491 - Less Liquid Lands Losing Lichens

Lichens on rock By Jesse Noar CC BY 4.0

This episode: Trends of declining lichen populations and biocrust cover overall match trends of increasing temperatures in Colorado dryland!
Download Episode (6.4 MB, 9.3 minutes)

Show notes:

Microbe of the episode: Cherry chlorotic rusty spot associated partitivirus

Takeaways:

Global climate change is affecting almost every natural system on the planet, in predictable and also sometimes unexpected, complex ways. Microbes perform key roles in many different ecosystems, providing and recycling important nutrients and even macroscopic structure. One example of this is biocrusts in dryland environments, such as areas in the western US with low annual rainfall. Microbes other organisms form a stable surface binding soil and sand particles together, helping to retain moisture and prevent erosion and transformation of land into desert.

In this study of a Colorado park over more than 20 years, important species of symbiotic fungi and photosynthetic microbes in the form of lichens have declined significantly. The land is mostly untroubled by grazing or human activity, but changes in climate and moisture and the presence of invasive plants could affect lichens. However, the temperature increase over the decades showed the best correlation with the lichen decline. The loss of these species could lead to nutrient shortages in the long term for these communities.

Journal Paper:

Finger-Higgens R, Duniway MC, Fick S, Geiger EL, Hoover DL, Pfennigwerth AA, Van Scoyoc MW, Belnap J. 2022. Decline in biological soil crust N-fixing lichens linked to increasing summertime temperatures. Proc Natl Acad Sci USA 119:e2120975119.

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485 - Small Cell Sculpts Sticky Snot Sphere

Mucosphere with captured prey
Larsson et al. 2022.
Nat Commun 13:1301
CC BY 4.0

This episode: A marine protist predator traps prey microbes in an attractive bubble of mucus, eats what it wants, and lets the rest sink, possibly sequestering significant amounts of carbon!
Download Episode (7.8 MB, 11.4 minutes)

Show notes:
Microbe of the episode: Bat associated cyclovirus 1

News item

Takeaways

The oceans have a lot of unique, unexplored life in them. This is true on a macro level but even more on a microscopic level, with many different kinds of microbes of various groups with fascinating life strategies. And despite being microscopic, with enough of them around, they can affect the whole planet's climate in significant ways.

In this study, one protist species gets most of its nutrients from photosynthesis, but what it can't get from the sun, it takes from prey microbes by force. To catch its prey, it creates an intricate bubble of mucus called a mucosphere, and waits for other microbes to swim into it, thinking it is food, and get stuck. Then the predator chooses the prey cell it wants and abandons the rest, letting them sink to the ocean floor and locking away the carbon they contain in the process.

Journal Paper:
Larsson ME, Bramucci AR, Collins S, Hallegraeff G, Kahlke T, Raina J-B, Seymour JR, Doblin MA. 2022. Mucospheres produced by a mixotrophic protist impact ocean carbon cycling. Nat Commun 13:1301.

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462 - Super Ciliate Symbiont Set

Pseudoblepharisma tenue
By Muñoz-Gómez et al, 2021,
Sci Adv 7:eabg4102, CC BY 4.0

This episode: A eukaryote has symbionts living in it: green algae and also purple bacteria, a combo never seen before!

Download Episode (6.1 MB, 8.8 minutes)

Show notes:
Microbe of the episode: Staphylococcus virus phiETA

News item

Takeaways

Having bacteria as endosymbionts is fairly common in life on Earth: almost all eukaryotes have them in the form of mitochondria and sometimes chloroplasts. These former bacteria somehow got inside the ancestral eukaryote, either as parasites or as prey, and ended up as integral parts of their host's metabolic functions. Some organisms, especially insects, obtained bacterial endosymbionts more recently, that help them balance their metabolic needs when living on limited diets.

Algae have been known to be endosymbionts also, performing photosynthesis for their host. But in this study, a ciliate with both algae and purple photosynthetic bacteria as endosymbionts was discovered. Purple bacteria as symbionts is rare, and this combination has not been observed before. Interestingly, though algae produce oxygen through their photosynthesis, the ciliate prefers living in low-oxygen sediment at the bottom of a pond. The symbionts and their host seem to adjust their metabolisms as needed depending on the needs at the time; they may each perform photosynthesis, fermentation, or respiration if light, organic carbon, or oxygen are available.

Journal Paper:
Muñoz-Gómez SA, Kreutz M, Hess S. 2021. A microbial eukaryote with a unique combination of purple bacteria and green algae as endosymbionts. Sci Adv 7:eabg4102.

