Post on 29-Dec-2015
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 caspases-related protease regulates apoptosis in yeast. Mol Cell 9: 911–917