Barban and chlorpropham are common carbamate herbicides that disrupt mitosis by destabilizing plant microtubules. Tubulins, protein subunits of microtubules, in plant and animal cells are highly conserved through evolution. Plant and animal cells have been shown to possess similar microtubule structural proteins, microtubule binding proteins, and organizational proteins. These similarities suggest that herbicides targeting plant microtubules might also affect animal microtubules. Previous tubulin immunofluorescence microscopic studies of HeLa cells, a human cervical cancer cell line, have shown that barban is strongly cytoskeletotoxic and chlorpropham is weakly cytoskeletotoxic. Both barban and chlorpropham have been shown to disrupt mitosis and disorganize spindle apparatus formation in numerous types of mammalian cancer cells.

This investigation was undertaken to examine the effect of barban and chlorpropham on MRC-5 cells, a normal human fibroblast cell line, as well as on HeLa cells. A monoclonal antibody to α-tubulin, a microtubule specific protein, was used to probe the formation of spindle apparatuses in dividing cells.