Eimaan Bilal, Class of 2028

Many individuals rely on medical implants to improve their quality of life, but such internal devices are prone to bacteria attaching to the implant’s surfaces. This can create a biofilm that produces an exopolysaccharide matrix, increasing one’s risk for certain chronic infections and resistance to antibiotics. It has been hypothesized that biofilm regulation could be achieved by targeting how biofilms disperse so that antibiotics can be more effective. For instance, past research suggests that biofilm formation is regulated by nitric oxide (NO) for various forms of bacteria, and NO signaling pathways and sensors could be implemented for future therapies. Recently, Sajjad Hossain and his colleagues have discovered certain nitric oxide sensing proteins (NosP), a branch of bacterial NO sensors, which have the potential to act as a global regulator that reduces biofilm dispersal. 

To study its effectiveness, Hossain’s team implemented a NosP domain into various bacterial organisms, including V. cholerae, S. oneidensis, P. aeruginosa, and L. pneumophila. They measured the expression levels of histidine kinase, which can lead to hyperbiofilm phenotypes if highly expressed. 

In V. cholerae, the NosP domain inhibits histidine kinase, which suggests that there may be a mechanism present in the molecular structure of the organism that allows NO to act as a detector for biofilm formation. Using both S. oneidensis and P. aeruginosa models, research suggests that proteins involved in NO-mediated biofilm regulation were present, and the NosP from S. oneidensis can regulate kinase activity. Without their NosP NO-dependent pathways, the associated histidine kinase produced biofilms, indicating that NosP domains have the potential to reduce biofilm dispersal. Lastly, in L. pneumophila models, the NO-ligated NosP domain inhibits histidine kinase autokinase activity, which the research group hypothesizes can lead to lower levels of biofilm bacteria in the presence of NO. 

Overall, their studies have indicated that NO-dependent NosP binding proteins must be involved in bacterial biofilm regulation, confirming that lower levels of biofilm can be attained through these signaling pathways. In the future, the group hopes to explore the interactions between H-NOX, another type of bacterial NO sensor protein, and NosP domains in their bacterium models, which possess these domains as well as their respective signaling pathways and networks. While the underlying mechanism for how NO regulation in these bacteria is currently unknown, researchers hope to better understand biofilm regulation as the field of NO signaling expands, paving the way for therapies that reduce biofilm dispersal for patients with medical implants.

Figure 1: Medication and a thermometer.

Works Cited: 

[1] Hossain, S., Nisbett, L.-M., & Boon, E. M. (2017). Discovery of Two Bacterial Nitric Oxide-Responsive Proteins and Their Roles in Bacterial Biofilm Regulation. Accounts of Chemical Research, 50(7), 1633–1639. https://doi.org/10.1021/acs.accounts.7b00095 

[2] Image retrieved from: https://www.pickpik.com/thermometer-headache-pain-pills-medication-tablets-2096