LATG 11: Gnotobics

Question 1

True or False: Gnotobiotes, by definition, are germ-free animals.

Answer 1

False

Question 2

True or False: 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 2

True

Question 3

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

Answer 3

specific pathogen free

Question 4

True or False: Axenic animals are gnotobiotes.

Answer 4

True

Question 5

True or False: The development of the Trexler flexible film isolators marked the beginning of modern gnotobiotic research.

Answer 5

True

Question 6

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

Answer 6

increased accessibility of animals

Question 7

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

Answer 7

laminar flow rack

Question 8

True or False: Isolators must operate with positive pressure with respect to the room.

Answer 8

False- negative pressure

Question 9

What function does a transfer sleeve serve?

Answer 9

To connect the supply cylinder to the isolator entry port

Question 10

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

Answer 10

True

Question 11

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

Answer 11

containment

Question 12

True or False: Supplies must be sterilized before being passed through the supply cylinder.

Answer 12

False- sterilized inside supply chamber

Question 13

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

Answer 13

sterilization

Question 14

True or False: The tissue enzyme level of axenics tends to be higher than those of normal animals.

Answer 14

False

Question 15

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

Answer 15

A solution containing a variety of normal flora bacteria

Question 16

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

Answer 16

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

Question 17

True or False: Axenic rats have smaller hearts, livers, and lungs compared to non-axenic rats.

Answer 17

True

Question 18

True or False: 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

Which amino acids are required in lesser quantities in axenic animals?

Answer 19

lysine and cysteine

Question 20

True or False: Gnotobiotic animals require fortified feed to replace the vitamins broken down by autoclaving.

Answer 20

True

Question 21

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

Answer 21

to optimize litter size

Question 22

True or False: Hysterectomy derivations are done using nonaxenic mothers and axenic foster mothers.

Answer 22

True

Question 23

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

Answer 23

True

Question 24

What represents a difference between hysterectomy derivation and embryo transfer?

Answer 24

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

Question 25

What term refers to the thousands of microbial species that inhabit a specific host?

Answer 25

Microbiome

Question 26

What is the advantage of giving gnotobiotes a cocktail containing normal intestinal flora?

Answer 26

It serves to normalize the gut physiology and anatomy.

Question 27

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

Answer 27

to optimize litter size

Question 28

For which purpose does the transfer sleeve of an isolator have nipples?

Answer 28

sterilant injection

Question 29

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

Answer 29

supply cylinder

Question 29

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

Answer 29

supply cylinder

Question 30

Animals that are free from all demonstrable microorganisms are called:

Answer 30

anexic

Question 31

The intestinal wall of axenic animals is _____________ than the intestinal wall of animals having a normal microflora.

Answer 31

thinner

Question 32

The most basic requirement for an isolator is that it must be:

Answer 32

impervious

Question 33

What does the term gnotobiotics mean?

Answer 33

well-known; refers to animals who's microflora is defined

Question 34

True or False: A germ-free animal is a type of gnotobiote.

Answer 34

True

Question 35

True or False: Axenic rats are not available commercially; they must be developed within the individual animal facility.

Answer 35

False

Question 36

What are sterilization methods used to support gnotobiotic systems?

Answer 36

steam autoclaving, dry heat, peracetic acid, ethylene oxide, gamma irradiation, membrane filtration, chlorine dioxide, hydrogen peroxide gas plasma

Question 37

What is an axenic animal?

Answer 37

an animal that is free of all demonstrable organisms

Question 38

What is the difference in an axenic animal's cecum from other animals?

Answer 38

it is greatly enlarged

Question 39

Are all gnotobiotes axenic? Why or why not?

Answer 39

No- also includes defined flora animals

Question 40

What is the process of embryo transfer for deriving an axenic animal?

Answer 40

embryos from superovulated dam are removed, washed, and transferred to reproductive tract of axenic female in an aseptic isolator

Question 41

Why should you use a foster mother whose coat color is different from the donor mother in a hysterectomy derivation to produce axenic animals?

Answer 41

to make sure foster pups are identifiable from the natural litter

Question 42

What is a Schaedler cocktail and why is it given to axenic animals?

Answer 42

a cocktail of normal, nonpathogenic intestinal bacteria given to normalize gut

Question 43

What is a transfer sleeve?

Answer 43

a flexible, plastic tube that is the same diameter as entry port and supply cylinder that serves as an entrance/exit

Question 44

How do litter sizes compare between axenic animals and defined flora animals?

Answer 44

axenic animals have smaller litters

Question 45

Axenic animals require more vitamins ____ and _____, and have lower requirements for vitamins ___ and ____.

Answer 45

K and B; A and E