1. 5/15/08Caltech iGEM Meeting #6 Presentation by Robert Ovadia Mouthwash A Closer Look at Biofilms Picture taken from: http://www.ehponline.org/docs/1998 /106-12/innova-biofilmB.JPG

2. 5/15/08Caltech iGEM Meeting #6 Presentation by Robert Ovadia Introduction 2 Target the biofilm, before it develops. As mentioned last week, biofilms on our teeth are formed between the interaction with S. mutans. If we prevent this interaction, we can prevent biofilm formation. Without a biofilm, bacterial species in our mouth are vulnerable and can hopefully be destroyed with simpler methods. What we want? Introduction What we want? Mechanism of action of S. mutans Methods Ways to block adhesion Discussion

3. 5/15/08Caltech iGEM Meeting #6 Presentation by Robert Ovadia Introduction What we want? Mechanism of action of S. mutans Methods Ways to block adhesion Discussion 3 Mechanism of action of S. mutans pac Step 1: Expression of the cell surface adhesion antigen PAc Step 2:

4. 5/15/08Caltech iGEM Meeting #6 Presentation by Robert Ovadia Methods 4 Ways to block adhesion Design a strain of S. lactis with the pac gene. Binding of both S. lactis and S. mutans would force competitive binding. If possible, we can have our strain grow at a wanted rate that would enable it to block off S. mutans. Introduction What we want? Mechanism of action of S. mutans Methods Ways to block adhesion Discussion

5. 5/15/08Caltech iGEM Meeting #6 Presentation by Robert Ovadia Methods 5 Ways to Block Adhesion Use antibodies 1 Problem: How can we connect this to synthetic biology? To my knowledge, I haven’t seen Ab’s in the registry, so if we could make it work, adding new parts is always a plus. Design our Ab’s to bind to the PAc antigen and destroy S. mutans with WBC. Introduction What we want? Mechanism of action of S. mutans Methods Ways to block adhesion Discussion

6. 5/15/08Caltech iGEM Meeting #6 Presentation by Robert Ovadia Methods 6 Ways to Block Adhesion Binding of S. mutans Binding of Ab Binding of Ab, with neutrophil ready to destry Introduction What we want? Mechanism of action of S. mutans Methods Ways to block adhesion Discussion

7. 5/15/08Caltech iGEM Meeting #6 Presentation by Robert Ovadia Discussion 7 Now that we hopefully prevented biofilm formation, we must look on how long this will last? Still need to have our strain smell good, taste good, out compete S. mutans, and only have to use once a week or less. Possibily use one strain of S. lactis for biofilm prevention, and use E. coli for smell, taste, etc. Would it be ideal to use 2 strains in our mouthwash or toothpaste? What Next? Introduction What we want? Mechanism of action of S. mutans Methods Ways to block adhesion Discussion

8. 5/15/08Caltech iGEM Meeting #6 Presentation by Robert Ovadia References Iwaki M, Okahashi N, Takahashi I, Kanamoto T, Sugita-Konishi Y, Aibara K, and Koga T. Oral immunization with recombinant Streptococcus lactis carrying the Streptococcus mutans surface protein antigen gene. Infect Immun 1990 Sep; 58(9) 2929-34. pmid:2117575. Kruger C, Hu Y, Pan Q, Marcotte H, Hultberg A, Delwar D, van Dalen PJ, Pouwels PH, Leer RJ, Kelly CG, van Dollenweerd C, Ma JK, and Hammarstrum L. In situ delivery of passive immunity by lactobacilli producing single-chain antibodies. Nat Biotechnol 2002 Jul; 20(7) 702- 6. doi:10.1038/nbt0702-702 pmid:12089555