Complex Systems Discussion Group

 Forgot Password
 Register now

QQ登录

只需一步,快速开始

Search
12Next
Return to List Add thread
View: 8454|Reply: 22

[Challenge Topic] How to grow a yeast cell as large as a grape (Xili Liu)

  [Copy Link]

3

Threads

13

Posts

115

Credits

Registered member


IP  220.181.149.208

Posted at 2012-5-21 23:33:34 | All floors |Read mode
Chanllenge statement:
How to grow a yeast cell as large as a grape?


Background
That size is an important attribute ofcells seems self-evident. It varies over enormous range. As unicellulareukaryotic organisms, the diameter of budding yeast is 3um, while thediameter of Xenophyophores, which is the largest single-cell organism,can be as large as 20cm. There is no debate that size is optimized byevolution. Different size is adapted to different habitat. But what are thebenefits and costs of being certain size? There must be some physical limits (surfacevolume ratio, diffusion rate, resistance to pressure, etc.) and biologicalconstraints (genome size, response to stress, metabolic efficiency, etc.).After all, what make cell this size?
It’s critical to have a sizer for populationsize homeostasis. But little is known about how cell measure its own size. Itmust be involved with feedbacks between cell size, growth rate and celldivision. Generally speaking, size control is at the late G1 phase, Startcheckpoint in budding yeast and restriction point in metazoan. Cell keepsgrowing during G1 phase until reaches certain size, cell passes Start checkpointand commits to division cycle. But how does cell detect its size and growthrate at Start checkpoint? We barely know anything about it.
From the first question, we see all thedeterminants about size. From the second question, we see how to maintain thestability of a given size distribution. Taken together, Can we engineer cellsize by evolution or synthetic biology? Most likely, cell size and division ratecan be tuned by G1 duration. People know many things about cell cycle controland TOR pathway which directly monitors energy level, however, the knowledgeabout the coupling between them and their correlation with cell size is verylimited. Can we try filling the gaps by theory?

Big Questions:
Try answering three questions:
1.What decide our current size?
2.How can cell know its own size?
3.How to manipulate size?


Main Methods:
in silico-evolution and experimental design.

Anticipated outcomes:
understand more on the evolution constrains of size control.


4 days’ schedule
Day 1:
Introduction about size control, cell cycleand cell growth.
Brain storming about the three mainquestions.
Divide into two subgroups, each work on onequestion of the first two questions.
Sleep on ideas and do more homework aboutliterature.

Day 2:
Vote on ideas and define doable projects (twosubgroups together).
Introduce possible tools: matlab and in-silicoevolution
Start working on the projects

Day 3:
Run programs, deduce mathematical equations,search for more literature, design experiments…

Day 4:
Organize results.
Combine the results of the two subgroups toget a whole picture of size control.
Suggest a possible way to grow a yeast cellas large as a grape.
Report.

Suggested Reading:
Alberts,B., Johnson, A., Lewis, J., Raff, M., Roberts, K., & Walter, P. (2008). Molecularbiology of the cell. Garland Science, Taylor & Francis Group. Chapter17 control of cell division and cell growth.
Jorgensen,P., & Tyers, M. (2004). How cells coordinate growth and division. Currentbiology : CB, 14(23), R1014-27. doi:10.1016/j.cub.2004.11.027
Morgan,D. (2007). The cell cycle: principles of control. Oxford UnivesityPress. Chapter 10.
Umen,J. G. (2005). The elusive sizer. Current opinion in cell biology, 17(4),435-41. doi:10.1016/j.ceb.2005.06.001

43

Threads

186

Posts

524

Credits

Moderator


IP  162.105.23.162

Posted at 2012-5-22 10:29:06 | All floors
Great! Thanks tuzi !
I'm very interested in that whether there are multi-cell organisms that build on the 20cm diameter cells~
给我一块二向箔,清理用

3

Threads

27

Posts

107

Credits

Registered member


IP  162.105.248.40

Posted at 2012-5-23 10:19:49 | All floors
There is a fiction of Liu Cixin mentioned "宏原子“. Maybe we will develop ”宏生命“……

1

Threads

9

Posts

44

Credits

Newbie Member


IP  219.221.192.143

Posted at 2012-5-24 05:12:30 | All floors
There is a fiction of Liu Cixin mentioned "宏原子“. Maybe we will develop ”宏生命“…… ...
Fleo replied at 2012-5-23 10:19
lol...this reminds me of another science fiction, ^_^ that carbon based organisms are very hard to build up in size comparing to silicon based organism. Carbon based molecules are more water soluble and CO2 produced as waste of metabolism is simply gas, but silicon based molecules are harder and more like watephobias and metabolised SiO2, hoho......thats why it would look like a crystal-like life form and could be HUGE.

1

Threads

9

Posts

44

Credits

Newbie Member


IP  219.221.192.143

Posted at 2012-5-24 05:15:52 | All floors
Is it possible to build a bigger cell with "stronger" internal skeletons?

1

Threads

11

Posts

61

Credits

Registered member


IP  162.105.160.21

Posted at 2012-5-26 23:41:03 | All floors
i'm very interested in this topic~
Maybe cell-cell interactions or 'communications' also play a role in determining individual cell size.

1

Threads

14

Posts

124

Credits

Registered member


IP  162.105.100.105

Posted at 2012-5-28 13:03:28 | All floors
Reply zhiyuanli Add Thread


    How many cells a multi-cell organism must have? Maybe if multi-cell organisms build on the 20cm diameter cells, it will take a long time to pass the information from one cell to another and it is difficult for the organisms to coordinate different parts of the body. Multi-cell organisms that build on 20cm diameter cells may sound amazing and horrible...

