Difference between revisions of "Team:CityU HK/Results"

Latest revision as of 20:10, 18 September 2015

Results - iGEM2015 wiki

Characterization of the lactose-inducible promoter (BBa_K1695053)

The GFP reporter biobrick (BBa_K1695053) was constructed by linking the above lacI-regulated promoter (BBa_K1695000) to GFP (BBa_I13504) (Figure 1). The response of this GFP reporter construct to IPTG induction was then measured based on the GFP fluorescence signal (excitation wavelength: 485nm; emission wavelength: 520 nm). GFP fluorescence signal from cells carrying the PL8-UV5-GFP construct (BBa_K1695053) was monitored over a 4.5-hour time course under a range of IPTG concentrations ranging from 0.01 – 10 mM. Normalization of GFP fluorescence was performed based on the A600 values of the culture.

Figure 1. Construct of the reporter biobrick, BBa_K1695053

Figure 2. Expression analysis of L8-UV5 promoter-GFP biobrick (BBa_K1695053). (A) Activation of GFP expression in the L8-UV5 promoter construct is dependent on IPTG concentrations below 1 mM. (B) Fluorescence response of the L8-UV5 promoter-GFP gene construct (BBa_K1695053) was measured over a 4.5-h time course under a range of IPTG concentrations (from 0.01 mM to 10 mM). Results show that induction of the L8-UV5 promoter is independent of IPTG at concentrations above 1 mM, where LacI is saturated and promoter is fully turned on.

Results in Figure 2 show that GFP expression in the L8-UV5 promoter-GFP construct is dependent on IPTG concentrations below 1 mM. At IPTG concentrations above 1 mM, expression of GFP has reached a maxima regardless of the sampling time points.

Improved/ expanded characterization of LacY-LacZ biobrick (BBa_S04055)

Figure 3. Quantitative RT-PCR analysis of lacY and lacZ expression in E. coli cells. Expression of the lacZ and lacY genes was measured in control DH5α cells (BLUE) and BBa_S04055 recombinant DH5α cells (RED). Cells were cultured overnight in LB medium + antibiotic and total RNA harvested for qRT-PCR using 16S rRNA for normalization.

A. Quantitative real-time PCR

Quantitative real-time PCR analysis showed that both lacY and lacZ mRNA transcripts are expressed at high levels in recombinant E. coli cells (harboring the BBa_S04055 biobrick) as compared to control DH5α cells (Figure 3). Expression of lacY and lacZ is 9- fold and 2-fold higher, respectively, in recombinant cells with respect to the control cells.

B. Western Blot Analysis

Western blot analysis showed that the β-galactosidase protein (LacZ) (indicated by the arrow) is expressed at a significantly higher level in recombinant E. coli cells (BBa_S04055) relative to the control (Figure 4) and is in agreement with the lacZ mRNA results described in Figure 3.

Figure 4. Western Blot analysis of β-galactosidase (LacZ) protein. Expression of the β-galactosidase protein (~ 135 kDa band) in control (Lane 1) and recombinant (BBa_S04055) (Lane2) E. coli cells.

Figure 5. Expression of β-galactosidase as measured by the ONPG assay. Control (BLUE) E. coli cells and BBa_S04055 recombinant cells (RED) at OD₆₀₀=0.3 were harvested and lysed to release intracellular β-galactosidase, which was then measured for its activity by the ONPG assay. The conversion was measured by A₄₂₀ at 15 minute interval.

C. Measurement of β-galactosidase enzyme activity using ONPG Assay

The level of β–galactosidase activity was measured in recombinant (BBa_S04055) and control E. coli cells using the ONPG colorimetric assay. The results in Figure 5 show that the concentration of the cleavage product (A₄₂₀) increased linearly within 60 minutes in the recombinant cells (BBa_S04055) while no change in absorbance was observed in control cells which indicated that the β-galactosidase enzyme activity is expressed in the recombinant cells and is in agreement with the results previously reported by the 2008 Caltech iGEM team.

