Team:HIT-Harbin/project/application

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<p>&nbsp;&nbsp;&nbsp;&nbsp;The detecting system is constructed to detect the existence of Staphylococcus aureus，which is based on the global regulator of virulence, agr quorum sensing system of S.aureus that modulates the expression of virulence factors in response to autoinducing peptides (AIPs)[1]. The detecting system we constructed is mainly composed of agrA and agrC. </p>
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<p>&nbsp;&nbsp;&nbsp;&nbsp;In the pathogenic species Staphylococcus aureus, the extracellular signal of the quorum sensing system is a thiolactone-containing cyclic peptides pheromone (AIP), whose sequence varies among the different staphylococcus strains. The polymorphism in the amino acid sequence of the AIP and of its corresponding receptor (AgrC) divides S.aureus strains into four major groups. The AIPs belonging to different groups are usually mutually inhibitory[</p>
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<a>1.From medical aspect. </a>
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<p>&nbsp;&nbsp;&nbsp;&nbsp;AgrC is a transmembrane protein, which is the sensor molecule of a typical two-component signal system in S.aureus. AgrC possesses several key amino acid motifs typical of histidine protein kinase sensor. The AgrC sensor kinase can specifically binds to corresponding AIP, which secreted only from specific S.aureus, and the composite of AgrC and AIP then leads to phosphorylation of AgrA. AgrA in its phosphorylated sate activates transcription from both P2 and P3, leading to the production of GFP and 3OC6HSL. Thus we can detect the presence of S.aureus expediently by observing the expression of GFP. The figure shows the mechanism of our detecting system in E.coli.</p>
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<p>&nbsp;&nbsp;&nbsp;&nbsp;There is a trouble that the agr system belongs to S.aureus, but we hope this system works in E.coli, but . Therfore, we analyze the topology structure of AgrC and AgrA. Staphylococcus aureus AgrA, the transcriptional component of a quorum sensing system and global regulator of virulence that up-regulates secreted virulence factors and down-regulates cell wall-associated proteins, can bind in both the P2 and P3 promoter regions of the agr locus. The structure of AgrA, described by an online software PDB (Protein Data Bank), has ten β strands arranged into three antiparallel β sheets and a small α helix. The sheets are arranged roughly parallel to each other in an elongated β-β-β sandwich. A hydrophobic five-stranded β sheet (sheet 2: β3-β7) is at the center of the domain with two smaller amphipathic β sheets (sheet 1: β1-β2 and sheet 3: β8-β10) positioned on either side.</p>
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The lysostaphin expressed by the engineered E.coli will effectively avoid …. Despite the use of antibiotics, the morbidity and mortality associated with staphylococcal infections remain high and have been complicated by the emergence of strains resistant to all antibiotics in clinical use.   </p> </div>                               
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  <p>&nbsp;&nbsp;&nbsp;&nbsp;Lysostaphin is a Zn2+ metalloproteinase initially isolated from S.simulan culture with favorable activity against staphylococci in vitro and in vivo. The enzyme is currently evaluated as a potential antibacterial therapeutic for the pathogen infections. The study progresses of lysostaphin in pharmacodynamics, pharmacokinetics and clinical therapeutics attract more and more attention. The potential clinical indications are explored. </p>
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  <p>&nbsp;&nbsp;&nbsp;&nbsp;For example, S.aureus is the important pathogenic bacteria of human's vulnerable parts such as eyes, which can cause the corneal or intraocular aureus infection easily. Generally, timely we use ophthalmic with antibiotics is an effective way of controlling eye infections, but there is a problem that its resistance to antibiotics  become more and more intense. Reasearchers find that lysostaphin is effective in  treating methicillin- resistant Staphylococcus aureus endophthalmitis in the rabbit.</p>
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<p>&nbsp;&nbsp;&nbsp;&nbsp; 2.In detecting aspect. We can have a simple and fast detection of staphylococcus aureus in food or water to check whether it is polluted in our daily life. If we doubt that something has been polluted by S.aureus, we can make it into solution sample, then put our engineered E.coli into it. After a while, we can just observe the change of the color of that sample to judge the result.</p>
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  <p>&nbsp;&nbsp;&nbsp;&nbsp;For example, many villagers around your house reflect that they get diarrhea after drinking water from a well. Given that you are an agrotechnician, you can have a fast detection to identify whether it is S.aureus that causes the trouble.</p>
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  <p>&nbsp;&nbsp;&nbsp;&nbsp;3.For wastewater treatment aspect. The consortium biofilm system make these engineered E.coli embrace each other into a group, which enhance the adaptability and stability in water environment. In 2010, PKU iGEM team constructed a new engineered E.coli for detecting and absorbing heavy metal. If the sewage is polluted so badly，the engineered bacteria would be hard to survive long. If we use our biofilm formation device to reform the engineering bacteria, its adaptability in the heavy-metal polluted water will be great enhanced.</p>
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<img  src="https://static.igem.org/mediawiki/2012/0/09/Op.jpg">
<img  src="https://static.igem.org/mediawiki/2012/0/09/Op.jpg">
<font size="2"><p>Fig 2. Structure of the Staphylococcus aureus AgrA bounding to DNA<p><font>
<font size="2"><p>Fig 2. Structure of the Staphylococcus aureus AgrA bounding to DNA<p><font>

Revision as of 06:47, 24 September 2012

HIT-Harbin

Application
1.From medical aspect.

     The lysostaphin expressed by the engineered E.coli will effectively avoid …. Despite the use of antibiotics, the morbidity and mortality associated with staphylococcal infections remain high and have been complicated by the emergence of strains resistant to all antibiotics in clinical use.

    Lysostaphin is a Zn2+ metalloproteinase initially isolated from S.simulan culture with favorable activity against staphylococci in vitro and in vivo. The enzyme is currently evaluated as a potential antibacterial therapeutic for the pathogen infections. The study progresses of lysostaphin in pharmacodynamics, pharmacokinetics and clinical therapeutics attract more and more attention. The potential clinical indications are explored.

    For example, S.aureus is the important pathogenic bacteria of human's vulnerable parts such as eyes, which can cause the corneal or intraocular aureus infection easily. Generally, timely we use ophthalmic with antibiotics is an effective way of controlling eye infections, but there is a problem that its resistance to antibiotics become more and more intense. Reasearchers find that lysostaphin is effective in treating methicillin- resistant Staphylococcus aureus endophthalmitis in the rabbit.

     2.In detecting aspect. We can have a simple and fast detection of staphylococcus aureus in food or water to check whether it is polluted in our daily life. If we doubt that something has been polluted by S.aureus, we can make it into solution sample, then put our engineered E.coli into it. After a while, we can just observe the change of the color of that sample to judge the result.

    For example, many villagers around your house reflect that they get diarrhea after drinking water from a well. Given that you are an agrotechnician, you can have a fast detection to identify whether it is S.aureus that causes the trouble.

    3.For wastewater treatment aspect. The consortium biofilm system make these engineered E.coli embrace each other into a group, which enhance the adaptability and stability in water environment. In 2010, PKU iGEM team constructed a new engineered E.coli for detecting and absorbing heavy metal. If the sewage is polluted so badly，the engineered bacteria would be hard to survive long. If we use our biofilm formation device to reform the engineering bacteria, its adaptability in the heavy-metal polluted water will be great enhanced.

Fig 2. Structure of the Staphylococcus aureus AgrA bounding to DNA

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