What are some important experiments that have involved lab mice?
Below are some significant experiments that have involved lab mice over the years, and their impact on the scientific world The first experiments on mice were performed by Fredrick Griffith, in 1928. He injected mice with various strains of deadly bacteria, in an effort to distinguish DNA from other proteins and bacterial elements.
How are mice being used in medicine?
Mice have been used to develop the next generation of medical treatments. Using hollow nanometre-sized particles of silver to deliver DNA into the cells of mice, scientists have managed to reverse some of the symptoms of haemophilia.
Which antibiotics can be used to control gene expression in mice?
The antibiotics studied were doxycycline, which typically is administered for the control of gene expression in genetically manipulated mice, and TMS, amoxicillin, and enrofloxacin, which are broad-spectrum antibiotics that have been added to the drinking water of mice.
What do scientists do with mice in germ-free conditions?
In one experiment, scientists raised mice in germ-free conditions so the mice lacked intestinal microbes. The mice were fed a low-fat diet rich in the complex plant polysaccharides, such as cellulose, that are often called fiber.
How to raise and maintain mice free from pathogenic gram-positive bacteria?
To raise and maintain mice free from pathogenic gram-positive bacteria, research and resource staff must employ husbandry and handling procedures that minimize contact with contaminated fomites.
What is the microbiome of a mouse?
Of principal concern is the mouse microbiome, defined as being all of the bacterial species found in, or on, the mouse, and the interactions of those bacteria amongst themselves and with their environment [1]. The human microbiome is estimated to consist of ten times as many cells as the human host.
What is clinical expression of infection?
Clinical expression of infection is typical of pyogenic disease, with clinical signs that range from localized conjunctivitis and dermatitis to fulminate septicemia. Treatment of infections is often instituted to salvage valuable mutant mice until studies are concluded or mice can be rederived.
What causes sporadic infections in mice?
Gram-positive bacterial infections in mice are among the most common causes of sporadic infections in research colonies, but the lack of recent reports of disease under represents disease prevalence in contemporary research facilities.
How long is a bacillus?
Most often, it appears as a long, slender (i.e. hair-like or piliform) bacillus, approximately. 8 – 10 m m long and 0.5 m m wide, in the cytoplasm. of infected cells, although shorter, thicker, cigar-shaped forms may also occasionally be. seen. Considered non-cultivable on artificial.
Do mice have clostridia?
It may be that laboratory mice lack suitable receptors for bacterial attachment that are expressed on cells of host species that are susceptible to infection. Less than 20 species of clostridia are associated with disease in animals .
Is S. cuniculi a mouse?
We suggest S. cuniculi is an opportunistic bacteria in laboratory mice but are uncertain of its source. Our findings revealed that S . cuniculi is able to colonize laboratory mice and should be considered when mice present with eye lesion or ocular discharge. ...
What did the mice eat?
The mice were fed a low-fat diet rich in the complex plant polysaccharides, such as cellulose, that are often called fiber. When the mice were 12 weeks old, the scientists transplanted the microbial community from the intestine of a single "donor" mouse into all of the germ-free mice.
Why do Gram negative bacteria appear red?
Gram-negative bacteria appear red or pink because the alcohol rinse washes away the crystal violet dye.
Why are Azotobacter pink?
They are shaped like rods. Azotobacter is a genus of rod-shaped bacteria (bacilli). After Gram staining, bacteria in this genus appear pink due to the thin peptidoglycan layer in their cell wall.
What is Gram staining?
Gram staining is a technique for classifying bacteria based on differences in the structure of their cell walls. Gram-negative bacteria and gram-positive bacteria both have a plasma membrane surrounded by a cell wall that contains peptidoglycan.
Why do Gram positive bacteria turn purple?
Gram-positive bacteria appear purple because the alcohol rinse does not wash away the crystal violet dye. Click again to see term 👆. Tap again to see term 👆. Label the diagram below to show the relationship between nutritional modes of bacteria. Drag the labels to their appropriate locations on the diagram.
What is the carbon source of an autotroph?
Autotrophs (literally "self-feeders") require only an inorganic substance, such as carbon dioxide, as their carbon source; heterotrophs (literally "other-feeders") require at least one organic nutrient as their carbon source.
What are autotrophs and heterotrophs?
Autotrophs (literally "self-feeders") require only an inorganic substance, such as carbon dioxide, as their carbon source; heterotrophs (literally "other-feeders") require at least one organic nutrient as their carbon source. Nice work! You just studied 21 terms! Now up your study game with Learn mode.
How to do Kirby Bauer antimicrobic sensitivity test?
