 |
|
Gut check: Tracking the ecosystem within us
June 26, 2007HHMI study profiles microbes that colonize newborns' GI tracts
For more than 100 years, scientists have known that humans carry a rich ecosystem within their intestines. An astonishing number and variety of microbes, including as many as 400 species of bacteria, help humans digest food, mitigate disease, regulate fat storage, and even promote the formation of blood vessels. By applying sophisticated genetic analysis to samples of a year's worth baby poop, Howard Hughes Medical Institute researchers have now developed a detailed picture of how these bacteria come and go in the intestinal tract during a child's first year of life.
The study, published June 25, 2007, in the journal Public Library of Science (PLoS) Biology, was led by Howard Hughes Medical Institute (HHMI) investigator Patrick O. Brown at the Stanford University School of Medicine.
"I don't know what a human would look like without a colonized gut," said Chana Palmer, the lead author of the new study and a former graduate student in Brown's lab. "The microbiota are important. They help you extract more from your food; they're important for the immune system; and they help protect us from being colonized by [microbes] that are going to do us harm."
Before birth, the human intestinal tract is sterile, but babies immediately begin to acquire the microbial denizens of the gut from their environment -- the birth canal, mothers' breast, and even the touch of a sibling or parent. Within days, a thriving microbial community is established and by adulthood, the human body typically has as many as ten times more microbial cells than human cells. This is primarily due to the large number of microorganisms that have taken up residence in the intestine.
The new study tracked the evolution of the microbial ecosystems in 14 healthy, full-term human infants that were breast fed. Most of the bacteria that live within humans do not thrive in an oxygen-rich environment, and thus are difficult or impossible to grow in culture in the lab. So the researchers turned to DNA microarray technology. That technology, developed by Brown in the 1990s, allows researchers to simultaneously measure the presence or activity of thousands of genes. The team used microarrays to profile the mixture of bacterial DNA in an average of 26 stool samples per infant over the course of the first year of life, beginning with the first stool after birth.
For a handful of these samples, they compared the results that they had obtained using their microarray with the laborious 'gold standard' approach of using genetic libraries of bacteria to get a snapshot of the microbial ecosystem in an infant at a given point in time and found that their new method performed very well.
The results, said Palmer, were striking: the group found that the intestinal microbial communities varied widely from baby to baby - both in terms of which microbes were present and in how that composition changed over time. That finding, she said, is important because it helps broaden the definition of healthy microbial colonization in a baby.
Another intriguing observation, Palmer noted, was a tendency for sudden shifts in the composition of the infants' intestinal microbial communities over time as different species of bacteria ebbed and flowed.
"We don't have a good explanation for why one big group of bacteria would replace another. And it's not that the number of bacteria dropped," Palmer explained. "The size of the population was relatively stable."
Over time, however, the composition of the intestinal microbial communities converged toward a more generic profile characteristic of the adult intestine.
The new study, the authors noted, might bring some clarity to the factors that shape the composition of the microbial communities in the infant intestinal tract. For example, there are conflicting studies about Bifidobacteria, a group of bacterial species reputed to have beneficial effects. Some studies have shown that it is more common in the intestinal tracts of breast-fed infants, but Palmer and Brown's work documented a paucity of those bacteria, although all were breast fed.
The finding that most babies in the study did not acquire significant numbers of Bifidobacteria until several months after birth was a surprise, Palmer said: "That's definitely a contentious area. A lot of studies say they are a major constituent of gut flora beginning shortly after birth."
Putting the study on a firmer footing was the fortuitous inclusion of a pair of fraternal twins, Palmer noted. Although the researchers observed variability within their study, the composition and dynamics of the evolving microbial ecosystems were strikingly similar in the twins. This, Palmer said, provided evidence that genetic and environmental factors shape those ecosystems in reproducible ways. "These data are so rich it is hard to benchmark," she explained. "It's nice to have that check with the twins."
An important general conclusion, said Palmer, is that by the end of the first year of life the intestinal microbial ecosystems assumed a generally similar profile.
"It almost doesn't matter where you start off because we all end up in the same place. There are some bacteria that are really well suited for your gut and they're going to win no matter what."
