Now you may lay the loop down until it is needed again. Transferring the inoculum to an agar plate: lift the edge of the lid just enough to insert the loop. Test for coolness by touching the agar at the edge of the plate. Pick up a loopful of liquid inoculum or bacterial growth from the surface of an agar plate and, starting about 25 mm in from the edge of the plate 1 , streak lightly back and forth with the loop flat, making close, parallel streaks back to the edge of the plate.
Flame and cool the loop again, and make another set of streaks starting from 3 perpendicular to and crossing the second set of streaks, but avoiding the first set. Username Password Remember Me Lost your password? Remember Me Lost your password?
Aseptic techniques are important in many experiments involving microbial samples from the environment. In this study, researchers isolated bacteriophages, which are bacteria-infecting viruses, from the common soil bacterium Arthrobacter. Arthrobacter cultures were first grown under aseptic conditions.
Soil samples were then washed and filtered in phage buffer, and the phage solution was mixed with the bacterial culture and plated onto agar plates. A bacterial lawn would form on the plate, but there would be clearings, or "plaques", at spots where the virus had infected and killed the bacteria.
Phage could then be purified from these plaques for further study. Other than using Bunsen burners, aseptic working environments can also be maintained in specialized workstations known as laminar flow hoods, which use directed airflow and filters to maintain sterility. Here, scientists worked in a flow hood to isolate potential pathogenic bacteria and viruses from water samples. These isolates were then cultured together with amoebae. Because amoebae normally eat or "phagocytose" bacteria, any bacteria that were able to resist amoebal digestion and remain in these organisms can also potentially remain viable in human cells and cause diseases.
Finally, sterile conditions permit detailed study of ecological mechanisms such as the formation of root nodules in legume plants - bacteria-filled organs that "fix" atmospheric nitrogen into ammonia, which is used by the plant for growth. Researchers here created "microcosms" for studying the nodulation process using notched Petri plates with plant growth medium, placed seedlings into them and inoculated the seedlings with nodule-forming rhizobial bacteria.
The aseptic environment of the flow hood prevents contamination of the cultures with other bacteria or fungi. You've just watched JoVE's video on aseptic techniques in environmental science. You should now understand why aseptic working conditions are important; how to aseptically perform microbiological experiments; and some applications of aseptic techniques to environmental research. As always, thanks for watching! The outcome of the procedure demonstrates proper aseptic technique and poor aseptic technique.
Figure 7 illustrates the contamination that can arise from poor aseptic technique when pouring agarose plates top plate: sterile medium; bottom plates: contaminated media. Figure 7: Contamination that can arise from poor aseptic technique when pouring agarose plates. Top plate: sterile medium; bottom plates: contaminated media. Proper use of aseptic technique is vital for environmental microbiologists when sampling in the field and in the laboratory when working with media, reagents, and cultured isolates.
Poor aseptic technique in the field can result in the transfer of microorganisms from the technician to critical environmental samples, as well as the cross-contamination of microbes from one sample to another. Such events are of importance, for example, in microbial ecology studies seeking to identify and compare bacterial and fungal populations that may be present in a given biome.
Contamination of such samples can result in a loss of data integrity. Aseptic technique is also critical for the maintenance of laboratory culture isolates originating from field sampling or from well-established microbial and cell culture repositories.
Environmental Microbiology. Aseptic Technique in Environmental Science. To learn more about our GDPR policies click here. If you want more info regarding data storage, please contact gdpr jove. Your access has now expired. Provide feedback to your librarian. If you have any questions, please do not hesitate to reach out to our customer success team. Login processing This is a sample clip.
Sign in or start your free trial. Previous Video Next Video. Overview Source: Laboratories of Dr. Charles Gerba - The University of Arizona Demonstrating Author: Luisa Ikner Aseptic technique is a fundamental skill widely practiced in the field of environmental microbiology that requires a balance of mindfulness and practice in the laboratory.
Log in or Start trial to access full content. Preparation for Aseptic Work Obtain and apply the following PPE items: lab coat, latex or nitrile gloves free from tears or holes , and safety goggles Figure 1. For safety in the event of using an open flame, tie back long hair. Figure 1: PPE: A lab coat, latex gloves, and safety goggles.
Prepare liquid broth medium e. For the broth medium, dissolve the powder on a hot plate with low heat applied, and dispense the liquid either in mL volumes into glass screw-top flasks, or in mL volumes into glass screw-top test tubes. Using a magnetic stir bar, stir the agarose medium on the hot plate stirrer until the powder is fully dissolved. Note that the color of stripes on the autoclave tape should change from white pre-autoclave to black post-autoclave.
Isopropyl alcohol 2-propanol , also known as isopropanol or IPA, is the most common and widely used disinfectant within pharmaceutics, hospitals, cleanrooms, and electronics or medical device manufacturing. Begin typing your search term above and press enter to search. Press ESC to cancel. Skip to content Home Social studies Why is it important to flame Sterilize the inoculating loop before picking bacteria up with it why do you flame sterilize the loop again after transferring the bacteria to the slide?
Social studies. Ben Davis September 8, Why is it important to flame Sterilize the inoculating loop before picking bacteria up with it why do you flame sterilize the loop again after transferring the bacteria to the slide?
Which cone of the flame will you use to sterilize the inoculating loop? Why should you never leave your loop or needle in the BACT incinerator? How long does it take to sterilize an inoculating loop or needle? Why must loops be cooled first? Why should the inoculating loop be cooled? Why should inoculating loops are sterilized? SLANT: solid medium made with agar and various nutrients and indicators.
Slanting gives the bacteria a greater surface area on which to grow in a tube. Agar slants are also useful in maintaining bacterial cultures, more so than stacks of Petri dishes.
Multiple cultures are easily placed into test tube racks and stored under refrigeration. Bacteria are inoculated onto a slant using a loop and grow in the surface of the agar. This type of culture medium gives the ability to grow bacteria in both an aerobic, oxygen-rich, environment surface of the slant and an anaerobic, oxygen deficient, environment butt of slant.
DEEP: solid medium made with agar and various nutrients and indicators. This type of culture is used for the growth of anaerobic bacteria which grow in the absence of oxygen and are inoculated by stabbing the media with a needle. BROTH: liquid medium made with various nutrients and indicators. Allows for the growth of large volumes of bacteria, the level of growth can be assessed based on the turbidity cloudiness of the culture. Bacteria are inoculated into a broth using a loop.
Durham tubes are used to detect the production of gases, such as CO2 or N2, by microorganisms.
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