What is slant culture?
An agar slant tube (or simply an agar slant) is a screw-capped culture tube partly filled with an agar mix such as nutrient agar, R2A agar, or TSA (figure 1). To make it a slant tube the agar is allowed to cool with the tube laying at an angle, resulting in a large surface area for spreading a culture.
What does clamshell the plate mean?
opening as agar plate
What is the purpose of the clam shell technique microbiology?
The “Clamshell” Technique Allow the agar to solidify and cool-down (approximately 15 minutes).
Why do we Flame the loop between streaks?
Flaming the loop between streaks ensures that the loop starts clean and that only this small amount of bacteria is used to inoculate the next quadrant.
How do you streak a plate with bacteria?
- Hold loop with bacterial sample parallel to fresh plate.
- Gently rub loop across surface spreading bacteria thinly throughout.
- Flip loop on other side or even gently drag edges across plate if visible bacteria still needs to be delivered.
What is the difference between a broth and a slant?
Answer and Explanation: Pure broth cultures contain a liquid media, while slant cultures contain a semi-solid media.
Why is it important to use a sterilized loop between streaks when preparing a streak plate?
Flame the loop or use a new disposable loop after you streak each quadrant. Using a new or sterilized loop allows you to effectively dilute the inoculum on the plate and obtain isolated colonies by spreading the inoculum thinner and more evenly.
What advantages does the streak plate method have over the pour plate method?
What advantage does the streak plate method have over the pour-plate method? The streak plate method does not require any additional media for dilution and only requires one plate for inoculation.
How can you tell if a streak plate is contaminated?
If some of your agar plates become contaminated, you can often tell by examining the plate how contamination took place. If the contaminants are imbedded in the agar, the contaminant was probably poured with the medium.
How can a streak plate become contaminated?
How can a streak plate become contaminated? If the loop is not sterilized. If you drop the plate. If lid isn’t on.
What is the purpose of a streak plate?
Agar streak plates are an essential tool in microbiology. They allow bacteria and fungi to grow on a semi-solid surface to produce discrete colonies. These colonies can be used to help identify the organism, purify the strain free of contaminants, and produce a pure genetic clone.
What happens if you don’t flame the loop in between quadrants?
What is a bacterial colony? What would happen if you forgot to sterilize your loop in between each quadrant streak? You would spread a lot of bacteria back into quadrant one and probably not see isolated colonies.
Will E coli grow without shaking?
Re: E. coli without agitation. Nope. As long as you KEEP it sterile.
Why should you always mix up a broth culture before using it for the first time?
Bacterial liquid cultures should be shaken always (but not too vigorously), in order to ensure aeration and oxygen and nutrient availability as well as to avoid bacterial settlement on the flask bottom which would result in cell death from the lack of nutrient availability.
What is the most important reason to streak for isolation?
As you might guess, the purpose of streaking for isolation is to produce isolated colonies of an organism on an agar plate. This is useful when you need to separate organisms in a mixed culture or when you need to study the colony morphology of an organism.
Which quadrant houses the least number of bacteria?
Quadrants II and III will have the isolated colonies because they have the least amount of bacteria in them. 1) Pure colonies can be used to start a large stock culture (subculture) of a single isolated bacteria. 2) Can be used to separate and isolate individual species of bacteria from mixed inoculum.
What does streaking mean?
an act or instance of running naked through a public place. television light or dark streaks to the right of a bright object in a television picture, caused by distortion in the transmission chain.
What is the proper way to label plates?
Label around the edge of the bottom (not the lid) of an agar plate with at least your name, the date, the type of growth medium, and the type of organism to be plated on the medium. The plates must be completely dry without condensation on the lid and pre-warmed to room temperature prior to streak-plating.
How do you describe a streak plate?
Streak plate technique is used for the isolation into a pure culture of the organisms (mostly bacteria), from a mixed population. The inoculum is streaked over the agar surface in such a way that it “thins out” the bacteria. Some individual bacterial cells are separated and well-spaced from each other.
What will happen if you incubate the plates incorrectly With the lid on the top?
The water on the agar will create a soupy mess of bacteria instead of isolated colonies. Incubating the plate upside down keeps water condensation in the lid and away from your culture. When a plate is exposed to airborne contaminants, the contaminating microbes settle all over the plate.
What happens if you incubate bacteria too long?
If a bacterial culture is left in the same media for too long, the cells use up the available nutrients, excrete toxic metabolites, and eventually the entire population will die. Thus bacterial cultures must be periodically transferred, or subcultured, to new media to keep the bacterial population growing.
How do you make a streak plate for bacteria?
You can make streak plates of bacteria or yeasts. A streak plate involves the progressive dilution of an inoculum of bacteria or yeast over the surface of solidified agar medium in a Petri dish. The result is that some of the colonies on the plate grow well separated from each other.
Can bacteria grow on a streak plate?
After incubation, bacterial growth is visible as colonies in and on the agar of a pour plate. Can some bacteria grow on the streak plate and not be seen if the pour plate technique is used? Yes, the pour plate is O2 limited. Thus, some bacteria will only grow on the streak plate as it provides ample O2.
What is a slant used for?
Agar slants are commonly used to generate stocks of bacteria. Agar plates can be used to separate mixtures of bacteria and to observe colony characteristics of different species of bacteria (you will perform an experiment in this lab to illustrate this).
In which quadrant will we find the most bacteria?
What is the difference between streak plate and spread plate technique?
The key difference between streak plate and spread plate is that the streak plate is used to isolate and purify a particular bacterial species from a mixture of bacteria while the spread plate is used to enumerate and quantify bacteria in a sample.
Why do you want to close the lid of the tube when you are finished using it?
Airborne bacteria may fall anywhere on this slant and grow to form a colony. Why should the lid should partially cover the plate while the student is removing inoculum? This technique prevents airborne microbes from contaminating the surface of the agar.
Why do we put the plates in the incubators at 25 C and not higher?
Health & Safety and Technical notes 2 Keep plates at room temperature or incubate at 20-25 °C for 2-3 days. Fungi grow more successfully at lower temperatures. Do not incubate at human body temperature (or above 30 °C) – this reduces the risk of culturing microbes that are pathogens to humans.