RESUMO
Carbohydrates are an essential requirement of the culture medium in many cells. Axenic cultures of amebas require a concentration of 0.5 to 1.0 per cent glucose. The purpose of this work is to demonstrate possible differences on the carbohydrates requirements between pathogenic and nonpathogenic amebas strains. The experimental work was done in two phases: a) observation of the cultures growing at different concentrations of glucose in TP-S-1 medium (0, 0.25, 0.50, 1.0 and 2.0 g/100 ml), and b) the substitution of glucose by other carbohydrates: D-fructose; D-galactose; D-manitol, maltose, lactose, sucrose and soluble starch. Four axenic strains were used: Entamoeba histolytica HM-2:IMSS and HK-9:NIH; E. invadens PZ and E. moshkovskii FIC. Enumeration of cultured protozoa was determinated with the aid of an hemacytometer. The results obtained indicate no difference between pathogenic strains (HM-2, HK-9 and PZ), at the concentrations of glucose in the medium (0.5 g/100 ml), however FIC strain (unique non-pathogenic strain tested), had the highest growth when 0.25 per cent glucose was used. All strains supported without any significant difference in growth, the substitution of glucose by maltose and starch.