Life without water

Imagine, for a moment, something that means "life" to you. What do you see?

A tree?

A vibrant reef?

One of those tiny humans your friends are always talking about?

You may notice that all of those things have something in common--they have a whole boatload of water in them.

Refreshing.

You see, dear reader, here on planet Earth water is considered to be the "solvent of life". Water dissolves more compounds than any other solvent known to humanity. It plays a crucial role in a huge number of biochemical processes--there are so many enzymes that require water to function that I can't even. Water can be found in all three phases of matter in our planetary climate (here's hoping we still have the solid form in a few centuries). Speaking of which, water also helps regulate our climate because of its high heat capacity.

Wow. H2O sounds pretty sweet, in a flavorless sort of way. No wonder everyone gets so excited when NASA releases another report with evidence of water on Mars.

As sarcastic as those reports might be.

Ok, so, real talk for a minute. You already know I'm not going to just talk about how great water is, because you read the title of this post. What, then, will I suggest as an alternative?

It turns out there are several that people much smarter than I have bandied about. One that could exist in our own solar system is methane. On Titan, one of Saturn's moons, it is so cold that small hydrocarbons like methane and ethane are liquid. There are vast oceans and rivers of the stuff, and when it rains, you bet your bottom it's raining men. I mean, methane.

Artist renderings are the best renderings.

Of course, it is quite chilly on Titan (-179°C, or -290°F, whichever is your poison), so things would probably happen much slower than they do here on Earth. Another option is formamide, which has a large range of temperatures in which it is liquid and can do things like help synthesize DNA bases (a comforting fact for us Earthlings). More promising still is ammonia, which is liquid in about the same temperature range as water (-107°F to 204°F), as long as you crank up the atmospheric pressure to 60 times what we're used to. It's also great at dissolving lots of different things, which is handy if you'd like to synthesize lots of different things.

Needless to say, we'll really have to think outside the box and keep our minds open to even find life of this sort--by necessity, it would be completely different from what we're used to. So how would we find these lifeforms, if indeed they do exist?

Let us harken back to middle school science class, or some similarly far away time, wherein we learned of:

Our first step is to conceive a hypothesis! Now, we know that any life form, big or small, watery or methaney, must 1) consume things, 2) convert these things to other things to obtain energy, and 3) excrete the byproducts of conversion. For example, plants consume sunlight, water, and carbon dioxide to produce glucose, and they excrete oxygen.

Therefore, if we observe a region that is becoming depleted in carbon dioxide and enriched in oxygen, we might assume that there are plants there. Perhaps you now see where I am going. We do not know how strange, non-water-based beings might work, but we do know how chemistry works. If we take a system, say Titan, and we lay out all of the chemicals and environmental conditions (temperature, pressure, weather patterns) that are likely to occur there, we can start to think about what reactions could take place there, and then reduce that down to the reactions that would give off energy for an organism to use.

At that point, we have hypotheses to test. We could put forth that an organism can consume hydrogen, acetylene, and ethane for energy, and exhale methane as a waste product. Now we mosey on over to Titan and we start looking for the disappearance of hydrogen, acetylene, and ethane, combined with a mysterious increase in methane. Is it life? Maybe not. But from here we can make further assumptions and test them, and so on and so forth.

And you know what's funny? It does seem like there is some "unkown process" consuming--you guessed it--hydrogen, acetylene, and ethane on the surface of Titan....

Reference for that last zinger: Stevenson J, Lunine J, & Clancy P (2015). Membrane alternatives in worlds without oxygen: Creation of an azotosome. Science Advances 1(1):e1400067. doi: 10.1126/sciadv.1400067

Why alcohol burns a cut

If, like most non-robotic megafauna, you've ever had the misfortune of cutting yourself, chances are that at some point you have poured alcohol on that bad boy to ward off infection.

Also included in the category "megafauna". In case you were feeling too pleased with yourself.

Chances are also high that you immediately regretted this decision, because it made what may have been a fairly minor pain a whole lot worse.

Despite how common this experience I'm describing is, not very many people know the reason behind it. Luckily, for the sake of this post, I am one of those people.

As you are probably aware, you have the ability to sense heat and cold.

This is because there are proteins on the surface of our cells called temperature sensitive channels. When you stick your hand in a fire, they're what tells you, "Hey! That's hot!" Let's get some perspective on where these things are in our bodies.

These channels open and close depending on the ambient temperature. The stuff that they then let in or out interacts with other proteins in your cells propagating the signal until it reaches someone that does something about it.

Now when you douse these channels with alcohol, speaking of the heat-responsive channels in particular, it changes how they respond to temperature. In essence, it lowers their "threshold", which we can think of as the temperature where it tells your cells to freak out. Alcohol puts that threshold so low that your own body temperature causes the channels to open! Thus it makes your body think that you're burning when really you're just existing.

There are other things besides heat (or lack thereof) and alcohol that affect these channels. Spicy food is described as "hot" for a reason--capsaicin, the active ingredient in peppers, binds to heat-sensitive channels and activates them. A common side effect of menthol and eucalyptus oil is a cooling sensation, which you can probably surmise comes from activation of cold-sensitive channels.

Now you know why this stuff confuses your mouth so much.

Microbiota, invasive species, and Star Trek

So I've had a notion knockin' around in my noggin, and for once it doesn't involve me just regurgitating interesting facts at you. You may have noticed that the title of this post seems somewhat...erratic. Don't worry, we'll clear up that confusion posthaste.

As my fellow Trekkies well know, the crew of the starship Enterprise (my personal favorite was NC 1701-D, but this applies to all) were frequent visitors to new and unknown worlds, many of which happened to have their own suspiciously humanoid* life forms.

