Your Feces Is a Wonderland of Viruses

sciencehabit writes "Thanks to an anlaysis of fecal samples from four sets of Missouri-born female identical twins and their mothers, researchers have concluded that human guts harbor viruses as unique as the people they inhabit; the viral lineup differs even between identical twins. Even more surprising? These viruses may be doing good work inside of us."

Comments

Re:Evolution

[sznupi]

So you haven't ever heard about parasites or, more generally, infections of all kind? Sure, it's a matter of finding a balance for bost host and "attackers" to survive, but it doesn't mean the latter "doing something bad inside of us" aren't present (of course together with those which are pretty much neutral (but good but taking resources from "bad") or outright "good")

Just be glad you're not an elephant

[OrangeMonkey11]

Humans are born with all these bacteria built into the body and advances as we grew up; on the other hand young elephant have to eat their parents feces in order to gain these valuable bacteria to help them have an immune system and digest food.

So aren't you glad you're not an elephant.

Re:Just be glad you're not an elephant

[PCM2]

Actually, humans spend the nine months in utero in a completely bacteria-free environment. However, babies born vaginally pick up their first dose of bacteria immediately as they emerge from their mother's birth canal, and even babies born via Caeserian section are bacteria magnets. The natural birth babies generally get a big dose of lactobacillus, while C-section babies tend to pick up strains found on the skin and the general hospital environment. Or so they say. But the bacteria are hardly "built into the body," which is why identical twins will have different gut flora.

Still, you may notice that TFA is about viruses, not bacteria.

Re:Just be glad you're not an elephant

[Anonymous Coward]

I am an ICU nurse and was shocked the first time the doctor ordered a "fecal transplant." This is for someone who has been on so many antibiotics that they have depleted the bacteria in their gut. Feces is collected from family members, processed, and "transplanted" to the patient via a feeding tube. It is not common or palatable but effective.

Re:Just be glad you're not an elephant

[Anonymous Coward]

Humans are born with all these bacteria built into the body and advances as we grew up; on the other hand young elephant have to eat their parents feces in order to gain these valuable bacteria to help them have an immune system and digest food.

So aren't you glad you're not an elephant.

As a microbiologist in studying the gut microbiota, I can tell you that this is 100% wrong, no-one is born with bacteria built into them, in fact gnotobiotic animals, ones completely free of all bacteria and viruses are (somewhat easily) made by C-section in a sterile environment for the purposes of gut and nutrition research all the time. These animals are difficult to maintain, however, because they essentially must live like the "boy in the bubble" all their food and water, as well as all the tools used for their examination must be sterilized ( food is typically irradiated up to 5 times to make sure all the stuff in it is dead) to keep them from being contaminated, and facilities that maintain these animals must be built specifically for this task - which is not exactly cheap. *** As an aside, please keep in mind that even ignoring the subject of virii transferring DNA within the bacterial soup, some scientists estimate that to date we have sequenced and discovered less than 1% of all the bacterial species in the human gut even with massive throughput technologies like pyrosequencing. *** Also keep in mind that at the moment, we (scientists) still have not come to a consensus about what a unique bacterial (or viral, if they are even alive) species is! In other words, while nicely defined terms work for the rest of the living stuff on this planet, ( if you can produce viable offspring with another organism, then you are the same species) this does not apply to bacteria or viruses because they reproduce asexually. All we have to go on as far as classification is the DNA sequences of all these microorganisms, and how similar those sequences are to others - so where does one draw the line and say "this is a new species" ? At >3% difference? at >1% , or something else? People can't agree on this because what ends up happening is you end up finding two bacteria that are 99% identical but behave completely differently, while another pair of two supposedly different species are functionally/metabolically indistinguishable. *** Oh and to shed some light on the deal with identical twins: basically everyone is right, diet, location, lifestyle (smoking/ drinking vs. not, working in a sewer, etc.) AND host genetics all play important roles in what bacteria end up permanently colonizing a persons intestine. To elaborate, two identical twins separated at birth, eating different things will still be more similar to each other than would a pair of two complete strangers. If these twins lived in the same house and had similar diets, they would be even MORE similar than if they were separated, but never identical. At the same time, a pair of complete strangers living in the same house and eating the same things would be more similar than if they lived separately and had different diets. **** Fun fact: twins also have different fingerprints

Re:Just be glad you're not an elephant

[priegog]

Yeah, I'm sorry to burst your bubble, but as a couple of people already pointed out, we actually do get our colonic flora from our mothers' (most of the time) poo (or perineal region, which is essentially the same thing). Of course all throughout our lives it gets modified by our own immune system makeup, eating habits, antibiotic use, etc... But the bacteria that protect us on those first few days/weeks/months come DIRECTLY out of our moms' butts.

Re:Just be glad you're not an elephant

[instagib]

I couldn't believe this, but it's true. Mod parent up more.

Lack of control groups in study

[Tisha_AH]

The article mentions the identical twins but it does not indicate if they are adult, identical twins living in different places, with different environmental conditions. If you took two 25 year old identical twins and raised one in Florida and the other in Seattle for five years you would definitely find different flora in the gut.

Now if these identical twins were still children, raised in the same environment, then that would indeed be interesting.

Re:Yea, and?

[msauve]

No, they're discussing viruses and bacteria. Nowhere do they use the incorrect term "virii" in a failed attempt to look intelligent.

Re:So what we are anyway?

[mdielmann]

We comprise about 1% by weight of bacteria. Given the small size of bacteria cells, we have 10 times the bacterial cells to "human" cells. Here's where you can start reading.
And then there's mitochondria, which look a lot more like foreign microbes within our own cells than just a structure built by our cell, complete with their own DNA.
It is correct that much of those bacteria live in your gut, but apparently skin has its fair share, too. Nonetheless, those gut bacteria are also vital to the proper function of your body.

HGT and Bacteriophages

[interactive_civilian]

Well, it's not inside all of us, guessing by the article. It differs between all of us, and besides, people generally think of viruses as bad things. Bacteria, yes, but I can't really think of very useful viruses.

Bacteriophages can transfer new traits to bacteria, across species (and even across domains) and is a very important means of horizontal gene transfer. Sure, this may not be "useful" to us, who so often have to combat these new traits such as the various antibiotic resistances that arise, but it is certainly useful to the bacteria. Even in the article, they suggested that the helpfulness of these gut viruses is to the bacteria rather than directly to the human.

For people who study microbiology and especially microbiological evolution (for the record, I am not; I'm just an interested bystander), the idea of symbiotic viruses is not surprising.

Re:So what we are anyway?

[sznupi]

Ehhh...fine, then "inert" is cleary not appropriate, happy?

And c'mon, very quick & easy search brings two sources of very nice, solid references (also journals)
http://en.wikipedia.org/wiki/Human_flora
http://en.wikipedia.org/wiki/Gut_flora

At least 10 times more cells, when counting only gut bacteria (10^14 vs. 10^13 human ones in the body); also, "It is estimated that these gut flora have around 100 times as many genes in aggregate as there are in the human genome."

Do you have any more ridiculous problems?