BioQuakes

AP Biology class blog for discussing current research in Biology

Author: tedigrade

CRAZY NEW COVID-19 Mutation Makes Virus Weaker Against Antibodies

As revealed in a fascinating article that details a study conducted by the University of North Carolina at Chapel Hill, a mutated form of the virus has been discovered to be much more susceptible to antibodies produced by antibody drugs. This means that it is more easily disabled by antibodies produced by drugs such as the new vaccine. However, this may not all be good news as this new strain, called D614G, is also much more transmissible. D614G originated in Europe and has quickly become the most prevalent form of the virus. According to professor of epidemiology at UNC Ralph Baric, “The virus outcompetes and outgrows the ancestral strain by about 10-fold and replicates extremely efficiently in primary nasal epithelial cells, which are a potentially important site for person-to-person transmission.” These nasal epithelial cells act as a physical barrier against any pathogens attempting to enter the body and play a significant part in the control of the innate and acquired immune response. As we learned in biology, one method of innate immune response that our bodies have is mucous that traps pathogens. The nasal epithelial cells contain cilia that act to push the mucous and the pathogen contained inside out of the body. This means that if this new virus reproduces exceptionally well within the nasal epithelial cells, then it is extremely transmissible through any expulsion of mucous by either sneezing or coughing. It is also far more capable of bypassing the barrier of the mucous and entering the body. These epithelial cells also help the innate immune system by producing various cytokines. If a virus manages to make it past the barrier defenses, the epithelial cells will secrete cytokines. These cytokines will attract a type of cell called a neutrophil that digests pathogens. This means that these nasal epithelial cells are vital to the innate immune response and having a virus strain reproduce so effectively inside of them is extremely worrying.

The researchers believe that D614G is so effective at reproducing because it increases the virus’ ability to enter cells. The D614G mutation opens a flap on the tip of one of the spikes on the side of the virus which allows it to infect cells more effectively. However, this mutation also creates a weakness in the virus. When the flap is open, it becomes much easier for antibodies to bind to the spike proteins, preventing the virus from attacking additional cells.

Two researchers from the University of Wisconsin contributed to this study by experimenting with hamsters. To test the airborne aspect of this mutation, the hamsters were placed into different cages and groups so they could not touch and inoculated with either the original strain or D614G. By day two, in the group exposed to the mutation, six out of the eight hamsters were infected with D614G. In the group of hamsters exposed to the original virus, no additional hamsters were infected by day 2. This shows that this D614G is extremely effective at being transmitted airborne. However, the mutation had the same symptoms and effects as the original virus meaning it is not more severe. The researchers have also noted that these results may not be the same in human studies. I think that this study is equal parts of good and bad news. I am glad that the most prevalent form of the virus is much easier to deal with, but it is quite terrifying that it could mutate to be so much more contagious. How do you feel about this new development? Let me know in the comments. 

Shocking Connection Between Ancient Neanderthals and COVID-19

As stated in an article that details the shocking discoveries of an investigation led by Professors Svante Pääbo and Hugo Zeberg, genetic material from our neanderthal ancestors can be linked to the development of severe COVID-19. COVID-19, as I am sure you are all aware, is the disease ravaging the world and is caused by the newly

discovered coronavirus. While most people only have mild reactions to the disease and recover relatively easily, some people with underlying conditions may have a severe reaction to the disease and require hospitalization. However, this new study indicates that certain people may be genetically predisposed to a severe COVID-19 reaction, and it all links back to our 60,000-year-old Neanderthal ancestors.

The study that discovered this connection analyzed the genetic material of 3,000 patients who had both severe and mild COVID-19. The study identified a section of the chromosome that contained the genetic material responsible for the severe COVID-19. Chromosomes are tiny structures located in the nucleus of cells and these structures hold the genetic material that determines virtually everything about the cell. This genetic material is made up of nucleic acids that — when combined into a double-strand helix by covalent bonds between the phosphate, sugar, and base groups– create DNA. The order of the bases in the chain determines the amino acid sequence. We inherit our genetic material from our parents, and chromosomes are present in pairs, with one part of the pair inherited from each parent. This means that you hold genetic information from your earliest ancestors, which could potentially include Neanderthals. Neanderthals were archaic humanoids that were eventually assimilated into the homo sapien species.  However, cross-breeding was required to absorb the Neanderthals into our species, which means that most of the people alive today have a percentage of Neanderthal DNA. If a person holds one of the thirteen variants that are present in Neanderthal DNA, they are far more likely to have severe COVID-19.

Professors Pääbo and Zeberg proved this to be true by discovering that the Neanderthal variants distinctly matched the variants associated with severe COVID-19. However, they discovered that the genetic material only originated from Neanderthals located in southern Europe. Therefore, they concluded that when the Neanderthals of southern Europe merged with present-day people 60,000 years ago, they introduced the DNA region responsible for severe cases of COVID-19. Additionally, the people who possess these Neanderthal variants today are three times more likely to have severe COVID-19. The fact that I found the most interesting is how dramatically the presence of the variants vary in different parts of the world. For example, in South Asia, 50% of the population holds the variants, but in East Asia, almost nobody has them. I also think that it is rather tragic how genetic material that has not had any effect on the world for 60,000 years is just now becoming active. What do you think about this discovery? Why do you believe Neanderthal DNA is causing these extreme cases?

 

Powered by WordPress & Theme by Anders Norén

Skip to toolbar