Scientific Graphics
Gibbs Lab Overview
The Gibbs lab investigates the molecular mechanisms underlying bacterial social behaviors. They focus on interbacterial communication systems in the opportunistic gut pathogen, Proteus mirabilis. How these cells respond to this communication can affect individual cell fitness and community structure.
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For more information, visit the Gibbs lab website.
Bacterial Competition and Protection Mechanisms
These figures are from a review on how bacteria compete with one another in dense environments like the human gut microbiome.
Interbacterial Competition Systems
Three ways bacteria inject toxic proteins (effectors) into neighboring cells are the type VI secretion system (T6SS), contact-independent bacteriocins, and contact-dependent inhibition (CDI). Effectors have a variety of ways to inhibit neighboring cells, such as by attacking essential biomolecules like DNA and RNA or by attacking the cell wall. Sibling bacteria have a corresponding immunity protein that neutralizes the effector's activity.
Neutralization Mechanisms of Bacterial Antitoxins and Immunity Proteins
Pairs of toxic and neutralizing proteins are found throughout bacterial genomes. Some of these proteins are involved in persistence or viral defense (e.g., "toxin/antitoxin" or TA pairs), while others are involved in interbacterial competition (e.g., "effector/immunity" or EI pairs). TA pairs are usually grouped by their method of neutralization, whereas EI pairs are grouped by their secretion method (see above). EI pairs have long been thought to only inhibit through active site binding. However, recent data suggests they may utilize broader neutralization mechanisms that are also shared by TA pairs.