MODULAR APPROACH FOR MICROBIOLOGY LABORATORY
BY: CARMONA, DIVINAGRACIA, NERI, VELASCO, VITUG
ACTIVITY 1 LABORATORY SAFETY PROCEDURES, MICROSCOPY AND
MICROMETRY OF PREPARED SLIDES
I.
Objectives
At the end of this exercise, the student should be able:
a. To demonstrate safety procedures when handling infectious agents
b. To learn sterile handling of equipment and materials for use in microbiological
procedures.
c. To familiarize students with the parts and function of microscopes
d. To acquire skills in handling and using a microscope
e. To understand the mechanism on how the microscope works
II.
Introduction
Laboratory biosafety is an important concept in microbiology workflow which would
provide protection against potential infections laboratory personnel as well as to avoid
contamination of the biological materials being handled. There are guidelines needed
tofollow to maintain safety in the laboratory and protect user from harmful incidents.
The microscope is an instrument essential to every biologists. It had produced
significant contributions in Science by unearthing the world of microorganisms and the
study and discovery of cells to name a few. It helped expand and deepen the knowledge of
scientists by seeing more details in an object through enlarging images.
There are several types of microscope, the most common is the compound
microscope. It utilizes series of lenses of glasses to concentrate light through or onto the
object. The convex objective lenses, makes the object appear bigger. The images are mostly
viewed in the eyepiece binoculars of a microscope that gives additional magnification and
acts like a magnifying glass.
III.
Learning Platform
a. Modified Microbiology Laboratory Activity
b. Biosafety cabinet
https://www.youtube.com/watch?v=96-aZLom340
c. Personnel Protective Equipment
https://www.youtube.com/watch?v=oO5Awp5LCNg
d. Microscopy
https://www.youtube.com/watch?v=3LIZBn7bS4s
https://www.youtube.com/watch?v=t4hhdgJADE8
https://www.youtube.com/watch?v=SUo2fHZaZCU
e. Micrometry
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MODULAR APPROACH FOR MICROBIOLOGY LABORATORY
BY: CARMONA, DIVINAGRACIA, NERI, VELASCO, VITUG
https://www.youtube.com/watch?v=HaqgCtA-ioI
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MODULAR APPROACH FOR MICROBIOLOGY LABORATORY
IV.
BY: CARMONA, DIVINAGRACIA, NERI, VELASCO, VITUG
Materials
laptop or desktop computer with internet connection
drawing materials: pencil, eraser, gel pen, coloring pencils/crayons
V.
Procedures
A.
Biosafety Cabinets
1. Watch the provided Youtube links on biosafety cabinets:
https://www.youtube.com/watch?v=96-aZLom340
2. Answer laboratory worksheet.
B. Personnel Protective Equipment
1. Watch the provided Youtube links on personal protective
equipment:
https://www.youtube.com/watch?v=oO5Awp5LCNg
2.
Answer the laboratory worksheet.
C. Microscopy
1. Watch the provided Youtube links on microscopy:
https://www.youtube.com/watch?v=3LIZBn7bS4s
https://www.youtube.com/watch?v=t4hhdgJADE8
https://www.youtube.com/watch?v=SUo2fHZaZCU
2. By using a virtual microscope, observe bacterial cells stained with different
dyes:
https://www.ncbionetwork.org/iet/microscope/?fbclid=IwAR3n_RqERmIDzRNYM
3-rgVpJLRzzVOfHC1vwV9Q0RCosaM_5s6uVkNVOPoA
3. Answer the laboratory worksheet.
D. Virtual Laboratory Procedures on Micrometry
1. Insert the ocular micrometer (OM) into the circular shelf of the microscope
containing the eyepiece. Firstly, remove the ocular lens before inserting the
micrometer. Then replace back the ocular lens in the microscope. On the
microscope stage, mount the stage micrometer.
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MODULAR APPROACH FOR MICROBIOLOGY LABORATORY
BY: CARMONA, DIVINAGRACIA, NERI, VELASCO, VITUG
2. Center the scale of the stage micrometer (SM) with the low-power objective.
Then, observe the micrometer under the OIO. Note that the stage micrometer
has a carefully calibrated scale which is divided into 0.1 mm and 0.01 mm units.