Characterization of Lysis Gene Cassette Smutλ-Rλ-Rzλ (BBa_K1695038)

Upon induction with 0.2 mM, 1 mM and 5 mM of IPTG, recombinant E. coli harboring the lysis cassette Smutλ-Rλ-Rzλ (BBa_K1695038) showed a sharp drop in absorbance (A600) after 15 minutes whereas cells without IPTG induction showed continued as indicated by the steady increase in OD (Figure 6A). The results show that 0.2 mM IPTG is sufficient to initiate cell lysis after 15 minutes, and the speed of cell lysis is not increased at higher concentrations of IPTG (Figure 6B). Overall, the use of (1) OD600 measurement to determine cell growth or cell lysis (panel A) and (2) plate count (cfu; panel B) showed that the Lysis Gene Cassette is induced by IPTG and resulted in the initiation of cell lysis after 15 minutes of IPTG induction. Cells were completely lysed by 20 minutes. It would be interesting in future studies to determine if the time of cell lysis could be regulated by IPTG at concentrations below 0.2 mM.

Figure 6. Cell lysis upon induction of lysis cassette by IPTG in E. coli cells. Recombinant E. coli carrying lysis cassette Smutλ-Rλ-Rzλ (BBa_K1695038) was cultured in minimal medium (supplemented with 0.2% glucose and 0.5(0.02%) casamino acid). IPTG at various concentrations (0 mM, ·) (0.2 mM, ·), 1 mM, ·) (5 mM, ·) was added to the bacterial culture at OD600 ~ 0.6. Samples were taken at 5-min and 10-min intervals from IPTG induced and uninduced cultures for (A) OD600 measurements and (B) cell plating on LB solid medium (CFU count) to determine the percentage (%) of cell survival, respectively.

ABOUT US

We are a diverse team of CityU undergraduates, working hard to create a better world.

LOCATION

Department of Biology and Chemistry,
City University of Hong Kong
Tat Chee Avenue, Kowloon,
Hong Kong SAR

