The comparison of rhapidosomes and defective bacteriophage particles from Aquaspirillum intersonii.

Aquaspirillum itersonii spontaneously produces rhapidosomes. These structures, which are found throughout the cell cycle, are compared with the defective bacteriophage particles that can be induced by mitomycin C treatment (0.5 microgram/mL). The rhapidosomes are composed of three proteins (MW 63 000, 23 500, and 15 000). The defective bacteriophage particles are composed of two proteins (MW 50 000 and 17 500). The defective bacteriophage particles do not react with anti-rhapidosomal protein antiserum. These results indicate that the rhapidosome are not polysheaths of the defective bacteriophage particles inducible in this organism as earlier proposed in the literature. It is concluded that the rhapidosomes of A. itersonii are an assembly of three proteins that are distributed in the cytosol after synthesis and are present at all times in the growth cycle.