INTRODUCTION
Because
of their extreme minuteness, bacteria are not generally studied with the
low-power or high power-power dry objectives. Instead they are stained and
observed with the oil immersion objective.
The wet
mount method enables you to study the sizes and shapes of living microorganisms
(drying or staining microorganisms distort them). It also enables you to
determine if cell are motile. The wet mount method is quick and easy, and does
not require special equipment.
OBJECTIVE
· To provide an experience in the use of microscope.
· To illustrate the diversity of cells and microorganisms.
RESULT
1. Typical bacillus
40x magnification
100x magnification
400x magnification
2. Lactobacillus fermentum
400x magnification
1000x magnification
3. Sacchamnyces arerisiae
400x magnification
1000x magnification
DISCUSSIONS
1. Stained cells
From the
observation of Typical bacillus we can classify it as the Gram positive
bacteria. It has thick wall made of peptidoglycan and has rod-shaped. It can
traps crystal violet in the cytoplasm and gives purple-black colour. The
alcohol rinse does not remove the crystal violet, which mask red safranin dye
is added.
Bacteria cell walls that contain
peptidoglycan, is a network of modified-sugar polymers cross-linked by short
polypeptides. It used different magnification to observe the bacteria under
microscope and to get the clear views, which are 40x, 100x, and 400x
magnification.
2. Wet mount
For these experiment, the wet mount methods
which helps us to study about the shapes and the sizes of living organism. In
this method, the drop of liquid of the specimen that is located between slide
and cover glass is suspended. When using wet mount method, it is more fasters
to prepared and it is possible to observe the living and moving organism. We
observed the organism with different magnification that is 4x, 10x, and we also
used immersion oil. The function of using the immersion oil is to get final
resolution and brightness. We can get more clears image. In higher
magnification, these characteristics are most critical.
We also used aseptic technique in this method.
Inoculating wire is slowly heated until its glows orange. Cool it before
attempting any bacteria. Then, we also heat the mouth of opening bottle. This
is to make sure that we are not infected and to prevent the spread of
microorganisms.
During
this experiment, the Lactobacillus fermentum is observed under 40x, 100x magnification.
We can see the rod-shaped structure and also the moving of organism.
Lactobacillus cannot be seen under 4x and 10 magnification because it’s not
tiny. It also same goes to yeast, we are unable to see the organism under 40x,
100x magnification. Yeast are the fungi which do not contain chlorophyl under
the microscope. We can see it is cocci or spherical shape. We also can see
clears images of shape when use oil immersion at 100x .
CONCLUSIONS
CONCLUSIONS
There are two type of gram. Gram positive and
gram negative. Gram positive and gram negative bacteria have similar internal but
very different external structures. Gram positive bacterium has a thick, multi
functions cell wall consisting mainly o f peptidoglycan surrounding the
cytoplasmic membrane. Staining reaction take advantages of the facts that the
cells or structure within the cell display dissimilar staining reactions that
can be distinguish by the used of different type of dyes. Gram technique is
used to differentiate two large groups of bacteria based on their different
wall constituents. Gram positive bacteria stain violet due to the presence of
the thick layer of peptidoglycan in their cell walls, which retains the crystal
violet their cells are stained with.
The immersion
oil is used to take advantage of the highest resolving powers available to the
microscopist. Unless this is a necessary requirement of the work in hand, stay
with the lower power dry objectives. They are much less trouble to use and can
provide magnification up to 600x (using a 40x, 0.65NA dry objective with 15x
eyepiece) at quite acceptable resolution. Lactobacillus also has been
identified as potential of probiotic.
Some samples can be placed directly under the
microscope. However, many samples look better when placed in a drop of water on
the microscope slide. This is known as “we mount”. The water helps to support
the sample and it fills the space between the cover slip and the slides
allowing light to pass easily through the slide of the sample, and cover slip.
REFERENCES
v Pearson
International Biology, 8th Edition, Campbell,Reece
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