This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Singh, J.
Right arrow Articles by Banerjee, N.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Singh, J.
Right arrow Articles by Banerjee, N.

 Previous Article  |  Next Article 

Journal of Bacteriology, June 2008, p. 3877-3885, Vol. 190, No. 11
0021-9193/08/$08.00+0     doi:10.1128/JB.00209-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Transcriptional Analysis and Functional Characterization of a Gene Pair Encoding Iron-Regulated Xenocin and Immunity Proteins of Xenorhabdus nematophila{triangledown} ,{dagger}

Jitendra Singh1,2 and Nirupama Banerjee2*

School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India,1 International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India2

Received 11 February 2008/ Accepted 16 March 2008

We describe a two-gene cluster encoding a bacteriocin, xenocin, and the cognate immunity protein in the insect-pathogenic bacterium Xenorhabdus nematophila, which infects and kills larval stages of the common crop pest Helicoverpa armigera. The two genes, xcinA and ximB, are present in the genome as a single transcriptional unit, which is regulated under SOS conditions. The stress-inducible promoter was activated by mitomycin C, glucose, and Fe3+ depletion and at an elevated temperature when it was tested in Escherichia coli cells. Expression of the xenocin protein alone in E. coli inhibited the growth of this organism. The growth inhibition was abolished when the immunity protein was also present. A recombinant xenocin-immunity protein complex inhibited the growth of E. coli indicator cells when it was added exogenously to a growing culture. Xenocin is an endoribonuclease with an enzymatically active C-terminal domain. Six resident bacterial species (i.e., Bacillus, Enterobacter, Enterococcus, Citrobacter, Serratia, and Stenotrophomonas species) from the H. armigera gut exhibited sensitivity to recombinant xenocin when the organisms were grown under iron-depleted conditions and at a high temperature. Xenocin also inhibited the growth of two Xenorhabdus isolates. This study demonstrates that Fe3+ depletion acts as a common cue for synthesis of xenocin by X. nematophila and sensitization of the target strains to the bacteriocin.

* Corresponding author. Mailing address: International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India. Phone: 91-11-26181242. Fax: 91-11-26162316. E-mail: nirupama{at}icgeb.res.in

{triangledown} Published ahead of print on 28 March 2008.

{dagger} Supplemental material for this article may be found at http://jb.asm.org/.

Journal of Bacteriology, June 2008, p. 3877-3885, Vol. 190, No. 11
0021-9193/08/$08.00+0     doi:10.1128/JB.00209-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • van der Hoeven, R., Forst, S. (2009). OpnS, an Outer Membrane Porin of Xenorhabdus nematophila, Confers a Competitive Advantage for Growth in the Insect Host. J. Bacteriol. 191: 5471-5479 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»