Genome decoding of the medieval leprosy pathogen

The comparison of 1,000-year-old and modern bacterial genomes provides insights into the disease history

2013-06-14

(Press-News.org) From skeletons and biopsies, an international team of scientists was successful in reconstructing a dozen medieval and modern genomes of the leprosy-causing bacteria Mycobacterium leprae. Under the direction of Professor Johannes Krause, University of Tübingen, and Professor Stewart Cole, Swiss Federal Institute of Technology of Lausanne (EPFL), the research group created a genome from archaeological finds for the first time without having to resort to a reference sequence. Professor Almut Nebel and Dr. Ben Krause-Kyora, both of the Institute of Clinical Molecular Biology, Kiel University, belong to the team, whose findings are to be published this week in Science magazine.

Leprosy, a devastating infectious and chronic disease, was widespread in Europe until the Late Middle Ages. Persons infected with the disease were isolated in leprosy colonies specifically built for the patients. Today, the disease is found in 91 countries worldwide with more than 200,000 new infections per year. In order to trace the history of the disease, the scientists reconstructed the complete genomes of M. leprae from five medieval skeletons from Denmark, Sweden and Great Britain. These specimens exhibited the characteristic bone changes associated with leprosy. Additionally, the M. leprae genetic substance was decoded from seven biopsy samples of contemporary patients.

The researchers compared the European medieval M. leprae genome with those of the seven biopsies and four additional modern bacteria strains. They observed that all M. leprae strains have a common ancestor that existed less than 4000 years ago. This result is supported by the earliest archaeological evidence of the disease in India. The genome-wide comparisons suggest unusually minor changes of the bacteria's genetic material within the last 1000 years, which presumably had no effects on the virulence of the pathogen. This evidence suggests that the end of the leprosy epidemic was influenced by other factors such as improved social conditions during the Middle Ages. The research team also demonstrated that a form of M. leprae, which existed in Europe during the Middle Ages, can currently be observed in the Middle East. Another medieval strain from Europe has striking similarities to bacteria that are currently identified in armadillos and leprosy patients in North America, pointing to a European origin of the disease in America.

Surprisingly, a much larger amount of pathogen DNA was observed in the examined skeletons than is usually found in contemporary patients. The researchers ascribe this phenomenon to the circumstance that the bacterial DNA probably decomposes very slowly as a result of the extremely thick cell wall of the leprosy bacterium, thus enabling its accumulation in the skeletons over time. "This makes it possible that certain forms of bacterial DNA remain preserved above the maximal age for mammalian DNA, which is approximately one million years", stated Johannes Krause. "Thus, it should be possible to trace the disease back to its prehistoric origins."

"The DNA of the pathogen was particularly well-preserved in a skeleton from Denmark, although the disease was not strongly pronounced in the ca. 25-year-old woman", commented Almut Nebel. This DNA sample enabled the assembly of an ancient pathogen from scratch for the first time without comparison to a reference sequence. "We have contacted the Danish colleagues who provided us with the important skeletons for the investigation. The DNA was extracted from the teeth of the lepers and subsequently subjected to a first molecular feasibility test", mentioned Ben Krause-Kyora. Moreover, the researchers in Kiel repeated the investigations of their colleagues from Tübingen in order to independently demonstrate the exceptional results. The research project in Kiel was supported by the Graduate School Human Development in Landscapes and the Cluster of Excellence `Inflammation at Interfaces´.

INFORMATION:

Original publication:

The history of leprosy from genome-wide comparison of medieval and modern Mycobacterium leprae, Verena J. Schuenemann, Pushpendra Singh, Thomas A. Mendum, Ben Krause-Kyora, Günther Jäger, et al., Science

ELSE PRESS RELEASES FROM THIS DATE:

Automated 'coach' could help with social interactions

2013-06-14

CAMBRIDGE, MA -- Social phobias affect about 15 million adults in the United States, according to the National Institute of Mental Health, and surveys show that public speaking is high on the list of such phobias. For some people, these fears of social situations can be especially acute: For example, individuals with Asperger's syndrome often have difficulty making eye contact and reacting appropriately to social cues. But with appropriate training, such difficulties can often be overcome. Now, new software developed at MIT can be used to help people practice their interpersonal ...

Berkeley Lab team uncovers secrets of biological soil crusts

2013-06-14

They lie dormant for years, but at the first sign of favorable conditions they awaken. This sounds like the tagline for a science fiction movie, but it describes the amazing life-cycles of microbial organisms that form the biological soil crusts (BSCs) of Earth's deserts. Now a research team with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) has reported a unique molecular-level analysis of a BSC cyanobacterium responding to the wetting and drying of its environment. The results hold implications for land management, improved ...

