AP Biology class blog for discussing current research in Biology

Author: sarahtonin

HIV Adapts to CRISPR-Cas9 Treatment

There has been an abundance of research using CRISPR/Cas9 gene editing to search for a cure for HIV. The HIV virus enters immune cells and uses the host cell’s method of replication to replicate the viral genome. With CRISPR/Cas9, specific mutations can be introduced in order to make it more challenging for the HIV virus to enter Helper T-Cells. Guided by specific strands of RNA, the Cas9 enzyme can cut a particular piece of the viral genome out, rendering it useless.

When a team of researchers at McGill University attempted to use the CRISPR method to disable the HIV viral genome, they found a major roadblock. Two weeks after the CRISPR/Cas9 treatment, the host cells appeared to be creating copies of the virus. This may be attributed to an error in the enzymes that copy the viral DNA, causing a change in the genome, and a mutation that allows it to evade the CRISPR treatment. However, the McGill researchers believe that this mutation was a result of the CRISPR treatment itself.

After DNA is cut by the Cas9 enzyme, the host cell usually attempts to repair the damage. Occasionally, this results in the addition or deletion of a few nitrogenous bases. While these changes usually result in the inactivation of the cut gene, sometimes they don’t. The active cut DNA is no longer recognized by the machinery used to prevent HIV infection of the cell, and the mutated viral genome is resistant to the usual methods of disablement.

More researchers at the University of Amsterdam had similar results in their research. While it is not that surprising that HIV can overcome the CRISPR/Cas9 gene editing at some point, the leader of the research (Atze Das) said “What is surprising is the speed- how fast it goes”.

If CRISPR was used at the same time as HIV-attacking drugs (inhibitors of protease, reverse transcriptase, and integrase), perhaps the mutations would be less  detrimental. This roadblock does not mean that a CRISPR cure for HIV is impossible, but it does make it far more challenging to overcome.

Bees Can Coach Soccer

Even a bee is better at playing soccer than I am. Ecologist Olli Loukola of Queen Mary University of London and his team have taught a number of bumblebees (Bombus Terrestris) to move a wooden ball to a specific point to be rewarded with food: AKA, Bee soccer (boccer?). The scientists had a number of bees in the stands, watching and cheering on the pro soccer players. After watching three intense games, the bees that had originally only attended the pro soccer games were put into the field. It’s a rags to riches tale of a bee that once only dreamed of playing soccer getting a chance to make it pro. Under pressure, the novice bees scored goals nearly every time, truly proving themselves to be professional bee soccer league material. However, bees that did not watch the soccer games beforehand only scored 30% of the time.

Graham Wise,

While this seems like simply a fun spin off of the bee movie, it was actually a productive use of the researchers time! The fact that the bees were able to learn how to perform a task shows that they have the ability to pick up on social cues. While it took a while for the researchers to teach the initial pro bee soccer players, the second group learned how to play much faster just by watching other bees perform the task.

In a second type of bee soccer, the researchers put three balls in front of the bees. Two of them were glued down to the table, and the third (which was farthest from the goal) was free to roll. While the untrained bees watched, the coach bees were only able to score using the third ball. However, when three balls that were free to roll were presented to the untrained bees, nearly all of them moved the closest ball to the goal, rather than the farthest one that they had seen the instructors use. This proves that the bees were able to actually think about their actions, rather than just imitate the actions of the bees before them. We may see bee olympics in the near future. Or they might take over the world. Be(e) prepared for both.

Mouse Gut Research Could Save Your Brain

A new study in mice published by Nature Magazine suggests that a specific microbial balance results in a reduction of brain damage after a stroke. The severity of a stroke is determined by two types of intestinal cells: Regulatory T Cells and Gamma Delta T Cells. Regulatory T cells have a helpful inflammatory effect. However, Gamma Delta T Cells make a cytokine which results in harmful post-stroke inflammation.

Researchers at Weill Cornell Medical College and Memorial Sloan Kettering Cancer Center studied two different groups of mice in order to learn if gut cells could be altered in order to reduce stroke severity. One group of mice had gut bacteria that was unaffected by antibiotics, while the other group of mice’s gut bacteria was extremely vulnerable to antibiotics. The group of mice that was vulnerable to antibiotics had a higher ratio of good Regulatory T Cells to harmful Delta T Cells.

House mouse.jpg

The researchers then induced strokes in all of the mice, and the brain damage was 60% less devastating in the mice vulnerable to antibiotics than the other group. In order to ensure that the difference in stroke severity was solely as a result of the gut bacteria, the researchers took the feces of the mice with reduced stroke severity, and transplanted it into new mice. Those new mice also exhibited a resistance to brain damage, confirming the belief that the gut bacteria was responsible for the change.

These new findings in the research of mice may be able to benefit humans in the future. Antibiotics or a specific diet may be able to reduce the effect of stroke on the brain. However, the gut microbiome of a mouse is vastly different than the gut microbiome of a human, so it may be a while before new treatments are discovered.

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,


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!





Tardigrades: the Superheroes of Biology

What is a Tardigrade?

Tardigrades are microscopic caterpillar-like creatures, sometimes called water bears, that are known to survive the extremes. Unfortunately, they look nothing like the Sea Bear from Spongebob, and a lot more like Rufus the Naked Mole Rat from Kim Possible.

Tardigrade (water bear)

Tardigrades are biological superheroes, capable of withstanding near total dehydration and even space vacuums. Tardigrades do something called cryptobiosis– a state in which metabolic activities are slowed and proteins and sugars are synthesized to protect the organism’s cells. This makes it possible for Tardigrades to live in extreme environments where other life forms fail to survive, such as deserts and polar regions.

Why do we care?

Scientists recently discovered a new Tardigrade superpower: Resistance to X-Ray radiation. This survival skill is due to one of the proteins synthesized during cryptobiosis: Dsup. A molecular biologist from the University of Tokyo (Takekazu Kunieda) led an experiment in which cultures of human cells were manipulated to have similar qualities to Tardigrade cells. These new cells were able to reduce radiation damage by 40%.

These new findings open the doors for improving the resistance to radiation in humans. One day, it could be safe for people to withstand extreme radiation, temperatures, or dehydration just like the Tardigrade does. Who would have thought that such a tiny organism had the potential to solve so many problems?


Powered by WordPress & Theme by Anders Norén

Skip to toolbar