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Biozentrum Lecture 2018

A phage that counts

Prof. Bonnie L. Bassler, Squibb Professor and Chair in Molecular Biology at Princeton University and Howard Hughes Medical Institute Investigator, USA

October 26, 2018, 12:15 pm Pharmazentrum, Lecture Hall 1

The causative agent of the acute intestinal disease cholera is the bacterium Vibrio cholerae. Key to its success as a pathogen is the ability to form surface attached biofilms. The formation and dispersal from biofilms is controlled by the bacterial cell-cell communication process called quorum sensing. The quorum-sensing system of V. cholerae involves the receptor VqmA and the signaling molecule DPO. When DPO binds to the receptor, it triggers the pathogen to repress biofilm formation and promotes dispersal from the human host.

While the signaling molecule DPO is widely produced in the bacterial world, the receptor VqmA is encoded specifically by vibrios. Recently, the team of Bonnie Bassler found that also a bacteriophage expresses the VqmA receptor and that DPO acts as a quorum-sensing signal. In phage-infected cholera bacteria, DPO activates phage replication and killing programs leading to the spread of virus infection and the death of the V. cholerae host population. This is the first report of a phage-encoded receptor that senses a host-produced, quorum-sensing molecule to mediate the decision between the two cycles of viral reproduction: the lysogenic and the lytic cycle. This “one-sided conversation” could enable the phage to influence host quorum sensing while executing its own lifestyle programs without interference of the bacterial host.

Based on this knowledge, the scientists developed a phage modular system by reprogramming phages to be DPO insensitive but responsive to user-defined cues. These reprogrammable phage modules that act as “kill switches” are potentially useful for environmental, industrial and medical applications.   


Bonnie L. Bassler is Squibb Professor and Chair in Molecular Biology at Princeton University and a Howard Hughes Medical Institute Investigator. She received her PhD in Biochemistry from the Johns Hopkins University. After postdoctoral work at the Agouron Institute, she joined the Princeton faculty in 1994. The American microbiologist is well known for her work on bacterial communication. Bassler has been awarded several prizes including the Shaw Prize in Life Science and Medicine, the Wiley Prize in Biomedical Sciences, the Dickson Prize in Medicine and is a Fellow of the Royal Society.