GMO: How Safe is Our Food?

Catalyst Volume 10

For thousands of years, humans have genetically enhanced other living beings through the practice of selective breeding. Sweet corn and seedless watermelons at local grocery stores as well as purebred dogs at the park are all examples of how humans have selectively enhanced desirable traits in other living creatures. In his 1859 book On the Origin of Species, Charles Darwin discussed how selective breeding by humans had been successful in producing change over time. As technology improves, our ability to manipulate plants and other organisms by introducing new genes promises both new innovations and potential risks.

Genetically modified organisms (GMOs) are plants, animals, or microorganisms in which genetic material, such as DNA, has been artificially manipulated to produce a certain advantageous product. This recombinant genetic engineering allows certain chosen genes, even those from unassociated species, to be transplanted from one organism into another.¹ Genetically modified crops are usually utilized to yield an increased level of crop production and to introduce resistance against diseases. Virus resistance makes plants less susceptible to diseases caused by insects and viruses, resulting in higher crop yields.

Genetic enhancement has improved beyond selective breeding as gene transfer technology has become capable of directly altering genomic sequences . Using a “cut and paste” mechanism, a desired gene can be isolated from a target organism via restriction enzymes and then inserted into a bacterial host using DNA ligase. Once the new gene is introduced, the cells with the inserted DNA (known as “recombinant” DNA) can be bred to generate an advanced strain that can be further replicated to produce the desired gene product.¹ Due to this genetic engineering process, researchers have been able to produce synthetic insect-resistant tomatoes, corn, and potatoes. Humans’ ability to modify crops has improved yields and nutrients in a given environment, becoming the keystone of modern agriculture.² Despite these positive developments, skepticism still exists regarding the safety and societal impact of GMOs.

The technological advancement from selective breeding to genetic engineering has opened up a plethora of possibilities for the future of food. As scientific capabilities expand, ethics and ideals surrounding the invasive nature of the production of GMOs have given rise to concerns about safety and long-term impacts. According to the Center for Food Safety, GMO seeds are used in 90 percent of corn, soybeans, and cotton grown in the United States.² Because GMO crops are so prevalent, any negative ecological interactions involving a GMO product could prove devastating for the environment.

While the dangers of genetic modification are being considered, genetic engineering has proven to have benefits to human health and the farming industry. Genetically modified foods maintain a longer shelf life, which allows for the safe transport of surplus foodstuffs to people in countries without access to nutrition-rich foods. Genetic engineering has supplemented staple crops with vital minerals and nutrients, , helping fight worldwide malnutrition. For example, Golden rice is a genetically-modified variant of rice that biosynthesizes beta-carotene, a precursor of vitamin A.³ This type of rice is intended to be produced and consumed in areas with a shortage of dietary vitamin A, which is a deficiency that kills 670,000 children each year. Despite the controversial risks, genetic engineering of crops promises to continually increase the availability and durability of food.

References

1. Learn.Genetics. http://learn.genetics.utah.edu/content/science/gmfoods/ (accessed Sep 20, 2016)
2. Fernandez-Cornejo, Jorge, and Seth James Wechsler. USDA ERS – Adoption of Genetically Engineered Crops in the U.S.: Recent Trends in GE Adoption. USDA ERS – Adoption of Genetically Engineered Crops in the U.S.: Recent Trends in GE Adoption. https://www.ers.usda.gov/data-products/adoption-of-genetically-engineered-crops-in-the-us/recent-trends-in-ge-adoption.aspx (accessed Sep 30,2016)
3. Dan Charles. In A Grain Of Golden Rice, A World Of Controversy Over GMO Foods. http://www.npr.org/sections/thesalt/2013/03/07/173611461/in-a-grain-of-golden-rice-a-world-of-controversy-over-gmo-foods (accessed Sep 24, 2016)

Green Sea Turtles: A Shell of What They Once Were

Catalyst Volume 10

Sea turtles appear in many cultures and myths, and are often beloved symbols of longevity and wisdom. However, in spite of the cultural respect shown towards them, green sea turtles have gradually become endangered due to factors such as nesting habitat loss, pollution, egg harvesting, climate change, and boat strikes. Now, there’s a new, even more dangerous threat on the block: herpes. And no, it’s not the herpes you’re thinking of - this kind, known as fibropapillomatosis (FP), is much, much worse.

