Bacteriofiles

This episode: Despite being photosynthetic, some kinds of algae engage in predatory behavior, hunting and consuming live bacteria! 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 P

This episode: Lighting in caves open to tourists supports the growth of unwanted photosynthetic bacteria! 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 t

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–

Finally found some good stories, so we're back! This episode: How slime molds encode and use memories built into their own bodies! Download Episode (4.6 MB, 6.7 minutes) Show notes: Microbe of the episode: Aeromonas salmoncida News item   Takeaways Despite being single-celled organisms, slime molds have fairly complex behavior, including a basic form of memory. They often grow as a network of tubes of cytoplasm branching out from one place to find and exploit new sources of food in their environment. When these tubes connect to new food, other less productive branches of its body shrink away.   As it turns out, this body form serves a role in memory also. This study determined that the slime mold's tubes undergo constant squeezing, which moves cell contents around and also shrinks them. When tubes are connecting to a food source though, they secrete a softening agent that allows the pressure to expand the tubes instead of shrinking them. These larger tubes consequently are capable of transporting more sof

This episode: Giant bacteria with many chromosomes in each cell carry extra genes to help them live in many different environments! Download Episode (8.7 MB, 12.7 minutes) Show notes: Microbe of the episode: Propionibacterium virus SKKY News item   Takeaways We think of bacteria a certain way: too small to see and having mostly just a single large chromosome with all the genes they need for their lifestyle and not much more. And most bacteria are like that. But not all! Giant bacteria exist, some of which can be so large that individual cells can be seen without a microscope.   Achromatium species are one such kind of bacteria. They form clumps of minerals that take up most of their internal volume, but their cells are big enough to see and handle. In order to supply all parts of their vast innards with proteins, they have many copies of their chromosome distributed throughout their cytoplasm.   In this study, a survey of Achromatium genomes from all different kinds of ecosystem revealed that even differe

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,

This episode: Engineered bacteria encapsulated in little beads sense chemicals from landmines and give off light! Download Episode (6.4 MB, 9.3 minutes) Show notes: Microbe of the episode: Bifidobacterium pullorum Takeaways Landmines are a good way to take an enemy by surprise and do some damage. They're so good that some places in the world still aren't safe to go decades after a conflict, due to intact landmines hidden in the area. In order to detect them from a distance to aid in disarming efforts, we need something very good at detecting the faint odor they give off—something like bacteria!   In this study, bacteria are engineered to detect breakdown products of TNT in landmines and produce light—bioluminescence. These bacteria are encapsulated in polymer beads and are stable for months in the freezer, and could accurately pinpoint a landmine buried in sand for a year and a half.   Journal Paper: Shemer B, Shpigel E, Hazan C, Kabessa Y, Agranat AJ, Belkin S. Detection of buried explosives with immobi

This episode: An interesting bacterial genetic element protects against viruses in a unique way! Download Episode (7.1 MB, 10.3 minutes) Show notes: Microbe of the episode: Mongoose associated gemykibivirus 1 News item Takeaways Even single-celled, microscopic organisms such as bacteria have to deal with deadly viruses infecting them. And while they don't have an immune system with antibodies and macrophages like we do, they still have defenses against infection, mostly based on sensing and destroying viral genomes. Restriction enzymes cut viral genomes at specific places, and CRISPR/Cas targets and destroys specific viral sequences. Knowing this, when microbiologists contemplate a strange genetic element of unknown function in bacteria, it's worth considering that it may be relevant to defense against phages.   The strange element in this case is retrons: a special reverse transcriptase enzyme takes a short non-coding RNA transcript and transcribes it into DNA, then links the RNA and DNA sequences togeth

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.   Jour

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

This episode: A fungus-infecting virus transforms the fungal foe into a friend of its host plant! Download Episode (6.1 MB, 8.9 minutes) Show notes: Microbe of the episode: Hepacivirus J   News item Takeaways Viruses can be useful for treating various diseases, especially bacterial infections and cancer. Their ability to target certain cell types specifically makes them great at hunting down and killing disease-causing cells without harming the body's healthy tissue. And just as bacteriophages can work to treat bacterial disease in us, fungal viruses could help to treat serious fungal infections in crop plants.   In this study, a fungus-infecting virus goes beyond treating a deadly fungal disease in rapeseed plants. Fungus infected with this virus no longer causes disease, but lives in harmony with the host plant, protects it from other fungal diseases, and even helps it to grow better.   Journal Paper: Zhang H, Xie J, Fu Y, Cheng J, Qu Z, Zhao Z, Cheng S, Chen T, Li B, Wang Q, Liu X, Tian B, Collinge DB

