BacterioFiles

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

Email questions or comments to bacteriofiles at gmail dot com. Thanks for listening!

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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

Email questions or comments to bacteriofiles at gmail dot com. Thanks for listening!

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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.

Email questions or comments to bacteriofiles at gmail dot com. Thanks for listening!

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This episode: Actinomycete bacteria are often helpful to insects, but some can be deadly yet still attractive!

Download Episode (5.7 MB, 8.3 minutes) Show notes: Microbe of the episode: Streptomyces corchorusii

News item Takeaways Actinomycete bacteria do a lot of interesting things. They grow like fungi, with mycelia and spores, and produce many interesting compounds, including antibiotics and other useful pharmaceuticals. They often team up with insects, producing such compounds to assist them in competing with other organisms or resisting disease. But such amazingly helpful powers of chemistry can also be amazingly harmful. In this study, multiple strains of these bacteria were able to kill fruit fly larvae that ingested their spores. The toxin the bacteria produced was a chemical that interferes with cells' DNA-protein interactions. The bacteria also produced an odor that, in certain concentrations, lured the larvae to their doom. Journal Paper: Ho LK, Daniel-Ivad M, Jeedigunta SP, Li J, Iliadi KG, Boulianne GL, Hurd TR, Smibert CA, Nodwell JR. 2020. Chemical entrapment and killing of insects by bacteria. Nat Commun 11:4608.

Other interesting stories:

• Eukaryotes borrowed viperin genes for proteins that prokaryotes use to fight viruses (paper)
• Bacteria can break down plastic even faster with newly discovered enzyme

Also news, Feedspot ranked BacterioFiles in the top 5 virology podcasts! Check out the list for other good shows about viruses.

Email questions or comments to bacteriofiles at gmail dot 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.

This episode: Warmth helps mice build stronger bones, mediated by bacteria producing certain compounds!

Download Episode (6.8 MB, 9.9 minutes) Show notes: Microbe of the episode: Aquaspirillum serpens

News item Takeaways Bones aren't just solid, structural supports for the body's tissues. They're active and alive, housing important components of the immune system, and also capable of being broken down and built up in response to changes in the body's interactions with the environment. Various things can affect bone mass and health, including nutrition, temperature, age, and even the body's microbes. In this study, two of these effects are found to interact. Warmth leads to increased bone density in mice, and this effect can be attributed to the microbes in the mice, and transmitted from one mouse to another just by transplanting microbes adapted to warmth. Even the particular chemicals the microbes produce that mediate this effect are discovered. Journal Paper: Chevalier C, Kieser S, Çolakoğlu M, Hadadi N, Brun J, Rigo D, Suárez-Zamorano N, Spiljar M, Fabbiano S, Busse B, Ivanišević J, Macpherson A, Bonnet N, Trajkovski M. 2020. Warmth Prevents Bone Loss Through the Gut Microbiota. Cell Metab 32:575-590.e7.

Other interesting stories:

• Salt-tolerant bacteria could help plants grow in coastal areas (paper)
• Fire ants like to nest near potentially antifungal bacteria

Email questions or comments to bacteriofiles at gmail dot 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.

This episode: Copper electrodes, rather than killing bacteria in microbial fuel cells, allow them to generate higher densities of electric current!

Download Episode (5.0 MB, 7.2 minutes) Show notes: Microbe of the episode: Xipapillomavirus 2

News item Takeaways Copper is widely used as a way to make surfaces and materials antimicrobial, to cut down on the spread of pathogens in hospitals and other environments. Among other mechanisms, it reacts with oxygen to form reactive oxygen species that are very harsh on microbial proteins. But copper is also a good electrical conductor, which would be useful to use in microbial fuel cells, which exploit bacterial metabolism to generate electricity. Microbes form biofilms on an electrode and transfer electrons to it as a way for them to generate energy. Most such fuel cells have used graphite electrodes to avoid toxicity. In this study, fuel cell bacteria grew well on a copper electrode in an oxygen-free environment. The copper actually allowed them to increase the amount of current they produced per unit of area, as ionic copper diffused through the biofilm and allowed electrons to flow through the biofilm to the electrode from layers farther from the electrode that otherwise would not have access. Even graphite electrodes could be improved by adding these copper ions to the biofilm directly. Journal Paper: Beuth L, Pfeiffer CP, Schröder U. 2020. Copper-bottomed: electrochemically active bacteria exploit conductive sulphide networks for enhanced electrogeneity. Energy Environ Sci 13:3102–3109.

Other interesting stories:

• Lizard gut microbes are affected by temperature, and may affect lizard heat tolerance (paper)
• Phages in ice show evidence of trading genes easily to adapt to new environments

Email questions or comments to bacteriofiles at gmail dot 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.

This episode: Combining Salmonella with something called photoimmunotherapy to attack tumors in multiple ways!

