15. C. elegans IIII Flashcards
(19 cards)
What are the stages of the normal C. elegans life cycle?
Embryonic development, Hatching (L1), Larval stages (L1→L2→L3→L4), Adulthood, Molting
The complete cycle takes approximately 3 days at 20°C.
What occurs during embryonic development in C. elegans?
Cell division, metamorphosis, and elongation
This development occurs within the egg.
What happens during the hatching stage of C. elegans?
Emerges as an L1 (first larval stage)
This is the initial larval stage post-embryonic development.
How many larval stages does C. elegans progress through?
Four stages: L1, L2, L3, L4
Each stage is separated by molting.
What is the adult stage in C. elegans characterized by?
Reproductive maturity, able to produce eggs
This occurs after the larval stages.
What is molting in the context of C. elegans development?
The process of shedding the outer cuticle between each stage
Essential for growth as C. elegans progresses through its life cycle.
What is L1 Arrest in C. elegans?
Occurs when worms hatch in absence of food; development pauses at L1 stage
Can survive 2-3 weeks without food.
What happens during the Adult Reproductive Diapause in C. elegans?
L4 larvae become adults but stop producing embryos; germline shrinks
Retains reproductive capacity but with reduced fitness if food returns.
What triggers the Dauer Stage in C. elegans?
Food scarcity, high population density, high temperature
This stage is an alternative to the L3 stage.
How long can C. elegans survive in the Dauer Stage?
Up to 3+ months
This stage allows for extreme resistance to harsh environmental conditions.
What are the morphological adaptations of C. elegans in the Dauer Stage?
Radial constriction, thickened cuticle, sealed buccal cavity, sealed anus, arrested germline development, shrunken pharynx, intestine, and hypodermis
Adaptations are specialized for long-term survival and dispersal.
What are the metabolic adaptations of C. elegans in the Dauer Stage?
Slowed metabolism, no shift to aerobic respiration, increased lipid storage, conversion of lipids to glycogen, reliance on stored energy
These adaptations support energy distribution for locomotion.
What is the key pathway involved in dauer formation in C. elegans?
Insulin-like signaling pathway
This pathway integrates environmental signals to determine developmental outcomes.
What role do ciliated neurons play in C. elegans?
Detect food, pheromones, and temperature
They serve as environmental sensors for signaling pathways.
What is the function of DAF-2 in C. elegans?
Insulin/IGF receptor expressed throughout the worm
It plays a critical role in the insulin-like signaling pathway.
What happens when food is abundant in C. elegans?
Insulin activates DAF-2 → Kinase cascade → DAF-16 is phosphorylated and excluded from nucleus
This leads to reproductive development proceeding.
What occurs when food is scarce in C. elegans?
Low insulin → Low DAF-2 activation → DAF-16 enters nucleus → Activates dauer programs
This suppresses reproductive programs.
True or False: C. elegans can adapt its development in response to environmental stressors.
True
It employs mechanisms like L1 Arrest, Adult Reproductive Diapause, and Dauer Stage.
Fill in the blank: The complete C. elegans life cycle takes approximately _______ at 20°C.
3 days
The cycle duration is temperature-dependent.
