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 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 Reunanen, J.
Right arrow Articles by Saris, P. E. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Reunanen, J.
Right arrow Articles by Saris, P. E. J.
Agricola
Right arrow Articles by Reunanen, J.
Right arrow Articles by Saris, P. E. J.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, July 2003, p. 4214-4218, Vol. 69, No. 7
0099-2240/03/$08.00+0     DOI: 10.1128/AEM.69.7.4214-4218.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

Microplate Bioassay for Nisin in Foods, Based on Nisin-Induced Green Fluorescent Protein Fluorescence

J. Reunanen and P. E. J. Saris*

Applied Chemistry and Microbiology, University of Helsinki, Helsinki, Finland

Received 22 October 2002/ Accepted 7 April 2003

A plasmid coding for the nisin two-component regulatory proteins, NisK and NisR, was constructed; in this plasmid a gfp gene (encoding the green fluorescent protein) was placed under control of the nisin-inducible nisF promoter. The plasmid was transformed into non-nisin-producing Lactococcus lactis strain MG1614. The new strain could sense extracellular nisin and transduce it to green fluorescent protein fluorescence. The amount of fluorescence was dependent on the nisin concentration, and it could be measured easily. By using this strain, an assay for quantification of nisin was developed. With this method it was possible to measure as little as 2.5 ng of pure nisin per ml in culture supernatant, 45 ng of nisin per ml in milk, 0.9 µg of nisin in cheese, and 1 µg of nisin per ml in salad dressings.

* Corresponding author. Mailing address: Applied Chemistry and Microbiology, P.O. Box 56, FIN-00014 University of Helsinki, Finland. Phone: 358 9 19159369. Fax: 358 9 19159322. E-mail: per.saris{at}helsinski.fi.

Applied and Environmental Microbiology, July 2003, p. 4214-4218, Vol. 69, No. 7
0099-2240/03/$08.00+0     DOI: 10.1128/AEM.69.7.4214-4218.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Hilmi, H. T. A., Kyla-Nikkila, K., Ra, R., Saris, P. E. J. (2006). Nisin induction without nisin secretion.. Microbiology 152: 1489-1496 [Abstract] [Full Text]  
  • Hakovirta, J., Reunanen, J., Saris, P. E. J. (2006). Bioassay for Nisin in Milk, Processed Cheese, Salad Dressings, Canned Tomatoes, and Liquid Egg Products. Appl. Environ. Microbiol. 72: 1001-1005 [Abstract] [Full Text]  
  • Beasley, S. S., Saris, P. E. J. (2004). Nisin-Producing Lactococcus lactis Strains Isolated from Human Milk. Appl. Environ. Microbiol. 70: 5051-5053 [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»