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Fellow TravelersThe Human Microbiome Project Explores how our Bodies Co-exist with 1 Trillion Foreign Cellsby Ruth SoRelle, M.P.H.
Perhaps the nine of 10 cells (of a total of 100 trillion) in and on your body that are not really yours have some influence on your feelings. Or, maybe not. "They are really tiny," said Richard Gibbs, Ph.D., Director of the Baylor College of Medicine Human Genome Sequencing Center and the College's principal investigator of a new project to sequence the human microbiome. In fact, these "outsider cells" make up no more than 1 to 2 percent of the body's mass and their genomes—their genetic blueprints—are very small as well. The Human Microbiome Project, a Roadmap program of the National Institutes of Health, is designed to sequence the individual bacteria, fungi, parasites and viruses that normally inhabit the various parts of the human body and to "meta-sequence" the communities of bacteria in order to give a picture of the microbial community that colonizes all of us. Understanding the community will give scientists and medical researchers an idea about how changes in those colonies affect health and disease. The project's leaders also plan to look for variations among individuals and different populations. What is the human microbiome?"Each of us are literally immersed, so to speak, in this microbial world. We carry around our own microbial communities within our intestinal tracts, oral cavities, our skin, as well as other areas of the body," said James Versalovic, M.D., Ph.D., Associate Professor of Pathology, Molecular and Human Genetics and Molecular Virology and Microbiology at BCM. He is also Director of Microbiology at Texas Children's Hospital. "We are coated with microbes from top to bottom and within. They have been with us since the beginning through evolution, for thousands of years." In a way, they represent a forgotten organ, he said. "We have this very intimate relationship, and the concept emerging is that these organisms and their genes are performing many important functions in concert with us. We are helping them, and they are helping us. It is a real symbiosis." Most of the human microbiome consists of bacteria, and they inhabit our skin, the mucosa that lines our noses, mouths and other cavities, our guts, and our urinary and vaginal tracts (if we are women). In the "best" of circumstances, the tissues and organs in the body that do not have ready contact with the outside world stay microbe free. Some of these microbes—which also include fungi, viruses and even parasites—are helpful, aiding us in digesting our food, even providing additional nutrients such as vitamins and amino acids and maintaining the proper balance in other areas. "We are coated with microbes from top to bottom and within..." "Their cousins, who cause infections, may be important in medicine, but we are now beginning to understand that most of these microbes—like people—are good," he said. "The Human Microbiome Project is our first major attempt to characterize the organisms and their genes that are part of this human microbiome." Versalovic is a key player in BCM's part of the project along with Sarah Highlander, Ph.D., Associate Professor of Molecular Virology and Microbiology and Joseph Petrosino, Ph.D., an Assistant Professor in the same department, who will lead the College in pushing this effort forward with a $2.3 million "jumpstart" grant from the National Institutes of Health. The metagenomics work will begin with as many as 150 volunteers from whom the researchers will take samples at five body sites: the mouth, the nasal/respiratory tract, the skin, the urogenital tract, and the gastrointestinal tract. Versalovic and Wendy Keitel, M.D., Associate Professor in the Department of Molecular Virology and Microbiology, and Director of the federally funded BCM Vaccine Research Center, will direct the metagenomics sampling effort. Some of the bacteria can grow in culture, though some of the microbes cannot. In those cases, researchers will make whole DNA from the human samples, said Highlander. New technology in the Baylor Human Genome Sequencing Center that allows extremely rapid sequencing of genetic material will play a key role in determining the sequence of genes in the various microbes, she said. For example, the metagenomics sampling of the whole microbiome is only possible because of new technology. "High throughput sequencing has given us the bandwidth to do these kinds of things," Gibbs said. He sees a day when these kinds of techniques will replace or augment older and slower methods of diagnosing infectious diseases. "We want to know every microbe that is out there," said Highlander. "We want to know who is there for healthy adults ages 18 to 40. Later we will compare the microbiomes of people who have different genetic backgrounds or disease states to determine how the microbiome influences or is influenced by these factors. "Once we get through with the reference strain and the metagenomics sequencing, we can move into a lot of comparative analyses," she said. "This could go on for decades." At present, she said, they are working on sequencing the genomes of at least 60 reference strains of bacteria with a current goal of 100. These sequences will serve as a database, or library, to which human microbiome sequences can be compared. "In the end, we hope we can diagnose certain diseases earlier or without as much invasive monitoring, and this will lead to better treatment and prevention," said Petrosino. "In a positive sense, this is like the space program for human health," he said. "Not only will the endpoints give us tools to prevent and treat human disease, but the techniques we develop along the way can be applied in a variety of fields, including infectious diseases, proteomics and high throughput microbiology." |
FeaturesTreatments on the Horizon: Chapter and Verse on a Brain Killer Two Brains are Better than One SpotlightCaring for Community at Home and Abroad Injecting a Little Scientist in Every Doctor Designing a Building in the Eyes of a Researcher Laser Treatments Best Left up to Doctors BriefsFalls in Elderly Indicate Illness Findings may Increase Survival after Injuries Some Like it Hot! Structure of Receptor for Chili Pepper and Pain Revealed Beware of Drinking Margaritas in the Sun Development/AlumniBCM Family Participates in Fundraising Campaign BCM Alums take D.C. Fellowships Seed Funding Leads to Breakthroughs Father, Daughter Team up for Health Care
Steps to Discovery and Innovation
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Volume 4, Issue 2, Summer 2008 |
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| Last modified: October 7, 2008 |
Are there days when you do not really feel like yourself?