Lecture 4 - funnel web spiders

Question 1

describe the spiders within Hexathelidae

Answer 1

> male hexathelidae spiders are the most medically important
toxin type that is lethal to vertebrates are the delta toxins:
- inhibit tetrodotoxin -sensitive voltage-gated sodium channels by binding to site three
- slows inactivation, causes prolongation of action potential duration resulting in repetitive firing in automatic and motor nerve fibres
antivenom for atrax/hadrochyche

Question 2

describe Theraphosidae

Answer 2

> all species capable of causing notable envenomations are from Africa, asia or australia. no american species cause these effects
> subfamily:
 -harpactirinae
 - poecilotheriinae
 - selenocosmiinae
> no antivenom

Question 3

describe mygalomorphae

Answer 3

> group of basal spiders that include tarantulas and funnelwebs
downward pointing chelicerae

Question 4

describe mesothelae

Answer 4

> sister group to all other spiders
retain many plesiomorphic characterisitcs
long-thought to lack venom but recent evidence indicates otherwise

Question 5

what are in the order araneae?

Answer 5

> mesothelae
mygalomorphae
aranemorphae

Question 6

what are latrodectus?

Answer 6

> massive neurotransmitter release
resulting in extremely painful muscle cramping including ‘ironing board’ stomach
Antivenom made in australia and usa
red backs

Question 7

describe araneomorphae

Answer 7

> most derived spiders
web builders
inward facing fangs

Question 8

describe neosparassus

Answer 8

> occupy unique ecologica niche
fight instead of flight behaviour
only huntsman spiders capable of causing clinically significant systemic envenomations
feed exclusively on insects but venom also contains a unique vertebrate specific toxin that is used for defense
no antivenom

Question 9

describe phoneutria

Answer 9

> priapism, loss of muscle control, severe pain, difficulty breathing and if its victim is not treated with anti-venom, death due to oxygen deprivation as a consequence of respiratory failure
priapism causing toxins, if controlled, reduced and separated from other (lethal) toxins has significant potential as a new viagra
antivenom in brazil

Question 10

describe loxosceles

Answer 10

> tissue destroying venom

> mexican antivenom

Question 11

Describe sicariidae

Answer 11

> pruduce sphingomyelinase

> destroy mylein sheaths

Question 12

what is the evolutionary purpose of venoms?

Answer 12

> defence
competitor deterrence
prey capture

Question 13

compare and contrast veno to poison

Answer 13

> poison
- a toxin that gains entry to the body via the gastrointestional tract, the respiratory tract of absorbtion through intact body layers (e.g., ciguatoxin). typically alkaloidal or other ring structures
Venom:
- a toxin or mixture of toxins that normally gain access to the body by injection through the intact skin (e.g, by a fish spine or snake fang). typically proteins or peptides

Question 14

Describe venom toxins

Answer 14

> complex mixtures
 - proteins
 - salts
 - organic molecules
> proteins
 - result of 'toxin recruitment events'
 - source from diverse tissues
 - toxin genes were amplified to obtain multigene families
 - extensive neofunctionalisation
>