Other interesting stories:

• Oxygen-producing microbes could help treat acute strokes

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460 - Prokaryote Publicity Prevents Protist Processes

Emiliania huxleyi
By Alison R. Taylor
UNC Wilmington Microscopy
PLoS Biology, June 2011 Cover
CC BY 2.5

This episode: A bacterial communication signal makes algae stop growing, which helps them survive virus attacks!

Download Episode (5.3 MB, 7.7 minutes)

Show notes:
Microbe of the episode: Veillonella parvula

Takeaways

Many interesting interactions between microbes take place in the ocean. As single-celled organisms lacking complex sensory organs, many such interactions and communications are mediated by chemical signals. Some bacteria, for example, each produce small amounts of certain chemicals and release them into the environment. When the concentration of the chemical signal builds up to a certain point, the bacteria change their behavior to take advantage of their high numbers that must be present to produce so much of the signal. This process is called quorum sensing.

Some of these chemical signals can affect the behavior of organisms other than bacteria also. In this study, a common marine algal species was found to stop growing in response to a certain bacterial signal. This chemical inhibits an enzyme required for the algae to produce nucleotides to replicate their genomes. As a result, the algae are able to resist destruction by a virus that would otherwise decimate their populations.

Journal Paper:
Pollara SB, Becker JW, Nunn BL, Boiteau R, Repeta D, Mudge MC, Downing G, Chase D, Harvey EL, Whalen KE. 2021. Bacterial Quorum-Sensing Signal Arrests Phytoplankton Cell Division and Impacts Virus-Induced Mortality. mSphere 6:e00009-21.

Other interesting stories:

• Comparing ancient gut microbes from fecal fossils to modern gut communities / also this one

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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.

Other interesting stories:

• Fecal microbe transplant seems to help mice recover from spinal cord injury (paper)

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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 Zoë 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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449 - Paralyzed Poisons Push Power

Hydrothermal vent

This episode: Deep-sea bacteria can detoxify cadmium and convert it to light-capturing particles!

Download Episode (5.8 MB, 8.4 minutes)

Show notes:
Microbe of the episode: Arthrobacter virus Sonny

Takeaways

Hydrothermal vents can have thriving communities, despite being too deep for much light to penetrate. Microbes can derive energy from chemicals coming out of the vent, and form the foundation of the food chain. But toxic heavy metals also come out of the vent, including lead, mercury, and cadmium.

The microbes in this study were found to be resistant to cadmium, which they can detoxify by combining it with the sulfur found in the amino acid cysteine. This forms cadmium-sulfur nanoparticles, which can function as light-absorbing semiconductors, allowing the bacteria to harvest light energy.

Journal Paper:
Ma N, Sha Z, Sun C. 2021. Formation of cadmium sulfide nanoparticles mediates cadmium resistance and light utilization of the deep-sea bacterium Idiomarina sp. OT37-5b. Environ Microbiol 23:934–948.

Other interesting stories:

• Different fungi behave differently in growing through a tiny maze
• Bacteriophages could be used as disinfectants in some situations (paper)

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442 - Fossil Phototroph Phagocytosis

Fossilized coccolithophores
By Gibbs et al. 2020
Sci Adv 6:eabc9123
CC BY-NC 4.0

This episode: Algae surviving impact that killed the dinosaurs seem to have consumed other organisms to make it through the dark times!

Download Episode (7.1 MB, 10.3 minutes)

Show notes:
Microbe of the episode: Chaetoceros tenuissimus RNA virus 01

News item

Takeaways

Being able to look through time and learn about what might have happened to creatures throughout Earth's history is what makes paleontology great. Everyone knows about dinosaurs and what happened to them at the end of the Cretaceous period thanks to science. But what we can learn is not limited just to large organisms; there are ways to learn about microorganisms of the past as well, including by looking at fossils!

In this study, fossils of hard-shelled algae from around the end of the dinosaurs show that many of these microbes in the oceans went extinct at the same time due to the massive space impact. Debris blocked out sunlight for years, making it difficult for photosynthetic organisms to survive. So some of these algae appear to have survived by preying on smaller organisms, pulling them in through a hole in their shell.

