We present a measurement of neutrino tridents, muon pairs induced by neutrino scattering in the Coulomb field of a target nucleus, in the Columbia-Chicago-Fermilab-Rochester neutrino experiment at the Fermilab Tevatron. The observed number of tridents after geometric and kinematic corrections, 37.0 ± 12.4, supports the standard-model prediction of 45.3 ± 2.3 events. This is the first demonstration of the W-Z destructive interference from neutrino tridents, and rules out, at 99% C.L., the V -A prediction without the interference.PACS numbers: 13.10.+q, 12.15.Ji, 14.80.Er, 25.30.Pt A neutrino trident is the scattering of a neutrino in the Coulomb field of a target nucleus (TV),

A high-statistics study by the Columbia-Chicago-Fermilab-Rochester Collaboration of opposite-sign dimuon events induced by neutrino-nucleon scattering at the Fermilab Tevatron is presented. A sample of 5044 v M and 1062 vv induced /i^/i 1 events with P^ > 9 GeV/c, P^2> 5 GeV/c, 30 < E v < 600 GeV, and

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The Staphylococcus aureus ermA gene, whose product confers resistance to the macrolide-lincosamidestreptogramin B family of antibiotics, is induced at the level of translation by nanomolar concentrations of erythromycin. Erythromycin also specffically stabilizes ermA transcripts, and the induced stabilization requires in-phase translation of at least one of two small leader peptides in the 5' leader region of the transcript. Erythromycin-induced mRNA stabilization was tested in three constructions in which the ermA transcript was elongated by making insertions at the ermA transcription start. Whereas mRNA downstream of the leader peptide is stabilized by erythromycin, mRNA upstream is not. In the presence of erythromycin, specific mRNA decay intermediates in both the extended ermA genes and the wild-type ermA gene were detected by both Northern blotting and Si nuclease mapping. The 5' ends of the intermediates map to the sequences that encode each of the two ermnA leader peptides, suggesting that the intermediates are produced by stalled erythromycinbound ribosomes acting as barricades to degradation by 5'-to-3' RNases. In addition, whereas erythromycin was found previously to stabilize ermA transcripts only physically, an ernC-cat-86 hybrid transcript was stabilized both physically and functionally by erythromycin.The stability of procaryotic mRNAs varies widely, leading to differential rates of gene expression (for reviews, see references 4 and 7). Several enzymes that can participate in the degradation of mRNAs have been identified, and various sequence determinants and structural features of transcripts have been shown to influence the rates of decay of specific transcripts. Our studies have focused on antibiotic-induced stabilization of transcripts of the erm family of genes from Staphylococcus aureus.The erm family of genes specifies rRNA methylases that confer resistance to macrolide, lincosamide, and streptogramin B antibiotics by reducing the affinity between these antibiotics and ribosomes. Expression of the methylase is induced by nanomolar concentrations of the macrolide antibiotic erythromycin (28). Genetic and biochemical studies of S. aureus gene ermC, a model system for erythromycininduced antibiotic resistance, have demonstrated that synthesis of rRNA methylase is posttranscriptionally controlled by a translational attenuation mechanism (14, 16). According to the translational attenuation model, ermC mRNA is transcribed constitutively, but only low levels of methylase protein are synthesized because the ribosome-binding site and initiation codon for the methylase are sequestered by mRNA secondary structure. In the presence of erythromycin, the antibiotic-bound ribosomes stall while translating a 19-amino-acid leader peptide located near the 5' end of the ermC transcript. The stalled ribosomes effect a conformational change in the secondary structure of the transcript that frees the previously base-paired methylase translation initiation sequences, resulting in an increased rate of methylase synt...

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