Filamentous bacterial viruses. VII. Inhibition of fd deoxyribonucleic acid synthesis after a temperature jump into protein-synthesis inhibitors.

Synthesis of fd deoxyribonucleic acid (DNA) was stopped by transferring infected bacteria from 32 C into chloramphenicol or serine hydroxamate at 42 C, but not by addition of these antibiotics at 32 C, and not by a temperature change in the absence of antibiotics. The inhibition of fd DNA synthesis by serine hydroxamate at 42 C was reversed by excess serine. The ability to synthesize fd DNA at 42 C in chloramphenicol was rescued by delaying the addition of chloramphenicol for a few minutes after the transfer from 32 to 42 C.

Filamentous bacterial viruses. VI. Role of fd gene 2 in deoxyribonucleic acid replication.

Functional gene 2 product was found to be necessary for fd deoxyribonucleic acid (DNA) synthesis throughout the life cycle of the virus. Bacteria which had been infected with a temperature-sensitive gene 2 mutant ceased to make virus-specific DNA when transferred to restrictive conditions at any time after infection, although current rounds of replication were completed.

Filamentous bacterial viruses. V. Asymmetric replication of fd duplex deoxyribonucleic acid.

Short pulses (30 sec at 32 C) of (3)H-thymidine were found primarily in the viral strands of replicating fd deoxyribonucleic acid (DNA), even at a time when most DNA being synthesized was duplex DNA. Much of the labeled viral strand DNA was longer than unit length, but some was shorter than unit length. Most of the corresponding complementary-strand DNA was recovered in closed supercoiled duplex molecules, even for short pulses; the remainder of the complementary-strand DNA was found in replicative intermediates in pieces shorter than unit length.

Filamentous bacterial viruses. IV. Fate of the infecting parental single-stranded deoxyribonucleic acid.

Some of the infecting fd single-stranded viral deoxyribonucleic acid (DNA) molecules were found to be degraded after having initiated infection. The degradation products were reused for synthesis of DNA, primarily bacterial. Degradation was most extensive when viral DNA was replicating.