Deciphering the roles of differential type IV pilin expression and N-glycosylation in biofilm formation

PI Name: Pohlschroder, Mechthild<br/><br/>PI Institution: University of Pennsylvania, Philadelphia, PA<br/><br/>Proposal title: Microbial biofilms: Deciphering the roles of differential type IV pilin expression and N-glycosylation<br/><br/>Microbes including bacteria, archaea, algae, and fungi can form communities that are embedded in protective polymeric matrices, called biofilms. These biofilms can be beneficial, for example when making vinegar. But biofilms can also cause great harm as they can be tough and extremely difficult to eradicate, causing for example substantial corrosion and clogging of water and sewage pipes and of the pipelines used to transport oil and gas, as well as crop damage and food spoilage; thus they have significant negative impacts on the economy. This project will address the biological processes that regulate and facilitate the establishment and spread of biofilms and thus will result in a greatly improved understanding of biofilm formation. In particular, we aim to understand the role cell surface structures, termed pilins, and sugar-modifications of proteins play in biofilm formation. We will use cutting edge mass spectrometric (MS) technology to characterize at the molecular level biofilm formation in an archaea model organism, Haloferax volcanii. Our research will not only advance the scientific knowledge in this exciting and timely field of research, but will also provide post-doctoral associates, graduate, undergraduate, and high school students with invaluable training opportunities to study microbiological systems with novel, state-of-the-art technologies. Furthermore, the Pohlschroder lab will take part in science education programs in hopes of stimulating an enthusiasm for science among young students, particularly those who attend the underserved schools of West Philadelphia. The PI will continue to develop microbiology experiments for use by schools having limited resources, and the lab will participate in in-class instruction as well as teacher-training workshops hosted by the University of Pennsylvania.<br/><br/>Recently, sensitive quantitative proteomics analyses have led to the identification of crucial components underpinning processes that are required for biofilm formation in bacteria and archaea. Thus far, however, few attempts to characterize differential protein expression patterns in planktonic cells, as compared to cells from various early stages of biofilm development, have been made. Moreover, given limited technological means, previous mass spectrometric (MS) studies of differential glycosylation during these transitions had not been performed, leaving the role played by this post-translational modification in biofilm formation poorly understood. However, recent technological advances in MS now allow generation of the most complete prokaryotic glycoproteome available, in both planktonic cells and biofilms, clarifying the mechanisms involved at various stages of biofilm formation. Using genetic and biochemical approaches in concert with quantitative glycoproteomics, the lab will focus on determining how differential expression and post-translational modifications of type IV pilins, which are subunits of the evolutionarily conserved cell surface structures, type IV pili, affect biofilm formation. These methods will likely also lead to the identification and characterization of other proteins that play roles in biofilm development. Because archaea and bacteria share many features in common, these studies will not only promote a better understanding of the mechanisms underlying archaeal biofilm formation but will also provide insights for those studying bacterial biofilms.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.