FP has been observed across all species of sea turtles for years, but it has recently become especially widespread among green sea turtles (Chelonia mydas). The alarming incidence of FP is exacerbating the decline of this already vulnerable population. Among green sea turtles, the number of cases of FP increased 6000% from the 1980s to the mid-1990s, with FP becoming so globally pervasive that the outbreak has been classified as “panzootic,” the animal equivalent of “pandemic.” Now, you might think, “That sounds bad, but why are these turtles dying?” In humans, herpes is unpleasant, but it is seldom life-threatening. Unfortunately, in green sea turtles, the outlook isn’t nearly as optimistic. FP causes the development of tumors on the soft tissues, the shells, and even the eyes of infected turtles. When these growths are left untreated, they can grow to immense sizes, impairing the animal's vital activities, such as breathing and swallowing. So, while the tumors aren’t directly lethal, they invite hordes of secondary infections and pathogens that ultimately result in death.

To make matters worse, treatment for FP is still in development. A landmark study identified the specific pathogen responsible for FP as Chelonid herpesvirus 5 (ChHV5), a close relative of human genital herpes.¹ This discovery was the first step to a cure, but it raised an important question - how had this variant of herpesvirus become so prevalent? Until recently, the answer to that question was elusive.

Fortunately, several recent discoveries offered new explanations for FP’s rise. One study reported a significant positive correlation between serum concentrations of heavy metals and the severity of FP, as well as a significant negative correlation between serum cholesterol concentrations and FP.² In a related find, a team at the University of São Paulo discovered that many green sea turtles have been exposed to organochlorine compounds, which are known to have carcinogenic effects.³ Further research could potentially determine a direct causal relationship between the development of FP and exposure to heavy metals or organochlorine compounds. If such a relationship were found, projects that strive to decrease the prevalence of said compounds in the turtles’ habitats could prove effective in mitigating the spread of FP.

So what’s the prognosis for the green sea turtle? Unfortunately, even knowing what we now know, it may not be good. A study by Jones et. al. found almost all of the infected turtles are juveniles, potentially creating a big problem for the population.⁴ Jones believes the most optimistic explanation for this trend is that current adults and hatchlings have never been exposed to the disease, so only one generation (the juveniles) has been infected. Another optimistic possibility is that once infected turtles recover from the disease, they will simply acquire immunity as adults. However, there is another, devastating possibility: all of the affected juveniles will perish before they reach adulthood, leaving only the unaffected alive and dooming the species. In a heartbreaking aside, Jones reported that FP “grows on their [the turtles’] eyes, they can't see predators, they can't catch food, so sometimes they slowly starve to death — it's not a nice thing for the turtles to experience. Severely affected turtles are quite skinny and have other pathogens affecting them – that’s why they die.”

Eradicating such a devastating disease will no doubt take many more years of specialized research, and significant efforts are needed immediately to rehabilitate the green sea turtle population. Luckily, conservation groups such as The Turtle Hospital, located in the Florida Keys, are making an active effort to save infected sea turtles. They perform surgeries that remove FP tumors, rehabilitate the turtles, and then release them back into the wild. In addition, they collaborate with universities to study the virus and educate the public on sea turtle conservation. To date, the Turtle Hospital has successfully treated and released over 1,500 sea turtles. Through the hard work of conservation organizations and researchers across the globe, we may still be able to save the green sea turtle.

References

1. Jacobson, E. R. et al. Dis. Aquat. Organ. 1991, 12.
2. Carneiro da Silva, C., et al. Aquat. Toxicol. 2016, 170, 42-51.
3. Sánchez-Sarmiento, A. M. et al. J. Mar. Biol. Assoc. U. K. 2016, 1-9.
4. Jones, K., et al. Vet. J. 2016, 212, 48-57.
5. Borrowman, K. Electronic Theses and Dissertations. 2008
6. Monezi, T. A. et al. Vet. Microbiol. 2016, 186, 150-156.
7. Herbst, L. H. et al. Dis. Aquat. Organ. 1995, 22.
8. The Turtle Hospital. Rescue, Rehab, Release. http://www.turtlehospital.org/about-us/ (accessed Oct. 4, 2016).

Graphene Nanoribbons and Spinal Cord Repair

Catalyst Volume 10

The same technology that has been used to strengthen polymers¹, de-ice helicopter wings², and create more efficient batteries³ may one day help those with damaged or even severed spinal cords walk again. The Tour Lab at Rice University, headed by Dr. James Tour, is harnessing the power of graphene nanoribbons to create a special new material called Texas-PEG that may revolutionize the way we treat spinal cord injuries; one day, it may even make whole body transplants a reality.

