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Posts Tagged ‘fungi

“You can swim (uncomfortably) in water at a temperature slightly above freezing; a tiny drop in temperature—or a miracle—allows you to walk on water.”*…

As Elise Cutts explains, making ice requires more than subzero temperatures. The unpredictable process takes microscopic scaffolding, random jiggling and often a little bit of bacteria…

We learn in grade school that water freezes at zero degrees Celsius, but that’s seldom true. In clouds, scientists have found supercooled water droplets as chilly as minus 40 C, and in a lab in 2014, they cooled water to a staggering minus 46 C before it froze. You can supercool water at home: Throw a bottle of distilled water in your freezer, and it’s unlikely to crystallize until you shake it.

Freezing usually doesn’t happen right at zero degrees for much the same reason that backyard wood piles don’t spontaneously combust. To get started, fire needs a spark. And ice needs a nucleus — a seed of ice around which more and more water molecules arrange themselves into a crystal structure.

The formation of these seeds is called ice nucleation. Nucleation is so slow for pure water at zero degrees that it might as well not happen at all. But in nature, impurities provide surfaces for nucleation, and these impurities can drastically change how quickly and at what temperature ice forms.

For a process that’s anything but exotic, ice nucleation remains surprisingly mysterious. Chemists can’t reliably predict the effect of a given impurity or surface, let alone design one to hinder or promote ice formation. But they’re chipping away at the problem. They’re building computer models that can accurately simulate water’s behavior, and they’re looking to nature for clues — proteins made by bacteria and fungi are the best ice makers scientists know of.

Understanding how ice forms is more than an academic exercise. Motes of material create ice seeds in clouds, which lead to most of the precipitation that falls to Earth as snow and rain. Several dry Western states use ice-nucleating materials to promote precipitation, and U.S. government agencies including the National Oceanic and Atmospheric Administration and the Air Force have experimented with ice nucleation for drought relief or as a war tactic. (Perhaps snowstorms could waylay the enemy.) And in some countries, hail-fighting planes dust clouds with silver iodide, a substance that helps small droplets to freeze, hindering the growth of large hailstones.

But there’s still much to learn. “Everyone agrees that ice forms,” said Valeria Molinero, a physical chemist at the University of Utah who builds computer simulations of water. “After that, there are questions.”…

More at: “The Enduring Mystery of How Water Freezes,” from @elisecutts in @QuantaMagazine.

Even more at “Cold, colder and coldest ice” (source of the image above)

* Meteorologist Craig Bohren

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As we contemplate crystallization, we might send chilly birthday greetings to a man fascinated by ice and its crystalline structure, Walther Hermann Nernst; he was born on this date in 1864. A physicist and physical chemist, he made material contributions to thermodynamics, physical chemistry, electrochemistry, and solid-state physics. But he is best remembered for the Nernst heat theorem, which stated that the entropy (a thermodynamic measure of disorder) in a system approaches zero as the temperature goes towards absolute zero… which led to the development of what Nernst himself called “the third law of thermodynamics,” and to Nernst’s receiving the 1920 Nobel Prize in Chemistry.

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“The most outstanding feature of life’s history is a constant domination by bacteria”*…

Jennifer Kahn interviews biochemist Jennifer Doudna (who won the Noel Prize for the gene-editing engine Crispr) on her new focus– our microbiomes, tackling everything from immune disorders and mental illness to climate change—all by altering microbes in the digestive tract…

… what isn’t the microbiome responsible for? It’s been all the rage for the past few years, with scientists hoping it could help treat everything from immune disorders to mental illness. How exactly that will work is something we’re just starting to explore. This spring, the effort got a boost when UC Berkeley biochemist and gene-editing pioneer Jennifer Doudna, who won a Nobel Prize in 2020 for coinventing Crispr, joined the pursuit. Her first order of business, spearheaded by Berkeley’s Innovative Genomics Institute: fine-tuning our microbiome by genetically editing the microbes it contains while they’re still inside us to prevent and treat diseases like childhood asthma. (Full disclosure: I teach at Berkeley.) Oh, she also wants to slow climate change by doing the same thing in cows, which are collectively responsible for a shocking amount of greenhouse gas.

