Midterm #2 Flashcards
1
Q
What are the stages of plants being infected with Claviceps fungus?
A
-
After infection in plant:
- Fungal spores germinate in flower ovaries - destroy ovaries
- Grain kernal (seed) replaced by sclerotia
- Fungal fruiting body
- Brownish violet horn-shaped structure
-
At maturity:
- Sclerotia fall off host plant, over-winter in soil
-
Next growing season:
- __Sclerotia sporulate
- Spores can infect new crop
- Insects carry fungal spores from host plant to other susceptible plants
2
Q
What are the two possible contributing factors linking ergotism and the bubonic plague?
A
- Either type of ergotism can lower the immune system - makes person more susceptible to infection by plague
- If rats ate ergot infected rye, they would die and fleas would transfer to alternate human hosts
- Also have correlation between between weather and number of plague deaths
- Fewer plague victims during dry weather
- Fewer plague victims in areas where rye is not staple bread
3
Q
Which NT receptors does ergoline effect?
What is the main receptor type it effects? What is this NT involved in?
A
- Many alkaloid compounds identified from ergot and derived from ergoline - show antagonistic and agonist effects on serotonin, dopamine, and adrenergic receptors
- Serotonin is CNS and PNS NT involved in mood, sleep, appetite, temperature regulation, pain perception, vomiting, regulation of BP, depression, anxiety, migraines
- Numerous 5HT receptor types
- How alkaloid action affects these receptors is somewhat unclear
4
Q
What are some modern uses for ergot alkaloids?
A
- Treat migraines
- Decrease prolactin levels resulting from pituitary tumours
- Decrease postpartum hemorrhage
- Treat senility and Alzheimer’s dementia
5
Q
Ergotamine biosynthetic pathway
A
6
Q
What are some of the ways that drugs can affect synapses?
A
- Increase the number of impulses
- Release NTs from vesicles with or without impulses
- Block reuptake or block receptors
- Produce more or less NTs
- Prevent vesicles from releasing NTs
7
Q
What are eicosanoids?
A
- Signaling molecules created from breakdown of arachidonic acid
- E.g., prostaglandins (inflamamtion, pain, fever, increase BP); epoxides; HPETEs
8
Q
What is the physiological role of PGE2?
A
- Vasodilator
- Maintains ductus arteriosus
- Helps maintain placental blood flow
- Clinical significance
- Alprostadil
- Targets PGE2
9
Q
Role of PGI2?
What are its analogues?
A
- Inhibitor of platelet aggregator
- Mild bronchodilator
- Inhibits histamine release
- Evokes renin release
- Produced by vascular endothelium
- Hypotensive (more than PGE2)
-
Analogues:
- __Treprostinil
- Iloprost
- PVD
- Pulmonary hypertention (in combination with PGE2)
10
Q
Role of PGF2?
A
- Contracts uterus
- Bronchoconstriction
- Contracts longitudinal muscles
- Induces ocular inflammation
- Decrease IOT by increasing US outflow
- Increases hepatorenal syndrome
11
Q
Role of PGD2?
A
- Anti-platelet aggregatory
- Bronchoconstrictor
- Evokes renin release
- Mainly secreted by mast cells
- Constituent of slow release substance of anaphylaxis
- Slowly metabolised
12
Q
Role of TXA2?
A
- Produced by platelets
- Potent inducer of platelet aggregation
- Constituent of release reaction
- Renal vasoconstriction
- Bronchoconstriction
13
Q
What is the process of the SAR response?
A
- SAR = systemic acquired resistance
- Disease organisms stimulate plant to make SA
- Increase in SA causes plant to produce plant defense proteins
- These proteins provide resistance to a variety of pathogens
14
Q
What is the process of the induced systemic resistance response?
A
- Plant growth promoting rhizobacteria (PGPR) stimulate plant roots, cause production of plant defense hormones
- Hormones ethylene and jasmonate increase in plant and induce resistance to variety of pathogens
15
Q
What genes do plants need to be resistant to diseases?
A
- Need BOTH resistance gene in plant genotype and pathogen with ligand
- R_ = single dominant resistance gene in plant
- Avr_ = avirulence gene - ligand
