AP Biology class blog for discussing current research in Biology

Author: lagoon1

Pigs Leading The Way In Organ Transplants

Bio Threats- FDA's A-Team (6355) (9806964753)

Scientist looking at pig cells

Imagine waiting for a phone call that could save your life, but you never get the call. This is a reality for many patients that are on an organ transplant list. Recently scientists have found a way to make it possible for a patient to get a transplant without waiting for the rest of their lives. Richard Slayman is a 62 year old man from Massachusetts who, went through xenotransplantation, received the first pig kidney transplant while still alive. How would you feel about receiving an organ from a pig?

In recent years scientists have been genetically engineering pigs for human organs to address the lack of human organs available for transplant surgeries. Many of past transplants have been unsuccessful. Some of the transplants included “hooking a kidney up to a brain-dead organ donor’s body, and another involved performing a double-kidney transplant in a brain-dead patient. In addition, in 2022, a man underwent the first pig-heart transplant but died shortly thereafter”

Richard Slayman faced type 2 diabetes and high blood pressure which lead him to seven years of dialysis before his first human kidney transplant in 2018. This transplanted organ began to fail five years later which pushed him back to dialysis in 2023. This lead Richard to receiving the kidney transplant. The wait for another human transplant would have been too long. Richard was presented with an opportunity to get a transplant using a kidney from a genetically engineered pig. What would you do wait or get the transplant? The genetically engineered pig was developed by eGenesis using CRISPR technology. The total number of gene edits in the DNA was 69.

Dr. Ehtuish Performing An Organ Transplant.

Doctors performing an organ transplant

The scientists removed three genes responsible for creating carbohydrates that trigger human immune responses. They also added seven human genes to prevent potential immune system rejections, and they deactivated certain viral DNA sequences known as endogenous retroviruses that could pose risks to human health. These adjustments were done to ensure the organs are safe for transplantation into the human body.

Richard Slaymans pig transplant has been a huge success. So are pigs going to lead the way in organ transplants? So far it seems to be the case. Richard Slayman in the past few days has left the hospital. Now the doctors need to continue to check in with Richard to make sure all is going well. This is very important because it is common for the transplanted organ to be rejected and also possible infection. To prevent this the doctors have to give the patient a perfect balance of immunosuppressive drugs. “too low a dose can lead to rejection, while too much can make a patient vulnerable to infection”

In AP Bio we learn about the importance of DNA and RNA function and the manipulation of it. DNA determines the production of RNA, and the RNA then allows for the production of proteins that carry out all the functions we need it to. CRISPR technology uses guide RNA, which is specifically made to match particular DNA sequences. This allows CRISPR to harness a cell’s mechanisms to precisely target and alter genetic data. This process demonstrates roles of DNA and RNA in genetic expression and regulation, and being able to do this will allow for a lot more possibilities. This topic also relates through the impact of the immune system when the organ transplant happens. The immune system plays a role in distinguishing between self and non-self cells. When a foreign organ is transplanted, the recipient’s immune system may recognize it as a threat. This leads to organ rejection. This immune response is lead by T cells that identify mismatched human leukocyte antigens on the donor organ. To prevent rejection, patients will undergo immunosuppressive therapy, which will lower the immune system’s activity but this also increases susceptibility to infections and other diseases. What do you think about the process of organ transplants. Is it efficient the way it is or will new science make it more efficient with the help of animal organs?

The Ant Who Stole the Lion’s Dinner

In the African savanna ants are changing the diet of lions, but how? The introduction of an invasive ant has disrupted what seemed to be an insignificant mutual relationship within the intricate web of life in the savanna.

The invaders of the savannah are the big headed ants, and the native ants are the acacia ants. The big headed ants overpower and kill of the native ants. The acacia ants protect the whistling thorn trees from the elephants. The ants protect these trees by biting the elephant when it gets close. The acacia ants biting the elephant prevent the elephant from  uprooting the tree. When the elephants do this there is less cover for the lions to hunt for their preferred meal, the zebra. As a consequence, lions shift their focus to hunting buffalo instead. How would you feel if you were no longer to have your favorite food?

