Exam 2 Review Questions

Question 1

1. Blister buttercup, Bur buttercup, and Baneberry contain ranunculin, a chemical precursor to what strong digestive irritant? How is that irritant derived from ranunculin?

Answer 1

• Runuculin is a precursor to protanemonin
• rununculin is exposed to plant enzymes producing protoanemonin

Question 2

1. What are the toxins found in plants of the nightshade family (ex. Jimsonweed, black henbane)? How do these toxins affect livestock (mechanism)? What are the symptoms of nightshade poisoning?

Answer 2

1. Steroidal glycoalkaloid
   
   1. Solamine
   2. Hyoscine à Scopolamine or Zombie Drug
   3. Hyoscyamine à Atropine
2. Mechanism of nightshade poisoning
   
   1. Blocks action of cholinesterase
   2. Accumulation of acetylecholine
   3. Inhibits parasympathetic nervous system
3. Symptoms of nightshade poisoning
   
   1. Initial CNS excitation
   2. Subsequent CNS depression
   3. Decreased heart rate
   4. Muscle weakness
   5. Dilated pupils
   6. Stomach rupture and paralysis of GI tract

Question 3

1. Diarrhea is a common symptom of toxicosis by which plant(s)?

Answer 3

1. Leafy spurge (euphorbia esulas)
2. Western Yarrow (achillea millefolium)

Question 4

1. Which species is most susceptible to poisoning by lectins? Where are lectins most concentrated within a plant?

Answer 4

1. Horses are most susceptible
2. Its concentrated in seeds

Question 5

1. What is the mechanism of action for lectin poisoning?

Answer 5

1. Endocytosis
2. Passes through organelles to the endoplasmic reticulum
3. Depurinates ribosomes at a rate of 1500 ribosomes per minute
4. Cell death

Question 6

1. Primary photosensitization is caused by ingestion of or direct contact with what plant compounds? Which plants contain these compounds?

Answer 6

1. Absorption of photodynamic pigments
2. Plants that cause primary photosensitization
   
   1. St. John’s Wort (hypericum perforatum)
   2. Buckwheat (fagopyrum esculentum)
   3. Spring Parsley (cymopterus watsonii)

Question 7

1. Why do livestock with severe liver damage sometimes develop secondary (hepatogenous) photosensitization?

Question 8

1. Which plants are generally associated with secondary photosensitization?

Answer 8

1. Horsebrush (tetradymia spp.)
2. Tansy mustard (duscurania pinnata)

Question 9

1. How to pyrrolizidine alkaloids damage the liver?

Answer 9

1. Pyrrolizidine alkaloids go to the liver
2. The liver transforms it via bioactivation to a toxic pyrrole
3. Toxic pyrrole inhibits mitosis, preventing the formation of new hepatocytes

Question 10

1. Which species is least affected by pyrrolizidine alkaloids? How can this help manage plants like Fiddleneck and Hound’s tongue?

Answer 10

1. Sheep are least effected by PA’s; they can eat 20 times more
2. Sheep can be used to graze Fiddleneck and Hound’s Tongue to protect cattle, horses, and sheep

Question 11

1. Puncture vine contains saponins, the ingestion of which can cause what liver disorder?

Answer 11

1. Biliary occlusive photosensitivityà inflammation causes the bile duct to be obstructed so bile can’t be excreted, causing a phylloerythrin build up

Question 12

1. What conditions favor blue green algal blooms in stock ponds? Define any specific terms.

Answer 12

1. Algae blooms with high temperatures
2. Specific terms?

Question 13

1. How would you recognize photosensitization (primary or secondary) in affected livestock?

Answer 13

1. Remove from plantà does it help?
2. Noà Liver biopsy
   
   1. Difference between secondary types
      
      1. Biliary occlusive if caught early can be treated and recovery is possible
      2. History of possible exposure to plant

Question 14

1. Generally, what is a teratogen? Give three examples.

Answer 14

1. A teratogen causes birth defects
2. Examples
   
   1. Milk vetches (astragalus)
   2. Locoweed (oxytropis)
   3. Lupine (lupinus spp)
   4. Poison hemlock (conium maculatum)
   5. Ponderosa pine (pinus ponderosa)

Question 15

1. What conditions must be met for a plant compound to be teratogenic?

Answer 15

1. Cross placenta easily
2. Right species
3. High enough concentration
4. Right gestational time

Question 16

Which plant teratogen is present in milk vetches? How does this compound affect cattle? Is timing important with this chemical?

Answer 16

1. Swainsonine (indolizidine alkaloid)
2. Swainsonine affects cattle??

Question 17

Which species cause(s) crooked calf disease? What are the symptoms?

Answer 17

1. Lupine (lupinus spp.) causes crooked calf disease
2. In sheep, it causes head pressing.

Question 18

1. How does cyclopia occur in sheep?

Answer 18

1. Western False Hellebore (veratrum californicum) disrupts the sonic hedgehog signaling pathway

Question 19

Typically, a cow that has aborted can recover and conceive again. However, if not monitored closely after the loss of calf, what condition can lead to permanent loss of fertility?

Answer 19

1. Retained placenta leading to secondary uterine infections

Question 20

1. How does cyclopamine cause birth defects mostly in sheep?

Answer 20

1. Western False Hellebore (veratrum californicum) disrupts the sonic hedgehog signaling pathway. The cyclopamine causes cyclopia and facial deformities if ingested on the 14^th day of gestation. By the 30-35^th day, theres shortened legs and completely or partially absent trachea.

Question 21

1. Describe the three syndromes associated with Lupine toxicosis.

Answer 21

1. Cleft palate
2. Acute fatal neurological disease
3. Lupinosis
4. Limb deformity
5. Crooked calf disease