Microbiology Editor’s Choice: mechanisms of phage-induced membrane vesicle release

Posted on May 26, 2021   by Microbiology Society

Each month, a manuscript published in our flagship journal Microbiology is chosen by a member of the Editorial Board. This month, the paper is titled Bacteriophage infection of Escherichia coli leads to the formation of membrane vesicles via both explosive cell lysis and membrane blebbing’ and was chosen by Professor Riccardo Manganelli.  

Membrane vesicles (MVs) are spherical nanoparticles derived from bacterial membranes. They are very abundant in nature and have different functions, as diverting phages or host defence factors from bacterial cells, or transport specific cargo. However, despite their importance, MVs mechanisms of formation are still not completely understood. Using live super-resolution microscopy, this paper shows that lytic bacteriophages can induce MVs formation in Escherichia coli through two different mechanisms: explosive cell lysis and membrane blebbing, suggesting a major role of bacteriophages in the abundance of MVs in the environment, and opening new perspectives in the possibility to produce MVs for biotechnological purposes. 

Bacteriophage infection of Escherichia coli leads to the formation of membrane vesicles via both explosive cell lysis and membrane blebbing 

Extracellular membrane vesicles are nano-sized, membrane bound spheres that are produced by all domains of life, including both Gram-negative and Gram-positive bacteria. The mechanisms by which bacterial membrane vesicles are formed are not well understood. In this study we observed that E. coli cultures infected with the lytic bacteriophage T4 and T7 had abundant membrane vesicles compared to uninfected cultures.  We used live-cell super-resolution microscopy to follow the fate of E. coli cells infected with these bacteriophages and observed two modes of membrane vesicle formation – explosive cell lysis that shatters membranes into fragments that rapidly circularise into vesicles; and blebbing of the outer -membrane from intact cells. Our observations highlight the possibility that bacteriophage may be an important contributor to the abundance of membrane vesicles in nature. 

We spoke with the corresponding author Professor Cynthia Whitchurch to find out more: 

What is your institution and how long have you been there?  

 I am currently at the Quadram Institute Bioscience where I have been for almost two years. Prior to my move to the UK, I was at the iThree institute at the University of Technology Sydney for 12 years where this study was carried out.  

What is your research area?   

Bacterial lifestyles. 

What inspired you to research this topic?   

Observing bacteria under a microscope and seeing various fascinating phenomena that made me want to know what is going on, how and why. 

What is the most rewarding part of your research?  

Exploiting our understanding of bacterial behaviours to develop novel approaches to prevent and treat infection. 

What would you be doing if you weren't a scientist?  

Doggy day care. 

Follow Cynthia and co-authors Pappuk Mandal and Laura Nolan on Twitter.