Monday, June 21, 2021

456 - Invader Induces Increased Immensity

Sulfolobus infected
with STSV1
By Xiangyux
From Wikipedia
This episode: A virus of archaea stops cells from dividing, so they just keep getting bigger and releasing more viruses!

Download Episode (6.9 MB, 10.1 minutes)

Show notes:
Microbe of the episode: Streptomyces caelestis

Takeaways
Viruses affect their hosts many different ways: instant hostile takeover of cellular machinery, lurking unseen in the genome for generations, inducing reduced cell division or excessive cell division, and more. Archaeal viruses are relatively unknown in their genetic abilities and lifestyles, but we do know that they tend not to destroy their hosts through explosive viral reproduction, and that some archaea have eukaryote-like cell cycle phases.

In this study, some viruses infecting a thermophilic archaeon interrupt its cycle in the growth phase, so hosts expand in size up to around 17 times normal, continuously releasing new viruses over time. Eventually some archaea in the population gain resistance to the viruses via their CRISPR/Cas systems, and normal-sized cells dominate the population again.

Journal Paper:
Liu J, Cvirkaite-Krupovic V, Baquero DP, Yang Y, Zhang Q, Shen Y, Krupovic M. 2021. Virus-induced cell gigantism and asymmetric cell division in archaea. Proc Natl Acad Sci 118:e2022578118.

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Monday, June 7, 2021

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!

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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.

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Monday, May 31, 2021

454 - Hitchhiking Horticultural Helpers

Bacteria carrying spores
By Muok et al. 2021
ISME J, CC BY 4.0
This episode: Spores of some bacteria latch onto the tails of other bacteria and ride along as they move around in the soil!

Download Episode (5.5 MB, 8.0 minutes)

Show notes:
Microbe of the episode: Bohle iridovirus

News item

Takeaways
The soil is a complex environment, and microbes that live in soil need complex lifestyles to thrive. There are many examples of cooperation, competition, and other adaptations to highly varied situations.

In this study, bacteria that grow like filamentous fungi don't have the mechanisms to move autonomously, but their spores can hitch rides on other kinds of bacteria that swarm through the soil using their propeller-like tails called flagella to push themselves toward the plant roots they prefer to grow near.

Journal Paper:
Muok AR, Claessen D, Briegel A. 2021. Microbial hitchhiking: how Streptomyces spores are transported by motile soil bacteria. ISME J.

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Monday, May 24, 2021

453 - Phenazine Faciliates Phosphorus Feeding

Pseudomonas aeruginosa
By Y_tambe, CC BY-SA 3.0
This episode: Some bacteria produce antibiotics that can also help them gather more nutrients!

Download Episode (5.0 MB, 7.3 minutes)

Show notes:
Microbe of the episode: Diadromus pulchellus toursvirus

News item 1

Takeaways
Antibiotics have saved a lot of lives since they were discovered and used to treat many previously untreatable bacterial infections. But bacteria themselves have been making antibiotics much longer than we have, to help compete in their environment. However, sometimes these compounds are not produced in large enough concentrations to act as antibiotics, killing or inhibiting rival bacteria. Why waste energy on this sublethal production? Are there other functions these molecules can perform?

In this study, bacteria produce an antibiotic called phenazine that can damage cell components by redox reactions, transferring electrons. But it can also help liberate the essential nutrient phosphorus from being bound to insoluble particles, allowing the bacteria to grow better even in the absence of competitors.

Journal Paper:
McRose DL, Newman DK. 2021. Redox-active antibiotics enhance phosphorus bioavailability. Science 371:1033–1037.
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Monday, May 3, 2021

452 - Prokaryotic Partner Powers Protist

Anaerobic ciliate
By Graf et al. 2021
Nature, CC BY 4.0
This episode: Single-celled eukaryotes can thrive without oxygen with the help of bacterial endosymbionts that respire nitrate the way our mitochondria respire oxygen!

Thanks to Jon Graf for his contribution!

