The effect of axenic versus xenic culture conditions on the total and secreted proteolytic activity of Entamoeba histolytica strains
Spice, W.M.; Ackers, J.P.
Archives of Medical Research 23(2): 91-93
1992
ISSN/ISBN: 0188-4409 PMID: 1340330 Document Number: 388272
Proteolytic activity in lysates of 4 axenic and 5 xenic cultures of different strains of pathogenic Entamoeba histolytica, and in 5 non-pathogenic strains growing in xenic culture was measured. There was no significant difference in total proteolytic activity, using either gelatine or albumin as substrate, between the two sets of xenic cultures; however, the axenic pathogens had significantly higher levels of activity than the xenic pathogens, the levels appearing to correlate with virulence. An axenic strain (NIH 200) reassociated with mixed bacterial flora reverted to close to xenic levels of activity. There was no evidence of secretion of an elevated proportion of the total enzymic activity by pathogenic strains, and expression levels may owe more to culture conditions than to genotype.