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Author: xili.liu

[Challenge Topic] exclusive size control mechanism

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Posted at 2012-5-5 22:13:58 | All floors
Edited by QX_Cai at 2012-5-5 22:15

Reply xili.liu Add Thread

Is cln3 the master regulon of cell size?  If these fat cells are cultured for a long period of time, for exaple several hundred of generation, what change will happen inside the cells?  Will they evolve to another steady state?

   

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Posted at 2012-5-5 23:49:07 | All floors
Reply xili.liu Add Thread


   Really? That's very interesting. I guess they didn't reach the size limit you mentioned about nutrient uptake.
   Is that possible that cell that is too big is more easily eaten by predators? Fat worm meets the bird.
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Posted at 2012-5-6 10:11:59 | All floors
Reply zhiyuanli Add Thread

There used to be a explanation about why a single cell cannot grow too large. The metabolic ratio depends on the volume, and nutrition taking depends on the surface area of the cell. That is to say, a bigger cell is less able to grow as fast as a wild type cell. But is there any optimization in this homeostasis, perhaps an interesting question.   

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Posted at 2012-5-11 09:58:17 | All floors
Reply QX_Cai Add Thread


   im wondering if this cell could devide without cln3. if it could, after a long time of culturing and evolving, the offsprings might become smaller because it takes too long to grow into a fat cell and the efficiency of reproduction is low, i suppose.
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Posted at 2012-5-11 10:23:06 | All floors
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interesting~what's the "bird" for  yeast? c elegans or something?
  is it possible that a cell doesnt grow too large just because it is time consuming? according to xili, lowed surface/volume and nuclear/cytoplasma ratio doesnt cause any defect within such a wide range (from 1 to 100 times WT size), can we draw the conclusion that cell cycle length contributes to fitness much more than cell size when the cell is not too large (not large enough to reach the limit for nutrient uptake), and that the cell cannot "sense" or control its volume and it just controls its cell cycle length to reach a higher growth rate, and cell size is just a "passive result"?
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 Author| Posted at 2012-5-11 12:29:11 | All floors
Reply Amber.Zw.W Add Thread

Cells cannot divide without cln3. They simply  cannot enter cell cycle.
   

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Posted at 2012-5-12 20:01:19 | All floors
Reply xili.liu Add Thread


    so the cute fat cell is just a result of growing for a long time.
does it mean that cells just controls its cell cycle length instead of somehow "sensing" its size,
and that the size is simply a result?
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Posted at 2012-5-16 10:24:41 | All floors
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In my opinion, for individual the bigger one is more competetive. When take populaton into account, the bigger one spends more resources for bodily gorwth but not reproduce. The smaller one might be more fit.   

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Posted at 2012-5-14 21:24:39 | All floors
Reply ZhengXu Add Thread


    but the final fitness depends on the number of viable offspring one individual finally gives out...
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Posted at 2012-5-19 18:08:01 | All floors
so one specific question is, as suggested by xili: theoretically, what's the possible mechanisms that are able to maintain a size homeostasis? and why the yeast choose the current one?
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Posted at 2012-5-19 18:18:27 | All floors
Another question can be : from yeast to whale, the volume of the organism changes for several orders of scale, but the cell size is almost in the same scale. There are some optimization of the cell, so what's the goal of optimization? For the single cell organism, what determines the difference in size?
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Posted at 2012-5-20 12:58:10 | All floors
Maximal known single-cell organism ( 这是什么怪物呀……)
http://en.wikipedia.org/wiki/Xenophyophore

Xenophyophores are giant unicellular organisms found throughout the world's oceans, at depths of up to 10,641 meters (6.6 miles).[1] Xenophyophores are found in the greatest numbers on the abyssal plains of the deep ocean. They were first described as sponges in 1889, then as testate amoeboids, and later as their own phylum of Protista. A recent genetic study suggested that the xenophyophores are a specialized group of Foraminifera. There are approximately 42 recognized species in 13 genera and 2 orders; one of which, Syringammina fragilissima, is among the largest known protozoans at a maximum 20 centimetres in diameter.
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Posted at 2012-5-23 10:28:59 | All floors
an interesting topic! I think it's likely to have something to do with telomerase.

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Posted at 2012-5-28 22:53:41 | All floors
Reply Lulin Add Thread

usually, telemere has to do with the maximal times one cell can divide. However it mainly has to do with multi-cell organisms especially mammalians. For yeast, they have ways to maintain a constant length of telemere.
   
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