Lantibiotics as natural food preservative and bacterial disease prevention

The lantibiotics are becoming interesting as natural preservatives to prevent harmful bacteria in foods. [1]

They are easy to digest, nontoxic, do not induce allergies and are difficult for dangerous bacteria to develop resistance against. Lantibiotics are a class of antimicrobial peptides that are characterised by the presence of lanthionine and/or methyllanthionine residues. Lantibiotics are produced by Gram-positive bacteria such as Streptococcus and Streptomyces  Bacillus, Bifidobacterium and others. They are strong antimicrobials  and may be usefull in food preservation.

Classification of lantibiotics [2]
Type A lantibiotics:  are long flexible molecules - e.g. nisin, subtilin, epidermin. Subgroup AI includes mutacin II, subgroup AII includes mutacin I & III. Type A lantibiotics act by pore formation,
Type B lantibiotics:  are globular - e.g. mersacidin, actagardine, cinnamycin. type B lantibiotics inhibit peptidoglycan biosynthesis.
Nisin and epidermin are members of a family of lantibiotics that bind to a cell wall precursor lipid component of target bacteria and disrupt cell wall production. The duramycin family of lantibiotics binds phosphoethanolamine in the membranes of its target cells and seem to disrupt several physiological functions.

List of known lantibiotics [3]
A description of all known lantibiotics and the producer organism is given in Bactibase database.

Lantibiotic production in broth media [4]
Lee, Li and O'Sullivan 2011 report the production of lantibiotic from Bifidobacterium longum DJO10A in agar culture but  suppression of its expression in broth media. The authors found that the adding an agar culture extract to a broth cultures of B. longum DJO10A induces lanA gene expression of lantibiotic in liquid media. The transcription start analysis of lanA revealed a 284 bp 5' untranslated region to be involved in repression of transcription in broth culture. An  inverted repeat structure located at -75 bp relative to the transcription start functions as a binding site for the two component response regulator. Better understanding of the regulation of  lanA gene is important for the production of this lantibiotic in broth cultures.

[1] Cotter1 PD, Hill C,  Ross RP: Bacterial Lantibiotics: Strategies to Improve Therapeutic Potential. Current Protein and Peptide Science, 2005, 6, 61-75
http://www.benthamscience.com/cpps/sample/cpps6-1/0007K.pdf

[2] Lantibiotics. Wikipedia
http://en.wikipedia.org/wiki/Lantibiotic

[3] Bactibase Database dedicated to bacteriocins
http://bactibase.pfba-lab-tun.org/bacteriocinslist.php?x_Class=lantibiotic

[4] Lee J-H, Li X, O'Sullivan DJ: Transcription Analysis Of A Lantibiotic Gene Cluster From Bifidobacterium longum DJO10A. Appl. Environ. Microbiol. doi:10.1128/AEM.00571-11
http://aem.asm.org/cgi/content/abstract/AEM.00571-11v1