Oxygen (O2) is an essential environmental cue that affects the physiology, respiration, and virulence of bacteria. Globin-coupled sensor (GCS) proteins play an important role in O? response through direct ligand binding to the heme prosthetic group in the sensory globin domain. GCS proteins control a variety of physiological processes such as motility, biofilm, and virulence factor production. These functions are generally controlled through intracellular signaling pathways using small nucleotide second messengers. The use of small nucleotide signaling allows for timely response to varying oxygen levels and environmental conditions. One such molecule, cyclic di-GMP (c-di-GMP), is a major regulatory molecule of bacterial processes. C-di-GMP is synthesized by diguanylate cyclase (DGC) and broken down by phosphodiesterase (PDE) domain-containing enzymes. Generally, elevated c-di-GMP levels enhance biofilm formation, while lower c-di-GMP concentrations enhance motility, enabling bacteria to search for more favorable environments. By incorporating oxygen availability into c-di-GMP signaling, DGC-containing GCS proteins enable bacteria to regulate their behavior based on a specific environmental signals. The Escherichia coli DosCP system is a unique example of an oxygen sensing DGC-PDE complex. DosCP enables dynamic regulation of intracellular c-di-GMP levels by integrating environmental oxygen sensing through its heme-based sensory domain, with DosC being a GCS protein, and DosP containing a sensory Pern-ARNT-Sim (PAS) domain. The DosCP system features a direct interplay between c-di-GMP synthesis and degradation, allowing for precise and rapid modulation of bacterial responses. The DosCP system serves as a unique model to study the structural and functional relationships between oxygen-dependent c-di-GMP metabolic proteins. This work done integrates fluorescence-based high-throughput monitoring to investigate DosCP-dependent growth phenotypes. Fluorescently tagged WT and ?dosCP E. coli expressing YFP, CFP, mEGFP, mCardinal, mCitrine, mGreenlantern, or mBFP were used to track bacterial growth and competition in real-time using a fluorescence microplate reader. This method allows the observation of these E. coli strains under different media conditions, assessing the role of DosCP on medium-dependent bacterial growth. Optimization of induction and detection conditions to allow for accurate measurements of growth through fluorescence output were performed, which can then be used as a proxy to measure bacterial competition.