Team:Colombia Uniandes/NickoProject

Our Nickel Absorption System!

Nickel is a silvery-white, hard, malleable, and ductile metal. Now days the major use of nickel is in the preparation of alloys which are characterized by their strength, ductility, and resistance to corrosion and heat, such as stainless steel. It is also used for rechargeable batteries, catalysts and other chemicals among others. Most nickel on Earth is inaccessible; this is why the metal is mined in Russia, Australia, Cuba, Canada, Colombia, Venezuela and South Africa[1].

As a result of this activity all kinds of water bodies are being contaminated with metals of this nature, Colombia, is one of the many affected. In small quantities nickel is essential, but when the uptake is too high it can be a dangerous to human health [2] bringing many types of cancer, birth defects, abortions, asthma, allergic reactions such as skin rashes or “nickel-itch”, and many other conditions as its consequences.

Responding to these concerns, we have designed a bacterium which would be capable of absorbing the nickel in its interior using the internal regulating system of nickel belonging to the ''Cupriavidus metallidurans'', to later be removed magnetically, using the property from ''Magnetospirillum magneticum'' AMB-1 which will be used as our final chassis.

Design: Project Parts!

Nickel Removal System

Our construct

Using the nickel homeostatic system of ''E. coli'' and ''Cupriavidus metallidurans'', we will be able to create a system capable to detect and absorb nickel, to later be removed magnetically, using the magnetotactic property from ''Magnetospirillum magneticum'' AMB-1 which will be used as our final chassis.

Nickel removal system's construct

Explanation?

Prcnr is a constitutive promoter, constantly producing RcnR protein which represses PrcnA. When there is nickel in the media RcnR alters its form, making it impossible to bind PrcnA, activating the production of the HoxN protein. This last protein is an efficient nickel transporter form ''Ralstonia metallidurans'' that places in the membrane allowing the income of the metal into the cell, it is one of the most efficent import nickel system reported in a bacterium [3].

Acording to the above, our system is recensusing for nickel everytime, and when this metal is detected, it is absorbed and consequently further increases its absorption.

Our chassis

We chose ''Magnetospirillum magneticum'' AMB-1 as a final chassis this organism has the particularity to produce “magnetosomes” which are vesicles that contain 15 to 20 magnetite crystals that together act like a compass needle to orient magnetotactic bacteria in geomagnetic fields[4]. This property, will allow us to eliminate the bacteria from water with a simple magnetic field.

Reporter for PrcnA

In order to check PrcnA obtained works in the presence of nickel, we will measure the mRFP activity, using our construct not only as a nickel removal system but as a quantitative nickel reporter as well. The color of mRFP is visible(this means, is not necessary a fluorometer to measure its protuction).

Our work in progress!

References

[1] ''Nickel''. U.S. Geological Survey, Mineral Commodity Summaries. January 2013.

[2] Küpper, H. and Kroneck, P. ''Nickel in the Environment and its role in the metabolism of plants and cyanobacteria'' In Nickel and its surprising impact in Nature. Metal ions in life science, Vol. 2, Wiley 2007.

[3] Schaumlöffel, D. et al. '' J. Trace Elemn. Med. Bio.'' 2012, 26, 1-6.

[4] Eitinger, T. ''Microbial Nickel Transport'' In Microbial Transport Systems. Ed. G. Winkelmann. Wiley-VCH 2001.

[5] Blakemore, R. ''Science'' 1975, 190, 377–379.