Collaborative studies were performed to develop a functional assay for fish
-killing activity produced by P. fiesteria piscicida. Eight cell lines were
used to screen organic fractions and residual water fraction by using a 3-
[4,5-dimethylthiazol-(2-4)]-diphenyltetrazolium bromide cytotoxicity assay.
Diethyl ether and a residual water fraction were cytotoxic to several cell
lines including rat pituitary (GH(4)C(1)) cells. Residual water as well as
preextracted culture water containing P. piscicida cells induced c-fos-luc
iferase expressed in GH(4)C(1) cells with a rapid time course of induction
and sensitive detection. The reporter gene assay detected activity in toxic
isolates of P. piscicida from several North Carolina estuaries in 1997 and
1998 and may also be suitable for detecting toxic activity in human and an
imal serum.