As someone who has written about genetic engineering in the past, I have to admit that my first reaction was: No way. The gut microbiome contains around 4,500 different kinds of bacteria plus untold viruses, and even fungi (so far: in practice we’ve only just started counting) in such massive quantities that it weighs close to half a pound. (Microbes are so tiny that 30 trillion bacteria would weigh roughly 1 ounce. So half a pound is a lot.)

Figuring out which ones are responsible for which ailments is tricky. First you need to know what’s causing the problem: like maybe something is producing too much of a particular inflammatory molecule. Then you have to figure out which microbe—or microbes—is doing that, and also which gene within that microbe. Then, in theory, you can fix it. Not in a petri dish, but in situ—meaning in our fully active, roiling, squishing stomach and intestines while they continue to do all the stuff they usually do.

Until recently, it would have seemed insane—not to mention literally impossible—to edit all the microbes belonging to a species within a vast ecosystem like our gut. And to be fair, Doudna and her collaborator, Jill Banfield, still don’t know quite how it will work. But they think it can be done, and in April, TED’s Audacious Project donated $70 million to support the effort. My own gut feeling (right?) was that this was either brilliant or terrifying, or possibly both at once. Brilliant because it had the potential to head off or treat diseases in an incredibly targeted and noninvasive way. Terrifying because, well, you know … releasing a bunch of inert viruses equipped with gene-editing machinery into the vital ecosystem that is our gut microbiome—what could go wrong? With that in mind, I invited Jennifer Doudna to my house for a chat about the future of microbiome medicine…

Fascinating– and encouraging: “Crispr Pioneer Jennifer Doudna Has the Guts to Take On the Microbiome,” in @WIRED.

(Image above: source)

* Stephen Jay Gould

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As we investigate our intestines, we might spare a thought for Guido Pontecorvo; he died on this date in 1999. A geneticist, he discovered the process of genetic recombination in the common soil fungus Aspergillus— and as a result the parasexual cycle— in what became the model for the genetic studies in many other fungi. This cycle gives rise to genetic reassortment by means other than sexual reproduction; its discovery provided a method of genetically analyzing asexual fungi…. which, as noted above, populate our microbiomes.

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Written by (Roughly) Daily

September 24, 2023 at 1:00 am

“Attend to mushrooms and all other things will answer up”*…

Travis Boyer: Crush Blue, 2020

The living– and conscious?– infrastructure of the biosphere…

Imagine that you are afloat on your back in the sea. You have some sense of its vast, unknowable depths—worlds of life are surely darting about beneath you. Now imagine lying in a field, or on the forest floor. The same applies, though we rarely think of it: the dirt beneath you, whether a mile or a foot deep, is teeming with more organisms than researchers can quantify. Their best guess is that there are as many as one billion microbes in a single teaspoon of soil. Plant roots plunge and swerve like superhighways with an infinite number of on-ramps. And everywhere there are probing fungi.

Fungi are classified as their own kingdom, separate from plants and animals. They are often microscopic and reside mostly out of sight—mainly underground—but as Merlin Sheldrake writes in Entangled Life: How Fungi Make Our Worlds, Change Our Minds and Shape Our Futures, they support and sustain nearly all living systems. Fungi are nature’s premiere destroyers and creators, digesting the world’s dead and leaving behind new soil. When millions of hair-like fungal threads—called hyphae—coalesce, felting themselves into complex shapes, they emerge from the ground as mushrooms. A mushroom is to a fungus as a pear is to a pear tree: the organism’s fruiting body, with spores instead of seeds. Mushrooms disperse spores by elaborate means: some species generate puffs of air to send them aloft, while others eject them by means of tiny, specialized catapults so they accelerate ten thousand times faster than a space shuttle during launch.

