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| - | <img src="https://static.igem.org/mediawiki/2011/b/b1/2162309526_9869d37c77.jpg" width="70" height="70"ALIGN="LEFT"/>
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| - | <img src="https://static.igem.org/mediawiki/2011/b/bc/Green_Lantern_Rebirth_1_coverart_%281%29.jpg" width="70" height="70" ALIGN="RIGHT"/><br/><br/><br/>
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| - | <h2 style="text-align:center;"><font color="#008000"><b><u>GREEN LANTERN</u></b></font></h2>
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| - | <p style="float: left;">
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| - | <font face="calibri" color="#080000"> One of the challenging task was to establish the lighting setup which would power the proteorhodopsin in presence of retinal to carry its H+ pumping activity in the carbon deficient condition. On rigorous searching we came across a research paper (reference and relevant extract mentioned below) which clearly defined the wavelenght and intensity to maintain the proton motive force (pmf).<br/>
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| - | <h3><font face="arial" color="#980000 "><b><u>Source</u></b></font></h3>
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| - | <b>Light-powering Escherichia coli with proteorhodopsin Jessica M. Walter, Derek Greenfield, Carlos Bustamante, and Jan Liphardt . Contributed by Carlos Bustamante, December 13, 2006 </b><br/><br/>
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| - | Prior to this paper the role of light in powering cells containing proteorhodopsin and participation in ocean energy fluxes remained largely unclear. This paper makes an attempt to show that when cellular respiration is inhibited by depleting oxygen or by the respiratory poison azide, Escherichia coli cells expressing PR become light-powered.
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| - | The paper clearly highlighted the following main points:-<br/>
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| - | <ol>
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| - | <li>The rotation rate was clearly stimulated even at the lowest light intensity studied (<font color="#00CC33"><b>5 mW/cm2</b></font>).</li>
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| - | <li>The rate increased rapidly with intensity up to <font color="#00CC33"><b>10 mW/cm2</b></font> (<font color="#00CC33"><b>15 mM</b></font> azide) or <font color="#00CC33"><b>20 mW/cm2</b></font> (<font color="#00CC33"><b>60 mM</b></font> azide) , where the effect saturated.</li>
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| - | <li>At <font color="#00CC33"><b>50 mW/cm2</b></font>, there was no detectable benefit of increased illumination. <b>(fig.2)</b></li>
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| - | <li>The maximum potential PR can generate by using the free energy from photon absorption (Vpr) is similar to the potential generated by E. Coli respiration. Only when the pmf falls below the maximum potential (Vpr) during respiratory stress does PR begin to pump, and the proton flux through PR increases as the pmf falls. PR is able to maintain E. Coli cellular pmf near this maximum potential (<font color="#00CC33"><b>Vpr = -0.2V</b></font>) with sufficiently bright illumination ( <font color="#00CC33"><b>60mW/cm2</b></font>).</li>
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| - | </ol>
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| - | <h3><font face="arial" color="#980000 "><b><u>Instrumentation</u></b></font></h3>
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| - | Power density values for <font color="#00CC33"><b>green light</b></font> refer to the power density passed by a D540/25ϫ filter originating at a 175 W Xenon bulb .The sample chamber was periodically illuminated with bright green light (160mW/cm2) coinciding with the maximum of PR’s absorption spectrum, 525 nm. At 525 nm the sample was observed to show maximum absorption (fig.1).<br/>
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| - | Based on the above fact we decided to use green LED of dominant wavelenght of 525 nm.<br/>
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| - | <h3><font face="arial" color="#980000 "><b><u>Diagrams</u></b></font></h3>
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| - | <img src="https://static.igem.org/mediawiki/2011/8/87/H11.png" width="340" height="250"/>
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| - | <img src="https://static.igem.org/mediawiki/2011/4/4f/H12.png" width="340" height="250"/>
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| - | <img src="https://static.igem.org/mediawiki/2011/9/9f/H13.png" width="340" height="250"/>
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| - | <img src="https://static.igem.org/mediawiki/2011/c/cf/H14.png" width="340" height="250"/><br/>
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| - | <font size=2><u><b>fig(1)</b> & <b>fig(2)</b> Copyright@Light-powering Escherichia coli with proteorhodopsin Jessica M. Walter, Derek Greenfield, Carlos Bustamante, and Jan Liphardt. Contributed by Carlos Bustamante, December 13, 2006 </u></font><br/>
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| - | <h3><font face="arial" color="#980000 "><b><u>Specifications</u></b></font></h3>
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| - | <ol>
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| - | <li><font color="#00CC33"><b>LM78M05</b></font> – 3 terminal positive voltage regulator</li>
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| - | <li>LED of wavelength -<font color="#00CC33"><b>525 nm</b></font>( colour- parrot green)</li>
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| - | <li><font color="#00CC33"><b>9 V</b></font> battery</li>
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| - | <li>100 ohms/51 ohms/ 33 ohms/ 18 ohms resistor</li>
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| - | </ol>
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| - | <h3><font face="arial" color="#980000 "><b><u>LED:</u></b></font></h3>
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| - | <p>OVLFx3C7 Series (green): <font color="#00CC33"><b>OVLFG3C7</b></font><b>(fig.3)</b><br/></p>
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| - | <ol>
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| - | <li>Characteristics<br/>
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| - | <ul>
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| - | <li>High brightness with well-defined spatial radiation patterns</li>
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| - | <li>UV -resistant epoxy lens</li>
