477 - Hijackers Hitchhike on Hyphal Highways

Phage stuck to non-host bacterium
By You et al, 2022,
ISMEJ 16:1275-1283
CC BY 4.0

This episode: Bacteriophages can hitch a ride on bacteria they don't infect to travel through soil on fungal filaments, potentially helping their carriers by infecting and killing their competitors!
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Show notes:
Microbe of the episode: Epinotia aporema granulovirus

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Takeaways

For tiny bacteria, partially dry soil can be like a vast system of caverns, with particles of soil separated by air-filled spaces much bigger than individual bacteria. Not all bacteria can swim through liquid, and those that can’t simply try to thrive as best they can wherever they may be. But for those that can swim, fungi and other filamentous organisms can form bridges between soil particles that motile bacteria can swim across, reaching new places.

In this study, phages were found to hitch a ride on bacteria they don’t normally infect, crossing fungus-like filaments to new places and infecting the bacteria they find there. The bacteria carrying them can also benefit from this interaction, since the phages help the carrier bacteria compete and establish a colony in the new location.

Journal Paper:
You X, Kallies R, Kühn I, Schmidt M, Harms H, Chatzinotas A, Wick LY. 2022. Phage co-transport with hyphal-riding bacteria fuels bacterial invasion in a water-unsaturated microbial model system. 5. ISME J 16:1275–1283.

Other interesting stories:

• Fungus species discovered in spacecraft assembly facility
• Oral microbes uniquely influence immune system interaction with mouth bones

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

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476 - Bamboo Breakdown Benefits Beetle Babies

Bamboo
By I Kenpei,
CC BY-SA 3.0

This episode: Beetles inoculate bamboo with a fungus that consumes the bamboo sugars to feed the beetle larvae!
Download Episode (7.7 MB, 11.2 minutes)

Show notes:
Microbe of the episode: Saccharomyces cerevisiae virus L-BC (La)

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Video: Lizard beetle laying its egg

Takeaways

The structural polymers that make up plants, such as cellulose, can be difficult for many organisms to digest. Some kinds of bacteria and fungi can do it, and some animals (cows, pandas, termites) partner with these microbes to be able to eat otherwise indigestible plant material. This includes insects such as leaf-cutter ants that farm external gardens of microbes, providing them plant material and then eating the resulting microbial growth.

In this study, the lizard beetle lays its eggs in bamboo and inoculates the walls of the bamboo with a fungus that provides food to the larvae. Chemical analyses suggest that the fungus only consumes the simple sugars in the bamboo rather than breaking down the tougher polymers, which raises questions about the evolution of this interaction.

Journal Paper:
Toki W, Aoki D. 2021. Nutritional resources of the yeast symbiont cultivated by the lizard beetle Doubledaya bucculenta in bamboos. Sci Rep 11:19208.

Other interesting stories:

• Using bacteria to detect and target colon cancer for imaging (paper)
• Filters made from kombucha cultures could work better than synthetic types

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

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475 - Modifying Mixed Microbiota

Escherichia coli

This episode: New techniques allow specific modifications in certain members of a complex community of microbes, without isolating them in pure culture first!
Download Episode (11.5 MB, 16.7 minutes)

Show notes:
Microbe of the episode: Tomato golden mosaic virus

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Takeaways

The technology for understanding and manipulating microbial genetics has come a long way in a short time. It used to take years even to sequence a small genome, and now thousands can be sequenced in just a few days. The technology to change and even create genetic sequences is also much further advanced now than just a few decades ago. But still, many analyses and modifications require a pure culture of a microbe to carry out.

This study tested a method for modification of single or multiple species in a community of many. The method allows for identification of which species were successfully modified in targeted ways, and can allow the modified species to be extracted and studied individually.

Journal Paper:
Rubin BE, Diamond S, Cress BF, Crits-Christoph A, Lou YC, Borges AL, Shivram H, He C, Xu M, Zhou Z, Smith SJ, Rovinsky R, Smock DCJ, Tang K, Owens TK, Krishnappa N, Sachdeva R, Barrangou R, Deutschbauer AM, Banfield JF, Doudna JA. 2022. Species- and site-specific genome editing in complex bacterial communities. 1. Nat Microbiol 7:34–47.

Other interesting stories:

• Microbes that degrade plastic may be increasing in response to plastic pollution
• Algae in ocean communicate with each other using fluorescence

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

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474 - Stalker Cells Stop Seafood Sickness

Halobacteriovorax predator cells
By Ooi et al, 2021,
Microbiology 167:001113
CC BY-NC

This episode: Predatory bacteria could protect lobster farms from disease-causing bacteria!
Download Episode (4.8 MB, 7 minutes)

Show notes:
Microbe of the episode: Gordonia rubripertincta

 

Takeaways

Antibiotics have done wonders for controlling bacterial pathogens. Many people have lived that would otherwise have died, and some industries have produced much more than they would have, particularly those involved in animal farming. However, more and more targeted pathogens are developing resistance to the antibiotics we have, and new ones are harder to discover, so alternative approaches are needed.