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MODULAR APPROACH FOR MICROBIOLOGY LABORATORY
BY: CARMONA, DIVINAGRACIA, NERI, VELASCO, VITUG
3. Rotate the micrometer until the lines of the ocular micrometer are
superimposed on the lies of the state micrometer. Starting from these
coinciding lines, count the spaces of both the stage and the ocular
micrometers until the lines of the micrometers coincide again.
Source: http://ibg102group1.blogspot.com
As shown above, using your 100x objective (as an example), 10 divisions
on the ocular micrometer scale equal 0.01mm on the stage micrometer. Hence,
each small division on the ocular micrometer=1μm. Distance between ocular
micrometer divisions is different for each objective. Calibration of each objective
with the stage micrometer, is, therefore, important.
Calculate then the calibration factor for the OIO.
SM
(mm) =
OM
1000µm = µm per ocular unit
mm
4. Replace the stage micrometer with any of the provided stained cells. Measure the cell
diameter or cell length or dimension using the calibrated ocular micrometer. Express the
dimension in micrometer (μm). Record your result.
NOTE: The calibration is done for each objective (LPO, HPO and OIO). It is the
ocular micrometer that is calibrated against the stage micrometer that is used in
measuring cells or other microscopic objects.
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MODULAR APPROACH FOR MICROBIOLOGY LABORATORY
BY: CARMONA, DIVINAGRACIA, NERI, VELASCO, VITUG
LABORATORY WORKSHEET 1
Name: _______________________________________
Instructor: ____________________________
Year and Section: ____________________________
Score: _________________________________
Guide Questions: Laboratory Safety
1. What are the differences between the biosafety levels?
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2. Enumerate the basic PPEs for a BSL-2 lab.
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3. Enumerate biosafety equipment typically used in the lab. Discuss.
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4. What safety protocols must be present in a COVID-19 laboratory testing facility?
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MODULAR APPROACH FOR MICROBIOLOGY LABORATORY
BY: CARMONA, DIVINAGRACIA, NERI, VELASCO, VITUG
Guide Questions: Microscopy
1. What is the difference between magnification and resolution?
 Magnification
2. Enumerate the different types of microscopes and discuss their uses. Tabulate your
answers.
Types of microscopes
Uses
3. Label the parts of the microscope.
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MODULAR APPROACH FOR MICROBIOLOGY LABORATORY
BY: CARMONA, DIVINAGRACIA, NERI, VELASCO, VITUG
4. What are the functions of each part of the microscope? Tabulate your answers.
Part of microscope
Function
5. Open the NCBioNetwork Microscope Simulation and explore the bacterial slides for Acid Fast Mix,
Endospore Stain and Gram Stain Mix. Draw the microscopic views of the slides under 40x and
100x magnification.
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MODULAR APPROACH FOR MICROBIOLOGY LABORATORY
Figure 1. (Name of the specimen) under 40X
BY: CARMONA, DIVINAGRACIA, NERI, VELASCO, VITUG
Figure 2. (Name of the specimen) under 100X
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MODULAR APPROACH FOR MICROBIOLOGY LABORATORY
BY: CARMONA, DIVINAGRACIA, NERI, VELASCO, VITUG
Figure 3. (Name of the specimen) under 40X
Figure 4. (Name of the specimen) under 100X
Figure 5. (Name of the specimen) under 40X
Figure 6. (Name of the specimen) under 100X
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MODULAR APPROACH FOR MICROBIOLOGY LABORATORY
BY: CARMONA, DIVINAGRACIA, NERI, VELASCO, VITUG
Activity for Microscopic Measurement
Legend:
Red: Stage micrometer
Black: Ocular micrometer
1. Show your computation for the calibration factor (CF).
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MODULAR APPROACH FOR MICROBIOLOGY LABORATORY
BY: CARMONA, DIVINAGRACIA, NERI, VELASCO, VITUG
2. Measure the cell size (Magnification: 40x)
Show your computation.
3.
Measure the cell size (Magnification 100x).
Show your computation.
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MODULAR APPROACH FOR MICROBIOLOGY LABORATORY
BY: CARMONA, DIVINAGRACIA, NERI, VELASCO, VITUG
7. How does true microbial motility distinguish from other kinds of motion like Brownian
movement that can be seen under microscope?
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______________________________________________________________________________________________________
______________________________________________________________________________________________________
8. What is the function of immersion oil in the OIO.
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Conclusion
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References
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