This episode: Bacteria pay for the privilege of cruising around soil on fungus filaments! Download Episode (7.7 MB, 11.2 minutes) Show notes: Microbe of the episode: Clostridium acetobutylicum News item Takeaways In the complex environment of soil, many different kinds of organisms coexist. Some compete with each other, while others cooperate in fascinating interactions. One example is how bacteria can swim through a film of water surrounding the filaments of fungi, allowing them to traverse more quickly and reach new locations.   In this study, an interaction between fungus and bacterium is discovered in which the bacteria benefit from the fungus in enhanced ability to travel, and the fungus benefits by absorbing vitamins that the bacteria produce.   Journal Paper: Abeysinghe G, Kuchira M, Kudo G, Masuo S, Ninomiya A, Takahashi K, Utada AS, Hagiwara D, Nomura N, Takaya N, Obana N, Takeshita N. 2020. Fungal mycelia and bacterial thiamine establish a mutualistic growth mechanism. Life Sci Alliance 3(12):202

This episode: Bacteria protect farmed mushrooms from damage by other bacteria by breaking down their toxins! Download Episode (4.9 MB, 7.1 minutes) Show notes: Microbe of the episode: Tomato mosaic virus Takeaways Almost all organisms are vulnerable to pathogenic microbes that make them sick or cause damage. Most also have other microbes that help them grow better or protect them from pathogens. This includes animals, plants, and also fungi. In this study, bacterial pathogens produce a toxin that causes button mushrooms to turn brown and rot. However, other bacteria can degrade this toxin and protect the fungus, and can also degrade molecules the pathogens produce to help them swarm to new places, restricting their movement. Journal Paper: Hermenau R, Kugel S, Komor AJ, Hertweck C. 2020. Helper bacteria halt and disarm mushroom pathogens by linearizing structurally diverse cyclolipopeptides. Proc Natl Acad Sci 117:23802–23806. Email questions or comments to bacteriofiles at gmail dot com. Thanks for listenin

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 K

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, Had

This episode: Copper electrodes, rather than killing bacteria in microbial fuel cells, allow them to generate higher densities of electric current! Download Episode (5.0 MB, 7.2 minutes) Show notes: Microbe of the episode: Xipapillomavirus 2   News item Takeaways Copper is widely used as a way to make surfaces and materials antimicrobial, to cut down on the spread of pathogens in hospitals and other environments. Among other mechanisms, it reacts with oxygen to form reactive oxygen species that are very harsh on microbial proteins. But copper is also a good electrical conductor, which would be useful to use in microbial fuel cells, which exploit bacterial metabolism to generate electricity. Microbes form biofilms on an electrode and transfer electrons to it as a way for them to generate energy. Most such fuel cells have used graphite electrodes to avoid toxicity.   In this study, fuel cell bacteria grew well on a copper electrode in an oxygen-free environment. The copper actually allowed them to increase t

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 t

This episode: Large phage discovered that contains a compact version of the CRISPR/Cas defense/gene editing system! Download Episode (5.9 MB, 8.6 minutes) Show notes: Microbe of the episode: Stenotrophomonas virus IME13 News item Takeaways CRISPR/Cas systems have made a lot of things in gene editing much easier in certain organisms. It's almost as easy as just getting the cells to produce the Cas protein and putting in an RNA sequence to tell it where to go! But in some cases, these requirements are too much to work well.   In this study, a more compact version of CRISPR/Cas was discovered in large bacteriophages. These systems help the viruses compete with other viruses and defend against host defenses sometimes. The Cas protein is half the size of the standard Cas most used in gene editing, and it has fewer other requirements to function in new cells, so it could be better in versatility and potential in applications with strict space constraints. Journal Paper: Pausch P, Al-Shayeb B, Bisom-Rapp E, Ts

This episode: A probiotic can protect intestine-like cell growths from destruction by pathogens, but it can also be infected by a virus that makes it more harmful to intestinal cells! Download Episode (6.9 MB, 10.1 minutes) Show notes: Microbe of the episode: Euphorbia yellow mosaic virus   News item Takeaways There are many strains of Escherichia coli. Some are pathogenic, in the gut or the urinary tract, and a subset of those are very dangerous, such as the enterohemorrhagic O157:H7 strain. Many others are commensals, living peacefully as part of our gut community. And some strains can be beneficial to the host, protecting from and reducing the severity of disease. One such strain is called E. coli Nissle.   This study used an advanced model of human intestines called organoids, where stem cells are induced to develop into hollow spheres of intestinal epithelium in which all cell types of a normal intestinal wall are represented. E. coli pathogens typically destroy these organoids and escape from inside,

This episode: Bacteria living in the driest place on earth have ways to extract water from the mineral structures of rocks! Download Episode (3.7 MB, 5.4 minutes) Show notes: Microbe of the episode: Irkut lyssavirus   News item Takeaways Microbes living in extremely dry conditions have it tough. Water is important both for the chemistry and structure of all cells. Desert microbes are very good at acquiring and holding on to the water they can find, but in places such as the Atacama Desert in Chile, there's almost none available.   However, microbes can be very resourceful. In this study, phototrophs were discovered that can actually extract water molecules bound up in the crystalline structure of the mineral gypsum, and this allows them to survive in hyperarid regions. They do this by secreting organic acid molecules to etch the rock and release the water, converting gypsum to anhydrite, which is a mineral with the same chemical structure except without the water. Journal Paper: Huang W, Ertekin E, Wang