Effects of Differentiation-Inducing Factor-1 (DIF-1) of Dictyostelium discoideum on Bacteria, Fungi, and an Influenza Virus.

Background & Aims : Differentiation-inducing factor-1 (DIF-1) is a small lipophilic substance that induces stalk cell differentiation in the cellular mold Dictyostelium discoideum. It has been shown that DIF-1 has an anti-tumor activity in mammalian cells. In the present study, we examined the effects of DIF-1 on the growth of some bacteria, fungi, and an influenza virus.Method : We used in vitro systems for the assay for growth of microorganisms.Results : DIF-1 did not show marked effect on the bacteria and fungi tested. Interestingly, DIF-1 inhibited viral plaque formation in its host Madin-Darby canine kidney (MDCK) cells in a dose dependent manner and IC50 was 18μM. DIF-1 also inhibited the growth of MDCK cells and IC50 was 30μM.Conclusions : These results indicate that DIF-1 or its analogs may be utilized as a tool for the analysis of virus functions.