For the rest of my ISP, I am planning on synthesizing the information I have gathered on bacteria in an essay no more than 4000 words, possibly in the form of a thesis. Here is a short snippet from my essay so far:
The diversity of bacteria is sustained by their short generation span.
Constantly adapting to changing environments, they have the ability
to have an omnipresent impact on human life, as well as on the lives of other
animals.
The intestinal bacterium E. coli is the epitome of such
diversity. Through extensive studies, E. coli has presented
most of the information we now know about bacteria. The double-stranded,
circular DNA molecule is important to the bacterial genome: it is tightly
packed in a region called the nucleoid and does not contain a binding membrane.
Another characteristic that sets bacteria apart from eukaryotic
organisms is that they contain several plasmids that are not necessary for
survival, but may be beneficial in harsh environments—another factor that adds
to the malleability of these microbes.
Bacteria, including E. coli, are also extremely successful
because of their ability to proliferate so rapidly through asexual
reproduction. It has been calculated that approximately nine million E.
coli genes are mutated through this process per day per human host. This
data supports the conclusion that bacteria can adapt to an environment through genetic
mutation; those that survive will go on to reproduce. Though mutations are a
major source of variation within a bacterial population, a process called genetic
recombination can add more diversity to a population.
One study involving E. coli proves this. Wild-type E. coli (non-mutant) can survive only on a medium of
glucose. However, two mutant strains, one of which cannot produce tryptophan,
and the other that cannot synthesize arganine. When both the strains were mixed
together and incubated on a minimal medium, growth occurs, showing that genetic
recombination has occurred, making the two individual strains successful in an
environment containing a minimal nutrition source.
In addition to being so versatile independently, bacteria can be used by
scientists to exemplify certain genes present in non-bacterial organisms. A
certain gene of interest (from any cell, including eukaryotic ones) can be
isolated and inserted into a plasmid from a bacterial cell. The plasmid containing
the gene of interest can be placed back into the bacterial cell, which is then
cloned. When the bacteria reproduce, only some express the gene of interest.
This strain of the bacteria can then be used for a variety of things, such as
pest resistance for plants, or the treatment of stunted growth in animals.
Another piece of evidence showing that bacteria are extremely successful
on earth is that bacteria were some of the first organisms to appear on the
planet, about three thousand five hundred million years ago. The fact that
these seemingly simple organisms have kept their genus intact for 3500 million
years is undeniable proof of their complexity. As proof of their diversity,
about five thousand species are currently known. These species may differ in their
shape (coccus, bacillus, helical), motility (flagella, spirochetes), function,
and nutritional or metabolic diversity.
Though popular culture has lead us
to associate the term bacteria with harm, many bacteria are actually quite
useful. E. coli, a previously mentioned example, is useful in research,
but is also found in the human intestine... (Note: I am not completely done
with this paragraph yet…)
These deceptively simple creatures
have immensely complex ways of communication as well. Bacteria secrete autoinducers
(chemical signal molecules) in order to communicate. These molecules can
regulate gene expression and behavior by detecting the concentration of a
certain autoinducer. This method of communication can allow bacteria to act
like multicellular organisms. For example, on study conducted by Bonnie
Basselor and her peers…(Note: I am not completely done with this paragraph yet…)
At this point, my study of bacteria
appeared somewhat broad, so I attempted to narrow my focus from the diversity
of bacteria to developing methods of preventing harmful bacteria from entering
human systems. Previously, an antimicrobial by the name of Triclosan, or Microban
was used. Triclosan proved to be effective, but there were soon rising concerns
about the toxicity of triclosan because it is a possible carcinogen, and is
closely related to dioxin. Over the years, the use of this antimicrobial declined.
However, this brief study of
antimicrobials introduced me to another of the wonders of bacteria: triclosan
also brought up concerns because bacteria easily gained antibiotic resistance
to it. The concern that they adapted so easily, in just a few generations,
amazed me and uncovered a whole new layer of versatility in the world of
bacteria.
Please note that the above fragment is only a small part of my entire essay. The full essay is much more detailed, but I do not want to release the entire paper all at once.
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