445 - Living Lurking Landmine Locators

Bioluminescence over landmine
By Shemer et al. 2020,
Microb Biotechnol
CC BY-NC

This episode: Engineered bacteria encapsulated in little beads sense chemicals from landmines and give off light!

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Show notes:
Microbe of the episode: Bifidobacterium pullorum

Takeaways

Landmines are a good way to take an enemy by surprise and do some damage. They're so good that some places in the world still aren't safe to go decades after a conflict, due to intact landmines hidden in the area. In order to detect them from a distance to aid in disarming efforts, we need something very good at detecting the faint odor they give off—something like bacteria!

In this study, bacteria are engineered to detect breakdown products of TNT in landmines and produce light—bioluminescence. These bacteria are encapsulated in polymer beads and are stable for months in the freezer, and could accurately pinpoint a landmine buried in sand for a year and a half.

Journal Paper:
Shemer B, Shpigel E, Hazan C, Kabessa Y, Agranat AJ, Belkin S. Detection of buried explosives with immobilized bacterial bioreporters. Microb Biotechnol https://doi.org/10.1111/1751-7915.13683.

Other interesting stories:

• Wastewater treatment plant could power itself from electricity produced by microbes
• Microbial exposures correlate with presence or lack of allergies in both people and their dogs

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

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444 - Strange Sequence Stops Cell Subjugation

T4 Bacteriophage
By Victoramuse,
CC BY-SA 4.0

This episode: An interesting bacterial genetic element protects against viruses in a unique way!

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Show notes:
Microbe of the episode: Mongoose associated gemykibivirus 1

News item

Takeaways

Even single-celled, microscopic organisms such as bacteria have to deal with deadly viruses infecting them. And while they don't have an immune system with antibodies and macrophages like we do, they still have defenses against infection, mostly based on sensing and destroying viral genomes. Restriction enzymes cut viral genomes at specific places, and CRISPR/Cas targets and destroys specific viral sequences. Knowing this, when microbiologists contemplate a strange genetic element of unknown function in bacteria, it's worth considering that it may be relevant to defense against phages.

The strange element in this case is retrons: a special reverse transcriptase enzyme takes a short non-coding RNA transcript and transcribes it into DNA, then links the RNA and DNA sequences together. These retrons are found in a variety of forms in a variety of microbes, and their function has been unknown up till now. In this study, one specific retron was found to defend bacteria against a number of phages. By comparing viruses, they discovered that this retron functions by sensing viruses' attempts to defeat another bacterial defense, a sort of second level of defenses. How common such a system is, what variants may exist, and how we may be able to use it for research or biotech purposes remain to be determined.

Journal Paper:
>Millman A, Bernheim A, Stokar-Avihail A, Fedorenko T, Voichek M, Leavitt A, Oppenheimer-Shaanan Y, Sorek R. 2020. Bacterial Retrons Function In Anti-Phage Defense. Cell 183:1551-1561.e12.

Other interesting stories:

• Bacteria can make biodegradable plastics from waste sludge

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443 - Gut Group Gives Gamma Guard

Lachnospiraceae
By Public Health Image Library
Attribution

This episode: Certain gut microbes protect mice from harmful effects of high-energy radiation!

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Show notes:
Microbe of the episode: Solenopsis invicta virus-1

News item

Takeaways

High-energy radiation can be very dangerous. Besides a long-term increased risk of cancer due to DNA damage, a high enough dose of radiation can cause lethal damage to multiple systems in the body, especially the gastrointestinal tract and the immune system. Finding new ways to treat or prevent damage from radiation would be very helpful for improving the safety of space travel, nuclear energy, and radiotherapy for cancer.

In this study, some mice exposed to a typically lethal dose of radiation survived without ill effects, thanks to certain microbes in their gut. Transferring these microbes to other mice helped those mice survive radiation as well, and even just the metabolites that the bacteria produced were helpful for protecting the cells in the body most affected by radiation.

Journal Paper:
Guo H, Chou W-C, Lai Y, Liang K, Tam JW, Brickey WJ, Chen L, Montgomery ND, Li X, Bohannon LM, Sung AD, Chao NJ, Peled JU, Gomes ALC, van den Brink MRM, French MJ, Macintyre AN, Sempowski GD, Tan X, Sartor RB, Lu K, Ting JPY. 2020. Multi-omics analyses of radiation survivors identify radioprotective microbes and metabolites. Science 370:eaay9097.

Other interesting stories:

• Algae incorporated into 3D-printed human tissues for research can provide oxygen for cells
• Bacteria in sea squirts produce potentially useful antifungal compound

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442 - Fossil Phototroph Phagocytosis

Fossilized coccolithophores
By Gibbs et al. 2020
Sci Adv 6:eabc9123
CC BY-NC 4.0

This episode: Algae surviving impact that killed the dinosaurs seem to have consumed other organisms to make it through the dark times!

