Module 1A

A vocabulary-focused set of flashcards covering key terms and concepts from the lecture notes on C. elegans and model organisms.

Caenorhabditis elegans

A transparent nematode model organism used in genetics, development, and neurobiology; has a rapid life cycle and a stereotyped nervous system.

302 Neurons

The exact number of neurons in the adult C. elegans nervous system, arranged in cords and ganglia.

Hermaphrodite

The typical sex of adult C. elegans that can self-fertilize; occasional males exist.

HSN (Hermaphrodite-Specific Neurons)

Two serotonergic interneurons that control vulval muscle contractions and egg laying.

Serotonin (5-HT)

A neurotransmitter that regulates egg laying in C. elegans and other behaviors; levels depend on synthesis, transport, receptor sensitivity, neuronal firing, and reuptake.

SERT (Serotonin Transporter)

Protein that reuptakes serotonin from the synaptic cleft; inhibited by SSRIs like fluoxetine.

Fluoxetine (Prozac)

An SSRI that inhibits SERT, increasing serotonergic signaling.

Huntington’s disease

A dominant neurodegenerative disorder caused by polyglutamine expansions in Huntingtin (HTT).

HTT (Huntingtin)

The protein mutated in Huntington’s disease; expanded polyQ repeats lead to aggregation and neuronal toxicity.

Polyglutamine repeats (polyQ)

Expanded glutamine tracts in HTT that promote misfolding and aggregation.

Parkinson’s disease

Age-related movement disorder due to dopaminergic neuron loss; involves α-synuclein aggregates and Lewy bodies.

α-synuclein

Protein that aggregates in Parkinson’s disease and is used in worm models to study PD pathology.

Lewy bodies

Intracellular inclusions containing α-synuclein found in neurons of Parkinson’s patients.

LRRK2

Gene associated with familial Parkinson’s disease; mutations increase disease risk.

Squalamine

Sterol-amine from spiny dogfish shown to extend lifespan and rescue motility in PD worm models by inhibiting α-synuclein aggregation.

Alzheimer’s disease

Most common age-related neurodegenerative disorder with memory loss and cognitive decline, featuring amyloid plaques and tau tangles.

Amyloid-β (Aβ)

Peptide forming extracellular plaques derived from APP; hallmark of Alzheimer's pathology.

Tau protein

Microtubule-associated protein that becomes hyperphosphorylated and forms neurofibrillary tangles in Alzheimer's disease.

APP (Amyloid Precursor Protein)

Membrane protein cleaved to form Aβ; central to Alzheimer’s disease pathology.

Presenilin (PSEN)

Component of γ-secretase that cleaves APP; mutations affect Aβ production.

GFP (Green Fluorescent Protein)

Fluorescent reporter used to visualize gene expression and protein localization in living organisms.

mCherry (RFP)

Red fluorescent protein used in combination with GFP for dual-color imaging.

RNA interference (RNAi)

Gene silencing mechanism where double-stranded RNA reduces target gene expression; in C. elegans, often delivered by feeding bacteria.

CRISPR/Cas9

Genome editing system enabling targeted gene knockouts or insertions.

Apoptosis in C. elegans

Programmed cell death during development involving egl-1, ced-4, ced-3 (death) and ced-9 (protection); about 131 cells die during development.

Planaria (Planarian regeneration)

Flatworms capable of complete body regeneration; neoblasts drive regeneration, with full brain regeneration possible in days.

Neoblasts

Pluripotent stem cells in planaria responsible for regeneration.

Hirudotherapy

Medical use of leech saliva (hirudin) as an anticoagulant to improve blood flow and healing.

Limulus polyphemus

Horseshoe crab species used as a source of Limulus amebocyte lysate (LAL) for endotoxin testing.

Limulus Amebocyte Lysate (LAL)

Endotoxin detection test derived from horseshoe crab blood; coagulates in the presence of endotoxin.

Recombinant Factor C (rFC)

Synthetic alternative to LAL for endotoxin testing; produced through recombinant technology.

Monocyte Activation Test (MAT)

Endotoxin detection method using human monocytes to detect a broad range of pyrogens; potential alternative to LAL.

DAF-2/FOXO pathway

Insulin/IGF-1 signaling pathway in C. elegans; DAF-2 inhibits DAF-16/FOXO; reduced signaling promotes longevity.

DAF-16

FOXO transcription factor activated when IIS is reduced; promotes stress resistance and longevity.

Proteostasis

Maintenance of protein homeostasis; efficient turnover of misfolded proteins supports longevity.

3Rs (Replacement, Reduction, Refinement)

Ethical framework to minimize animal use and suffering in research.

Krogh’s principle

Guiding concept for choosing model organisms when studying conserved biological processes.