Study Set Content:
)Myriapods
(centipedes and millipede
Insects
water bugs, assassin bugs, and wheel bugs
Beetles
blister beetles
Lepidoptera
butterflies, moths, and caterpillars
)Hymenoptera
(ants, bees, and wasps
Any arthropod may bite or sting and
not eject venom
Many scorpion venoms contain() proteins, peptides, amino acids, nucleotides, and salts, among other components.
low-molecular-weight
appear to affect potassium or chloride channels composed of 20 to 40 amino acid residues with 3 or 4 disulfide bonds.
Short-chain toxins
affect mainly the sodium channel, composed of 58 to 76 amino acid residues (6500–8500 Da) with four disulfide bonds.
Long-chain toxins
Symptoms and signs of scorpion envenomation differ considerably depending on the species: o Family ()e and their sting gives rise to localized pain, swelling, tenderness, and mild paresthesia.
Vejovidae
Envenomations by some members of the genus () are clinically the most important. In children, their sting may produce initial pain. The child becomes tense and restless and shows abnormal and random head and neck movements.
Centruroides
() stings display visual signs, including nystagmus roving eye and oculogyric movements.
Centruroides sculpturatus
All spiders except the () family possess a venom apparatus that produces neurotoxins designed to paralyze or kill prey.
Uloboridae
are voltage-dependent open-channel blockers (sodium, calcium,and potassium channels) and/or blockers on the ion channel associated with glutamatereceptors. They also act on nicotinic acetylcholine receptors.
Acylpolyamines
Contains three classes of agatoxins that target ion channels.
AGELENOPSIS SPECIES (AMERICAN FUNNEL WEB SPIDERS)
appear to be use-dependent, noncompetitive antagonists of the glutamate receptor channels.
α-agatoxins
cause increased spontaneous release of neurotransmitters from presynaptic terminals and repetitive action potentials in motor neurons. Specific for insect sodium channels.
µ-agatoxins
are a structurally diverse group of peptides that are selective or voltage-activated calcium channels.
ω-amatoxins
, a family of high-molecular-weight proteins that are found in Latrodectus venoms, target different classes of animals including vertebrates, insects, and crustaceans
latrotoxins
is the most studied protein that is toxic only to vertebrates and not to insects or crustaceans.
α-Latrotoxin
