Julie Theriot (Stanford, HHMI) 2: Mechanics and Dynamics of Rapid Cell Motility

[@smithsonian2516]

is she the best teacher on the subject ever

[@rickfearn3663]

Incredibly exciting work, Dr. Theriot!!! Your presentation is like participating in a detective movie where we are trying to discover how and why the "movement" took place. This is a movie that you can't afford to miss! Thanks.

[@essentialsofbiology1643]

God Bless You Julie Theriot! And Thanks KZbin for allowing the videos to be played at 0.75 speed.

[@xingchenghuang7609]

Figuring out the mechanism of cell mobility could be the start of a major breakthrough for the next industrial revolution led by biology! Super amazing research builds up the foundation for revealing secrets of life miracles!

[@geezerdombroadcast]

Lots of challenge, lots of fun. I feel like I was just shot with a fire hose of knowledge. Thanks Julie. You rock. Love your wild speculations.

[@dannichols6261]

What wonderful *detail* ! And *accurate* 'closed-captions', too! And the movies of the cells! So very well done Julie Theriot!

[@luisrueda6109]

Very enjoyable presentation.

[@ColinDdd]

so awesome seeing the complex neutrophil movement

[@user-ir4gh3wy3l]

This was literally so cool

[@johnterry6541]

She can talk well! For such a hard topic

[@IshanPandit]

1:19 Actin as a Nanomachine Actin at Leading edge, rear edge 3:48 Model System Keratinocytes from Fish Scales 6:26 Fluorescent labelling of Actin and Myosin 7:10 Cycles of Actin based Cell motility 13:26 Adhesion strength affects how cells move (see S. Sen work) 18:48 Myosin chops up actin at rear poles 33:16 Neutrophil turning & Myosin asymmetry - "Steering wheel"?

[@ZdrytchX]

The high-adhesion made me think of a guy with like 5 hyperactive dogs on a spring loaded leash that just run off for like 10 metres then get tired and as it gets dragged back to the owner, the owner gets tugged forward, then the dog runs off again.

[@victorianunezbaron1536]

This is so wonderful, thanks for the explanation.

[@stevebutrimas9972]

It is so interactive and complex it might be helpful if you spoke with a focus on information transfer and information interdependencies.

[@russ1618]

Thank you for this presentation. It seems likely to me that the accumulation of myosin at the back of the cell may be driven directly by the actin network; if the actin polymerization is triggered by environmental cues over some region of the cell membrane, then myosin need only collect at the antipode, which will happen naturally by the sweeping action of the actin network. How does the cell membrane move in this kind of motility? In order for the cell to extend, I would assume that the membrane would also have to be extended, and then be recycled at the rear of the cell, along with the anchor sites, yes?

[@reinerwilhelms-tricarico344]

This is amazing stuff. I have a question regarding the motility of even those cut up lamellipodium cells, not really a cell any more, without a nucleus and probably a lot more missing (at about 9:00 min into the presentation): How do they sustain this process from a merely energy flow of view? Somehow they must be able to regenerate enough ATP everywhere to keep the assembly of actin in the front going. It is like an active transport flow. It requires a distributed energy supply and somehow entropy must be exported. Without that it looks like a miracle to me :-)

[@Vir9il]

I'm not a biologist, but I assume that without mitochondria to regenerate ATP (and without a food source like glucose), the lamellipodium fragments soon run out of energy and stop. It's not a perpetual motion machine.

[@thisnicklldo]

I feel the need to explain a bit more what I meant - not sure why, other than that is a very interesting business. If for keratocytes I call the 'axis' a central line from front-to-back; and if, as a very simplified model, I assume 2 anchor sites on the base of the keratocyte, symmetrically placed either side of that axis, and towards the back of the keratocyte (perhaps 2/3 of the axial length, or whatever). Then to turn left, it is only necessary to place the right-hand anchor site fractionally assymetrically further to the right. Newton will accomplish all the rest: The keratocyte must turn, so long as the initial distribution of actin stays axially symmetric - the front of the actin will be pushed, by Newton, to the left, and the rear, with the Myosin, to the right - which is what you observe.

