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Mechanisms of cell contact-dependent prey killing by Myxococcus xanthus

08.02.2024 12:30 pm 2:00 pm Joint Microbiological Colloquium Christine Kaimer

Speaker: Christine Kaimer, (Ruhr University Bochum)

Host: Samuel Wagner

Date & Time: 08.02.2024 | 12:30 – 2 p.m.

Venue:  Lecture hall 3M07, GUZ

Public event. No registration needed.


Predatory bacteria are found in various habitats and have adapted different mechanisms to kill and consume other microorganisms. We investigate the predation mechanisms of Myxococcus xanthus, a soil bacterium, which preys on a broad range of bacteria and fungi, and employs a multilayered predation strategy (1).

Secreted bacteriolytic proteins can lyse Gram positive prey at a distance, but predation of Gram negative bacteria requires direct cell-cell contact with M. xanthus (2). Recently, we identified two atypical protein secretion systems that fulfill distinct functions during contact-dependent prey cell killing (3): a Tad-like system (Kil) is necessary to induce prey cell death upon cell contact with M. xanthus, while a needle-less Type III-like secretion system (T3SS*) is required for prey cell lysis. Fluorescence microscopy revealed that components of both secretion systems accumulate at the predator-prey contact site prior to killing. Also, both secretion systems are required to extract sufficient nutrients from prey bacteria to power M. xanthus cell motility and swarm expansion. Hence, our observationshint at a functional interaction of two atypical protein secretion systems in bacterial killing.
Our current research focuses on the secretion mechanism of the needle-less T3SS* and its interplay with the Tad-like Kil system.

(1) Kaimer C, Weltzer ML, Wall D (2023). Two reasons to kill: predation and kin

discrimination in myxobacteria. Microbiology (Reading) 169: 001372.

(2) Arend KI et al. (2021) Myxococcus xanthus predation of Gram-positive or Gram-negative

bacteria is mediated by different bacteriolytic mechanisms. Appl Environ Microbiol. 87:


(3) Thiery S et al. (2022) The predatory soil bacterium Myxococcus xanthus combines a

Tad- and an atypical type 3-like protein secretion system to kill bacterial cells. Cell Rep. 40:


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