Three new antineoplastic natural products, combretastatin
A-4, dolastatin 10 and halichondrin B, have been evaluated for
their antimicrotubule activity in Uromyces
appendiculatus urediniospore germlings using indirect
immunofluorescence microscopy. In control
germlings microtubules were abundant and mostly oriented
parallel to the longitudinal axis of the cell. The microtubule
cytoskeleton of germlings treated with
1·3×10−5M
(10 μg ml−1) dolastatin 10 and
4·5×10−5M
(50 μg ml−1) halichondrin B disrupted the
microtubule cytoskeleton resulting in the near elimination of
microtubule-associated fluorescence. Combretastatin A-4 was less
effective, requiring a concentration of
3·2×10−3M
(1·0 mg ml−1) to disrupt the
microtubule cytoskeleton. These effective doses are
consistent with previously examined antimicrotubule agents
(e.g. nocodazole, griseofulvin, vincristine sulphate,
demecolcine).
