FIG. 4.
Mouse lethality assay results with trypsinized or nontrypsinized genotype D supernatants. The front row shows mouse lethality results with a nontrypsinized aliquot of vegetative culture supernatants prepared from 21 different genotype D isolates (see Table 2 for their phenotype). The back row depicts mouse lethality results for the same genotype D vegetative supernatants after trypsinization. Numbers at top of supernatants 1, 5, and 18 had lethality levels too large to depict on this graph. The results shown are the mean of two independent determinations. Note that culture supernatants were arbitrarily assigned numbers 1 to 21 to avoid possible misuse by identifying genotype D isolates producing highly lethal supernatants. Genotype D isolates producing supernatants 1 to 4, 7 to 12, 14, and 18 to 20 are animal disease isolates from the BW collection; isolates producing supernatants 13, 17, and 21 are recent North American animal disease genotype D isolates provided by Glenn Songer; and the remaining supernatants (5, 6, and 16) were from animal disease genotype D isolates obtained from miscellaneous sources.