But Sheldrake is most interested in fungi’s other wonders—specifically, how they challenge our understanding of nonhuman intelligence and stretch the notion of biological individuality. Fungi infiltrate the roots of almost every plant, determining so much about its life that researchers are now asking whether plants can be considered plants without them. They are similarly interwoven throughout the human body, busily performing functions necessary to our health and well-being or, depending on the fungi’s species and lifestyle, wreaking havoc. All of this prompts doubts about what we thought we knew to be the boundaries between one organism and another…

ungi themselves form large networks of hyphae strands in order to feed. These strands, when massed together, are called mycelium. The total length of mycelium threaded through the globe’s uppermost four inches of soil is believed to be enough to span half the width of our galaxy. Mycelium is constantly moving, probing its surroundings in every direction and coordinating its movements over long distances. When food is found—a nice chunk of rotting wood, for example—disparate parts of the mycelium redirect to coalesce around it, excrete enzymes that digest it externally, and then absorb it. As Sheldrake puts it, “The difference between animals and fungi is simple: Animals put food in their bodies, whereas fungi put their bodies in the food.”

Fungi are literally woven into the roots and bodies of nearly every plant grown in natural conditions. “A plant’s fungal partners,” Sheldrake writes, “can have a noticeable impact on its growth.” In one striking example, he describes an experiment in which strawberries grown with different fungal partners changed their sweetness and shape. Bumblebees seemed able to discern the difference and were more attracted to the flowers of strawberry plants grown with certain fungal species. Elsewhere he discusses an experiment in which researchers took fungi that inhabited the roots of a species of coastal grass that grew readily in saltwater and added it to a dry-land grass that could not tolerate the sea. Suddenly the dry-land grass did just fine in brine.

Much has been written lately about trees communicating and sharing resources among themselves; healthy trees have been documented moving resources toward trees that have fallen ill. This is often characterized as friendship or altruism between trees, but it is not at all clear whether trees pass information or nutrients intentionally. What is clear, though, is that the fungal networks entwined in every tree root make this communication possible. “Why might it benefit a fungus to pass a warning between the multiple plants that it lives with?” Sheldrake asks. The answer is survival. “If a fungus is connected to several plants and one is attacked by aphids, the fungus will suffer as well as the plant,” he writes. “It is the fungus that stands to benefit from keeping the healthy plant alive.”…

Fungi are genetically closer to animals than to plants, and similar enough to humans at the molecular level that we benefit from many of their biochemical innovations. In fact, many of our pharmaceuticals are borrowed innovations from fungi. Penicillin, discovered in 1928 by the Scottish researcher Alexander Fleming, is a compound produced by fungus for protection against bacterial infection. The anti-cancer drug Taxol was originally isolated from the fungi that live inside yew trees. More than half of all enzymes used in industry are generated by fungi, Sheldrake notes, and 15 percent of all vaccines are produced using yeast. We are, as he puts it, “borrowing a fungal solution and rehousing it within our own bodies.”..

We know that fungi maintain “countless channels of chemical communication with other organisms,” and that they are constantly processing diverse information about their environment. Some can recognize color, thanks to receptors sensitive to blue and red light, though it is not entirely clear what they do with that information. Some even have opsins, light-detecting proteins also found within the rods and cones of the animal eye. One fungus, Phycomyces blakesleeanus, has a sensitivity to light similar to that of a human eye and can “detect light at levels as low as that provided by a single star” to help it decide where to grow. It is also able to sense the presence of nearby objects and will bend away from them before ever making contact. Still other fungi recognize texture; according to Sheldrake, the bean rust fungus has been demonstrated to detect grooves in artificial surfaces “three times shallower than the gap between the laser tracks on a CD.”

Can fungi, then, be said to have a mind of their own? That is, as Sheldrake puts it, a “question of taste”—there is no settled scientific definition for “intelligence,” not even for animals. The Latin root of the word means “to choose between,” an action fungi clearly do all the time. But the application of this kind of term to fungi is loaded with something more mystical than that simple definition and demands a willingness to rattle our sense of where we ourselves fall in the imagined hierarchy of life. If fungi can be said to think, it is a form of cognition so utterly different that we strain to see it.

After all, philosophers of mind like Daniel Dennett argue that drawing any neat line between nonhumans and humans with “real minds” is an “archaic myth.” Our brains evolved from nonmental material. “Brains are just one such network,” Sheldrake writes, “one way of processing information.” We still don’t know how the excitement of brain cells gives rise to experience. Can we really dismiss the possibility of cognition in an organism that clearly adapts, learns, and makes decisions simply based on the lack of a brain structure analogous to ours?

