The Action of Virginiamycin on Nucleic Acid and Protein Synthesis in Bacillus subtilis Infected with Bacteriophage 2C

Abstract

S U M M A R YAddition of virginiamycin M or S before the virulent phage 2 C prevented Bacillus subtilis from lysing, and this effect was increased Ioo-fold by simultaneous addition of both factors. When the antibiotics were administered at the end of the eclipse phase, the viral cycle was shortened by virginiamycin S, prolonged by factor M and halted by the two inhibitors together. Virginiamycins also prevented the accumulation of phage particles by inhibiting the synthesis of viral precursors during the eclipse period as well as during the maturation phase.Synthesis of cellular macromolecules was decreased (not suppressed) in Bacillus subtilis after infection with phage 2C, and the degree of repression was a function of the input multiplicity. Viral inhibition of thymidine and uridine incorporation into host DNA and RNA was prevented when virginiamycin was added before infection but unaffected when addition was made at the end of the eclipse phase. Virus and virginiamycin had additive non-overlapping effects on protein synthesis. Moreover, Virginiamycins interfered with the function, not the formation, of RNA pulse-labelled after infection, and prevented its decay.It can be concluded that virginiamycin blocks (a) the preferential translation of viral message, (b) the mechanism by which virus halts host-macromolecule formation, and (c) the synthesis of viral DNA. This can be explained by an inhibitory action of virginiamycin on the synthesis and function of virus-dictated proteins.

Cloning and characterization of transcriptional promoters fromBacillus subtilisphage 2C

“…both synthesized during the first 13 min of the infection cycle, whereas preferential transcription of viral genes occurs at later times (Cocito 1969(Cocito ,1974. Temporal gene expression in hmUra phages, mainly studied in SPOl (and SP82), is regulated by a cascade of transcriptional initiation factors.…”

An analysis of sponge genomes

“…The relationship of Schildkraut et al (1962), q=(GCÂ0.098)/100+1.66, was used to convert buoyant densities into GC levels. Bacillus subtilis phage 2C DNA (q m =1.742 g/cm 3 ) was used as a density marker (Cocito, 1969). Fig.…”

Cloning of DNA segments of phage 2C, which allows autonomous plasmid replication in Bacillus subtilis

“…Preparation of phage 2 C and viral DNA Composition of growth media, and procedures for production and purification of phage 2C by buoyant density centrifugation, and for extraction and analysis of 2C DNA have been previously described [16,24,251.…”

“…[23] were used for transformation experiments with plasmid DNA. Bacteria were grown as previously described [24]. L broth, casamino (acid hydrolysate of casein) and yeast extract were from Difco Laboratories (Detroit, MI, USA).…”