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Recognition of alkali-labile gangliosides by two- dimensional thin-layer chromatography and immunohistochemical localization after alkali treatment from the brain of two poikilothermic fish species

The relative content of alkali-labile gangliosides and distribution of these sphingolipids were examined in the brain of two poikilothermic fish species: eurythermic common carp (Cyprinus carpio) and stenothermic rainbow trout (Oncorhynchus mykiss). Animals were subjected to seasonal temperature fluctuations in their natural ecosystem. In order to separate alkali-labile gangliosides from alkali-stabile we have performed two- dimensional thin layer chromatography with ammonia treatment. Rainbow trout brain in winter showed large quantities of alkali-labile ganglioside (40.56%), while in the summer established in a smaller proportion (33.14%). Common carp brain showed approximately equal amounts of alkali-labile ganglioside in winter (30.86%) and summer (30.88%). In this research for the first time immunohistochemical staining of sections previously treated with ammonium alkali vapors in order to determine the distribution of alkali-labile gangliosides in tissues was performed. Our results indicates that the epitopes recognized by the monoclonal antibody in alkali- labile gangliosides were changed with ammonia treatment and only recognition of alkali-stabile gangliosides was present. We assumed that the alkali treatment causes changes in ester bonds in epitope of alkali-labile gangliosides and therefore antibody does not recognize them. Imunohistochemical staining of sections previously treated with ammonium vapors gave insight into the distribution of alkali-stabile gangliosides and comparison with the positive reaction in untreated samples insight into the distribution of alkali- labile gangliosides. Content and distribution of brain alkali-labile gangliosides changes differently in common carp and rainbow troutMost pronounced changes were those where anti-GT1b staining after alkali treatment of rainbow trout forebrain was used. During the winter GT1b ganglioside has a higher proportion of alkali- labile gangliosides in telencephalon and optic tectum, while a smaller portion is visible in the valvula and cerebellum. During the summer there was a change in the distribution and ganglioside GT1b has a lower proportion of alkali-labile gangliosides in the telencephalon and optic tectum, and a larger in the valvula and cerebellum. The percentage of alkali-labile gangliosides was found to be related to the ecophysiological state of thermal adaptation.

alkali-labile gangliosides ; two-dimensional thin-layer chromatography ; immunohistochemical localization ; rainbow trout ; common carp

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