431 - Conductive Cables Control Carbon

Cable bacteria around
plant roots
From Scholz et al. 2020
Nat Commun 11:1878

This episode: Cable bacteria around rice roots transport electrons and help prevent formation of methane!

Thanks to Vincent Scholz for his contribution!  
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Show notes:
Microbe of the episode: Vibrio alginolyticus

News item

Takeaways

Transforming other things into methane is a great way to make a living for some kinds of microbes. These tend to live under still water, like in rice fields or wetlands, or in the guts of cattle. And while this methane could be useful as natural gas if collected, it's a much more potent greenhouse gas than carbon dioxide when released into the atmosphere.

In this study, cable bacteria were inoculated into rice pots in the lab. Cable bacteria transfer electrons from deeper down in the ground up to the surface to generate energy, and in the process generate sulfate. This sulfate allows other microbes to outcompete the methane producers, reducing the amount of methane produced from rice cultivation in the lab. This may be helpful to reduce greenhouse gas emissions from rice agriculture.

Journal Paper:
Scholz VV, Meckenstock RU, Nielsen LP, Risgaard-Petersen N. 2020. Cable bacteria reduce methane emissions from rice-vegetated soils. 1. Nat Commun 11:1878.

Other interesting stories:

• Viruses in fecal transplants, not just bacteria, may be useful for health
• Superworms and their symbiont bacteria can degrade styrofoam

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

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430 - Dextrose Deposits Delay Dormancy

E. coli

This episode: Bacteria that can store sugar as glycogen have multiple advantages when food is only available sporadically!
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Show notes:
Microbe of the episode: Carnivore bocaparvovirus 3

Takeaways

Almost all habitats experience some sort of change and fluctuation; very few are totally stable, depending on the timeframe. So strategies to change and adapt with changing conditions can greatly help an organism thrive. For example, methods of storing energy are helpful when food is only available sporadically.

Some bacteria, like humans, can store sugar in a polymer called glycogen, which can be quickly produced when food is abundant and quickly broken down to ease a transition to fasting. In this study, bacteria that could produce and use glycogen were able to stay active longer and grow better in the face of intermittent starvation. They were even better able to acquire new food when more became available.

Journal Paper:
Sekar K, Linker SM, Nguyen J, Grünhagen A, Stocker R, Sauer U. 2020. Bacterial Glycogen Provides Short-Term Benefits in Changing Environments. Appl Environ Microbiol 86.

Other interesting stories:

• Bacteria can grow so well in spent nuclear fuel ponds, they make the water cloudy
• Certain probiotic bacteria might be able to degrade gluten and protect people with celiac

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

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429 - Springtails Smell, Spread Streptomyces

Springtail Folsomia candida
By Andy Murray
CC BY-SA 2.0

This episode: Bacteria in soil produce smells to attract arthropods that eat them but also spread their spores!

Download Episode (6.2 MB, 9.0 minutes)

Show notes:
Microbe of the episode: Blotched snakehead virus

News item

Takeaways

Soil, especially after a rain, often has a characteristic "earthy" smell. This soil smell is actually the result of certain bacteria producing a volatile chemical called geosmin. Many geosmin producers are in the Streptomyces genus, which produces a large variety of interesting chemicals, but geosmin is one of the few that is nearly universal in the genus.

This study found that insect-like arthropods called springtails are attracted to geosmin. These animals usually feed on fungi, but they will also eat bacteria when available. Despite this result, the bacteria continue to produce the chemical, which is linked to their sporulation cycle. The study found that springtails carry intact bacterial spores to new places stuck to the insides and outsides of the animal, and this enhances the dispersal ability of the bacteria.

Journal Paper:
Becher PG, Verschut V, Bibb MJ, Bush MJ, Molnár BP, Barane E, Al-Bassam MM, Chandra G, Song L, Challis GL, Buttner MJ, Flärdh K. 2020. Developmentally regulated volatiles geosmin and 2-methylisoborneol attract a soil arthropod to Streptomyces bacteria promoting spore dispersal. 6. Nat Microbiol 5:821–829.

Other interesting stories:

• Silicon nanowires help bacteria harvest light to fix carbon dioxide
• Bacterium produces membrane balls containing enzymes to help digest lignin

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

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428 - Microbes May Manage Mysteries

This episode: The skin microbes that people leave behind may be used to identify them, even after other people have touched the same surface!


Download Episode (5.4 MB, 7.9 minutes)

Show notes:
Microbe of the episode: Actinobacillus lignieresii

Takeaways

The microbial communities in and on our bodies are highly complex and highly varied between people; this complexity has raised the question of whether the microbes that people transfer onto things they touch could be used in forensics, to track their movement and activity, like fingerprints or DNA evidence. One difficulty with this approach is that microbe communities are constantly changing as conditions change or other microbes are introduced.

This study simulated such microbial tracking in a couple of scenarios, such as touching door handles in an office building and touching various surfaces in a home in a mock burglary. Tracking a person on door handles worked fairly well for up to an hour after the contact, even if other people had also touched the same door handles. However, the accuracy of identifying the "burglar" in a home was not very high, but modifying the analysis from looking at the community as a whole to only rare microbes relatively unique to an individual improved the results.

Journal Paper:
Hampton-Marcell JT, Larsen P, Anton T, Cralle L, Sangwan N, Lax S, Gottel N, Salas-Garcia M, Young C, Duncan G, Lopez JV, Gilbert JA. 2020. Detecting personal microbiota signatures at artificial crime scenes. Forensic Sci Int 313:110351.

Other interesting stories:

• Using slime molds to model the gravity-based web of gas and dark matter between galaxies
• Using bacteria to produce antibody-like molecules (paper)

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

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427 - Simple Cells Stay Strong

Fluorescent SimCells
By Fan et al. 2020,
PNAS 117(12):6752
CC BY 4.0

This episode: Bacterial cells with their genomes removed can still be active and useful!


Download Episode (10.2 MB, 14.9 minutes)

Show notes:
Microbe of the episode: Rosavirus A

Takeaways

Microbes have amazing biochemical transformation abilities, creating and breaking down many compounds and proteins. This makes them great candidates for many purposes, in medicine, industry, and environmental remediation. In some of these purposes, though, there are risks associated with adding foreign microbes, especially engineered ones, that can replicate themselves and possibly persist, into new places.

To avoid this risk, this study turns intact bacteria into SimCells, simplified entities with most of their genetic material removed, leaving only the proteins and other components and just enough DNA to accomplish desired tasks. These SimCells were able to continue performing tasks for around 10 days before running out of the cellular resources needed to keep going. One of these tasks was producing a compound that damaged cancer cells in a dish but left non-cancerous cells unharmed.

Journal Paper:
Fan C, Davison PA, Habgood R, Zeng H, Decker CM, Salazar MG, Lueangwattanapong K, Townley HE, Yang A, Thompson IP, Ye H, Cui Z, Schmidt F, Hunter CN, Huang WE. 2020. Chromosome-free bacterial cells are safe and programmable platforms for synthetic biology. Proc Natl Acad Sci 117:6752–6761.

Other interesting stories:

• Biofuel-producing bacteria can generate electricity at the same time (paper)
• Using dried microbial biomass as fertilizer works pretty well (paper)

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.