Kelsey Barrasso, Samit Watve, Chelsea A. Simpson Affiliation: Department of Biology, Indiana University, Bloomington, Indiana, United States of America Logan J. Geyman Affiliation: Department of Biology, Indiana University, Bloomington, Indiana, United States of America ORCID logo https://orcid.org/0000-0001-6697-6725 Julia C. van Kessel * E-mail: jcvk@indiana.edu (JCVK); wai-leung.ng@tufts.edu (WLN) Affiliation: Department of Biology, Indiana University, Bloomington, Indiana, United States of America Wai-Leung Ng * E-mail: jcvk@indiana.edu (JCVK); wai-leung.ng@tufts.edu (WLN) Affiliations Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America, Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America ORCID logo https://orcid.org/0000-0002-8966-6604 Introduction Quorum-sensing (QS) systems, which rely on the production and detection of chemical signals called autoinducers (AIs) made by the bacteria themselves, are classically thought to be employed as a means to sense “self,” ensuring that bacteria cooperate and share resources to benefit their kin. ...most QS receptors are found to be specific for their cognate AIs. Vibrio QS systems that detect host-generated signals Many Vibrio species including Vibrio cholerae, Vibrio harveyi, and Vibrio fischeri spend part of their life cycle inside animal hosts either as a pathogen or as a symbiont. Phosphorylated LuxO promotes and inhibits the production of master transcriptional regulators AphA and HapR, respectively, resulting in the activation of virulence and biofilm gene expression at LCD, which is critical for V. cholerae host colonization 18. The VqmA/DPO pathway inhibits biofilm formation in V.c. AI-2, autoinducer-2; CAI-1, cholera autoinducer-1; CP, cytoplasm; DPO, 3,5-dimethyl-pyrazin-2-ol; HAI-1, harveyi autoinducer-1; HK, histidine kinase; H-NOX, heme nitric oxide/oxygen binding; NO, nitric oxide; PP, periplasm; QS, quorum sensing.