Researchers unearth bioenergy potential in leaf-cutter ant communities

2013-06-14

MADISON-— As spring warms up Wisconsin, humans aren't the only ones tending their gardens. At the University of Wisconsin–Madison Department of Bacteriology, colonies of leaf-cutter ants cultivate thriving communities of fungi and bacteria using freshly cut plant material. While these fungus gardens are a source of food and shelter for the ants, for researchers, they are potential models for better biofuel production. "We are interested in the whole fungus garden community, because a lot of plant biomass goes in and is converted to energy for the ants," says Frank ...

Scientists at UMass Medical School identify neurons that control feeding behavior in Drosophila

2013-06-14

WORCESTER – Scientists at the University of Massachusetts Medical School have developed a novel transgenic system which allows them to remotely activate individual brain cells in the model organism Drosophila using ambient temperature. This powerful new tool for identifying and characterizing neural circuitry has lead to the identification of a pair of neurons – now called Fdg neurons – in the fruit fly that decide when to eat and initiate the subsequent feeding action. Discovery of these neurons may help neurobiologists better understand how the brain uses memory and stimuli ...

UCLA climate study predicts dramatic loss in local snowfall

2013-06-14

By midcentury, snowfall on Los Angeles–area mountains will be 30 to 40 percent less than it was at the end of the 20th century, according to a UCLA study released today and led by UCLA climate expert Alex Hall. The projected snow loss, a result of climate change, could get even worse by the end of the 21st century, depending on how the world reacts. Sustained action to reduce global greenhouse gas emissions could keep annual average snowfall levels steady after mid-century, but if emissions continue unabated, the study predicts that snowfall in Southern California mountains ...

Researchers solve mystery of X-ray light from black holes

2013-06-14

It is a mystery that has stymied astrophysicists for decades: how do black holes produce so many high-power X-rays? In a new study, astrophysicists from The Johns Hopkins University, NASA and the Rochester Institute of Technology bridged the gap between theory and observation by demonstrating that gas spiraling toward a black hole inevitably results in X-ray emissions. The paper states that as gas spirals toward a black hole through a formation called an accretion disk, it heats up to roughly 10 million degrees Celsius. The temperature in the main body of the disk ...

Male preference for younger female mates identified as likely cause of menopause

2013-06-14

A study published in this week's PLOS Computational Biology reports that menopause is an unintended outcome of natural selection caused by the preference of males for younger female mates. While conventional thinking has held that menopause prevents older women from continuing to reproduce, the researchers, from McMaster's University, concluded that it is the lack of reproduction that has given rise to menopause. The researchers found that, over time, competition among men of all ages for younger mates has left older females with much less chance of reproducing. The pressures ...

Finasteride, medication for male pattern hair loss, may also decrease drinking

2013-06-14

Contact: Michael S. Irwig mirwig@mfa.gwu.edu 202-741-2489 The George Washington University Contact: Chuck Zorumski zorumskc@psychiatry.wustl.edu 314-286-1700 Washington University School of Medicine Alcoholism: Clinical & Experimental Research Finasteride, medication for male pattern hair loss, may also decrease drinking Finasteride is a synthetic drug for the treatment of male pattern hair loss and an enlarged prostate. Rodent research has shown that finasteride can reduce alcohol intake. A preliminary study of men with finasteride-related sexual ...

Chronic drinking + exposure to particulate matter dramatically decreases lung function

2013-06-14

Contact: Stephania A. Cormier scorm1@lsuhsc.edu 504-568-2810 Louisiana State University Health Sciences Center Contact: George Leikauf gleikauf@pitt.edu 412-383-5305 University of Pittsburgh Alcoholism: Clinical & Experimental Research Chronic drinking + exposure to particulate matter dramatically decreases lung function Alveolar macrophage (AM) function plays a critical role in protecting the lungs by removing particulates. Chronic drinking causes persistent oxidative stress in the lungs, leading to impaired AM function. A new rodent study shows that ...

Fetal alcohol spectrum disorders and autism spectrum disorder share common molecular vulnerabilities

2013-06-14

Contact: Eva E. Redei e-redei@northwestern.edu 312-908-1791 Northwestern University Feinberg School of Medicine Contact: R. Thomas Zoeller tzoeller@bio.umass.edu 413-545-2088 University of Massachusetts Amherst Alcoholism: Clinical & Experimental Research Fetal alcohol spectrum disorders and autism spectrum disorder share common molecular vulnerabilities Both Fetal Alcohol Spectrum Disorders and Autism Spectrum Disorder are neurodevelopmental in origin. A new rodent study has found that these disorders share common molecular vulnerabilities. Findings ...

LAST 30 PRESS RELEASES:

New research delves into strengthening radiology education during a time of workforce shortages and financial constraints

The ideal scent detection dog is confident, persistent and resilient, without insecurities or neuroticism, according to a study featuring Dutch police dog handlers

Elusive beaked whales off the Louisiana coast may sometimes be diving right to the seafloor, finds new 3D acoustic technology which accurately pinpoints their locations using their echolocation clicks

The vulnerable Amazonian manatee is most often found where human activity is low, with a new eDNA-based method most commonly detecting the freshwater mammal in the remote western Amazon