Macroeconomics

3… ASEPTIC TECHNIQUE IN VUMICRO™ 3.11 The goals for this exercise are : • to become familiar with the parts and features of the Virtual Lab • to become familiar with the means by which asepsis is recreated in the Virtual Lab and by which aseptic technique is simulated in VirtualUnknown™ Microbiology • to become familiar with means by which proficiency in aseptic technique can be communicated to the instructor through the Virtual Lab Report. • to allow students opportunity to practice “wetlab” techniques beyond the limitations of time and space imposed by access to the wetlab. Instructions : 1. Open the software. Work through the Tutorial to become acclimated to the means by which the Virtual Lab functions . Once you feel comfortable with the workings of the lab, exit the Tutorial and enter the Virtual Lab. Create a new unknown named “GPOS”, using “Gram Positive Coccus” as the “exercise topic or subgroup” (refer to Exercise 1, step 4 for instructions on how to create an unknown) . For this exercise, DO NOT check the box permitting auto- inoculation. 2. Read through the Case Study and interpret the Gram stain. Obtain a tube of phenol red glucose broth with Durham tube and provide an identifying label – prgb. Appearing will be two tubes – one at left which is your culture of unknown organism and the one at right which is sterile phenol red glucose broth. 3. The purpose of aseptic technique is to control the conditions of the work environment so that sterile conditions and media remain that way until inoculated deliberately by the lab worker. The two tubes represent the “before” and “after” results when this is accomplished – a sterile medium and a pure culture of the unknown organism. List three precautions taken in the wetlab to reduce accidental inoculation (also known as “contamination”) of sterile media. Put a Label on every item, Wear proper gloves and use a lab-coat when in the lab, Keep all equipment and materials sterilize, disinfect all waste material, and clean up if there are any spills but with precaution. 17 Basic Training Manual for VUMicro™ 3.11 Name:_ Copyright © 2003-2005, Intuitive Systems, Inc. Section:_ 4. Note the traffic signals in the upper right corner. Be sure to have at your disposal a timekeeping device (watch or clock). Remove the caps from the tubes (by selecting that option following a right-click on the sterile tube at right) and begin timing. How long a time period is provided for users of VUMicro™ 3.11 before the Contamination light turns red ? The time period was two minutes NOTE: The steps needed to complete an aseptic transfer with VUMicro™ mirror those used in the wetlab. To review how to accomplish these steps using the software, review the “Tutorial” or “Tell Me More About Aseptic Transfers” in “Help”. 5. Replace the caps on those tubes, then drag the phenol red glucose broth tube and drop it in the 37 o C incubator. Immediately retrieve the medium from the incubator by right-clicking on it and selecting the medium. Explain why a contaminated culture has not demonstrated any observable change at this point ? I didn’t find any changes since it wasn’t incubated for enough time. 6. Replace the contaminated tube into the incubator. Click “New Day”. Retrieve the medium from the incubator. What does the turbidity and color change of the medium indicate ? It indicates that the bacterial numbers are increasing because it turned yellow. 7. Did you intentionally inoculate the medium ? Interpret the meaning of these results and predict the source of the inoculum . Yes, I did inoculate the medium, in order to find out how quickly it would take for the experiment to get contaminated. I believe the reason for contamination could have been from dust or any other particles found in the air. 8. Do these results faithfully reflect what would be expected in the wet lab ? Why does it make sense that contamination leads to a positive result in every case ? It makes sense because it reflects the things that could happen in a wet lab. One of the main important things is to always work in a well- sanitized lab for best experiment results. 18

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