Are Human Beings Organisms Or Living Ecosystems? 397
Hugh Pickens writes "Every human body harbors about 100 trillion bacterial cells, outnumbering human cells 10 to one. There's been a growing consensus among scientists that bacteria are not simply random squatters, but organized communities that evolve with us and are passed down from generation to generation. 'Human beings are not really individuals; they're communities of organisms,' says microbiologist Margaret McFall-Ngai. 'This could be the basis of a whole new way of looking at disease.' Recently, for example, evidence has surfaced that obesity may well include a microbial component. Jeffrey Gordon's lab at the Washington University School of Medicine in St. Louis published findings that lean and obese twins — whether identical or fraternal — harbor strikingly different bacterial communities that are not just helping to process food directly; they actually influence whether that energy is ultimately stored as fat in the body. Last year, the National Institutes of Health launched the Human Microbiome Project to characterize the role of microbes in the human body, a formal recognition of bacteria's far-reaching influence, including their contributions to human health and certain illnesses. William Karasov, a physiologist and ecologist at University of Wisconsin-Madison, believes that the consequences of this new approach will be profound. 'We've all been trained to think of ourselves as human,' says Karasov, adding that bacteria have usually been considered only as the source of infections, or as something benign living in the body. Now, Karasov says, it appears 'we are so interconnected with our microbes that anything studied before could have a microbial component that we hadn't thought about.'"
Good Germs Bad Germs (Score:5, Informative)
I just read Good Germs Bad Germs by Jessica Snyder Sachs, a fascinating, accessible and up-to-date account of roughly the same subject matter. Will change your view on bacteria forever.
http://www.amazon.com/Good-Germs-Bad-Survival-Bacterial/dp/0809050633 [amazon.com]
Sounds like "LIves of a Cell" by Lewis Thomas 1978 (Score:5, Informative)
radiation (Score:3, Informative)
Makes sense. I read somewhere that one of the reasons medium/high doses of radiation kill you is all the helpful bacteria in your digestive system are killed, leaving you unable to process nutrients.
Re:Star Trek... (Score:3, Informative)
No, it was a Futurama episode in season 3
http://en.wikipedia.org/wiki/Parasites_Lost [wikipedia.org]
Re:Obesity & Bacteria (Score:5, Informative)
It's how much energy you consume vs how much you use which decide if you get fatter, stay the same or thinner.
Not the quality of the food.
10000 kcals of spinach and you will most likely get more fat.
500 kcals from chocolate and you'd lose weight.
Not exactly. It's not how much energy you consume, but how much energy you gain out of it. Given the right ecosystem in your bowels, you might be able to process 100% of that choccolate-energy, but only 10% of that spinach-energy.
Entertaining related TED talk (Score:3, Informative)
Humans (just) human idea also referred to by Bonnie Bassler in excellent talk here:
http://www.ted.com/index.php/talks/bonnie_bassler_on_how_bacteria_communicate.html [ted.com]
Re:Obesity & Bacteria (Score:5, Informative)
why is it worded in such a way as to imply the different bacteria is the reason that one is obese and the other isn't, instead of the type of bacteria changed because being obese
IIRC there have been animal studies (mice I think) where changing the intestinal bacteria lead to changes in obesity. I don't have an article cite, but I read about it in Science News about a year ago. So it's not simply a correlation that supports this theory.
Re:Obesity & Bacteria (Score:4, Informative)
This would explain what was previously thought to be genetic obesity. I'm obese, as are most of my mothers family. My father is skinny and eats terrible food.
I eat very healthy and I exercise about 20-30 minutes a day(bike riding or swimming) and yet I still weigh 172 @ 17% body fat. Obviously for some people eating healthy and exercising isn't enough.
Whether its genetics or microbes, I don't really care. It does bother me though that people in general blame obese people for their weight. Maybe in a lot of cases that negative view is warranted, but probably for a lot of other cases like me, it isn't laziness.
Re:Obesity & Bacteria (Score:4, Informative)
It's how much energy you consume vs how much you use which decide if you get fatter, stay the same or thinner.
That is plain wrong. It is how much energy of the amount you consume is processed that decides whether you're obese.
