AP Biology class blog for discussing current research in Biology

Author: carleighdioxide

Melanin: Breaking Down Barriers

In a post written by Susan Eckert (teacher) and Shannon Huhn (student), the complex and complicated construct of race is broken down to reveal the true essence of society: genetics and the genetics of the skin. 

Skin is one of the most important parts of our body. Firstly, as we studied in our immune system unit, we know that the skin protects us from sickness and from possible foreign invaders through the non-specific/innate bodily response. Specifically, however, our skin protects us from damage caused by UV light all because of melanin. 

Although we may be familiar with this term as it is oftentimes involved in the conversation of race, research shows that the concept of race is not actually backed by science and the genetics of melanin. Before we can get into this conversation, we must learn about the science behind melanin. Importantly, our bodies contain cells called Melanocytes that produce the pigment called melanin. Through the process of melanogenesis, tyrosine is oxidized, which as we know from class means that it is losing electrons, and enzymes are utilized to produce two kinds of melanin: eumelanin which causes the skin to be dark, and phaeomelanin which causes the skin to be light. Although all of our bodies have the same amount of melanocytes, our skin color is determined by how much eumelanin and/or phaeomelanin is produced. 


With this knowledge, it is easier to engage in conversation on race. Throughout history, skin color has been used to fuel general racial inequalities. Darker skin, whose genetic purpose is to be able to absorb more light, has been wrongfully associated with inferiority while lighter skin, whose genetic purpose doesn’t involve absorbing a lot of light, has been associated with superiority, both based on the grounds of their appearances. Making these assumptions based solely on the physical color of the skin without acknowledging or thinking about the explanatory science should automatically negate these wrongful and incorrect accusations. According to Tiskoff and Kidd, “Humans are ∼98.8% similar to chimpanzees at the nucleotide level and are considerably more similar to each other”. Of course, we must take into consideration the confidence level and margin of error in this statistic, but nevertheless, the percentage is high, showing that race doesn’t make one inferior/superior as we are all essentially the same except for minor genes which produce specific skin colors. In general, it comes down to the production of pigments all based on necessary function.

We must combine what we know about melanin, genetics, skin, and race to move forward in our society. Although all are socially and genetically unique, we are all human on a genetic and molecular level. Conducting research and getting down to the science of various topics carries the necessary substantial weight to create change. What would you like to research next?

Is This a Possible Explanation for COVID-19’s Rapid Transmission?

In a study done by Rommie Amaro and colleagues at the University of California San Diego, Maynooth University (Ireland), and the University of Texas at Austin, it has been discovered that certain Glycans, or a sugar molecule chain bound to the SARS-CoV-2 spike proteins, could be a real reason that SARS-CoV-2 can easily enter our bodies. 

In order for a human– or a host cell– to be infected with COVID-19, the actual virus (SARS-CoV-2) must infiltrate the host cells. As SARS-CoV-2 is covered in spike proteins, these proteins dock up with a host cell receptor called ACE2, which is embedded in the cellular membrane. In order for the virus to successfully dock with the receptor, it must change its shape in order to expose the Receptor Binding Domain (RBD), or exactly where the spike protein docks with ACE2.

At the specific spike protein/ACE2 docking points, the spike proteins are covered in Glycans, or sugar molecules. These glycans have the ability to protect the virus from the host cell’s immune system. Relating the importance of the glycans and the immune system to our class, we have heavily researched the roles of sugars in molecular processes and pathways and the functions of the immune system. With this knowledge, we are able to see, recognize, and understand how powerful and prevalent the glycan is in guarding the virus against our usually strong, organized immune system attacks. As the scientists in the study processed the information about the glycans, they were intrigued to discover how it could possibly lead to easier rates of infection.

To begin, they used dynamic computer models to simulate the glycan-covered spike proteins docked to the ACE2 in the cell membrane. They were able to deduct that the glycans help optimize the spike protein’s effort to expose its RBD. Thus, the glycans actively allowed easier infection through an easier docking experience. However, they also uncovered that the glycans only bound to certain spike proteins, meaning that the immune system, but specifically antibodies, could attack the virus at these docking points. Posing as an extremely positive discovery, the absence of glycans in certain docking points inspired the team to see if they could get rid of the glycans in total. Through Biolayer Interferometry, or technology that allows you to record biomolecular interactions, they were able to successfully mutate the spike protein so it didn’t have glycans anymore– thus, reducing SARS-CoV-2’s ability to bind to ACE2. 

The concept of removing the glycans from the spike proteins has been a major point of research in vaccine production. Although vaccines being made by Pfizer and Moderna are revolved around MRNA, ideas like debilitating the virus-protecting glycans are extremely revolutionary and could lead to possible amazing breakthroughs in the future.

This New Enzyme Could Save Your Future

According to a study done by Professor John McGeehan, the Director of the Center for Enzyme Innovation at the University of Portsmouth, and Dr. Gregg Beckham, a Senior Research Fellow at the National Renewable Energy Laboratory, a new enzyme has been manufactured that can break down trash at rapid speeds and with great effectiveness.

In previous years, scientists discovered and worked on PETase, an enzyme that breaks down PET, a material needed to produce lots of one-time-use plastic items. PETase can break down PET, which stands for polyethylene terephthalate, since the enzyme returns the molecule to its monomer form through depolymerization, a process meant to convert polymers into monomers by increasing the levels of thermal energy. PETase transformed the process of breaking down plastic by being able to do what nature can in 100 plus years in only a few days. As we have learned in our AP Biology class this year, breaking down polymers into monomers is an important process of life. Whether it takes place in our digestive system or in attempts to recycle trash, depolymerization essentially is one aspect of biology that allows life to take place.

Inspired to do more research because of the success with PEtase, the same group of scientists has discovered MHETase, another enzyme that helps to break down waste through the same process as PETase. As we know from class, an enzyme is a typ of protein that speeds up chemical reactions. So when they combined PETase with MHETase, PET was broken down in half of the time that it took PETase alone to break down PET. After that, the scientists physically constructed bonds between PETase and MEHtase by using a microscopic X-ray system in order to be able to see at such a molecular level, and the process of breaking down PET became three times more efficient than when the PETase and the MEHtase were simply just mixed together. This new combination of PETase and MEHtase is commonly referred to as a “super-enzyme” or the enzyme “cocktail”. 

Not only do PETase and MEHtase work well together since they both break down PET, but they both break down PET through different strategies. Together, PETase and MEHtase help to quickly and effectively return the PET to its original, monomer form. Separately, PETase will deconstruct the surface of the PET molecules, while MEHtase will help deconstruct the molecule in its entirety. As a team, PETase and MEHtase will allow for the plastic items containing PET to be recycled and reused, breaking the cycle of disposing of plastics and the initiation of factories to make more. 

As waste truly begins to pile up on Earth, a “super-enzyme” like PETase with MEHtase certainly gives all people some hope for the future of our planet. The whole decomposition process can be made so much faster and so much more efficient with the new enzyme “cocktail”, and hopefully, the production of plastic and PET slows due to this new, groundbreaking discovery. Let us all think upon the effects that this super-enzyme can have; what will be your next steps towards a waste-reduced planet?

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