Chapter 11 Gnotobiotics

Question 1

Animals that have a normal intestinal flora but are free of particular organisms are called:

Answer 1

Specific pathogen-free

Question 2

Gnotobiotes, by definition, are germ-free animals.

Answer 2

False

Question 3

The first functional germ-free animal models were developed by scientists and technicians of the laboratories of bacteriology at the University of Notre Dame.

Answer 3

True

Question 4

Axenic animals are gnotobiotes.

Answer 4

True

Question 5

The development of the Trexier flexible film isolators marked the beginning of modern gnotobiotic research.

Answer 5

True

Question 6

What is the process by which isolators confine potentially harmful microorganisms within the system?

Answer 6

Containment

Question 7

A rack environment with a large volume of flowing, filtered, sterile air is called a:

Answer 7

laminar flow rack

Question 8

What function does a transfer sleeve serve?

Answer 8

To connect the supply cylinder to the isolator entry port.

Question 9

Isolators must operate with positive pressure with respect to the room.

Answer 9

False: either positive or negative.

Question 10

Why have laminar flow cabinets recently become more frequently used that isolators for maintaining gnotobiotic animals?

Answer 10

Increased accessibility of animals.

Question 11

Supplies must be sterilized before being passed through the supply cylinder.

Answer 11

False: they are sterilized inside the supply cylinder

Question 12

Before housing gnotobiotic animals, isolators should be tested multiple times for 3-6 weeks to ensure the abscence of contamination of bedding, shelves, feed and water.

Answer 12

True

Question 13

What is the term for the killing of all living organisms?

Answer 13

Sterilization

Question 14

Hysterectomy derivations are done using nonaxenic mothers and axenic foster mothers.

Answer 14

True

Question 15

What amino acids are required in lesser quantities in axenc animals?

Answer 15

Lysine and cyseteine

Question 16

Why are foundation colonies generally maintained in the defined flora state instead of in the axenic state?

Answer 16

To optimize litter size

Question 17

Gnotobiotic animals require fortified feed to replace the vitamins broken down by autoclaving.

Answer 17

True

Question 18

The process by which the embryos from a superovulated mother are removed, washed, and transferred to the reproductive tract of a pseudopregnant axenic female in a surgical isolator is called hysterectomy derivation.

Answer 18

False

Question 19

The tissue enzyme level of axenics tends to be higher than those of normal animals.

Answer 19

False

Question 20

Axenic rats have smaller hearts, livers, and lungs compared to non-axenic rats.

Answer 20

True

Question 21

What is a good choice to help maintain genetic integrity when producing axenic pups by hysterectomy derivation?

Answer 21

Make sure that the donor female and the foster mother have a different coat color.

Question 22

Pups that have been hysterectomy derived can be assumed to be germ-free and transferred to a barrier facility.

Answer 22

False

Question 23

What is a “Schaedler cocktail” or “altered Schaedler cocktail”?

Answer 23

A solution containing a variety of normal flora bacteria.

Question 24

Which vitamins are required in lesser quantities in axenic animals?

Answer 24

Vitamin A and Vitamin E

Question 25

Which vitamins are required in lesser quantities in axenic animals?

Answer 25

Vitamins A and vitamin E

Question 26

What is NOT an appropriate sterilization method for gnotobiotic systems?

Answer 26

Carbon dioxide

Question 27

What is the term for the stainless steel container in which materials and supplies are sterilized before placing in the isolator?

Answer 27

Supply cylinder

Question 28

Which of the following represents a difference between hysterectomy derivation and embryo transfer?

Answer 28

In hysterectomy derivation, the fetuses are at term, but in the other technique, embryos used are at an earlier stage of development.