Download Stereoscopic microscopes

KONKUK UNIVERSITY
DEPT. OF ENVIRONMENTAL ENGINEERING
INTRODUCTION TO
MICROBIOLOGY LABORATORY
Dr. Paul
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INTRODUCTION TO MICROBIOLOGY LABORATORY
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Lab Safety
LABORATORY RULES AND PROCEDURES:
Everyone must wear a lab coat or lab apron while in the laboratory.
Do not work with an uncovered open cut.
Keep all sources of possible contamination out of your mouth--hands, pencils, laboratory ware,
other items.
Do not smoke or eat in the laboratory.
Spills of materials containing viable organisms should be immediately contained with dry paper
towels. The dry towel will soak up the spill and can then be sterilized. Following this, the area of the
spill should be disinfected with bench disinfectant.
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Report accidents, such as a spilled culture or a cut, to the laboratory instructor. Our interest is
safety.
Shoes must be worn at all times in the laboratory.
Observe aseptic technique at all times when dealing with microbial cultures.
Wash hands with soap and water or disinfectant before leaving the laboratory.
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INSTRUMENTS & APPARATUSES
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Microscope
microscope is an instrument for viewing objects that
are too small to be seen by the naked or unaided eye.
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Microscopes allow magnified images of illuminated specimens to be
viewed using 2 lenses (an objective and an eyepiece lens). Microscopes that
use two lenses are called compound microscopes.
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TYPES OF MICROSCOPES
Upright microscopes are used for viewing slide glass preparations. Inverted microscopes are
used for viewing petri dishes or culture containers.
Stereoscopic microscopes These microscopes show the specimen three dimensionally
Stereoscopic microscopes
Upright microscope
Inverted microscope
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Microscopy imaging techniques
The most commonly used microscopy imaging technique is brightfield
microscopy, where light is either passed through or reflected off a specimen.
However, there are also techniques known as darkfield microscopy, phase contrast
microscopy, differential interference contrast (DIC) microscopy, fluorescence
microscopy, and polarizing microscopy. Each of these methods is best suited for
different uses.
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Brightfield microscopy Observation is made by viewing the light passed through or
reflected off a specimen.
Main uses:
Viewing stained specimens
Pathological exams
Blood tests
Wafer inspections
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Darkfield microscopy
A special condenser lens is used to illuminate the specimen diagonally, then
observe light scattering off it. The field of view is darker than brightfield
microscopy because illumination light does not enter the objective lens.
Main uses:
Microbiological imaging
Blood tests
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Phase contrast microscopy
The optical phenomena of diffraction and interference are used to add light/dark
contrast to a transparent specimen for imaging. There is no need to stain the specimen as
in brightfield microscopy, so live specimens can be used.
Under bright-field the bacteria would
be exceedingly difficult to see in this
particular situation, yet
phase contrast reveals them with ease
Bacilli in pond water with unidentified algae
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Fluorescence microscopy
Specimen is excited with a specific wavelength of light, then fluorescent
emanations are observed.
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PETRI DISH
INOCULATION LOOP
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Bunsen burner
FLAMING ALOOP
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INCUBATOR
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INCUBATOR
In microbiology, an incubator is a device for controlling the temperature, humidity,
and other conditions in which a microbiological culture is being grown. The
simplest incubators are insulated boxes with an adjustable heater,
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As for temperature, most commonly used is approximately 36 to 37 degrees Celsius. Most
bacteria, especially the frequently used E. Coli, grow well under such conditions. For other
experimental organisms, such as the budding yeast Saccharomyces cerevisiae, a growth
temperature of 30 °C is optimal.
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AUTOCLAVE
HOT AIR OVEN
Laminar flow cabinet
Cell Counts by Hemocytometer
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9 large squares – 1mm x 1mm

Center square divided into 25 smaller squares - 0.2mm x 0.2mm = 0.04 mm2
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Depth of the counting chamber – 0.1 mm

Volume of a small square – 0.04 mm2 x 0.1 mm = 0.004 mm3

1 ml = 1 cm3 = 1000 mm3 (10 mm = 1 cm)
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Average # of cells in a small square X 25
0.1 mm3
Average # of cells in a small square X 25 X 10
1mm3
Average # of cells in a small square X 25 X 10 X 103
1 ml
25
40x magnification
1 mm
100x magnification
0.2 mm
400x magnification