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In vivo investigations of catfish olfactory receptor neurons (ORNs) were previously limited to studying responses of spontaneously active cells. The olfactory organ, however, also contains ORNs that lack spontaneous activity and respond to amino acids. To record electrical activity of ORNs that were inactive prior to stimulation, we bathed the olfactory organ with low conductive, highly purified water that reduces shunting and enables detection of action potentials from ORNs distant to the electrode. After stimulation with amino acids, these ORNs elicited either phasic-tonic or tonic only activities. The spike frequency of the phasic activity consisted of transient frequencies up to 108 Hz that lasted 2 amino acids that included l-norvaline. In 29 of 31 neurons responding to >1 amino acid, the duration of the responses to the most stimulatory amino acid was at least double compared to that to the other amino acids. The amplitude of electro-olfactogram (EOG) correlated significantly with the number of ORNs activated by the same amino acids confirming that the EOG represents the sum of ORN receptor potentials.

From a certain number of females, eggs were collected during their first and second spawning. Body mass at spawning (MPlm) and absolute fecundity (PAbs) was registered for each female. On the basis of these data the relative fecundity was calculated (PRel). For each female 50 eyed eggs as well as 50 offspring at different stages of growth were individually weighted. Weightings were done 11 days (T1), 6 weeks (T2) and 10 weeks (T3) after hatching. By such procedure mean weight of the eggs (MIker) and the mean body mass of alevins attained at T1, T2 in T3 (MRib1, MRib2 and MRib3) were obtained. The statistical model of partial regression including PRel and MIkeras independent variables was used to evaluate the influence of MIker on MRib1, MRib2 and MRib3. Results indicate that from heavier eggs heavier larvaeare hatched. Nevertheless, the influence of egg weight on body mass is only short termed. Partial regression coefficient of MIker on MRib3 is not statistically significant regardless whether relation between eggs and alevins at first or second spawning is observed. According to our results it is suggested that eggs collected at first spawning should not be discarded even they appear to be too small for production. At age of 10 weeks after hatching, average siye of alevins hatched from small eggs collected at first spawning did not to essentially differ from average size of alevins hatched from large eggs collected at second spawning. Od kalifornijskih postrvi iste plemenske jate smo pridobili ikre v prvi in drugi drsti. Za vsako samico smo pri vsaki od drsti določili maso telesa (MPlm) ter absolutno plodnost (PAbs). Na podlagi teh podatkov smo izračunali relativno plodnost (PRel). Od vsake plemenke smo individualno stehtali 50 iker v fazi iker z očmi, ter tri vzorce po 50 potomcev v različnih fazah rasti. Potomce smo tehtali 11 dni po izvalitvi (T1), nato pa še 6 tednov (T2) ter 10 tednov po izvalitvi (T3). Na ta način smo dobili podatke o povprečni masi iker (MIker) ter podatke o masah potomcev pri tehtanju T1, T2 in T3 (MRib1, MRib2 in MRib3). Na podlagi teh podatkov smo s statističnim modelom parcialne regresije, ki je kot neodvisni spremenljivki vključeval relativno plodnost in povprečno maso iker, ocenili vpliv MIker na MRib1, MRib2 in MRib3. Rezultati kažejo, da se iz težjih iker izvalijo teje larve. Vpliv MIker je relativno kratek, saj parcialni regresijski koeficient MIker na MRib3 ni statistično značilen ne pri ikrah iz prve ne pri ikrah iz druge drsti. Rezultati kažejo, da je za produkcijo smiselno uporabljati tudi ikre iz prvi drsti, čeprav so majhne. Deset tednov po izvalitvi se povprečna masa rib, izvaljenih iz majhnih iker, pridobljenih pri prvi drsti, ne razlikuje bistveno od povprečne mase rib, izvaljenih iz večjih iker, pridobljenih v drugi drsti.

The pattern of diel vertical migration and the trophic interactions of moon jelly (Aurelia sp.) were investigated in the sea lake of Mljet Island (Adriatic Sea) where this scyphomedusa is present throught the year...

Observations of stenophore species were made in the Gulf of Trieste between 2003 and 2006. We examined native ctenophore species with special attention to representatives of the orders Lobata and Beroida...

Planktonic cnidarians in the open southern Adriatic Sea: a comparison of historical and recent data