Howard Hughes Medical Institute
"I don't know what a human would look like without a colonized gut," said Chana Palmer, the lead author of the new study and a former graduate student in Brown's lab. "The microbiota are important. They help you extract more from your food; they're important for the immune system; and they help protect us from being colonized by [microbes] that are going to do us harm."
Before birth, the human intestinal tract is sterile, but babies immediately begin to acquire the microbial denizens of the gut from their environment -- the birth canal, mothers' breast, and even the touch of a sibling or parent. Within days, a thriving microbial community is established and by adulthood, the human body typically has as many as ten times more microbial cells than human cells. This is primarily due to the large number of microorganisms that have taken up residence in the intestine.
The new study tracked the evolution of the microbial ecosystems in 14 healthy, full-term human infants that were breast fed. Most of the bacteria that live within humans do not thrive in an oxygen-rich environment, and thus are difficult or impossible to grow in culture in the lab. So the researchers turned to DNA microarray technology. That technology, developed by Brown in the 1990s, allows researchers to simultaneously measure the presence or activity of thousands of genes. The team used microarrays to profile the mixture of bacterial DNA in an average of 26 stool samples per infant over the course of the first year of life, beginning with the first stool after birth.
For a handful of these samples, they compared the results that they had obtained using their microarray with the laborious 'gold standard' approach of using genetic libraries of bacteria to get a snapshot of the microbial ecosystem in an infant at a given point in time and found that their new method performed very well.
The results, said Palmer, were striking: the group found that the intestinal microbial communities varied widely from baby to baby - both in terms of which microbes were present and in how that composition changed over time. That finding, she said, is important because it helps broaden the definition of healthy microbial colonization in a baby.
Another intriguing observation, Palmer noted, was a tendency for sudden shifts in the composition of the infants' intestinal microbial communities over time as different species of bacteria ebbed and flowed.
"We don't have a good explanation for why one big group of bacteria would replace another. And it's not that the number of bacteria dropped," Palmer explained. "The size of the population was relatively stable."
Over time, however, the composition of the intestinal microbial communities converged toward a more generic profile characteristic of the adult intestine.
The new study, the authors noted, might bring some clarity to the factors that shape the composition of the microbial communities in the infant intestinal tract. For example, there are conflicting studies about Bifidobacteria, a group of bacterial species reputed to have beneficial effects. Some studies have shown that it is more common in the intestinal tracts of breast-fed infants, but Palmer and Brown's work documented a paucity of those bacteria, although all were breast fed.
The finding that most babies in the study did not acquire significant numbers of Bifidobacteria until several months after birth was a surprise, Palmer said: "That's definitely a contentious area. A lot of studies say they are a major constituent of gut flora beginning shortly after birth."
Putting the study on a firmer footing was the fortuitous inclusion of a pair of fraternal twins, Palmer noted. Although the researchers observed variability within their study, the composition and dynamics of the evolving microbial ecosystems were strikingly similar in the twins. This, Palmer said, provided evidence that genetic and environmental factors shape those ecosystems in reproducible ways. "These data are so rich it is hard to benchmark," she explained. "It's nice to have that check with the twins."
An important general conclusion, said Palmer, is that by the end of the first year of life the intestinal microbial ecosystems assumed a generally similar profile.
"It almost doesn't matter where you start off because we all end up in the same place. There are some bacteria that are really well suited for your gut and they're going to win no matter what."
Howard Hughes Medical Institute
Microbes Current Events and Microbes News RSSCigarettes Harbor Many Bacteria Harmful to Human Health
Cigarettes are "widely contaminated" with bacteria, including some known to cause disease in people, concludes a new international study conducted by a University of Maryland environmental health researcher and microbial ecologists at the Ecole Centrale de Lyon in France.
Tiny bubbles clean oil from water
Small amounts of oil leave a fluorescent sheen on polluted water. Oil sheen is hard to remove, even when the water is aerated with ozone or filtered through sand.
MIT scientists pinpoint origin of dissolved arsenic in Bangladesh drinking water
Researchers in MIT's Department of Civil and Environmental Engineering believe they have pinpointed a pathway by which arsenic may be contaminating the drinking water in Bangladesh, a phenomenon that has puzzled scientists, world health agencies and the Bangladeshi government for nearly 30 years.
