Developmental changes of ganglioside compositions and biosyntheses in rat bone marrow cells, spleen and thymus

Studies on developmental changes of ganglioside synthesis and compositions were carried out using rat bone marrow cells, spleen and thymus. Ganglioside synthesis was studied by assaying sialyltransferase for GM3 synthesis and GM1b synthesis. In bone marrow cells, peaks of both enzyme activities occurred coincidentally in 2- to 5-week-old rats. In spleen, the highest activities of these enzymes were observed in one-week-old rats. GM1b synthesis in the thymus was almost constant after birth, but GM3 synthesis could not be detected at any age examined. Developmental changes of gangliosides in these tissues were analyzed by thin layer chromatography. Gangliosides corresponding to GM1b and GM3 were recognized in each tissue. The ganglioside content of the bone marrow cells increased in 2- to 5-week-old rats. Ganglioside corresponding to GM1b was isolated from the bone marrow cells, and its structure was confirmed to be the same as that of GM1b by sequential hydrolysis of the ganglioside with glycosidases. GM3 was a predominant ganglioside in newborn rat spleen. Ganglioside content in the spleen increased during 2-5 weeks after birth and became constant after 9 weeks. In the thymus, more than 10 different gangliosides were discriminated, but significant changes of ganglioside pattern with the progress of development could not be observed. The developmental change of the ganglioside composition coincided well with the change of sialyltransferase activities.