490 - Parasitoid Pox Partners

Caterpillar with
parasitoid coccoons
By Jesse Noar
CC BY 4.0

This episode: A virus partners with a parasitoid wasp to help exploit fruit fly victims!
Download Episode (7.7 MB, 11.2 minutes)

Show notes:
Microbe of the episode: Actinomadura livida

Takeaways

Parasitoid wasps have an interesting lifestyle: they inject their eggs into the larvae of other insects, and their young hatch and grow up by consuming the host from the inside. Some of these wasps also inject a virus along with the egg, which supports the wasp offspring by suppressing the host immune system.

Most of these parasitoid helper viruses are integrated into the host wasp genome and are translated and produced as needed, but in this study, an independently replicating entomopoxvirus serves as an example of a virus-wasp mutualism. The study explores how the virus can infect the wasp prey, and how it gets passed on to wasp offspring.

Journal Paper:
Coffman KA, Hankinson QM, Burke GR. 2022. A viral mutualist employs posthatch transmission for vertical and horizontal spread among parasitoid wasps. Proc Natl Acad Sci 119:e2120048119.

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489 - Soil Smell Synthesis Significance

C. elegans nematode
By Bob Goldstein
UNC Chapel Hill
CC BY-SA 3.0

This episode: Many organisms produce the smell of earth, geosmin, and many others can sense it–but why?
Download Episode (6.0 MB, 8.7 minutes)

Show notes:
Microbe of the episode: Acidianus spindle-shaped virus 1

 

News item

 

Takeaways

The smell of soil or earth is one of the most recognizable smells, and comes largely from a chemical called geosmin, produced by many different kinds of bacteria. Many animal species are sensitive to geosmin, some attracted by it and others repelled. But it is still not entirely understood what is the evolutionary benefit to the microbes that produce it, or the reason why different animals are sensitive to it in different ways.

In this study, different geosmin-producing bacteria were paired with tiny bacteria-eating roundworms, nematodes, to see how the chemical affected their interactions. Production of geosmin affected the worms' movement, apparently inducing them to avoid colonies of the producing microbes in some cases, though the worms still sometimes fed on the bacteria. Adding geosmin to colonies of different bacteria did not affect the worms' behavior though, so other factors seem to be involved.

Journal Paper:

Zaroubi L, Ozugergin I, Mastronardi K, Imfeld A, Law C, Gélinas Y, Piekny A, Findlay BL. 2022. The Ubiquitous Soil Terpene Geosmin Acts as a Warning Chemical. Appl Environ Microbiol 88:e00093-22.

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487 - Probiotic Pulverizes Pathogen Persisters

E. coli

This episode: A probiotic strain of E. coli can target and destroy pathogens that survive a treatment of antibiotics!
Download Episode (8.2 MB, 12 minutes)

Show notes:
Microbe of the episode: Streptomyces griseoruber

 

Takeaways

Antibiotic resistance is becoming more and more of a problem as bacterial pathogens develop resistance to more and more drugs. For some people who develop an infection that is resistant to everything, it's as if they were living back in the days before antibiotics were discovered, when all they could do was pray for survival. New antibiotics are needed, but even more needed are new ways of approaching treatment of infections, using innovative approaches and combinations of therapeutics.

In this study, a probiotic strain of Escherichia coli was used to target potentially pathogenic E. coli bacteria that can survive treatment with a particularly effective type of antibiotic, fluoroquinolones. This probiotic strain, called Nissle, delivers toxins directly to the survivors, preventing resistant pathogens from proliferating.

Journal Paper:
Hare PJ, Englander HE, Mok WWK. 2022. Probiotic Escherichia coli Nissle 1917 inhibits bacterial persisters that survive fluoroquinolone treatment. J Appl Microbiol 132:4020–4032.

