The worm turns

In the episode of The X Files called "Ice," Fox Mulder and Dana Scully are sent with a small team of scientists to a remote Arctic research station in order to investigate the murder-suicide of its entire crew.  When they get there, they find one survivor -- the station's mascot, a dog, who shows signs of hyperaggressive behavior (obviously) reminiscent of what afflicted the researchers.

They eventually figure out what happened, but not before two of the people accompanying them are dead, and both Mulder and the third scientist are obviously afflicted with the same malady.  In digging up and thawing out permafrost, the researchers had inadvertently reanimated a deep-frozen parasitic nematode that causes drastic behavioral changes, and is transmissible from bites.  They do find a way to get rid of the infection, saving the lives of Mulder, the infected scientist, and (thank heaven) the dog, but the U.S. government destroys the base before any further study of the worm or its origins can be made.

It's a highly effective and extremely creepy episode, doing what The X Files did best -- leaving you at the end with the feeling of, "This ain't actually over."

I was forced unwillingly to recall my watching of "Ice" by two news stories this week.  In the first, scientists have "reawakened" -- deliberately this time -- a nematode that has been frozen for 46,000 years in the Siberian permafrost.

Dubbed Panagrolaimus kolymaensis, it's a previously unknown species.  This doesn't mean it's a truly prehistoric species; Phylum Nematoda is estimated to contain about a million species, of which only thirty thousand have been studied, classified, and named.  So it could well be that Panagrolaimus exists out there somewhere, in active (i.e. unfrozen) ecosystems, and the invertebrate zoologists just hadn't found it yet.

Still, it's hard not to make the alarming comparison to the horrific events in "Ice" (and countless other examples of the "reanimating creatures frozen in the ice" trope in science fiction).  This reaction is somewhat ameliorated by the fact that two-thirds of the nematode species known are harmless to humans, and even the ones that are parasitic usually aren't life-threatening.  There are a few truly awful ones -- which, for the sakes of the more sensitive members of my audience, I'll refrain from giving details about -- but most nematodes are harmless, so chances are Panagrolaimus is as well.

On the other hand, it doesn't mean that thawing frozen stuff out is risk-free, and the problem is, because of climate change, thawing is happening all over the world even without reckless scientists being involved.  The second study, conducted at the European Commission Joint Research Centre, appeared in a paper in PLOS - Computational Biology and described a digital simulation of a partially frozen ecosystem (that contained living microbes in suspended animation).  They looked at how the existing community would be affected by the introduction of the now reawakened species -- and the results were a little alarming.

It has been tempting to think that because the entire ecosystem has changed since the microbes were frozen, if they were reanimated, there'd be no way they could compete with modern species which had evolved to live in those conditions.  In other words, the thawed species would be unable to cope with the new situation and would probably die out rapidly.  In fact, that did happen to some of them -- but in these models, the ancient microbes often survived, and three percent of them became dominant members of the ecosystem.  

One percent actually outcompeted and wiped out modern species.

"Given the sheer abundance of ancient microorganisms regularly released into modern communities," the authors write, "such a low probability of outbreak events still presents substantial risks.  Our findings therefore suggest that unpredictable threats so far confined to science fiction and conjecture could in fact be powerful drivers of ecological change."

Now, keep in mind that this was only a simulation; no actual microbes have been resuscitated and released into the environment.

Yet.

Anyhow, there you have it.  Something new from the "Like We Didn't Already Have Enough To Worry About" department.  Maybe I shouldn't watch The X Files.  How about Doctor Who?  Let's see... how about the episode "Orphan 55"?  *reads episode summary*  "...about a future Earth so devastated by climate change that the remnants of humanity have actually evolved to metabolize carbon dioxide instead of oxygen..."

Or maybe I should just shut off the television and hide under my blankie for the rest of the day.

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Tooth and claw

Aficionados of The X Files will no doubt recall "Field Trip," which ranks amongst the creepiest, twistiest, most atmospheric episodes they ever did.  Fox Mulder and Dana Scully are charged with investigating the disappearance of a young couple while on a hiking trip -- and after that, their mantra "Trust nothing and no one" becomes literally true.

What had happened (obviously, *spoiler alert*) is that first the couple, and then Mulder and Scully, had been attacked by an underground fungus that works in a particularly insidious way.  Inhaling the spores, which are released whenever you take a step on the ground, induces hallucinations intended to make you hold still while the fungus slowly digests you.  It stimulates your brain with images while dissolving away your body.  Every time the real reality -- the tendrils of slime mold creeping across your skin -- intrudes, the hallucinations become more intense, more engaging, more real.

Until there's nothing left of you to fight back.

While the details of the episode are fiction, nature itself has plenty of examples that are just as horrifying.  The pathogen Toxoplasma gondii, common not only in humans but in domestic cats, wild mice, and rats, alters the brains of the hosts, but each in its own way.  Rats and mice become unafraid of predators, and in fact become attracted to the scent of cat urine; cats and humans become more affectionate -- and neurotic.  Each of those alterations in behavior is engineered by the parasite to maximize its chances of jumping to another host.  Lancet worms (Dicrocoelium dendriticum) parasitize ground-dwelling ants, and induce them to climb blades of grass and simply wait there, because the worm has a second stage of its life cycle in which it has to pass through the digestive tract of a ruminant, like a deer or a cow.  So it basically triggers the ant to commit suicide so it can make the jump.  Worse of all -- and most like the fungus in "Field Trip" -- there are the baculoviruses, which infect caterpillars.  Once parasitized, the caterpillars become attracted to sunlight, so they climb to the very tops of tree branches, where they die.  And then explode, showering their comrades lower down in the tree with viral particles.

Another way that "Field Trip" got it right, though, was some of the nasty stuff pulled by members of kingdom Fungi.  You have to wonder how we ever figured out that any of them were edible:

Not only are some of them amongst the most toxic living things known (the closely-related death cap [Amanita phalloides] and destroying angel [Amanita bisporigera] mushrooms, for example), they have a lot of other insidious strategies.  Most fungi are decomposers, but like the fungus in "Field Trip," a few of them have developed methods for hastening their unfortunate prey into decomposition.

This, in fact, is why the topic comes up; a new study of oyster mushrooms (Pleurotus ostreatus) found that the underground mycelium (network of root-like tubes) of the species actually hunts and kills nematodes (roundworms) using something one of researchers described as "a lollipop filled with nerve gas."  The toxocysts, as the lollipops are called, are consumed by the nematodes, and when they burst, it releases a chemical called 3-octanone, which triggers calcium to flow into the muscles of the worm.  This paralyzes it -- and the fungus has dinner.

Oyster mushrooms aren't the only species that goes after nematodes.  It makes sense to choose them as prey; nematodes are one of most numerous animals in the world.  I still recall my invertebrate zoology professor grossing us all out (something he specialized in) by telling us that if you made all organic matter disappear except for nematodes, you could still see where all the other life forms were by the haze of parasitic nematodes they'd been carrying, outlining where they'd been like some kind of ghostly remnant of their bodies.

But the fungi still maintain the upper hand.  There are fungi which have evolved harpoons for skewering nematodes.  Others create what amount to glue traps.  One species produces something like a spiked collar -- with the spikes pointing inward.  The weirdest one is the fungus Arthrobotrys oligospora, which creates a noose.  When a nematode crawls through the noose, the loop suddenly inflates, strangling the hapless worm, which is then digested.

Nature is red in tooth and claw, man.  And it's not just the animals.  Remember the first line of Stephen King's wonderful novel The Girl Who Loved Tom Gordon: "The world had teeth, and could bite you with them any time it wanted."

Truer words never spoken.

Anyhow, I've probably skeeved you out sufficiently for one day.  Just think about all this next time you see innocent-looking little mushrooms popping up in your lawn. 

