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Tuesday, February 16, 2010

Journal Club, Feb 19

The Biochemical Basis of an All-or-None Cell Fate Switch in Xenopus Oocytes

James E. Ferrell, Jr. and Eric M. Machleder
Posted by at

12 comments:

  1. funny brainFebruary 16, 2010 at 2:30 PM

    Niki Arinze

    Ferrell

    1. Levels of MAPK phosphorylation can be used to determine the response of indivdiual oocytes to progesterone
    2. What is the Hill coefficient? What determines if it is high or low; is it just relative to something else? What's an oocyte extract?
    3. A look at the "machinery" of Oocytes
    4.Why would things be different in an extract?
    3.

    ReplyDelete
  2. Tommy ByrdFebruary 17, 2010 at 10:39 PM

    Tommy Byrd
    Ferrell
    1. Xenopus oocyte MAPK response to progesterone or Mos causes a biological all-or-none fate switch to be activated in a positive feedback cascade
    2. What are some applications of this research? Why is xenopus such a good model organism for research?
    3. Cell cycle signaling cascades
    4. Does the all-or-none character of this fate-determining trigger play a role in human embryogenesis?

    ReplyDelete
  3. Amy OFebruary 18, 2010 at 3:00 AM

    Amy Ostrowski
    Ferrell

    1. Oocyte maturation in Xenopus is an all-or-none response to progesterone stemming from positive feedback and intrinsic ultrasensitivity of the MAPK cascade.

    2. Why is oxygen's binding to Hemoglobin the benchmark for the Hill coefficient? Don't molecules like carbon monoxide have a 200 times larger affinity for hemoglobin, rending oxygen's binding much weaker?

    Is the Michaelian system they are referring to similar to Michaelis-Menten kinetics of enzymes?

    3. Other possible examples of the all-or-none response in cells, apoptosis during develop perhaps?

    ReplyDelete
  4. LaurenFebruary 18, 2010 at 11:40 AM

    Lauren Kolski
    Ferrell
    1. The all-or-none biological response of oocytes to progesterone stems from the MAPK cascade and the positive feedback loop within which this cascade lies.
    2. What is steady state phosphorylation? What is the difference between oocyte extracts and intact oocytes? Can you go more in depth as to what a Hill coefficient is and how a Michaelian system relates to this?
    3. Application of this discovery. Fertility treatments?
    4. WONDERFUL journal article. I really enjoyed reading it. :-)

    ReplyDelete
  5. Liwei JiangFebruary 18, 2010 at 2:12 PM

    Liwei Jiang
    Ferrell

    1. MAPK cascade causes a switch-like behavior in the fate determination of Xenopus oocytes.
    2. Please explain the sentence "even if individual oocytes had perfectly switchlike responses, samples of oocytes would yield a graded response if the oocytes varied with respect to the concentration of progesterone required to switch them on."
    3. For comparison, can you give examples of other enzymes exhibiting highly cooperative binding and give their Hill coefficients?

    ReplyDelete
  6. HussainFebruary 18, 2010 at 5:11 PM

    Hussain Jinnah

    Ferrell

    1. The Xenopus oocyte MAPK cascade is an all-or-nothing response to progesterone involving phosphorlyation and positive feedback mechanisms.
    2. What's this Hill coefficient & how's it calculated?
    3. You could discuss cell cycle regulation in general, positive/negative feedback loops, etc.

    ReplyDelete
  7. Elizabeth LillieFebruary 18, 2010 at 8:26 PM

    Elizabeth

    Ferrell
    1. The MAPK phosphorlyation cascaed is responsible for an all or nothing resonse to the maturation of the Xenopus oocyte.
    2. Where does this information lead, what can become of this learned association.
    3. Other papers building off of this information

    ReplyDelete
  8. ericalcurtisFebruary 18, 2010 at 11:45 PM

    1. MAPK cascade and the positive feedback associated with it create a switch-like threshold at which an all-or-none response is triggered.

    2. What is steady-state phosphorylation? How is the Hill coefficient calculated?

    3. What other biological switches exhibit cascade ultrasensitivity and positive feedback? What practical applications result?

    ReplyDelete
  9. ParkerFebruary 19, 2010 at 12:03 AM

    Ferrell

    1. When Xenopus oocytes mature, an all-or-none MAPK cascade is triggered.
    2. So I see that this Xenopus thing is a frog, but what is an oocyte and why is its maturation important?
    3. Biology overload.

    ReplyDelete
  10. Ayeeshik KoleFebruary 19, 2010 at 12:40 AM

    Ayeeshik Kole
    Ferrell
    1. The MAPK cascade generates an all-or-none fate response in Xenopus oocyte.
    2. Has this type of fate switch been observed in other organisms?
    3. Positive feedback switches in other biological stystems

    ReplyDelete
  11. Chaitanya AllamneniFebruary 19, 2010 at 12:56 AM

    Chaitanya Allamneni

    Ferrell

    1. The MAPK cascade causes an all-or-nothing fate determination of xenopus oocytes after their exposure to progesterone.

    2. Could oocyte maturation and fate determination be studied in microdevices? Is it worth looking at?

    3. Other cell phosphorylation cascades, g-protein cascades, etc.

    ReplyDelete
  12. RosieFebruary 19, 2010 at 1:05 AM

    Rosie Korman
    Ferrell
    1. Exposure to progesterone causes Xenopus oocytes to mature. This maturation is "all of none" - the oocyte exists in either the premature or mature state, it is only in an intermediate state for a very short time.
    2. What is the threshold progesterone concentration for triggering this all or none response?
    What are the applications of this finding?
    3. The effect of progesterone on human oocyte maturation.
    4. Go Evan Lysacek, go USA!
    US - medals: 17.6% of total medals awarded. population: 4.5% of total world population.

    ReplyDelete

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