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484 - Bacteriophages Boost Brains

Lysogenic phage
By Rolf Lood et al.
BMC Microbiology
2008, 8:139
CC BY 2.5

This episode: Certain phages in the gut are linked with increases in performance on some cognitive tests!
Download Episode (7.5 MB, 10.9 minutes)

Show notes:
Microbe of the episode: Streptomyces bikiniensis

News item

Takeaways

Our gut microbiota includes a large number of viruses, mostly bacteriophages. These fall into two groups, the lytic kind that infects and reproduces itself immediately in a host, and the lysogenic kind that can integrate its genome into the host bacterial genome and remain dormant for long periods.

In this study, a higher proportion of lysogenic phages was correlated with increased performance on cognitive tests in multiple species. In humans, men showed a small increase in some tests and women in others. In mice and fruit flies, transplant or ingestion of phages was linked to increased memory performance.

Journal Paper:
Mayneris-Perxachs J, Castells-Nobau A, Arnoriaga-Rodríguez M, Garre-Olmo J, Puig J, Ramos R, Martínez-Hernández F, Burokas A, Coll C, Moreno-Navarrete JM, Zapata-Tona C, Pedraza S, Pérez-Brocal V, Ramió-Torrentà L, Ricart W, Moya A, Martínez-García M, Maldonado R, Fernández-Real J-M. 2022. Caudovirales bacteriophages are associated with improved executive function and memory in flies, mice, and humans. Cell Host Microbe 30:340-356.e8.


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480 - Bait Bottlenecks Bear Bacteria

Black bear
By Diginatur
CC BY-SA 3.0

This episode: Human-based food used as bait by hunters can reduce bears' gut microbe diversity!
Download Episode (5.9 MB, 8.6 minutes)

Show notes:
Microbe of the episode: Actinomadura verrucosospora

News item

Takeaways

Gut microbes are important for the health of most animals. In humans, many things can affect our gut microbe community, including diet, medications, and lifestyle. Eating a varied diet with diverse kinds of plant-based foods can maintain a healthy, functional community of many different kinds of microbe. However, eating mostly highly processed grain-based foods can reduce the diversity and functionality of the gut community.

This is also true in bears. In this study, when bears consumed more processed, grain-based human foods via hunters leaving such foods out as bait, the gut communities in these bears had reduced diversity of microbes. The effects of this reduced diversity were not determined, but it is reasonable to assume it was not good for the bears’ overall health.

Journal Paper:
Gillman SJ, McKenney EA, Lafferty DJR. 2022. Human-provisioned foods reduce gut microbiome diversity in American black bears (Ursus americanus). J Mammal 103:339–346.

Other interesting stories:

• 3D-printed electrode structures harvest electricity from bacterial photosynthesis
• Gut microbes are important for helping tadpoles survive in warmer conditions

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479 - Uncomplicated Critters Conquer Cancer

T. adhaerens
By Fortunato et al. 2021.
PLOS Biol e3001471
CC BY 4.0

This episode: Simple microscopic animals can survive extreme radiation by ejecting damaged cells that might otherwise become cancer!
Download Episode (7.3 MB, 9.2 minutes)

Show notes:
Microbe of the episode: Helleborus net necrosis virus

News item

Takeaways

Any multicellular organism with different types of cells needs some sort of cell regulation, to keep each cell type doing what it’s supposed to do for the good of the organism as a whole. We know what happens when this regulation fails and one type of cells starts multiplying out of control: cancer.

However, cancer has never yet been observed in certain organisms, including the simple microscopic animal Trichoplax adhaerens. In this study, these animals are exposed to large amounts of radiation and then observed over years to see if they can develop cancer or have interesting mechanisms of resisting it.

Journal Paper:
Fortunato A, Fleming A, Aktipis A, Maley CC. 2021. Upregulation of DNA repair genes and cell extrusion underpin the remarkable radiation resistance of Trichoplax adhaerens. PLOS Biol 19:e3001471.

Other interesting stories:

• Genes transferred from bacteria to algae helped land plants evolve

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478 - Babies Bear Bacterial Birthright

E. coli, a common gut microbe

This episode: How family members share gut microbes across multiple generations!
Download Episode (7.3 MB, 10.7 minutes)

Show notes:
Microbe of the episode: Dyozetapapillomavirus 1

Takeaways

Our gut’s microbial communities can greatly influence our health, for good or bad. The makeup of these communities can be influenced by many factors, including genetics, health status, diet, and other aspects of the environment we live in. We’ve learned a lot about this topic recently, but there’s a lot more we still don’t understand.

In this study, gut microbe samples from individuals spanning multiple generations in the same families were compared, to see how much influence family relationships and cohabitation could have on the gut communities. Both genetic relationship and living together had influences on which gut microbes different people shared.

Journal Paper:
Valles-Colomer M, Bacigalupe R, Vieira-Silva S, Suzuki S, Darzi Y, Tito RY, Yamada T, Segata N, Raes J, Falony G. 2022. Variation and transmission of the human gut microbiota across multiple familial generations. 1. Nat Microbiol 7:87–96.

Other interesting stories:

• Simple modification to interesting bacteria make them excrete nitrogen fertilizer
• Making carbon dioxide into useful chemicals with bacteria

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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)

News item

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

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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

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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

 

News item

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

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470 - Super Small Symbionts Soothe Symptoms

Tiny symbiont Saccharibacteria (yellow-green)
on host bacteria (red)
By Utter et al.,
CC BY-SA 4.0

This episode: Tiny bacteria that live on larger bacteria reduce the inflammation and gum disease the bigger microbes cause in the mouths of mice!

Download Episode (6.3 MB, 9.2 minutes)

Show notes:
Microbe of the episode: Actinomadura viridilutea

Takeaways

Even bacteria can be hosts to smaller symbionts living on them. Some kinds of these extremely tiny bacteria live in various parts of our bodies, and are sometimes associated with inflammation and the resulting disease. But being associated with something isn't necessarily the same as causing that thing.

In this study, tiny bacteria living on other bacteria in the mouths of mice were found to reduce the inflammation caused by their bacterial hosts, resulting in less gum disease and bone loss in the jaw. Even when the tiny bacteria were no longer present, their former bacterial hosts were still less disruptive to the mouse mouth.

Journal Paper:
Chipashvili O, Utter DR, Bedree JK, Ma Y, Schulte F, Mascarin G, Alayyoubi Y, Chouhan D, Hardt M, Bidlack F, Hasturk H, He X, McLean JS, Bor B. 2021. Episymbiotic Saccharibacteria suppresses gingival inflammation and bone loss in mice through host bacterial modulation. Cell Host Microbe 29:1649-1662.e7.

Other interesting stories:

• Anti-tumor bacteria: engineered E. coli colonizes tumors and attracts immune response
• Cats have skin bacteria that could inhibit drug resistant pathogens

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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

News item

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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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

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459 - Prokaryotes Provide Polyp Perserverance

Coral
By Brocken Inaglory
CC BY-SA 4.0

This episode: Transplanting microbes from some corals to others could help the corals survive high temperatures!

Download Episode (5.7 MB, 8.3 minutes)

Show notes:
Microbe of the episode: Streptomyces olivaceoviridis

News item

Takeaways

The ever-rising temperatures of our modern world are putting more and more stress on various ecosystems. This is true even on the ocean floor: record-high temperatures damage reefs by causing coral bleaching, in which corals lose their photosynthetic endosymbionts. If conditions do not improve, these corals eventually die.

Corals have microbial symbionts other than the phototrophs, also. We know from ourselves and from plants that microbes can have big effects on their hosts, so it seemed worth testing whether symbionts from more heat-resistant corals could transfer heat resistance to more vulnerable individuals. Recipients of this treatment did show enhanced heat resistance, but the microbial community composition did not always change after the treatment.

Journal Paper:
Doering T, Wall M, Putchim L, Rattanawongwan T, Schroeder R, Hentschel U, Roik A. 2021. Towards enhancing coral heat tolerance: a “microbiome transplantation” treatment using inoculations of homogenized coral tissues. Microbiome 9:102.

