Characterization of E-type colicinogenic plasmids from Shigella sonnei.
FEMS Microbiol Lett
; 364(7)2017 04 01.
Article
en En
| MEDLINE
| ID: mdl-28333314
Colicinogenic plasmids encode toxic proteins which have antagonistic activity against closely related bacteria. This study describes the molecular characterization of three colicinogenic plasmids designated as pSSE3, pSSE and pSSE2, each with a molecular size of â¼6 kb, identified in clinical isolates of Shigella sonnei. Sequence analysis revealed that pSSE and pSSE2 shared extensive sequence homology with each other and with Escherichia coli E-type colicinogenic plasmids. The plasmid pSSE3 lacked an additional gene imparting immunity to colicin E8, a unique feature not observed in any of the previously reported sequences of colicin E3 plasmids. Incomplete digestion of colicinogenic plasmids by restriction endonucleases, metachromatic staining with acridine orange and presence of single stranded initiation (ssi) region confirmed the coexistence of ssDNA along with dsDNA. Plasmid copy number as determined by real-time PCR was found to be about 20. Transmission electron microscopy revealed DNA impairment in test bacteria after colicin exposure. We hypothesize that S. sonnei has acquired E-group colicin plasmids from its close relative E. coli, with their sequences undergoing subtle changes depending on the cohabitation in the same milieu.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Plásmidos
/
Shigella sonnei
/
Colicinas
Idioma:
En
Revista:
FEMS Microbiol Lett
Año:
2017
Tipo del documento:
Article
País de afiliación:
India
Pais de publicación:
Reino Unido