Lab Animals - Mice Flashcards
1
Q
UCD
A
- used to have largest amount of lab animals
- important for resarch
2
Q
US Lab Animals
A
- 20M lab animals used per yr
3
Q
US Animal Fatality Causes
A
- # 1 = use of animals for human consumption
- # 2 = roadkill (360M)
- # 3 = hunting
- relatively small amount of animals used for research, but still significant
4
Q
Why Rodents
A
- docile, easy to handle
- mammals
- short generation interval, high prolificacy/fecundity/litter size
- a lot of genetic mutations/mouse genome sequenced very early on
- cheap (housing, higher stocking density, less real estate required)
- once mice used as established model, continued to be mainstay of research (once investigator uses it for research, people use that as basis for future research)
5
Q
Mice Class
A
- Mammalia
6
Q
Mice Order
A
- Rodentia
7
Q
Mice Family
A
- Muridae
8
Q
Mice Subfamily
A
- Murinae
9
Q
Mice Genus
A
- Mus
10
Q
Mice Species
A
- house mouse: Mus musculus
11
Q
House Mouse Chromosomes
A
- 40
12
Q
Dental Formula
A
- 1/1, 0/0, 0/0, 3/3
- only 1 pair of incisors and 3 pairs of molars
- no canines or premolars
13
Q
Malocclusion
A
- overgrown teeth
- mouse teeth grow at 2 mm per week
- need access to gnawing things extensively to prevent malocclusion
- “rodent” = “rodentaire” = “to gnaw”
14
Q
Mouse Diet
A
- omnivorous in wild, plant-based in lab
- economic
- plant-based diet also quality controlled to avoid more things messing up your experiment and standardize diets among different research
15
Q
Digestion and Diet
A
- monogastric
- cecum
- coprophagic (eating feces to access vitamins)
- 10% of diet is feces
- ingest feces 6+ times per day
- means of transferring microbes between individuals (eating each others’ feces –> gut microbiomes reflect the other’s)
- study on making mice deficient in folic acid had to kill off folic-acid producing microbes first bcs mice would just eat feces and get folic acid
16
Q
Nude Mouse
A
- no hair
- athymic nude mouse
- thymus organ grows immune cells
- natural mutation in these mouse made them not have an immune system (no functional thymus, don’t make t-cells, no immune response)
- used to compare effects of pathogens on mice w/ immune system vs athymic mice
- also used bcs they don’t reject transplants from other species
17
Q
Antigen
A
- molecule to which antibody is raised w/in or made w/in your body
- vaccines put antigens in body, body develops immune response, and antibodies are formed that recognize those antigens
- nude mice can’t make antibodies
- can transplant human tissues/tumors into mouse; mouse won’t reject transplants bcs no immune system
- can change mouse diet, drugs, lifestyle to see what helps
18
Q
Ob Mouse
A
- Ob = obesity
- use of genetic mutations/studying genetic basis for disease
- have mutation that means they can’t produce leptin
- mice won’t stop eating and get obese
- important for studying bio of fat synthesis and brain regulation of food intake
- important due to current obesity epidemic
19
Q
Leptin
A
- produced by fat cells
- tells body when to stop eating once energy needs have been overstepped
20
Q
Mouse Mammary Tumor Virus (MMTV)
A
- cancer-causing virus that helps us understand human cancer-causing viruses (hepatitis, HPV)
- mouse w/ MMTV tumor had pups
- pups who drank milk from that mouse had the virus and the tumors
- virus is shed in milk (pups w/out that milk were tumor-free)
- discovery of virus particles, and their passage/shedding studied
21
Q
California Mice Species
A
- Peromyscus californicus
- native to CA
- monogamous
- important in understanding brain dev/behavior and fidelity (why individuals commit to each other)
22
Q
C57/B16 Mice
A
- strain of Mus musculus
- voluntarily consumes alcohol
- used to understand disease, alcoholism, physiology, susceptibility to obesity on different types of diets
- syngeneic/inbred strain
23
Q
Balb/c Mice
A
- strain of Mus musculus
- albino
- sensitive to carcinogens
- Prop 65 warnings - chemicals tested, often on mice, that have been shown to cause cancer
- syngeneic/inbred strain
24
Q
Carcinogens
A
- chemicals or insults (radiation) that cause cancer
25
Inbred or Syngeneic
- populations with individuals who are genetically identical to each other
- important for histocompatibility (no rejection of tissues)
- basis for understanding immune system (no rejection of cross-shared/transplanted specimens among genetically identical organisms)