Other interesting stories:

• Tiny bacterium kills larger bacterium that makes troublesome foam

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455 - Marine Microbes Make Megapascal Management Molecule

Myroides profundi
By Qin et al. 2021,
Sci Adv 7:eabf9941
CC BY-NC 4.0

This episode, in honor of World Ocean Day: Bacteria that may move between high and low pressure areas in the ocean use a particular molecule to protect their cells from being crushed!

Download Episode (6.6 MB, 9.5 minutes)

Show notes:
Microbe of the episode: Rickettsia rickettsii

News item

Takeaways

Life in the ocean can have many challenges, depending on the organism and where it lives. Microbes can be found in almost every region, from the warmest to coldest, brightest to darkest, and shallowest to deepest. Sometimes microbes are carried from shallow to deep regions, where the weight of so much water causes immense pressure, which can inhibit cellular structural integrity and function. So life in the deep sea must have ways to deal with this pressure to survive. In this study, bacteria transform a fairly common chemical into a molecule that cushions and protects their cellular structures from the effects of high pressure, allowing them to survive lower down than they would otherwise.

Journal Paper:
Qin Q-L, Wang Z-B, Su H-N, Chen X-L, Miao J, Wang X-J, Li C-Y, Zhang X-Y, Li P-Y, Wang M, Fang J, Lidbury I, Zhang W, Zhang X-H, Yang G-P, Chen Y, Zhang Y-Z. 2021. Oxidation of trimethylamine to trimethylamine N -oxide facilitates high hydrostatic pressure tolerance in a generalist bacterial lineage. Sci Adv 7:eabf9941.

Other interesting stories:

• Engineering microbes to produce petroleum product precursor isoprene

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

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446 - Biofilm Benefits Bone Braces

Biofilm-coated implant
By Tan et al. 2020,
Sci Adv 6:eaba5723
CC BY-NC 4.0

This episode: The biofilm that probiotic bacteria can leave behind on a titanium implant seems to help it integrate better with the existing skeleton, with less inflammation and risk of infection!

Download Episode (5.5 MB, 7.9 minutes)

Show notes:
Microbe of the episode: Methylobacterium organophilum

News item

Takeaways

Skeletal implants make it a lot easier for many people to stay mobile as they age, but the surgical procedure of implanting is risky. Its invasive nature puts stress on the immune system, which puts stress on other systems, and the spread of antibiotic resistance is increasing the risk of a hard-to-treat infection.

In this study, probiotic bacteria grow in a biofilm on titanium implants before being inactivated, leaving only the biofilm behind on the implant. This biofilm-coated implant showed improved bone integration, antimicrobial resistance that was not toxic to the body's own tissues, and reduced inflammation when implanted into rats.

Journal Paper:
Tan L, Fu J, Feng F, Liu X, Cui Z, Li B, Han Y, Zheng Y, Yeung KWK, Li Z, Zhu S, Liang Y, Feng X, Wang X, Wu S. 2020. Engineered probiotics biofilm enhances osseointegration via immunoregulation and anti-infection. Sci Adv 6:eaba5723.

Other interesting stories:

• Certain gut microbes correlate with lower risk from norovirus (paper)
• Mixture of microbes similar to kombucha engineered to produce living functional materials

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

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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!

Download Episode (7.3 MB, 10.6 minutes)

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

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

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438 - Bacteria Bait Bug Babies

Drosophila fruit fly
By André Karwath
CC BY-SA 2.5

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.

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

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437 - Balmy Bacteria Build Bone

Porous interior of bone
By Daniel Ullrich Threedots
CC BY-SA 3.0

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

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

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435 - Invader Introducing Infrared Invokes Immunity

Mouse with darkened tumor
By Yi et al. 2020,
Sci Adv 6:eaba3546
CC BY-NC 4.0

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)

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

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