Volatiles associated with scolytus scolytus beetles on English elm

Summary -Multistriatin, 4-methyl-3-heptanol and-cubebene, the components of the aggregation pheromone of Scolytus multistriatus are also associated with virgin female Scolytus scolytus on English elm, Ulmus procera.We thank Dr J. F. Grove for advice and encouragement, Mrs J. Allsop for technical assistance, Dr J. W. Peacock for authentic samples of multistriatin, 4-methyl-3-heptanol and-cubebene, and the Parks and Gardens Dept., Brighton Corporation, for supplies of English elm.     

Attraction ofScolytus scolytus (F.) to the components of Multilure,the aggregation pheromone ofS. multistriatus (Marsham) (Coleoptera: Scolytidae)

Summary The attraction ofS. scolytus to the components of Multilure is described. 4-Methyl-3-heptanol is an attractant which is synergised bya-cubebene. Multistriatin appears to be an inhibitor. A combination of 4-methyl-3-heptanol and cubeb oil is more effective as a bait forS. scolytus than Multilure.We thank Mr A. K. Hughes and Mr J. Boswell for their cooperation in allowing us to conduct experiments on Parham Estate; Mr D. Mobbs and Mr C. Thorne for the statistical analyses; Dr J. W. Peacock for samples of mixed isomers of multistriatin and distilled cubeb oil; Mrs J. Allsop and Mr N. J. Fielding for technical assistance. We are grateful to Mr D. Bevan, Dr J. H. Borden, Dr J. F. Grove and Prof. A. W. Johnson for their interest and encouragement.     

Direct charging of tRNA(CUA) with pyrrolysine in vitro and in vivo

Pyrrolysine is the 22nd amino acid. An unresolved question has been how this atypical genetically encoded residue is inserted into proteins, because all previously described naturally occurring aminoacyl-tRNA synthetases are specific for one of the 20 universally distributed amino acids. Here we establish that synthetic L-pyrrolysine is attached as a free molecule to tRNA(CUA) by PylS, an archaeal class II aminoacyl-tRNA synthetase. PylS activates pyrrolysine with ATP and ligates pyrrolysine to tRNA(CUA) in vitro in reactions specific for pyrrolysine. The addition of pyrrolysine to Escherichia coli cells expressing pylT (encoding tRNA(CUA)) and pylS results in the translation of UAG in vivo as a sense codon. This is the first example from nature of direct aminoacylation of a tRNA with a non-canonical amino acid and shows that the genetic code of E. coli can be expanded to include UAG-directed pyrrolysine incorporation into proteins.