Team:USNA Annapolis/Description

Editing the Human Microbiome

Enhancing Our Environment

Our Project

MEW line: Mucosal Early Warning system

In The Beginning...

We followed the classic theme of design, build, test, model and repeat in the field of synthetic biology. Before starting our project, we first sat down and thought about what our focus for this years project would be. Since we were continuing our project from last year, we did some more research on the respiratory microbiome and Sodium Channels.

And for those of you who are unfamiliar with what a microbiome is, a microbiome is community of commensal and symbiotic microorganisms found in all multicellular organisms. These bacteria live among plants and animals and are crucial for immunologic, hormonal and metabolic homeostasis of their host. In order to redesign the construct, we needed to find a less complicated sense and response system than the Arc system, which we used last year.

The Problem

The reason our focus is on the commensal microbiome is because it has the potential to serve as an early warning health indicator for the military. As members of the armed forces we are constantly in tight quarters, which leaves us susceptible to a myriad of bacterial and viral outbreaks. Our objective was to create a commensal microbiome that could serve as an indicator for early warning and detection to track and stop the spread of diseases , which in turn would greatly increase productivity in the armed forces.


Our Instructors suggested that we focus on the Cation-Responsive Protein NhaR of Escherichia coli, due to their role in the activation of pgaA transcription for the production of Biofilms. We decided to look further into the possibility of focusing our project on these two functional parts, pgaA and NhaR, because it directly related to our research in biofilms and the respiratory microbiome. Our goal for the summer was to take NhaR and pgaA’s natural functions and reengineer it to express GFP under the presence of sodium. NhaR is a DNA-binding protein of the LysR family of transcriptional regulators, which activates the transcription of the pgaABCD operon. The pgaA operons natural function is to produce a compound associated with the formation of biofilms. NhaR binds to the promoter region for the pgaA gene naturally regulating transcription of the pgaABCD operon. Using a sodium, we will imitate an ionic response within a biofilm, which will trigger the expression of GFP. This proof of concept experiment will result in two new iGEM parts, the NhaR transcription factor and the pgaA promoter.


The protein within the plasmid backbone of bacteria natural to the human microbiome could be used as a therapeutic drug to protect people from possible toxicants in the environment by sensing their harmful effects within biofilms and host cells or as a therapeutic drug to enhance someone’s natural microbiome by beneficial ionic responses with biofilm formation. For example, it could be taken and used to coat the insides of the respiratory tract to detect changes and prevent unregulated ion channels. This in turn could prevent serious bodily harm with minimal disturbance of ion balance/ biofilms and could enhance microbiome response overall. We consulted one of our resources, LCDR Yasuda, on the possibility of using this type of protein to help in areas of concern for our military members. Other uses include:

  • Protective biofilms throughout your body
  • Bacteria communicate with each other and the host cells
  • Create a sensor for ions for cell to cell communications in a medically relevant way
  • Out on the battlefield and expect to be exposed
  • What’s the response from the respiratory tract
  • Cell-cell communication within biofilms and with the host using ions within the human body