Editor: Craig Shoemaker
ISPsa2, the first mobile genetic element to be described and characterized in the bacterial facultative intracellular pathogen Piscirickettsia salmonis
Article first published online: 12 NOV 2010
© 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved
FEMS Microbiology Letters
Volume 314, Issue 1, pages 18–24, January 2011
How to Cite
Marshall, S. H., Henríquez, V., Gómez, F. A. and Cárdenas, C. (2011), ISPsa2, the first mobile genetic element to be described and characterized in the bacterial facultative intracellular pathogen Piscirickettsia salmonis. FEMS Microbiology Letters, 314: 18–24. doi: 10.1111/j.1574-6968.2010.02132.x
- Issue published online: 3 DEC 2010
- Article first published online: 12 NOV 2010
- Accepted manuscript online: 13 OCT 2010 08:47AM EST
- Received 28 June 2010; revised 22 September 2010; accepted 27 September 2010.Final version published online 12 November 2010.
- Piscirickettsia salmonis;
- insertion sequence;
- inverted repeats;
Piscirickettsia salmonis is a novel, aggressive, facultative Gram-negative bacterium that drastically affects salmon production at different latitudes, with particular impact in southern Chile. Initially, P. salmonis was described as a Rickettsia-like, obligate, intracellular Alphaproteobacteria, but it was reclassified recently as a facultative intracellular Gammaproteobacteria. This designation has prompted the independent growth of the bacterium to a pure state for detailed study of its biology, genetics and epidemiology, properties that are still relatively poorly characterized. The preliminary sequence analysis of a 992-bp fragment of pure P. salmonis DNA allowed us to characterize a novel and complete 863-bp insertion sequence in the bacterial genome (named ISPsa2), which has a novel 16/16 bp perfectly inverted terminal repeat flanking a 726-bp ORF that encodes a putative transposase (Tnp-Psa). The coding sequence of the enzyme shares similarities to that described in some Bacillus species and particularly to those of the IS6 family. ISPsa2 carries its own promoter with standard −10 and −35 sequences, suggesting an interesting potential for plasticity in this pathogenic bacterium. Additionally, the presence of ISPsa2 was confirmed from three isolates of P. salmonis collected from different epizootics in Chile in 2010.