And I can prove it: When under stress from work, I tend to eat very little. I usually gain weight during that period of time. In contrast, whenever I have a vacation of more than one week where I am indeed relaxing while stuffing my face with food (e.g. Christmas), I usually tend to lose weight.
This phenomenon is not unique either. Studies have been conducted (at reputable universities like Harvard, mind) that came to the conclusion that the amount and type of food is not directly linked to obesity.
Again, for those who understand German I'd recommend "Esst doch endlich normal" by Udo Pollmer.
He has collected many references (with sources mentioned) to studies that show more correlation between levels of cortisol and obesity than fat or sugar.
Since I have made observations that agree with this theory, I tend to agree with it as well.
Also, I don't quite understand your comment about omnivores. Are you saying we are or we are not omnivores?
Re:Obesity & Bacteria (Score:5, Informative)
Do antibiotics wipe out everything in person's gut, or is there enough left over that people get recolonized with the same set of microbes they had before taking the antibiotics? Also, are the bacteria that might influence weight gain susceptible to common antibiotics that wipe out most other bacteria in the gut? The summary had a link [npr.org] to an article on the fat bacteria, and it contained the following.
"The issue, then was to determine which came first: the fat, or the bacteria. To find out, the lab took mice that had never been exposed to any bacteria, whose guts were totally germ-free. Half of them got bacteria taken from skinny mice. The other half got bacteria from fat mice."
"Both groups put on body fat. But the mice that received bacteria from obese donors gained more fat over the course of the experiment."
Re:Obesity & Bacteria (Score:3, Informative)
I don't recall where I read it, but I distinctly remember reading something along the lines that the appendix serves as a resevoir of gut bacteria, and that it replenishes normal gut bacteria after episodes of horrific diarrhea, for example.
I don't know if the appendix is sufficiently protected from antibiotic dispersion in the gut to be effective after a course of antibiotics. I do know that, for me, taking probiotic supplements after a course of antibiotics helps me return to regular. I'm on antibiotics frequently due to Lyme Disease.
One more note -- I'm not skinny. At all. Though I'm fairly fit (can run 3 miles in 21 minutes).
Re:radiation (Score:3, Informative)
I read somewhere that one of the reasons medium/high doses of radiation kill you is all the helpful bacteria in your digestive system are killed, leaving you unable to process nutrients.
Well, that and the internal burns, shredded DNA, denatured proteins, and general nastiness that results from your insides being subjected to bursts of concentrated energy.
Re:Viruses, too (Score:3, Informative)
They've also discovered that viruses in the wild actually quite easily jump from species to species, too.
Some do. Rabies appears to infect most mammals, but that's an incredible range for a virus, and there is one virus that can at least tolerate being in a host from a completely different kingdom, don't remember the name of it but it can live in aphids and some plant species (also not sure which one it prefers). As I understand it, most viruses seem to stay within their host species though, it's typically a very lucrative niche. I'd guess it depends on the specific virus, some because of their mechanisms are probably more able to jump to certain species than others.
Comment removed (Score:3, Informative)
Re: Point of view (Score:2, Informative)
Bacteria are prokaryotic. Human cells are eukaryotic. So we're a colony of mostly prokaryotes, if we're just counting cells. The eukaryotic human cells win the total mass race, however.
Ah, Microbes! (Score:2, Informative)
There seems to be at least one scientist that believes so. Dr. Jaroslav Flegr from Prague Charles University (founded in 1348 is one of the oldest universities in the world and nowadays is one of the most eminent educational and scientific establishments in the Czech Republic) published some mind-blowing discoveries.
Dr. Flegr's claim is a simple one. Microbes influence YOUR decision-making.
You will find the presentation here http://www.natur.cuni.cz/~flegr/toxo_slides/index.php [natur.cuni.cz]
If you dare to reach slide 14 you will learn that:
"The infected women had higher affectothymia, which means, they were more warm-hearted, outgoing, easygoing. They had also higher superego strength, which means, they were more conscientious, persistent, moralistic, staid. Both men and women had higher guilt proneness."
Now, why this is not a mainstream science I do not know. But I will leave it for you to decide.
You can research that or you can go to flickr.com and type "Empire Builder" in the search box and see some really cool photos.
The choice is yours...
(or is it?)