Dirty Skin

[Gary]

Human skin populated by veritable zoo of bacteria

By Will Dunham

WASHINGTON (Reuters) - Researchers on a safari for microbes have found that human skin is populated by a veritable menagerie of bacteria -- 182 species -- some apparently living there permanently and others just dropping by for a visit.

There's no need for alarm, said microbiologist Dr. Martin Blaser of New York University School of Medicine: the bacteria have been with us for quite a while and some are helpful.

In research published on Monday in the Proceedings of the National Academy of Sciences, Blaser and his colleagues took swabs from the forearms of six healthy people to study the bacterial populations in human skin -- our largest organ.

"We identify about 182 species," Blaser said in an interview. "And based on those numbers, we estimate there are probably at least 250 species in the skin."

"In comparison," Blaser added, "a good zoo might have 100 species or 200 species. So we already know that there are as many different species in our skin, just on the forearm, as there are in a good zoo."

Bacteria are single-celled microorganisms believed to have been the first living things on Earth. While some cause disease, bacteria also reside normally in our bodies, for example in the digestive tract, performing useful chores.

"Without good bacteria, the body could not survive," added Dr. Zhan Gao, a scientist in Blaser's lab involved in the study.

The researchers noted that microbes in the body actually outnumber human cells 10-to-1.

"Our microbes are actually, in essence, a part of our body," Blaser said.

"We think that many of the normal organisms are protecting the skin. So that's why I don't think it's a great idea to keep washing all the time because we're basically washing off one of our defense layers," Blaser added.

SOPHISTICATED TECHNIQUE

It has long been known that bacteria reside in the skin, but Blaser and his colleagues used a sophisticated molecular technique based on DNA to conduct a rigorous census.

The inhabitants proved to be more diverse than had been thought, with about 8 percent of the species previously unknown, the researchers found.

Some bacteria seemed to be permanent residents of the skin, with four genera -- Staphylococcus, Streptococcus, Propionibacteria and Corynebacteria -- accounting for a bit more than half the population. Others were more transient.

In each person, the population of bacteria changed over time although a core set existed for each.

The volunteers included three men and three women, and the findings suggested the two sexes may differ in the bacteria they tote along.

The researchers previously had studied bacteria in the stomach and esophagus. With this research, they found that the insides of the body and the skin had major differences in bacterial populations.

"Microbes have been living in animals probably for a billion years. And the microbes that we have in our body are not accidental. They have evolved with us," Blaser said.

http://news.yahoo.com/s/nm/20070205/sc_ ... acteria_dc

[Ted]

One day put your pillow under an Electron microscope--Sweet dreams

[Teresa B]

One day put your pillow under an Electron microscope--Sweet dreams

Yeah, but imagine what nightmares the microbes would have if they could see US.

Teresa

[Ralph]

Bacteria is only skin deep. Nope, that doesn't work.

[Ted]

I think in Ralph and Teresa we may have the new Nichols & May
****

[RebLem]

So, that's why my dog likes to lick me so much !

[Ted]

Good Bedfellows?

[BWV 1080]

Bacteria are us!
Biologist Lynn Margulis, asked by The Edge, what is her most dangerous idea:

Bacteria are us

What is my dangerous idea? Although arcane, evidence for this dangerous concept is overwhelming; I have collected clues from many sources. Reminiscent of Oscar Wilde's claim that "even true things can be proved" I predict that the scientific gatekeepers in academia eventually will be forced to permit this dangerous idea to become widely accepted. What is it?

Our sensibilities, our perceptions that register through our sense organ cells evolved directly from our bacterial ancestors. Signals in the environment: light impinging on the eye's retina, taste on the buds of the tongue, odor through the nose, sound in the ear are translated to nervous impulses by extensions of sensory cells called cilia. We, like all other mammals, including our apish brothers, have taste-bud cilia, inner ear cilia, nasal passage cilia that detect odors. We distinguish savory from sweet, birdsong from whalesong, drumbeats from thunder. With our eyes closed, we detect the light of the rising sun and and feel the vibrations of the drums. These abilities to sense our surroundings, a heritage that preceded the evolution of all primates, indeed, all animals, by use of specialized cilia at the tips of sensory cells, and the existence of the cilia in the tails of sperm, come from one kind of our bacterial ancestors. Which? Those of our bacterial ancestors that became cilia. We owe our sensitivity to a loving touch, the scent of lavender , the taste of a salted nut or vinaigrette, a police-cruiser siren, or glimpse of brilliant starlight to our sensory cells. We owe the chemical attraction of the sperm as its tail impels it to swim toward the egg, even the moss plant sperm, to its cilia. The dangerous idea is that the cilia evolved from hyperactive bacteria. Bacterial ancestors swam toward food and away from noxious gases, they moved up to the well-lit waters at the surface of the pond. They were startled when, in a crowd, some relative bumped them. These bacterial ancestors that never slept, avoided water too hot or too salty. They still do.

Why is the concept that our sensitivities evolved directly from swimming bacterial ancestors of the sensory cilia so dangerous?

Several reasons: we would be forced to admit that bacteria are conscious, that they are sensitive to stimuli in their environment and behave accordingly. We would have to accept that bacteria, touted to be our enemies, are not merely neutral or friendly but that they are us. They are direct ancestors of our most sensitive body parts. Our culture's terminology about bacteria is that of warfare: they are germs to be destroyed and forever vanquished, bacterial enemies make toxins that poison us. We load our soaps with antibacterials that kill on contact, stomach ulcers are now agreed to be caused by bacterial infection. Even if some admit the existence of "good" bacteria in soil or probiotic food like yogurt few of us tolerate the dangerous notion that human sperm tails and sensitive cells of nasal passages lined with waving cilia, are former bacteria. If this dangerous idea becomes widespread it follows that we humans must agree that even before our evolution as animals we have hated and tried to kill our own ancestors. Again, we have seen the enemy, indeed, and, as usual, it is us. Social interactions of sensitive bacteria, then, not God, made us who were are today.

http://www.edge.org/q2006/q06_7.html#margulis

[Agnes Selby]

One day put your pillow under an Electron microscope--Sweet dreams

Yeah, but imagine what nightmares the microbes would have if they could see US. -

Teresa

---------------

Dear Teresa,

Thank you for giving me something to chuckle about.



Agnes.
--------------------------

[Ralph]

One day put your pillow under an Electron microscope--Sweet dreams

Yeah, but imagine what nightmares the microbes would have if they could see US.

Teresa

*****

Actually, several of them post here regularly.

[Brendan]

One day put your pillow under an Electron microscope--Sweet dreams

Yeah, but imagine what nightmares the microbes would have if they could see US.

Teresa

*****

Actually, several of them post here regularly.

The microbes, the nightmares (the pillows?) or, well, us?

[piston]

One day put your pillow under an Electron microscope--Sweet dreams

Yeah, but imagine what nightmares the microbes would have if they could see US.

Teresa

*****

Actually, several of them post here regularly.

The microbes, the nightmares (the pillows?) or, well, us?

I'm all for diversity: micro-cobes, macro-cobes, hetero-cobes and homo-cobes.

[Gary]

Bacteria are us!

Then I'm spraying myself with Lysol.