Team:University College London/Module 3/Modelling

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! Number !! Reaction !! Reaction rate (molecules/sec) !! Notes
! Number !! Reaction !! Reaction rate (molecules/sec) !! Notes
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|-
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| R1 || PE + POPex ↔ PEPOPex|| Forward: 1000
+
| R1 || PE + POPex ↔ PEPOPex || Forward: 1000
Backward: 1 || Pops have 1000 times greater tendency to adhere to plastic than float free in the ocean
Backward: 1 || Pops have 1000 times greater tendency to adhere to plastic than float free in the ocean

Revision as of 17:58, 20 September 2012

Module 3: Degradation

Description | Design | Construction | Characterisation | Modelling | Results | Conclusions

Modelling

Our gene network model for this module shows the amount of laccase produced by our bacteria. We have used this prediction to find out how many bacteria would be required per cubic meter of sea water in order to effectively degrade polyethylene-based plastics.

Species Initial value (molecules) Notes
PE 0.00345
Lex 0.0
PEPOPex 9.24E-5
POPin 0.5 Dependent on the concentration gradient: when the conc. in is equal to conc. out rate decreases testtestselkjalsfdkjalfkjs;lkdjf;laksjdf;laksjdf;lakjs;dljaf;slkdjfazlskdj;falskjd
Nahr 0.0 Produced all the time, transcription depends on
POPinNahR 0.0 Hill function
Lin 0.0
Number Reaction Reaction rate (molecules/sec) Notes
R1 PE + POPex ↔ PEPOPex Forward: 1000

Backward: 1 || Pops have 1000 times greater tendency to adhere to plastic than float free in the ocean

R2 POPex ↔ POPin Forward: 0.6

Backward: 0.4 || Based on membrane permeability: diffusion gradient

R3 POPin + mRNA.Nahr → POPin.mRNA.Nahr Forward: 1

Backward: 0.0001 || The chemical structure/size of POPs is similar to salycilate which is the original compound that react to mRNA.Nahr -> 0 (??)

R9 0 → mRNA.Nahr Forward: 0.088

Backward: 0.6 || Transcription rate of NahR in molecules/sec (for NahR size 909 bp2, transcription rate in E.coli 80bp/sec)

R4 POPinmRNANahr → POPinmRNANahr.Psal Forward: 78200

Backward: 0.191 ||

R5 POPexmRNANahr.Psal → Lin.mRNA 0.054 Transcription rate of Laccase in molecules/sec (for laccase size 1500 bp1, transcription rate in E.coli 80bp/sec)
R6 Lin.mRNA → Lin 0.04 Translation rate of Laccase in molecules/sec (for laccase size 500 aa, translation rate in E.coli 20aa/sec)
R11 Lin → Lindegp 0.03
R7 Lin → Lex Forward: 0.9

Backward: 0.1 ||

R8 Lex → PEdegp Vm: 0.01

Km: 0.114 ||

Degradationnet.jpg

We ran three simulations in SimBiology, each over a different timespan:

Deg1.png comment here?

Deg2.png comment here?

Deg3.png comment here?

1. Laccase size: http://partsregistry.org/Part:BBa_K729002

2. NahR size: http://www.xbase.ac.uk/genome/azoarcus-sp-bh72/NC_008702/azo2419;nahR1/viewer

3. Mato Y, Isobe T, Takada H, Kanehiro H, Ohtake C, Kaminuma T (2001) Plastic Resin Pellets as a Transport Medium for Toxic Chemicals in the Marine Environment. Environ. Sci. Technol. 35: 318-324

4. Teuten E, Saquing J, Knappe D et al. (2009) Transport and release of chemicals from plastics to the environment and to wildlife. Philosophical transactions of the Royal Society of London 364: 2027-2045

8. Young K, Silver LL (1991) Leakage of periplasmic enzymes from envA1 strains of Escherichia coli. J Bacteriol. 173: 3609–3614

11.Van A, Rochman C, Flores E, Hill K, Vargas E, Vargas S, Hoh E (2012) Persistent organic pollutants in plastic marine debris found on beaches in San Diego, California. Chemosphere 86: 258-263

12. Santo M, Weitsman R, Sivan A (2012) The role of the copper-binding enzyme - laccase - in the biodegradation of polyethylene by the actinomycete Rhodococcus ruber. International Biodeterioration & Biodegradation 208: 1-7