468 - Commensal Can Kill Cholera

Vibrio cholerae

This episode: Harmless gut microbes resist cholera with good defense or better offense!

Download Episode (5.8 MB, 8.4 minutes)

Show notes:
Microbe of the episode: Streptomyces corchorusii

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Takeaways

The community of microbes in our guts is highly diverse, yet generally they all coexist relatively peacefully. Some pathogens can invade this community and cause massive disruptions. Cholera is a disease caused by a pathogen that injects its competing bacteria with toxins and disrupts the health of the gut, leading to very watery diarrhea that can quickly dehydrate victims.

This study found that some microbes commonly found harmlessly existing in the gut can resist destruction by the cholera pathogen. One of these resists by striking back with its own toxin injection system; the other creates a barrier of slime around itself that keeps the invader's toxins from reaching it. Such resistant gut microbes could help to reduce the threat of diseases such as cholera.

Journal Paper:
Flaugnatti N, Isaac S, Lemos Rocha LF, Stutzmann S, Rendueles O, Stoudmann C, Vesel N, Garcia-Garcera M, Buffet A, Sana TG, Rocha EPC, Blokesch M. 2021. Human commensal gut Proteobacteria withstand type VI secretion attacks through immunity protein-independent mechanisms. Nat Commun 12:5751.

Other interesting stories:

• Producing super-strong fibers with engineered microbes
• Some gut bacteria store some drugs inside their cells

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

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467 - Prion Pivots Productive Pathways

Saccharomyces yeast
By Mogana Das Murtey and
Patchamuthu Ramasamy
CC BY-SA 3.0

This episode: Prions in yeast can allow better adaptation to changing conditions!

Thanks to David Garcia for his contribution!

Download Episode (9.5 MB, 13.9 minutes)

Show notes:
Microbe of the episode: Hepatovirus F

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Takeaways

Prions can be deadly. They're misshapen proteins that cause a cascade of misfolding of similar proteins if they get into the nervous system, resulting in neurodegeneration in mammals. But in other organisms, they are not always so scary; some fungi use prions to regulate their behavior in varying conditions.

In this study, a prion allows yeast to switch between a fast-growing lifestyle with shorter reproductive lifespan that can be beneficial in conditions where nutrients are often plentiful, and a slower-growing but more enduring lifestyle that helps in more scarce conditions.

Journal Paper:
Garcia DM, Campbell EA, Jakobson CM, Tsuchiya M, Shaw EA, DiNardo AL, Kaeberlein M, Jarosz DF. 2021. A prion accelerates proliferation at the expense of lifespan. eLife 10:e60917.

Other interesting stories:

• Modified yeast probiotic could tune its effects as needed by sensing bowel inflammation

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

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466 - Microbes Mining Mars Minerals

Basalt close up
By Helgi, CC BY-SA 4.0

This episode: Bacteria are able to extract metals from rocks for industrial use, even in microgravity!

Download Episode (6.2 MB, 9.0 minutes)

Show notes:
Microbe of the episode: Decapod ambidensovirus 1

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Takeaways

As humanity makes progress toward becoming an interplanetary species, consideration is needed on how travelers can survive and thrive in distant places. These methods may look very different from what works well on Earth, with differences in gravity, atmosphere, and access to resources. For example, mining for materials for construction may not be feasible using methods common on Earth. An alternative may be biomining, using microbes that can selectively extract and purify specific metals from minerals.

In this study, the European Space Agency tested the ability of several microbes to extract vanadium from rocks in different gravity conditions, on the International Space Station. Two out of three microbes were able to extract twice as much vanadium as was extracted in the absence of microbes, both on a planet and up in space.

Journal Paper:
Cockell CS, Santomartino R, Finster K, Waajen AC, Nicholson N, Loudon C-M, Eades LJ, Moeller R, Rettberg P, Fuchs FM, Van Houdt R, Leys N, Coninx I, Hatton J, Parmitano L, Krause J, Koehler A, Caplin N, Zuijderduijn L, Mariani A, Pellari S, Carubia F, Luciani G, Balsamo M, Zolesi V, Ochoa J, Sen P, Watt JAJ, Doswald-Winkler J, Herová M, Rattenbacher B, Wadsworth J, Everroad RC, Demets R. 2021. Microbially-Enhanced Vanadium Mining and Bioremediation Under Micro- and Mars Gravity on the International Space Station. Front Microbiol 12:663.

Other interesting stories:

• A prokaryote with internal metabolic compartments (paper)

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

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465 - Partners Produce Predator Prevention

Fungus cells with 
bacterial symbionts
By Büttner et al. 2021
PNAS 118:e2110669118
CC BY-NC-ND 4.0

This episode: Bacteria living inside soil fungus produce toxins that can protect their host from tiny predators!

