Chapter 11: Gnotobiotics Flashcards
What does the term “gnotobiotics” mean?
Well-known life
True or False
A germ-free animal is a type of gnotobiote
True
True or False
Axenic rats are not available commercially; they must be developed within the individual animal facility
False
Identify at least four sterilization methods used to support gnotobiotic systems.
1- Steam autoclaving
2- Dry heat (air)
3- Peracetic acid (2% w/v concentration)
4- Ethylene oxide
5- Gamma radiation
6- Membrane filtration
7- Chlorine dioxide
8- Hydrogen peroxide gas plasma
Define “axenic animal”
An animal free of all demonstrable microorganisms
What is different about an axenic animal’s cecum from other animals?
The axenic animal has a greatly enlarged cecum
Are all gnotobiotes axenic? Why or why not?
No. Axenic or germ-free animals are only one type of gnotobiote. Defined flora animals are also gnotobiotes.
Describe the process of embryo transfer for deriving an axenic animal.
The embryos from a superovulated mother are removed, washed, and transferred to the reproductive tract of a pseudopregnant axenic female in a surgical isolator
Why should you use a foster mother whose coat color is different from the donor mother in a hysterectomy derivation to produce axenic animals?
To make sure that the fostered pups are distinguishable from the foster mother’s own litter
What is a Schaedler cocktail and why is it given to axenic animals?
The cocktail of normal symbiotic (nonpathogenic) intestinal bacteria is given to normalize the gut physiology and anatomy
What is a transfer sleeve?
A flexible plastic tube of the same diameter as the empty port and the supply chamber
Which of the following are true of axenic animals as compared to animals with normal micro flora? Choose all that apply to axenic animals.
A- They have lower white blood cell counts
B- Their cecal content is more acidic
C- Their cholesterol level is generally higher
D- Their thymus is smaller
E- Their cecum is smaller
F- Their intestinal walls are thicker
A- They have lower white blood cell counts
C- Their cholesterol level is generally higher
D- Their thymus is smaller
How do litter sizes compare between axenic and defined flora animals?
Axenic animals generally have smaller litters
Axenic animals require more vitamins _______ and __________, and have lower requirements for vitamins ______ and _________.
A- A and K, B and E
B- K and B, A and E
C- A and E, K and B
D- E and K, A and B
B- Kane B, A and E
