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Search This Site | People | Departments | Penn State
William Bentley
Department of Bioengineering
University of Maryland
Tuesday, February 5, 2008
102 Chemistry Building
10:00 a.m. - 11:00 a.m.
Abstract
The biological signal transduction process is the means by which external signals are incorporated into information that directly or indirectly alters gene expression and ultimately, phenotype.
The hierarchical structure of signal transduction processes is a topic of intense research.
Microbial quorum sensing is responsible for a variety of phenotypes and is rich in diversity and modes of action.
As such, quorum sensing represents a "guide" for learning how signals can be translated into altered phenotype.
As microbial communities occupy a confined space over time, concentrations of extracellular signaling molecules accumulate, providing stimulus for unique and varied cellular responses as well as protection from competing microbial communities. This is an application area ripe for chemical engineering science. Referred to as "quorum sensing" for its often reported and coincident dependence on high population density, extracellular signaling provides a new basis for control over molecular and cellular processes as well as population behavior, perhaps in a manner more consistent with that of native machinery. Our laboratory has uncovered many of the molecular features of the QS autoinducer-2 system, which in turn is thought of as a "universal" communication system connecting many bacterial species. In particular, QS regulated transcriptional regulator, LsrR, is shown to affect many metabolic, motility, aggregation, and survival processes. The exact mode by which LsrR works is unclear, but a natural switching mechanism based on the phosphorylation state of a signal molecule AI-2 provides the regulatory basis for a specific gene's regulation.
This presentation will describe the features of this system that make it particularly amenable to modification and abstraction for recognizing various signals and for modulating biochemical pathways. We have constructed bioMEMS systems for elucidating pathway behavior and understanding signal transduction. We have also created a novel protein expression system based on autoinduction. These and other issues and applications will be described.