AP Biology class blog for discussing current research in Biology

Author: mackromolecule

Meet Your New Favorite Fruit, The Groundcherry

Groundcherries are small orange fruits that are in the same plant family as tomatoes. However, they taste nothing like tomatoes. Instead, some taste like pineapples while others have a hint of vanilla. These yummy, mysterious fruits are uncommon because farmers have not grown them in sizable numbers. This is because the berries tend to drop off the branch and onto the ground before they are ripe which makes the plant unreliable for farmers to harvest.ō-ji.jpg

These types of crops were known as “orphans” because they have some appealing traits but also come with challenges which is why farmers don’t plant them in large numbers.


However, researchers Lippman and Van Eck wanted to develop a groundcherry that eliminated those challenges by domesticating the crop using a tool called CRISPR. CRISPR allowed scientists to make changes to the plant’s genome, developing new varieties more efficiently than ever before. The researchers wanted to make the groundcherry a more manageable plant and they were able to do that by making small modifications to its genome.

By doing this, they made the groundcherry plant more compact and therefore more manageable for growers. Now, culinary experts even recommend using groundcherries in cakes, pies, spicy salsas and savory appetizers. So Lippman and Van Eck really did help the groundcherry to become the next specialty crop!



Why Too Much Viagra Messes Up Your Vision.


Sildenafil is the active ingredient in Viagra and too much of it may be toxic for the cells in your eyes. According to a new report, a man in Massachusetts developed vision loss after consuming a whole bottle of Viagra. It was a 30-milliliter bottle of liquid sildenafil and contained 750 milligrams of erectile dysfunction drug. After that he began having eye problems. The man visited the doctor after two months and described seeing a ring or “doughnut” shape in his vision.

The man ended up having problems with his retinal cells. Retinal cells are light sensitive cells at the back of the eye that convert light into electrical signals that are then sent to the brain. There is no treatment for the condition and it is unclear if the man’s vision ever improved.

So how does sildenafil cause problems in eye cells? It is known to inhibit an enzyme called phosphodiesterase type 6. In high doses this inhibition causes the buildup of a molecule that is toxic to retinal cells.

Some people have reported eye side effects after taking sildenafil called non-arteritic anterior ischemic optic neuropathy, also known as NAION. According to Brigham and Women’s Hospital, this causes the loss of blood flow to the optic nerve which then causes a sudden loss of vision. In this man’s case, he did not have NAION. However, it is unsure if it is the medication actually causing the condition or if people who take sildenafil are more likely to have other risk factors for the condition.



We Don’t Control the Weather…Microbes Do

Humans are continuing to alter the atmosphere by their activities and most human-induced methane comes from livestock and landfill.  But what people might not know is that micro-organisms have been doing this for billions of years.

Microbes are responsible for producing the methane. Microbes found in wetlands produce 160 million tons of methane a year and microbes that live in termites release 20 million tons.

Microbes also play a role in the amount of carbon absorbed and released from the atmosphere by the ocean, which is about 90 million tons a year. The combination of primary production and microbial decomposition on land leads to 120 billion tons of carbon taken in every year and 119 billion tons of carbon released.

Photo of climate change from Pixabay.

Dr. Reay claims, “The impact of these microbially-controlled cycles on future climate warming is potentially huge”. It is important to better understand these processes in order to take more carbon out of the atmosphere by using microbes in the sea as well as on land.

Picture of Cyanobacteria from Wikimedia Commons.

Bacteria can be used to catch methane that is released from landfill, Cyanobacteria could potentially provide us with hydrogen fuel, and plankton are continuing to become a feedstock for some biofuels. Either way, it is crucial to understand microbes in order to know whether they will help us to avoid climate change or will push us faster towards it.




Fecal microbiota transplants make cancer patients feel better within days

Studies show that autologous fecal microbiota transplantation (auto-FMT) restores a cancer patient’s healthy microbiome  after they receive intense antimicrobial therapy. Cancer patients go under allogeneic hematopoietic stem cell transplantation which requires intense antibiotics to make them feel more like themselves. FMT is a safe way of helping to replace beneficial bacteria that the patients may lose due to the antibiotics.

This image depicts autologous fecal microbiota transplants.

In order for allogeneic hematopoietic cell transplantation to take place, a donor, usually a sibling or parent, must give the recipient stem cells; this re-establishes bone marrow production of the blood cells and is what causes an immune function to cancer. This approach is favored because most patients have a donor in their family who is at least a 50% match. However, the process of reconstructing the immune system is slow because patients experience infections for a long time after the transplant takes place. To prevent bacterial infections in stem cell recipients, the antibiotics are necessary. These antibiotics, however, also break apart bacteria that is beneficial to the immune system and resistant to infection. This increases the risk of infectious diseases that can be life threatening.  

However, researchers from Memorial Sloan Kettering Cancer Center have now learned that auto-FMT can reverse the negative effects of antibiotic treatment. If what they conclude is validated, this may prove to be a simple way of quickly restoring a patient’s healthy microbiome following antimicrobial therapy.

The study done by the Memorial Sloan Kettering Cancer Center involved 25 cancer patients who provided their own stool sample. This sample was then frozen prior to the procedure. Weeks later, physicians confirmed that the transplanted cells were growing so the cancer patients were assessed to see the status of the beneficial bacteria. The first 25 patients who lacked beneficial bacteria were then used for the study. Each person was randomly assigned to a treatment group, which included 11 patients who received standard care and 14 who received auto-FMT. The researchers found that function was regained by the patients who received auto_FMT. These lucky patients recovered beneficial bacteria within days, restoring their immune and digestive functions. Those who did not receive auto-FMT had a delayed recovery of up to many weeks, leaving patients at risk of other infectious diseases.


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