Journal Paper:
Gibbs SJ, Bown PR, Ward BA, Alvarez SA, Kim H, Archontikis OA, Sauterey B, Poulton AJ, Wilson J, Ridgwell A. 2020. Algal plankton turn to hunting to survive and recover from end-Cretaceous impact darkness. Sci Adv 6:eabc9123.
Other interesting stories:

• Phages could help treat diabetic wound infections without harming microbiota (paper)

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422 - Frigid Phototrophs Fuel Fords

Algae growing in 20-liter bioreactor

Kim et. al, 2020. CC BY 4.0

This episode: Producing both biodiesel and bioethanol fuels from cold-loving Arctic algae!


Download Episode (8.7 MB, 12.6 minutes)

Show notes:
Microbe of the episode: Royal Farm virus

Takeaways

Renewable fuels such as biofuels can allow existing infrastructure and vehicles to continue to operate in a more sustainable manner, which could reduce the cost and impact of switching to new/different systems of transportation like electricity. Economically competitive methods of producing biofuels are still being explored and developed.

In this study, Arctic algae are grown in cold temperatures using only light, carbon dioxide, and a few minerals, and then broken down to produce biodiesel and bioethanol, which can be used as fuel in many different internal combustion engines. The amounts produced are comparable to other algae-based systems being researched, and use of the cold-loving organisms could reduce the cost of production in colder latitudes and seasons.

Journal Paper:
Kim EJ, Kim S, Choi H-G, Han SJ. 2020. Co-production of biodiesel and bioethanol using psychrophilic microalga Chlamydomonas sp. KNM0029C isolated from Arctic sea ice. Biotechnol Biofuel 13:20.

Other interesting stories:

• Certain foods could activate or inhibit bacteriophages and modulate the gut microbiota
• Some antibiotic-producing bacterial colonies have specialized members that do all the antibiotic production

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BacterioFiles 416 - Oxygen Or Other Oxidizes Iron?

Chlorobium phaeoferrooxidans

By Thompson et al, 2019.
Sci Adv 5:eaav2869.
CC BY-NC 4.0

This episode: Earth's iron deposits could have been created by anaerobic light-harvesting microbes instead of those that make oxygen!

Download Episode (9.3 MB, 13.5 minutes)

Show notes:
Microbe of the episode: Streptomyces avidinii

News item

Takeaways
In the ancient earth, the sun was dimmer, the world was colder, and oxygen was rare because photosynthesis had not yet evolved. Without oxygen to oxidize it, iron remained in its soluble, more accessible form, and many organisms took advantage of it for anaerobic metabolism.

But was it photosynthesis and the oxygen it created that transformed most of the planet's iron into its insoluble form, creating large iron deposits in the ground? This study explores the possibility that it was another form of light-harvesting metabolism, called photoferrotrophy, that uses light and the transformation of iron to generate energy. This hypothesis is found to be consistent with the evidence we have about what the early earth was like.

Journal Paper:
Thompson KJ, Kenward PA, Bauer KW, Warchola T, Gauger T, Martinez R, Simister RL, Michiels CC, Llirós M, Reinhard CT, Kappler A, Konhauser KO, Crowe SA. 2019. Photoferrotrophy, deposition of banded iron formations, and methane production in Archean oceans. Sci Adv 5:eaav2869.

Other interesting stories:

• Gut microbes help whales digest tricky fats in their diet
• Bacteria deliver antibiotic to competitors using capsules made of its own membrane (paper)

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BacterioFiles 415 - Global Glomus Growth Guesses

How mycorrhizal fungi work

By Nefronus, CC BY-SA 4.0

This episode: A global estimate of plants and their root fungi shows how agriculture may have greatly affected soil carbon storage over time!

Download Episode (5.7 MB, 8.3 minutes)

Show notes:
Microbe of the episode: Rhizobium virus RHEph4

News item

Takeaways
Even small organisms can have a big effect on the climate of the planet if there are enough of them. This includes trees, which are small relative to the planet, and also includes the fungi that attach to the roots of trees and other plants. These mycorrhizal fungi thread subtly through the soil, some occasionally popping up mushrooms, and transfer valuable nutrients they gather to the trees in exchange for carbon fixed from the air.

Knowing how big an effect a given kind of organism has requires knowing how much of it is around. This study collates data from various surveys of global plant populations and the fungi that interact with their roots, to estimate a global picture of the fungi below our feet. It estimates that a kind of fungus that stores more carbon in the soil may have been replaced in many areas with fungi that store less, or no fungi at all, due to the transformation of land from wild areas to farmland.

