Short-chain fatty-acid-induced effects on the cell cycle in root meristems of Pisum sativum

Propionic acid and valeric acid at 1 m M reduced the mitotic index of root meristem cells of Pisum sativum to <1% after 12 h in aerated White's medium. After 12 h exposure to either acid, seedlings transferred to fresh medium resumed their normal mitotic index 12 h after transfer, with a burst of mitosis at 8 h. Exposure times of 8 h to either acid inhibited DNA synthesis, and nuclei released from either propionic or valeric acid inhibition were still unable to resume normal DNA synthesis after 12 h. Neither acid significantly altered the distribution of meristematic cells in G1 and G2 after 12 h. Propionic acid at 1 m M reduced the uptake of [¹⁴C]-leucin but conversion rates to protein were constant regardless of whether any acid was present. Another longer fatty acid, caprylic acid, at 1 m M did not significantly reduce the mitotic index nor did 1 m M benzoic acid, another organic acid. This information suggests that only the short-chain fatty acids, propionic acid and valeric acid, limit progression through the cell cycle by inhibiting DNA synthesis and arresting cells in G1 and G2 in a manner similar to butyric acid, a known cell arresting agent.