BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: development

Intermediate Host of COVID-19 Found to be Pangolins

COVID-19 had intermediate animal hosts before beginning to infect humans. It is not uncommon for viruses and illnesses to have animal hosts that have the ability to transmit it to other organisms, one such example being mosquitoes and various illnesses such as malaria and the West Nile virus. It has been proven that bats are carrier of SARS-CoV-2, but scientists have been trying to discover how exactly it got from bats to humans. This knowledge matters because understanding where the virus originated and how it came to infect humans could prove crucial to future treatment and control.

It was originally suggested that snakes were the intermediate host due to a genome study; however, it had a lot of scientific criticism for a few reasons, one such being the fact that the coronavirus has only been known to infect mammals and birds. Meanwhile, another unrelated study comparing the spike proteins to that of HIV-1, discovered a few unexpected similarities. Due to the rise of conspiracy theories and rumors, a scientist by the name of Yang Zhang, along with some colleagues, decided to conduct a more in-depth study on SARS-CoV-2 sequences.

Yang Zhang and his colleagues uncovered the error in the analysis that claimed snakes were the intermediate host. Additionally, they analyzed and compared DNA and protein sequences from pangolin tissues in order to try to find those similar to SARS-CoV-2. They were able to identify protein sequences that were 91% identical to those found in the human virus’ proteins. The spike protein found in pangolins only had 5 differences in the amino acids as compared to the 19 differences in the bat viral proteins which is further evidence that pangolins are the intermediate host. However, researchers say that it is possible for other intermediate hosts to exist.

A pangolin, now suspected to be an intermediate host of the coronavirus

So how does an illness transfer from animals to humans? One belief is that rapid mutation is the main factor that allows viruses to adapt to overcome a new hosts barriers and immunological defenses. Another proposed theory is host similarity as explained by Gary McCracken, a professor at the University of Tennessee. They tested this theory by analyzing hundreds of rabies viruses in various species of bats. They found that the more genetically similar species of bats had these cross-species viruses.

As more tests have been conducted, it has been found that some animals, other than bats and pangolins, are also able to be infected with the coronavirus. João Rodriguez from Stanford University and some colleagues used computers to simulate and investigate how the spike protein interacts with different animal cells ACE2 receptors. The better the viral “key” fit into the receptor “lock”, the more susceptible that species was to SARS-CoV-2. Therefore, by applying this knowledge (as well as McCracken’s theory) to other situations, it would make sense that humans could be infected by a cross-species virus, particularly from other mammals.

This connects to what we learned in class about receptors and cell signaling. ACE2 receptors are found on cells throughout the body, most notably in this case, in the lungs. ACE2 receptors help regulate blood pressure, wound healing, and inflammation. Once a message (a signaling molecule or such) is received by the receptor, cell signaling moves into the next stage of transduction which ultimately produces a response. Therefore when something (in this case COVID-19) interferes, the proper signaling becomes changed or altered leading to the symptoms we have come to recognize as COVID-19.

Science Proven Fact: The Older Sibling is the Best

As it is very clear to see, I am the alpha sibling. I am better than my brother in all ways. I always knew this, but now I can prove it with science!

Exhibit A: My parents just love me the most.

The main difference in the upbringing of an older sibling and a younger sibling is the quality of parental investment. With their first child, parents (on average) put a greater effort into reading with their child, playing music/listening to music, or taking them places. However, with next child, parents decrease the level of cognitive stimulation. The Home Observation Measure of the Environment, used to assess the quality of a child’s learning environment, shows that the first-born child has higher quality cognitive stimulation from the parents compared to the younger siblings.

Zach Chisolm, https://www.flickr.com/photos/artifishall/3948899806

 

Exhibit B: The Birth Order Effect

The Birth Order Effect is when earlier-born children make higher wages and have better occupations as adults than their younger siblings. The more years between the birth of the first child and the birth of the second child, the more benefit to the older sibling. This is because as parents have more children, they need to divide up their time and resources among more offspring. Although as time passes, parents generally make more money and gain experience, their attention must be divided among all of their children.

Differences in the social and physical development of children as a result of the Birth Order Effect can arise even before the age of three. These differences become more apparent as the children grow older, and can be seen in verbal, reading, math, and comprehension tests.

 

Exhibit C: Oprah is an older sibling. You get a car!

 

Disclaimer: Regardless of birth order, parents generally put in the same amount of effort for each child to ensure appropriate emotional development. So don’t worry! There is hope for my brother and all of the younger siblings out there!

 

 

 

 

Epigenetics and Brain Development

Pre-natal human brain development helps determine many major qualities a person may have in life. Research at the University of Exeter found that a type of Epigenetics, DNA methylation, helps us understand the differences between male and female brains. They studied that this type of gene regulation in pre-natal brain development may help us grasp more information about “sex differences in behavior, brain function, and disease.”

In the womb, as organs are developing, the brain has extreme plasticity. Professor Jonathan Mill of the University of Exeter explains how it is extremely vulnerable to changes because the brain is creating the structures that “control neurobiological function across life.” The research consisted of measuring genomic patterns of DNA methylation in the womb between 23 and 184 days after conception. DNA methylation is a chemical modification to one of the 4 nitrogen bases that helps create one’s unique genetic code. By studying the DNA methylation, or turning on of selected genes, in the pre-natal period when the brain is being developed, it helps scientists understand the susceptibility of different neurological diseases based on one’s sex. Helen Spiers from King’s College London explains how male and females have unique differences with certain disorders, such as Autism. She says how “autism affects five males to every female.”

The molecular switches that regulate genes were found to be gender specific. They also help differentiate brain cells from other cells in the body. This research gained traction in understanding the unique qualities of the DNA “blueprint” of males and females in their developing stages. The genetic switches that are turned on in pre-natal development for each gender are unique, and a deep topic of study. By doing so, in the future, scientists can research deeper into neurological diseases that are unique to males or females, and how they may be created in the womb.

 

Original Article: http://www.sciencedaily.com/releases/2015/02/150203190223.htm

Link to picture:

http://commons.wikimedia.org/wiki/File:Brain_01.jpg#mediaviewer/File:Brain_01.jpgBrain_01

Powered by WordPress & Theme by Anders Norén

Skip to toolbar