The role of the Vibrio cholerae Type VI secretion system during kin cell interaction, biofilm formation and priority effects

Author

Karen A. Castro, CUNY City CollegeFollow

Date of Award

2024

Document Type

Thesis

Department

Biology

First Advisor

Stefan U. Pukatzki

Keywords

Vibrio cholerae, A1552, Type VI secretion system (T6SS), biofilms, cluster segregation, kin-sensisitive

Abstract

Vibrio cholerae’s Type VI secretion system (T6SS) is one of the arsenals used by the bacteria for its long-term survival in different environments, against a variety of opponents, and for its maintained pathogenicity in vulnerable regions of the world. Therefore, the more we understand about the activity of the T6SS, the closer we get to understanding its role in bacterial competition; inter-and-intra, and how this shapes a bacterial niche. Further, although the probiotic-like effect in the V. cholerae vaccine is described to work fast due to niche uptake hindering colonization of toxigenic strains, it is not yet clear if there is a direct connection between priority effects and T6SS activity in kin cell interaction, and how this interaction shapes a bacterial niche. Therefore, to mimic the internal spatial restriction in a host we formed biofilms in-vitro, using A1552 kin V. cholerae cells, priority effects as a temporal aspect, and confocal laser microscopy to observe the relation between T6SS and priority effects, and their effect on spatial formation of biofilms during kin-cell interaction. We found that in-vitro, when considering priority effects and in a kin-cell interaction, the first colonizing strain will be given and maintain a fitness advantage over the challenger strain. Additionally, microscopy images suggested the first colonizing strain to have an advantage in the spatial structure of the biofilm, forming and expanding its clusters at a greater scale than the challenger strain, only when the first colonizing strain lacked of its T6SS immunity genes and firing ability (∆tsiV1, ∆tsiV2, ∆tsiV3I, ∆vasK), and thus became kin-sensitive. Results indicate that during a kin-cell interaction, T6SS compatibility in addition to priority effects dictate the fitness of the first colonizing strain, and the spatial structure of the biofilm. When the first colonizing strain is non-kin-sensitive, it maintains its fitness advantage given by priority effects, and when the first colonizing strain is kin-sensitive to the challenger strain, its fitness is hindered.

Recommended Citation

Castro, Karen A., "The role of the Vibrio cholerae Type VI secretion system during kin cell interaction, biofilm formation and priority effects" (2024). CUNY Academic Works.
https://academicworks.cuny.edu/cc_etds_theses/1188