1.1 Setting
up and using the microscope
1.
Introduction
Microscope is two words that came
from “Micro” means tiny and “Scope” refers to view of something that we want to
look at. Therefore, microscopes are tools or optical instruments which having a
magnifying lens or a combination of lenses for inspecting objects too small to
be seen distinctly and in detail by the unaided eyes. There are many types of
microscopes these days and they are used according to the situation and
condition. However, the compound light microscopes are the most common tools
used for viewing microorganisms. It is having more than one lens, and knobs
with variety functions to view the microorganisms.
Diagram 1.1 : Compound Light Microscope
2.
Materials
Microscope slide
Specimen slide
Cover slip
Immersion oil
Marker pen
Lens tissue
3.
Procedures
Low
power (10X) objective viewing:
High
power (40X) objective viewing:
Oil
immersion (100X) objective viewing:
1. One or two drops of immersion oil was put over the specimen slide cover slip for oil immersion (100X) objective viewing.
2. Specimen slide was put on the mechanical stage and was secured by a spring clip.
3. The 100X objective lens was rotated into the light path. The immersion oil was brought into contact with 100X objective lens by the adjustment of coaxial stage control knob to produce a clearer image.
4. The light intensity was adjusted using condenser diaphragm and illumination intensity knob to obtain the optimum brightness.
5. The specimen slide was then removed.
After
use:
Care
of the microscope:
1.2 Examination
of Cells
1. Introduction
In
biology courses you may take in the future, you will need to make extensive use
of microscopes. Much cell biology research still requires careful microscopic
examination of cell and their internal structures. The purpose of today’s
laboratory is to provide you with a through introduction to the care and use of
these precision instruments. Your personal goal should be to become as
comfortable as possible with using microscopes, making sure that you are seeing
the various organisms as well as your microscope will allow. The more important
goal is for you to gain an appreciation for the beauty and variety of microscope
life, but good microscope skills have to be in place before that can happen.
2. Materials
Culture
Immersion
oil
Lens
tissue
A
microscope slide containing stained microorganisms
Inoculating
loop
Bunsen
burner
Slide
and cover-slip
Procedure
Stained
cells:
1. Microscope is set up as described above and
the slide under the oil immersion lens is examined.
2. The shape and size of the organisms and any
structure that visible are observed and drew based on what we see via the
microscope.
The
Wet mount:
1.
A
sterile Pasteur pipette is used to aseptically transfer one drop of culture to
the centre of glass slide.
2.
A
marker pen is used to mark a coverslip. This mark is used to help we focus on
the microorganisms.
3.
The
coverslip is taken and turned so that the marker pen mark faces down. Then one
edge of the coverslip is placed onto the slide and gently lower it so that it
will cover the drop of culture. The culture will spread between the coverslip
and the slide.
4.
The
slide is placed on the microscope stage and 4x objective focus is used on the
culture. Two or three groups of highly motile protozoa will be seen.
5.
The
cell is observed using the 10x and 40x objectives. Some smaller moving object
may be detected when observed it closely. Some of the larger types of bacteria
also can be seen.
6.
The
cells are observed using oil immersion lens. The condenser and diaphragm are
adjusted to get the better and clear image.
7.
The
procedures are repeated with other cultures.
RESULT
Diagram 1.3 : Cocci
Discussion
Lactobacillus
From the picture shown above, we
can see that the Lactobacillus are in rod-shaped, fermentative, non-spore forming
and gram-positive. At certain condition, rod-shaped Lactobacillus may
transformed into spiral or coccobacillary form that is totally different
compared to rod-shaped Lactobacillus. Similar to other genera in the family, Lactobacillus
are able to produce lactic acid which are the by-product from glucose
metabolism. Lactobacillus are commonly in nature and found in association with
many flora and fauna. Commonly, Lactobacillus are non-motile and able to live
in aerobic or anaerobic environment. Lactobacillus organism commonly not so
efficient in metabolism of glucose. They have to derive energy from other
compound such as galactose, fructose and malate. By non-oxidative substrate
level phosphorylation, they can generate ATP to carry out other activities.
Cocci
Referred to the picture, we can see
that Cocci are in spherical, ovoid, or generally round shape. Cocci may occur
as single cells or remain attached following cell division. Those that remain
can be classified based on cellular arrangement. There are Diplococci (pairs of
cocci), Streptococci (chains of cocci), Staphylococci (clusters of cocci just
like grape), Tetrads (cluster of four cocci arranged within the same plane),
Sarcina (bacteria that are found in cuboidal arrangements of eight cocci).
Conclusion
Based on the experiment above, we
can learn on how to use microscope with the right technique and effectively so
we can get a clear image of the microorganisms. We can observe that the
Lactobacillus bacteria is in rod-shaped and Cocci bacteria is in spherical or
generally round shape. However, we still able to found some of them are in
spiral-shape.
Reference
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