Perhaps there is intelligent life all around us, and our view is too human-centric to notice. Are fungi intelligent? Sheldrake reserves judgment, deferring instead to scientific mystery: “A sophisticated understanding of mycelium is yet to emerge.” Still, after spending long enough in the atmosphere of Sheldrake’s sporulating mind, I began to adopt the fungal perspective. I can’t help now but see something like a mind wherever there might be fungal threads—which is to say everywhere, a mesh-like entangled whole, all over the earth.

Fungi challenge our understanding of nonhuman intelligence and complicate the boundaries between one organism and another: “Our Silent Partners“– Zoë Schlanger (@zoeschlanger) reviewing Merlin Sheldrake’s Entangled Life: How Fungi Make Our Worlds, Change Our Minds and Shape Our Futures in @nybooks.

Why did the mushroom go to the party? Because he was a fungi.” – Lewis Tomlinson

* A. R. Ammons

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As we ponder partnership, we might spare a thought for Jens Wilhelm August Lind; he died on this date in 1939. An apothecary, botanist and mycologist, he published a full account of all fungi collected in Denmark by his teacher, Emil Rostrup. Combining his pharmaceutical and mycological knowledge, he was early in experimenting with chemical control of plant pathogens.

Lind also collaborated with Knud Jessen on an account on the immigration history of weeds to Denmark.

Gravestone of Jens Lind and wife Gunild, at Viborg Cemetery

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“The poets have been mysteriously silent on the subject of cheese”*…

The blue-green marbling of fungus that makes Blue (or as purists might have it, Bleu) Cheese blue is a delight to some, but a horror to others.  Now Roquefort-refusers have a new reason to demur…

Until pretty recently, a big chunk of fungal species were thought to reproduce without sex–until people really started to look. It turns out, there’s a lot more sex going on in the fungal world (on the down-low) than people thought. And that includes fungi that are used to make delicious blue cheese. Jeanne Ropars and colleagues in France, the home of Roquefort cheese, looked at the genomes of the mold species used in this particular cheese to see what kind of funny business was going on in their snack of choice. They found much more diversity than could be explained by asexual reproduction. And even more telling, the genes used by fungi to find mating partners have been kept intact and functional by evolution, meaning there’s probably some sex going on…

So far, no one has actually seen this mold having sex. But it could be. It could be doing it right now. Who knows what kind of awesome super-cheese could be evolving, right under your nose?

Read the full story at Molecular Love (and Other Facts of Life); and find the research paper to which it refers here.

* G.K. Chesterton (though this news could be just what it takes to attract poets into the mold…  er, fold.)

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As we put away the saltines, we might send inventive birthday greetings to David Wilkinson; he was born on this date in 1771.  A mechanical engineer and machinist, Wilkinson (no known relation to your correspondent) played a key role in the development of machine tools in the U.S. (initially in the textile industry):  he invented the lathe and process for cutting screws.

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Written by (Roughly) Daily

January 5, 2013 at 1:01 am

Nature is not unlike your lower intestine: stinky and loaded with danger*…

 

Good advice above. The pointy end belongs to the viperfish, whose teeth are so long that they have to curve around its face when it closes its mouth. Fishbase says that it’s “harmless” to humans, which is exactly what the viperfish wants you to think.

Source: Pacificoceanwork

From the giant squid to the humble hook worm, readers will find a compendium of carnivorous creatures at Nature Wants to Eat You.

* a paraphrase of Ace Ventura (from Ace Ventura: When Nature Calls)

 

As we rethink that picnic, we might might send hearty birthday wishes to botanist Albert Francis Blakeslee; he was born on this date in 1874.  While Blakeslee contributed to our store of natural knowledge in a variety of ways (e.g., he became an expert on the poisonous jimsonweed via his use of it in genetic experiments), he is probably best remembered for his pioneering work on the sexuality of fungi.

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Written by (Roughly) Daily

November 9, 2011 at 1:01 am