Team:UNAM-Genomics Mexico/Project

Overall project

The Idea

Synthetic Biology has been enabling changes in all bio-domains, one such being communication. Cellular communication has relied since time immemorial on chemical messengers to exchange information. As such, these messengers regardless of their scope, are constrained to a chemical system; even far reaching messengers such as hormones are bound within the chemical system that is the human body. But this mode is about to change.

In this project, our goal is to render the chemical barrier deprecated by using a non-chemical messenger: photons. These will transport information between cells that have been designed to sense and emit light, thus creating a photon-based inter-cellular communication system.

These messengers are produced through bio-luminescent reactions, and are quite capable of traversing multiple environments. Consecuently, this enables the propagation of information beyond the chemical, biological and even spatial restrictions. As the messenger is effectively decoupled from the chemical layer, it is a natural step in the communications bridge between organic-based and silicon-based systems, such as computers.

The Name

As you might imagine, WiFi is a play on the popular IEEE 802.11 communications standard knows as Wi-Fi. Since our systems achieves the transfer of information without wires, it is thus wireless. As for fidelity, we shall see.

Before you begin wondering on Copyright issues, let us make two things clear:

• Our name is WiFi, not the [http://www.wi-fi.org/ Wi-Fi Alliance]'s Wi-Fi (notice the hyphen).
• Second, a quick search on the US Patents & Trademarks Office [http://tess2.uspto.gov/ Trademark Electronic Search System (TESS)] returned that WiFi was a trademark in 2006, but is now listed as "Dead". Therefore, we are not infringing copyright issues by using it in our system.

Project Details

The process of transferring information from a sender entity to a receiver one through a determined channel is called communication. Biological entities have relied since time immemorial on chemical messengers to relay information; this holds true for multicellular organisms as well as for populations of unicellular organisms. Being chemical based, these messengers are constrained to a chemical system regardless of the scope of said system, eg: even far reaching messengers such as hormones are bound within the chemical system that is the human body.

In this project, our goal is to render the chemical barrier deprecated by enabling chemical-free communication. This has been translated to the implementation of a non-chemical messenger, in this case, photons. Our channel is thus light based; packages of photons, or energy quanta, will transport information from senders to receivers, effectively bypassing most chemical barriers in-between. Consequently, our communicating system is no longer contained within a chemical system, but within a physical one, ie: there must remain a physical channel where photons can be transported. This physical channel may range from something as sophisticated as a microcontroler-based electronic relay system, to something as simple as vacuum (or void). However, this physical layer proves very well to be impervious to most chemical signaling. Ergo, the chemical system's signaling would remain unaffected by the physical channel, and vice versa. In consequence, the exchange of information through physical means is sufficiently independent from the information encoded in the system's endogenous chemical pathways. In other words, it is extraordinarily uninvasive. As an added bonus, our receiver entities are easily transformed into emitter entities. Thus, by using our cells as information processing chassis, we can expand the communications layer. We can effectively render our system one where information is:

• Encoded and sent by an emitter
• Recieved and decoded by a receiver
• Plus processed, transformed, and relayed forth

Our ambicious implementation is based on well known systems, mainly bioluminescent proteins from Photinus pyralis and Vibrio fischeri, as well as photoactive receptors like Cyanobacteria cyanobacteriochromes and Light-Oxygen-Voltage domain quimeric proteins. We thus exploit the fact that cells already display primitive photo-communication, both within multicellular organisms as well as within populations of unicellular ones. Moreover, in our system the photonic information is transformed to and from chemical information within the chemical system that is an individual cell. Thus, the chemical barrier that is the membrane has ceased being a barrier to communication and is now a noise isolator. By decoupling the messenger from the chemical layer, we enable a brand new host of applications that were previously unavailable, ranging in domains from neurobiology, to cybernetic coupling, and even to biological telecommunications.

Reception

General mechanisms

Inside the cells many networks of interacting proteins that sense the environmental conditions and enable appropriate biochemical reactions to take place, are maintained by the transfer of information that often consists of highly specific conformational changes within and between proteins. <ref>Vendruscolo, Michele. 2008. "Protein dynamics under light control.." Nature chemical biology 4:449-50. http://www.ncbi.nlm.nih.gov/pubmed/18641621. </ref>

Photosensory proteins present in plants, bacteria, cyanobacteria, and fungi; undergo the transfer of information by binding light-absorbing chromophores or cofactors to convert the energy of photons into structural and dynamical changes, regulating cellular processes ranging from energy production to virulence. [Photoregulation]

This mechanism of light sensing as a means of informational transfer has been applied to the challenge of designing proteins with novel input-output relationships. The fact that many photoreceptors and signaling proteins are constituted of modular functional domains has helped to achieve this attempt.

We plan on using a cyanobacteria phytochrome-like domain coupled to an EnvZ kinase to sense incoming red light and translate it into a signal detectable by the cell, in this case phosphorilated OmpR. This brilliant system was a construction known as [http://partsregistry.org/Coliroid Coliroid] for the 2004 iGEM by the University of Texas at Austin and UCSF iGEM team. This system acts as an <IF ! LIGHT> logic gate. We are contemplating the use of distinct assemblies to obtain a direct <IF LIGHT> logic gate.

Our second sensing device is based on another BioBrick Part: [http://partsregistry.org/Part:BBa_K191003 LOVtap]. This TF dimerizes when struck by blue light, thus activating the transcription of a determined promoter's coding sequence.

Our final input device is based on a newfound OmpR-like system of Synechocystis. This system uses a sensing protein (CcaS) than shows kinase activity when struck by green light. It then proceeds to phosphorilate a regulatroy TF (CcaR). This TF then starts transcription of its associated promoter's coding sequence.

Emission

We plan on using a mutated version of Photinus pyralis luciferase to generate red light. In addition, we will be using a newfound enzyme called Luciferin Regenerating Enzyme to recycle said substrate.

For the blue and green emissions, we will be using the Lux Operon from Vibrio fischeri. We plan on taking advantage of the lumazine BioBrick part to generate a blue-shifted light (around 450nm), as well as the LuxY of strain Y-1 to generate a red-shifted light (around 550nm).

Application

While glowing bacteria are nothing new, photo-communicating bacteria are something quite rare. We plan on using this advantage on several applications as a proof-of-principle. This may include an oscillator, a bio-cable, cell-phone-using bacteria, among others...

Results

(None yet... but check back soon!)

References