[@chandanpaswan3728]

Good teachig

[@thisnicklldo]

Fascinating. I am still a little puzzled by the simple Newtonian dynamics. If the force is exerted by expanding Actin at the front, then the equal and opposite reaction must be at the anchor sites. If I were looking to design a system like that, that could turn, I would regulate the placement of the anchor sites. The placement of these must anyway surely be as important ( equally and oppositely important!) as the dynamics of the front. That is, it's all very well just evaporating the Actin at the back, but not if the force between the intact front and anchor site is destroyed. Perhaps anchor site placement and control is not discussed because it is experimentally difficult to follow? Of course I may be getting the wrong end of the stick - I knew nothing at all about this subject until viewing these videos. Anyway, even if you are disappointed that your viewers are so stupid, at least console yourself that you have made them very interested.

[@priyanshujharwal5727]

It is the world of low reynolds number for these, i guess.

[@santirodriguez7692]

Lamento no poder escuchar la clase en español!

[@HanadiH]

I understand that thinking of biology in mechanistic terms helps us wrap our heads around all the dynamic processes that exist within us and other life forms, but cells are not machines and we're not machines. And that's what's so amazing. Feel free to use metaphors to enhance understanding, but don't call them machines.

[@imagination7710]

Definition of a machine: 'an apparatus using mechanical power and having several parts, each with a definite function and together performing a particular task'.

[@myperspective5091]

This was interesting. 👍😊👍

[@peters972]

Is the cell drawn towards a chemical or something? How does it know what direction to go in? Or does it just GO, lol?

[@ImprovingAbility]

8:05 I wonder if this already vivisection or not 😆😅 poor little fellas trying to heal the skin but their fish is already far away and they don't know yet that they are doomed ... great presentation btw!

[@samgrainger1554]

Do you think they respond to electrical currents because electrical signals have a use in regeneration of the wound when a scale is removed?

[@samgrainger1554]

Or just as a vunerability/side effect of the way it works

[@stevebutrimas9972]

Motility is code for mobility?

[@UmmUmarHamzah]

UPR-RP Solamente hasta el minuto - 20:12.2

[@YouTubist666]

4:23 No animals were harmed during the undertaking of this research.

[@zu3035]

excuse me Madam. I want to contact you, if you have any contact source then give me, will be thankful.

[@rogerscottcathey]

someday we'll have yachts with no need for sails.

[@myperspective5091]

These cells remind me of those Water Wiggle toys, sometimes called Water Wiggle Snakes or just Water Tubes.

[@robertecarpenter]

Let's see now. I am supposed to believe that this phantasmagorical complexity arose by mutations in the chromosomal instructional data base of the imaginary first self-replicating organism? To believe that requires religious zealous faith. Start with the instruction book for building a bicycle. Cut it, splice it, dice it, damage it, and thereby turn it into the instruction book for building a Boeing 747. And while the instructions are "evolving" the machinery in the cell that the they control have to "evolve" with it. That's a preposterous supposition.

[@mariacarolinagallegoiradi5466]

Great explanation. Thank you for sharing it.

[@ColinDdd]

@@mariacarolinagallegoiradi5466 thats not an explanation, its someone who doesn't believe in evolution

[@IshanPandit]

1:19 Actin as a Nanomachine Actin at Leading edge, rear edge 3:48 Model System Keratinocytes from Fish Scales 6:26 Fluorescent labelling of Actin and Myosin 7:10 Cycles of Actin based Cell motility 13:26 Adhesion strength affects how cells move (see S. Sen work) 18:48 Myosin chops up actin at rear poles 33:16 Neutrophil turning & Myosin asymmetry - "Steering wheel"?

[@boy-sb4ef]

roop mallik ka victim