AP Biology class blog for discussing current research in Biology

Author: oxsydgen

Maternal Stress During Pregnancy

According to researchers at the University of Cincinnati, maternal stress during pregnancy has a harmful effect on the neurodevelopment of babies. A methyl group gets added to DNA, which is called DNA methylation. This likely plays a role in it. The findings could provide new insight into how the fetal environment potentially influences neurodevelopment, metabolism, and immunologic functions. 

DNA methylation

More than 5,500 people took part in this study, which broke down into 12 different groups. The research examines financial stress, conflict with a partner, conflict with a family member or friend, abuse, and death of a friend or relative. Plus, there is a cumulative score that combines all these categories. 

Two young people demonstrating combat

They found that mothers experienced a great amount of stress during pregnancy. There was an association with DNA methylation in the umbilical cord blood, which is an epigenetic modification in the baby’s development. They found five specific locations of DNA methylation with three different maternal stressors. The three different maternal stressors were conflict with a friend or family, abuse, and death of a close friend or relative.  

Epigenetics modifications

In AP Biology, we have learned that DNA methylation causes nucleosomes to pack tightly together, which prevents transcription factors from binding to the DNA. Gene expression is the process of turning on a gene to produce protein and RNA. 

The researchers plan to further investigate and do some functional analyses to see how the genes work and how the DNA methylation affects their expression. 


Medicine of the Future

According to researchers at Karolinska Institutet in Sweden, there are many challenges when it comes to using CRISPR gene editing as a part of medicine of the future. One challenge is how cells behave when subjected to DNA damage. 

TopBP1 Activation of ATR in DNA Damage ResponseDamage to cells activates the protein p53. The technique is less effective when p53 is activated, but a lack of p53 allows cells to grow rapidly and become cancerous. The p53 protein gene is a tumor suppressor gene. If a person inherits only one copy of the p53 gene from their parents, they are predisposed to cancer and usually develop numerous tumors, Other linked genes with mutations can have a similar effect to p53 mutations. The transient inhibition of p53 is a strategy for preventing the advancement of mutated cells. The DNA damage response can potentially be a marker in development of more precise guide RNA sequences. 


We have learned thus far in AP Biology that mutations are changes that occur in the DNA sequence of an organism or a change in a genetic sequence. Mutations can be caused by mistakes during cell division. They can be harmful, beneficial or have no effect. 

The researchers plan to further conduct clinic-centered tests in order to understand how pertinent these mechanisms are. This study is largely focused on CRISPR screening experiments on isolated cells and analysis of the DepMap database. 

Serotonin: Costs & Benefits

This study concluded that serotonin may potentially accelerate a cardiac condition known as generative mitral regurgitation. DMR is one of the most common cardiac diseases. The left atrium and left ventricle of the heart are where the mitral valve is situated. When the heart contracts, it closes tightly to stop blood from flowing back into the left atrium. DMR can therefore result in symptoms including exhaustion and shortness of breath. The heart has to work harder as a result of the decreased circulation efficiency, which over time results in lasting harm. The deterioration of the mitral valve is now untreatable. 

Serotonin is involved in many bodily processes, including mood, digestion, sleep, memory, and blood coagulation. Your brain uses serotonin as a neurotransmitter to control mood; anxiety and depression are linked to low serotonin levels. A cell receives a signal from serotonin to function appropriately when it binds to particular receptors on the surface of the cell. Serotonin is transported into the cell by a protein called the serotonin transporter (SERT or 5-HTT), where it is reabsorbed and regenerated. 


Serotonin can stay available for longer lengths of time thanks to medications known as selective serotonin reuptake inhibitors (SSRIs), which bind to the SERT and decrease serotonin reuptake. Some examples of SSRIs are medications such as fluoxetine (Prozac) and sertraline (Zoloft). 

The study assessed 100 mitral valve samples and clinical data from over 9,000 patients who had undergone valve repair or replacement surgery for DMR. In analyzing the data of these patients, Ferrari and colleagues discovered that SSRI use was linked to severe mitral regurgitation that required surgery at a younger age than in those who did not take SSRIs.

ZOLOFT (sertraline HCI) Crop

Additionally, the researchers used normal and transgenic mice lacking the SERT gene to study in vivo mouse models. They found that normal mice treated with high doses of SSRIs also had thickened mitral valves, and that mice lacking the SERT gene similarly acquired thicker mitral valves. The researchers discovered genetic variations in the 5-HTTLPR region of the SERT gene that have an impact on SERT function using genetic analysis.

One thing we have learned this far in AP Biology is that a receptor is a protein that can bind to a molecule. Different receptors cause different effects in the cell. Receptors are specialized proteins found on the surface or inside cells that are able to recognize and respond to specific chemical signals, such as hormones, neurotransmitters, and other signaling molecules. These signals can trigger a range of cellular responses, including changes in gene expression, alterations in cellular metabolism, or changes in the electrical properties of cells. Receptors are essential for many physiological processes, including sensory perception, regulation of the nervous and endocrine systems, and immune responses. There are many different types of receptors, including ion channels, G protein-coupled receptors, and enzyme-linked receptors, each with their own unique structure and function.

