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Brews & Views Bulletin Board Service * Brews and Views Archive 2004 * January 26, 2004 * Yeast cycle termination => dell death? < Previous Next >

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Fredrik (62.20.8.148)
Posted on Monday, January 12, 2004 - 11:50 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I have a question, perhaps Chris Colby or someone else can help out?

As I understand the cell cycle, once the yeast has passed the "point of no return" of budding in during the stage G1, it bound to proceed to complete the budding cycle before allowed to either go off cycle, or initiate a new cycle.

But what if a cycle is terminated, by for example crash cooling? As I understand a cell in the process of budding is technically not able to go dormant? So would the budding cells be bound to die? Or is there a way for such cells to recover in a way not evident from the simple cell cycle?

/Fredrik
 

aquavitae (134.84.195.46)
Posted on Monday, January 12, 2004 - 12:53 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

After commitment to the proliferative cycle (START in yeast, the restriction point in mammalian cells), cells have many checkpoint controls that ensure proper growth, duplication of DNA, and division. Failure to properly execute temporal events will lead to cell cycle arrest until the problem is resolved; if it is not the cell will often apoptos (die). Temp changes are example of stress, which depending on severity and damage sustained will lead either to cell cycle arrest and subsequent recovery, or death.
 

Fredrik (62.20.8.148)
Posted on Monday, January 12, 2004 - 01:17 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Thanks aquavitae! Do you have any idea of how long as a ballpark, a cell my be in "arrested" before it has to recover in order not to die? I'd guess this arrest is in the same order of magnitude as the cell periodicity at most? And not extended periods like say 12 hours of more? Since off cycle is the "safe" idle, mode, so I'd assume there is a limit as to how long an arrest can durate before the cells dies?

Or what do you think?

/Fredrik
 

aquavitae (134.84.195.46)
Posted on Monday, January 12, 2004 - 01:38 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Dormany can last a long time (think dry yeast). Even in solution this period can be extensive (think yeast cake in fridge). In these situations, however, the yeast has really exited the cell cycle and sort of shut down operations. This is probably what happens in the case of "crash cooling"; ie the cells finish their proliferative cycle (which is not that long) and then exit beause conditions are not right for continued proliferation. Cell cycle arrest due to checkpoints is more likely to occur with things like rapid heat shock, DNA damage, chemical insult, etc. Even in these situations cell cycle arrest can last for many hours depending on extent of damage.

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