Transcript Evolution of Apoptosis

Evolution of Apoptosis
By Sean A. McMillan
What is Apoptosis?
• Programmed cell death (PCD)
• Several kinds
– Caspase dependent
– Caspase independent
• Ex: high amounts of Ca+ can initiate apoptosis
• Caspases are proteases that play key roles in
apoptosis
• Was believed to be only a multicellular trait
Purpose of apoptosis
• Mitosis checkpoints
• Apoptosis will be
triggered to prevent
cells from becoming
cancers and harming
the body
Purpose continued
• Apoptosis purpose is to prevent a defective
cell from multiplying and creating more cells
with its implication
What is Apoptosis?
• Programmed cell death (PCD)
• Several kinds
– Caspase dependent
– Caspase independent
• Ex: high amounts of Ca+ can initiate apoptosis
• Caspases are proteases that play key roles in
apoptosis
• Was believed to be only a multicellular trait
evolution
• Maria segovia et al.
• Did research into apoptosis in higher
metazoans and in unicellular organism
Dunaliella tertiolecta
• 5 day experiment
• Observed Dunaliella tertiolecta in a light
deprived state
Dunaliella tertiolecta
• Unicellular organism
that derives its energy
through light
• Segovia set up an
experiment to see if in
the absence of light
Dunaliella tertiolecta
experienced apoptosis
Results
• At the end of the 5 day
period Dunaliella
tertiolecta had lost all
color
• Chromatin
condensation
• Nuclear membrane
degradation
• DNA fragmention
Results
• Dunaliella tertiolecta
did in fact show signs of
apoptosis
Western blot
• Ran the extracts of
Dunaliella tertiolecta
whole proteins with
antibodys to human
caspases
• Caspases are very
specific proteases
discussion
• Family of caspases
predates multicellur
organisms.
• Viral infection from
unicellular organisms
could have transferred
both machinery and
pathway into
eukaryotes
Apoptosis
• Frank medeo
• Also found evidence of caspase like activity in
unicellar organisms
• yeast
Further research
• More research into mechanisms and
machinery
• Better understanding could help treat cancer
• Clearer understanding of human evolution
Works Cited
•
•
Maria Segovia, Liti Haramaty, John A. Berges, and Paul G. Falkowski. 2003
Plant Physiology. Cell Death in the Unicellular Chlorophyte Dunaliella
tertiolecta. A Hypothesis on the Evolution of Apoptosis in Higher Plants
and Metazoans, plant physiology. Volume 32,Pg. 99-105
Madeo F, Herker E, Maldener C, Wissing S, La¨chelt S, Herlan M, Fehr
M,Lauber K,
Sigrist SJ, Wesselborg S et al. (2002) A caspasesrelated protease regulates apoptosis in yeast. Mol Cell 9: 911–917