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Every Man Is an Island (of Bacteria)
Shipud writes "There are ten times more bacterial cells in our body than our own cells. Most of them are located in our guts, and they affect our well-being in many ways. A group at Washington University has recently reported that although our gut microbes perform similar functions, it appears that different people have completely different compositions of gut bacteria: every man is an island, a unique microbial ecosystem composed of completely different species. One conclusion is that the whole division of bacteria into species may well be over-used in biomedicine."
Each of your cells takes up 100-1000x more space than bacteria.
Prokayrotic (most bacteria) cells are much much smaller than Eukaryotic (your body) cells. Therefore event though you have less cells, those cells you do have weigh much more.
Bacteria are a tiny fraction of the size of your cells.
http://www.cellsalive.com/howbig.htm has a nifty little flash movie demonstrating the size difference.
If I have been able to see further than others, it is because I bought a pair of binoculars.
Bacteria do not digest your teeth. They eat the sugar that you consume. It's their #2 (as you called shit) that dissolves the enamel on your teeth.
Sure, it's possible: We know that Crohn's / Ulcerative Colitis have genetic predisposition - it's certainly possible that a susceptible person's immune system sees a particular bacterium or portion thereof or byproduct thereof and starts down the pathway of an autoimmune phenomenon.
from Feldman: Sleisenger & Fordtran's Gastrointestinal and Liver Disease, 8th ed.
So sure, maybe. Stay tuned.
Faster! Faster! Faster would be better!
Yes, and changing the population of gut bacteria in mice can control whether the mice stay thin or get fat.
Briefly, mice with no gut bacteria were innoculated with bacteria from either obese or lean mice. The animals given bacteria from obese mice got fat, the animals given bacteria from lean mice stayed thin. There's a good writeup here.
The details for humans aren't known, but it seems likely that it's basically the same for us. I used to know a guy who worked on classifying gut bacteria. He was always desperate for samples so almost all of his friends had, at some stage,kept a food diary then provided him with a turd in a box to work on. It's important work, but we were all secretly afraid that our samples were actually going into the construction of some sort of shrine...
Also: farts are gas released by your gut bacteria, not directly from you. So if you have a particularly deadly brand it's not your fault, it's your bacteria.
Um, most of your body weight is water. And water is not cells :)
Actually, the vast majority of the water in your body is found inside your cells, so in fact water IS cells (or rather cells ARE water)
Basically, species classifications are ambiguous and fuzzy even in higher animals, but they've served us really well as modelling tools, much like Newtonian physics, so we apply them everywhere. As long as we keep it in mind that they're not necessarily accurate, it's a fine idea.
With that said, there are characteristics that are unique to some species of bacteria, and shared by all members of that species. It's not a terrible approximation. All Clostridium species are anaerobic, for instance. So if you have a huge population of bacteria, and you divvy them all up according to a whole raft of tests -- aerobic/anaerobic, gram+/gram-, pili/no pili, sporulating/nonsporulating and so forth -- at the end you have a whole bunch of groups, and within each group you find an extremely high similarity in DNA sequence, much more similar than a member from a different group. It's not a terrible idea to call that a species, even if it might not mean exactly the same thing that we mean when we apply the term to animals.
Nostalgia's not what it used to be.
"Common knowledge you can find in most microbiology or immunology textbooks" doesn't generally get a publication in Nature.
I've worked with one of the authors (Rob Knight) of the most recent paper, so I have some idea of what their research entails. Basically they were expecting to find some diversity in bacterial populations between individuals, but the amount they found was the big surprise -- there is more genetic diversity between the gut bacteria population of any two randomly selected people than there is between two soil bacteria populations in a deep sea trench and on a mountaintop! How strongly the bacterial populations predict leanness vs. obesity was also far beyond any previously published result.
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
Something doesn't make sense:
There are ten times more bacterial cells in our body than our own cells. Most of them are located in our guts
That means that over 50% of 90% of our body mass in in our guts? Well, the researchers are Americans...
It's because microbial cells are much smaller then eukaryote cells. Imagine a bunch of basket balls surrounded by BBs.
By mass its probably about two pounds.
Human tissue cells routinely outweigh bacterial cells by more than 100 to 1.
DRM: Terminator crops for your mind!