BacterioFiles 418 - Special Sea Species Swallows Cells

New microbe engulfing prey
By Shiratori et al. 2019
Nat Commun 10(1):1-11, CC BY 4.0

This episode: A newly discovered species of bacteria consumes other bacteria as prey by engulfing them!

Also a note to listeners: Because things are hectic at work right now (unless that changes due to current events), I'm planning to put the show on hold for a few weeks. So if you don't see new episodes, that's why.


Download Episode (8.7 MB, 12.6 minutes)

Show notes:
Microbe of the episode: SARS-CoV-2! This is the coronavirus responsible for COVID-19, the current pandemic. For more up-to-date information, please refer to the American Society for Microbiology, This Week in Virology, and other reputable sources. Stay healthy!

Takeaways
There are bacteria living almost every different lifestyle you can think of, including predatory, preying on other bacteria. Since bacterial cells are usually quite rigid, bacterial predators usually consume others either by burrowing inside them or digesting them from outside, rather than engulfing prey like eukaryotes often do.

The study here discovers a new kind of bacteria, in the group called Planctomycetes, known for having unusually flexible cells and internal compartments like eukaryotes. This new species does engulf its prey, including bacteria and even tiny algae, and digests them inside itself. It possesses multiple adaptations that suit it for this lifestyle.

Journal Paper:
Shiratori T, Suzuki S, Kakizawa Y, Ishida K. 2019. Phagocytosis-like cell engulfment by a planctomycete bacterium. Nat Commun 10:1–11.

Other interesting stories:

• Engineering a common industrial yeast strain to fix carbon dioxide (paper)
• Lake microbes convert microplastics into essential fatty acids

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

Subscribe: Apple Podcasts, Google Podcasts, Android, or RSS. Support the show at Patreon, or check out the show at Twitter or Facebook.

BacterioFiles 417 - Bacteriophage Blocks Bacterial Bouncers

Pseudomonas aeruginosa
By Y_tambe, CC BY-SA 3.0

This episode: A phage defends its genome against bacterial host defenses by building a wall to keep them out!


Download Episode (7.0 MB, 10.2 minutes)

Show notes:
Microbe of the episode: Myroides odoratus and M. odoratimimus

News item

Takeaways
Parasites and their hosts are constantly in arms races with each other, each thriving best when it acquires new and more effective methods of attack, defenses, defenses against defenses, and so on. Bacterial defenses against viruses that infect them mostly involve cutting up viral genomes, either by the indiscriminate specific-cutting restriction enzymes, or by adaptive, sequence-sensing CRISPR/Cas systems.

Bacteriophages have proteins that can defend against the CRISPR/Cas system, but they mostly require the sacrifice of multiple failed infections before the proteins build up enough to defeat the defense. In this study, a phage is discovered that can immediately defend against all DNA-cutting systems, by constructing a nucleus-like protective compartment inside the host.

Journal Paper:
Mendoza SD, Nieweglowska ES, Govindarajan S, Leon LM, Berry JD, Tiwari A, Chaikeeratisak V, Pogliano J, Agard DA, Bondy-Denomy J. 2020. A bacteriophage nucleus-like compartment shields DNA from CRISPR nucleases. Nature 577:244–248.

Other interesting stories:

• Helpful vaginal microbes inhibit HIV infection (paper)
• Engineering bacteria to fix nitrogen that grain plants can use (paper)

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

Subscribe: Apple Podcasts, Google Podcasts, Android, or RSS. Support the show at Patreon, or check out the show at Twitter or Facebook.

BacterioFiles 416 - Oxygen Or Other Oxidizes Iron?

Chlorobium phaeoferrooxidans

By Thompson et al, 2019.
Sci Adv 5:eaav2869.
CC BY-NC 4.0

This episode: Earth's iron deposits could have been created by anaerobic light-harvesting microbes instead of those that make oxygen!

Download Episode (9.3 MB, 13.5 minutes)

Show notes:
Microbe of the episode: Streptomyces avidinii

News item

Takeaways
In the ancient earth, the sun was dimmer, the world was colder, and oxygen was rare because photosynthesis had not yet evolved. Without oxygen to oxidize it, iron remained in its soluble, more accessible form, and many organisms took advantage of it for anaerobic metabolism.

But was it photosynthesis and the oxygen it created that transformed most of the planet's iron into its insoluble form, creating large iron deposits in the ground? This study explores the possibility that it was another form of light-harvesting metabolism, called photoferrotrophy, that uses light and the transformation of iron to generate energy. This hypothesis is found to be consistent with the evidence we have about what the early earth was like.

Journal Paper:
Thompson KJ, Kenward PA, Bauer KW, Warchola T, Gauger T, Martinez R, Simister RL, Michiels CC, Llirós M, Reinhard CT, Kappler A, Konhauser KO, Crowe SA. 2019. Photoferrotrophy, deposition of banded iron formations, and methane production in Archean oceans. Sci Adv 5:eaav2869.

Other interesting stories:

• Gut microbes help whales digest tricky fats in their diet
• Bacteria deliver antibiotic to competitors using capsules made of its own membrane (paper)

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

Subscribe: Apple Podcasts, Google Podcasts, Android, or RSS. Support the show at Patreon, or check out the show at Twitter or Facebook.