11:35am Monday 25 September 2017

The cholera bacterium’s interplay with water

The cholera bacterium (Vibrio cholerae) is common in waters all over the world, particularly in mouths of water and along coasts. There it has to stress factors such as varying salt content and pH value, ultraviolet radiation, limited supply of nutrients, temperature changes and attacks from other organisms. It is reasonable to assume that some of the properties of the bacterium that causes illness for humans was originally developed to resist environment-related factors. Knowledge not only on the bacterium’s interplay with the human body, but also on that with its natural environment, is therefore necessary.

With the roundworm Caenorhabditis elegans as host for the cholera bacterium, the dissertation shows that the enzyme PrtV is neccessary to kill the worm and is also important for the bacterium’s resistance to other natural enemies, e.g. unicellular organisms (ciliates and flagellates). Experiments with PrtV show that the enzyme can break down essential elements for the coagulation of blood, which indicates that the enzyme can disrupt the healing of wounds. Little blisters in the membrane that hives off the surface of the bacterium, has shown to contain many pathogenic factors. The dissertation shows that PrtV could tie to the membrane blisters from the cholera bacterium, but only if components on the surface of the bacteria is manipulated.

Variations of the bacterium without the intestinal poison that cause the lethal cholera, can instead lead to other illnesses, e.g. ear infections, and have lately been in the attention for causing severe wound infections. It is still unknown what factors of the cholera bacterium that cause this condition. In the dissertation, seven strains of cholera are analysed isolated from patients and two watercourses to try to understand their pathogenic properties. It turned out that the same strains that could kill C. elegans were also very resistant to the blood’s defence towards invading microorganisms.

For further information, please contact:
Barbro Lindmark, Department of Molecular Biology
Phone. +46 (0)90-785 67 34
Mobile: +46 (0)70-697 88 97
E-mail: barbro.lindmark@molbiol.umu.se

On Friday 22 January Barbro Lindmark, Department of Molecular Biology, Umeå University, will defend her dissertation with the title “Modulators of Vibrio cholerae predator interaction and virulence (Modulerande faktorer för predatorinteraktioner och virulens hos Vibrio cholerae).” 
The dissertation will take place at 1:00 pm at Major Groove, Department of Molecular Biology. The faculty opponent is Prof. Kristian Riesbeck, Lund Univeristy, Malmö.

Read the abstract and/or full dissertation at:
http://umu.diva-portal.org/smash/record.jsf?pid=diva2:281137

Author: Hans Fällman


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