Cell-assisted culture of fastidious spiroplasmas: initial analysis of growth factors.

Half of the spiroplasmas observed microscopically in insects cannot be cultivated and are thus inaccessible to study. Media mixed with cultured insect cells have now been used to isolate two of these spiroplasmas--the sex-ratio organism (SRO) of Drosophila and the Colorado potato beetle spiroplasma (CPBS). Studies described herein indicate that at least one of the cell-supplied factors is involved in redox maintenance. A wide variety of insect cell culture systems were suitable for primary isolation of the CPBS. The SRO and CPBS were found to attach to insect cells in vitro.