Biologic Characteristics of Eight Podoviridae Stx2-converting phage
8株动物源编码Stx2短尾噬菌体的生物学特性

Objective] We studied biologic characteristics of Stx2-converting phage induced from Escherichia coli O157 by mitomycin C. Methods] Eight Stx2-converting phages were isolated from E. coli O157 and identified by PCR. The phage particles were purified and phage DNA was extracted. Random priming digoxin (DIG)-labeled stx2-specific gene probe was prepared for Southern blot. The morphology of these phages were studied by electron microscopy. Protein profiles were analyzed by Sodium Dodecyl Sulphate PolyAcrylamide Gel Electrophoresis (SDS-PAGE). Restriction fragment length polymorphism (RFLP) was used to confirm the size, type, and polymorphism of the purified phage genome. Results] These 8 phages were confirmed Stx2-converting phage and DIG-labeled probe was highly specific. All phages had a regular hexagonal head and a short tail, belonging to Podoviridae phage families. The Stx2 phages had genome sizes in the range of 48 to 65.3kb, consisting of dou-ble-stranded DNA. The restriction fragment length polymorphism of these phages showed different groups, although the SDS-PAGE protein profiles of these phages were similar. Conclusion] These 8 Stx2-converting phages with similar morphol-ogy belonged to Podoviridae phage families. The protein profiles were highly identical. We could differentiate these Stx2-converting phages according to their restriction fragment length polymorphism patterns.