Bacteria: FRIEND OR FOE
Bacteria: Friend or Foe?
Bacteria are all around us and most people only consider these prokaryotic organisms to be disease causing parasites. While it is true that bacteria are responsible for a large number of human diseases, they also make it possible for certain elements such as carbon, nitrogen, and oxygen to be returned to the atmosphere.
Life as we know it would not exist without bacteria to decompose waste
and dead organisms. These bacteria ensure that the cycle of chemical
exchange between organisms and their environment is continuous.
The decision as to whether bacteria are friend or foe becomes more
difficult when both the positive and negative aspects of the
relationship between humans and bacteria are considered. Let's discuss
three types of symbiotic relationships: commensalism, mutualism, and
parasitism.
Commensalism is a relationship that is beneficial to the bacteria which
live off of the host, but does not help or harm the host. Most of the
bacteria that reside within the bodies of humans are commensalistic.
In a mutualistic relationship, both the bacteria and the host benefit. For example, there are several types of bacteria
which live inside the mouth, nose, throat, and intestines of humans and
animals. These bacteria receive a place to live and feed while keeping
other harmful microbes from taking up residence.
A parasitic relationship is one in which the bacteria benefit while the
host is harmed. Pathogenic parasites, which cause disease, do so by
resisting the host's defenses and growing at the expense of the host.
These bacteria produce poisonous substances called endotoxins and exotoxins which are responsible for the symptoms that occur with an illness.
When all of the facts are considered, bacteria are more helpful than
harmful. Humans have exploited bacteria for a wide variety of uses, such
as: making cheese and butter, decomposing waste in sewage plants, and
developing antibiotics. Bacteria have been able to survive without us,
but we could never live without them.