Here, predatory bacteria take the place of antibiotics in a study on farmed spiny lobsters. These predators swim after and attach to prey bacteria, hollowing out their contents to use as nutrients to make more predators. They do not hurt the lobsters, but the study finds they do reduce the number of pathogenic prey organisms injected into the lobsters at the same time.

Journal Paper:
Ooi MC, Goulden EF, Smith GG, Bridle ARY 2021. 2021. Predatory bacteria in the haemolymph of the cultured spiny lobster Panulirus ornatus. Microbiology 167:001113.

Other interesting stories:

• 3D-printing bacterial biofilms
• Review of latest in oncolytic (cancer-killing) viruses

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

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473 - Bacteriophage Bunks in Bacterial Barriers

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

 

This episode: A bacteriophage that overcomes the bacterial  CRISPR/Cas immune system by interrupting the CRISPR DNA with its own genome!
Download Episode (6.8 MB, 10 minutes)

Show notes:
Microbe of the episode: Wenzhou mammarenavirus

 

Takeaways

Bacteria have many ways to resist being exploited by bacteriophage viruses, including the adaptable CRISPR/Cas system that uses a piece of viral nucleic acid sequence to target and destroy incoming phages. But phages also have many ways to evade and disrupt bacterial defenses.

In this study, a phage is discovered that inserts its own genome into the CRISPR/Cas sequence in the bacterial genome, disrupting the bacterial defenses. To escape the defenses while it is doing this insertion, it carries genes for previously-unknown anti-CRISPR proteins. But inserting and removing a viral sequence from the bacterial genome is not always a clean procedure.

Journal Paper:
Varble A, Campisi E, Euler CW, Maguin P, Kozlova A, Fyodorova J, Rostøl JT, Fischetti VA, Marraffini LA. 2021. Prophage integration into CRISPR loci enables evasion of antiviral immunity in Streptococcus pyogenes. 12. Nat Microbiol 6:1516–1525.

Other interesting stories:

• Great article on the history of phage therapy

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

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472 - Caulobacter Condensates Compartmentalize Kinase

Caulobacter crescentus

This episode: Bacteria can use blobs of disordered proteins to quickly adapt to new conditions!

Thanks to Dr. Saumya Saurabh for his contribution!
Download Episode (10.9 MB, 15.9 minutes)

Show notes:
Microbe of the episode: Drosophila melanogaster Micropia virus

 

Takeaways

Bacteria can adapt to environmental fluctuations via mechanisms operating at the various levels of the central dogma, or metabolism (stringent response). Recently, researchers at Stanford University discovered a mechanism that allows bacteria to sense and rapidly adapt to nutrient fluctuations by simply tuning protein self-assembly as a function of nutrient availability. Termed membraneless organelles or condensates, these proteinaceous assemblies can dynamically sequester key signaling enzymes within them in response to environmental cues. Biophysical adaptation mediated by organelles is fast, reversible, and facile; thereby representing a crucial step in the mechanistic understanding of microbial adaptation.

Journal Paper:
Saurabh S, Chong TN, Bayas C, Dahlberg PD, Cartwright HN, Moerner WE, Shapiro L. 2022. ATP-responsive biomolecular condensates tune bacterial kinase signaling. Sci Adv 8:eabm6570.

Other interesting stories:

• Bacteria produce biofuel from carbon dioxide, light, and solar power-generated electricity
• Vine that can mimic leaves of different trees may get info from bacteria (paper)

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

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471 - Phage Fight Foils Fitness

Shigella phage A1-1
By Kortright et al., 2022.
AEM 2022, 88(e01514).
CC BY-4.0

This episode: A phage both kills bacterial pathogens and selects for reduced virulence!

Download Episode (6.3 MB, 9.9 minutes)

Show notes:
Microbe of the episode: Helminthosporium victoriae 145S virus

 

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Takeaways

Using bacteria-killing viruses to treat bacterial infections, or phage therapy, can be a good alternative to antibiotics in some situations when there are no effective antibiotics for a particular infection. But bacteria can evolve resistance to phages as well as antibiotics, often with little cost to their fitness.

In this study, a phage not only could treat an infection by attacking the bacteria, but the bacterial hosts that do evolve resistance to the phage do so by getting rid of certain structures that help them to cause more serious infection. Thus, therapy with this phage may both reduce the bacterial load and also make those remaining less virulent.

Journal Paper:
Kortright KE, Done RE, Chan BK, Souza V, Turner PE. 2022. Selection for Phage Resistance Reduces Virulence of Shigella flexneri. Appl Environ Microbiol 88:e01514-21.

Other interesting stories:

• Plastic-eating bacteria could produce biodegradable plastic
• Harmless variant of acne bacteria could help prevent more serious skin infection

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.