Earth's early ocean cooled more than a billion years earlier than thought: Stanford study
The scalding-hot sea that supposedly covered the early Earth may in fact never have existed, according to a new study by Stanford University researchers who analyzed isotope ratios in 3.4 billion-year-old ocean floor rocks.
Early life on Earth may have developed more quickly than thought
The Earth's climate was far cooler - perhaps more than 50 degrees - billions of years ago, which could mean conditions for life all over the planet were more conducive than previously believed, according to a research team that includes a Texas A&M University expert who specializes in geobiology.
Sweet as can be: how E. coli gets ahead
Scientists at the University of York have discovered how certain bacteria such as Escherichia coli have evolved to capture rare sugars from their environment giving them an evolutionary advantage in naturally competitive environments like the human gut.
Newly Discovered Fat Molecule: An Undersea Killer with an Upside
A chemical culprit responsible for the rapid, mysterious death of phytoplankton in the North Atlantic Ocean has been found by collaborating scientists at Rutgers University and the Woods Hole Oceanographic Institution (WHOI). This same chemical may hold unexpected promise in cancer research.
New imagining technique could lead to better antibiotics and cancer drugs
A recently devised method of imaging the chemical communication and warfare between microorganisms could lead to new antibiotics, antifungal, antiviral and anti-cancer drugs, said a Texas AgriLife Research scientist.
Nitrogen loss threatens desert plant life, study shows
As the climate gets warmer, arid soils lose nitrogen as gas, reports a new Cornell study. That could lead to deserts with even less plant life than they sustain today, say the researchers.
Scientists visualize how bacteria talk to one another
Using imaging mass spectrometry, researchers at the University of California, San Diego have developed tools that will enable scientists to visualize how different cell populations of cells communicate.
More Microbes Current Events and Microbes News Articles
 |
COMMON COLD GIANT MICROBE PLUSH by Giant Microbes Billions of people a year catch the cold. Now you can get one too -- without getting sick! Learn all about the Common Cold with this cuddly companion. |
 |
GIANT Microbes Plush Doll Swine Flu (Influenza A virus H1N1) by Giant Microbes This little piggy had swine flu, this little piggy had none. Giant Microbes are stuffed 'animals' that look like tiny microbesonly a million times actual size! Each 5-to-7 inch doll is accompanied by an image of the real microbe it represents, as well as information about the microbe. They make great learning tools for parents and educators, as well as amusing gifts for anyone with a sense of humor! |
 |
BRAIN CELL (NEURON) GIANT MICROBES PLUSH by Giant Microbes The more brain cells you have, the smarter you are. |
 |
Giant Microbes E. coli (Escherichia coli) Ailmentaries Plush by Giant Microbes Everyone's welcome at a barbecue. Or are they? |
 |
T4 BACTERIOPHAGE GIANT MICROBES by Giant Microbes The perfect predator, T4 terminates its prey. |
 |
Teaming with Microbes: A Gardener's Guide to the Soil Food Web by Jeff Lowenfels (Author), Wayne Lewis (Author) Teaming With Microbes enlightens readers in two important ways. First, in clear, straightforward language, it describes the activities of the organisms that make up the soil food web, from the simplest of single-cell organisms to more familiar multicellular animals such as insects, worms, and mammals. Second, the book explains how to foster and cultivate the life of the soil through the use of compost, mulches, and compost teas. By eschewing jargon, the authors make the text accessible to a wide audience, from devotees of organic gardening techniques to weekend gardeners who simply want to grow healthy, vigorous plants without resorting to chemicals. |
 |
STOMACH ACHE GIANT MICROBE PLUSH by Giant Microbes Having a stomach ache can be loads of fun ... if it's a Giantmicrobe, of course! (And this one will tell you how to keep his friends away.) |
 |
HERPES (HERPES SIMPLEX VIRUS 2) GIANT MICROBES by Giant Microbes Breaking out is hard to do. Learn the facts. |
 |
MRSA GIANT MICROBES by Giant Microbes You won't find this Superbug in the Halls of Justice. |
 |
PENICILLIN GIANT MICROBES by Giant Microbes Meet the little blue fungus that could. |
| © 2009 BrightSurf.com |