Bio detection of anoxia in Lake Xochimilco
using modified Escherichia coli
by GenetiX
Instituto Tecnológico y de Estudios Superiores de Monterrey, Campus Ciudad de México
Our Team
Background

Xochimilco:
•
Source of water for the
Metropolitan Area
•
Highly touristic and agricultural
element
•
World Heritage Site
•
Local endemic species in danger
of extinction
•
Highly polluted with indutrial
residues
•
Critical levels of dO2 below
minimun requirements
•
Artificial eutrophication
What is Eutrophication?
6 mg/L
Water
Xochimilco
Movement
of water
Dissolved
Oxygen
Temperature
Factors
Salinity
Pressure
Photosynthesis
Respiration
Eutrophication
Less than
3 mg/L
Eutrophication
Increased
Photosynthesis
Nutrient
Fertilizers
Nitrogen and
Phosphorus
Indicators
Blocking of light to
littoral zone
Microbial
decomposition
Depletion of
dissolved oxygen
Hypoxia
Less than
2.8mg/L
Chlorophyl
Parameter
Oligotrophic
Eutrophic
Average total phosphorus
8.0
84.4
Average total nitrogen
661
1875
Average Chlorophyll a
1.7
14.3
Chlorophyll a. peak concentration
4.2
42.6
Objective

Detection of anormal ferric and anoxia/hipoxia
levels on water samples from the Xochimilco Lake by
using biosensors
2 ppm>[O2]
O2Prom
0.5ppm>[Fe]
Fe Prom
2 ppm<[O2]
0.5ppm<[Fe]
Topic

Biosensors:
•
Fast response in time
•
Fast and continuous measurement
•
High specificity (shape-specific
recognition)
•
Simplicity in its use
•
Capability of measuring
concentrations ranging from 10-18 to
10-19 M, so we need low sample
requirements
•
Real time measurements
Justification
• Acceptable levels of disolved iron in water: 0.5
ppm
• Iron promoter minimal iron dissolution
concentration: 1 ppm
• Oxygen Promoter Works in dO2 concentrations
over 0.2 ppm
• dO2 levels in Xochimilco vary around 3 ppm
• Minimal requirement of dO2 for wild-life
sustainance 6 ppm
• Detection of quantitative values of GFP and RFP
by Flow Cytometry
Our Biosensor
Methodology & Results
A
B
+ Bacteria
Transformation
Heat
Shock
20 hours
37° C
A
A
B
Concentrated DNA
B
Transformed
Bacteria
A
A
B
B
Methodology & Results
A
B
Check +enzymes
Concentrated DNA
+Enzymes
Expected Pattern
Cut Bands
A
A
B
Agarose Gel
Ligation
B
Methodology & Results
Oxygen Promoter + G.F.P
Iron Promoter + G.F.P
Oxygen Promoter + mR.F.P.
EcoRI
Pstl
Discussions
Conclusions
Construction of biosensors was not completed
due to what appear to be flawed ligations
and/or low efficiency competent cells.
Future Work

Completion of the biosensors

Proof of concept growing bacteria in absence
and presence of stimuli

Quantitative measurement of disolved O₂ and
Fe in various concentrations for construction of
a photoluminescent scale.

Application of biosensors to a range of samples
from specific points distributed all along
Xochimilco lake.
Posada Tec 2013
Travesuras 2014
Synthetic Biology Conference
Thanks

ITESM CCM

Hidrosina

GoNext Project

Tecnologico de Monterrey campus Mty.

Nautilus

Tolerantum

QFB. Isabel Coria
Special Thanks

M.Sc. Lamberto Álvarez-Palacios

Luis Vaca Dominguez M.D. Ph. D.

Alicia Sampieri García Ph. D.