we're mostly Microbes - implications?

[Guest guest]

The following Washington Post article from today

describes results reported in the current PNAS

(abstract below) and indicates " Microbiomes " in

our bodies could be a " 2nd Human Sequencing

project " . Such new information is hoped to

enhance approaches for better health through

optimization of our interactions with, and use of, 'our' microbiomes.

Understanding of the microbes that inhabit the

human body is not a new interest. The concept of

" probiotics " has existed for decades for both

animal & human health improvements; however, the

tools for study of microbiomes have evolved to

increase the probability for achieving improvements.

Al Janski

------

Human body is mostly itsy-bitsy microbes, new research finds

By Rob Stein

WASHINGTON POST

Tuesday, Feb. 13 2007

Hold out your hand, with the palm facing skyward.

Now take a look at the fleshy

part of your arm, about halfway between your wrist and elbow. What do you see?

Nothing, probably.

But that's not what J. Blaser, of New York University School of

Medicine, sees. With the help of the latest scientific tools, Blaser sees a

complex, microscopic world teeming with a vast array of microorganisms.

" The skin is home to a virtual zoo, " said Blaser, a microbiologist who last

week published online the first molecular analysis of the bacteria living on

one small patch of human skin. " We're just beginning to explore it. "

The analysis revealed that human skin is populated by a diverse assortment of

bacteria, including many previously unknown species, offering the first

detailed peek at this potentially crucial ecosystem.

The work is part of a broader effort by a small

coterie of scientists to better

understand the microbial world that populates the human body. Virtually every

orifice and the digestive tract are swarming with bacteria, fungi and other

microbes. By some estimates, only one out of every 10 cells in the body is

human.

Scientists suspect these microbes play important but poorly understood roles,

assisting crucial bodily functions and potentially helping prevent or cause

many diseases.

" This type of work is setting the stage for a

second human sequencing project ­

one that examines our microbiomes " ­ the genes of the microbial communities

populating our bodies ­ Gordon, of Washington University in St. Louis

wrote in an e-mail. Gordon reviewed Blaser's paper for publication by the

Proceedings of the National Academy of Sciences.

Such a project could lead " to new ways of defining health, new ways for

predicting disease predilection, and new ways for treating illnesses affecting

various components of our body, including the skin. "

Blaser's team swabbed an area of skin on the right and left forearms of three

healthy men and three healthy women. They then used molecular techniques to

analyze fragments of bacterial DNA captured by the swabs.

The analysis revealed 182 species, the researchers reported. Of those, 30 had

never been seen. They identified an additional 65 species when they sampled

four of the volunteers eight to 10 months later, including 14 new species.

The next step will be to try to characterize the organisms' functions. " We're

interested in understanding how we interact with these organisms and how they

are communicating with human cells and vice versa, " Blaser said.

http://www.stltoday.com/stltoday/news/stories.nsf/nation/story/6856A9B50FA1E7F38\

6257281001061AC?OpenDocument & highlight=2%2C%22microbes%22

-------

Proc Natl Acad Sci U S A. 2007 Feb 9; [Epub ahead of print]

Molecular analysis of human forearm superficial skin bacterial biota.

Gao Z, Tseng CH, Pei Z, Blaser MJ.

Departments of Medicine, Environmental Medicine,

Pathology, and Microbiology, New York University

School of Medicine, New York, NY 10016.

The microbial ecology of human skin is complex,

but little is known about its species

composition. We examined the diversity of the

skin biota from the superficial volar left and

right forearms in six healthy subjects using

broad-range small subunit rRNA genes (16S rDNA)

PCR-based sequencing of randomly selected clones.

For the initial 1,221 clones analyzed, 182

species-level operational taxonomic units

(SLOTUs) belonging to eight phyla were

identified, estimated as 74.0% [95% confidence

interval (C.I.), approximately 64.8-77.9%] of the

SLOTUs in this ecosystem; 48.0 +/- 12.2 SLOTUs

were found in each subject. Three phyla

(Actinobacteria, Firmicutes, and Proteobacteria)

accounted for 94.6% of the clones. Most (85.3%)

of the bacterial sequences corresponded to known

and cultivated species, but 98 (8.0%) clones,

comprising 30 phylotypes, had <97% similarity to

prior database sequences. Only 6 (6.6%) of the 91

genera and 4 (2.2%) of the 182 SLOTUs,

respectively, were found in all six subjects.

Analysis of 817 clones obtained 8-10 months later

from four subjects showed additional phyla

(numbering 2), genera (numbering 28), and SLOTUs

(numbering 65). Only four (3.4%) of the 119

genera (Propionibacteria, Corynebacteria,

Staphylococcus, and Streptococcus) were observed

in each subject tested twice, but these genera

represented 54.4% of all clones. These results

show that the bacterial biota in normal

superficial skin is highly diverse, with few well

conserved and well represented genera, but

otherwise low-level interpersonal consensus.