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Show notes:
Microbe of the episode: Chaetoceros tenuissimus RNA virus 01

News item

Takeaways

Being able to look through time and learn about what might have happened to creatures throughout Earth's history is what makes paleontology great. Everyone knows about dinosaurs and what happened to them at the end of the Cretaceous period thanks to science. But what we can learn is not limited just to large organisms; there are ways to learn about microorganisms of the past as well, including by looking at fossils!

In this study, fossils of hard-shelled algae from around the end of the dinosaurs show that many of these microbes in the oceans went extinct at the same time due to the massive space impact. Debris blocked out sunlight for years, making it difficult for photosynthetic organisms to survive. So some of these algae appear to have survived by preying on smaller organisms, pulling them in through a hole in their shell.

Journal Paper:
Gibbs SJ, Bown PR, Ward BA, Alvarez SA, Kim H, Archontikis OA, Sauterey B, Poulton AJ, Wilson J, Ridgwell A. 2020. Algal plankton turn to hunting to survive and recover from end-Cretaceous impact darkness. Sci Adv 6:eabc9123.
Other interesting stories:

• Phages could help treat diabetic wound infections without harming microbiota (paper)

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441 - Hyphal Hijacker Helps Harvests

Fungus growing in root
By Zhang et al. 2020
Molec Plant 13:1420-1433
CC BY-NC-ND 4.0

This episode: A fungus-infecting virus transforms the fungal foe into a friend of its host plant!

Download Episode (6.1 MB, 8.9 minutes)

Show notes:
Microbe of the episode: Hepacivirus J

News item

Takeaways

Viruses can be useful for treating various diseases, especially bacterial infections and cancer. Their ability to target certain cell types specifically makes them great at hunting down and killing disease-causing cells without harming the body's healthy tissue. And just as bacteriophages can work to treat bacterial disease in us, fungal viruses could help to treat serious fungal infections in crop plants.

In this study, a fungus-infecting virus goes beyond treating a deadly fungal disease in rapeseed plants. Fungus infected with this virus no longer causes disease, but lives in harmony with the host plant, protects it from other fungal diseases, and even helps it to grow better.

Journal Paper:
Zhang H, Xie J, Fu Y, Cheng J, Qu Z, Zhao Z, Cheng S, Chen T, Li B, Wang Q, Liu X, Tian B, Collinge DB, Jiang D. 2020. A 2-kb Mycovirus Converts a Pathogenic Fungus into a Beneficial Endophyte for Brassica Protection and Yield Enhancement. Mol Plant 13:1420–1433.

Other interesting stories:

• Engineering E. coli to turn carbon dioxide into biomass
• Radiation super-resistant bacteria survive 1 year exposed to low Earth orbit

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

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440 - Prokaryotes Pay for Passage

Bacteria along fungal hyphae
By Abeysinghe et al. 2020,
Life Sci Alliance 3:e202000878
CC BY 4.0

This episode: Bacteria pay for the privilege of cruising around soil on fungus filaments!

Download Episode (7.7 MB, 11.2 minutes)

Show notes:
Microbe of the episode: Clostridium acetobutylicum

News item

Takeaways

In the complex environment of soil, many different kinds of organisms coexist. Some compete with each other, while others cooperate in fascinating interactions. One example is how bacteria can swim through a film of water surrounding the filaments of fungi, allowing them to traverse more quickly and reach new locations.

In this study, an interaction between fungus and bacterium is discovered in which the bacteria benefit from the fungus in enhanced ability to travel, and the fungus benefits by absorbing vitamins that the bacteria produce.

Journal Paper:
Abeysinghe G, Kuchira M, Kudo G, Masuo S, Ninomiya A, Takahashi K, Utada AS, Hagiwara D, Nomura N, Takaya N, Obana N, Takeshita N. 2020. Fungal mycelia and bacterial thiamine establish a mutualistic growth mechanism. Life Sci Alliance 3(12):202000878.

Other interesting stories:

• Honeybee gut microbes help them define their social groupings
• Smells that cheese fungi make help cheese microbe community develop

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

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439 - Microbes Mitigate Mushroom Morbidity

Button mushrooms
By chris_73, CC BY-SA 3.0

This episode: Bacteria protect farmed mushrooms from damage by other bacteria by breaking down their toxins!

Download Episode (4.9 MB, 7.1 minutes)

Show notes:
Microbe of the episode: Tomato mosaic virus

Takeaways

Almost all organisms are vulnerable to pathogenic microbes that make them sick or cause damage. Most also have other microbes that help them grow better or protect them from pathogens. This includes animals, plants, and also fungi.

In this study, bacterial pathogens produce a toxin that causes button mushrooms to turn brown and rot. However, other bacteria can degrade this toxin and protect the fungus, and can also degrade molecules the pathogens produce to help them swarm to new places, restricting their movement.

Journal Paper:
Hermenau R, Kugel S, Komor AJ, Hertweck C. 2020. Helper bacteria halt and disarm mushroom pathogens by linearizing structurally diverse cyclolipopeptides. Proc Natl Acad Sci 117:23802–23806.

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.