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Exploring Microorganisms Around You
By Marianelly Lopez, Edima Akpan, and Kelechi Okereke
Microbiology is simply the study of microorganisms that are in every place
imaginable. The importance of understanding microbial diversity and obtaining
information is to find the origins of how viruses and diseases develop. Microbial
diversity must be understood in order to use the knowledge of microorganisms to find
cures for diseases and viruses. In order to be a microbiologist, one must be curious about
small microscopic life, study microorganisms from various environments, and be
rigorous in the study of microbiology.
The domains of the old tree of life used to be Prokaryotes and the Eukaryotes.
But in today’s society of science, the new domains are Archaea, Bacteria, and Eukarya.
Archaea and Bacteria are no longer grouped in the same category under Prokaryotes
because their structures are different from one another. Bacteria have peptidoglycen in
its cell membrane made up of phospholipids while Archaea has a polysecondary
membrane. In addition, Eukarya contains a nucleus whereas Archaea and Bacteria do
not. Today’s three domains of life are based upon the 16S ribosomal unit to classify
microorganisms because it is the most conserved subunit. The small subunit is used
because of the nucleotide differences in the ribosomal unit to identify groups of species.
Some of the techniques that we used in this scientific experiment are Fluorescence
in Situ Hybridization and inoculation. Procedures that we used were culturing and
isolating.
The objective of this experience was to study the microorganisms in the
environment and examine how diverse they were. The purpose of this experiment is to be
able to grow microorganisms in an enclosed area and to be able to identify the
microorganisms’ classification.
The first part of our experiment was to collect microorganisms from various
places. Samples were taken from the Memorial Pond, the underside of a shoe, and the last
from the refrigerator. The microorganisms had to be placed on agarose gels containing
media with nutrients, and were incubated for about two days.
After the incubation, we saw the results from under a dissection microscope.
Edima’s sample contained homogeneous colonies, each being pinkish and smooth.
Marianelly’s sample seemed to contain various different colonies. Some were veinshaped and white; others were more pinkish or yellowish. Kelechi’s sample had two
distinct colonies. One colony was small, thin, clear, and tightly packed together, while the
other colony was white and separated from each other.
That was only the first part of the whole experiment. The next step was to collect
a specific colony from the previous experiment. Using the techniques inoculation,
incubation, and striking, we grew our chosen colonies on agarose gel containing media
(food) with nutrients for one day.
All of our results were different. Kelechi’s Petri dish was covered with the chosen
organism. They were exactly the same ones that he had collected before. His colony
contained white splotches, had ridges and smooth sides, and were more whitish than the
agarose gel. Edima’s Petri dish had one colony following the streak that she had made
earlier. This colony was pinker than the original colony, and contained smooth pinched
colonies. All of her colonies were tiny circles. Marianelly’s Petri dish seemed to have
grown two different colonies in the agarose gel. One of the colonies were a pale pink
color and were separated from each other as well as the other existing colony, while the
other colony was a dull white and were tightly formed together and following the
streaked line.
The final part of the experiment was to identify which colonies were bacteria,
Archaea, or eukaryotes through a technique classified as Fluorescent In Situ
Hybridization (FISH). This powerful technique evaluates and analyzes the presence of
organisms in a community, their phylogeny, morphology, and number by targeting the
16S rRNA. To differentiate the organisms, fluorescent probes were added to the samples.
If the sample has red organisms, it is universal bacteria. If it has blue organisms, it will
either be Archaea or Actinobacteria. If the sample turns green, it will either be universal
eukaryote or Gama proteobacteria.
Results from this portion of the experiment were interesting. All samples
contained universal bacteria as observed using the fluorescent microscope, given by the
red color. Kelechi’s sample contained specifically Gama proteobacteria given by the
green color, while Edima and Marianelly’s samples contained Archaea and
Actinobacteria, with the assigned color blue.
To sum things up, we saw how diverse our samples were. Some of the samples
were similar, while others were different. We accomplished our goals for the project. We
explored microbial diversity, were able to grow microorganisms in a lab, and were able to
identify the microorganisms’ location on the tree of life. Overall, the experiments were
successful.
Each of us SMASH scholars enjoyed our experience. We all enjoyed doing the
project and it has made us more interested in pursuing careers in science. We have
learned how many diverse microorganisms are around us and how there is a newer
version of the tree of life. As Marianelly said, a member of the team, “…everything that
we did was exactly what I had imagined what we would do and more.” This project has
really helped us to experience what it was like to be working in a real lab. We were able
to learn a lot in terms of microbiology. The project has overall been an enjoyable
experience and we all had a really great time conducting this project. We can only hope
that we could do it again.
REFERENCES:
1. Madigan, M.T., Martinko, J., Parker, J., Brock Biology of Microorganisms. 12th ed.
2003, Upper Saddle River, NJ: Prentice Hall.
2. "Main Page." Wikisource, The Free Library. 20 Jun 2009, 06:18 UTC. 4 Jul 2009,
05:10 <http://wikisource.org/w/index.php?title=Main_Page&oldid=257433>.
3. <http://microbewiki.kenyon.edu/index.php/MicrobeWiki>.
4. Philip Hugenholtz, Gene W. Tyson, and Linda L. Blackall. Design and Evaluation of
16S rRNA-Targeted Oligonucleotide Probes for Fluorescence in Situ
Hybridization. Methods in Molecular Biology, vol. 176: Steroid Receptor
Methods: Protocols and Assays. Chapter: 6-Hugenholtz.