Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Tuberculosis genomes portray secrets of pathogen's success

By any measure, tuberculosis (TB) is a wildly successful pathogen. It infects as many as two billion people in every corner of the world, with a new infection of a human host estimated to occur every second.

Now, thanks to a new analysis of dozens of tuberculosis genomes gathered from around the world, scientists are getting a more detailed picture of why TB is so prevalent and how it evolves to resist countermeasures. Writing today (Aug. 21, 2013) in the journal Public Library of Science (PLoS) Pathogens, a team led by University of Wisconsin-Madison researcher Caitlin Pepperell describes a bacterium that marches in lockstep with human population growth and history, evolving to take advantage of the most crowded and wretched human conditions.

"It's as though the bacterium places bets on human behavior," says Pepperell, formerly of Stanford University, and now a professor of medicine and medical microbiology at UW-Madison. "It always bets that humans will go to war, send people to refugee camps, and gather in miserable places. Historically, that's been a winning bet on the bacterium's part."

The PLoS Pathogens study, whose senior author is Marcus Feldman of Stanford, reveals that tuberculosis experienced a 25-fold expansion worldwide in the 17th century, a time when human populations underwent explosive growth and European exploration of Africa, the Americas, Asia and Oceania was at its peak.

"The timing is coincident with expansion, urbanization and colonial migrations of global human populations," Pepperell explains. "These findings suggest that much of the current TB pandemic has its origins in historical events of the last three centuries."

TB is only transmitted by people, and the organism cannot survive in the environment. It thrives, however, in the crowded conditions of prisons, refugee camps and slums, and TB populations tend to be dominated by the bacteria "lucky" enough to land in those environments.

The analysis conducted by Pepperell and her colleagues focused on the role of natural selection, looking at patterns of genetic diversity among 63 TB and related pathogenic mycobacterial genomes gathered from around the globe.

The study shows a highly constrained bacterial genome, with most deleterious mutations quickly discarded. This was especially true for genes essential for causing disease, protein translation and the trafficking and metabolism of inorganic ions, which help control the interaction between the TB pathogen and its human host.

The bacterium's "defense" genes, on the other hand, showed a high degree of tolerance for beneficial mutations, which may play a role in evolution of drug resistance and evasion of the human immune system.

Pepperell notes: "Evolutionary theory predicts that Mycobacterium tuberculosis populations should be vulnerable to extinction. Yet it is obviously highly prevalent. It must have some incredibly clever strategies and tricks to hang on."

As a result, the explosive spread of TB parallels the growth of human populations and takes every advantage of a world where most people live in crowded and impoverished conditions.

The study, according to Pepperell, should help other researchers home in on genes that may be good candidates for targeting with new drugs, and aid disease control strategies that accommodate or even co-opt the bacterium's evolution and help drive its extinction.

In addition to Pepperell and Feldman, co-authors of the new study include Amanda Casto, Julie Granka and Omar Cornejo of Stanford; Andrew Kitchen of the University of Iowa; Eddie Holmes of the University of Sydney; and Bruce Birren and James Galagan of the Broad Institute.

—Terry Devitt, 608-262-8282,

Caitlin Pepperell | EurekAlert!
Further information:

More articles from Health and Medicine:

nachricht Resolving the mystery of preeclampsia
21.10.2016 | Universitätsklinikum Magdeburg

nachricht New potential cancer treatment using microwaves to target deep tumors
12.10.2016 | University of Texas at Arlington

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>