Featured Research

from universities, journals, and other organizations

Major Differences Found Between Genomes Of Oral Pathogen And Related Spiral-shaped Bacteria That Cause Syphilis And Lyme Disease

Date:
April 2, 2004
Source:
The Institute For Genomic Research
Summary:
Three centuries after a pioneering Dutch microbiologist first observed the spiral-shaped oral pathogen Treponema denticola, scientists have deciphered the bacterium's entire DNA sequence and used comparative genomics to cast new light on other spirochete microbes.

Rockville, MD – Three centuries after a pioneering Dutch microbiologist first observed the spiral-shaped oral pathogen Treponema denticola, scientists have deciphered the bacterium's entire DNA sequence and used comparative genomics to cast new light on other spirochete microbes.

Related Articles


The study by scientists at The Institute for Genomic Research (TIGR) and collaborators at Baylor College of Medicine and the University of Texas Health Science Center at Houston found profound differences between the gene content of T. denticola, which is associated with periodontal (gum) disease, and of other spirochetes that cause syphilis and Lyme disease.

"This highlights the power of comparative genomics to help us understand how related pathogens can cause completely different diseases," says Ian Paulsen, who led the sequencing along with fellow TIGR researcher Rekha Seshadri. Paulsen says the T. denticola genome "provides an excellent point of reference to study the biology of spirochetes."

The paper will appear in the April 13, 2004 issue of Proceedings of the National Academy of Sciences (PNAS) and was scheduled to be published online this week. The study was supported by the National Institute of Dental and Craniofacial Research (NIDCR), which is part of the U.S. National Institutes of Health.

The researchers found that T. denticola has more than twice as many genes as the spirochete that causes syphilis, T. pallidum, and that there is virtually no conservation of gene order (synteny) between the genomes of the two related microbes. The authors say that indicates that the two spirochetes' divergence from a common ancestor "was an ancient event" in contrast to the more recent divergence of many other groups of bacteria from their ancestral relatives.

The genome study is expected to help scientists find out more about how oral pathogens interact in dental plaque to cause gum disease. T. denticola tends to aggregate in such subgingival plaque with Porphyromonas gingivalis, a bacterium that is associated with periodontitis, a gum disease that affects an estimated 200 million Americans. Having the complete genomes of both microbes will help researches study their interactions and possibly provide molecular clues to find targets for drugs to treat gum disease.

TIGR scientists and collaborators sequenced the genome of P. gingivalis last year and are now deciphering the genomes of six other oral-cavity bacteria and conducting a "meta-genomic" assay of mouth microbes. Of the estimated 500 microbial species in the human mouth, only about 150 species have been cultured in laboratories.

"The genome sequence reveals mechanisms used by T. denticola to colonize and survive in the complex environment of oral biofilms," says Seshadri, the study's first author. TIGR's collaborators in the PNAS study included Steven J. Norris at the UT Health Science Center at Houston and George M. Weinstock at Baylor College of Medicine's Department of Molecular and Human Genetics.

In the PNAS paper, researchers reported that the genome of T. denticola "reflects its adaptations for colonization and survival" with other bacteria in plaque. Compared to other spirochetes (including an estimated 60 other treponomal species or phylotypes found in dental plaque), T. denticola is relatively easy to cultivate and manipulate genetically, making it an excellent model for spirochete research.

Spirochetes are distinguished by their spiral shapes and their ability to corkscrew their way through gel-like tissues, causing a number of different diseases. The father of microbiology, Antonie van Leeuwenhoek, had first sketched an oral spirochete – later named T. denticola – after viewing it through his primitive microscope in the 1670s. Even after three centuries, however, spirochetes are poorly understood in contrast to many other major types of bacteria.

So far, TIGR has sequenced the complete genomes of three spirochetes: T. denticola; T. pallidum, which causes syphilis; and Borellia burgdorferei, which causes Lyme disease. The genome of a fourth spirochete, Leptospira interrogans, which causes the disease Leptosporisis, was sequenced at the Chinese National Human Genome Center.

