Percorrer por autor "Kolmakov, Nikolai N."
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- Analysis of the goldfish Carassius auratus olfactory epithelium transcriptome reveals the presence of numerous non-olfactory GPCR and putative receptors for progestin pheromonesPublication . Kolmakov, Nikolai N.; Kube, M.; Reinhardt, Richard; Canario, Adelino V. M.The goldfish (Carassius auratus) uses steroids and prostaglandins as pheromone cues at different stages of the reproductive cycle to facilitate spawning synchronization. Steroid progestin pheromone binding has been detected in goldfish olfactory membranes but the receptors responsible for this specific binding remain unknown. In order to shed some light on the olfactory epithelium transcriptome and search for possible receptor candidates a large set of EST from this tissue were analysed and compared to and combined with a similar zebrafish (Danio rerio) resource.
- Effect of acute copper sulfate exposure on olfactory responses to amino acids and pheromones in goldfish (Carassius auratus)Publication . Kolmakov, Nikolai N.; Hubbard, Peter; Lopes, Orlando; Canario, Adelino V. M.Exposure of olfactory epithelium to environmentally relevant concentrations of copper disrupts olfaction in fish. To examine the dynamics of recovery at both functional and morphological levels after acute copper exposure, unilateral exposure of goldfish olfactory epithelia to 100 μM CuSO4 (10 min) was followed by electro-olfactogram (EOG) recording and scanning electron microscopy. Sensitivity to amino acids (L-arginine and L-serine), generally considered food-related odorants, recovered most rapidly (three days), followed by that to catecholamines(3-O-methoxytyramine),bileacids(taurolithocholic acid) and the steroid pheromone, 17,20 -dihydroxy-4-pregnen- 3-one 20-sulfate, which took 28 days to reach full recovery. Sensitivity to the postovulatory pheromone prostaglandin F2R had not fully recovered even at 28 days. These changes in sensitivity were correlated with changes in the recovery of ciliated and microvillous receptor cell types. Microvillous cells appeared largely unaffected by CuSO4 treatment. Cilia in ciliated receptor neurones, however, appeared damaged one day post-treatment and were virtually absent after three days but had begun to recover after 14 days. Together, these results support the hypothesis that microvillous receptor neurones detect amino acids whereas ciliated receptor neurones were not functional and are responsible for detection of social stimuli (bile acidsandpheromones).Furthermore, differences in sensitivity to copper may be due to different transduction pathways in the different cell types.
- Sex steroids and oocyte maturation in the sterlet (Acipenser ruthenus L.)Publication . Semenkova, T.; Canario, Adelino V. M.; Bayunova, L.; Couto, Elsa; Kolmakov, Nikolai N.; Barannikova, I.Sturgeon oocytes, like those of other vertebrates, are arrested in early meiosis and require a steroid or steroids to trigger meiosis resumption or maturation. The identity of the maturation-inducing steroid in sturgeons has present study was designed to investigate in sterlet the follicular secretion and relative blood changes of free and conjugated 17,20βP, 20βS and of the androgens T, 11KT, in response to hormonal treatment and to determine the relative potencies of the progestagens, 17,20β-P, 20βS, P4 and S, in inducing oocyte final maturation in vitro.