Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tuberculosis: Diagnosis Will Be More Precise

11.11.2005


A diagnostic approach will allow to quickly and precisely identify the enemy - tuberculosis culture pathogene, the approach being based on the so-called subtraction hybridization. How it can help to identify ‘personality’ of a dangerous bacterium was discussed by researchers from Moscow with their colleagues at the II International Conference “Molecular Medicine and Biosafety” in late October this year.



For smatterers the notion of tuberculosis – is necessary and sufficient for definition of the disease and its pathogene, tubercle bacillus or, in other words, Koch’s bacillus, and has long ago lost romantic veil of Chekhov’s and Dostoyevsky’s hectic heroines. However, specialists know well that considerable genetic variability is typical of the Mycobacterium tuberculosis bacteria population. Simply speaking, these pathogenes may be very different. On the one hand, according to the force of influence on human beings: some pathogens are more, figuratively speaking, ‘wicked’ (virulent), others – are less wicked. It is necessary to know where the difference lies – what changes in the microorganism’s genome cause changes in its properties, including changes in its virulence.

Furthermore, tuberculosis pathogens, like cockroaches, are able to adapt themselves to the circumstances. If they are exterminated by people, part of them dies, but the remaining ones produce posterity resistant to the applied poison. In case of tuberculosis, this is becomes apparent in occurrence of cultures resistant to this or that kind of drugs. Therefore, to treat for sure physicians use several drug substances at once – they fight, so to say, through extended front. On top of the fact that the patient gets high doses of ‘redundant’ drugs, which are far from innocuous for a patient, as a result of such mass attack there appear cultures with multiple drug resistance, and this is a real headache for those who is trying to cure the disease.


To recognize what particular culture caused a certain patient’s disease, to study properties of this culture and, finally, to choose the most efficient and safe drug will be possible with the help of the method being developed under the guidance of Academician Evgeni Sverdlov by specialists of the Shemyakin and Ovchinnikov Institute of Bio-organic Chemistry (Russian Academy of Sciences) and their colleagues from the State Research Center for Applied Microbiology (Obolensk). Being concerned by tuberculosis attack on Russia and worldwide, the International Science and Technology Center, Ministry of Industry, Science and Technology, Russian Academy of Sciences (in the framework of the “Physicochemical Biology” program) and the Foundation of the President of the Russian Federation sponsored the researchers’ effort.

“The subtraction hybridization method is rather difficult for explanation, says Nikolai Gvozdevsky, one of the participants to the project. In a general way, the concept is that DNA molecules of the known and investigated culture are ‘clipped’ into parts in a certain way at full length, these parts are marked on both sides and they are mixed in a certain ratio. Then each part is divided into two parallel nucleotide sequences (DNA, as we know from times of Watson and Crick, is a spiral consisting of two complementary, i.e. fitting to each other in a unique way, nucleotide chains), and then these two untwisted parts are allowed to join again. Thanks to some experimental techniques, the results allow to identify which DNA sections distinguish one culture from the other and to single out these sections. A vast electronic card file already available for DNA sequences of some widespread mycobacterial cultures, for its part, may help to determine which section of the genome was found as a result and which protein product this gene (DNA section) may code.

Then the researchers use the found genomic sequences (unique for certain mycobacteria) for testing a large population sampling of pathogens for presence of these particular sequences. Unknown clinical isolate of M. tuberculosis may contain or not contain such a genetic marker in its genome composition. To answer the question “yes or no” allows another method called the PCR - polymerase chain reaction, perhaps one of the most widespread experimental approaches now in molecular clinical diagnostics. As a result of such analysis a set of final “yes” and “no” is obtained relating to all genes found in the course of subtraction hybridization, it allows like a binary code to group mycobacterial isolates and to recognize what particular culture got into the researcher’s test-tube.”

In the course of their investigation the researchers not only studied about two hundred clinical isolates educed from samples of patients’ phlegm, but also discovered three genes in the genome of one of the cultures, which were not present in the genomes of other cultures. These genes are interesting by the fact that they are typical of the isolate which is the most virulent of all. The researchers assume that these gene specifically are responsible for unusually high malicious ‘sociability’ of this culture – its ability to interact with the host organism and correspondingly its special danger (virulence) to the host.

Sergey Komarov | alfa
Further information:
http://www.informnauka.ru

More articles from Life Sciences:

nachricht Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care

nachricht Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>