December 13, 2010 The human body is home to a complex ecosystem of microbes increasingly recognized as having a critical role in both health and disease. Viruses can attack and change the composition of bacterial communities, yet little is known about how this might influence human health. In a study published online today in Genome Research (www.genome.org), scientists have performed the first metagenomic analysis of a bacterial immune system in humans over time, finding that the defenses of the oral microbiome are unique and traceable, information that could help personalize oral health care in the future.
With recent advances in sequencing technologies, researchers are now sampling the genetic diversity of entire microbial and viral communities at once, including those residing within us. Recent studies have investigated viral communities of the respiratory and digestive tracts, suggesting that viruses might influence the microbial ecosystem and health of the human host. Less is known about how viruses affect the oral microbiome, which could have significant implications for diseases of the oral cavity.
A strategy for monitoring the interaction between bacterial communities and viruses is to sequence specific bacterial DNA elements that confer acquired immunity against viral attack, called clustered regularly interspaced short palindromic repeats (CRISPRs). Bacteria integrate foreign DNA from encountered pathogens into "spacers" between the repeats, using the spacers to later recognize and respond to the attacker.
In this study, a team of scientists has for the first time analyzed the evolution of the CRISPR bacterial immune system over time in the human body, specifically investigating the oral microbiome. "We knew that bacteria developed specific resistance to viruses," said David Pride of the University of California, San Diego and lead author of the report, "but before this s
|Contact: Peggy Calicchia|
Cold Spring Harbor Laboratory