Journal Paper:
Soudzilovskaia NA, van Bodegom PM, Terrer C, Zelfde M van’t, McCallum I, Luke McCormack M, Fisher JB, Brundrett MC, de Sá NC, Tedersoo L. 2019. Global mycorrhizal plant distribution linked to terrestrial carbon stocks. Nat Commun 10:1–10.

Other interesting stories:

• Phages bind to fish mucosal surfaces and protect from infection
• Examining how archaea affect meteorites

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BacterioFiles 414 - Producing Proton Power Perpetually

Microalgae Chlamydomonas reinhardtii

This episode: Microalgae can produce hydrogen, but other metabolic pathways take priority, except when special engineered hydrogenase enzymes can overcome this limitation!

Download Episode (8.4 MB, 12.2 minutes)

Show notes:
Microbe of the episode: Alphapapillomavirus 11

Takeaways
There are many options being explored as ways to replace fossil fuels. Electricity and batteries are good, but they have their limitations, especially for long-distance high-energy travel such as airplanes. Hydrogen is one good option: high energy density, clean-burning, simple to produce. Microbes can produce hydrogen through various metabolic pathways, including fermentation, nitrogen fixation byproduct, and photosynthesis. However, competing metabolic pathways make microbial hydrogen production less efficient.

In this study, scientists engineer a hydrogenase enzyme for hydrogen production in microalgae that can compete better with carbon fixation as a destination for the electrons and protons that hydrogen production requires. This engineered enzyme allowed the algae to produce hydrogen continuously, even during photosynthesis.

Journal Paper:
Ben-Zvi O, Dafni E, Feldman Y, Yacoby I. 2019. Re-routing photosynthetic energy for continuous hydrogen production in vivo. Biotechnol Biofuels 12:266.

Other interesting stories:

• Plants use arsenic-dumping genes from bacteria to get essential nutrients
• Another study engineering better viruses for phage therapy

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

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BacterioFiles 412 - Carbon Concentration Complicates Crop Cooperation

Wheat plants
By Bluemoose, CC BY-SA 3.0

This episode: Looking at the effects of almost doubling CO₂ concentrations on the interaction between wheat varieties and beneficial fungi!

Download Episode (8.1 MB, 11.8 minutes)

Show notes:
Microbe of the episode: Lato River virus

News item

Takeaways
As the world's population grows, feeding everyone will grow more challenging. Advances in technology in the past have made today's population possible, but future advances may be needed, especially in the face of an increasing concentration of carbon dioxide in the atmosphere.

Soil microbes that partner with crop plants for the benefit of each may be part of the solution. One option to explore is a group called mycorrhizal fungi, which associate with plant roots to extend their nutrient-gathering ability, in exchange for carbon compounds produced by photosynthesis. This study examined the influence of increased carbon dioxide in the atmosphere on the interaction of several varieties of wheat with these fungi.

Journal Paper:
Thirkell TJ, Pastok D, Field KJ. Carbon for nutrient exchange between arbuscular mycorrhizal fungi and wheat varies according to cultivar and changes in atmospheric carbon dioxide concentration. Glob Change Biol.

Other interesting stories:

• Microbes could make paper whitening more environmentally friendly (paper)
• Compound from rotifers could prevent transmission of eukaryotic parasite

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

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BacterioFiles 408 - Currents Carry Cloud Creators

Snowflake
By Alexey Kljatov, CC BY-SA 4.0

This episode: Ocean bacteria brought up from the sea floor into the air can help create clouds!

Download Episode (6.1 MB, 8.9 minutes)

Show notes:
Microbe of the episode: Streptomyces thermodiastaticus

News item

Takeaways
The ocean is an important player affecting the climate of the planet, in many ways. Its effects on clouds influence the amount of solar radiation reflected back into space or trapped as heat, and microbes play a role in this effect. Certain microbes make particles that form the nucleus of water droplets or ice crystals that make up clouds, and other microbes can perform this nucleation themselves.

In this study, an unusual combination of a phytoplankton bloom and strong winds and currents, all in the right places, led to a large number of ice-nucleating bacteria being fed and then brought up from the sea floor and launched into the air, possibly affecting weather patterns in the Arctic.

Journal Paper:
Creamean JM, Cross JN, Pickart R, McRaven L, Lin P, Pacini A, Hanlon R, Schmale DG, Ceniceros J, Aydell T, Colombi N, Bolger E, DeMott PJ. 2019. Ice Nucleating Particles Carried From Below a Phytoplankton Bloom to the Arctic Atmosphere. Geophys Res Lett 46:8572–8581.

