BacterioFiles 391 - Slime Stores Sodium Sensibility

Physarum polycephalum on a log

By frankenstoen - flickr, CC BY 2.5

This episode: Slime molds can learn to get used to salt and hold on to that memory even after a period of dormancy!

Download Episode (8.9 MB, 9.7 minutes)

Show notes:
Microbe of the episode: Nocardia transvalensis

News item

Takeaways
Slime mold Physarum polycephalum has many surprisingly intelligent abilities, despite being only a single cell. Studying how these abilities work in the cell can teach us new ways that life can do things. The ability of interest here is habituation, or learning not to avoid a chemical that seems unpleasant to the cell but is not necessarily harmful, especially with a food reward.

The slime mold can become habituated to salt, in this case, learning to tolerate it enough to pass through a gradient of increasing concentration to get to some food as quickly as it crosses the same distance with no salt present. The scientists here learned that the cell takes up sodium into itself as it habituates, and holds onto both sodium and its memory through a period of hibernation.

Journal Paper:
Boussard A., Delescluse J., Pérez-Escudero A., Dussutour A. 2019. Memory inception and preservation in slime moulds: the quest for a common mechanism. Phil Trans R Soc B 374:20180368.

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

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BacterioFiles 390 - Friendly Phages Find Foes

E. coli bacteria

This episode: Bacteria carry deadly phages and use them against rival strains!

Download Episode (9.4 MB, 10.2 minutes)

Show notes:
Microbe of the episode: Bifidobacterium bifidum

News item

Takeaways
Bacteria such as Escherichia coli live in environments such as the gut with many other types of microbes, and often develop communities of microbes cooperating and/or competing with each other for resources. But in order to cooperate or compete, bacteria must first be able to identify and discriminate between themselves and others. Sometimes microbes do this by exchanging membrane molecules, or secreting chemical signals that only partners can detect, or transferring plasmids or producing antimicrobial compounds that kill competitors.

In the current study, scientists discovered a strain of E. coli that carries around phages that help them distinguish other strains and compete with them. When this strain encounters another, the phages it carries attack and destroy cells of the other strain, while leaving the carrier strain mostly unharmed. This strategy is not without cost, though; the viral proteins take resources to produce, and when there's no competing strains around, the virus can attack its carrier to some extent.

Journal Paper:
Song S, Guo Y, Kim J-S, Wang X, Wood TK. 2019. Phages Mediate Bacterial Self-Recognition. Cell Reports 27:737-749.e4.

Other interesting stories:

• E. coli adjusts its swimming to get around obstacles

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

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BacterioFiles 389 - Prokaryotes Pacify Protein Problem

E. coli bacteria

This episode: Engineered bacteria could help people digest an essential nutrient when they can't digest it themselves!

Download Episode (8.5 MB, 9.3 minutes)

Show notes:
Microbe of the episode: Kadipiro virus

News item (paywall)

Science-Based Medicine blog article about phenylketonuria, Synlogic, and engineering bacteria to treat this disorder, with lots of good detail

Takeaways
Treating genetic disorders can be very difficult. Sometimes they can be managed, with lifestyle, diet, or medication, but cure has almost always been out of the picture. With a disorder such as phenylketonuria (PKU), for example, in which the body is unable to fully metabolize the amino acid phenylalanine, diet and medication may work to some extent.

In an effort to provide better options for PKU, scientists at Synlogic, Inc have created a strain of Escherichia coli that produces phenylalanine-degrading enzymes in the gut. The hope is that ingesting this bacterium could allow PKU patients to be less restrictive with their diet.

Journal Paper:
Isabella VM, Ha BN, Castillo MJ, Lubkowicz DJ, Rowe SE, Millet YA, Anderson CL, Li N, Fisher AB, West KA, Reeder PJ, Momin MM, Bergeron CG, Guilmain SE, Miller PF, Kurtz CB, Falb D. 2018. Development of a synthetic live bacterial therapeutic for the human metabolic disease phenylketonuria. Nat Biotechnol 36:857–864.

