msi postdoctoral fellow 2007

joshua blodgett

Investigating the Roles of Cryptic Biosynthetic Gene
Clusters for Secondary Metabolite Production:

Implications for Bacterial Communication, Competition, and Antibiotic Discovery

 

Joshua Blodgett is a microbiologist studying bacterial interactions mediated by novel small metabolites that may have roles in intercellular communication or antibiosis.

Joshua received his Ph.D in Microbiology from the University of Illinois, Urbana-Champaign IL in 2007 and his B.S in Biological Sciences from the University of Connecticut, Storrs CT in 2001.  He was a teaching fellow in the Microbial Diversity course held at the Marine Biological Laboratory, Woods Hole MA during the summer of 2007. Joshua’s doctoral dissertation focused primarily upon the biosynthetic pathway of phosphinothricin-tripeptide (PTT), a bacterial natural product that is commercially utilized as an herbicide.  His work revealed a number of new enzymes and biosynthetic intermediates that were not previously recognized in reduced-phosphorus antibiotic biosyntheses. 

As a Harvard Microbial Sciences Initiative Fellow, Joshua is working with Jon Clardy and Roberto Kolter to investigate the roles of ‘cryptic’ gene clusters found in the genomes of various bacteria. Many cryptic, or unexpressed, genes are similar to those that encode proteins associated with antibiotic, signaling compound, or siderophore biosyntheses. These types of compounds are interesting from an environmental standpoint because they may mediate communication between diverse groups of microorganisms in their natural microcosms. Because the gene clusters we are interested in do not have known roles or natural products associated with their presence, there are a number of questions we’d like to ask regarding their functions.  These include: Why are the clusters present?  Does their presence correlate with the ability to produce as-of-yet undiscovered bioactive compounds? If so, what activities can we expect from these products? Are specific environmental cues required for their activation?  Lastly, these cryptic clusters have only been discovered following the advent of rapid genome sequencing.  Because we have found them in a number of organisms, perhaps the most important question becomes: Despite decades of dedicated searching, have we grossly underestimated the significance and number of small bioactive metabolites produced by bacteria in general?

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