Other interesting stories:

• Bacterial immune system (CRISPR/Cas) could save bananas from fungus that wipes them out
• Potentially useful antibiotic produced by gut microbe (paper)

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

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BacterioFiles 407 - Fungus Facilitates Phototroph Feeding

Various Phomopsis fungi

Probably the last episode of the year. See you in the next!

This episode: Fungus living inside plants helps them form partnerships with nitrogen-fixing bacteria!

Download Episode (5.9 MB, 8.5 minutes)

Show notes:
Microbe of the episode: Prevotella intermedia

Takeaways
Plants are very good at acquiring carbon, but they can often use some help with other nutrients. Many form partnerships with microbes such as nitrogen-fixing bacteria or mycorrhizal fungi that can help gather nutrients from the soil better than the plants' own roots.

In this study, legume plants could form a partnership with nitrogen-fixing bacteria in its roots, but a fungus living inside the plant could enhance this partnership even more, increasing the amount of nitrogen acquired and influencing the community of microbes around the plant roots in ways favorable to all partners.

Journal Paper:
Xie X-G, Zhang F-M, Yang T, Chen Y, Li X-G, Dai C-C. 2019. Endophytic Fungus Drives Nodulation and N₂ Fixation Attributable to Specific Root Exudates. mBio 10:e00728-19, /mbio/10/4/mBio.00728-19.atom.

Other interesting stories:

• Diet could affect antibiotic impact on the gut microbiome
• Feeding gut microbes particular preferred foods can manipulate the community structure

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

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BacterioFiles 404 - Phages Force Food Finding

Synechococcus cyanobacteria

This episode: Another climate-related story: Cyanobacteria infected by viruses continue taking up nutrients from their environment, using it to make more viruses than would otherwise be possible!

Download Episode (6.3 MB, 9.2 minutes)

Show notes:
Microbe of the episode: Microcystis virus Ma-LMM01

News item

Takeaways
Though global warming is a global problem, accurate models for predicting where things are headed need to incorporate the activity of even the smallest organisms, if they're numerous enough. Photosynthesis and other activities of microbes in the oceans are a big sink for carbon, but cycles of other nutrients and also viruses can affect the carbon cycle.

In this study, phages infecting photosynthetic ocean bacteria were able to continue their host's uptake of nitrogen from the environment even after mostly shutting down the host's own protein production and growth. This has implications for how viruses affect carbon cycling by cyanobacteria and how quickly populations of these bacteria may grow or die off.

Journal Paper:
Waldbauer JR, Coleman ML, Rizzo AI, Campbell KL, Lotus J, Zhang L. 2019. Nitrogen sourcing during viral infection of marine cyanobacteria. Proc Natl Acad Sci 116:15590–15595.

Other interesting stories:

• Transplants of gut microbes help koalas eat wider range of food
• Skin bacteria can help attract (or repulse) mosquitoes (paper)

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

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BacterioFiles 401 - Phototrophs Fill Fungal Filaments

Algae inside fungal hypha

By Du et al. 2019

eLife e47815

This episode: In this partnership between fungus and algae, the algae eventually take up residence inside their partner!

Download Episode (8.4 MB, 12.1 minutes)

Show notes:
Microbe of the episode: Erwinia tracheiphila

News item/Summary article

Takeaways
Partnerships and cooperation between otherwise free-living organisms is common in the natural world. Partnering with a photosynthetic organism is a smart approach, allowing the partner to get its energy from the sun and making gathering nutrients easier for the phototroph, and possibly offering protection as well. But in most partnerships, each partner stays separated by its own cell membrane.

In this study, a fungus and an alga grow well together, exchanging carbon for nitrogen, similar to how lichens operate. But after a month or so of co-culture, the algae apparently enter the cells of the fungus somehow and live inside it, happily growing and dividing, turning the fungus green.

Journal Paper:
Du Z-Y, Zienkiewicz K, Vande Pol N, Ostrom NE, Benning C, Bonito GM. 2019. Algal-fungal symbiosis leads to photosynthetic mycelium. eLife 8:e47815.

Other interesting stories:

• Skin microbe transplants could produce healthier skin communities
• Algae took genes from bacteria to deal with harsh conditions

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

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BacterioFiles 381 - Chlorophyll Can Convey Cancer Characteristics

Tumor imaging by MSOT
By Peters et al. 2019,
Nat Commun 10:1191, CC BY 4.0

This episode: Pigmented bacteria can be used in a cancer imaging technique that combines light and sound!

