Signaling Flashcards
Ecdysteroid
The collective term for derivatives of ecdysone. Ecdysteroids trigger mainly molting (apolysis) and vitellogenin production by affecting gene expression.
Hormone
A chemical produced by specialized tissues and released into the blood that affects target tissues elsewhere in the body.
Neurohormone
A hormone produced by neurosecretory cells and released ffrom a neurohemal organ into the hemolymph
Neuronal signaling
Transmission of information in a multicellular organism via nerves by means of electrical and chemical signals
Neurotransmitter
A chemical released at the neural synapse that enables the nervous activation to pass to an adjacent neuron.
Paracrine signaling
A type of cell signaling where the target cell is near the signaling cell
Prothroracic gland
the endocrine gland that synthesizes and secretes ecdysteroids
Ring gland
The composite endocrine gland of larval dipterans consisting of the prothoracic gland, corpus allatum, and corpus cardiacum.
Growth Factor Proteins
determine tissue types at all life stages
Morphogen proteins
A substance that influences the movement and gene transcription of cells through a concentration gradient.
Steroids/sesquiterpenoids
(e.g. juvenile hormone) are small organic molecules that regulate development, reproduction, and many other processes
Types of chemical messengers
- Growth Factor proteins
- Morphogen proteins
- Steroids/sesquiterpenoids
- Neurotransmitters
- Peptide/neuropeptide
- Immunity factors
Neurotransmitters
small organic molecules that enable electrochemical communication with the nervous system and regulate muscle activity
Peptide/neuropeptide hormones
enable feedback between tissues and modulate all processes listed
Immunity factors
A type of chemical messenger that range from small molecules to large proteins
Autocrine signaling
type of cell signaling in which the cell that produces the signal bears receptor for it and is influenced by its action
cell communication with self
Paracrine signaling
A type of cell signaling where the target cell is near the signaling cell
cell communicating with nearby cells
Endocrine signaling
type of signaling where the target cell is must signal through the bloodstream
Secretion
cell synthesis, storage and release into extracellular space/hemolymph
degradation
circulating or cell surface enzymes
transduction
receptors on cell membrane or inside activate signaling pathway
Steroid hormones
regulate development, reproduction, immunity, water balance, metabolism, and behavior
precursor to steriods
squalene to cholesterol made by sesquiterpenoids
Prothoracic glands produce?
ecdysteroid hormones in nymph/larval stages
Example of an Endocrine gland
Prothoracic gland
what assists ecdysteroids into the cell?
nuclear hormone receptors (ex. ultraspiracle transcription factor)
Sources of Juvenile Hormone
- embryonic serosa
- corpus allatum
- male accessory gland
Juvenile hormone functions
in embryo- cuticle and midgut in larvae - prevents metamorphosis -affects pigmentation -stimulates feeding -supresses wandering -induces diapause - caste differentiation in termites
peptides that stimulate juvenile hormone
- allatotropins
- insulin- like peptides
- ecdysis triggering hormone
Juvenile hormone esterase
degrading enzyme that occurs in the hemolymph
juvenile hormone binding proteins
- prevent JH from binding to other hydrophobic sites on cell
- reduce enzyme metabolism by esterases
- provide a reservoir of JH
- aid in the transfer of JH
2 types of JH binding proteins
- juvenile hormone binding proteins
2. Lipophorins
Long term action
Neuroendocrine
from brain/NS to localized cells
Halloween Genes
set of genes coding for cytochrome P450 enzymes in ecdysteroid pathway; mostly in prothoracic gland
Ecdysteroid receptors
specific type of nuclear hormone receptors (NHRs); function as transcription factors
Ecdysone/20-OH ecdysone
most common ecdysteroid (20-hydroxyecdysone) is hydroxylated/activated form found in target tissues) secreted by prothoracic gland; primarily important for molting
Golden oil
JH originally obtained from abdomen/fat body (now from accessory glands) of male moth for bioassays with JH
Juvabione
“paper factor” JH specific to milkweed bug, affects development
Corpa cardaica
pair of organs closely associated with aorta, contains axons passing through to corpora allata
Neurosecretory cells
in ganglia of CNS, discharge products into hemolymph (make hormones)
Inka cells/Epitracheal glands
large neurosecretory cells attached to trachea near each spiracle; source of ecdysis-triggering hormone (ETH) and pre-ecdysis triggering hormone (PETH)
Synaptoids
swellings at the ends of axon branches of neurosecretory cells where secretions are released into hemolymph
Ecdysis triggering hormone (ETH)
peptide hormone produced by Inka cells; acts on VNchord to initiate ecdysis behavior/release of EH
Prothorarcictrophic hormone (PTTH)
made in neurohemal organ, signals to prothoracic gland for ecdysteroid synthesis
Polytene chromosome puffs
areas of gene activity - unraveled chromosome areas
Nuclear hormone receptors
receptors that function as transcription factors with ligand binding domain (binds ecdysone) or DNA binding domain (starts transcription); activates or inhibits gene expression
Allatotrophins
neurohormones that stimulate JH production in corpora allata (includes manse-AT)
Allatostatins
neurohormones that inhibit JH production in copora allata (reversible, includes manse-AST)
Allatoinhibin
neurohormone that inhibits corpora allata irreversibly
Insect growth regulator (IGR)
mimic action of hormone to disrupt molting and modify insect/mite growth
TcMet
protein coded by methoprene-tolerant (Met) gene; receptor of JH, controls start of metamorphosis
Acetylcholine
ACH, predominant excitatory neurotransmitter, binds to ion channels and G proteins coupled receptor
Choline acetyltransferase
synthesis from choline and acetyl coenzyme A
Acetylchonlinesterase
The enzyme present in the synapse that degrades acetylcholine to acetate and choline. Makes acetylecholine receptor available for the next release of neurotransmitter
Ligand gated ion channel
Voltage gated ion channels
Target of DDT and pyrethroid
Amino acid messengers
- Y-aminobutyic acid = GABA
- Glutamate
- Hisamine
- Biogenic amines
What are GABA receptors
A class of receptors thay respond to the neurotransmitter GABA in the CNS EX: Homopentameric chloride channel And metabotrophic receptors
G-Protein coupled receptors type
a type of metabotropic receptors
What is a Biogenic amines
slow acting neurotransmitters
Types of biogenic amines
- Dopamine
- Phenolamines
- Octopamine
- Tyramine
- Serotonin
- Melatonin
Nitric Oxide
another type of chemical messenger. Syntheized from L-arginine by NO synthase. short lived gas messenger that diffuses through membranes, produced cGMP
Eicosanoids
oxygenated metabolites of specific polyunsaturated fatty acid. produced in a variety of tissues
monoamine neurotransmitter transporter
signal transduction
primary purpose is to transfer signals from outside the cell to inside.
basic components of receptor signaling
- Ligand
- Receptor
- Effector or signaling system
Receptor tyrosine kinases
what are the 4 classes of GPCRs
- Rhodopsin-like receptor family
- Secretin-like receptor family
- Metabotrophic glutamate receptor-like family
- atypical 7 transmembrane proteins
Glial Cell
An accessory cell that surrounds neurons and provides them with nourishment and insulation
Synapse
The gap between two neurons, where electrical energy from nervous transmission is converted into chemical energy to stimulate the post-synaptic neuron
Neurons
Cellular building blocks that make up the nervous system
