BioQuakes

AP Biology class blog for discussing current research in Biology

Author: dnaitza

Anti-CRISPR Proteins: What are they and can they be beneficial?

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On April 5, 2017

In Student Post

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Understanding CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)

For many bacteria, one line of defense against viral infection is the RNA guided “immune system” known as CRISPR-Cas. This particular complex is unique because of its ability to recognize viral DNA and trigger its destruction. Scientists have used CRISPR to degrade sections of viral RNA and use the CRISPR systems to remove unwanted genes from an organism. CRISPR proteins have also been studied with the hope of eliminating serious disease and illnesses. However, this CRISPR system does not always work do to anti-CRSPR proteins that inhibit the complex from working properly.

Research 

According to an article on ScienceDaily, researchers have finally discovered how these anti-CRISPR proteins work! Research done by biologist Gabriel C. Lander from the Scripps Research Institute, discovered that anti-CRISPR proteins work by inhibiting CRISPR’s ability to identify and attack viral genomes. Just like there are different CRISPR systems, there are multiple anti-CRISPR proteins as well. One in particular mimics DNA to throw the CRISPR-guided detection machine off its course. Scientists have been able to further discover certain aspects of CRISPR and anti-CRISPR systems by using a high-resolution imaging technique called cryo-electron microscopy. They have discovered that the CRISPR surveillance complex analyzes a virus’s genetic material to see where it should attack by having proteins within the complex wrap around the CRISPR RNA, exposing specific sections of bacterial RNA. These sections of RNA then scan viral DNA, looking for genetic sequences they recognize. Lander describes these proteins as being very clever because they “have evolved to target a crucial piece of the CRISPR machinery. If bacteria were to mutate this machinery to avoid viral attacks, the CRISPR system would cease to function.” Therefore, CRISPR systems cannot avoid anti-CRISPR proteins without completely chancing the mechanism used to recognize DNA. Another type anti-CRISPR protein works a bit differently. Based on its location and negative charge, this anti-CRISPR protein acts as a DNA mimic, fooling CRISPR into binding this immobilizing protein, rather than an invading viral DNA.

Can Anti-CRISPR Proteins be beneficial?

Researchers are saying that the understanding of how these anti-CRISPR proteins work are extremely important! According to an article on GEN, the discovery and understanding of anti-CRISPR proteins actually allows researchers to have greater control over gene-edits. In this article, Dr. Sontheimer, a professor in the RNA The RNA Therapeutics Institute at UMass Medical School, expressed how “CRISPR/Cas 9 is a good thing because it introduces specific chromosome breaks that can be exploited to create genome edits, but because chromosome breakage can be hazardous, it is possible to have too much of a good thing, or to have it go on for too long.” Anti-CRISPR proteins can be beneficial and work as an off switch for CRISPR, therefore advancing gene editing!

 

 

 

MRIs Catch Autism Prior to Symptoms

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On March 1, 2017

In Student Post

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Research

By using magnetic resonance imaging (MRI), researchers are now able to accurately study and predict which infants, among those with older autistic siblings, will be diagnosed by the age of 2. According to an article on Science daily, in the past couple of years, researchers have correctly predicted 80 percent of these infants who would later meet criteria for autism at 24 months of age.

A study published in Nature, shows how early brain biomarkers can be very beneficial in identifying infants at the highest risk for autism prior to any symptoms. Joseph Piven, professor of Psychiatry at the University of North Carolina-Chapel Hill, explains how typically autism cannot be detected in infants until they ages 2-4, but for infants with autistic siblings, it can be determined at an earlier age.

People diagnosed with Autism Spectrum Disorder (ASD), experience social deficits and  demonstrate very specific stereotypical behaviors. According to this study, it is estimated that one out of 68 children develop autism in the United States and that  for infants with older siblings with autism, the risk may be as high as 20 out of every 100 births. Despite these high numbers, it remains a difficult task to detect behavioral symptoms prior to 24 months of age.

Piven, along with a couple of other researchers, conducted MRI scans of infants at six, 12, and 24 months of age. They discovered that increased growth rate of surface area in the first year of life was linked to increased growth rate of overall brain volume in the second year of life. This meant that brain overgrowth was tied to the emergence of autistic social deficits in the second year. The researchers then took the information they had and used a computer program that classified babies most likely to meet criteria for autism at 24 months of age, and developed an algorithm that they applied to a separate set of study participants.

The researchers found that there were brain differences at 6 and 12 months of age in infants with older siblings with autism and infants with older ASD siblings who did not meet criteria for autism at 24 months.

Plans for the Future

This research and test would be very beneficial to a family who already has a child with autism and has a second child who may or may not be affected. The ideal goal would be to intervene and provide as much assistance to the infant and family prior to the emergence of symptoms. By intervening at early stages and when the brain is most susceptible, researchers hope to improve the outcomes of treatment.

In the nature study, Piven describes how Parkinson’s and Autism are similar in that when the person is diagnosed, they’ve already lost a substantial portion of the dopamine receptors in their brain, making treatment less effective.

