It is based on detecting short, repetitive DNA segments in the genome of bacteria. Every single bacterial strain has such characteristic repeats. "With this method we are able to identify bacterial strains as well as clarify their genetic relationships. Furthermore, we can show how new pathogenic variants develop," says Manfred Höfle, researcher at the HZI.
The results have now been published in the current issue of the scientific journal "Applied and Environmental Microbiology". The work is part of the two European Union funded projects "Healthy Water" and "AQUA-chip". Manfred Höfle is coordinator of both projects that deal with various aspects of the microbiological safety of both, drinking water and sea water.
Various bacteria that live in drinking water or sea water can cause severe human diseases. One of them are vibrios: its species Vibrio cholerae is more commonly known as the causative agent of Cholera that spread in Europe until the 20th century. Interestingly, not all Vibrio cholerae strains are pathogenic to humans. Only those strains cause severe diarrhoea known as Cholera that produce a certain bacterial toxin which attacks the intestinal wall. A less known, though also dangerous member of the genus Vibrio, is Vibrio parahaemolyticus. It is a highly contagious pathogenic germ with only a dozen ingested bacteria causing severe diarrhoea. This strain is a threat for the pacific region and reached the east coast of the United States in the 21st century. Since the end of the 1990s, Vibrio parahaemolyticus epidemics have led to thousands of cases of illness in Chile. In the future, due to ballast water or climate change, the species may also gain importance in Europe. As in the Cholera bacterium, various Vibrio parahaemolyticus strains exist with varying infectivity. Distinguishing those strains has been a challenge until now.
The newly developed method makes it now possible to characterize and distinguish hundreds of bacteria strains in a short time. The method is based on the existence of short, repetitive DNA segments in the genome of all living species. As in a tandem bike, those segments are lined up on the DNA strand, called "tandem repeats". They are characteristic for every bacterial strain. To identify a certain strain, the HZI researchers use short DNA fragments, marked with certain dyes. Each dyed DNA fragment recognizes a single tandem repeat, binding at it. As a result, the researchers receive, for example, six red fragments binding a tandem of six repetitions. Then, the researchers analyzed the tandem repeats marked with dyed fragments: Every bacteria strain differs in pattern and size of the measured tandem repeats.
"With this method, we are able to differentiate more then 120 Vibrio parahaemolyticus strains," says Manfred Höfle. This is important for infectious diseases in which it is necessary to know which strain is the causative agent. Further information are whether it is just one or more strains and where they derive from. The latter can help to prevent spreading of the disease with corresponding sanctions. "The intake of Vibrio parahaemolytics often occurs through raw clams that have filtered contaminated sea water. With this method, we are able to say from which clam species the germ originates." The new technique can also be used to characterize other bacterial pathogens and to investigate how pathogenic bacteria evolve in the environment. "Hereby, this high resolution method makes an important contribution towards a fast and precise recognition of microbial pathogens with pandemic potential."
Article: Multiple-Locus Variable-Number Tandem-Repeat Analysis for Clonal Identification of Vibrio parahaemolyticus Isolates by Using Capillary Electrophoresis. Erika Harth-Chu, Romilio T. Espejo, Richard Christen, Carlos A. Guzmán, and Manfred G. Höfle. Appl. Environ. Microbiol. 2009; 75: 4079-4088
Dr. Bastian Dornbach | EurekAlert!
Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover
First transcription atlas of all wheat genes expands prospects for research and cultivation
17.08.2018 | Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences