Role of microfilaments and microtubules in the invasion of EPC cells by Aeromonas hydrophila

The influence of the cytoskeleton on the invasion of Aeromonas hydrophila strain AhJ-1, isolated from diseased fish, in the monolayer cell of epithelioma papillosum cells of carp (EPC) was evaluated by the recovery of gentamicin-resistant bacteria from Triton X-100 cell lysates. The depolymerization of microfilaments (MF) by cytochalasin B and D inhibited the uptake of A. hydrophila in a dose-dependent manner and that of microtubules (MT) by colchicines and nocodazole did not affect the invasion of A. hydrophila in EPC cells significantly. The invasion frequency decreased approximately 62% with the addition of 0.1 microg/ml cytochalasin D and nearly 86% by the addition of 5.0 microg/ml. Invasion decreased approximately 49% and 83% by addition of cytochalasin B in a concentration of 2.5 microg/ml and 10.0 microg/ml. Colchicine and nocodazole, inhibitors of MT formation appears to have little effect on the invasion of EPC cells by strain Ah J-1. Thus MF formation, but not MT formation seems to play an important role in the internalization of A. hydrophila J-1.