You never know what's going on beneath the surface.

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Worm brains

New from the "Haven't These People Ever Watched Horror Movies?" department, we have: some scientists in Austria who have uploaded the brain of a worm into a computer.

The research was done at the Technische Universität Wien (Vienna Technical University), and was done by computer engineers Mathias Lechner, Ramin Hasani, and Radu Grosu.  The worm was Caenorhabditis elegans, well known to researchers in developmental biology as the favorite species for research into how cell specialization unfolds.  The brain of C. elegans only has three hundred neurons, and the connections between them (synapses) are well understood, so what Lechner et al. did was to render the worm's brain as a circuit diagram, and emulated that circuit in a piece of software.

Within short order, they found that they were on to something pretty amazing.  Because the program could learn.  The task was simple -- given a model of a pole balanced on its end, the program had to figure out how to keep the pole upright if its top was moved (by sliding the base until it was upright again).  But it figured out how to do it, and most astonishingly, without having to be shown.

"With the help of reinforcement learning, a method also known as 'learning based on experiment and reward'," Lechner said, "the artificial reflex network was trained and optimized on the computer."  Co-author Grosu added, "The result is a controller, which can solve a standard technology problem – stabilizing a pole, balanced on its tip.  But no human being has written even one line of code for this controller, it just emerged by training a biological nerve system."

Caenorhabditis elegans.  Not one of the big thinkers of the Animal Kingdom.

Of course, this opens up about a million questions.  Once this software has all the bugs worked out, does it then qualify as a life-form?  Most people, faced with this question, say, "Of course not."  I know this because we discuss the possibility of artificial intelligence in my neuroscience class, and when I suggest that a computerized intelligence would be alive, most students respond with a vehement negative.  (Oddly, they are much quicker to accept that a machine could be intelligent than that a machine could classify as alive, and are usually unable to articulate exactly why they feel that way.)

Another, and deeper, question is to what extent this type of trick could be scaled up.  Not that it would be easy; there's a hell of a difference between the three hundred neurons in the brain of C. elegans and the estimated one hundred billion in the human brain.  Because, after all, you not only have to consider the number of neurons, but the number of their potential connections -- a quantity that, after playing around with some estimates, I have concluded is "really freakin' huge."  I'm no computer scientist -- heaven knows, most days I'm doing well to remember where the "on" switch is -- but the thought crosses my mind to wonder if emulating such a complex system in a computer is even theoretically possible.

Whatever the upper limit is, the feat is pretty astonishing.  The authors write:

Through natural evolution, nervous systems of organisms formed near-optimal structures to express behavior.  Here, we propose an effective way to create control agents, by re-purposing the function of biological neural circuit models, to govern similar real world applications.  We model the tap-withdrawal (TW) neural circuit of the nematode, C. elegans, a circuit responsible for the worm’s reflexive response to external mechanical touch stimulations, and learn its synaptic and neural parameters as a policy for controlling the inverted pendulum problem.  For reconfiguration of the purpose of the TW neural circuit, we manipulate a search-based reinforcement learning.  We show that our neural policy performs as well as existing traditional control theory and machine learning approaches. 

A video demonstration of the performance can be viewed at: https://www.youtube.com/watch?v=o-Ia5IVyff8&feature=youtu.be

So while I don't think we're going to be seeing Commander Data joining Starfleet any time soon, this could well be the first step toward machine intelligence.  This is simultaneously thrilling and scary.  Like I said in my opening sentence, all you have to do is watch bad 1960s horror movies to find out how often the super-intelligent robots went berserk and started killing everyone, beginning with the scientists who had created them (usually after said scientists said, "Stand back!  I know how to control it!").  On the other hand, even if the robots do take over, they can't fuck things up much worse than they already are.

So upon reflection, I think I'll welcome our Computerized Worm Overlords.  Even if they never get around to doing much other than keeping poles standing upright, they'll still be ahead of the yahoos who are currently running the country.