No abstract

Using two complementary strategies for low-resolution Sl mapping, the global pattern of (bC31 transcription was studied after induction of thermoinducible (bC31 lysogens of Streptomyces coelicolor A3(2). A complex pattern of early transcripts was seen, with a peak of abundance at about 10 min post-induction. Nearly all of these transcripts were from DNA located to the right of the c (repressor) gene and to the left of the attP site: a region of about 14 kb. Early transcription was also observed immediately to the left of the c gene. The c gene itself was also induced, with an earlier expression peak (about 5 min post-induction). Primary late transcripts were generally relatively long, but degraded. They apparently corresponded to most of the 18 kb region to the left of the c gene. Some shorter and more persistent late transcripts corresponded to DNA close to or overlapping the cos site. Large late transcripts from a region close to the left-hand end of the (bC31 genome showed evidence of processing to more stable, smaller RNA species. A failure of older cultures (more than 12 h old) to be induced productively was correlated with a much longer period of early transcription, reduced late transcription, failure to synthesize a major virion protein, and failure to package (bC31 DNA. Moreover, heat treatment of the older lysogenic cultures did not result in the 6C31-dependerd shut-down of host rRNA transcription previously observed for young cultures (Rodriguez et al

:  Cutaneous warts, commonly seen in children and the immunosuppressed are socially distressing and are often resistant to traditional treatments. Here, we report an 11‐year‐old girl with bilateral florid verrucous lesions on her hands, feet and chin, which were refractory to a number of standard treatments including cryotherapy, cantharidin preparations, topical salicylic acid, surgical debulking techniques, oral Cimetidine, and topical and intralesional Cidofovir. As the disfiguring lesions had a marked adverse effect on her quality of life, a trial of IV Cidofovir was instituted. We administered five cycles of IV Cidofovir with a 1‐week interval between the first and second treatment, followed by 2‐week intervals thereafter. This regime was well tolerated and we report dramatic resolution of the lesions with persistent clearance 6 months after completion of the fifth infusion. Resolution of recalcitrant warts with IV Cidofovir has been reported in a limited number of cases. Our experience supports its efficacy in this setting, and to the best of our knowledge this is the first report of successful treatment of cutaneous warts with IV Cidofovir in a pediatric case.

A lysogen of Streptomyces coelicolor A3(2) containing a thermoinducible mutant of the temperate phage phi C31 (phi C31 cts1) was used to obtain synchronous phage development. Filter hybridization experiments indicated a marked reduction in rRNA synthesis after prophage induction. S1 nuclease mapping showed that transcription from each of the four promoters of one rRNA gene set (rrnD) was reduced to approximately the same extent, and that inhibition required protein synthesis. Crude preparations of RNA polymerase from induced lysogens had enhanced transcribing activity for phi C31 DNA which was lost upon further purification. The purified preparations were unimpaired in their ability to transcribe from the rrnD promoters in vitro and apparently unchanged in polypeptide composition. The factor(s) responsible for stimulating phage transcription, and possibly for inhibiting rRNA synthesis, may have been separated from the enzyme during purification.