Team:Goettingen/Project

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<h1>The beast and its Achilles heel:<br / >
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        A novel target to fight multi-resistant pathogenic bacteria </h1>
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        <h2>The lack of novel antibiotics: the problem that we address </h2>
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        <p>The discovery of penicillin by Alexander Fleming in 1928 and the broad application of antibiotics marked a major victory of mankind in the  battle against infectious diseases. </p>
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<p> However, shortly after the beginning of industrial  penicillin  production in 1942 some human  pathogens  already acquired resistance against penicillin and related antibiotics. </p>
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<p>Moreover, the frequent use of antibiotics in the past and the rapid adaptation of bacteria to  these compounds  led to the development  of many multi-resistant pathogens.  </p>
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<p>Some of the pathogenic  bacteria  are even resistant  against most commercially available antibiotics.  Therefore, both the discovery and the development of new antibacterial substances  are extremely important to fight these threats of human health. Unfortunately, the pipeline of novel compounds with antibiotic activity  and appropriate pharmaceutical properties is  empty. This makes the challenge of finding  new compounds even more urgent!</p>
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<p> The first step in designing efficient novel antibacterial  compounds is the identification  of a suitable target. Very recently, a potentially interesting  target has been identified. The emerging signaling molecule cyclic dinucleotide c-di-AMP is essential in the Gram-positive model organism  B. subtilis  and in closely related pathogenic bacteria  such as Listeria monocytogenes, Streptococcus pneumoniae, and Staphylococcus aureus. </p>
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<p> These bacteria cause serious diseases and are often multi-resistant. c-di-AMP is needed for  the control  of  vital cellular processes in these pathogens because both: lack and accumulation of c-di-AMP, strongly inhibit growth of the bacteria. </p>
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<p> Therefore, any substance that disturbs  the homeostasis of the important signaling molecule c-di-AMP and the interaction with its  target is of substantial interest to fight human pathogens. The next important step in identifying  efficient antibacterial compounds, which either inhibit c-di-AMP biosynthesis or interfere  with the essential function of c-di-AMP  in the cell, is the development of a powerful screening system. </p>
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<h2>Our project: </h2>
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<img src="https://static.igem.org/mediawiki/2013/e/eb/Fig1.png" style="float:right;width:50%" />
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<p>Our project is aimed at the development of  a simple screening system, which allows the rapid identification and characterization of substances that disturb c-di-AMP homeostasis in pathogenic bacteria. </p>
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<p> The principle of how such a screening  system could look like is illustrated in Figure 1.  The screening system will be established in the  non-pathogenic bacterium E. coli. </p>
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<p> First, we want to construct a promoter-reporter gene fusion which allows us to monitor  the activity of a transcription factor that only binds to a specific DNA sequence (operator) in the presence of c-di-AMP. The operator sequence will be placed between a constitutively  active promoter and a reporter gene, such as  lacZ  and  gfp  encoding the -galactosidase and  the green-fluorescent protein (GFP), respectively. </p>
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<p>  The activity of either of the two proteins is very easy to detect. Then, we will evaluate  whether binding of the transcription factor and  thus inhibition of the promoter-reporter gene  fusion can be controlled by exogenous c-di-AMP. </p>
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<p> Finally, we want to express a diadenylate cyclase  from  B. subtilis  to inhibit the promoter reporter gene fusion by endogenously synthesized c-di-AMP. There are two big advantages of using E. coli as a host for the development of a screening system to  identify antibacterial compounds that interfere  with c-di-AMP homoeostasis in Gram-positive pathogenic bacteria. </p>
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<p> First, c-di-AMP is not synthesized in  E. coli. Thus, compounds that inhibit c-di-AMP synthesis will specifically inhibit growth of Gram-positive bacteria. Second, the use of a nonpathogenic E. coli strain, which is easy to cultivate will keep the costs very low.</p>
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<p>  We are confident that our screening system will facilitate the identification of novel  antibacterial substances because any change  in the activity of the c-di-AMP-dependent  promoter-reporter gene fusion, either by inhibition of c-di-AMP synthesis or by activation  of DNA-binding activity of the transcription  factor  will indicate perturbation of c-di-AMP homeostasis.  </p>
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Revision as of 15:18, 17 June 2013

The beast and its Achilles heel:

 A novel target to fight multi-resistant pathogenic bacteria