CONTACT US

Email: cityu.igem2015@gmail.com
Tel: +852 34427654

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+<div class="area"></div><nav class="main-menu">
+            <ul>
+                <li>
+                    <a  class="scroll" href="#laczy">
+                      <i class="sidebar-fa"></i>
+                        <span class="nav-text" id="first-item">
+                            LacZY plasmid
+                        </span>
+                    </a>
+                </li>
+                <li class="has-subnav">
+                    <a  class="scroll" href="#lactose">
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+                        <span class="nav-text">
+                            Lactose inducible promoter
+                        </span>
+                    </a>
+                </li>
+                <li class="has-subnav">
+                    <a class="scroll" href="#lysis">
+                      <i class="sidebar-fa"></i>
+                        <span class="nav-text">
+                            Lysis plasmid
+                        </span>
+                    </a>
+                </li>
+            </ul>
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+  <div class="wrapper">
+		<div class="banner-wrap wsite-background wsite-custom-background">
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+					<h2><span class="wsite-text wsite-headline">
+	Results
+</span></h2>
+				</div>
+			</div>
+		</div>
+		<div class="main-wrap">
+	    <div class="container">
+<div class="content-wrap"><div id='wsite-content' class='wsite-elements wsite-not-footer'>
+<div id="lactose"><div style="height: 50px; overflow: hidden; width: 100%;"></div>
+<div style="height: 30px; overflow: hidden; width: 100%;"></div></div>
+<div style="display:block;font-size:90%"></div>
+<h2  class="wsite-content-title" style="text-align:left;"><span "font-size:14.0pt;="" line-height:107%;font-family:&quot;calibri&quot;,sans-serif;mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:&quot;times="" roman&quot;;mso-bidi-theme-font:minor-bidi;="" mso-ansi-language:en-us;mso-fareast-language:zh-tw;mso-bidi-language:ar-sa"=""><font size="6">Characterization of the lactose-inducible promoter (BBa_K1695053)</font></span><br /><span style=""></span></h2>
+<div class="paragraph" style="text-align:justify;"><br /><font color="#2a2a2a"><strong style="font-size: medium;"><em><span style="line-height: 107%;">&nbsp;</span></em></strong><span style="font-size: medium; line-height: 1.5em; text-align: justify; background-color: initial;"><font size ="3.5">The GFP reporter biobrick (BBa_K1695053) was constructed by linking
+the above lacI-regulated promoter </span><span style="font-size: medium; line-height: 1.5em; text-align: justify; background-color: initial;">(BBa_K1695000)</span>
+<span style="font-size: medium; line-height: 1.5em; text-align: justify; background-color: initial;">to GFP (BBa_I13504) (Figure 1). The response of this GFP reporter
+construct to IPTG induction was then measured based on the GFP fluorescence
+signal (excitation wavelength: 485nm; emission wavelength: 520 nm). GFP
+fluorescence signal from cells carrying the PL8-UV5-GFP construct (BBa_K1695053)
+was monitored over a 4.5-hour time course under a range of IPTG concentrations
+ranging from 0.01 &ndash; 10 mM. Normalization of GFP fluorescence was performed
+based on the A</span><font size="1">600</font></font><span style="font-size: medium; line-height: 1.5em; text-align: justify; background-color: initial;"><font color="#2a2a2a"> values of the culture.</font></span><span style=""></span><br /><span style=""></span><br /><span style=""></span><span style=""></span></div>
+<div><div class="wsite-image wsite-image-border-none " style="padding-top:10px;padding-bottom:10px;margin-left:0;margin-right:0;text-align:center">
+<a>
+<img src="https://static.igem.org/mediawiki/2015/c/cb/2015CityU_HK_Result_fig1.jpeg" alt="Picture" style="width:310;max-width:60%" />
+</a>
+<div style="display:block;font-size:90%"></div>
+</div></div>
+<div class="paragraph" style="text-align:center;"><font color="#2a2a2a" size="3"><strong>Figure 1. Construct of the reporter biobrick, BBa_K1695053</strong></font><br /><span style=""></span></div>
+<div><div class="wsite-multicol"><div class="wsite-multicol-table-wrap" style="margin:0 -15px;">
+	<table class="wsite-multicol-table">
+		<tbody class="wsite-multicol-tbody">
+			<tr class="wsite-multicol-tr">
+				<td class="wsite-multicol-col" style="width:50%; padding:0 15px;">
+<div><div class="wsite-image wsite-image-border-none " style="padding-top:5px;padding-bottom:10px;margin-left:0;margin-right:0;text-align:right">
+<a>
+<img src="https://static.igem.org/mediawiki/2015/e/e9/2015CityU_HK_result_fig2a.jpeg" alt="Picture" style="width:321; max-width:80%" />
+</a>
+<div style="display:block;font-size:90%"></div>
+</div></div>
+				</td>				<td class="wsite-multicol-col" style="width:50%; padding:0 15px;">
+<div><div class="wsite-image wsite-image-border-none " style="padding-top:10px;padding-bottom:10px;margin-left:0;margin-right:0;text-align:left">
+<a>
+<img src="https://static.igem.org/mediawiki/2015/7/72/2015CityU_HK_result_fig2b.jpeg" alt="Picture" style="width:424;max-width:100%" />
+</a>
+<div style="display:block;font-size:90%"></div>
+</div></div>
+				</td>			</tr>
+		</tbody>
+	</table>
+</div></div></div>
+<div class="paragraph" style="text-align:justify;"><font size="3"><strong><span "font-size:11.0pt;="" line-height:107%;font-family:&quot;calibri&quot;,sans-serif;mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:&quot;times="" roman&quot;;mso-bidi-theme-font:minor-bidi;="" mso-ansi-language:en-us;mso-fareast-language:zh-tw;mso-bidi-language:ar-sa"=""><font color="#2a2a2a"><font size="2">Figure 2. Expression analysis of L8-UV5 promoter-GFP biobrick (BBa_K1695053). </font></span></strong><span "font-size:11.0pt;line-height:107%;font-family:&quot;calibri&quot;,sans-serif;="" mso-ascii-theme-font:minor-latin;mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:="" minor-fareast;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:&quot;times="" roman&quot;;="" mso-bidi-theme-font:minor-bidi;mso-ansi-language:en-us;mso-fareast-language:="" zh-tw;mso-bidi-language:ar-sa;mso-bidi-font-weight:bold"=""><font color="#2a2a2a">&nbsp;</font><font color="#2a2a2a"><font size="2">(A) Activation of GFP expression in the L8-UV5 promoter construct is dependent on IPTG concentrations below 1 mM. (B) Fluorescence response of the L8-UV5 promoter-GFP gene construct (BBa_K1695053) was measured over a 4.5-h time course under a range of IPTG concentrations (from 0.01 mM to 10 mM). Results show that induction of the L8-UV5 promoter is independent of IPTG at concentrations above 1 mM, where LacI is saturated and promoter is fully turned on<em>.&nbsp;</em></font></span><br /></font><br /><font size="4"><br /><span "font-size:11.0pt;line-height:="" 107%;font-family:&quot;calibri&quot;,sans-serif;mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:&quot;times="" roman&quot;;mso-bidi-theme-font:minor-bidi;="" mso-ansi-language:en-us;mso-fareast-language:zh-tw;mso-bidi-language:ar-sa"="" style=""><font color="#2a2a2a">Results in Figure 2 show that GFP expression in the L8-UV5 promoter-GFP construct is dependent on IPTG concentrations below 1 mM. At IPTG concentrations above 1 mM, expression of GFP has reached a maxima regardless of the sampling time points.</font></span></font><span "font-size:11.0pt;line-height:107%;font-family:&quot;calibri&quot;,sans-serif;="" mso-ascii-theme-font:minor-latin;mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:="" minor-fareast;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:&quot;times="" roman&quot;;="" mso-bidi-theme-font:minor-bidi;mso-ansi-language:en-us;mso-fareast-language:="" zh-tw;mso-bidi-language:ar-sa;mso-bidi-font-weight:bold"="" style=""><br /><br /><br /></span></div>
+<div id="laczy"><div style="height: 100px; overflow: hidden; width: 100%;"></div>
+<hr class="styled-hr" style="width:100%;"></hr>
+<div style="height: 30px; overflow: hidden; width: 100%;"></div></div>
+<h2 class="wsite-content-title" style="text-align:left;"><span "font-size:14.0pt;="" line-height:107%;font-family:&quot;calibri&quot;,sans-serif;mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:&quot;times="" roman&quot;;mso-bidi-theme-font:minor-bidi;="" mso-ansi-language:en-us;mso-fareast-language:zh-tw;mso-bidi-language:ar-sa"=""><font size="6">Improved/ expanded characterization of LacY-LacZ biobrick (BBa_S04055)</font></span><br /><span style=""></span></h2>
+<div><div class="wsite-multicol"><div class="wsite-multicol-table-wrap" style="margin:0 -15px;">
+	<table class="wsite-multicol-table">
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+</a>
+</div></div>
+<div class="paragraph" style="text-align:justify;"> <strong><span "font-size:11.0pt;="" line-height:107%;font-family:&quot;calibri&quot;,sans-serif;mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:&quot;times="" roman&quot;;mso-bidi-theme-font:minor-bidi;="" mso-ansi-language:en-us;mso-fareast-language:zh-tw;mso-bidi-language:ar-sa"=""><font color="#2a2a2a"><font size="2">Figure 3. Quantitative RT-PCR analysis of <em style="">lacY</em> and <em style="">lacZ</em> expression in <em style="">E. coli </em>cells.</font></font></span></strong><span "font-size:11.0pt;line-height:107%;font-family:&quot;calibri&quot;,sans-serif;="" mso-ascii-theme-font:minor-latin;mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:="" minor-fareast;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:&quot;times="" roman&quot;;="" mso-bidi-theme-font:minor-bidi;mso-ansi-language:en-us;mso-fareast-language:="" zh-tw;mso-bidi-language:ar-sa;mso-bidi-font-weight:bold"=""><font size="2"><font color="#2a2a2a">&#160;Expression of the </font><em style="color: rgb(42, 42, 42);">lacZ</em><font color="#2a2a2a"> and </font><em style="color: rgb(42, 42, 42);">lacY</em><font color="#2a2a2a"> genes was measured in control DH5&#945; cells </font><span "font-size:11.0pt;="" line-height:107%;font-family:&quot;calibri&quot;,sans-serif;mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:&quot;times="" roman&quot;;mso-bidi-theme-font:minor-bidi;="" mso-ansi-language:en-us;mso-fareast-language:zh-tw;mso-bidi-language:ar-sa"=""><strong><font color="#24678d">(BLUE)</font></strong><font color="#2a2a2a"> and BBa_S04055 recombinant </font><em style="color: rgb(42, 42, 42);">DH5&#945;</em><font color="#2a2a2a"> cells</font><font color="#da4444"><strong> (RED)</strong></font><font color="#2a2a2a">.</font></span><span "font-size:13.5pt;font-family:&quot;arial&quot;,sans-serif;color:#333333;="" mso-fareast-language:zh-hk"="" style="color: rgb(42, 42, 42);"> </span><span "font-size:11.0pt;="" line-height:107%;font-family:&quot;calibri&quot;,sans-serif;mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:&quot;times="" roman&quot;;mso-bidi-theme-font:minor-bidi;="" mso-ansi-language:en-us;mso-fareast-language:zh-tw;mso-bidi-language:ar-sa"=""><font color="#2a2a2a"><i>Cells were cultured overnight in LB medium + antibiotic and total RNA harvested for qRT-PCR using 16S rRNA for normalization.</i></font></span><br /><br /></div>
+				</td>				<td class="wsite-multicol-col" style="width:62.068965517242%; padding:0 15px;">
+<h2 class="wsite-content-title" style="text-align:left;"><strong style=""><u style=""><span "font-size:18.0pt;="" font-family:&quot;arial&quot;,sans-serif;color:#333333"="" style=""><font size="6">A. Quantitative real-time PCR</font></span></u></strong><br /><span style=""></span></h2>
+<div class="paragraph" style="text-align:justify;"><font size="3"><span "mso-bidi-font-size:13.5pt;="" font-family:&quot;arial&quot;,sans-serif;color:black;mso-themecolor:text1"="">Quantitative real-time PCR analysis showed that both lacY and lacZ mRNA transcripts are expressed at high levels in recombinant E. coli cells (harboring the BBa_S04055 biobrick) as compared to control DH5α cells (Figure 3). Expression of lacY and lacZ is 9- fold and 2-fold higher, respectively, in recombinant cells with respect to the control cells.</span></font></div>
+				</td>			</tr>
+		</tbody>
+	</table>
+</div></div></div>
+<div><div class="wsite-multicol"><div class="wsite-multicol-table-wrap" style="margin:0 -15px;">
+	<table class="wsite-multicol-table">
+		<tbody class="wsite-multicol-tbody">
+			<tr class="wsite-multicol-tr">
+				<td class="wsite-multicol-col" style="width:44.679343403567%; padding:0 15px;">
+<h2 class="wsite-content-title" style="text-align:left;"><strong style=""><u style=""><span "font-size:18.0pt;font-family:&quot;arial&quot;,sans-serif;mso-fareast-font-family:="" &#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:minor-fareast;color:#333333;mso-ansi-language:en-us;="" mso-fareast-language:zh-tw;mso-bidi-language:ar-sa"="" style=""><font size="6">B. Western Blot Analysis</font><font size="5">&nbsp;</font></span></u></strong></h2>
+<div class="paragraph" style="text-align:justify;"><font size="3">Western blot analysis showed that the β-galactosidase protein (LacZ) (indicated by the arrow) is expressed at a significantly higher level in recombinant <em style="">E. coli</em> cells (BBa_S04055) relative to the control (Figure 4) and is in agreement with the <em style="">lacZ</em> mRNA results described in Figure 3.</font></div>
+				</td>				<td class="wsite-multicol-col" style="width:47.360104007781%; padding:0 15px;">
+<div><div class="wsite-image wsite-image-border-none " style="padding-top:10px;padding-bottom:10px;margin-left:0;margin-right:0;text-align:center">
+<a>
+<img src="https://static.igem.org/mediawiki/2015/d/df/2015CityU_HK_westernblotgel.jpeg" alt="Picture" style="width:auto;max-width:100%" />
+</a>
+<div style="display:block;font-size:90%"></div>
+</div></div>
+<div class="paragraph" style="text-align:justify;"> <strong><span "font-size:11.0pt;="" line-height:107%;font-family:&quot;calibri&quot;,sans-serif;mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:&quot;times="" roman&quot;;mso-bidi-theme-font:minor-bidi;="" mso-ansi-language:en-us;mso-fareast-language:zh-tw;mso-bidi-language:ar-sa"=""><font color="#2a2a2a"><font size="2">Figure 4. Western Blot analysis of &#946;-galactosidase (LacZ) protein.</font></font></span></strong><span "font-size:11.0pt;line-height:107%;font-family:&quot;calibri&quot;,sans-serif;="" mso-ascii-theme-font:minor-latin;mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:="" minor-fareast;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:&quot;times="" roman&quot;;="" mso-bidi-theme-font:minor-bidi;mso-ansi-language:en-us;mso-fareast-language:="" zh-tw;mso-bidi-language:ar-sa;mso-bidi-font-weight:bold"=""><font size="2"><font color="#2a2a2a">&#160; Expression of the &#946;-galactosidase protein (~ 135 kDa band) in control (Lane 1) and recombinant (BBa_S04055) (Lane2) <em style=””>E. coli</em> cells. </font></font></span><br /><br /><br /></div>
+				</td>				<td class="wsite-multicol-col" style="width:7.9605525886518%; padding:0 15px;">
+<div class="wsite-spacer" style="height:50px;"></div>
+				</td>			</tr>
+		</tbody>
+	</table>
+</div></div></div>
+<div><div class="wsite-multicol"><div class="wsite-multicol-table-wrap" style="margin:0 -15px;">
+	<table class="wsite-multicol-table">
+		<tbody class="wsite-multicol-tbody">
+			<tr class="wsite-multicol-tr">
+				<td class="wsite-multicol-col" style="width:43.941109852775%; padding:0 15px;">
+<div><div class="wsite-image wsite-image-border-none " style="padding-top:10px;padding-bottom:10px;margin-left:0;margin-right:0;text-align:center">
+<a>
+<img src="https://static.igem.org/mediawiki/2015/6/64/2015CityU_HK_ONPGassay.jpeg" alt="Picture" style="width:auto;max-width:100%" />
+</a>
+<div style="display:block;font-size:90%"></div>
+</div></div>
+<div class="paragraph" style="text-align:justify;"> <strong><span "font-size:11.0pt;="" line-height:107%;font-family:&quot;calibri&quot;,sans-serif;mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:&quot;times="" roman&quot;;mso-bidi-theme-font:minor-bidi;="" mso-ansi-language:en-us;mso-fareast-language:zh-tw;mso-bidi-language:ar-sa"=""><font color="#2a2a2a"><font size="2">Figure 5. Expression of &#946;-galactosidase as measured by the ONPG assay.</font></font></span></strong><span "font-size:11.0pt;line-height:107%;font-family:&quot;calibri&quot;,sans-serif;="" mso-ascii-theme-font:minor-latin;mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:="" minor-fareast;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:&quot;times="" roman&quot;;="" mso-bidi-theme-font:minor-bidi;mso-ansi-language:en-us;mso-fareast-language:="" zh-tw;mso-bidi-language:ar-sa;mso-bidi-font-weight:bold"=""><font size="2"><font color="#2a2a2a">&#160; Control </font><strong><font color="#24678d">(BLUE)</font></strong><font color="#2a2a2a"> <em style=””>E. coli</em> cells and  BBa_S04055 recombinant cells </font><strong><font color="#da4444">(RED)</font></strong><font color="#2a2a2a"> at OD<sub>600</sub>=0.3 were harvested and lysed to release intracellular &#946;-galactosidase, which was then measured for its activity by the ONPG assay. The conversion was measured by A<sub>420</sub> at 15 minute interval.</font></font></font></span><br /><br /></div>
+				</td>				<td class="wsite-multicol-col" style="width:56.058890147225%; padding:0 15px;">
+<h2 class="wsite-content-title" style="text-align:left;"><strong style=""><u style=""><span "font-size:18.0pt;font-family:&quot;arial&quot;,sans-serif;color:#333333;="" mso-fareast-language:zh-hk"="" style=""><font size="6">C. Measurement of β-galactosidase enzyme activity using ONPG Assay</font></span></u></strong><br /><span style=""></span></h2>
+<div class="paragraph"><font size="3"><span "mso-bidi-font-size:13.5pt;font-family:&quot;arial&quot;,sans-serif;="" color:black;mso-themecolor:text1;mso-fareast-language:zh-hk"="">The level of &beta;–galactosidase activity was measured in recombinant (BBa_S04055) and control E. coli cells using the ONPG colorimetric assay. The results in Figure 5 show that the concentration of the cleavage product (A<sub>420</sub>) increased linearly within 60 minutes in the recombinant cells (BBa_S04055) while no change in absorbance was observed in control cells which indicated that the &beta;-galactosidase enzyme activity is expressed in the recombinant cells and is in agreement with the results previously reported by the 2008 Caltech iGEM team.</span><br /></font><span style=""></span><br /><span style=""></span></div>
+				</td>			</tr>
+		</tbody>
+	</table>
+</div></div></div></div>
+<div id="lysis"><div style="height: 100px; overflow: hidden; width: 100%;"></div>
+<hr class="styled-hr" style="width:100%;"></hr>
+<div style="height: 30px; overflow: hidden; width: 100%;"></div></div>
+<h2 class="wsite-content-title" style="text-align:left;"><span "font-size:14.0pt;="" line-height:107%;font-family:&quot;calibri&quot;,sans-serif;mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:&quot;times="" roman&quot;;mso-bidi-theme-font:minor-bidi;="" mso-ansi-language:en-us;mso-fareast-language:zh-tw;mso-bidi-language:ar-sa"=""><font size="6">Characterization of Lysis Gene Cassette</span><span "font-size:12.0pt;line-height:107%;font-family:&quot;arial&quot;,sans-serif;="" color:black;mso-themecolor:text1;mso-font-kerning:12.0pt"="" style=""> </span><span "font-size:14.0pt;line-height:107%;font-family:&quot;arial&quot;,sans-serif;="" color:black;mso-themecolor:text1;mso-font-kerning:12.0pt"="" style="">S<span style="">mut</span><span style="">&lambda;</span>-R<span style="">&lambda;</span>-R<span style="">z</span><span style="">&lambda;</span></span><span style="">&nbsp;(BBa_K1695038)</font></span><br /><span style=""></span></h2>
+<div class="paragraph" ><span "font-size:11.0pt;line-height:="" 107%;font-family:&quot;arial&quot;,sans-serif;mso-fareast-font-family:&#26032;&#32048;&#26126;&#39636;;mso-fareast-theme-font:="" minor-fareast;color:black;mso-themecolor:text1;mso-font-kerning:12.0pt;="" mso-ansi-language:en-us;mso-fareast-language:zh-tw;mso-bidi-language:ar-sa"="" style=""><font color="#2a2a2a"><span id="selectionBoundary_1442551834478_6921464148908854" class="rangySelectionBoundary" style="line-height: 0; display: none;">&#65279;</span><font size="3.5">Upon induction with 0.2 mM, 1 mM and 5 mM of IPTG, recombinant </font><em style="font-size: medium;">E. coli</em><font size="3.5"> harboring the lysis cassette S</font><span "position:="" relative;top:3.0pt;mso-text-raise:-3.0pt"=""><font size="2">mut</font></span><font size="3.5">&lambda;-R&lambda;-Rz&lambda; (BBa_K1695038) showed a sharp drop in absorbance (A</font><font size="1">600</font><font size="3.5">) after 15 minutes whereas cells without IPTG induction showed continued as indicated by the steady increase in OD (Figure 6A). The results show that 0.2 mM IPTG is sufficient to initiate cell lysis after 15 minutes, and the speed of cell lysis is not increased at higher concentrations of IPTG (Figure 6B). Overall, the use of (1) OD</font><font size="1">600 </font><font size="3.5">measurement to determine cell growth or cell lysis (panel A) and (2) plate count (cfu; panel B) showed that the Lysis Gene Cassette is induced by IPTG and resulted in the initiation of cell lysis after 15 minutes of IPTG induction. Cells were completely lysed by 20 minutes. It would be interesting in future studies to determine if the time of cell lysis could be regulated by IPTG at concentrations below 0.2 mM.</font><span id="selectionBoundary_1442551834478_7756834849715233" class="rangySelectionBoundary" style="line-height: 0; display: none;">&#65279;</span></font></span></div>
+<div><div class="wsite-multicol"><div class="wsite-multicol-table-wrap" style="margin:0 -15px;">
+	<table class="wsite-multicol-table">
+		<tbody class="wsite-multicol-tbody">
+			<tr class="wsite-multicol-tr">
+				<td class="wsite-multicol-col" style="width:50%; padding:0 15px;">
+<div><div class="wsite-image wsite-image-border-none " style="padding-top:10px;padding-bottom:10px;margin-left:0;margin-right:0;text-align:right">
+<a>
+<img src="https://static.igem.org/mediawiki/2015/7/7d/2015CityU_HK_Result_Fig6a.jpeg" alt="Picture" style="width:311;max-width:100%" />
+</a>
+<div style="display:block;font-size:90%"></div>
+</div></div>
+				</td>				<td class="wsite-multicol-col" style="width:50%; padding:0 15px;">
+<div><div class="wsite-image wsite-image-border-none " style="padding-top:10px;padding-bottom:10px;margin-left:0;margin-right:0;text-align:left">
+<a>
+<img src="https://static.igem.org/mediawiki/2015/e/e7/2015CityU_HK_result_fig6b.jpeg" alt="Picture" style="width:316;max-width:100%" />
+</a>
+</div></div>
+				</td>			</tr>
+		</tbody>
+	</table>
+</div></div></div>
+<div class="paragraph" style="text-align:justify;"><span "font-family:="" &quot;arial&quot;,sans-serif;color:black;mso-themecolor:text1;mso-font-kerning:12.0pt"=""></span><font size="4"><span "font-family:="" &quot;arial&quot;,sans-serif;color:black;mso-themecolor:text1;mso-font-kerning:12.0pt"="" style="color: rgb(42, 42, 42);"><span "font-family:&quot;arial&quot;,sans-serif;="" color:black;mso-themecolor:text1;mso-font-kerning:12.0pt"=""><font size ="2"><strong>Figure 6. Cell lysis upon induction of lysis cassette by IPTG in&nbsp;<em>E. coli</em>&nbsp;cells.&nbsp;</strong></span>Recombinant<em> E. coli</em> carrying lysis cassette Smut&lambda;-R&lambda;-Rz&lambda;&nbsp;(BBa_K1695038) was cultured in minimal medium (supplemented with 0.2% glucose and </span><span "font-family:="" &quot;arial&quot;,sans-serif;color:red;mso-font-kerning:12.0pt"="" style="color: rgb(42, 42, 42);">0.5(0.02%)&nbsp;</span><span "font-family:&quot;arial&quot;,sans-serif;color:black;mso-themecolor:="" text1;mso-font-kerning:12.0pt"="" style="color: rgb(42, 42, 42);">casamino acid). IPTG at various concentrations (0 mM, </span><span "font-size:80.0pt;font-family:symbol;="" mso-ascii-font-family:arial;mso-hansi-font-family:arial;mso-bidi-font-family:="" arial;color:#5b9bd5;mso-font-kerning:50.0pt;mso-char-type:symbol;mso-symbol-font-family:="" symbol"=""><span id="selectionBoundary_1442552977967_1015325584448874" class="rangySelectionBoundary" style="line-height: 0; display: none;">&#65279;</span><font color="#3a96b8">&middot;</font><span id="selectionBoundary_1442552977966_4542458744253963" class="rangySelectionBoundary" style="line-height: 0; display: none;">&#65279;</span></span><span "font-family:&quot;arial&quot;,sans-serif;color:black;mso-themecolor:="" text1;mso-font-kerning:12.0pt"="" style="color: rgb(42, 42, 42);">) (0.2 mM,</span><span "font-family:&quot;arial&quot;,sans-serif;color:black;mso-themecolor:="" text1;mso-font-kerning:50.0pt"="" style="color: rgb(42, 42, 42);"> </span><span "font-size:80.0pt;font-family:symbol;mso-ascii-font-family:arial;="" mso-hansi-font-family:arial;mso-bidi-font-family:arial;color:#ed7d31;="" mso-font-kerning:12.0pt;mso-char-type:symbol;mso-symbol-font-family:symbol"=""><span id="selectionBoundary_1442553009231_3344129309989512" class="rangySelectionBoundary" style="line-height: 0; display: none;">&#65279;</span><font color="#da8044">&middot;</font><span id="selectionBoundary_1442553009231_27489691064693034" class="rangySelectionBoundary" style="line-height: 0; display: none;">&#65279;</span></span><span "font-family:&quot;arial&quot;,sans-serif;color:black;mso-themecolor:="" text1;mso-font-kerning:50.0pt"="" style="color: rgb(42, 42, 42);">), 1 mM,</span><span "font-family:&quot;arial&quot;,sans-serif;color:black;mso-themecolor:="" text1;mso-font-kerning:50.0pt"="" style="color: rgb(42, 42, 42);"> </span><span "font-size:80.0pt;font-family:symbol;mso-ascii-font-family:arial;="" mso-hansi-font-family:arial;mso-bidi-font-family:arial;color:#a5a5a5;="" mso-font-kerning:50.0pt;mso-char-type:symbol;mso-symbol-font-family:symbol"=""><font color="#818181">&middot;</font></span><span "font-family:&quot;arial&quot;,sans-serif;color:black;mso-themecolor:="" text1;mso-font-kerning:50.0pt"="" style="color: rgb(42, 42, 42);">) (5 mM,</span><span "font-family:&quot;arial&quot;,sans-serif;color:black;mso-themecolor:="" text1;mso-font-kerning:12.0pt"="" style="color: rgb(42, 42, 42);"> </span><span "font-size:80.0pt;font-family:symbol;mso-ascii-font-family:arial;="" mso-hansi-font-family:arial;mso-bidi-font-family:arial;color:#ffc000;="" mso-font-kerning:12.0pt;mso-char-type:symbol;mso-symbol-font-family:symbol"=""><font color="#e0bf5c">&middot;</font></span><span "font-family:&quot;arial&quot;,sans-serif;color:black;mso-themecolor:="" text1;mso-font-kerning:12.0pt"=""><font color="#2a2a2a">) was added to the bacterial culture at OD</font><font size="1">600</font><font size ="2"> ~ 0.6. Samples were taken at 5-min &nbsp;and 10-min intervals from IPTG induced and uninduced cultures for </font><a title=""><font color="#2a2a2a">(A) OD600 measurements and (B) cell plating on LB solid medium (CFU count) to determine the percentage (%) of cell survival, respectively.</font></a></span><br /></font><br /></div></div>
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