November 07, 2011

Common Laboratory Techniques

During the course of these laboratory sessions, you will be expected to become proficient in the performance of the following laboratory techniques:
o Isolation of pure bacterial colonies
o Gram stain.
Development of competency in these techniques requires that you also know how to:
o Flame a loop
o Streak a plate for isolated colonies
o Use a light microscope.
Each person is responsible for his microscope and is expected to clean the oil immersion lens at the end of each lab in which it is used. First-year students share these microscopes and, as you may remember, do not appreciate having to clean the microscope before it can be used.
A short video that will be shown in the first laboratory session will reinforce the microscopic techniques you learned in first-year histology class and remind you of the correct way to use a microscope. It is expected that after the first laboratory session, each student will be able to focus on a stained bacterial preparation, find and identify the bacteria present on the slide. Students who do not feel comfortable using the microscope should ask for help from their sector instructors. Each microscope was cleaned and adjusted before the start of the course. If your microscope is not functional, report it to Julie Tippett in Student Affairs Office immediately after the laboratory session. Each student will need a functional microscope for each lab and to complete the final exam. You will not be given help in focusing your microscope during the final examination.  

Remember that bacteria are always viewed using the oil immersion lens (the 100X objective, which requires the use of oil). The high power objective (not oil immersion) will be used for the study of fungal morphology in Lab 5.
The methods on the following pages will be a useful reference for each laboratory session.