Download Episode (12.4 MB, 18.1 minutes)

Show notes:
Microbe of the episode: Brenneria salicis

News item 1 / News item 2

Takeaways
The combination of a bacterium and other microbe into the first eukaryote was a big advance in evolutionary history; it made possible the huge variety of different body shapes and sizes we see today. This is thanks to the bacterial endosymbiont, the mitochondrion, taking on specialized metabolic tasks for the cell.

We already knew about endosymbionts that help with oxygen respiration, with photosynthesis (chloroplasts), and with amino acid synthesis (certain endosymbionts in insects). But bacteria have other metabolic abilities that are very useful in certain conditions; do these bacteria ever team up with other organisms? The answer is yes! In this study, ciliates were discovered at the bottom of a lake in oxygen-free waters. These protists have an bacterial endosymbiont that helps them respire, not oxygen, but nitrate instead, generating more energy than most anaerobic ciliates.

Journal Paper:
Graf JS, Schorn S, Kitzinger K, Ahmerkamp S, Woehle C, Huettel B, Schubert CJ, Kuypers MMM, Milucka J. 2021. Anaerobic endosymbiont generates energy for ciliate host by denitrification. Nature.

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Monday, April 19, 2021

451 - Phototrophs Fancy Floating Feasts

Prasinophyte algae
By Bock et al. 2021, ISME J
CC BY 4.0
This episode: Despite being photosynthetic, some kinds of algae engage in predatory behavior, hunting and consuming live bacteria!

Thanks to Nicholas Bock for his contribution!

Download Episode (4.9 MB, 7.1 minutes)

Show notes:
Microbe of the episode: Paramecium bursaria Chlorella virus 1

News item

Takeaways
Although most of them are microscopic, algae perform a significant portion of the photosynthesis on the planet, because there are so many of them. But even though photosynthesis seems like a reliable way of acquiring energy, there are conditions under which even algae benefit from gathering energy and nutrients from other organisms. This is called phagomixotrophy, when algae hunt and consume bacteria.

In this study, scientists developed fluorescence methods for detecting and studying this predation in a group of algal phytoplankton that's not well-studied, prasinophytes. They found that all five species they looked at engaged in bacterivory under nutrient-depleted conditions, and that they preferred live bacteria to killed ones.

Journal Paper:
Bock NA, Charvet S, Burns J, Gyaltshen Y, Rozenberg A, Duhamel S, Kim E. 2021. Experimental identification and in silico prediction of bacterivory in green algae. ISME J.

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Monday, April 5, 2021

450 - Subterranean Spotlights Support Cyanobacteria

Carlsbad Caverns
By Eric Guinther, Marshman
CC BY-SA 3.0
This episode: Lighting in caves open to tourists supports the growth of unwanted photosynthetic bacteria!

Thanks to Zoƫ Havlena for her contribution!

Download Episode (6.6 MB, 9.5 minutes)

Show notes:
Microbe of the episode: Dill cryptic virus 2

Takeaways
Caves can contain amazing beauty, intricate geological formations formed by minerals, water, and time. Some, such as Carlsbad Caverns in New Mexico, have been fitted with instruments to allow tourists to pass through and see the wonders within; definitely a worthwhile experience.

Caves also have their own natural microbiota that can live within them, in the dark, somewhat cold, and nutrient-poor conditions. But with the lighting installed to allow tourism, photosynthetic microbes have been able to take hold in the communities of these show caves. These microbes can outcompete the natural microbes, and can cause discoloration and unwanted growths on cave formations. They are difficult to remove without much effort and the risk of damaging the cave formations themselves. 

This study looked at the effects of the color of lighting in the caves, as well as other factors, on the growth of these so-called "lampenflora." It supports new efforts and methods to control the issue.

Journal Paper:
Havlena Z, Kieft TL, Veni G, Horrocks RD, Jones DS. 2021. Lighting Effects on the Development and Diversity of Photosynthetic Biofilm Communities in Carlsbad Cavern, New Mexico. Appl Environ Microbiol 87.

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