细胞凋亡综述.ppt

APOPTOSIS: An overview
Sanjeev Sharma*, Aarti Bhardwaj$, Shalini Jain# and Hariom Yadav#
*Animal ics and Breeding Division, #Animal Biochemistry Division, National Dairy Research Institute, Karnal-132001, Haryana, India
$College of Applied Education and Health Sciences, Meerut, .
INTRODUCTION
Cell death by injury
-Mechanical damage
-Exposure to toxic chemicals
Cell death by suicide
-Internal signals
-External signals
Conted…..
Apoptosis or programmed cell death, is carefully coordinated collapse of cell, protein degradation , DNA fragmentation followed by rapid engulfment of corpses by neighbouring cells. (Tommi, 2002)

Essential part of life for every anism from worms to humans. (Faddy et al.,1992)
Apoptosis plays a major role from embryonic development to senescence.
Why should a mit suicide?
Apoptosis is needed for proper development
Examples:
The resorption of the tadpole tail
The formation of the fingers and toes of the fetus
The sloughing off of the inner lining of the uterus
The formation of the proper connections between neurons in the brain
Apoptosis is needed to destroy cells
Examples:
Cells infected with viruses
Cells of the immune system
Cells with DNA damage
Cancer cells
What makes a cell decide mit suicide?
Withdrawal of positive signals
examples :
growth factors for neurons
Interleukin-2 (IL-2)
Receipt of negative signals
examples :
increased levels of oxidants within the cell
damage to DNA by oxidants
death activators :
Tumor necrosis factor alpha (TNF-)
Lymphotoxin (TNF-β)
Fas ligand (FasL)
History of cell death / apoptosis research
1800s Numerous observation of cell death
1908 Mechnikov wins Nobel prize (phagocytosis)
1930-40 Studies of metamorphosis
1948-49 Cell death in chick limb & exploration of NGF
1955 Beginning of studies of lysomes
1964-66 Necrosis & PCD described
1971 Term apoptosis coined
1977 Cell death genes in C. elegans
1980-82 DNA ladder observed & ced-3 identified
1989-91 Apoptosis ge