title: A biochemical comparison of proteases from pathogenic naegleria fowleri and non-pathogenic Naegleria gruberi.
abstract: Naegleria fowleri is the etiologic agent of primary amoebic meningoencephalitis (PAM). Proteases have been suggested to be involved in tissue invasion and destruction during infection. We analyzed and compared the complete protease profiles of total crude extract and conditioned medium of both pathogenic N. fowleri and non-pathogenic Naegleria gruberi trophozoites. Using SDS-PAGE, we found differences in the number and molecular weight of proteolytic bands between the two strains. The proteases showed optimal activity at pH 7.0 and 35 degrees C for both strains. Inhibition assays showed that the main proteolytic activity in both strains is due to cysteine proteases although serine proteases were also detected. Both N. fowleri and N. gruberi have a variety of different protease activities at different pH levels and temperatures. These proteases may allow the amoebae to acquire nutrients from different sources, including those from the host. Although, the role of the amoebic proteases in the pathogenesis of PAM is not clearly defined, it seems that proteases and other molecules of the parasite as well as those from the host, could be participating in the damage to the human central nervous system.
authors.affiliation: Department of Cell Biology, Center for Research and Advanced Studies, México City 07360, Mexico. serranolunajesus@yahoo.com.mx
authors.forename: Jesús
authors.initials: J
authors.lastname: Serrano-Luna
authors.forename: Isaac
authors.initials: I
authors.lastname: Cervantes-Sandoval
authors.forename: Victor
authors.initials: V
authors.lastname: Tsutsumi
authors.forename: Mineko
authors.initials: M
authors.lastname: Shibayama
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002384:Catalysis / Q000187:drug effects; D003546:Cysteine Endopeptidases / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005780:Gelatin / Q000378:metabolism; D009253:Naegleria / Q000201:enzymology*; D016848:Naegleria fowleri / Q000201:enzymology; D010447:Peptide Hydrolases / Q000378:metabolism*; D011480:Protease Inhibitors / Q000494:pharmacology; D011522:Protons; D015800:Protozoan Proteins / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D011480:Protease Inhibitors; D011522:Protons; D015800:Protozoan Proteins; D005780:Gelatin; D010447:Peptide Hydrolases; D003546:Cysteine Endopeptidases