Monday, August 12, 2019

BacterioFiles 393 - Prokaryote Partner Prevents Pathogen Potency

Acanthamoeba
By J Lorenzo-Morales et al. (2015).
Parasite 22: 10, CC BY 4.0
This episode: Bacterial symbionts of amoebas help them survive bacterial infection, and prevent pathogens from spreading to others as much!

Download Episode (7.5 MB, 8.1 minutes)

Show notes:
Microbe of the episode: Eubacterium dolichum

News item

Takeaways
Amoebas are free-living, single-celled organisms, but they have some things in common with some cells of our immune system (macrophages). For example, certain bacterial pathogens can infect both in similar ways. So it can be useful to study the interactions of amoebas and bacteria to learn about our own immune defenses.

In this study, the amoeba Acanthamoeba castellanii has another bacterial symbiont that helps it resist killing by the bacterial pathogen Legionella pneumophila. Once the amoebas recovered from the infection, they were more resistant to future challenges. Even better, the symbiont prevented the pathogen from transforming into a more spreadable form like it does when infecting amoebas alone.

Journal Paper:
König L, Wentrup C, Schulz F, Wascher F, Escola S, Swanson MS, Buchrieser C, Horn M. 2019. Symbiont-Mediated Defense against Legionella pneumophila in Amoebae. mBio 10:e00333-19.

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Post questions or comments here or email to bacteriofiles@gmail.com. Thanks for listening!

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Floor Fungi Fracture Phthalates

Monday, August 5, 2019

BacterioFiles 392 - Magnetic Microbes Maneuver Marine Manager

Calkinsia aureus
By djpmapleferryman
Uploaded by Shureg, CC BY 2.0
This episode: A marine protist can orient itself along magnetic fields thanks to bacterial symbionts on its surface that make magnetic nanoparticles!

Download Episode (7.2 MB, 7.9 minutes)

Show notes:
Microbe of the episode: Chlorocebus pygerythrus polyomavirus 3

Takeaways
Various kinds of bacteria can orient their movement along a magnetic field. These are called magnetotactic, and they use this ability to swim toward or away from the surface of their aquatic habitat, to adjust their oxygen exposure according to their preference.

No eukaryotic microbes have yet been discovered that can sense and react to magnetic fields like these prokaryotes. In this study, however, a protist was discovered that can do it via its partnership with ectosymbionts, or bacteria attached to its surface, that sense magnetism and orient their host's movement. In return, factors of the host's metabolism may feed its symbionts.

Journal Paper:
Monteil CL, Vallenet D, Menguy N, Benzerara K, Barbe V, Fouteau S, Cruaud C, Floriani M, Viollier E, Adryanczyk G, Leonhardt N, Faivre D, Pignol D, López-García P, Weld RJ, Lefevre CT. 2019. Ectosymbiotic bacteria at the origin of magnetoreception in a marine protist. Nat Microbiol 4:1088–1095.

Other interesting stories:

Post questions or comments here or email to bacteriofiles@gmail.com. Thanks for listening!

Subscribe: Apple Podcasts, RSS, Google Play. Support the show at Patreon, or check out the show at Twitter or Facebook.
Floor Fungi Fracture Phthalates