Dr. Tour, the T.T. and W.F. Chao Professor of Chemistry, Professor of Materials Science and NanoEngineering, and Professor of Computer Science at Rice University, is a synthetic organic chemist who mainly focuses on nanotechnology. He currently holds over 120 patents and has published over 600 papers, and was inducted into the National Academy of Inventors in 2015.⁴ His lab is currently working on several different projects, such as investigating various applications of graphene, creating and testing nanomachines, and the synthesizing and imaging of nanocars. The Tour Lab first discovered graphene nanoribbons while working with graphene back in 2009.⁵ Their team found a way to “unzip” graphene nanotubes into smaller strips called graphene nanoribbons by injecting sodium and potassium atoms between nanotube layers in a nanotube stack until the tube split open. “We fell upon the graphene nanoribbons,” says Dr. Tour. “I had seen it a few years ago in my lab but I didn’t believe it could be done because there wasn’t enough evidence. When I realized what we had, I knew it was enormous.”

This discovery was monumental: graphene nanoribbons have been used in a variety of different applications because of their novel characteristics. Less than 50 nm wide ( which is about the width of a virus), graphene nanoribbons are 200 times stronger than steel and are great conductors of heat and electricity. They can be used to make materials significantly stronger or electrically conductive without adding much additional weight. It wasn’t until many years after their initial discovery, however, that the lab discovered that graphene nanoribbons could be used to heal severed spinal cords.

The idea began after one of Dr. Tour’s students read about European research on head and whole body transplants on Reddit. This research was focused on taking a brain dead patient with a healthy body and pairing them with someone who has brain activity but has lost bodily function. The biggest challenge, however, was melding the spine together. The neurons in the two separated parts of the spinal cord could not communicate with one another, and as a result, the animals involved with whole body and head transplant experiments only regained about 10% of their original motor function. The post-graduate student contacted the European researchers, who then proposed using the Tour lab’s graphene nanoribbons in their research, as Dr. Tour’s team had already proven that neurons grew very well along graphene.

“When a spinal cord is severed, the neurons grow from the bottom up and the top down, but they pass like ships in the night; they never connect. But if they connect, they will be fused together and start working again. So the idea was to put very thin nanoribbons in the gap between the two parts of the spinal cord to get them to align,” explains Dr. Tour. Nanoribbons are extremely conductive, so when their edges are activated with polyethylene glycol, or PEG, they form an active network that allows the spinal cord to reconnect. This material is called Texas-PEG, and although it is only about 1% graphene nanoribbons, this is still enough to create an electric network through which the neurons in the spinal cord can connect and communicate with one another.

The Tour lab tested this material on rats by severing their spinal cords and then using Texas-PEG to see how much of their mobility was recovered. The rats scored about 19/21 on a mobility scale after only 3 weeks, a remarkable advancement from the 10% recovery in previous European trials. “It was just phenomenal. There were rats running away after 3 weeks with a totally severed spinal cord! We knew immediately that something was happening because one day they would touch their foot and their brain was detecting it,” says Dr. Tour. The first human trials will begin in 2017 overseas. Due to FDA regulations, it may be awhile before we see trials in the United States, but the FDA will accept data from successful trials in other countries. Graphene nanoribbons may one day become a viable treatment option for spinal injuries.

This isn’t the end of Dr. Tour’s research with graphene nanoribbons. “We’ve combined our research with neurons and graphene nanoribbons with antioxidants: we inject antioxidants into the bloodstream to minimize swelling. All of this is being tested in Korea on animals. We will decide on an optimal formulation this year, and it will be tried on a human this year,” Dr. Tour explained. Most of all, Dr. Tour and his lab would like to see their research with graphene nanoribbons used in the United States to help quadriplegics who suffer from limited mobility due to spinal cord damage. What began as a lucky discovery now has the potential to change the lives of thousands.

References

1. Wijeratne, Sithara S., et al. Sci. Rep. 2016, 6.
2. Raji, Abdul-Rahman O., et al. ACS Appl. Mater. Interfaces. 2016, 8 (5), 3551-3556.
3. Salvatierra, Rodrigo V., et al. Adv. Energy Mater. 2016, 6 (24).
4. National Academy of Inventors. http://www.academyofinventors.org/ (accessed Feb. 1, 2017).
5. Zehtab Yazdi, Alireza, et al. ACS Nano. 2015, 9 (6), 5833-5845.