AP Biology class blog for discussing current research in Biology

Author: addna

Environmental Cues Can Trigger Planned Movement and Advance Studies of Motor Disorders

A group of scientists from different universities, including Dr. Hidehiko Inagaki, Dr. Susu Chen, and Dr. Karel Svoboda, came together to understand how cues in our environment can trigger planned movement. Neurons in the human brain are active with diverse patterns and timing. The Motor cortex is responsible for the control of movement. The patterns of the motor cortex differ in the phases of movement. The transitions between these phases is a critical part of movement. The brain areas controlling these transitions were a mystery.

To identify the parts of the brain controlling these transitions the group of scientists performed their research on mice.They recorded the activity of neurons in a mouse’s brain when doing a triggered movement task. Researchers found brain activity taking place directly after the go cue and between the stages of movement. This brain activity came from a circuit of neurons in the midbrain, thalamus, and cortex. To determine whether this circuit was a conductor or not the scientists used optogenetics. Through the use of optogenetics Dr. Inagaki and his colleagues were able to identify a neural circuit critical for triggering movement in response to environmental cues. Dr Inagaki says that “We have found a circuit that can change the activity of the motor cortex from motor planning to execution at the appropriate time. This gives us insight into how the brain orchestrates neuronal activity to produce complex behavior.


Not only is this important for the use of knowing more about the brain but it also helps to advance studies of motor disorders, such as Parkinson’s disease. By adding environmental cues to trigger movements it could drastically change the mobility of patients.

In Ap Biology class we learned about cell communication. Neurons communicate with each other by releasing specific molecules in the gap between them, called the synapses. The sending neuron passes on messages through neurotransmitters that are picked up by the receptors of the receiving neuron.

CRISPR corrects genetic diseases in mice!

Researchers at Duke University have shown that a single systemic treatment using CRISPR genome editing can safely correct Duchenne muscular dystrophy (DMD) in mice for over a year. In 2016 the first successful use for CRISPR to treat an animal model of a genetic disease was published by, Charles Gersbach, the Professor of Biomedical Engineering at Duke. The strategy used by Gersbach can potentially be used for human therapy.


Since 2009, Gersbach has been working on finding a genetic treatment for DMD and his lab was one of the firsts to focus on CRISPR, which is a defense system that slices apart the DNA of invading viruses.The goal was to cut out the dystrophy exons around the mutation and then let the body naturally repair the DNA and stitch it back together to create a shortened dystrophy gene. After eight weeks it was observed in the mice used for the experiment that functional dystrophin was restored and muscle strength increased but the long term effects of the treatment had not been explored.


The new goal of Gersbachs study was to figure out these long term effects. To determine this, doctor Christopher Nelson gave both adult and newborn mice with the dystrophy gene a dose of CRISPR. The mice were monitored over the year to see what kind of genetic alterations were made as well as any immune responses. There were no results of toxicity in any of the mice. Although this is a positive result Gersbach and Nelson know that a mouse immune system can function differently than a human immune system which brings further questions of reliability of CRISPR in humans to the table.


In my AP biology class we recently learned about gene expression. CRISPR systems have been engineered to control gene expression in bacteria. CRISPR is used to target precise parts of DNA which could help to correct abnormalities that cause diseases.

Antitoxin Mechanism Saves Us From Virus Attacks!

Researchers in Lund have recently discovered an antitoxin mechanism that may be able to protect bacteria against virus attacks by neutralizing hundreds of toxins. Understanding this antitoxin mechanism, named the Panacea, could be the next step to the future success of phage therapy, a treatment for antibiotic resistant infections.

These toxin-antitoxin mechanisms are a kind of on-off switch in bacterial DNA genomes. They are found to attack bacteriophages to defend bacteria.This activation of toxins allows bacteria to “lockdown” and limit growth and spreading of a virus. In order for Phage therapy to be successful in the future, it is important to understand these mechanisms in great depth. The goal of Phage therapy is to use viruses to treat bacterial infections. A toxin dramatically inhibits bacterial growth and an adjacent gene encoding an antitoxin counteracts the toxic effect. Although toxin-antitoxin pairs have been associated with new toxins or antitoxins before, the ability of the Panacea is unprecedented.

Phage therapy

As research continues on toxin-antitoxin systems and phage therapy it is clear that what we know is just the tip of the iceberg. As bacteria increasingly become resistant to antibiotics, other approaches are needed to help eliminate infections. The next steps of this research is to continue deepening the understanding of the Panacea and finding toxin-antitoxin systems on a universal scale.

In AP biology class we learned about inhibitors. An inhibitor is something that slows down or prevents a particular reaction or process. A toxin inhibits bacteria from growing and reproducing so the antitoxin can act against the virus that has already spread.

Gene Variant Saves Humans from Starvation!

A recent study in Science Advances, suggests that a variant of the growth hormone receptor gene protected humans against starvation millions of years ago. The gene protected us by limiting individuals body size during the scarcity of food. The variant, GHRd3, has been linked to characteristics such as small birth size, early sexual maturity, and other characteristics that would help a human when recourses are scarce.

The variant suddenly plummeted in number around 40,000 years ago but many people still carry it today. In order to dig deeper into what role the variant played in human evolution, Omer Gokcumen, the study’s lead author, turned mice into representations of humans millions of years ago. His team deleted part of the mice’s growth hormone receptor genes so they resembled the GHRd3 Variant.The mice all lived in the same habitat, were fed the same amount, and drank the same amount of water. The mice with the variant grew up to be smaller than their unmodified equivalents. Gokcumens’ team also found that out of 176 children today that have suffered from malnutrition, symptoms were much less severe in children with the GHRd3 variant.

Protein GH1 PDB 1a22

Researchers continue to wonder why GHRd3 has persisted for so long but these findings could help to explain! It is possible that changes in available resources could have impacted the benefits of different variants.

In my AP Biology class, we learned about receptors. Reception is the first stage of Cell signaling. It is when a signal molecule binds to a receptor protein, causing some kind of conformational change in the receptor. Growth hormone receptors are Receptor Tyrosine Kinases which means they dimerize when signaling molecules bind. The tyrosine phosphate regions are phosphorylated by ATP and trigger a relay pathway sending signals through the cell for a response.

A New Way Of Detecting the COVID-19 Virus

In a study conceived by Mayo Clinic investigators it was found that Artificial Intelligence may offer a new way of detecting if a person has contracted Covid-19. Researchers found that the Covid-19 virus creates small electrical changes in the heart that Artificial Intelligence (AI) can detect and be used for a new form of a rapid, reliable test. Since Covid-19 has a 10-14 day incubation period, symptoms take long periods of time to show up. Once patients do show symptoms it is hard to access a reliable Covid test with fast results. An Artificial Intelligence enhanced EKG is a rapid and cost effective alternative for Covid testing.

Covid - 19 virus

This study was done on a racially diverse population of volunteers from 14 different countries. Patients selected had previous EKG data from when they were diagnosed with Covid-19. This data was compared with the EKG data of patients not infected by Covid-19. AI was then trained to detect the subtle changes in the heart by more than 26,000 EKG’s and tested on 7,800 EKG’s that were not previously used. The prevalence of Covid-19 was about 33% and the accuracy of the negative predictive value of the AI was about 99.2%.

For any form of Covid test, accuracy is the most important value. The study shows the consistency of biological signals in the EKG and the Covid-19 infection. To confirm that Artificial Intelligence will be a helpful factor in our fight against the pandemic, this study needs to be tested on asymptomatic people.

In AP biology class this year, my class has learned about sending signals between cells. A heartbeat happens when the SA node (pacemaker of the heart) sends out an electrical impulse.The upper chambers of the heart contract and the AV node sends an impulse into the ventricles.The lower heart chambers then contract and the cycle starts over again.

Smelling Saves Lives!

Using a Novel technique, researchers at Karolinska Institutet in Sweden have been studying the brain and how our central nervous system judges a smell to represent danger. Our brain can distinguish between millions of different smells because of the olfactory organ. The olfactory organ is located in the walls of the upper part of our nasal cavity. Most of these smells are associated with a threat to our body’s health. After inhaling an odor it takes between 100 and 150 milliseconds to reach the brain. The detection and reaction of a smell has always been an important factor in all mammals’ survival. The researchers at Karolinska Institutet’s study has proven that negative smells are associated with unrest and are processed earlier in the brain than positive smells.Anatomy and physiology of animals Olfactory organ the sense of smell

Unpleasant smells trigger a physical avoidance response. The avoidance response has always been seen as a conscious cognitive process but recent research has proven that it is actually an unconscious and rapid process.

For a long time it has been a mystery as to which mechanisms in the brain are involved in the process of associating an unpleasant smell with danger and causing avoidance behavior in humans.The researchers at Karolinska Institutet have come up with a process in which you can measure signals from the olfactory bulb. The Olfactory bulb transmits signals to the part of the brain that controls avoidance behavior. Avoidance behavior can be described by a number of patterns, one of those patterns being a pattern of protective reflexes.

Three experiments were conducted where participants were asked to give their opinions on six different smells. The associate professor at the Department of Clinical Neuroscience shares that “the results suggest that our sense of smell is important to our ability to detect dangers in our vicinity, and much of this ability is more unconscious than our response to danger mediated by our senses of vision and hearing.” 

In AP Biology class, we learned about protein receptors. Smelling relies on protein receptors recognizing specific ligands. Humans are able to distinguish thousands of different compounds by smell. The shape of a molecule is most responsible for its smell rather than its physical properties. Thus, the smell relies on the interaction with a binding surface, usually, a protein receptor. 

It is so interesting how our bodies can distinguish the smallest differences in molecules. These differences can change the smell of something completely. These smells also help to determine our emotions. Smelling something bad can make us uneasy or feel unsafe while smelling something good can bring us joy. Can you think of a scenario where a smell made you feel unsafe?

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