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| - | <li>Round Through-Hole LED Lamp(5 mm)</li>
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| - | </ul>
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| - | <li>Material - <font color="#00CC33"><b>InGaN</b></font></li>
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| - | <li>Typical Intensity - <font color="#00CC33"><b>5200 mcd (millicandela)</b></font></li>
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| - | <li>Lens colour - <font color="#00CC33"><b>water clear</b></font></li>
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| - | <li>Operating Voltage - <font color="#00CC33"><b>(-40 to 85) degree C</b></font></li>
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| - | <li>Continous forward current - <font color="#00CC33"><b>20mA</b></font></li>
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| - | <li>Peak Wavelength - <font color="#00CC33"><b>521 nm</b></font></li>
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| - | <li>Dominant Wavelength - <font color="#00CC33"><b>525 nm</b></font></li>
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| - | <li>Spectra Half-Width - <font color="#00CC33"><b>25 nm</b></font></li><br/>
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| - | <h3><font face="calibri" color="#980000 "><b><u>Circuit Diagram of the Setup</u></b></font></h3><br/>
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| - | <img src="https://static.igem.org/mediawiki/2011/1/11/H15.png" width="300" height="200"/>
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| - | <h3><font face="calibri" color="#980000 "><b><u>Observation</u></b></font></h3><br/>
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| - | <table border="1">
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| - | <tr>
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| - | <td></td>
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| - | <td><b>Reading 1</b></td>
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| - | <td><b>Reading 2</b></td>
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| - | <td><b>Reading 3</b></td>
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| - | <td><b>Reading 4</b></td>
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| - | </tr>
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| - | <tr>
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| - | <td><b>Vss (V)</b></td>
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| - | <td> 5.56</td>
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| - | <td> 5.56</td>
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| - | <td> 5.56</td>
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| - | <td> 5.56</td>
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| - | </tr>
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| - | <tr>
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| - | <td><b>Vr(V)</b></td>
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| - | <td> 0.5</td>
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| - | <td> 1.0</td>
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| - | <td> 0.33</td>
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| - | <td> 0.66</td>
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| - | </tr>
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| - | <tr>
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| - | <td><b>V led(V)</b></td>
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| - | <td> 5.06</td>
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| - | <td> 4.56</td>
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| - | <td> 5.23</td>
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| - | <td> 4.9</td>
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| - | </tr>
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| - | <tr>
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| - | <td><b>I led(mA)</b></td>
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| - | <td> 29.7</td>
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| - | <td> 26.8</td>
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| - | <td> 30.7</td>
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| - | <td> 28.8</td>
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| - | </tr>
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| - | </table><br/>
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| - | <h3><font face="calibri" color="#980000 "><b><u>Calculation</u></b></font></h3><br/>
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| - | <ul>
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| - | <li>LED equivalent efficiency - <font color="#00CC33"><b>40 lumen/W</b></font></li>
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| - | <li>Luminous Intensity - <font color="#00CC33"><b>5.2 cd = 65.52 lumens</b></font></li>
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| - | <li>Power given (excluding heat) by 1 LED - <font color="#00CC33"><b>1.638 W</b></font></li>
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| - | <li>Power by 140 LEDs -<font color="#00CC33"><b>229.32 W</b></font></li>
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| - | <li>Luminous Intensity -<font color="#00CC33"><b>81.105359 mW/cm2</b></font></li>
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| - | <li>Internal Resistance of LED - <font color="#00CC33"><b>3.4 V/ 20 mA = 170 ohms</b></font></li>
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| - | </ul><br/>
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| - | Assuming average current across the LED to be 30 mA. This gives an Luminous Efficiency to be 135% <b>(fig.4)</b>.
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| - | So the luminous Intensity of the entire lighting setup = <font color="#00CC33"><b>109.4922 mW/cm2</b></font>
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| - | The 140 LEDs were fixed in 3 breadboards . The luminous intensity calculated above is a cumulative effect of all The LED's. So depending upon how many breadboards we use, we can choose to establish a luminous intensity of <font color="#00CC33"><b>37 mW/cm2, 74 mW/cm2</b></font> and <font color="#00CC33"><b>109.4922 mW/cm2</b>.</font>
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| - | The distance of the lighting source from the flask containing Proteorhodopsin and Retinal was strictly maintained at <font color="#00CC33"><b>15cm</b></font>.<br/>
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| - | </font>
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| - | </p></div>
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