Environmental DNA transformation resulted in an active phage in Escherichia coli

Abstract

The achievement of an active biological entity from environmental DNA is important in the field of phage. In this study, the environmental DNA extracted from hospital wastewater was transferred into Escherichia coli DH10B and Escherichia coli BL21 with chemical transformation and electroporation. After transformation, overnight cultures were filtered and used as phage source. The efficacies of the techniques were evaluated with spot test and double-layer agar assay. The emerged phage, named as ADUt, was purified and host-range analysis was performed. Phage DNA was isolated, sequenced and restriction profile was determined. The genome was assembled. The phylogenetic tree was constructed via VipTree. The extracted DNA resulted in active phage by the transformation of E. coli DH10B, but not E. coli BL21. The chemical transformation was found more successful than electroporation. ADUt phage was found to be polyvalent and effective against limited strains of Shigella and Escherichia genera. The phage genome size and GC ratio are 166904 bp and 35.67%, respectively. ADUt is a member of Straboviridae family and Tequatrovirus genus. This is the first study that uses environmental DNA for acquiring active phage, which may be an important source of new phage discovery. The result showed that DNA transformation yields active bacteriophage with both chemical transformation and electroporation.