Cytoplasmic streaming in a large Desmid

Cactusdave · Post by **Cactusdave** » Tue Mar 01, 2016 8:37 am

The active continuous streaming of cell cytoplasmic contents is a well known phenomenon, particularly well observed in some plant species. It has be well shown in mosses and Elodea for example http://www.howplantswork.com/2010/04/25 ... g-the-sun/ . A recent scientific paper on the subject gives this summary of what is known about how it works.

Many cells exhibit large-scale active circulation of their entire fluid contents, a process termed cytoplasmic streaming. This phenomenon is particularly prevalent in plant cells, often presenting strikingly regimented flow patterns. The driving mechanism in such cells is known: myosin-coated organelles entrain cytoplasm as they process along actin filament bundles fixed at the periphery. Still unknown, however, is the developmental process that constructs the well-ordered actin configurations required for coherent cell-scale flow.

http://www.pnas.org/content/110/35/14132.full

I saw it working very nicely in this large desmid (Closterium sp. ?) and made a short video clip to illustrate it. Nikon Diaphot with DIC. Nikon X40, 0.65 Plan DIC objective, Canon 5DMk2 camera. Magnification on sensor X100. Blue fringing is rather noticeable on out of focus edges, presumably as this lens is only an achromat.

https://vimeo.com/157293409

I'm not sure what the busy little flagellates that keep the desmid company are. They move in a rather amusingly haphazard way.

carlos.uruguay · Post by **carlos.uruguay** » Tue Mar 01, 2016 11:57 am

Very nice!!!!!

Bernd · Post by **Bernd** » Tue Mar 01, 2016 12:36 pm

My guess is that the little flagellates actually are zoospores of a parasitic chytrid fungus. The way they move is quite characteristic.

Bernd

billporter1456 · Post by **billporter1456** » Tue Mar 01, 2016 2:34 pm

Very clear images of the streaming! Nice job.

Sumguy01 · Post by **Sumguy01** » Tue Mar 01, 2016 11:32 pm

Nice vid.
Thanks for sharing the info on streaming.

Cactusdave · Post by **Cactusdave** » Wed Mar 02, 2016 4:51 am

Thanks Carlos, Bill and Sumguy. That's interesting Bernd, I hadn't considered the possibility that the tiny flagellates were fungal zoospores. I have seen similar organisms frequently in algal cultures, often in large numbers.

Jacek · Post by **Jacek** » Wed Mar 02, 2016 8:34 am

nice

Cactusdave · Post by **Cactusdave** » Thu Mar 03, 2016 5:29 am

Thanks Jacek.

Charles Krebs · Post by **Charles Krebs** » Thu Mar 03, 2016 12:53 pm

Nice video. Your Diaphot/40X/Canon 5D make a good combination.

Cactusdave · Post by **Cactusdave** » Thu Mar 03, 2016 2:12 pm

Thanks Charles.