Tail Synthesis Research Articles

Fine structure of bacteriophage-infected Myxococcus xanthus: I. The lytic cycle in vegetative cells

The virulent bacteriophage MX-1 lytic cycle in vegetative cells of Myxococcus xanthus has been followed by fine structure studies of thin sections. Adsorption and much of the visible sequence of events in the synthesis of progeny phage particles occurs at or near the poles of infected cells. Cell morphology changes markedly during the latent period. The nuclear body changes form, aggregates of cytoplasmic components appear at the poles, and the cells gradually become spherical. Incomplete phage capsids appear to be closely associated with ribosomes. Free tails are not observed in the infected cells. It appears that tail synthesis occurs by addition of tail proteins to completed heads. Ribosomes were observed to be closely associated with the growing tails.

The production of inactive phage P22 particles following induction

Using an in vitro system for tail attachment, it is demonstrated that following ultraviolet (UV) induction of Salmonella typhimurium LT2 (P22) most of the particles formed lack a functional tail. This effect is found at all temperatures studied, but is more pronounced at temperatures of 37° and above. Similar results are described for thermal and spontaneous induction. Tailless particles are found following infection only at temperatures of 42° and above. Temperature pulse experiments on UV-induced lysogens suggest that late in the growth cycle tail synthesis is inhibited by high temperature. There is also an earlier temperature-sensitive step, which probably causes the production of inactive heads at 40°.