Bacteriophage at mucosal sites help keep bacteria at bay


Scientists recently described a new form of symbiosis at our mucosal sites with an unassuming partner: bacteriophage. In a paper published in PNAS, Jeremy Barr and colleagues noticed that phage are enriched at mucosal surfaces compared to surrounding surfaces and demonstrated that a specific interaction between Ig-like domains on the phage capsid and mucin glycans is what holds them in place. Their findings suggest that the presence of phage in mucin protects the underlying epithelial cells from bacterial infection, a good reason for us to have evolved to keep them there. The relationship benefits the phage too – mucosal sites are a buffet of bacteria for the phage to infect and multiply within.

Join us at the Pheonix next Friday May 31st at 1 PM for a discussion over drinks about our friendly phage.

Here are some reasons we chose this paper and a few things to think about for discussion:

• It’s important to consider the diversity of microorganisms in our microbiome and their interactions with each other and the host in order to understand the ecosystem. Given phage specificity for certain bacterial species, does our virome change with fluctuations in bacterial communities? How does this alter community dynamics? (Interesting read on virome research: The other microbiome)

• We’ve coerced bacteriophage to act as our microscopic army against invading pathogens. It’s a strategy that not only humans, but also other metazoans with mucosal sites use as a strategy to defend against infection. But bacteria are smart too and aren’t content with the short end of the stick. They have their own defense against phages – the CRISPR/Cas systems. Recently this system is also implicated in bacterial virulence and immune evasion. Have our friendly phage contributed to pathogen evolution?

If you’re not able to make it, but are equally as fascinated with our inner viromes as we are, check out these links for more info and check back for a follow-up post on our discussion.

Carl Zimmer, The Loom: Meet your new symbionts: Trillions of Viruses

Ed Yong, Nature News: Viruses in the gut protect from infection 

Story behind the paper by Jeremy Barr, The Tree of Life

Bacteriophage Paper: Barr, J. J. et al. Proc. Natl. Acad. Sci. USA (2013)


About Julie Kaiser

Microbiology graduate student at McMaster University. I study the immune response to commensals in the human airways. @jukais
This entry was posted in journal club, Microbe of the week and tagged , , , , , . Bookmark the permalink.

2 Responses to Bacteriophage at mucosal sites help keep bacteria at bay

  1. Jen Stearns says:

    A lively discussion ensued (transcript We’d like to continue the discussion on the impact of phage on host health, microbial communities and microbial adaptation soon with another phage-specific talk.

  2. Pingback: Did You Know that Viruses are Saving Your Life Right Now? — State of Globe

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