Abstract
The Sex Ratio Organism (SRO), a kind of spiroplasma parasitic to the fruit fly Drosophila, proliferated transiently in a primary cell culture from SRO-infected fly embryos. The density of SRO increased more than a hundred times the initial density, reaching 6×105 per μ1 in 3-4 weeks. The serum concentration in the culture media was found to be critical to the SRO proliferation. SRO proliferated in vitro were capable of killing male embryos following their injection into female adult hosts, indicating normal SRO activity in vivo.
