AP Biology class blog for discussing current research in Biology

Author: Allisteric Site

If You Give A Mouse…Sight!

In a recent study published in the Journal Of Experimental Medicine, researchers in China successfully used CRISPR Gene-Editing technology to restore sight to mice with retinitis pigmentosa.

That’s a lot of vocabulary all at once, so let’s establish some definitions first and foremost.  According to the National Eye Institute, retinitis pigmentosa is a “genetic disease that people [and animals] are born with…that [affects] the retina (the light-sensitive layer of tissue in the back of the eye)”. As for CRISPR Gene-Editing technology, YG Topics defines it as, “a unique technology that enables geneticists and medical researchers to edit parts of the genome by removing, adding or altering sections of the DNA sequence”.

Most inherent forms of blindness and loss-of-vision stem from genetic mutations, and thus retinitis pigmentosa is one of many forms of genetically caused blindness.  However, through CRISPR technology, the researchers in the study successfully edited the DNA of mice who had the mutation to eliminate retinitis pigmentosa and give them the ability to see.  The results of the study are very promising, as not only does retinitis pigmentosa affect mice, but human beings.  Thus, there is evidence that CRISPR could be used to cure blindness among everyday people.  Kai Yao, a professor from the Wuhan University of Science and Technology who contributed to the study said, “The ability to edit the genome of neural retinal cells, particularly unhealthy or dying photoreceptors, would provide much more convincing evidence for the potential applications of these genome-editing tools in treating diseases such as retinitis pigmentosa”.

In AP Biology, we discussed how DNA factors into the traits of a living being.  DNA is made up of 3 base codons that form up to 20 different amino acids.  These amino acids code for specific proteins.  Through a process of DNA transcription and translation, the DNA uses various forms of RNA to code for proteins, which help tell the cell what to do.  Thus, the way the cell acts is largely determined by its DNA.  Essentially, DNA codes certain traits through various amino acid sequences.  Mutations and alternations to amino acid sequences cause different traits, such as red hair, blue eyes, or blindness.

Thus, successfully altering the DNA of mice has huge implications for the human race.  CRISPR could potentially be used to edit the DNA of humans, and thus help limit and prevent certain genetic conditions.  Many diseases are based on genetic mutations, and if CRISPR Gene Editing technology is proven successful, we could potentially eliminate genetic diseases in a few decades.  While “much work still needs to be done to establish both the safety and efficacy” of CRISPR technology, some groundbreaking scientific treatments could be coming sooner than you think (Neuroscience News).

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A “Coffee-With-Milk” A Day Keeps The Doctor Away

In a recent study, researchers at the Department of Food Science, in collaboration with researchers from the Department of Veterinary and Animal Sciences, at the University of Copenhagen have discovered evidence that the mixture of coffee and milk has anti-inflammatory effects when consumed.

On January 30th, a study was published in the Journal of Agricultural and Food Chemistry (led by Professor Marianne Nissen Lund) that explains how this common combination of ingredients can limit inflammation.  To test the theory, the study “applied artificial inflammation to immune cells.  Some cells received various doses of polyphenols that had reacted with an amino acid, while others only received the same doses. A control group received nothing” (Science Daily).

The results showed that cells that received a dosage of polyphenols and amino acids were twice as effective as cells that received purely polyphenols.  Now, you may be asking how this relates to coffee and milk?  The answer to this question lies in the definitions of terms used above.  Polyphenols are a “category of plant compounds that offer health benefits” (Healthline).  They are found in coffee beans, and therefore, coffee.  Amino acids are “molecules that combine to form proteins,” and therefore are found in a majority of animal products, including milk (Medline Plus).

It is an established fact in the scientific community that polyphenols and amino acids bond, and therefore, the link between the two substances and anti-inflammatory effects is believable to scientists after the recent study performed by the Department of Food Science.  Furthermore, considering how common both substances are, it is likely that a similar reaction occurs when protein is combined with other fruits and vegetables with high amounts of polyphenol.  According to Marianne Nissen Lund, “I can imagine that something similar happens in, for example, a meat dish with vegetables or a smoothie, if you make sure to add some protein like milk or yogurt”.

The immune system is incredibly important to the function of the human body, as it serves to maintain order and defend against both foreign and local threats. When pathogens are able to infiltrate the body, they trigger innate immunity defenses, which in turn causes inflammation (as histamines which are released dilate local blood vessels and increase capillary permeability and cause the area to swell with fluid, which thus, causes inflammation).

Although immune cells (and in particular, innate immunity) cause inflammation, it is also the job of the immune system to limit inflammation by fighting off any unwanted antigen quickly, as the faster the antigen is killed, the faster inflammation goes away.  Immune cells of all types serve this function, ranging from innate to adaptive.  Thus, a compound that can increase the reaction rate of immune cells is incredibly valuable to animal health, including human health.

The results of the study show that polyphenols that have reacted with amino acids can double the effectiveness of the anti-inflammatory process of immune cells.  So, next time you are ordering a coffee, remember to ask for a splash of milk – you just might thank me later.

Coffee with milk (563800) (cropped)

NMT5: A New Enemy To SARS-CoV-2?

In the past few months, scientists in the United States have developed a potential new antiviral to SARS-CoV-2.   The drug, called NMT5, is effective against several variants of SARS-CoV-2, the virus that sent the planet into lockdown only a few years ago.

As stated in the journal Nature Chemical Biology, NMT5 coats SARS-CoV-2 particles as they travel through the body.  Thus, when the virus attempts to attach to the ACE2 receptor proteins of the cell, NMT5 attaches first.  The drug changes the shape of the cell’s receptor upon attachment, which makes it harder for SARS-CoV-2 to infect the cell, and on a larger scale, the organism’s body.

