Proposal Title

Modeling Sporulation Through the Environmentally Regulated Genetic Network in B. subtilis

Primary Faculty Mentor’s Name

Yi Jiang

Session Format

Oral (max. 15 minutes)

Abstract

Biofilms are colonies of microbial organisms held together by a polymeric extracellular matrix on surfaces. Biofilms are prevalent in natural, industrial, and health settings. Much of the molecular mechanisms for biofilm formation is still unclear, in particular how cells switch their phenotypic behavior within a biofilm. To gain an understanding of phenotypic switching in biofilms, we focus on sporulation in the Bacillus subtilis (B. subtilis) species. Empirical evidence shows that Spo0A is the master protein determining cell phenotype: High concentrations of phosphorylated-Spo0A (Spo0A~P) trigger sporulation while low levels lead to matrix production. We constructed a genetic network that integrates both nutrient-regulated and quorum-sensing pathways in B. subtilis. Our model employs a system of coupled ordinary differential equations to study the genetic network in response to nutrient availability and surrounding cell density. Dynamical systems analysis of these equations reveal that both starvation and overcrowding as measured by the level of autoinducer can raise Spo0A~P levels and trigger sporulation. This simple model of the B. subtilis genetic network is the first step in understanding the growth mechanisms of biofilms under varying environmental conditions.

Keywords

biofilms, Bacillus subtillis, genetic network, sporulation

Presentation Year

2017

Publication Type and Release Option

Event

 

Modeling Sporulation Through the Environmentally Regulated Genetic Network in B. subtilis

Biofilms are colonies of microbial organisms held together by a polymeric extracellular matrix on surfaces. Biofilms are prevalent in natural, industrial, and health settings. Much of the molecular mechanisms for biofilm formation is still unclear, in particular how cells switch their phenotypic behavior within a biofilm. To gain an understanding of phenotypic switching in biofilms, we focus on sporulation in the Bacillus subtilis (B. subtilis) species. Empirical evidence shows that Spo0A is the master protein determining cell phenotype: High concentrations of phosphorylated-Spo0A (Spo0A~P) trigger sporulation while low levels lead to matrix production. We constructed a genetic network that integrates both nutrient-regulated and quorum-sensing pathways in B. subtilis. Our model employs a system of coupled ordinary differential equations to study the genetic network in response to nutrient availability and surrounding cell density. Dynamical systems analysis of these equations reveal that both starvation and overcrowding as measured by the level of autoinducer can raise Spo0A~P levels and trigger sporulation. This simple model of the B. subtilis genetic network is the first step in understanding the growth mechanisms of biofilms under varying environmental conditions.