Don’t you just love to read stories that have words like: “In a stunning discovery that overturns decades of textbook teaching”?
I know I do.
I’d like to recount two recent discoveries that share a particular trait: really narrow tubes. Really, really narrow tubes.
It’s even better when these involve something that has been staring everyone in the face since forever … and it just takes one person noticing that thing that everyone else discounts or ignores.
First I’d like to recount my recent learning experiences with the human Brain and how it gets rid of it’s crap. Not talking bad thoughts here, nope, I’m talking the waste products of cellular activities. Chemicals created when cells work that have to be disposed of or things get all gummed up.
In most of the body that is done by a system of tubes that looks very much like the blood system. Except instead of blood it carries Lymph. The gray water of the billions of cells we call Me. And up until recently there was a big mystery about the lymphatic system in humans – there was none in the brain.
That’s correct, we could find one every place we looked in the human body except the brain. No one had ever seen one there. So it sat there, a mystery at the heart, er, brain, of medical science. I found out about this in a TED talk which I watched for the first time a few months ago. (Jeff Iliff: one more reason to get a good night s sleep)
In this talk Jeff Iliff talks about a discovery about how waste products are dealt with by the brain. During sleep the cells of the brain lose a little size and the gaps between them spread and the Cerebral Spinal Fluid can suffuse into the brain and flush these things out. No one knew this until recently and it solves that mystery. And it’s also showing a behavior of the organ, the brain, we were not aware of before.
And it’s wrong.
Or at least not the whole story.
Because that missing brain Lymphatic system? … someone found it. Antoine Louveau PhD. PostDoc fellow was the person and he had imaging help from Igor Smirnov. You can read more about it in this article: http://www.sciencedaily.com/releases/2015/06/150601122445.htm ( or here http://dx.doi.org/10.1038/nature14432)
Turns out the tubes in this lyphatic system are really, really small and right next to othe tubes that are quite large in comparison. It took some fancy imaging techniques to see them but there there all along. Hiding in plain sight.
The other discovery has to do with how cells communicate with each other.
How do they do that?
Do they physically touch and pass chemicals on to each other?
Do they emit chemicals into the environment and rely on these brushing up against another cell?
That last is kind of like broadcasting a shout out … What about if you want to have a private conversation?
Well it would appear that some Stem cells use really thin nanotubes to reach out and touch each other. ‘Wired’ instead of ‘Wireless’ communications.
Another Post Doc researcher, Mayu Inaba, saw these thread-like connections and asked her mentor about them. She went and looked at previous studies and found them there as well. But Mayu had asked what they were …
And what do these particular wires do?
Well in a previous blog post I mentioned how the chemistry in a cell’s environment can shape it’s behavior, which code in its DNA gets activated. In researching how split Stem cells in developing fruit flies can express differentiated development while coming from the same progenitor cells. Where does this identity come from if the cells are immersed in the same chemistry? It would appear to be via cell-to-cell tubes …
You can read about it here: http://dx.doi.org/10.1038/nature14602
Or in this article: https://www.google.com/url?q=http://www.sciencedaily.com/releases/2015/07/150701131958.htm&sa=U&ved=0CAUQFjAAahUKEwixusmLpJDHAhUKmYAKHZ6SDDU&client=internal-uds-cse&usg=AFQjCNFYLEEfL44fz39aX8wqFfmAT9lEdw
I kind of experienced this last week.
Friends from China were visiting and wanted to spend some time in a lake or stream. The first place was a small stream just after it passed under a bridge. We’d been in the water for a while and then I saw something move on the bottom. It turned out that there were not only the expected minnows but also a number of crustacean like creatures which we figured out to be dragon-fly nymphs. I was seeing them them for around 5 or 10 minutes before I actually noticed their presence.
The more we looked the more we saw. A turtle, a garter snake and a horse-hair snake were a few of our other ‘discoveries’. If we had not noticed the horse hair snake in motion we’d have never given it a second thought.