In order to ensure that the drug isn’t toxic, researchers tested NMT5 on healthy cells.  According to the National Institute Of Health, it was “found that NMT5 was non-toxic and only changed receptors that were being targeted by the virus. These effects lasted for only about 12 hours, meaning the receptors functioned normally before and after treatment”.  In fact, in an experiment that used hamsters as models for the human immune system, NMT5 reduced SARS-CoV-2’s ability to bond to ACE2 receptors by 95%!

A significant reason NMT5 is so effective is that it not only limits one particle of SARS-CoV-2, but the effectiveness of the virus as a whole, when present. When a SARS-CoV-2 particle with NMT5 attaches to an ACE2 receptor, it adds a nitro group to the receptor, which limits the ability of the particle to attach to the receptor for 12 hours by changing the receptor’s shape.  Thus, no COVID-19 particle can attach to the ACE2 receptor – even ones that haven’t been surrounded by NMT5.  Stuart Lipton, a professor at The Scripps Research Institute, states that “what’s so neat about [NMT5] is that we’re actually turning [SARS-CoV-2} against itself”, as particles surrounded by NMT5 serve to limit the ability of other SARS-CoV-2 particles.  The drug has excited scientists studying SARS-CoV-2 around the world, as they have “realized [NMT5] could turn the virus into a delivery vehicle for its own demise” (PTI, The Tribune India).

Cell reception and signaling are incredibly important to both viruses and the human immune system.  A virus works by infiltrating a cell through cell receptors that line the outside of the desired cell’s phospholipid bilayer.  Viruses attach to these receptors and infect the cell as a result.  SARS-CoV-2’s process is depicted below, as it attaches to the ACE2 receptors described earlier.  The immune system works by recognizing the virus at hand and signaling B-Lymphocytes and T-Lymphocytes to destroy the virus and infected cells.  B-Plasma cells surround the virus, as shown below, which neutralize it and allow it to be engulfed and destroyed by macrophages.  Cytotoxic T-cells kill cells already infected by the virus.  Both B and T Lymphocytes are activated as a result of T-Helper cells, as T-Helper recognize the virus when a piece of it is displayed at the end of a macrophage, and signal the Lymphcytes by releasing cytokines (another example of cell reception and signaling).  This process is all shown in the image below, with the specific virus depicted being SARS-CoV-2.


However, NMT5 prevents the initial infection from happening when SARS-CoV-2 enters the human body by bonding with SARs-CoV-2 particles before they attach to cells, which allows for the immune system to quickly destroy the virus.  By blocking SARS-CoV-2’s access to receptors, the drug stops the particle before it can infect a cell and do any damage. Since cell receptors are specifically shaped, and any change in form results in a loss of normal function, the ensuing change in shape of a receptor limits any SARS-CoV-2 particle from attaching to said receptor, further limiting the virus’s damage by blocking cell reception from occurring. Thus, the immune system kills the virus without major symptoms.

All in all, the development of NMT5 is exciting for scientists all around the globe.  If it is as effective as studies show, it could play a major role in limiting the effects of SARS-CoV-2.  Hopefully, all goes well, and you should be hearing a lot more about the drug sometime soon.

If you have any updates or questions on NMT5, I invite you to share them in the comments below.  Thank you for reading my blog post, and stay curious!

The Failure Of The Endangered Species Act

In a recent study, biologists at the Columbia Climate School have determined why the Endangered Species Act fails to protect endangered species throughout America.  The Endangered Species Act (ESA), passed in 1973, provides programs and guidelines for protecting and rehabilitating endangered plants and animals throughout the country.

On October 12th, the Columbia Climate School posted a study (led by Environmental biologist Erich Eberhard) that broke down why the ESA has been unsuccessful.  However, in the 39 years since the act was passed, it has failed to recover a single endangered species to the point where it no longer needs protection.  While eleven species have been delisted from endangerment status, biologists claim none of them are due to the ESA, and rather due to natural recovery or due to displacement on the list, as they were never endangered.  According to Competitive Enterprise Institute Research Associate Brian Seasholes, “The ESA has failed to recover a single species, not one.”

The Columbia Climate School’s recent study claims that the ESA fails because it does not provide protection until a species population is precariously small, limiting any chance of recovery.  Eberhard writes, “small population sizes at time of listing, coupled with delayed protection and insufficient funding, continue to undermine one of the world’s strongest laws for protecting biodiversity.”   Since small populations are drastically more vulnerable to environmental, genetic, and human threats, by the time the ESA gets involved, the species in question is already doomed.

Moreover, the ESA has had issues with the declining water quality nationwide.  Clean water is very important to endangered species, as water allows for life to exist through its various properties.  Internally, the cohesion and adhesion of water helps transport water molecules around the body, and helps support bodily functions that depend on water. Externally, water helps moderate the climate of nearby environments.  For example, water’s high specific heat allows it to absorb heat generated by the sun, cooling the temperature in costal regions.  Thus, water regulates the temperate and environment that organisms in costal reasons have adapted to.  When the external temperate dips below freezing level, bodies of water do not freeze throughout, as ice floats on top of water.  The hydrogen bonds of water stop moving when frozen, and due to the spaces in between them, ice is less dense than liquid water with rapidly moving water particles, in which hydrogen bonds form and break easily.

The lack of clean water prevents these properties to happen, which worsens the habitat of already endangered species, pushing them further to extinction.  The Environmental Protection Agency has increased efforts to control water by partnering the efforts of the ESA and The Clean Water Act (CWA), they have once again had limited success.

The authors hope that “leaders in the U.S. and across the world will learn from these lessons to better protect and conserve imperiled species across the globe.”  The ESA has undoubtedly failed to protect endangered species in America.

U.S. Endangered Species Count by State

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