Androgen receptor 3-d model

I think this is very interesting considering that people did not know that SSRI use led to severe mitral regurgitation. People had to have surgery at young age to fix this. Many individuals would not have had to go through with a medical procedure if they knew what was causing this. 

Do Vaccines Really Prevent Viruses?

Researchers from the University of Birmingham have shown that T cell immunity is coping with mutations that have increased within COVID-19 variants. Researchers tested CD4+ T cells at the beginning of the pandemic and found that a few of the T cells were able to recognize the epitopes in the Omicron variant. As SARS-CoV-2 continues to mutate, T-cell recognition of epitopes could decrease, causing a decline in the overall protection of the immune system. Although most people have a diversified T-cell response against the virus, some are less effective against Omicron specifically.

Vaccines developed at the beginning of the pandemic help to provide strong protection against severe hospitalization and death. But COVID-19 and SARS-CoV-2 continue to mutate. These mutations alter the epitope, which the virus uses to enter. It helps the virus to dodge the immune system’s attack. Current vaccines help the creation of antibodies and immune cells that recognize the protein. 

Vials containing the Moderna COVID-19 vaccine sit on a table in preparation for vaccinations at Kadena Air Base, Japan, Jan. 4, 2021. As part of the DoD strategy for prioritizing, distributing and administering the COVID-19 vaccine, those providing direct medical care and emergency services will be prioritized to receive the vaccine at units based in Japan, including Kadena AB. (U.S. Air Force photo by Airman 1st Class Anna Nolte)

One thing we have learned thus far in AP Biology class is that T Helper Cells stimulate other T cells to divide and create two types of cells. T Memory Cells are long-lived cells to prevent reinfection, and T Killer Cells or Cytotoxic T Cells kill infected or cancerous cells. 

It is very interesting for us to be able to understand how vaccines work to help us. Current mRNA vaccines produce some T cells that recognize multiple variants. This may help to protect against severe disease with the Omicron variant. Hopefully, with continued research, they will be able to make another vaccine that can specifically enhance this T-cell response. 

Fight or Flight? A stroll down memory lane…

Everyone handles fear differently. Have you ever wondered why some people are fearless, while others are afraid of their own shadows? Fear is a natural human emotion that arises when we feel threatened or harmed. Fear can be rational or irrational. In some cases, like post-traumatic stress disorder (PTSD) or anxiety-related disorders, fear responses can be uncontrolled or exaggerated. Researchers have been trying to figure out what specifically triggers fear and how it turns into a long-term memory. 

Depression - a lonely alcoholic in fear covers his face with his hands

This study from researchers at Linköping University investigated the biological mechanisms that impact fear-related memories in the brain. They used rats and discovered potentially groundbreaking data behind anxiety-related disorders and alcohol dependence. For those of us who need a quick lesson on the brain, the amygdala regulates emotions and is activated by endangerment or threats. The nerve cells connect the frontal lobe to the amygdala. Interestingly, the research found that these connections are changed in people with anxiety-related disorders. 


Specifically, they investigated a protein known as PRDM2. This protein encodes a zinc finger protein that can bind to different types of proteins and receptors. Levels of PRDM2 seem to play an important role in exaggerated stress responses and are also lower in those who are alcohol-dependent. It is common for anxiety-related disorders and alcohol dependency to be present at the same time, and the researchers suspect that this is caused by the protein. 


A little more review on the science of the brain is needed before we continue.  The formation of memories are complex and may be connected to our fear responses.  Consolidation is when new memories are formed and preserved into long-term memories. Increased activity between the frontal lobes and amygdala increases learned fear reactions. The decrease in PRDM2 increases the consolidation of fear-related memories. 

Mental Health - The Noun Project

The research suggests that patients with anxiety-related disorders may benefit from treatments that weaken fear memories. Researchers have discovered a way to down-regulate PRDM2, but do not have a way of increasing it, yet. This mechanism could be a part of the explanation as to why individuals have a greater susceptibility to anxiety-related disorders and why these disorders are commonly associated with alcohol dependency. 

Protein PRDM2 PDB 2JV0

One thing we have learned thus far in AP Biology class is that ribosomes are protein factories located free in the cytosol or bound to the rough endoplasmic reticulum or nuclear envelope. Within the rough endoplasmic reticulum, proteins are produced to either be secreted outside the cell, membrane-embedded proteins, or proteins to go inside organelles. 


Although they have not discovered a way to increase PRDM2, it is very interesting for us to be able to understand how our fear memories turn into long-term memories and what causes individuals to be more vulnerable to mental health disorders. Hopefully, with the continued research on the biological mechanism that may cause fear, we can reverse engineer the cause and create new innovative medicines to treat and, perhaps, completely cure them. 

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