Download Episode (8.9 MB, 9.75 minutes)

Show notes:
Microbe of the episode: Streptomyces bellus

Takeaways
Because "cancer" is a general term that describes many different forms of disease affecting different cells in different parts of the body, effective cancer treatment relies on understanding the location and physiology of the cancer in a given patient. New imaging technologies for diagnosis and analysis of cancer and for cancer research can be very valuable, especially if they don't require big investments of money and space.

One promising imaging technology is called multispectral optoacoustic imaging, or MSOT. This uses pulses of light to create vibrations as pigments in tissues absorb the light and undergo thermal expansion; these vibrations are then detected by ultrasound technology. This approach allows good resolution and depth of imaging without large equipment like MRI machines, but the best results require adding pigments into the body.

In this study, scientists showed that the photosynthetic pigments of purple non-sulfur bacteria can be useful in this optoacoustic imaging, providing a somewhat long-term, nontoxic approach. It proved especially interesting when they discovered that the wavelength spectrum changing over time was an indication of macrophage activity in the tumors.

Journal Paper:
Peters L, Weidenfeld I, Klemm U, Loeschcke A, Weihmann R, Jaeger K-E, Drepper T, Ntziachristos V, Stiel AC. 2019. Phototrophic purple bacteria as optoacoustic in vivo reporters of macrophage activity. Nat Commun 10:1191.

Other interesting stories:

• Figuring out the structure of bacterial nanowires

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

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BacterioFiles 379 - Photons Facilitate Faster Flourishing

This episode: Light increases the growth even of some bacteria that don't harvest its energy!

Download Episode (9.0 MB, 9.75 minutes)

Show notes:
Microbe of the episode: Methylococcus thermophilus

News item

Takeaways
Light from the sun is one of the fundamental sources of energy for life on this planet. Plants and other phototrophs—photosynthetic organisms that get their energy mainly from light—form the foundation of the food web, and organisms that feed on them or that feed on organisms that feed on them are all dependent on the ability to capture the sun's rays.

There are other ways to benefit directly from the sun's energy, besides photosynthesis—some microbes have enzymes that use light energy to repair damage to DNA (the same damage that is caused by ultraviolet light), and we use sunlight to synthesize vitamin D.

In this study, however, microbes are discovered to grow faster in the presence of light despite not being phototrophs or producing any light-harvesting proteins. The scientists discover some possible light-sensing proteins, though, that could regulate these microbes' behavior, allowing them to synchronize their growth cycles to phototroph partners in aquatic environments.

Journal Paper:
Maresca JA, Keffer JL, Hempel P, Polson SW, Shevchenko O, Bhavsar J, Powell D, Miller KJ, Singh A, Hahn MW. Light modulates the physiology of non-phototrophic Actinobacteria. J Bacteriol JB.00740-18.

Other interesting stories:

• Finding and capturing electrosynthetic microbes directly from hot springs
• Lignin-eating microbe could be good source for renewable aromatic compounds
• Wood-eating beetle has gut for breaking down wood in microbial production line fashion

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.

BacterioFiles 369 - Powering Purple Prokaryote Protonation

This episode: Purple phototrophic bacteria could use certain kinds of wastewater, along with electric current, to produce valuable products like hydrogen without much waste!

Thanks to Dr. Ioanna Vasiliadou for her contribution!

Download Episode (12.7 MB, 13.9 minutes)

Show notes:
Microbe of the episode: Streptomyces tendae

News item

Takeaways
Purple phototrophic bacteria can take light energy and use it to help power their metabolism. They're not dependent on it like plants, but can use light or other energy sources for their versatile metabolism.

This versatility makes them very interesting candidates for industrial biotechnology applications. These bacteria can take in various combinations of nutrients and produce a number of different valuable products, including protein-rich feed, bioplastics, and biofuels such as hydrogen gas.

Today's study shows they can also take up electrons directly to help make their biofuel production process even more environmentally sustainable.

Journal Paper:
Vasiliadou IA, Berná A, Manchon C, Melero JA, Martinez F, Esteve-Nuñez A, Puyol D. 2018. Biological and Bioelectrochemical Systems for Hydrogen Production and Carbon Fixation Using Purple Phototrophic Bacteria. Front Energy Res 6:107.

Other interesting stories:

• Looking at which microbes degrade classic paintings, and how
• Neurotransmitter-consuming gut microbes correlated with fewer signs of depression (paper)
• Phages don't always transfer the same way in fecal microbe transplants (paper)

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.