Other interesting stories:

• Probiotic molecule induces protection in mice against viral brain infection
• E. coli growing with artificially synthesized genome (Extra information)

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

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Skipping a week

Sorry, no episode this week, due to vacations and busy-ness.

BacterioFiles 388 - Floor Fungi Fracture Phthalates

This episode: Microbes in household dust help degrade potentially harmful plasticizer chemicals!

Thanks to Ashleigh Bope for her contribution!

Download Episode (6.7 MB, 7.3 minutes)

Show notes:
Microbe of the episode: Rosa rugosa leaf distortion virus

News item

Takeaways
Modern life and technology comes with modern challenges, including exposure to chemicals in building materials and such that humans didn't encounter much before the last few generations. Phthalate esters, found in PVC and other materials, can accumulate in homes and cause some problems, especially in children.

Modern life is also new to microbes, but they are very adaptable and versatile. In this study, microbes in household dust show some ability to break down the phthalates over time. Whether this activity is significant and beneficial to residents remains to be discovered.

Journal Paper:
Bope A, Haines SR, Hegarty B, Weschler CJ, Peccia J, Dannemiller KC. Degradation of phthalate esters in floor dust at elevated relative humidity. Environ Sci: Processes Impacts.

Other interesting stories:

• Native fungi tag team to kill invasive insect pest (paper)

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

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BacterioFiles 387 - Carbonate Creators Combat Cracking

Sporosarcina pasteurii

By Ghosh et al. 2019. 

PLoS ONE 14(1):e0210339 

CC BY 4.0

This episode: Bacteria strengthen concrete while helping to prevent damage from road salts!

Download Episode (6.8 MB, 7.4 minutes)

Show notes:
Microbe of the episode: Azospirillum brasilense

News item

Takeaways
Winter is a bad time for concrete outside. Water seeps into cracks and freezes, causing bigger cracks that widen into potholes. Even the road salts used to keep water from freezing can react with compounds in the cement to break down the structure of the concrete.

This study looks to bacteria for a solution for protecting concrete from these reactions. Sporosarcina pasteurii, given the right nutrients, can take the harmful salt compounds and turn them into minerals that strengthen the concrete instead of weakening it.

Journal Paper:
Ksara M, Newkirk R, Langroodi SK, Althoey F, Sales CM, Schauer CL, Farnam Y. 2019. Microbial damage mitigation strategy in cementitious materials exposed to calcium chloride. Construction and Building Materials 195:1–9.

Other interesting stories:

• Developing way for bacteria to make mother-of-pearl, a tough and useful material

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

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BacterioFiles 386 - Cupola Contaminant Cleaners

Pisa cupola painting
By JoJan, CC BY-SA 3.0

This episode: Bacteria help gently clean residue off artworks painted on stone!

Download Episode (5.6 MB, 6.1 minutes)

Show notes:
Microbe of the episode: Cellulophaga virus Cba171

Takeaways
More and more cleaning products these days contain an ingredient called "enzymes." These are proteins that break down contaminants biologically instead of just removing them chemically, in a targeted manner.

In a similar approach, this study explores applying bacteria directly to classic artwork painted directly on stone, to clean up residues on the surface. These bacteria can produce enzymes on site and degrade the contaminants while leaving the underlying paint intact.

Journal Paper:
Ranalli G, Zanardini E, Rampazzi L, Corti C, Andreotti A, Colombini MP, Bosch‐Roig P, Lustrato G, Giantomassi C, Zari D, Virilli P. 2019. Onsite advanced biocleaning system on historical wall paintings using new agar-gauze bacteria gel. J Appl Microbiol 126:1785–1796.

Other interesting stories:

• Mouth bacteria prevent gum disease by interfering with activity of other bacteria (paper)
• Despite identical genetics, individual bacteria can behave differently through random variation

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

Subscribe: Apple Podcasts, RSS, Google Play. Support the show at Patreon, or check out the show at Twitter or Facebook.