African Sunrise, Amboseli National Park (30385097358)

Elephants in African Ecosystem

The relationship between the acacia ants and the whistling thorn tree is mutualistic, where both species benefit from the interaction. Imagine it as you are each other’s best friends. The tree provides shelter and sustenance to the ants through specialized structures called domatia and extrafloral nectaries, while the ants protect the tree from herbivores like the elephant, as well as competing plants by aggressively defending it against potential threats.

Acacia drepanolobium-- Whistling Thorn (25396927222)

Whistling Thorn Tree

Scientists tracked the activity and kills of lionesses in a conservancy in kenya, while also conducting experiments on big-headed ants and those under the influence of the native ants. The invasion of big-headed ants, believed to have been introduced from imported produce.

The researchers did not have the budget to use drones or satellite imagery. So the researchers measured tree cover by tracking lions and the visibility near their kills. The results stated that areas with big-headed ants exhibited significantly higher visibility. This allows for lions to see their prey better but also the prey can see the lions allowing them to escape.

“Over the three years of the study, zebra dinners decreased from 67 percent to 42 percent of lion kills” “Buffalo kills increased from zero to 42 percent of kills over the study period” By lions switching to buffalo is more risky for the lion since the  buffalo are more likely to be injure the lion over the zebra.

This study in relation to AP Bio relates to the topic of ecology. If you had to guess what one of the most important things to take away form this study is? You are right if you said the disruption of mutualism can have cascading effects on other species in a community. The ants were able to change the food web of the whole ecosystem. It is important to keep the food web in balance because an imbalance will create major effects on the populations of some species. As seen in the study, the population of zebras in crease while the population of buffalo and lions decrease. Symbiotic pairs are able to keep ecosystems in check when one organism has the other to rely on. The loss of one partner could trigger cascading effects, reshaping entire ecosystems. The study of the lions change in diet offers valuable insights into the delicate balance of nature.

Blood Clotting Proteins Predicting Signs of Long COVID

Many individuals experience sickness after they have already been cured of COVID. This is called long COVID, symptoms include cognitive problems also referred to as brain fog. Having these issues leads to a decreases in memory and concentration making it harder to function in everyday life. Now imagine still feeling sick even though you really are not sick with the virus, not a good feeling. These symptoms are now believed to come from blood clots triggered by the virus. The blood clots leave behind proteins in the blood so researchers are able to find and diagnosis patients who think they have symptoms after they have had COVID.

A study by Nature Medicine found that blood tests could point signs of long COVID. 15 % of people who contracted the virus develop long COVID symptoms. Symptoms of long COVID could last for months and possibly even years. This condition is difficult to treat and diagnose due to the wide range of symptoms it causes. These symptoms include brain fog, chest pain, dizziness, and joint pains. We all know what it is like having these pains so are able to understand how difficult it is to go through your everyday life with long COVID. Scientists are still trying to figure out if the virus stick around in the body or if it leads to other reaction, like having an autoimmune response.

The lead researcher Maxime Taquet, along with others from the University of Oxford, conducted an experiment in the United Kingdom. They tracked over 1,800 hospitalized COVID patients between the years 2020 and 2021. After six and twelve months the scientists conducted cognitive assessments and took blood samples. These are tests you still want to do good on. The blood tests revealed that the patients dealing with brain fog had specific proteins in their blood, proteins that we all have in common. The first protein is called D-dimer, which is present when blood clots breakdown. The patients with this protein did not do poorly on their cognitive tests so their memory and concentration is in tact. On the other hand these patients experience shortness of breath. This could be a sign the blood clots are taking place in the lungs causing the brain to not get enough oxygen levels. The second protein found in some patients is called fibrinogen. This protein is synthesized in the liver and stops bleeding. The patients who had this protein complained about memory impairment and sadly they also did not do well on the cognitive test.


D-dimer Formation

Another test was conducted, analyzing around 50,000 people in the United States looking for D-dimer and fibrinogen. Higher D-dimer levels were only found in people who previously had COVID, while high levels of fibrinogen correlated with brain fog whether or not a person previously had COVID. This indicates that fibrinogen is involved in other cognitive conditions.

