Name: Rachel
Status: Student
Grade: 9-12
Location: IL
Country: United States
Date: November 2008
Question:
How does an antibiotic-producing Streptomyces sp. prevent
killing itself by its own antibiotics?
Replies:
Many micro-organisms rely on 'chemical warfare' to protect themselves
from other species. Each organism produces chemicals which are harmless
to itself, but hopefully are toxic to other species which may want to
occupy the same space. The result is that no antibiotic will affect ALL
bacteria, nor will any bacteria be affected by all antibiotics.
This applies to the Stretomyces as well as any other species.
It is because of this specificity of antibiotic action that it is necessary
for doctors to test a range of antibiotics before beginning a course of
treatment. It is also a large part of why bacteria make you sick in the
first place - as well as affecting other bacteria, the chemicals produced
by the bacteria may affect living cells in the host body. Hence it is possible
for a bacterial infection in the throat to cause nausea and headaches as you
swallow the toxic products.
Nigel Skelton
Tennant creek High School
AUSTRALIA
Every antibiotic has a specific way of killing bacteria. For example, the
antibiotic might attack a specific protein that some bacteria needs to live.
Often, the antibiotic producer doesn't need (or doesn't have) the protein
that the antibiotic attacks... which is how it can remain unaffected while
other bacteria around it are killed.
Hope this helps,
Burr
Streptomycin binds to the ribosomes of susceptible bacteria and inhibits
protein synthesis. The ribosomes of Streptomyces bacteria do not bind streptomycin
so Streptomyces is not affected by the antibiotic. Bacteria that are killed by
streptomycin can undergo mutation and become resistant to the drug because their
ribosomes have a different shape and no longer bind streptomycin.
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