Chapter 11 Gnotobiotics Flashcards
Gnotobiotics
“well-known life”, is the study of animals whose microflora is completely defined.
Germ-free, also known as axenic
free of all demonstrable microorganisms.
defined flora (DF)
DF animals are animals that were originally germ-free but were given a known group of bacteria and/or other organisms to aid their digestive functions.
specific pathogen-free animals (SPF).
SPF animals have normal flora but are free of particular organisms, usually pathogenic, but they are not gnotobiotes.
isolator system
is a device that creates a barrier between animals and the outside environment, either by preventing microorganisms outside the system from entering the isolator (exclusion), or by confining potentially harmful microorganisms within the system (containment).
Rigid isolators
are constructed of stainless steel or Plexiglas®.
Flexible isolators
are usually made of clear polyvinyl or polyurethane plastic film
Semi-rigid isolators
may be made of impact-resistant material (such as polypropylene) on all but one side and have a flexible film (such as polyurethane) on the front side.
Flexible film isolators are considerably less expensive than stainless steel isolators
How long must isolators undergo testing?
3-6 weeks
Laminar flow cabinets or laminar flow racks
provide a cage or rack environment with a large volume of air that is filtered, sterile, and in a laminar flow.
Nutrient requirements also differ for axenic animals
hey tend to have higher requirements for total food and water intake, vitamin K, B vitamins, and choline than nonaxenic animals.
They have lower requirements for vitamin A and vitamin E, and for the amino acids lysine and cysteine.
What diseases can pass through the placenta barrier?
Mycoplasma spp. and Pasteurella spp.
Kilham rat virus and lymphocytic choriomeningitis virus
Schaedler cocktails
a “cocktail” of normal symbiotic (nonpathogenic) intestinal bacteria to normalize the gut physiology and anatomy.
defined flora animals
Animals that have received a cocktail of known microorganisms
resume text book flashcards from defined flora animals
resume text book flashcards from defined flora animals
name the two types of gnotobiotic animals?
axenic (germ free) and defined flora
…..is a cocktail of normal symbiotic intestinal bacterial given to axenic animals to normalize gut physiology.
Schaedler cocktail
a device that creates a barrier to between the germ-free animal and the outside environment is called an …..
isolator
a stainless steel container in which materials and supplies are sterilized before being introduced into an isolator is called a ……
supply cylinder
which digestive organ is larger in axenic animals than in animals with normal flora?
cecum
What does the term “gnotobiotics” mean?
a. Precarious life
b. Well-known life
c. Unnatural biology
d. Abnormal biology
b. Well-known life
Animals that were originally germ-free but were given a known group of bacteria are called ______________ animals.
a. axenic
b. specific pathogen free
c. defined flora
d. normal
c. defined flora
Animals that have a normal intestinal flora but are free of particular disease-causing organisms are called:
a. axenic
b. specific pathogen-free
c. defined flora
d. normal
b. specific pathogen-free
What is the term for using isolator caging to prevent microorganisms from reaching the animals housed inside?
a. Prevention
b. Containment
c. Inclusion
d. Exclusion
d. Exclusion
What is another name for an axenic animal?
a. Germ-free animal
b. Clean-gut animal
c. Normal flora animal
d. Aflora animal
a. Germ-free animal
What is a difference between embryo transfer and hysterectomy derivation?
a. In embryo transfer, the embryos are at an early stage of development; in hysterectomy derivation, the fetuses are
at term.
b. In embryo transfer, the embryos are transferred to a surrogate mother; in hysterectomy derivation, the fetuses
are returned to their biological mother.
c. In embryo transfer, the pups are removed at birth and adopted by a foster mother; in hysterectomy derivation,
the pups are bottle-fed as orphans.
d. None of the above
a. In embryo transfer, the embryos are at an early stage of development; in hysterectomy derivation, the fetuses are
at term.
Why have laminar flow cabinets recently become more frequently used than isolators for maintaining gnotobiotic
animals?
a. Decreased cost
b. Increased accessibility of animals
c. Less stringent sterile technique requirements
d. Reduced training requirements
b. Increased accessibility of animals
Why should the existing pups be removed from the axenic foster mother before introducing the new pups?
a. To ensure genetic integrity of the mice
b. To prevent maternal neglect
c. To ensure adequate suckling space
d. To prevent trampling of the pups
a. To ensure genetic integrity of the mice
. Axenic animals have an intestinal wall that is _____________ than in animals with a normal microflora.
a. thicker
b. thinner
c. less fibrous
d. more porous
b. thinner
Which characteristic is true of axenic animals as compared to animals with normal microflora?
a. Axenic animals have lower levels of tissue enzymes.
b. Axenic animals have thicker intestinal walls.
c. Axenic animals have a larger thymus.
d. Axenic animals have a shorter life span.
a. Axenic animals have lower levels of tissue enzymes.
Which characteristic is true of axenic animals as compared to animals with normal microflora?
a. Axenic animals have shorter life spans.
b. Axenic animals need less food and water.
c. Axenic animals must be given routine doses of antibiotics.
d. Axenic animals have an immune system that is not well developed.
. d. Axenic animals have an immune system that is not well developed.
What are “Schaedler cocktails” or “altered Schaedler cocktails?”
a. Mixtures of antibiotics to keep germ-free animals from becoming infected
b. Mixtures of extra nutrients to meet the needs of gnotobiotes
c. Solutions containing a variety of normal intestinal flora
d. Salt solutions to maintain body electrolytes
c. Solutions containing a variety of normal intestinal flora
When deriving axenic animals, which microorganisms must be monitored to ensure that they have not passed transplacentally to the pups? a. Salmonella spp. b. Mycoplasma spp. c. Escherichia coli d. Giardia spp.
. b. Mycoplasma spp.
Axenic animals have lower requirements for which of the following nutrients?
a. Vitamin A
b. Vitamin K
c. Vitamin B
d. Vitamin C
a. Vitamin A
Which anatomical feature is enlarged in axenic animals?
a. Cecum
b. Liver
c. Thymus
d. Lymph nodes
a. Cecum
Which of the following is a characteristic of axenic animals?
a. Their blood cholesterol level is higher than in normal animals.
b. They have larger thymuses than normal animals.
c. They have difficulty absorbing the fats they ingest.
d. Their immune system is more developed than in normal animals.
a. Their blood cholesterol level is higher than in normal animals.
Axenic animals generally have which of the following characteristics?
a. Thick walled intestines
b. Poor muscle development
c. High tissue enzyme levels
d. Strong immune systems
b. Poor muscle development
- Which of the following types of animals are completely free of all detectable microorganisms?
a. Axenic
b. Specific pathogen free
c. Cesarean-derived
d. Barrier-reared
a. Axenic
Gnotobiotics is the study of animals whose _____ is completely known.
a. genome
b. ancestry
c. phenotype
d. microflora
d. microflora
Which of the following cabinets provides a cage environment with linear-flowing filtered sterile air?
a. Laminar flow cabinet
b. Class III biosafety cabinet
c. Fume hood
d. Cage changing station
a. Laminar flow cabinet
What term describes the complete killing of all living organisms?
a. Disinfection
b. Sterilization
c. Asepsis
d. Decontamination
b. Sterilization
A ___________ is a flexible plastic tube used to move items into or out of the isolator.
a. transfer sleeve
b. supply cylinder
c. laminar flow tube
d. Trexler tube
a. transfer sleeve
What is the cause of a low litter size in axenic gerbils?
a. Lower level of hormones
b. Reduced milk capacity of the female
c. Enlarged cecum in the axenic animals
d. Lower sperm production in the male
c. Enlarged cecum in the axenic animals
