It's complicated: relationships between integrative and conjugative elements and their bacterial hosts

Area of Science:

• Microbiology
• Bacterial Genetics
• Mobile Genetic Elements

Background:

• Integrative and conjugative elements (ICEs) are mobile genetic elements residing within bacterial chromosomes.
• ICEs can confer advantageous traits like antibiotic resistance or pathogenesis factors to host bacteria.
• ICEs possess the ability to excise, replicate, and transfer between bacterial cells.

Purpose of the Study:

• To review the complex interactions between ICEs and their bacterial hosts.
• To highlight recent findings on the costs imposed by ICEs on host cells, including cell death.
• To contrast ICE-host killing mechanisms and their impact on conjugation.

Main Methods:

• Literature review of recent studies on ICEs and host interactions.
• Analysis of specific ICE examples like ICEclc and Tn916.
• Discussion of the implications of ICE activity on bacterial populations.

Main Results:

• At least three ICEs (ICEclc, Tn916, TnSmu1) can induce host cell death upon activation.
• ICE-mediated killing can either benefit (ICEclc) or impair (Tn916) conjugation.
• ICEs are typically active in a small fraction of the host population, influencing observed phenotypes.

Conclusions:

• ICE-host interactions involve significant costs, including host cell death.
• The impact of ICE-induced killing on conjugation varies depending on the specific ICE.
• Understanding these complex relationships is vital for comprehending bacterial evolution and mobile element dynamics.