One mother who has benefitted from this discovery and is extremely grateful is Rachel O’Connor. When interviewed by News12, she shared how early intervention “has brought out some language in [her] daughter,” and how her daughter “can now say what she wants and she desires. She makes better eye contact.”

 

Evolution of the Human Gut Microbiome

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On January 11, 2017

In Student Post

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According to an article on Science Daily, Westerners have a very different human gut than hunter-gatherers. Research suggests that Westerners tend to have a less diverse human gut. However, the reason for why is still unclear. Researches from this study have observed two particular groups of people. The hunter-gatherers, known as BaAka pygmies, relied on foods such as fish, fruits, and vegetables. Whereas the group of Westernizers, the Bantu, relied on a market economy. The Bantu grew fruits, other plants and raised goats. They also used antibiotics and therapeutic drugs available.

The results of the study revealed that while the  BaAka and Bantu gut microbes were from similar bacterial species, the abundance of traditional bacterial groups was decreased in the Bantu. When researchers delved into what could have caused the difference between the two groups, they found that diets are the most important driver of microbiome composition in humans.

Another study done by evolutionary biologist, Andrew Moelle, suggests that humans and animals have inherited some bacteria from their ancestors. Moelle studied three types of bacteria living in the feces of wild chimps, bonobos, gorilla and a group of people from Connecticut. He concluded that 2 of the three bacterial trees matched primate relationships. Moelle also expressed how these relationships are getting harder to study due to the effect that industrialization and antibiotics have. They have reduced the diversity of bacteria living in and on humans.  Microbial geneticist, Julia Segre, expressed that humans have been exposed to antibiotics and modern life and as a result, Wild African apes might “still have their ancient gut flora, but the people in Connecticut might not.

A study done by Howard Ochman found that human guts most closely resemble the gut of a gorilla. Like the other researchers, Ochman acknowledges that as a result of modern humans there is a loss of microbial diversity. He also explains how this can be a problem because humans have lost a number of bugs that help digest plant matter. However, humans have gained others that help digest meat.

 

Number of strokes increased in children!

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On November 28, 2016

In Student Post

Sean Maloney stroke brainscan

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Statistics 

According to new studies, strokes have been affecting younger generations more than ever. The average age for people having a first stroke has dropped from  71.1 in 2000 to 69.3 in 2012.What’s interesting is that in general, the number of strokes in the U.S. has actually gone down over the last few decades, according to Chengwei Li, an epidemiologist at the University of Michigan School of Public Health. However, Li’s study, shows that the rate of strokes in people under the age of 65 have not gone down, and that the rate of strokes in people under the age of 55 has actually increased.

Treatment

According to a study on WebMD, it is in some ways easier to treat the younger patients affected. People who get to the hospital within 4 and a half hours of their episode, or attack, can receive a drug that breaks up the clot in the brain and restores the blood flow. However, studies have shown that this treatment is more likely to benefit younger patients opposed to elder patients. Although this may be the case, young adults and females in particular, are often not eligible for the treatment because they ignore early symptoms or wait until the symptoms get severe, before they seek help.

As stated in an article from Live Science  and a journal from NCBI, the increase in stroke incidents at younger ages has great significance because strokes in younger patients carry out for a greater lifetime burden of disability.

While the total number of strokes in the U.S. has decreased, the number and severity of strokes in younger generations has increased. As a result, researchers, doctors, and medical staff continue to work together in order to seek ways to treat the newer generation of stroke patients.

Transgender- Science Behind Sexual Identity

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On October 13, 2016

In Student Post

Stop Homophobia - NUS Sports Gay Protests, London

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Transgender concepts have been a prevalent issue. It has been seen on a celebrity level with Caitlyn Jenner but on smaller levels as well. Schools are struggling to make decisions of whether to make bathrooms same-sex or unisex. While administrative figures are struggling to make accommodations for the increasing number and popularity of LBGT rights, society is also struggling to determine whether trans-gender identity is a social or biological doing.

One recent finding has shown that anatomical sex- gender identity and orientation- is determined in the womb. However, once the anatomy is settled, there is about a six month lag before the brain masculinizes or feminizes. Research has concluded that through some combination of genetics, hormones and the uterine environment, sometime between six months and delivery the sexual orientation is set in the brain. The only question that rises is what happens when the brain does not match the genitals.

Genetics has been proved to play a role in transgender identity. Researches studied a group of twins where either one or both were transgender.  In identical twins, 39% were both transgender. Of the fraternal twins, there were zero pairs where both were transgender. In fact a study in the Journal Biological Psychiatry, researchers found a gene variant that was associated with being a trans woman.

For the 61% of identical twins where only one is transgender, the prenatal environment, or womb, had a key role. While identical twins share genetic codes, the genes that get expressed or remain unexpressed differ. Identical twins have separate umbilical cords , separate amniotic sacs, and develop in separate locations of the womb. All these things can have an affect in the mixing of chemicals and the sexual identity process.

Lastly, the structure of the brain also plays a role. A 2014 study from the Journal of Neuroscience found that “differences in the brain’s white matter tracts [fall] along a perfect spectrum of gender identity with cisgender men and women at the ends and trans men and women in the middle.”

 

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