Acyl-Homoserine Lactones Can Induce Virus Production in Lysogenic Bacteria: an Alternative Paradigm for Prophage Induction

作者：Ghosh Dhritiman; Roy Krishnakali; Williamson Kurt E; Srinivasiah Sharath; Wommack K Eric; Radosevich Mark

来源：Applied and Environmental Microbiology, 2009, 75(22): 7142-7152.

DOI：10.1128/AEM.00950-09

<jats:title>ABSTRACT</jats:title>
<jats:p>
Prophage typically are induced to a lytic cycle under stressful environmental conditions or when the host's survival is threatened. However, stress-independent, spontaneous induction also occurs in nature and may be cell density dependent, but the in vivo signal(s) that can trigger induction is unknown. In the present study, we report that acyl-homoserine lactones (AHL), the essential signaling molecules of quorum sensing in many gram-negative bacteria, can trigger phage production in soil and groundwater bacteria. This phenomenon also was operative in a λ lysogen of
<jats:italic>Escherichia coli</jats:italic>
. In model coculture systems, we monitored the real-time AHL production from
<jats:italic>Pseudomonas aeruginosa</jats:italic>
PAO1 using an AHL bioluminescent sensor and demonstrated that λ-prophage induction in
<jats:italic>E. coli</jats:italic>
was correlated with AHL production. As a working model in
<jats:italic>E. coli</jats:italic>
, we show that the induction responses of λ with AHL remained unaffected when
<jats:italic>recA</jats:italic>
was deleted, suggesting that this mechanism does not involve an SOS response. In the same λ lysogen we also demonstrated that
<jats:italic>sdiA</jats:italic>
, the AHL receptor, and
<jats:italic>rcsA</jats:italic>
, a positive transcriptional regulator of exopolysaccharide synthesis, are involved in the AHL-mediated induction process. These findings relate viral reproduction to chemical signals associated with high host cell abundance, suggesting an alternative paradigm for prophage induction.
</jats:p>

• 出版日期2009-11-15