Bugs in our gut

Stumbling along the cybernet, I came across this intriguing article about the extinction of our intestinal flora. The tag line here is:

Having evolved along with the human species, most of the miniscule beasties that live in and on us are actually helping to keep us healthy, just as our well-being promotes theirs. In fact, some researchers think of our bodies as superorganisms, rather than one organism teeming with hordes of subordinate invertebrates.

The human body has some 10 trillion human cells—but 10 times that number of microbial cells. So what happens when such an important part of our bodies goes missing?

It’s hard to appreciate just how symbiotic our relationship is. In fact, the flora has a collective metabolic activity equal to a virtual organ within an organ. Our body is well attuned to this fact: immunosensory cells can actually distinguish pathogenic bacteria from the helpful ones. So what are the functions of this virtual organ?

Well, they actually help us to break down some undigested carbohydrates; rodents raised in a sterile environment without gut flora need to eat 30% more calories. They are also able to repress pathogenic bacteria from colonizing the gut through a “barrier” effect. They help prevent allergies. They’re even able to help prevent cancers.

It’s interesting that we’ve been able to selectively allow bacteria to colonize our bodies – and it’s not just us mammals; certain ants have gut flora that allow them to obtain nutrition from honeydew. In fact, the reason that ants are able to be herbivores at all is due to their intestinal flora. Completely unrelated herbivorous ants have bacteria from the same order – as Myrmecos puts it, “The bacteria are not mere evolutionary hitchhikers passively tracking the genealogy. They show up in a highly non-random fashion in ants that have need of nitrogen.” But it gets even more interesting! Leafcutter ants not only employ antibiotics in their fungus gardens, they use colonies of the bacteria Klebsiella to capture atmospheric nitrogen and make it available to the fungus and the ants. I wonder how similar the evolutionary symbiosis of these bacteria is?

And now, here are a few of our friendly flora.


Why we’re exactly the same, most of the time

Here’s a video of Robert Sapolsky, who has excellent hair. He gives an excellent overview of what is unique and what is different about humanity versus the rest of the animal kingdom. You’ll learn a lot about primate culture. It really is worth the watch (though start 5 minutes in; I can’t seem to embed it with that set). Here’s some other, possibly unrelated, things I learned:

  • Menstruation cycle matching – the dominant, most social female leads in humans
  • Chess grandmasters burns ~6000-7000 calories a day thinking
  • Vampire bats live in large social groups and search for cows blood in order to feed their communal offspring. If you prevent one from feeding other babies but make the bat look like it has blood, the other bats won’t feed her babies…evidence of tit for tat behavior
  • Highest entropy tasks release the most dopamine…tasks with the same amount of entropy (ie, 25% vs. 75% probability decision tasks) lead to release of the same amount of dopamine (I should find this citation…)

Monkey talk

Those crafty scientists at the University of St Andrews have managed to decipher monkey language, it seems:

“Krak” is a call that warns of leopards in the vicinity. The monkeys gave it in response to real leopards and to model leopards or leopard growls broadcast by the researchers. The monkeys can vary the call by adding the suffix “-oo”: “krak-oo” seems to be a general word for predator, but one given in a special context — when monkeys hear but do not see a predator, or when they hear the alarm calls of another species known as the Diana monkey.

The “boom-boom” call invites other monkeys to come toward the male making the sound. Two booms can be combined with a series of “krak-oos,” with a meaning entirely different to that of either of its components. “Boom boom krak-oo krak-oo krak-oo” is the monkey’s version of “Timber!” — it warns of falling trees.

This seems to be based on this PLoS One paper from November. They basically correlated vocalizations with features of the environment (ok, they used a GLM). They then used these features, such as the presence of a jaguar, as templates and simulated their arrival in the environment to check their predictions. They were right. The important point isn’t that the monkeys have words, but rather that they string together words to modify meaning (ie, they use syntax). Here’s how they sum it up:

[I]t is still largely unclear whether non-human primates intentionally inform their audience about the event they have just experienced, or whether their vocal response is more directly driven by the psychological processes triggered by external events, the currently prevailing hypothesis. What our results show is that callers appear to make some judgements about the nature of the event (tree fall, group gathering to travel, conspecific intruder, eagle, leopard), and that this assessment determines whether or not affixation takes place. Equally important, male Campbell’s monkeys rarely produce single calls but almost always give sequences of different call types.

I just want to know when we can hold a conversation with them that contains more content than an interview Sarah Palin. Zing!

The Matrix: Population you

Remember how the robots in the matrix harvested people for energy? Well – why not do that ourselves? Apparently, turning our bodies into portable batteries isn’t that far-fetched of an idea:

[T]he bio-batteries closest to reality at this time, the yeast cell ones, have a major problem with waste products. That waste is created as those particular batteries involve microbial yeast-based fuel cells that steal “some of the electrons produced when the yeast metabolizes glucose” in order to create a small current. While the entire process works just fine, the yeast cells are at risk unless the waste products are removed. We can’t exactly let the waste be dumped into the blood stream, so until there’s a some kind of cleaning process, the batteries are trouble as they either they die off or poison your bloodstream while trying to survive.

People are already dreaming up gadgets that could, say, use your blood to power a digital tattoo. Who needs an iPhone when you’ve got a blood powered tattoo on your arm?

Anyway, this is from a cool blog I haven’t seen before – This Cyborg Life. Read up on people choosing to amputate in order to receive prosthetics (sometimes there’s a good reason).

The Lyrebird

The lyrebird mimics sounds it hears in the environment in order to attract mates, combining the sounds in intricate ways. But it copies any sound it hears – including such things as chainsaws and camera clicks and whirs. Watch the video, it’s pretty impressive.

Dance, sifaka, dance!

I learned today that there is a lemur, the Sifaka, that dances, only to then learn that that’s not true. Apparently they just can’t walk on the ground very well, so they hop around sideways in what looks like a ‘dance’. What a sad day. Watch some videos of Sifaka Dancing, or just be informed by the video above.

Plants: they work!


Here’s a good blog called Howplantswork that focuses on, well, how plants work. It’s only updated once a month or so, but going through old posts is fascinating. Some highlights:

  • Plant versus plant: some plants kill other plants using natural herbicides
  • Nervous plants? (part 2) [ie, do plants have a nervous system?
  • Flowers: what you see versus what the bees see ]
  • Plant “RAM”? – some plants could record environmental experiences for future reference by altering their DNA
  • The World-Wide-Web: Are plants inter-connected by a subterranean fungal network?