Interaction between Naegleria fowleri and pathogenic Escherichia coli by mannose and changes in N. fowleri protease.

Naegleria fowleri can cause acute primary amoebic encephalitis. It is known that contact-dependent pathogenicity in free-living amoeba may be mediated through a carbohydrate-dependent pathway. In this study, the effect of mannose on the interaction between N. fowleri and pathogenic Escherichia coli O157:H7 and non-pathogenic E. coli DH5α was analyzed. In particular, the changes in proteases expressed by N. fowleri in response to mannose were analyzed. Unlike the conventional method, mannose was treated with N. fowleri for 1 h. The association between N. fowleri and E. coli O157:H7 treated with 50-mM and 100-mM mannose was significantly reduced by approximately 70.9% and 128.5%, respectively. E. coli O157:H7 invasion was reduced by about 10.8% by 100-mM mannose. Moreover, as a result of culturing N. fowleri invaded by E. coli O157:H7 for 24 h, E. coli O157:H7 also grew about 1.2 times in the group not treated with mannose. E. coli DH5α association was reduced by 25.7% by 100-mM mannose. On the other hand, there was almost no inhibitory effect by 100-mM glucose. In the analysis in which mannose bound to either N. fowleri or bacteria and affected the interaction, there was little effect on the interaction between N. fowleri and bacteria. In zymographic analysis, about 135-kDa and 75-kDa bands were observed by 50-mM and 100-mM mannose, and two bands were significantly increased by 100-mM mannose. This study suggests that mannose can be mediated in the contact-dependent pathway of N. fowleri and will serve as a basis for inducing changes in the protease of N. fowleri by other monosaccharides.

Production of a monoclonal antibody against a galactose-binding protein of Acanthamoeba castellanii and its cytotoxicity.

In this study, it was confirmed whether the galactose-binding protein (GBP) was present in Acanthamoeba castellanii, and its function on a target cell was confirmed by production of an antibody against the GBP. Since the genes for GBP have not yet been identified at all, the purification of GBP was done using galactose-beads from amoebial lysates, and monoclonal antibodies were produced using cell fusion. GBP was confirmed to have a size of about 35 kDa. After the third immunization with purified GBP in BALB/c mice, monoclonal antibody production was analyzed. The clone cultured before limiting dilution was named 2AB2 and showed the highest antibody titer in the culture supernatant of a 24-well plate. AF6 clone cultured after limiting dilution showed an antibody titer of 0.259 in a 75-T flask. Antibodies generated by collecting ascites by injecting monoclonal colonies into the abdominal cavity of mice were confirmed through gel analysis and were observed to belong to the isotype of the IgM having kappa chains. Since the cytotoxicity of A. castellanii was inhibited by about 26% by the monoclonal antibody against GBP, it was confirmed that the antibody against GBP had an inhibitory effect on cytotoxicity. This study was the first report on GBP isolated and purified from A. castellanii, and similarly to a mannose-binding protein (MBP), its involvement in contact-dependent cytotoxicity was demonstrated with monoclonal antibody production.

The clinical features of Korean patients with Duane's retraction syndrome.

PURPOSE: To describe the clinical features of Duane's retraction syndrome (DRS) in Korean patients. METHODS: We retrospectively analyzed the 78 DRS cases that presented to our department between 1995 and 2004. The clinical features investigated included sex distribution, laterality, type of presentation, deviation in primary position, anomalous vertical movements, face turn, amblyopia and anisometropia. RESULTS: There were 38 (48.7%) affected males and 40 (51.3%) females. Left eye predominance (83.3%) was observed, as was type I presentation (85.9%). Orthotropia was found to be the most common primary position in 46 cases (59.0%). Face turn in unilateral DRS was noted in 13 patients (17.1%). There were 6 cases (7.7%) with anisometropia and 4 (5.1%) with amblyopia. CONCLUSIONS: The clinical manifestations of DRS in our study were different from those of equivalent Caucasian studies yet similar to those previously reported for Asian groups. Racial and regional differences were noted, for which further research is needed to elaborate the reasons and mechanisms.