Applied Design—A Detecting System
For the practical application in the farmland, the farm will be divided into several areas, in each area, several sets of devices and sensors will be installed. The devices in each area will collect the farmland conditions respectively, and the data will be transmitted to one host device in each area through Bluetooth, and then the host will upload the data of its area up to the cloud through WiFi. When the data are uploaded to the cloud, it will send into the app in real time; thus the user can know the conditions in their farm simultaneously. As the time goes by, a database of the environmental information cloud will be created, the farm conditions will become big databases, and according to it, we can use the statistics of the big data to predict the future conditions as the number of pests, and auto-control the spraying system to spray Pantide or water more efficiently and accurately.
(See more in the Device)
What is “Detecoli”?
Pantide, a portmanteau word, conveys two concept－Pan and peptide－in a single blended neologism. In ancient Greek mythology, Pan is a god of shepherds and nature, whereas peptide indicates the essential substance of Pantide, amino acids. Pantide derives its toxicity from the spider venom. The inspiration for Pantide originates from the food chain. Predation is a scene ubiquitously observed in nature. Through evolution, animals have evolved diverse ways of predatory strategy. In this light, we hope to avail the natural evolutionary phenomenon into our project. Spiders are one of the most successful terrestrial venomous creatures on earth. In 300 million years of evolution, spiders have evolved arrays of complex venomous toxins. [1] Therefore, we found its potential for integrating spider toxins as a new source of bioinsecticide.
“More than a hundred different components can be found in the same venom, and in this parameter spiders are leaders in living nature.”
Professor Alexander Vassilevski et al
Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry
Russia
On account of the vast multicomponent mixture in spider toxins, the selection of spider toxin required evaluation in an organized methodology. In this case, first, we searched two online databases－AnachnoServer and UniProt (Universal Protein Resource)－for toxic candidates. AnachnoServer is an online database that contains nearly 800 peptide toxin information from 78 spider species[1], and UniProt is a library of protein information. We selected the toxin peptides from the databases with the following several criteria.
- The toxin should have multiple references which back up the origin, structure, and mechanism.
- The toxin should not be toxic to mammals with the authentication of mice experiment.
- The toxin should not have more than four disulfide bonds because we plan to express the toxin gene in E. coli.
- The toxin was done with some orally-active experiment on certain species.
- The toxin has no antibiotic activity to bacteria.
For the detailed toxin selection process, see toxin selection model.
After months of searching and winnowing, Pantide comes into existence. The three selected toxins are Omega-hexatoxin-Hv1a (Hv1a), μ-segestritoxin-Sf1a (Sf1a) and Orally active insecticidal peptide (OAIP).
Operation Model
We designed a device to sense UV lights and high temperature, and we can confirm if it is working. When the device is working, and has not been exposed to UV light nor high temperature, it will be in the color of light green. When the device is working, and it has been exposed to excess UV lights, it will turn red; and if it has been under high temperature for too long, it will turn blue. However, if the device is not working at all, it won’t be in color (=white). The design of the device can also prevent e-coli from getting out, and the e-coli in it will be Sterilized after use. At the end, it’s free for disposal.
Color changing system
In normal conditions, the color of the sticker will be light green, of which indicates “safe”; nonetheless, if the products were exposed under sunlight or temperature higher than 37 degrees Celsius, the color will change drastically into red or blue respectively, of which indicates “not safe”. The longer the sticker was exposed under bad condition, the darker will the colors blue or red will be. The cause of both color is the synthesis of chromoprotein. Chromoproteins are very stable, which means that the color will last for a long period of time.
Orally Active Insecticidal Peptide (OAIP)
OAIP is a toxic peptide derived from Selenotypus plumipes (Australian featherleg tarantula). It targets the voltage-gated ion channel of insects including species from the orders Lepidoptera and Coleoptera. It causes paralysis and finally death. OAIP is lethal to several insect orders but is not toxic to mice.
Figure 3. The animation shows the 3D structure of OAIP,
created by a software called Cn3D with the peptide information from NCBI.
The three toxins are belong to a major category in spider venom－Short peptides that have disulfide bonds. Most of these toxin peptides have a structural motif that contains cysteine knottings and forms loops. The active site in the peptide that performs its toxicity are the amino acids located in loop regions. [4] The structure of these toxins are so-called “Inhibitor Cystine Knot (ICK)”. ICK has several features based on its disulfide-bond-rich structure－Stability. Take Hv1a as an example for proving the stability of ICK; Hv1a is highly stable in the temperature range of -20°C to 75°C and pH values of 1 to 8. Also, Hv1a is resistant to digestive enzyme－protease K. [5]
Figure 4. ICK structure.
In nature, spiders inject venom into the haemolymph of insects’ that causes the death of the prey. However, Pantide is designed to be ingested by pests after application of Pantide onto the leaves. Therefore, there should be an amelioration done for the design of toxin.
“Many insecticidal venom peptides are typically ineffective, or at least much less potent, when delivered orally and this is thought to be due to the ineffective delivery of the toxins to their active sites of action in the central nervous system or peripheral nervous system.”
Doctor Elaine C. Fitches et al
The Food and Environment Research Agency
United Kingdom
To promote the oral toxicity of toxin peptide, we designed a fusion protein with the addition of lectin. Lectins are glycoprotein-binding proteins. In this case, we chose snowdrop (Galanthus nivalis) lectin as a carrier of toxin peptides to create a fusion protein.[6] Snowdrop Lectin recognizes the glycoproteins on the epithelial cell in the insect gut and facilitates the fusion protein to cross the epithelial cell by transcytosis. Therefore, the fusion proteins are translocated into the haemolymph from the alimentary canal. Also, snowdrop lectin is proved to be resistant to proteolytic activity in the insect gut.[7]
Target
The principal application for our sticker is to monitor the WHOLE transporting process. This is, from the second that the product was made by the factory, to the moment that the customer received the product (even until the customer finishes using the product), every moment was monitored. This not only guarantee the quality of the products, but helps to solve the conflict between the factory and the transport company. When the customers received the products with the stickers on it color changed, it indicates that the transporting condition is not acceptable. Likely, the transport company can also use this kind of stickers to prove to the factory that their employees do treat every cargo properly. This way, we can avoid consumer dispute and the problems of compensation, and add more goodwill for the company.
In addition, what we emphasize is to ensure EVERY product that have our stickers on and to maximize the accuracy of quality control. We extend the monitoring process from initially only in the factory to eventually the customers’ hands, making customers no longer buy, or use, the damaged product caused by inappropriately transporting or storing. The most considerable benefits of this bio-sticker are “long-term monitor” and “cumulative”. The factors of the harmful environments accumulate, and as soon as they surpass the limitation, it activates the color changing process. Still more, the basic material of this bio-sticker is e-coli. As the fact that e-coli replicates itself extremely rapidly, the cost of the sticker will substantially decrease.