Place the steps of the Kirby Bauer method of antimicrobic sensitivity testing in the correct order. 1.Label a sterile Mueller-Hinton agar plate with organisms name and your name. 2.Obtain a dilute suspension of the organism in nutrient broth to use as the inoculum. 3.Using a swab, inoculate the agar plate uniformly by swabbing in three directions.
Where is the bacterial isolate incubated?
A bacterial isolate is subcultured to two blood agar plates, one of which is incubated in an anaerobe jar, and the other is incubated on a shelf in the incubator. After incubation, growth is observed on the plate from the anaerobe jar, but there is no growth on the plate incubated on the incubator shelf.
What is the difference between disinfectant and antiseptic?
An antiseptic is used to remove or kill microorganisms on tissue, whereas a disinfectant is used to remove or kill microorganisms on inanimate objects. You have placed cultures in an anaerobe jar, activated the gas pack, and sealed the jar.
How to test for disinfectant effectiveness?
Place these steps in the order in which they will be performed when setting up a disk diffusion assay to test the effectiveness of disinfectants and antiseptics. 1.Using a swab, inoculate a suspension of the bacteria being tested onto an agar plate, spreading the inoculum over the entire surface. 2.Saturate sterile filter paper disks with ...
What is the Kirby-Bauer test?
Kirby-Bauer test. A chemical compound, regardless of its source (either natural or synthetic), that is capable of killing or inhibiting microorganisms is referred to as: an antimicrobial. The clear area devoid of bacterial growth around an antiseptic or disinfecant disk is referred to as the. zone of inhibition.
What is a stainless steel surface in biological safety cabinet used for media preparation?
A bacterial species that cannot tolerate the presence of oxygen and will only grow in the absence of oxygen is classified as a(n): obligate anaerobe.
Who was the first scientist to use mice?
The first experiments on mice were performed by Fredrick Griffith, in 1928. He injected mice with various strains of deadly bacteria, in an effort to distinguish DNA from other proteins and bacterial elements. His methods became widely known, as scientists still use mice today in laboratory testing.
How do mice help with haemophilia?
Mice have been used to develop the next generation of medical treatments. Using hollow nanometre-sized particles of silver to deliver DNA into the cells of mice , scientists have managed to reverse some of the symptoms of haemophilia. Gene therapy such as this can compensate for the effects of diseases caused by mutated DNA by delivering a "correct" copy of the genetic material to a site in the body.
Why do rats and mice have similar addictions?
Because the human and mouse brain are so similar in the way they perceive 'pleasure' , determining the genes responsible for these differences in drug or alcohol tolerances could help scientists discover how to help a human better recover from an addiction.
What was the role of nitrogen mustard in leukemia?
This led to chemical agents, such as nitrogen mustard, being identified for causing tumours. It also helped scientists to isolate potential anti-leukemia agents.
Can mice be used as guinea pigs?
This is a relatively new development in science, only coming to public light last year. It is now possible to give a mouse part of a patient's disease, so that the mouse can serve as the patient's personal guinea pig, so to speak. These 'mini-me' versions of a human's condition allow scientists the opportunities to test drugs on the mice counterparts, to find out which ones will be efficacious, without exposing the patient to any toxicity. If a drug is effective at helping the mouse, there is a high chance that the human will benefit as a result of the drug as well. The 'copy' mouse can also develop cells that correspond to the patient's cells, for example,"personalized immune mice" might produce immune cells that can be transplanted into a human patient to help fight disease.
Why are control groups important in drug trials?
Oftentimes, control groups in drug trials consist of people who also have the disease or ailment, but who don’t receive the medicine being tested. Instead, to keep the control group the same as the treatment groups, the patients in the control group are also given a pill. This is a sugar pill usually and contains no medicine. This practice of having a control group is important for drug trial, because it validates the results obtained. However, the control groups have also demonstrated an interesting effect, known as the placebo effect
What is the scientific method?
Scientific Method – The steps scientist follow to ensure their results are valid and reproducible. Placebo Effect – A phenomenon when patients in the control group experience the same effects as those in the treatment group, though no treatment was given.
What is a control group?
Control Group Definition. In scientific experiments, the control group is the group of subject that receive no treatment or a standardized treatment. Without the control group, there would be nothing to compare the treatment group to. When statistics refer to something being “X times more likely to happen” they are referring to ...
Can a variable be removed from a control group?
Sometimes, the variable cannot be removed from the control group, and it must be standardized. A population of mice has an average level of protein in their blood of 10. Increased or decreased protein levels affect the functions mice are able to perform.
Can rats eat strawberries?
A group of rats that gets some strawberries, and a normal diet. B is correct. The group of rats that gets no strawberries will be able to show researchers what rats look and behave like without strawberries. Researchers can test their feces for signs of digestive processes, stress and other signs of health.