Ch7 Nematodes

• Caenorhabditis elegans is a free-living nematode found worldwide and is closely related to arthropods, sharing a common ancestor.
• Caenorhabditis elegans is a bilaterian, so shares common similar development to mammals.
• 60-80% of human genes have orthologs in the Caenorhabditis elegans genome.
• Caenorhabditis elegans is a small (1mm), transparent worm that is easy to grow in the lab and is hermaphrodite, with males appearing <0.2% of times.
• The life cycle of Caenorhabditis elegans is fast, taking 3-4 days from egg to adult.
• Monoamines in C elegans include metabotropic monoamine receptors (35 human, 16 worm), ionotropic monoamine receptors (5 human, 9 worm), and receptors for monoamine neurotransmitters.
• Nematode dauer hormones may also act through a different receptor.
• Insulin peptides are a retrograde signal in nematode neurohormones.
• Salt sensing and klinokinesis behaviour are more likely to occur when dC/dt is negative.
• Nematode neurohormones AIA, AIB, AIZ, AIY, ASE, AWC, AFD, AWB are involved in salt sensing.
• Caenorhabditis elegans has a fully traced cellular lineage and fully mapped neuronal wiring, making it easy to genetically manipulate and study.
• Caenorhabditis elegans has many insulin-like peptides, with 40 INS peptides in the C. elegans genome.
• Dauer is a topic of study in C. elegans research.
• Insulin/insulin-like growth factor signaling is a process studied in C. elegans.
• Neuropeptides are a topic of study in C. elegans research.
• The neuronal genome is a topic of study in C. elegans research.
• Nuclear receptor signal transduction is a topic of study in C. elegans research.
• TGF-β signaling is a process studied in C. elegans.
• Ascaroside signaling is a process studied in C. elegans.
• Borghgraef C et al (2018) “Neuroendocrine regulation in the genetic model C elegans” is a book chapter.
• C. elegans is a genetic model used in research.
• Neurotransmitter signaling through heterotrimeric G proteins is a process studied in C. elegans.
• Nematodes have many insulin-like peptides, with 40 INS peptides in the C. elegans genome.
• Nematodes have dauer hormones, with 8 in the fly and 10 in humans, and these hormones act through RTKs and GPCRs.
• Nematodes have neurohormones that play a role in behavioral states, metabolism, and aging.
• Nematodes have neurohormones that affect learning, with insulin-like peptides also affecting learning.
• Nematodes have neurohormones that control navigation behavior, with insulin-like peptides also affecting learning.
• In worms that have lost their sense of touch, olfaction is enhanced.
• The FLP-20 receptor acts in a specialized interneuron.
• FLP-20 receptors act in AIY interneurons.
• Nematode neurohormones include AVK, NTC-1 (gustatory plasticity), NLP-49 (locomotion), FLP-1 (egg-laying, locomotion).
• ASI, DAF-7 (dauer) are expressed in the nervous system.
• FLP-20 conveys sensory information on different time scales, to diverse targets.
• Touch receptor neurons, premotor interneurons, motor neurons, and ASH chemo-nociceptors express FLP-20 receptors.
• RMG, FLP-21 (aggregation) are expressed in the nervous system.
• FLP-20 blocks synaptic input in AIY interneurons.
• FLP-20 also mediates cross-modal plasticity.
• RID, FLP-14 (locomotion), FLP-2 (locomotion) are expressed in the nervous system.
• This cross-modal plasticity involves FLP-20; flp-20 mutations mimic loss of touch.
• FLP-20 activates central node RID; promoting the release of efferent peptides that enhance peripheral motor and sensory circuits.