TIGR's comparative analysis found that about half of T. denticola's 2,786 genes are not present in the other three sequenced spirochetes. The 618 genes that all four spirochetes have in common include some genes that are not found in other types of microbes whose genomes have been sequenced.

"Having the genome sequences of several spirochetes provides a remarkable opportunity to study evolution," says Norris, who says all spirochetes are cousins even though they live in a wide variety of environments, including mud, clams, termite guts, ticks, and humans. By comparing the DNA sequences of more spirochetes, he says, "we may be able to get at the root of what makes a bacterium cause disease, live free in the environment, or even be beneficial to its host."

Claire M. Fraser, president of TIGR, says the sequence data "provide a new starting point" for exploring the molecular differences that may explain why and how T. denticola and T. pallidum cause such different diseases: "This study has revealed new insights into spirochete-specific biology as well as the evolutionary forces that have shaped these genomes."

###

The Institute for Genomic Research (TIGR) is a not-for-profit research institute based in Rockville, Maryland. TIGR, which sequenced the first complete genome of a free-living organism in 1995, has been at the forefront of the genomic revolution since the institute was founded in 1992. TIGR conducts research involving the structural, functional, and comparative analysis of genomes and gene products in viruses, bacteria, archaea, and eukaryotes.

Seshadri et al. (2004). Comparison of the genome of the oral pathogen Treponema denticola with other spirochete genomes. Proc Natl Acad Sci. [Scheduled for print publication in issue dated April 13, 2004. Manuscript No. 2003-07639]


Story Source:

The above story is based on materials provided by The Institute For Genomic Research. Note: Materials may be edited for content and length.


Cite This Page:

The Institute For Genomic Research. "Major Differences Found Between Genomes Of Oral Pathogen And Related Spiral-shaped Bacteria That Cause Syphilis And Lyme Disease." ScienceDaily. ScienceDaily, 2 April 2004. <www.sciencedaily.com/releases/2004/03/040330090454.htm>.
The Institute For Genomic Research. (2004, April 2). Major Differences Found Between Genomes Of Oral Pathogen And Related Spiral-shaped Bacteria That Cause Syphilis And Lyme Disease. ScienceDaily. Retrieved November 24, 2014 from www.sciencedaily.com/releases/2004/03/040330090454.htm
The Institute For Genomic Research. "Major Differences Found Between Genomes Of Oral Pathogen And Related Spiral-shaped Bacteria That Cause Syphilis And Lyme Disease." ScienceDaily. www.sciencedaily.com/releases/2004/03/040330090454.htm (accessed November 24, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Monday, November 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Winter Can Cause Depression — Here's How To Combat It

Winter Can Cause Depression — Here's How To Combat It

Newsy (Nov. 23, 2014) Millions of American suffer from seasonal depression every year. It can lead to adverse health effects, but there are ways to ease symptoms. Video provided by Newsy
Powered by NewsLook.com
Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

AFP (Nov. 23, 2014) The arable district of Kenema in Sierra Leone -- at the centre of the Ebola outbreak in May -- has been under quarantine for three months as the cocoa harvest comes in. Duration: 01:32 Video provided by AFP
Powered by NewsLook.com
Don't Fall For Flu Shot Myths

Don't Fall For Flu Shot Myths

Newsy (Nov. 23, 2014) Misconceptions abound when it comes to your annual flu shot. Medical experts say most people older than 6 months should get the shot. Video provided by Newsy
Powered by NewsLook.com
WFP: Ebola Risks Heightened Among Women Throughout Africa

WFP: Ebola Risks Heightened Among Women Throughout Africa

AFP (Nov. 21, 2014) Having children has always been a frightening prospect in Sierra Leone, the world's most dangerous place to give birth, but Ebola has presented an alarming new threat for expectant mothers. Duration: 00:37 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins