BioQuakes

AP Biology class blog for discussing current research in Biology

Author: izerstellar

Forget DNA, Let’s Talk RNA!

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On April 13, 2016

In Student Post

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Photo of RNA (licensing information here)

The genetic code within DNA is responsible for determining who we are and what we are capable of. Because of this, scientists have been interested in cracking the genetic code and finding ways to alter it. There are many diseases linked to DNA, as well as RNA. However, scientists have not been as successful in targeting RNA in living cells as they have been in targeting DNA. Recently, using CRISPR-Cas9, researchers at University of California, San Diego School of Medicine have figured out how to do what has been troubling scientists.

Senior author Dr. Gene Yeo described how the researchers at UCSD have been tracking the movement of RNA throughout cells and plan to measure other RNA features and help to correct disease-causing RNA behaviors using CRISPR-Cas9. The location of RNA in a cell determines whether proteins are produced at the right time and in the right place. When defective RNA transport occurs, diseases ranging from autism to cancer can occur. In order to successfully treat these conditions, researchers must find a way to track and measure the movement of RNA. This process was first seen with DNA: scientists found they could use CRISPR-Cas9 to track and edit genes in mammalian systems. Now, however, Yeo and his colleagues at UC Berkeley have started to target RNA in live cells (RNA-targeted Cas9 or RCas9), as well as DNA in live cells.

When CRISPR-Cas9 is used for normal DNA-involved purposes, researchers design “guide” RNA to match the DNA sequence of the gene Cas9 is targeting. The “guide” RNA then directs the Cas9 enzyme to the target spot in the genome. The Cas9 enzyme then cuts the DNA, which causes the DNA to break in a manner that inactivates the gene. Researchers can also replace the section of the genome next to the cut DNA with a corrected version of the gene. In order to allow Cas9 to work for RNA as well as DNA, work originated by co-author Dr. Jennifer Doudna at UC Berkeley laid a base foundation for researchers to design the PAMmer: a short nucleic acid. The PAMmer works with the “guide” RNA to direct Cas9 to an RNA molecule, instead of DNA.

All in all, CRISPR-Cas9 is responsible for a revolution in genomics with it’s ability to target and modify human DNA. Although this breakthrough is crucial, scientists are now trying to use their lead to target and modify RNA. With an extension on already existing research, there is no doubt that scientists will soon be able to do more than just track RNA. So, let’s forget about DNA and shine a light on RNA for a little while!

Source

Is it Really Your Choice to Make Better Choices?

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On February 29, 2016

In Student Post

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Obesity has become an increasingly prevalent epidemic around the globe and especially in the United States. Obesity has numerous roots. Recently, researchers from the McGill Centre for the Convergence of Health and Economics found that in some circumstances, it is possible to blame obesity not solely on genetic make-up, but rather on genetic make-up and socio-economic background combined. The McGill researchers discovered that the fat intake of a female who is a carrier of DRD4 VNTR with 7 repeats, a specific gene variant, is determined by the interaction of the female’s socio-economic environment with the gene. This gene variant affects about 20% of the population and is commonly related to obesity, especially in females. Males are typically not as affected by the gene because when comparing males and females at the same age, males do not typically show the same pattern of food preferences.

In order to research this topic, McGill researchers randomly selected about 200 Canadian children with an average age of 4 from the MAVAN birth cohort in Montreal, Quebec and Hamilton, Ontario to take place in the experiment. The McGill researchers used food diaries kept by the parents of every child in order to determine what was being eaten and how often the child was fed. The researchers were able to calculate the percentages of fat, protein, and carbohydrates the children were consuming, as well as the BMI of every child. Since the children were selected at random, the researchers tested every child for the gene variant using a saliva test. The researchers also analyzed the socio-economic background of every child and availability of particular foods based off of the family’s income.

Laurette Dubé, Scientific Director at this particular Centre at McGill and lead researcher on the study, analyzed the results. Dubé found that when comparing two females from the same socio-economic background, one with the gene variant and one without, the female with the gene variant had a higher fat intake, even though the two females came from the same socio-economic background. She also discovered that when comparing two females with the gene variant, one coming from a wealthy family and one coming from a poor family, the female coming from the poorer family had a higher fat intake, despite the fact the two females were both carriers of the gene variant. This newly found research led the McGill research team to believe that the gene alone does not determine an individual’s fat intake, but instead the gene causes an individual to be more sensitive to his or typically her environmental conditions that determine what are “good” eating patterns and what are “bad” eating patterns. Dr. Robert Levitan, co-invesitgator on the project, leader of the childhood obesity program of the MAVAN cohort, and Senior Scientist at the Centre for Addiction and Mental Health (CAMH), is an expert on the DRD4 gene in adult female “overeaters”. Levitan said, “We previously assumed that the 7-repeat variant caused weight gain in these patients by increasing the rewarding aspects of certain foods. These new results suggest a different way that the gene might affect food choices” (Biology News).

In certain cases, obesity isn’t all about genetic make-up, but the likeliness of obesity is determined by the socio-economic background of an individual as well! So, if you are a carrier of the DRD4 VNTR with 7 repeats gene variant, which, because of your environment, impacts your decisions, is it really your choice to make better choices?

Source: Biology News 

 

It’s Time to Re-program the Human Gut

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On January 9, 2016

In Student Post

(Photo of the human gut (licensing information here)

“What kind of water would you like? Tap or bottled?” “Bottled, please.”

It is known that when traveling internationally, it is typically unsafe to drink tap water. This is due to the lack of familiarity with the filtering systems used by other countries. This caution extends to certain foods as well. However, Dr. Pamela Silver, Dr. Jeffrey Way, and Dr. Donald Ingber, investigators at Harvard’s Wyss Institute for Biologically Inspired Engineering, may have found a solution to many acute gastrointestinal illnesses, such as this one, that affect the human gut microbiome.

Their goal is to create a bacteria that can detect and fight microbial invaders. This genetically engineered bacteria will specialize in detecting the chemicals given off by gastrointestinal inflammation. After the bacteria makes the detection, it will begin to attack all microbial invaders and restore normality within the gastrointestinal tract. The bacteria will be created in a probiotic pill form. In order to make sure that this probiotic pill does not have a negative impact on the environment after it exits the gastrointestinal tract, Silver and Way will ensure that it will not work unless it is in a specific environment and is triggered by specific chemical signals, both specific to the environment and signals found in the gastrointestinal tract.

Silver, Way, and Ingber will use the gut-on-a-chip technology to test this probiotic pill. The gut-on-a-chip technology will allow them to mimic gastrointestinal inflammation with living human cells. The team plans to study the response of invaders and pathogens, that are causing the inflammation, to the genetically engineered bacteria.

This research will allow for the treatment of a multitude of gastrointestinal illnesses, as well as the introduction to treating other diseases that negatively impact the human gut microbiome. I would love not having to worry about what I drink or eat on vacation! I am excited to see where this newly found research takes the discussion and the treatment of illnesses related to the human gut micobiome.

Source: Biology News

Attention all penicillin-allergy victims, you might not actually be penicillin-allergic!

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On November 9, 2015

In Student Post

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Photo of antibiotics (licensing information here)

I am someone who is allergic to penicillin, amoxicillin, and a bunch of other “cillins”. So, when being prescribed with antibiotics, penicillin is always ruled out as an option for treatment. However, new findings at the American College of Allergy, Asthma, and Immunology (ACAAI) show that people, like me, who were told after a single allergic reaction to penicillin that they were penicillin-allergic, may not be penicillin-allergic after all!

At the Annual Scientific Meeting at the ACAAI, a study was presented where 15 students who were supposedly penicillin-allergic tested negative for a penicillin allergy and were in fact treated with intravenous penicillin medication multiple times. Dr. David Khan and Dr. Roland Solensky, both allergists, are both majorly involved in this research. They each stated that people who are found allergic to a medication such as penicillin are then prescribed with more expensive and dangerous medications to take the place of the medication they are allergic to. In fact, almost 10% of Americans are labeled penicillin-allergic and have no choice but to use more complex medications, when they might not even be allergic to a simpler medication, such as penicillin, in the first place!

To attempt to resolve this problem, Dr. Solensky is going to present “Drug allergy: options beyond avoidance” at the next Annual Meeting at the ACAAI. This presentation is designed to discuss different treatment options for patients suffering from allergies to certain medications, as well as patients who were told they are allergic to medications that they are in fact not allergic to. Dr. Khan encourages everyone who is penicillin-allergic to get tested and see if penicillin is a medication they should actually avoid or if the allergic reaction they once had to penicillin was a fluke. This study can help people avoid medications that are overly expensive or that can be dangerous, and just in general help people find more appropriate medications. I sure know that I’m interested to see if I’m actually penicillin-allergic, or if that allergic reaction I had in second grade was a one time thing!

Main article:

http://www.biologynews.net/archives/2015/11/05/consider_penicillin_even_if_you_have_had_a_prior_reaction.html

Is Mars more like Earth than we think?

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On October 12, 2015

In Student Post

Photo of Mars (licensing information here)

For a long time, Mars was thought to be inhabitable.  However, there were always “what ifs” and hopes that one day Mars would be identified as a place where humans could survive and live comfortably.  Recently, researchers found recurring slope lineae (RSL) on the Martian slopes of Mars to be caused by a salty liquid.  We all know the most important aspect of life is water, something no one can live without and life on Earth cannot go on without.  So, if water is crucial to life on Earth, wouldn’t that mean that finding water on Mars points towards the potential for life there as well?

Researchers used the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard the Mars Reconnaissance Orbiter (MRO) in four different locations on Mars where RSL were present.  There were signs of hydrated salts in all four locations during the seasons when RSL are largest and most prominent.  RSL range from .5 to 5 meters wide, but have no limit to how expansive they are downslope.  CRISM analyzes Mars at 3:00 p.m., which in Martian time is the hottest time of the day.  This means that any liquid on the surface of Mars would have evaporated during this time, making it virtually impossible for the CRISM to identify water in its liquid form.  However, hydrated salts precipitate from liquid water, meaning that even if there was no water found there at the time the CRISM analyzed that location, there was water there at one point in time.  The salts associated with RSL are perchlorates, which lower the freezing point of water from 0° C (32° F) to -70° C (-94° F)! Researchers believe this points to a larger possibility for the stability of salt water on Mars.

However, even with all this excitement, researchers are still hesitant to make the claim that there are extremely high odds for the ability of life on Mars.  Due to the low water activity of perchlorates, researchers believe it would be hard for any living organism to survive with this as their only water supply.  Head researcher Lujendra Ojha cautions people who are tempted to jump to the conclusion Mars is now considered habitable for humans.  However, people can still hope that one day Mars may offer a second home to human beings, especially with this new exiting find!

 

Main articles:

http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2546.html

http://www.livescience.com/52322-water-flows-on-mars-discovery.html

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