Inhibition of Ampicillin-Resistant Bacteria by Novel Mono-DNAzymes and Di-DNAzyme Targeted to β-Lactamase mRNA

Abstract

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 (Dz₁, Dz₂) and a di-DNAzyme (Dz_1-2) targeted to -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 Dz₁, Dz₂, 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.