This study examines organismal death in C. elegans by observing two phenomena: 1) a wave of body wall muscle contraction (rigor mortis-like) called death contraction (DC) and 2) a wave of intestinal necrosis causing blue fluorescence (DF). The researchers find that DC occurs in an anterior-to-posterior wave through muscle contraction. DC waves correlate with and precede DF waves. Both are accompanied by calcium release and a drop in ATP levels. Long-lived daf-2 mutants show resistance to DC, suggesting organismal death pathways can be modulated to extend lifespan.

1. Review of
Coupling of Rigor Mortis and Intestinal Necrosis
during C. elegans Organismal Death
Evgeniy R. Galimov, Rosina E. Pryor, Sarah E. Poole, Alexandre
Benedetto, Zachary Pincus, David Gems
Cell Reports (March 2018)
DOI: 10.1016/j.celrep.2018.02.050
Presented By:
Junaed Ahmed
Reg: 2016423003

2. AGING
Development,
Reproduction
Senescence Pathology
Organismal
death
What About organismal death?
Apoptosis
,
Necrosis Cell death

3. KEY TERMS
Rigor Mortis (Latin: rigor “stiffness”, mortis “of
death”) -
is the process that causes the muscles in the body to
stiffen resulting in rigidity due to a range of chemical
changes in the muscle structure.
DC –
Death contraction is a rigor mortis like phenomenon in C.
elegans
DF –
Death fluorescence is a wave of blue autofluorescence
caused by calcium propagated wave of intestinal necrosis.
tBOOH –
tert-butylhydroperoxide (tBOOH, 14%) is an organic
peroxide works as killing agent of C. elegans

4. HIGHLIGHTS
• A wave of body wall muscle contraction occurs
during C. elegans organismal death
• This rigor mortis like phenomenon is coupled to a
wave of intestinal necrosis
• Both waves are accompanied by Ca2+ release and a
drop in ATP levels
• Properties of long-lived daf-2 mutants suggest
resistance to organismal death

6. EXPERIMENTAL PROCEDURES USED
• Microscopy
• Nomarski and epifluorescence microscopy were performed
• Death Contraction Assays
• tBOOH-induced death were observed using time-lapse photography
• Changes in worm body length were analyzed by converting multiple
images into kymographs.
• Construction of ATP Reporter Strain
• A transgenic C. elegans were created using microinjection and
identified by Queen-2m fluorescence
• Extra chromosomal transgene arrays were integrated using Gamma-
irradiation.
• ATP Measurements
• For estimates of relative ATP levels using the Queen-2m sensor, lex
of 402/15 nm or 482/28 nm and lem of 545/25 was measured and
402ex/482ex ratio calculated.

7. 1. DC Occurs in an AP Wave

8. 2. DC is Caused by Muscle Contraction

9. 3. DC Waves Correlate with but precede DF

10. 4. ATP levels drop during Organismal Death

11. 6. daf-2 mutants are resistant to
DC

12. Hypothetical
Model of
Organismal
Death in .
elegans and its
Relation to
Mammalian
Rigor Mortis.

13. THE END
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