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.'"
Obesity & Bacteria (Score:5, Interesting)
So the bacteria in the twins is different... 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 (and the eating that goes along with it) favor one type over the other.
Microbiologists... (Score:1, Interesting)
Let me remind everyone that microbiologists are almost a different species (if we were organisms). I suppose, in this case, they could also be likened to a different planet.
Yogurt (Score:3, Interesting)
Re:Obesity & Bacteria (Score:5, Interesting)
I've been struggling with obesity for some time now. I eat more healthy than many of my slimmer friends and I often work out more, yet I still weigh considerably more.
Does this mean that it's impossible for me to loose weight? No way, I have been exercising more and eating better and I know have been shedding more pounds. It's just frustrating to watch them eat more junk and not work out at all, and remain slim, where as I would balloon :|
Re:Obesity & Bacteria (Score:3, Interesting)
Absolutely! I for one reject this studies' thinly veiled attack on the hegemony of genetic determinism!
Viruses, too (Score:5, Interesting)
A recent program on NatGeo (Explorer?) hypothesizes that viruses are also a key part of human evolution.
The "junk DNA" that we all have is likely the result of viruses.
They've also discovered that viruses in the wild actually quite easily jump from species to species, too.
In one of the experiments, they found a large amount of a certain virus in the womb of a sheep during pregnancy. When inoculated against the virus, the pregnancy would not complete.
Very interesting theory.
Re:Obesity & Bacteria (Score:1, Interesting)
Does this even pass the sniff test? I take antibiotics. I wipe out an entire ecosystem. I become obese or skinny randomly depending upon which new ecosystem appears.
My personal experience does not reflect that. I do not know of anyone else who has had shifts in weight after antibiotics, either.
I am thinking that it is more likely that the diet we have is causing us to be obese or skinny. The symbiotic bacteria that appears is probably also resulting from the diet we have.
The axiom "correlation is not causation" still holds, and I may be wrong. The rest is an excercise to the reader.
Re:Obesity & Bacteria (Score:5, Interesting)
I don't know what your point was, but this wouldn't refute genetic determinism; it just says that the genes determining "you" include those of bacteria.
Incidentally, I don't understand what's so new about this insight. I read a book published in 1995, Darwin's Dangerous Idea by Daniel Dennett (a philosopher rather than a biologist so he was only drawing on what was long-established consensus at the time). It described the view of the body as an ecosystem and suggested that human cells were like "altruistic versions of ant cells" since human cells share even more genetic material (100%) with their neighbors.
100 trillion mitochrondia too (Score:4, Interesting)
DNA shot gun analysis is a powerful analysis tool (Score:4, Interesting)
Shotgun DNA is a "similar, but different approach". They first map every piece of DNA in every microbe (but in pieces). Then they look for a few key sequences somewhat conserved among species, and note minor differences. This distribution of differences gives a count of species and relatives amounts of each. Later on they may connect these to actual microbe types.
Re:Obesity & Bacteria (Score:4, Interesting)
Let me give you an example. Right after most people eat their heart rate and metabolic response drops, often they feel a bit less energetic and alert, and their body switches "modes" in how it burns energy, usually burning less and storing more at this point. However my body is different. When I eat my heart rate and metabolic response increases by anywhere from 20 beats per minute to 60 bpm. I get warmer, become more alert and more energized.
During that period immediately following eating I can usually exercise longer than other times and not feel tired at all. But ironically this doesn't mean that I am skinny. In fact I am obese. My body stores energy from everything and is VERY efficient at squeezing every last bit of energy and nutrition out of food. My best friend by contrast is skinny and would collapse if he at the same amount of calories that I do (I currently average between 1500 - 2000 calories a day). He has to eat at least twice as much as I do just to function. His digestive system is highly inefficient and his heart rate and metabolic response drops off after eating.
Now another thing that research has shown is that if you spread out your calories across 5 meals in a day you will burn more calories and store less than when eating the same number of calories in 3 or less meals in a day. This technique is used by many to help them lose weight to great effect.
So giving some blanket statements about getting fat or thin just don't apply. It really varies from person to person as to what things effect what people.
Re:Obesity & Bacteria (Score:3, Interesting)
Random thought - I was just reading about the efficacy of phage therapy for wounds that were not responding to antibiotics.
Re:Body is the Vessel for the Soul (Score:2, Interesting)
Lemon juice is alkalizing in the body, depite that the juice itself is acidic.
Re:Obesity & Bacteria (Score:1, Interesting)
I was never even close to fat until my appendix came out.
Re:Viruses, too (Score:2, Interesting)
From what I recall of the program, a series of blood tests were performed on a range of dead animals found in the jungle (somewhere in Africa).
A comparative study was performed with blood samples from the local tribes people. It's there they discovered a multitude of viruses that would otherwise have been assumed animal specific.
Here is a link which I believe is the episode: Explorer [nationalgeographic.com]
The concept is rather frightening, if you think about it.
Re:Obesity & Bacteria (Score:1, Interesting)
Isn't this close to what Scientologists believe?....scary
Not so much living IN humans as living ON them (Score:3, Interesting)
I kind of object to the notion that these bacteria are living inside us as if they are parts of our bodies. As I understand it, the great majority are in our guts; most of the remainder are in skin and mucous membranes that are somewhat exposed to the outside.
The gut is not exactly part of the body. Topologically it has often been noted that the human body is like a tube or torus (a doughnut shape). Yes, there are several sphincters and other openings that can close off the gut, starting with the mouth and ending with the anus. But they open sometimes and they do offer passageway between the outside world and the inside. The gut is more like the skin in terms of how the body distinguishes the external world from its internal environment. It patrols its internals rather vigorously and attempts to destroy bacteria. "Outside" bacteria are tolerated, there is no immune system active outside the body.
So there is still a very significant distinction between those cells which are part of our body, and those cells, including these vast numbers of bacteria, that are outside our body. The gut doesn't really count.
Re:Obesity & Bacteria (Score:2, Interesting)
Oh, I don't know. I've observed bacteria directly through a microscope. Granted, it has only been around for hundreds of years, but I don't consider it a "mystical tool".
Additionally, I have seen the effects of bacteria, as witnessed through a microscope that would reasonably allow me to come to the conclusion, without claiming "magic", that they do influence the hosts and environments in which they live.
Demons, on the other hand, I can't witness since I can't go to Hell and observe them in their supposedly natural environment. I can't witness them corrupting the youth or taking the form of serpents and offering apples to young women not wearing much.
I see your point, that some things ascribed to demons from ancient times were really bacteria. However, I don't see the point of observing that. We know that already, which is why we don't ascribe demons to anything outside of religious or mythical realms anymore.