Mattingly 9414716 Bioplastic (biofilm) coatings or biogenic varnishs are natural accretions present on ancient, stable surfaces. These biofilms are from one to 500 micrometers thick and are produced by an apparent symbiotic activity between Lichnothelia fungi and bacteria resembling the Rhodococcus-Actinomycetes group. It requires hundreds of years for this symbiosis to create a continuous coating over a stable surface. Four different types of Lichenothelia- associated varnishs have been identified based on chemical differences and include (1) desert varnish, (2) soil varnish, (3) temple varnish, and (4) tomb varnish. No less than twenty different species of Lichenothelia have been described associated with biofilm formation. However, neither the role of the fungus nor associated bacteria is understood in forming the bioplastic coatings. Therefore, the goal of this NSF-SGER proposal is to: (1) establish the identity of the genus and species of fungi and bacteria involved in biofilm deposition on selected ancient artifacts by using molecular biological techniques, (2) determine the nature of the fungal/bacterial symbiotic association and (3) determine the biochemistry of bioplastic coat formation. %%% Many ancient artifacts are covered by plastic coats, or films. These plastic coatings are very thin and can take thousands of years to form. They are apparently produced biologically by the concerted action of certain types of fungi and bacteria which are able to colonize and grow together on stable, solid surfaces. It is believed that the cellular biofilm-forming center is comprised of a fungus called Lichenothelia and a bacterium, that may be a Rhodococcus or Actinomyces type cell. The goal of the present NSF-SGER proposal is therefore to: (1) find out what types of fungal and/or bacterial cells are involved in biofilm formation, (2) to determine if the different cell types have to live together to form the biofilm, and (3) learn about the chemistry of bio film forming pathway. ***
