 |
|
Unusual carbohydrate structure in the cell walls of tuberculosis bacteria-a new point of attack for drugs?
July 27, 2004Even though we have lost much of our fear of tuberculosis in the industrialized countries, according to the WHO about 2 mio. people worldwide die each year of this infectious disease. Researchers at the University of Leeds have now discovered a carbohydrate with an unusual structure in the cell walls of Mycobacterium tuberculosis, the bacterium that causes tuberculosis. This could be a new starting point for pharmaceutical research.
The main component of the cell walls of mycobacteria is a lipoarabinomannan (LAM), a molecule consisting of a branched segment made of many sugar building blocks, which is anchored to the cell wall by a fat-like segment. The sugars involved are almost exclusively arabinose and mannose. LAM plays an important role in infection, because it helps the mycobacteria to invade macrophages, dampen the immune response, and protect the invader from oxidation. Researchers working with Achim Treumann have recently discovered that some of the mannose end groups on the outside of the molecule carry another type of sugar building block, a so called methylthiopentofuranose. This type of sugar consists of five carbon atoms (pento) and one of its usual five oxygen atoms is replaced by a sulfur atom (thio), which is also attached to a methyl group (-CH3). This discovery is astonishing because this is the first time that a methylthiosugar has been identified as a component of a polysaccharide. The sulfur atom may be responsible for the protection from oxidation provided by LAM.
However, this sugar is astonishing for another reason: it has an unexpected configuration. Like many sugars, it contains a five-membered ring made of four carbon atoms and one oxygen atom (furanose). There are eight different possibilities for the exact configuration of such a five-membered ring, because each of the four carbon atoms is attached to a further group of atoms, which could lie above or below the surface of the ring. Treumann and his co-workers took on the task of synthesizing all of the eight variations. NMR spectroscopic comparison of the eight sugars with the "original" natural form then allowed the team to identify the correct structure. In this case it has the "xylo" configuration. This is unusual, since sugars with the xylo configuration are usually only found in plants, not in bacteria.
"The discovery of this new sugar component in LAM could help in the investigation of its role in mycobacterial infections," says Treumann. "As the sugar is very unusual, enzymes that are necessary for its biosynthesis could be a good point of attack for new tuberculosis medications."
John Wiley & Sons
Tuberculosis Current Events and Tuberculosis News RSSMay hepatic granulomas be part of the histological spectrum of chronic hepatitis C?
While older large series of patients with hepatic granulomas have found sarcoidosis and tuberculosis to be the most common causes of hepatic granulomas, recent works have noted some patients with chronic hepatic C and hepatic granulomas and no other obvious associations.
Blocking the spread of antibiotic resistance in bacteria
It's as simple as A, T, G, C. Northwestern University scientists have exploited the Watson-Crick base pairing of DNA to provide a defensive tool that could be used to fight the spread of antibiotic resistance in bacteria -- one of the world's most pressing public health problems.
Researchers identify new leprosy bacterium
A new species of bacterium that causes leprosy has been identified through intensive genetic analysis of a pair of lethal infections, a research team reports in the December issue of the American Journal of Clinical Pathology.
Stopping germs from ganging up on humans
Keeping germs from cooperating can delay the evolution of drug resistance more effectively than killing germs one by one with traditional drugs such as antibiotics, according to new research from The University of Arizona in Tucson.
First trachea transplant without immunosuppression
After 4 years of going from consultation to consultation, Claudia Castillo finally found a solution to her respiratory problems. The young Colombian woman suffered from a cough that took a long time to be diagnosed as tuberculosis.
Proteomics Study Yields Clues As To How Tuberculosis Might Be Thwarting The Immune System
A link between the immune system and the self-cleaning system by which biological cells rid themselves of obsolete or toxic parts may one day yield new weapons in the fight against tuberculosis and other deadly infectious diseases.
XDR-TB: Deadlier and more mysterious than ever
New research has found that XDR-TB is increasingly common and more deadly than previously known. Extensively drug-resistant tuberculosis (XDR-TB) is a growing public health threat that is only just beginning to be understood by medical and public health officials.
Tibotec presents interim findings for TMC435, an investigational genotype 1 hepatitis C treatment
New clinical data show antiviral activity of TMC435, an investigational protease inhibitor (PI) being developed by Tibotec BVBA for the treatment of chronic hepatitis C virus (HCV) infection.
Parasites that live inside cells use loophole to thwart immune system
St. Jude Children's Research Hospital scientists have discovered a mechanism by which intracellular pathogens can shut down one of the body's key chemical weapons against them: nitric oxide.