- also means that any phenotypic variation is due to environmental factors bcs genotype/genome is fixed/identical/standardized among the subjects
- no variability during breeding (no need for Punnett squares)
26
Nocturnal Behavior
- in behavior and breeding
- for mice in colony, light is manipulated and controlled so that they have dark cycle that they can be active during
27
Mice Puberty
- 5-6 weeks
28
Mice Estrous Cycle
- 4-5 days
- can be synchronized using Whitten effect and/or Lee-Boot effect
29
Whitten Effect
- bedding from male housing is soaked w/ urine and the male pheromones bring all the females into estrus 3 days later
30
Lee-Boot Effect
- group-housing females synchs them up into persistent diestrus
31
Polyestrous
- mice are polyestrous and cycle throughout the year
- even though they are in enclosed housing with no external windows/natural light, they are sensitive to day length and weather
- slightly better breeders in spring
- very sensitive body clock
32
Mating System
- harem
- one male breeding multiple females
33
Coital/Seminal Plug
- plug of seminal material left at external part of vulva (large, hard, crusty, white)
- check females every morning for seminal plug to determine if they have been inseminated and predict pregnancies
34
Mice Gestation
- 18-20 days
35
Mice Litters
- pups
- size of litter depends on strain and number of parities (pregnancies) that female has had
- 6-16+ pups
36
Bruce Effect
- introduce another male to pregnant female to stimulate abortion
- how to get rid of unwanted pregnancy or synch female mice
- Bruce effect blocks progesterone activity --> abortion --> restarts cycle
37
Mice Weaning
- 21 days
38
During Lactation
- no lactational anestrous in mice (can keep cycling while lactating)
- can be rebred 1-2 days after giving birth
- why mice can be pests quickly
39
Pup Thermoregulation
- pups are unable to thermoregulate
- mice crouch over their pups to warm them
- pups break down brown adipose tissue to generate heat (common in other species with undeveloped young)
40
White Adipose Tissue
- typical fat tissue (like in meat marbling, etc.)
41
Brown Adipose Tissue
- very active mitochondria that breaks down the brown adipose cells and releases heat
- important for thermoregulation
42
Pup Development
- hair formation: 2-4 days
- eyes open: after 16 days
43
Genetic Manipulation
- mice key for this research
- modifying genome of an individual
- done in rodents to mimic human diseases
- a lot of diseases have genetic mutation component (breast cancer, ovarian cancer, dwarfism
- can rebuild those genetic mutations in mice
44
Transgenic Individual
- take gene from another organism and transfer into a mouse
- might want to produce a protein in that mouse and ask what happens
- might transfer cancer-causing genes (MMTV)
- might transfer things like GFP gene
- might knock out a gene
- CRISPR
45
Green Fluorescent Protein (GFP) Gene
- won Nobel Prize for this research
- at bottom of ocean, jellyfish w/ UV light shined on them glowed green
- scientists found that gene and put it into other organisms (mice) to make fluorescent protein appear in other organisms
46
Knockout Mouse
- knock out a gene from a genome of a mouse and see what happens
- have knocked out Growth Hormone (GH) protein gene, which is responsible for bone growth, size incr, etc.
- knockout mouse much smaller
47
Genotypes for Knockout Mice
+/+ = wild type/normal (homozygous; no modifications/missing alleles
-/- = knockout (homozygous; both alleles have been removed)
+/- = heterozygous (1 normal allele, 1 missing allele
48
CRISPR
- molecular scissors
- can cut out or add in pieces of DNA
- can modify single nucleotides (A, T, C, G)
- very efficient (used to have to put DNA in blastocyst to genetically engineer mice - time-consuming, laborious, expensive)
- CRISPR more precise, fast, cheaper
- can use in a bunch of different species
- has been purified from bacteria and then used to modify organisms (CRISPRed cows that grow without horns)
49
Research Regulations
- regulated by oversight committees
- IACUC = Institutional Animal Care and Use Committee
- anyone that receives gov't money for research is regulated by IACUC
IACUC protocol = documents that outline animal use for research and education
- justify animals being bred, handled -- has to be for greater good/purpose; has to keep animal welfare in mind
