Efekti subhroničnog izlaganja zebrice, danio rerio sintetičkom mošusu

Policiklična jedinjenja sintetičkog mošusa su veoma rasprostranjena i koriste se u velikim količinama kao miris u proizvodima široke potrošnje. Zbog njihove česte upotrebe i otpuštanja mirisa, ova jedinjenja su postala prisutna svuda u životnoj sredini. Toksikološka istraživanja su potvrdila da jedinjenje mošusa predstavlja opasnost za vodene ekosisteme. Cilj ovog istraživanja bio je da se ocene efekti subhroničnog izlaganja sintetičkom mošusu tonalidu na rast riba i odgovore na oksidativni stress kod zebrice (Danio rerio). Test rasta kod mlađi zebrice izvršen je prema OECD metodu broj 215. U toku 28 dana, riba stara 30 dana je bila izložena koncentraciji tonalida (50; 500; 5.000 and 50.000 ng/l). Na kraju eksperimenta, sve ribe su žrtvovane, izmerene, određena je njihova specifična prosečna stopa rasta po tanku, a selektivni oksidativni stress markeri su analizirani u homogenatu celog tela (glutation S-transferaze, glutation reduktaze, glutation peroksidaze, katalaze i lipidne peroksidaze). U našem ekperimentu, nismo pronašli značajne razlike između kontrolne i eksperimentalne grupe u specifičnom prirastu, telesnoj težini i dužini. Međutim, primetili smo značajne promene kod većine oksidativnih stres markera naročito kod eksperimentalne grupe koja je bila izložena najvećoj koncentraciji mošusa (tonalida). U poređenju sa kontrolnom grupom, značajna povećanje je konstatovano u aktivnostima glutation S-transferaze (za koncentracije – 5.000 i 50.000 ng/l) i kataze (za koncentracije – 500, 5.000 i 50.000 ng/l). Sa druge strane, primećeno je značajno smanjenje aktivnosti glutation peroksidaze (za koncentraciju – 500 ng/l) u poređenju sa kontrolnom grupom. Nisu konstatovane promene u aktivnosti glutation reduktaze i nivou lipidne peroksidaze u poređenju sa kontrolnom grupom. Naši rezultati pokazuju da izlaganje zebrice tonalidinu ima značajan uticaj na oksidativne stres markere i enzime za detoksifikaciju. Promene u aktivnostima antioksidantnih enzima se mogu tumačiti kao adaptivni odgovor koji bi zaštitio organizam ribe od toksičnosti prouzrokovane tonalidinom

Antimycobacterial and Photosynthetic Electron Transport Inhibiting Activity of Ring-Substituted 4-Arylamino-7-Chloroquinolinium Chlorides

In this study, a series of twenty-five ring-substituted 4-arylamino-7-chloroquinolinium chlorides were prepared and characterized. The compounds were tested for their activity related to inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts and also primary in vitro screening of the synthesized compounds was performed against mycobacterial species. 4-[(2-Bromophenyl)amino]-7-chloroquinolinium chloride showed high biological activity against M. marinum, M. kansasii, M. smegmatis and 7-chloro-4-[(2-methylphenyl)amino]quinolinium chloride demonstrated noteworthy biological activity against M. smegmatis and M. avium subsp. paratuberculosis. The most effective compounds demonstrated quite low toxicity (LD50 \u3e 20 μmol/L) against the human monocytic leukemia THP-1 cell line within preliminary in vitro cytotoxicity screening. The tested compounds were found to inhibit PET in photosystem II. The PET-inhibiting activity expressed by IC50 value of the most active compound 7-chloro-4-[(3-trifluoromethylphenyl)amino]quinolinium chloride was 27 μmol/L and PET-inhibiting activity of ortho-substituted compounds was significantly lower than this of meta- and para-substituted ones. The structure-activity relationships are discussed for all compound

25th annual computational neuroscience meeting: CNS-2016

The same neuron may play different functional roles in the neural circuits to which it belongs. For example, neurons in the Tritonia pedal ganglia may participate in variable phases of the swim motor rhythms [1]. While such neuronal functional variability is likely to play a major role the delivery of the functionality of neural systems, it is difficult to study it in most nervous systems. We work on the pyloric rhythm network of the crustacean stomatogastric ganglion (STG) [2]. Typically network models of the STG treat neurons of the same functional type as a single model neuron (e.g. PD neurons), assuming the same conductance parameters for these neurons and implying their synchronous firing [3, 4]. However, simultaneous recording of PD neurons shows differences between the timings of spikes of these neurons. This may indicate functional variability of these neurons. Here we modelled separately the two PD neurons of the STG in a multi-neuron model of the pyloric network. Our neuron models comply with known correlations between conductance parameters of ionic currents. Our results reproduce the experimental finding of increasing spike time distance between spikes originating from the two model PD neurons during their synchronised burst phase. The PD neuron with the larger calcium conductance generates its spikes before the other PD neuron. Larger potassium conductance values in the follower neuron imply longer delays between spikes, see Fig. 17.Neuromodulators change the conductance parameters of neurons and maintain the ratios of these parameters [5]. Our results show that such changes may shift the individual contribution of two PD neurons to the PD-phase of the pyloric rhythm altering their functionality within this rhythm. Our work paves the way towards an accessible experimental and computational framework for the analysis of the mechanisms and impact of functional variability of neurons within the neural circuits to which they belong

Biophysical models of neurons

Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi