Team:Newcastle/Metals

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==Lab Work Done==
==Lab Work Done==
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{| border="1"
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|-
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! colspan="2" | Summary of Lab Sessions for Metal Sequestering
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|-
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| <center>'''Date'''</center>
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| <center>'''Description'''</center>         
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|-
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| '''[https://2009.igem.org/Team:Newcastle/Labwork/4_August_2009#Sporulation_Tuning.2FChassis_Team 04/08/09]'''
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| Arrival of the non-germination spores. Preparation of the buffer solution required for the treatment of the spores
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|-
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| '''[https://2009.igem.org/Team:Newcastle/Labwork/7_August_2009#Sporulation_Tuning.2F_Chassis_Team 07/08/09]'''
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| Preparation of the lysozyme stock solution required for treatment of the spores
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|-
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| '''[https://2009.igem.org/Team:Newcastle/Labwork/10_August_2009#Sporulation_Tuning.2F_Chassis_team 10/08/09]'''
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| Re-preparation of the buffer solution required for the treatment of the spores. Pouring of agar plates with the appropriate antibiotics.
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|-
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| '''[https://2009.igem.org/Team:Newcastle/Labwork/11_August_2009#Sporulation_Tuning.2F_Chassis_team 11/08/09]'''
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| Re-pouring the agar plates with the appropriate antibiotics
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|-
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| '''[https://2009.igem.org/Team:Newcastle/Labwork/12_August_2009#Sporulation_Tuning.2FChassis_Team 12/08/09]'''
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| Treatment of the non-germinating <i>cwlD</i> spores using Method A
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|-
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| '''[https://2009.igem.org/Team:Newcastle/Labwork/13_August_2009#Sporulation_Tuning.2FChassis_Team 13/08/09]'''
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| Results for the treatment of the <i>cwlD</i> spores using Method A
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|-
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| '''[https://2009.igem.org/Team:Newcastle/Labwork/17_August_2009#Sporulation_Tuning.2F_Chassis_Team 17/08/09]'''
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| Repeat experiment for the treatment of the <i>cwlD</i> spores using Method A
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|-
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| '''[https://2009.igem.org/Team:Newcastle/Labwork/18_August_2009#Sporulation_Tuning.2F_Chassis_Team 18/08/09]'''
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| Successful results for the treatment of the cwlD spores using Method A. Performed treatment for the double-knockout mutants <i>sleB</i> and <i>cwlJ</i> spores using Method A
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|-
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| '''[https://2009.igem.org/Team:Newcastle/Labwork/19_August_2009#Sporulation_Tuning.2F_Chassis_Team 19/08/09]'''
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| Successful results for the treatment of the double-knockout mutants <i>sleB</i> and <i>cwlJ</i> spores using Method A
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|-
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| '''[https://2009.igem.org/Team:Newcastle/Labwork/25_August_2009#Chassis.2FSporulation_Team 25/08/09]'''
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| Freezing down of the treated non-germinating spores, <i>cwlD</i>, and <i>sleB</i> and <i>cwlJ</i>.
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|-
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| '''[https://2009.igem.org/Team:Newcastle/Labwork/2_September_2009#Chassis_team 02/09/09]'''
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| PCR-ing of gene <i>sleB</i> and <i>cwlJ</i> using primers previously designed and ordered.
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|-
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| '''[https://2009.igem.org/Team:Newcastle/Labwork/3_September_2009#Formal_Lab_Session_-_3rd_September_2009 03/09/09]
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| Attempt to PCR-ing of gene <i>sleB</i> and <i>cwlJ</i> using primers previously designed and ordered again.
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|-
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| '''[https://2009.igem.org/Team:Newcastle/Labwork/4_September_2009#Chassis_team 04/09/09]
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| Redesign PCR primers
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|-
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| '''[https://2009.igem.org/Team:Newcastle/Labwork/8_September_2009 08/09/09]
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| Cloning of sleB
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|}
===References===
===References===

Revision as of 16:17, 21 October 2009


Metal Sequester

Introduction

In order to take up and keep the cadmium from the soil efficiently, we needed to think about a way to cross-link the metal ions to intra-cellular proteins which would end up for the most of it in the spore. If the heavy metal ions were not cross linked to a "sponge protein", it could be lethal to the cell at lower concentration and the cell could end up sporulating too early, or even bursting in the soil, releasing all the heavy metal it has taken up.
From our meeting with Prof. Nigel Robinson on the 18th of March 2009, it was evident that the best way of getting cadmium into the spore is to express a metallothionein, which would 'soak up' the cadmium, which in turn would be trapped within the protein in the spore.

Novelty in this sub-project

To increase the efficiency of our system in sequestering the heavy metal cadmium from the soil, we divised a plan to make sure that most of the metal ions that have been taken in our B.subtilis cell is then rendered bio-unavailable by incorporating it into smtA metallothionein.

SmtA metallothionein protein from E. coli can bind to heavy metals [1,2,3]. They have a tendency to bind to cationic metal ions such as cadmium, copper, arsenic, mercury, silver.

It has been shown that in B.subtilis, in order to express a specific protein in the spore coat, it is possible to make a fusion protein with a spore coat protein called CotC, and a group have successfully expressed antigen proteins which are about the same size as our smtA metallothionein in order to make a vaccine[4]. By fusing CotC spore coat protein from Bacillus subtilis, our smtA metallothionein can be localized to the spore coat, hence we can successfully trap most of the metals ions into the bacterial spores.

It is also fused with GFP reporter gene in order to detect the expression of the fusion protein into the spores using a fluorescence microscopy.

Because we want most of the metals to go into the spore rather than the vegetative cell, we designed our fusion protein so that it is controlled by the native CotC promoter sigK which is activated in sporulation conditions. Therefore, our smtA metal sequester will only be expressed once the cell have made the decision to become a metal container and sporulate, and it will only be expressed in the spore.

BioBrick constructs

Lab Work Strategies


Construction


Synthesised by GeneArt, fragment: 1385 bp DNA

Clone Manager construct and cut map:

Newcastle Metal sequester1.JPG

Sequencher construct:

Newcastle Metal sequester21.JPG


Cloning and Integration

GeneArt will clone the vector into a standard biobrick vector. We will send them Plasmid pSB1AT3 with part BBa_J04450 (mCherry).

BBa_J04450 in pSB1AT3 Clone Manager plamid map:

Newcastle Metal sequester3.JPG

Once we receive this fragment cloned in pSBAT3 we will amplify the part by PCR. Primer 1 will incorporate a HinDIII site and primer 2 will incorporate a BamHI. Checked that these enzymes don’t cut the fragment:

Newcastle Metal sequester4.JPG

We cut the PCR fragment and clone into pMutin4 cut with the same enzymes (diagram below is pMutin2 but this is essentially the same)

Newcastle Metal sequester5.JPG

We then integrate into the 168 chromosome using homology between our cotC fusion and the native copy of cotC.

Testing and Characterisation

Once transformed the spores of the mutant will need to be tested for fluorescence. Two obvious methods:

1) Fluorescence microscopy: grow the cells in sporulation medium and look under the microscope for fluorescent spores.
2) Purify spores and measure their fluorescence in a fluorescence plate reader.
3) We would also test whether the strain is able to absorb cadmium in the spores when compared to the wild-type.

Lab Work Done

Summary of Lab Sessions for Metal Sequestering
Date
Description
04/08/09 Arrival of the non-germination spores. Preparation of the buffer solution required for the treatment of the spores
07/08/09 Preparation of the lysozyme stock solution required for treatment of the spores
10/08/09 Re-preparation of the buffer solution required for the treatment of the spores. Pouring of agar plates with the appropriate antibiotics.
11/08/09 Re-pouring the agar plates with the appropriate antibiotics
12/08/09 Treatment of the non-germinating cwlD spores using Method A
13/08/09 Results for the treatment of the cwlD spores using Method A
17/08/09 Repeat experiment for the treatment of the cwlD spores using Method A
18/08/09 Successful results for the treatment of the cwlD spores using Method A. Performed treatment for the double-knockout mutants sleB and cwlJ spores using Method A
19/08/09 Successful results for the treatment of the double-knockout mutants sleB and cwlJ spores using Method A
25/08/09 Freezing down of the treated non-germinating spores, cwlD, and sleB and cwlJ.
02/09/09 PCR-ing of gene sleB and cwlJ using primers previously designed and ordered.
03/09/09 Attempt to PCR-ing of gene sleB and cwlJ using primers previously designed and ordered again.
04/09/09 Redesign PCR primers
08/09/09 Cloning of sleB

References

1- Cretì, P., F. Trinchella, et al. "Heavy metal bioaccumulation and metallothionein content in tissues of the sea bream Sparus aurata from three different fish farming systems." Environmental Monitoring and Assessment.

2- Morby, A. P., J. S. Turner, et al. (1993). SmtB is a metal-dependent repressor of the cyanobacterial metallothionein gene smtA: identification of a Zn inhibited DNA-protein complex. 21: 921-925.

3- Waldron, K. J. and N. J. Robinson (2009). "How do bacterial cells ensure that metalloproteins get the correct metal?" Nat Rev Micro 7(1): 25-35.

4- Mauriello, E. M. F., L. H. Duc, et al. (2004). "Display of heterologous antigens on the Bacillus subtilis spore coat using CotC as a fusion partner." Vaccine 22(9-10): 1177-1187.




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