Persistent bacterial infection exploits killing machinery of immune cells
A new study reveals an important and newly discovered pathway used by disease-causing bacteria to evade the host immune system and survive and grow within the very cells meant to destroy them. This discovery may lead to new treatments and vaccines for tuberculosis (TB) and certain other chronic bacterial and parasitic infections.
More Tuberculosis Current Events and Tuberculosis News Articles
 | Tuberculosis and the Politics of Exclusion: A History of Public Health and Migration to Los Angeles (Critical Issues in Health and Medicine) by Emily K. Abel Though notorious for its polluted air today, the city of Los Angeles once touted itself as a health resort. After the arrival of the transcontinental railroad in 1876, publicists launched a campaign to portray the city as the promised land, circulating countless stories of miraculous cures for the sick and debilitated. As more and more migrants poured in, however, a gap emerged between... |
 | The Forgotten Plague: How the Battle Against Tuberculosis Was Won - And Lost by Frank Ryan Tuberculosis has claimed more than a billion lives worldwide. In this acclaimed book, Dr. Frank Ryan tells the remarkable story of the dedicated doctors, chemists, and bacteriologists who halted the course of this ferocious disease--until the "old enemy" found in AIDS a deadly ally to form a drug-resistant synergy. 8 pages of... |
| Clinician's Guide to Tuberculosis (Clinician's Guide to Tuberculosis (Iseman)) by Michael D. Iseman Univ. of Colorado, Denver. Clinical synopsis providing essential information for those unfamiliar with the disease. Addresses the problem of managing HIV-positive patients and drug-resistant strains. Discusses, basic science, epidemiology, transmission, vaccination, and prevention. Includes tables, references, and illustrations. Softcover. DNLM:... | |
 | The Bioarchaeology of Tuberculosis: A Global View on a Reemerging Disease by CHARLOTTE ROBERTS, JANE BUIKSTRA Though apparently in decline during the first half of the 20th century, tuberculosis has reawakened in both developed and developing countries, particularly among susceptible populations with immunodeficiency disorders.... |
 | Handbook of Tuberculosis Tuberculosis (TB), a deadly airborne disease caused by the bacterium Mycobacterium tuberculosis, takes the lives of almost 2 million people each year and is considered to be the most common infectious disease in the world. However, thanks to the efforts of researchers such as the volumes’ lead editor, Dr. Stefan H. E. Kaufmann, there have been several recent advances in fighting the disease. ... |
 | Clinical Tuberculosis (A Hodder Arnold Publication) by Peter D Davies, Peeter Barnes, Stephen B Gordon Clinical Tuberculosis remains an indispensable resource for respiratory physicians, infectious disease specialists, public health workers and other individuals involved in the management and control of tuberculosis worldwide. This established reference is a comprehensive accoutn of tuberculosis, providing up-to-date and authoritative information on all aspects of the disease. It gives practical... |
 | The Return of the White Plague: Global Poverty and the 'New' Tuberculosis The dramatic increase since the 1980s in the global prevalence of tuberculosis, a disease destined as recently as thirty years ago for complete eradication, is a story of medical failure. A pandemic whose geography defies simple categorization—it ranges from schools in the UK to prisons in Russia, from refugee camps in central Africa to affluent suburbs in North America—the 'new' tuberculosis... |
 | Disease and Class: Tuberculosis and the Shaping of Modern North American Society (Health and Medicine in American Society) by Georgina D., Feldberg Until a decade ago, the conquest of tuberculosis seemed one of the great triumphs of modern medicine. The resurgence of TB in the wake of AIDS has to be understood, Georgina Feldberg argues, in the context of decisions the U.S. Public Health Service made, beginning in the 1930s, to prevent TB through improved hygiene and long-term treatment with medications, rather than program of BCG vaccination... |
 | The Making of a Social Disease: Tuberculosis in Nineteenth-Century France by David S. Barnes In this first English-language study of popular and scientific responses to tuberculosis in nineteenth-century France, David Barnes provides a much-needed historical perspective on a disease that is making an alarming comeback in the United States and Europe. Barnes argues that French perceptions of the diseaseranging from the early romantic image of a consumptive woman to the... |
| Clinical Tuberculosis by John Crofton, Norman Horne, Fred Miller This is a guide to the diagnosis of all forms of tuberculosis (TB). The second edition of the text includes a rewritten and enlarged section on HIV infection in relation to TB as well as the recommendations from experts from the World Health Organization and the International Union against Tuberculosis and Lung Disease. An outline of the WHO DOTS (Directly Observed Treatment Shortcourse)... |
| © 2009 BrightSurf.com |