Now, those of us who are up to date on our yogurt commercials will also know that the human body, and indeed every multicellular organism we've dared to study, is just brimming with bacteria, viruses, and even a few fungi for funsies. Thusly, it is fairly safe to assume that if we did find other multicellular life, those life forms would probably be teeming with unicellular organisms themselves.

And if in addition to a working knowledge of Star Trek and fermented dairy products you also know that a baby giant tortoise has not been seen in the Galapagos isles for over a century because of rats introduced by humans, then either you see where this is going or you need another cup of coffee!

That's right! I'm wondering why none of the aliens ever get irritable bowel syndrome from being visited by humanity!

Sorry, that might have been too much of a leap. Basically, would we even be allowed on another civilization's planet? Smallpox wiped out the Native Americans, could our microbiota not just as easily massacre innocent Martians? Conversely, perhaps the Martians would inadvertently massacre us!

At the same time, one has to recognize that microbes have evolved to inhabit absolutely every single ecological niche in which earthly life can exist. This raises the point that perhaps there would be no niche for a human microbe to invade on planet Vulcan. They're all full!

I regret to say that I don't have enough frequent flyer miles to get to Romulus right now, so I have no empirical evidence to sway you one way or the other. But maybe this is something to think about when we finally do find our way to the stars.

*If you remember the two part episode in The Next Generation where they explain this, let's be friends.

Where do animals go in the winter? The tale of the wood frog

I spent the first 18 years of my life in North Carolina, and I can count the number of times it snowed in my hometown (village, really) on one hand. Now that I've moved to Wisconsin, deep in the frigid North, I find myself wondering every year around November where all the little critters go in anticipation of the impending deluge of snowflakes. Birds obviously migrate South, and bears hibernate in cozy holes, but what about squirrels and rabbits?
Optional digression: Earlier this year I met two baby bunnies! There are a ton of rabbits around my apartment complex. One evening I was walking up to the front door when I noticed some movement. Being a nature enthusiast, I stopped immediately because I suspected there might be an interesting critter in the vicinity. Sure enough, two little bunlets (if that's not the term, it should be) and their mama were in the grass right in front of my building. I crouched down to try to look less threatening, and one of the little fellows hopped right up to my foot! He (or she) touched me! I have high hopes for that bunlet and his family.

HE'S SO CUTE

Back to original story! It's entirely possible, I suppose, that other furry creatures also migrate in the harsher months, but what about snakes and frogs and insects? Surely they don't ALL migrate. So, I've been curious for several winters and I finally bothered to do some in-depth research (i.e., I googled it). Because this topic has already been covered by other intrepid bloggers, I've included a bonus look into the life of the wood frog!

It turns out that two of the animals I mentioned before, squirrels and rabbits, actually stay active in the winter and just do their best to find food and keep warm in trees and burrows [1]. Chipmunks, on the other hand, hibernate like bears [2].

Reptiles like snakes will also take shelter in burrows. Fish will move to the bottom of lakes and ponds where the water won't freeze, and turtles and frogs hide out in water bodies too, entering a dormant state and absorbing oxygen from the water through their skin [3].
Some insects, such as the silkworm Bombyx mori, will enter a hibernation-like state called diapause during the winter [4]. Others lay eggs which will hatch in the spring, then die. Still others simply hang out in various hidey-holes (tree bark, fallen logs, dirt). An interesting variation on this theme is the gall. You've probably seen plants that seemed to have warts, like so:

Ewwwwwwww

This is actually a wee insect's home. Bugs like eriophyid mites secrete compounds that bulge out the plant tissues, then live there and munch on the plant throughout the winter like a bunch of degenerates [5].
And then there's the wood frog. Rana sylvatica, much like Geobacter sulfurreducens (I have a blog post on that, too!), just doesn't give a fuck.

Pretty cool background, huh? Even if it's not as cool as Arya. I got it here.

These frogs can survive being frozen in the winter, so when it starts to get nippy they just hunker down under some dead leaves near a woodland pool (gotta be ready to start making babies in the spring) and turn into frog cubes.

Like this. Except, you know, frog.

Yeeeeeaaaahhhhh.

They are able to do this because they accumulate cryoprotectants--antifreeze*, basically--in their blood and tissues to decrease the formation of ice crystals that would rip their cells open. Soooper cool (that was a pun).
I'll leave you with this video of scientists playing with frozen wood frogs because...science?

*Not technically true. Antifreeze prevents freezing, while these compounds minimize the size of ice crystals that form, which reduces the stress on the cells (less stabby stabby = good). They do also prevent freezing to some extent because of freezing point depression, but that does not seem to be their main purpose. There ARE critters that have antifreeze in their blood (some Antarctic fishes come to mind), but those are a topic for another day :)




References:

1. http://wdfw.wa.gov/living/rabbits.html
2. http://animals.nationalgeographic.com/animals/mammals/chipmunk/
3. http://www.newton.dep.anl.gov/natbltn/400-499/nb485.htm
4. Okitsugu Yamashita (1996). Diapause hormone of the silkworm, Bombyx mori: Structure, gene expression and function. Journal of Insect Physiology 42(7):669-679.
5. Robert Wawrzynski, Jeffrey Hahn, and Mark Ascerno (2005). Insect and mite galls. University of Minnesota. http://www.extension.umn.edu/garden/insects/find/insect-and-mite-galls/

Self-medication in animals

Hi there! Did you know that when your dog eats grass, it's probably because it has an upset stomach and is trying to puke/poop out the problem? Apparently other animals do that too! I found this neat article while traversing the interwebs this morning.Give it a read!

News Feature: Animals that self-medicate by Joel Shurkin