Download Spring 2015-Chapter 6

yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Microbiome A microbiome is "the ecological community of commensal, symbiotic, and
pathogenic microorganisms that literally share our body space."[1][2] Joshua Lederberg coined the
term, arguing the importance of microorganisms inhabiting the human body in health and
disease. Many scientific articles distinguish "microbiome" and "microbiota" to describe either
the collective genomes of the microorganisms that reside in an environmental niche or the
microorganisms themselves, respectively. The human body contains over 10 times more
microbial cells than human cells, although the entire microbiome only weighs about 200 grams
(7.1 oz),[6][7] with some weight estimates ranging as high as 3 pounds (approximately 48 ounces
or 1,400 grams). Some[who?] regard it as a "newly discovered organ" since its existence was not
generally recognized until the late 1990s and it is understood[by whom?] to have potentially
overwhelming impact on human health.[8] Modern techniques for sequencing DNA have enabled
researchers to find the majority of these microbes, since the majority of them cannot be cultured
in a lab using current techniques. The human microbiome may have a role in auto-immune
diseases like diabetes, rheumatoid arthritis, muscular dystrophy, multiple sclerosis,
fibromyalgia, and perhaps some cancers. A poor mix of microbes in the gut may also
aggravate common obesity. Since some of the microbes in our body can modify the production
of neurotransmitters known to be found in the brain, we may also find some relief for
schizophrenia, depression, bipolar disorder and other neuro-chemical imbalances.
Researchers have started to characterize microbiomes in many non-human environments as well,
including soil, seawater and freshwater systems. It is believed[by whom?] that endosymbiosis
originally gave rise to more complex organisms, and continued to play a fundamental role in
guiding their evolution and expansion into new niches.[citation needed]
The microbes being discussed are generally non-pathogenic (they do not cause disease unless
they grow abnormally); they exist in harmony and symbiotically with their hosts.[9]