Download Episode (7.7 MB, 11.2 minutes)

Show notes:
Microbe of the episode: Mycobacterium virus DLane

Takeaways

Soils have many different organisms cooperating and competing for resources. Some little worms called nematodes prey on fungi in the soil, while fungi may effectively defend themselves or strike back with toxins or traps that catch and kill the worms. On top of these interactions are other organisms that interact in various ways. In this study, bacteria living inside a kind of soil fungus produce toxins that defend the fungus against predatory nematodes.

Journal Paper:
Büttner H, Niehs SP, Vandelannoote K, Cseresnyés Z, Dose B, Richter I, Gerst R, Figge MT, Stinear TP, Pidot SJ, Hertweck C. 2021. Bacterial endosymbionts protect beneficial soil fungus from nematode attack. Proc Natl Acad Sci 118:e2110669118.

Other interesting stories:

• Sequencing stomach bacteria to find out how prehistoric populations migrated

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

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464 - Prodding Pollen's Popping Process

Pollen
(fromWikipedia)

This episode: Certain nectar-dwelling bacteria can induce pollen to germinate to access their tasty proteins!

Download Episode (6.0 MB, 8.8 minutes)

Show notes:
Microbe of the episode: Clostridium oceanicum

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Takeaways

Nectar in flowers seems like it would be a great place for microbes to live, since it has so much sugar, but it's actually somewhat difficult to thrive solely in and on nectar. The carbon in sugar is only one essential element for life, and there's enough of it that it can be overwhelming to the osmotic balance of many microbes. Pollen could provide more nutrients in the form of protein and the nitrogen that comes with it, but it is difficult to penetrate its hard shell.

In this study, certain kinds of bacteria that live in nectar were able to access more pollen protein than other microbes by inducing pollen to germinate, growing out of its shell, or burst and release the protein directly. These microbes only benefited from pollen that were still alive and able to germinate, and not from those that had been disabled.

Journal Paper:
Christensen SM, Munkres I, Vannette RL. 2021. Nectar bacteria stimulate pollen germination and bursting to enhance microbial fitness. Curr Biol 31:4373-4380.e6.

Other interesting stories:

• Bacteria recycling plastic into vanilla flavor

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

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463 - Selectively Stimulating Cell Squatters

Bacteriophages
By Jancheva and Böttcher
2021, JACS 143:8344-8351
CC BY 4.0

This episode: Bacteria produce a compound that causes a phage lurking in the genome of a competing species to wake up and start killing that competitor!

Download Episode (8.2 MB, 12.0 minutes)

Show notes:
Microbe of the episode: Zaire ebolavirus

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Takeaways

Some bacteriophages infect and immediately destroy their hosts in a burst of new viruses, while others can be stealthier, integrating their genome into the genome of the host and remaining there quietly even over multiple generations of the bacteria. When something stresses the host, such as DNA damage, these integrated phages (prophages) become active and start producing new viruses, killing their host like the other kind does.

In this study, one kind of bacteria release a chemical that wakes up phages in a competitor species of bacteria. This is helpful for competition, but even more interesting is that out of the six prophages in the competitor species, the chemical wakes up only one of them. Such selective phage induction could be interesting to study.

Journal Paper:
Jancheva M, Böttcher T. 2021. A Metabolite of Pseudomonas Triggers Prophage-Selective Lysogenic to Lytic Conversion in Staphylococcus aureus. J Am Chem Soc 143:8344–8351.

Other interesting stories:

• Lab-evolved fungus strain could protect honeybees from mites

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462 - Super Ciliate Symbiont Set

Pseudoblepharisma tenue
By Muñoz-Gómez et al, 2021,
Sci Adv 7:eabg4102, CC BY 4.0

This episode: A eukaryote has symbionts living in it: green algae and also purple bacteria, a combo never seen before!

Download Episode (6.1 MB, 8.8 minutes)

Show notes:
Microbe of the episode: Staphylococcus virus phiETA

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Takeaways

Having bacteria as endosymbionts is fairly common in life on Earth: almost all eukaryotes have them in the form of mitochondria and sometimes chloroplasts. These former bacteria somehow got inside the ancestral eukaryote, either as parasites or as prey, and ended up as integral parts of their host's metabolic functions. Some organisms, especially insects, obtained bacterial endosymbionts more recently, that help them balance their metabolic needs when living on limited diets.

Algae have been known to be endosymbionts also, performing photosynthesis for their host. But in this study, a ciliate with both algae and purple photosynthetic bacteria as endosymbionts was discovered. Purple bacteria as symbionts is rare, and this combination has not been observed before. Interestingly, though algae produce oxygen through their photosynthesis, the ciliate prefers living in low-oxygen sediment at the bottom of a pond. The symbionts and their host seem to adjust their metabolisms as needed depending on the needs at the time; they may each perform photosynthesis, fermentation, or respiration if light, organic carbon, or oxygen are available.

Journal Paper:
Muñoz-Gómez SA, Kreutz M, Hess S. 2021. A microbial eukaryote with a unique combination of purple bacteria and green algae as endosymbionts. Sci Adv 7:eabg4102.

Other interesting stories:

• Oxygen-producing microbes could help treat acute strokes

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.