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."

Comments

Re:can anyone explain this with actual science?

[the_humeister]

Each of your cells takes up 100-1000x more space than bacteria.

Re:can anyone explain this with actual science?

[Anonymous Coward]

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.

Re:can anyone explain this with actual science?

[Qzukk]

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.

Re:A real user...

[Anonymous Coward]

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.

Re:Crohn's Disease

[ColdWetDog]

I've heard it speculated that this could be one of the causes of Crohn's Disease and Colitis. Can anyone here comment on this?

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.

In light of the nature of the pathologic findings in Crohn's disease (see later) and ulcerative colitis, it has long been clear that IBD represents a state of sustained immune response. The question arises as to whether this is an appropriate response to an unrecognized pathogen or an inappropriate response to an innocuous stimulus. Over the decades, many infectious agents have been proposed as the cause of Crohn's disease including Chlamydia, Listeria monocytogenes, cell wall-deficient Pseudomonas species, reovirus, and many others. Paramyxovirus (measles virus) has been implicated etiologically in Crohn's disease as a cause of granulomatous vasculitis and microinfarcts of the intestine[30]; a proposed association between early measles vaccination and Crohn's disease has been largely disproved.[31] Another suggestion has been that the commensal flora, although normal in speciation, possess more subtle virulence factors, such as enteroadherence, that cause or contribute to IBD.[32]

Among the most enduring hypotheses is that Mycobacterium paratuberculosis is the causative agent of Crohn's disease. This notion dates to Dalziel's observation in 1913 that idiopathic granulomatous enterocolitis in humans is similar to Johne's disease, a granulomatous bowel disease of ruminants caused by M. paratuberculosis.[33] M. paratuberculosis is extremely fastidious in its culture requirements, and some proponents of this hypothesis have speculated that the presence of M. paratuberculosis as a spheroplast may confound efforts to confirm the theory. Efforts to confirm this theory have included attempts to culture the organism; demonstrate it by immunohis-tochemistry, in situ hybridization, and polymerase chain reaction methodology; and empiric treatment with antimycobacterial antibiotics. Most investigation in this area has been inconclusive, providing insufficient evidence to either prove or reject the hypothesis.

from Feldman: Sleisenger & Fordtran's Gastrointestinal and Liver Disease, 8th ed.

So sure, maybe. Stay tuned.

Re:Not news

[Daniel Dvorkin]

"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.

Re:the whole division of bacteria into species may

[killtherat]

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.