Association Between Naegleria fowleri and Bacteria, its Cytotoxicity and Protein Activity by Monosaccharides

Naegleria fowleri is a brain-eating amoeba that inhabits freshwater and causes acute primary amoebic encephalitis (PAME). Studies on the importance of monosaccharides for the contact-dependent mechanism of free-living amoeba have been reported. In this study, association tests were analyzed to understand the contact-dependent mechanism of N. fowleri trophozoites with bacteria by monosaccharides. In addition, the cytotoxicity and proteolytic activity of N. fowleri by monosaccharides were analyzed. Salmonella typhi association by 100 mM mannose was inhibited by about 217% compared to the monosaccharide untreated control. The association of pathogenic S. typhi was about 180% higher than that of nonpathogenic Escher¬ichia coli. However, galactose, another monosaccharide, did not show the inhibitory effect of mannose. The cytotoxicity of the 50mM and 100mM mannose-treated groups was inhibited by 35.9% and 59.4%, respectively (P<0.05). On the other hand, in the 100 mM group treated with galactose, cytotoxicity was in¬hibited by about 25.8%. The activity of N. fowleri trophozoites proteolytic enzyme was maximized by 100 mM mannose but had little effect by galactose at a concentration of 0 to 100 mM. Taken together, it was confirmed that the pathogen-host interaction could be mediated by monosaccharides and that mannose and galactose could act as important mediators for N. fowleri trophozoites even though the galactose-induced proteolytic enzyme activity of N. fowleri trophozoites was weak.