Antimicrobial peptides are produced by all organisms in response to microbial invasion and are considered as promising candidates for future antibiotics. There is a wealth of evidence that many of them interact and increase the permeability of bacterial membranes as part of their killing mechanism. However, it is not clear whether this is the lethal step. To address this issue, we studied the interaction of the antimicrobial peptide temporin L with Escherichia coli by using fluorescence, confocal and electron microscopy. The peptide previously isolated from skin secretions of the frog Rana temporaria has the sequence FVQWFSKFLGRIL-NH2. With regard to fluorescence microscopy, we applied, for the first time, a triple-staining method based on the fluorochromes 5-cyano-2,3-ditolyl tetrazolium chloride, 4´,6-diamidino-2-phenylindole and FITC. This technique enabled us to identify, in the same sample, both living and total cells, as well as bacteria with altered membrane permeability. These results reveal that temporin L increases the permeability of the bacterial inner membrane in a dose-dependent manner without destroying the cell's integrity. At low peptide concentrations, the inner membrane becomes permeable to small molecules but does not allow the killing of bacteria. However, at high peptide concentrations, larger molecules, but not DNA, leak out, which results in cell death. Very interestingly, in contrast with many antimicrobial peptides, temporin L does not lyse E. coli cells but rather forms ghost-like bacteria, as observed by scanning and transmission electron microscopy. Besides shedding light on the mode of action of temporin L and possibly that of other antimicrobial peptides, the present study demonstrates the advantage of using the triple-fluorescence approach combined with microscopical techniques to explore the mechanism of membrane-active peptides in general.
Skip Nav Destination
Follow us on Twitter @Biochem_Journal
Article navigation
Research Article|
June 15 2004
Effects of the antimicrobial peptide temporin L on cell morphology, membrane permeability and viability of Escherichia coli
Maria Luisa MANGONI;
Maria Luisa MANGONI
1
*Dipartimento di Scienze Biochimiche ‘A. Rossi Fanelli’, Istituto Pasteur-Fondazione Cenci Bolognetti, Azienda Ospedale S. Andrea, and CNR Istituto di Biologia e Patologia Molecolari, Università ‘La Sapienza’, I-00185 Roma, Italy
1To whom correspondence should be addressed (email [email protected]).
Search for other works by this author on:
Niv PAPO;
Niv PAPO
†Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
Search for other works by this author on:
Donatella BARRA;
Donatella BARRA
*Dipartimento di Scienze Biochimiche ‘A. Rossi Fanelli’, Istituto Pasteur-Fondazione Cenci Bolognetti, Azienda Ospedale S. Andrea, and CNR Istituto di Biologia e Patologia Molecolari, Università ‘La Sapienza’, I-00185 Roma, Italy
Search for other works by this author on:
Maurizio SIMMACO;
Maurizio SIMMACO
*Dipartimento di Scienze Biochimiche ‘A. Rossi Fanelli’, Istituto Pasteur-Fondazione Cenci Bolognetti, Azienda Ospedale S. Andrea, and CNR Istituto di Biologia e Patologia Molecolari, Università ‘La Sapienza’, I-00185 Roma, Italy
Search for other works by this author on:
Argante BOZZI;
Argante BOZZI
‡Dipartimento di Scienze e Tecnologie Biomediche, Università dell'Aquila, Via Vetoio, I-67100 L'Aquila, Italy
Search for other works by this author on:
Antonio DI GIULIO;
Antonio DI GIULIO
‡Dipartimento di Scienze e Tecnologie Biomediche, Università dell'Aquila, Via Vetoio, I-67100 L'Aquila, Italy
Search for other works by this author on:
Andrea C. RINALDI
Andrea C. RINALDI
§Dipartimento di Scienze e Tecnologie Biomediche, Sezione di Chimica Biologica e Biotecnologie Biochimiche, Università di Cagliari, I-09042 Monserrato, Italy
Search for other works by this author on:
Publisher: Portland Press Ltd
Received:
December 23 2003
Revision Received:
March 01 2004
Accepted:
March 19 2004
Accepted Manuscript online:
March 19 2004
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London ©2004
2004
Biochem J (2004) 380 (3): 859–865.
Article history
Received:
December 23 2003
Revision Received:
March 01 2004
Accepted:
March 19 2004
Accepted Manuscript online:
March 19 2004
Citation
Maria Luisa MANGONI, Niv PAPO, Donatella BARRA, Maurizio SIMMACO, Argante BOZZI, Antonio DI GIULIO, Andrea C. RINALDI; Effects of the antimicrobial peptide temporin L on cell morphology, membrane permeability and viability of Escherichia coli. Biochem J 15 June 2004; 380 (3): 859–865. doi: https://doi.org/10.1042/bj20031975
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
Biochemical Society Member Sign in
Sign InSign in via your Institution
Sign in via your InstitutionGet Access To This Article
Follow us on Twitter @Biochem_Journal
Open Access for all
We offer compliant routes for all authors from 2025. With library support, there will be no author nor reader charges in 5 journals. Check here |
![]() View past webinars > |