. The large ventricular I(CAT )is likely to play a significant role in E-C coupling.
  • Bolotovskiy, Aleksey A.; Levina, Marina A.; DeFaveri, Jacquelin; Merila, Juha; Levin, Boris A. (2018)
    The three-spined stickleback Gasterosteus aculeatus is an important model for studying microevolution and parallel adaptation to freshwater environments. Marine and freshwater forms differ markedly in their phenotype, especially in the number of lateral plates, which are serially repeated elements of the exoskeleton. In fishes, thyroid hormones are involved in adaptation to salinity, as well as the developmental regulation of serially repeated elements. To study how thyroid hormones influence lateral plate development, we manipulated levels of triiodothyronine and thiourea during early ontogeny in a marine and freshwater population with complete and low plate phenotypes, respectively. The development of lateral plates along the body and keel was heterochronic among experimental groups. Fish with a low dosage of exogenous triiodothyronine and those treated with thiourea exhibited retarded development of bony plates compared to both control fish and those treated with higher a triiodothyronine dosage. Several triiodothyronine-treated individuals of the marine form expressed the partial lateral plate phenotype. Some individuals with delayed development of lateral plates manifested 1-2 extra bony plates located above the main row of lateral plates.
  • Garcia-Gonzalez, Judit; Brock, Alistair J.; Parker, Matthew O.; Riley, Riva J.; Joliffe, David; Sudwarts, Ari; Teh, Muy-Teck; Busch-Nentwich, Elisabeth M.; Stemple, Derek L.; Martineau, Adrian R.; Kaprio, Jaakko; Palviainen, Teemu; Kuan, Valerie; Walton, Robert T.; Brennan, Caroline H. (2020)
    To facilitate smoking genetics research we determined whether a screen of mutagenized zebrafish for nicotine preference could predict loci affecting smoking behaviour. From 30 screened F-3 sibling groups, where each was derived from an individual ethyl-nitrosurea mutagenized F-0 fish, two showed increased or decreased nicotine preference. Out of 25 inactivating mutations carried by the F-3 fish, one in the slit3 gene segregated with increased nicotine preference in heterozygous individuals. Focussed SNP analysis of the human SLIT3 locus in cohorts from UK (n=863) and Finland (n=1715) identified two variants associated with cigarette consumption and likelihood of cessation. Characterisation of slit3 mutant larvae and adult fish revealed decreased sensitivity to the dopaminergic and serotonergic antagonist amisulpride, known to affect startle reflex that is correlated with addiction in humans, and increased htr1aa mRNA expression in mutant larvae. No effect on neuronal pathfinding was detected. These findings reveal a role for SLIT3 in development of pathways affecting responses to nicotine in zebrafish and smoking in humans.