Download Episode (8.2 MB, 11.9 minutes) Show notes: Microbe of the episode: Shimwellia blattae

Takeaways Distinguishing healthy from unhealthy tissue is one of the big challenges when dealing with cancer. Since cancer is derived from healthy tissue, there are many similarities between them that make it hard to target it specifically. This is especially important when cancer is spread in multiple places throughout the body, as opposed to a single tumor that can be removed locally. In this study, bacteria modified to make them safer were injected into mice with tumors. The bacteria alone were capable of doing some damage to the tumors, and this damage happened to make the tumors darker. Using this color change, the scientists targeted the tumors with lasers to heat them up and kill them in an isolated manner. This had the added benefit of inducing an immune response against the cancer that could target it throughout the body. Journal Paper: Yi X, Zhou H, Chao Y, Xiong S, Zhong J, Chai Z, Yang K, Liu Z. 2020. Bacteria-triggered tumor-specific thrombosis to enable potent photothermal immunotherapy of cancer. Science Advances 6:eaba3546.

Other interesting stories:

• Bacteria could help make nylon more sustainably
• Glowing bacteria living in nematodes that kill insects may also interact with and protect plant roots (paper)

Email questions or comments to bacteriofiles at gmail dot 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.

This episode: Large phage discovered that contains a compact version of the CRISPR/Cas defense/gene editing system!

Download Episode (5.9 MB, 8.6 minutes) Show notes: Microbe of the episode: Stenotrophomonas virus IME13

News item Takeaways CRISPR/Cas systems have made a lot of things in gene editing much easier in certain organisms. It's almost as easy as just getting the cells to produce the Cas protein and putting in an RNA sequence to tell it where to go! But in some cases, these requirements are too much to work well. In this study, a more compact version of CRISPR/Cas was discovered in large bacteriophages. These systems help the viruses compete with other viruses and defend against host defenses sometimes. The Cas protein is half the size of the standard Cas most used in gene editing, and it has fewer other requirements to function in new cells, so it could be better in versatility and potential in applications with strict space constraints. Journal Paper: Pausch P, Al-Shayeb B, Bisom-Rapp E, Tsuchida CA, Li Z, Cress BF, Knott GJ, Jacobsen SE, Banfield JF, Doudna JA. 2020. CRISPR-CasΦ from huge phages is a hypercompact genome editor. Science 369:333–337.

Other interesting stories:

• Example of how cooperation becomes more beneficial than independence
• Programming bacteria to detect and kill specific other microbes in a mixed community (paper)

Email questions or comments to bacteriofiles at gmail dot 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.

This episode: A probiotic can protect intestine-like cell growths from destruction by pathogens, but it can also be infected by a virus that makes it more harmful to intestinal cells!

Download Episode (6.9 MB, 10.1 minutes) Show notes: Microbe of the episode: Euphorbia yellow mosaic virus

News item Takeaways There are many strains of Escherichia coli. Some are pathogenic, in the gut or the urinary tract, and a subset of those are very dangerous, such as the enterohemorrhagic O157:H7 strain. Many others are commensals, living peacefully as part of our gut community. And some strains can be beneficial to the host, protecting from and reducing the severity of disease. One such strain is called E. coli Nissle. This study used an advanced model of human intestines called organoids, where stem cells are induced to develop into hollow spheres of intestinal epithelium in which all cell types of a normal intestinal wall are represented. E. coli pathogens typically destroy these organoids and escape from inside, but Nissle was able to prevent this destruction and enable coexistence between the pathogen and the host cells. Nissle suffered for this protection though; O157:H7 carries a toxin-encoding phage that can infect and kill susceptible E. coli strains. Those Nissle cells that survived this infection could resist the phage, but were not as beneficial to the organoids due to the toxin they now produced. Journal Paper: Pradhan S, Weiss AA. 2020. Probiotic Properties of Escherichia coli Nissle in Human Intestinal Organoids. mBio 11(4):e01470-20.

Other interesting stories:

• Certain gut microbes can help people resist cholera
• Photosynthetic microbes engineered to produce spider silk

Email questions or comments to bacteriofiles at gmail dot 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.

This episode: Bacteria living in the driest place on earth have ways to extract water from the mineral structures of rocks!

Download Episode (3.7 MB, 5.4 minutes) Show notes: Microbe of the episode: Irkut lyssavirus

News item Takeaways Microbes living in extremely dry conditions have it tough. Water is important both for the chemistry and structure of all cells. Desert microbes are very good at acquiring and holding on to the water they can find, but in places such as the Atacama Desert in Chile, there's almost none available. However, microbes can be very resourceful. In this study, phototrophs were discovered that can actually extract water molecules bound up in the crystalline structure of the mineral gypsum, and this allows them to survive in hyperarid regions. They do this by secreting organic acid molecules to etch the rock and release the water, converting gypsum to anhydrite, which is a mineral with the same chemical structure except without the water. Journal Paper: Huang W, Ertekin E, Wang T, Cruz L, Dailey M, DiRuggiero J, Kisailus D. 2020. Mechanism of water extraction from gypsum rock by desert colonizing microorganisms. Proc Natl Acad Sci 117:10681–10687.

Other interesting stories:

• Cholesterol-lowering drugs associated with fewer gut microbiota problems
• Using bacterial hormones to get bacteria to produce more interesting molecules

Email questions or comments to bacteriofiles at gmail dot 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.