More evidence we are bacteria-sapiens

From Robert Martone, in Scientific American, “The Neuroscience of the gut”:

We human beings may think of ourselves as a highly evolved species of conscious individuals, but we are all far less human than most of us appreciate. Scientists have long recognized that the bacterial cells inhabiting our skin and gut outnumber human cells by ten-to-one.

Indeed, Princeton University scientist Bonnie Bassler compared the approximately 30,000 human genes found in the average human to the more than 3 million bacterial genes inhabiting us, concluding that we are at most one percent human. We are only beginning to understand the sort of impact our bacterial passengers have on our daily lives.

Moreover, these bacteria have been implicated in the development of neurological and behavioral disorders. For example, gut bacteria may have an influence on the body’s use of vitamin B6, which in turn has profound effects on the health of nerve and muscle cells. They modulate immune tolerance and, because of this, they may have an influence on autoimmune diseases, such as multiple sclerosis. They have been shown to influence anxiety-related behavior, although there is controversyregarding whether gut bacteria exacerbate or ameliorate stress related anxiety responses. In autism and other pervasive developmental disorders, there are reports that the specific bacterial species present in the gut are altered and thatgastrointestinal problems exacerbate behavioral symptoms. A newly developed biochemical test for autism is based, in part, upon the end products of bacterialmetabolism.

But this new study is the first to extensively evaluate the influence of gut bacteria on the biochemistry and development of the brain. The scientists raised mice lacking normal gut microflora, then compared their behavior, brain chemistry and brain development to mice having normal gut bacteria. The microbe-free animals were more active and, in specific behavioral tests, were less anxious than microbe-colonized mice. In one test of anxiety, animals were given the choice of staying in the relative safety of a dark box, or of venturing into a lighted box. Bacteria-free animals spent significantly more time in the light box than their bacterially colonized littermates. Similarly, in another test of anxiety, animals were given the choice of venturing out on an elevated and unprotected bar to explore their environment, or remain in the relative safety of a similar bar protected by enclosing walls. Once again, the microbe-free animals proved themselves bolder than their colonized kin….”

Read it all on Scientific American.


Filed under News

3 responses to “More evidence we are bacteria-sapiens

  1. Tony

    This is not really news we have know for a decade or more that bacteria, plants, animals and humans have similar genes e.g. 50% are basically the same thats why adding a bacterial gene for glucose isomerase or some other enzyme to a plant that already has similar genes coding for similar proteins is not such a big deal. Kill of our bacteria in us and we would get sick – we need them for good health

  2. Pingback: Gut Bacteria Influence Brain and Behavior - Details Matter | CorePsych Blog

  3. aaron

    The thing is, we ARE the germs. we’re bacteria thriving on the one habitable celluloid.. depleting resources and procreating to the point of infestation. NASA is nothing but a virus trying to latch on to another host.. we’re like the equivalent of fleas on a dog, or the flu virus passing between one organism to another. the earth itself is alive, along with all the other planets, which build up to make a living solar system, which with our star and many others build up to make the living galaxy and so on and so forth.. thus, the final biomolecular organism at the peak of the building blocks is, what some people might refer to, god. the doctors keep us alive long enough to feed and plunder and go about our germly duties. so think about that the next time you go to work, or to a fast food resteraunt.. or look at a city through google maps. It’s plain as day. so, in conclusion, you are but a cell, building up with an uncountable amount of other organisms to make the great life that is the universe. I hope I enlightened you and have a nice germy day. 🙂

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