1

Threads

14

Posts

124

Credits

Registered member


IP  162.105.100.105

Posted at 2012-5-28 13:12:24 | All floors
Xenophyophores, the giant unicellular organisms, can be as large as 20cm, and they live in deap ocean. The water pressures are different between the top of the cell and the bottom of the cell, and do the water pressure have influences on the cell? Do they have mechanism that can balance the the difference of water pressure between the top and the bottom of the cell.

1

Threads

14

Posts

124

Credits

Registered member


IP  162.105.100.105

Posted at 2012-5-28 13:16:51 | All floors
Reply Haoxu Add Thread


    Maybe the cell size is related to the elementary elements which consist of the lives like the carbon or silicon,although the silicon lives have not been found yet...

1

Threads

14

Posts

124

Credits

Registered member


IP  162.105.100.105

Posted at 2012-5-28 13:27:02 | All floors
Maybe many pathways are related to the cell size control, ( I know little about the cell cycle and the  pathways related to the size control, maybe some of my opinions are too simple and naive,welcome to correct me.) and how do we choose some of them? And the experiment or the program we design may be simple compared to the reality, how can we evaluate our results from programs in the four days?

0

Threads

2

Posts

13

Credits

Newbie Member


IP  202.66.131.115

Posted at 2012-6-2 16:12:00 | All floors
we can fuse dozens of cell to a huge cell and to see what happens.

6

Threads

34

Posts

125

Credits

Registered member


IP  115.25.240.160

Posted at 2012-6-2 21:59:24 | All floors
Reply lyxiong Add Thread


    I do not think this has something to do withinformation transportation. As far as I know, with certain structure like plasmodesma or certain chemical things likehormone biological information could pass efficiently within both plants,animals and microorganism. The major limit, in my opinion, is that huge sizewould prevent cells with more active pocess of interchange of material.

6

Threads

34

Posts

125

Credits

Registered member


IP  115.25.240.160

Posted at 2012-6-2 22:06:15 | All floors
Reply Haoxu Add Thread


    I think it is a good idea. It is said that the cellsare supported by a special skeleton called cytoskeleton consisting ofmicrotublue and microfilament which made ofactin. Cytoskeleton is also in charge of transportation, with advanced engineeringmethod we could design stronger protein to support the cell, then we would beable to overcome the disadvantages against larger cells.

6

Threads

34

Posts

125

Credits

Registered member


IP  115.25.240.160

Posted at 2012-6-2 22:12:44 | All floors
Reply MaXiaopeng Add Thread


    I do not think it would work. First of all, the largermix-up cell would have trouble in things exchanging process with outsideenvironment, for larger cells have smaller specificsurface area. Secondly,too much organelle would have negative effects on cells; Besides, it would havelittle chances a cell could work efficiently with many nucleus.

6

Threads

34

Posts

125

Credits

Registered member


IP  115.25.240.160

Posted at 2012-6-2 22:21:04 | All floors
My suggestion is that we could chemical reagent like colchicine to interrupt cell division process. In the mean time, we could remove the redundant things in cell with biological technique. Then we could get cell we wanted. I am willing to hear your comments.

1

Threads

11

Posts

113

Credits

Registered member


IP  218.199.160.148

Posted at 2012-6-3 00:02:39 | All floors
Reply xili.liu Add Thread

I'm very interested in this topic. There is a review about cell size control in yeast recently, some new discoveries were included, you may add it to your suggested readings?

Jonathan J. Turner, Jennifer C. Ewald, Jan M. Skotheim(2012).Cell Size Control in Yeast. Current Biology[url]http://dx.doi.org/10.1016/j.cub.2012.02.041[/url]

1

Threads

11

Posts

113

Credits

Registered member


IP  218.199.160.148

Posted at 2012-6-3 00:26:55 | All floors
Now that cell size exhibit fluctuations, we know that the fluctuations will not enlarge between generations may because it is controlled on checkpoint. How about pseudo-mimicing or trying to skip  the size checkpoint and selecting larger cells generation by generation, like strategies in plant breeding?  We may be able to hypothesize enlargement between generations will decrease, Can we deduce the maximal size in this way theoritically when we measure the enlargement for a limited number of generations?

6

Threads

34

Posts

125

Credits

Registered member


IP  115.25.240.160

Posted at 2012-6-3 19:57:54 | All floors
Reply ShangtongLIi Add Thread


   
I do not think we would have enough time to grow yeastgeneration by generation to see its size limit. However, I agreed that we couldpredict the largest size of a yeast cell. Maybe we could use some knowledge in mathematicalmodeling to calculate the limit. At the limit point the whole surface of thecell would exactly satisfied the need of interchange of things between cell andenvironment.

6

Threads

34

Posts

125

Credits

Registered member


IP  115.25.240.160

Posted at 2012-6-3 20:03:13 | All floors
By comparing the difference between larger cells and smaller cells, maybe we would find something (both in genetic level or cellular level). We could use statistical method by using crosstabs analysis (comparing size and factors) to see if these difference is related to size control. Then we will design a cell large enough.

3

Threads

9

Posts

32

Credits

Newbie Member


IP  162.105.38.137

Posted at 2012-6-8 15:29:13 | All floors
I think we can also solve this problem in genetic view. If we actually produce  larger cell, then the cell should needs more proteins. So the frequency of transcription will be so high that the stability of genes can not be protected.
You need to log in before you can reply Login | Register now

This forum Credits Rules

Mobile ver.|Darkroom|Complex Systems Discussion Group

GMT+8, 2018-1-21 20:47 , Processed in 0.087117 second(s), 22 queries .

Powered by Discuz! X3 English ver.

© 2001-2013 Comsenz Inc.

Quick Reply Back to top Back to list