Inhibition of ampicillin-resistant bacteria by novel mono-DNAzymes and di-DNAzyme targeted to β-lactamase mRNA

In view of the weakness of antibiotics and the properties of antisense drugs, we applied DNAzymes to the field of drug resistance in bacteria. Two 10-23 mono-DNAzymes (Dz(1), Dz(2)) and a di-DNAzyme (Dz(1-2)) targeted to beta-lactamase mRNA were designed to determine to what degree the growth of ampicillin-resistant bacteria (TEM-1, TEM-3) was inhibited. All three DNAzymes can play a role both in vitro and in vivo. In vitro, they exhibited high catalytic efficiency (k(cat)/K-M) of 63.5, 91.1, and 30.8 pM(-1) (.) min(-1), respectively, under multiple-turnover conditions. In vivo, after 9 hours' incubation, the degree of inhibition of Dz(1), Dz(2), and Dz(1-2) for TEM-1 bacteria was 27.2%, 39.6%, and 57.7%, respectively, and that for TEM-3 bacteria was 39.1%, 44%, and 62.6%, respectively. Dz(1-2) showed the greatest inhibiting effect, demonstrating in vivo activity may be increased by constructing multiple-target DNAzymes. The results indicated a potential possibility for DNAzymes to act as a new type of antibacterial or a tool of gene functional analysis for prokaryocytes.