AEM
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
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 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 Khandelwal, P.
Right arrow Articles by Banerjee-Bhatnagar, N.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Khandelwal, P.
Right arrow Articles by Banerjee-Bhatnagar, N.
Agricola
Right arrow Articles by Khandelwal, P.
Right arrow Articles by Banerjee-Bhatnagar, N.
Applied and Environmental Microbiology, April 2003, p. 2032-2037, Vol. 69, No. 4
0099-2240/03/$08.00+0     DOI: 10.1128/AEM.69.4.2032-2037.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

Insecticidal Activity Associated with the Outer Membrane Vesicles of Xenorhabdus nematophilus

Puneet Khandelwal1 and Nirupama Banerjee-Bhatnagar2*

Centre For Biotechnology, Jawaharlal Nehru University,1 International Center For Genetic Engineering and Biotechnology, New Delhi, India2

Received 16 October 2002/ Accepted 9 January 2003

Xenorhabdus nematophilus secretes a large number of proteins into the culture supernatant as soluble proteins and also as large molecular complexes associated with the outer membrane. Transmission electron micrographs of X. nematophilus cells showed that there was blebbing of the outer membrane from the surface of the bacterium. The naturally secreted outer membrane vesicles (OMVs) were purified from the culture supernatant of X. nematophilus and analyzed. Electron microscopy revealed a vesicular organization of the large molecular complexes, whose diameters varied from 20 to 100 nm. A sodium dodecyl sulfate-polyacrylamide gel electrophoresis profile of the vesicles showed that in addition to outer membrane proteins, several other polypeptides were also present. The membrane vesicles contained lipopolysaccharide, which appeared to be of the smooth type. Live cells of X. nematophilus and the OMV proteins derived from them exhibited oral insecticidal activity against neonatal larvae of Helicoverpa armigera. The proteins present in the OMVs are apparently responsible for the biological activity of the OMVs. The soluble proteins left after removal of the OMVs and the outer membrane proteins also showed low levels of oral toxicity to H. armigera neonatal larvae. The OMV protein preparations were cytotoxic to Sf-21 cells in an in vitro assay. The OMV proteins showed chitinase activity. This is the first report showing toxicity of outer membrane blebs secreted by the insect pathogen X. nematophilus into the extracellular medium.


* Corresponding author. Mailing address: International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India. Phone: 91-11-6181242. Fax: 91-11-6162316. E-mail: nirupama{at}icgeb.res.in.


Applied and Environmental Microbiology, April 2003, p. 2032-2037, Vol. 69, No. 4
0099-2240/03/$08.00+0     DOI: 10.1128/AEM.69.4.2032-2037.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.




This article has been cited by other articles:




Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. Microbiol. Mol. Biol. Rev. Eukaryot. Cell All ASM Journals

Copyright © 2003 by the American Society for Microbiology. All rights reserved.