The pathogenic O1 Amazonia variant of Vibrio cholerae
has been shown previously to have a cytotoxin acting on
cultured Vero and Y-1 cells, and to lack important virulence
factors such as the cholera toxin (Coelho et al. 1995a). This
study extends the molecular analysis of the Amazonia strains,
detecting the presence of the toxR gene, with a very
similar sequence to that of the El Tor and classical biotypes.
The outer membrane proteins are analyzed, detecting a variation
among the group of Amazonia strains, with three different
patterns found. As a by-product of this work a polymerase chain
reaction fragment was sequenced, reading part of the sequence of
the Lon protease of the Amazonia strains. This gene was not
previously described in V. cholerae, but its sequence is
present in the TIGR database specific for this species.