Human fibrinogen structural scheme

Human Fibrinogen

Although scientists know there is a relationship between blood clots and long COVID, there still needs to be more research done. Even the blood in your body could help research! Research is currently being done on how the SARS-CoV 2 spike protein affects the fibrinogen protein, and research treatments for clot dissolving medications. This is challenging though since the symptoms and diagnosis of long COVID is still difficult to spot. Scientist will continue studying blood samples and patients suffering from long COVID to better understand the sickness.

The research being conducted can be related to the AP Bio class about the role of the immune system is response to the virus. The immune system is very responsive when COVID is introduced to the body and when it is gone in long COVID patients. A study was conducted and it was found that participants with long COVID had higher levels of non-conventional monocytes and activated B lymphocytes. They had lower levels of type 1 conventional dendritic cells and central memory T cells. The B cells are responsible for attacking pathogens that are free floating, and T cells are responsible for attacking pathogens in infected cells. The dendritic cells break down pathogens and present the antigen on its surface for it to then be found by the T helper cells to pass on the information. These participants’ antibody responses is also stronger against the SARS-CoV-2 spike protein. Those who do not have long COVID do not have responses as strong. Long COVID participants also are more susceptible to other diseases. Other disease, once in the body can trigger the body to have more and worse symptoms. All these specific parts of are immune system all work together in all of our bodies to form the way we each combat infections. We should all be grateful for processes our bodies go through to help us get through our everyday lives.

Sea Turtles Survival in The Salty Seas

Water makes up 71% of our planet while only around 3.5% of the total water on. Earth is fresh. While there is plenty of water around, many animals can’t even drink it. For humans, consuming salt water disrupts cellular processes. Cells try to balance osmotic pressure, and end up losing more water, leading to dehydration. Our kidneys also work to filter out the excess salts, but the high rapid intake of seawater overwhelms our body’s ability to eliminate it. However, marine animals, like the sea turtle, have evolved to live in salty environments. Although sea turtles can process and get rid of the salt from their bodies, they are not too different from humans when it comes to the intake of salt water. You may think how is a sea turtle similar to us? Well Sea turtles have less salt inside their bodies than the ocean around them, and their kidneys can’t make saltier urine than their blood. In order to survive they need less salt in their bodies than their surroundings. The turtles are able to keep the salt from going through its skin because their skin is so tough. Some marine animals are able to regulate their water intake through the food they eat, like in the case of whales, but this does not work for the sea turtle. The main food source for many sea turtles are jellyfish. If you think about the jellyfish, they really dont have much to them. If you had to guess that sea turtles have to eat a lot of jellyfish to get the energy they need you would be right. Jellyfish are 96% water, and 4% salt, which makes them salty just like the ocean. Less than 1% of the jellyfish is used for food. This causes the sea turtle to take in a lot of salt along with its meal. Imagine having more salt than food on your plate! How would you handle the intake of all that salt?

Chelonia mydas and bubbles

Sea turtles use salt glands to shed out the salt they intake. The salt glands take up a large part of the head region, primarily around its eyes. The glands transport the salt from the turtle’s bloodstream and concentrate it into a salty solution, which is then excreted through the turtle’s tear ducts. Specifically the leatherback sea turtle cries around 8 liters (2 gallons) of tears every hour. Yes, it sounds sad, but sea turtles cry out salt everyday. This process is very important in maintaining sea turtles internal salt balance and allows them to survive in salty environments.

In our AP Biology class, we learned about osmosis which is, the movement of water across a permeable membrane to equalize solute concentrations. The process of a  turtle’s regulation of its bodys salt concentration is related to the topic of osmosis. In the case of sea turtles, their bodies must manage the osmotic challenge of living in a salty ocean environment. The process of the turtle using its salt glands involves the movement of water. This process involves moving water to dilute the excess salt, and is a form of osmosis that helps the turtles maintain their internal salt balance despite the high-salt surroundings. As we learned, animals can not have salt water surrounding their cells because it will cause the cells to become severely hypertonic, meaning the cell will completely shrivel up since the water went from a high concentration of water inside the cell to the low concentration of water surrounding it.

Osmosis diagram

Process of osmosis: water going from high to low concentration


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