Gliding Diatoms

They twist, they turn… they glide!!

But you ask, what am I talking about here? It’s not Michael Jackson on his moon walk, but it’s no less impressive. I am talking about our dear friends – diatoms – unicellular algae that prefer to live in a glass house. It’s no originate glass house; it’s a spectacular glass house that we don’t really know how they know how to make.. You get the point. 

You might imagine if you were trapped inside a tiny little glass house (which is stiff and rigid); you could not move with that entire glass house. But that is what diatoms do – they glide and adhere to surfaces. And the best part, it’s still a mystery how this actually glide on any surface, pretty much like a moon walk. 

Here are the videos of diatoms performing a moon walk: 

Methods: 

1. Go to a pond and pick some pond scum. Anywhere you see a little greenish growth is good enough. 

2. Put this “not so pretty” looking stuff on a glass slide and mount a cover slip on top. Since you want to keep some water in the slide, you can seal the slide with nail polish or just some tape. 

3. Mount this inside your Foldscope (140X; low mag) and get ready for some fascinating glass structures that still move. 

4. I recorded these videos with my iPhone 5 with my magnetic couplers. 

You will see multiple diatoms gliding in the videos above. They mostly move in straight lines but suddenly change directions. That’s puzzling; what drives the directionality to begin with and how can they change. They don’t have a head or a tail; so spontaneous symmetry breaking and reversal is fascinating to watch. Are they detecting anything in the environment? 

What we know is that the motility is caused by actin-myosin complex. It’s been demonstrated that drugs that inhibit both actin filaments or myosin motors will inhibit mobility; and the mobility can be restored back in 5 seconds by removing the drugs. 

For more info on drug pertibations http://www.ncbi.nlm.nih.gov/m/pubmed/10470016/

But that’s not enough to explain how on earth is something that lives inside a glass she’ll capable of gliding along. 

Cheers 

Manu 

8 Comments Add yours

  1. Is the spinning ball a volvox, or a crazy fast diatom? Can’t wait to look more closely at our pond water and find some diatoms.

  2. Manu Prakash says:

    @Honan: the spinning green object is another algae; but not a volvox. It’s a single cell. At this magnification; volvox would be very big. I am trying to ID all the algae I filmed. I think I have almost 10ish species in the same sample so far.

    If you take any pond water; it would be shocking if you don’t find diatoms. Both ocean and freshwater samples.

    Will wait for your post 🙂

    Cheers
    Manu

  3. jeneel says:

    @manu this can help u find the species https://diatom.ansp.org/algae_image/SearchCriteria.aspx . this database is really useful. i guess it has all the diatoms. I love the needle one. why didn’t the needle one and the round one collide? it seemed that it passed through it. why didn’t the ball hit the bat? 🙂

    -JPK

  4. Manu Prakash says:

    @JPK: what a great resource you pointed out. I had so much fun browsing the same. In my next post; I will write down the identifications to the best of my ability. Thanks for that wonderful link..

    On collisions; gliding motility (which can also be found in other species including bacteria) only works when the object is extremely close to a substrate. Thus it seems that the objects can be in the focal plane (and hence both in focus) and still miss the collision 🙂 after watching the World Cup final last night; I am seeing bat and ball in this video.

    Cheers
    Manu

  5. Niramay Gogate says:

    Great!! extremely great!!
    Can you try out such videos with cross polarization or darkfield microscopy?
    You see, the diatoms in both the videos occupied very less portion of total field of view. So if you use darkfield; only the diatoms will be enlighted.

  6. Niramay Gogate says:

    @jeneel
    I visited the site that you suggested to Manu. I don’t know much about diatoms but images on that website were just great and I too feel that it has covered almost all the diatoms on earth.

  7. jeneel says:

    I see a collision in the 1st video on the top right corner it collides once then comes back again for one more ….. seems to be its enjoying that 🙂

  8. laksiyer says:

    Gliding motility is a fascinating subject and I love the military gait of the diatom while the ciliate almost jumps around in circles.

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