BioQuakes

AP Biology class blog for discussing current research in Biology

Author: calalyst

Successful Progeria Treatment in Mice Also Bodes Well For Humans

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On March 12, 2019

In Student Post

A successful CRISPR-Cas9 treatment of Progeria in mice may be the beginning of anti-aging in humans.

When Juan Carlos Izpisua Belmonte set out to study “the molecular drivers of aging,” he could not have picked a more appropriate disorder than Progeria. Progeria is an accelerated aging disorder “caused by a mutation in the LMNA gene.” In both mice and humans, progeria induces many symptoms of aging, such as “DNA damage, cardiac dysfunction and dramatically shortened life span,” early in life. Molecularly, Progeria “shifts the production of lamin A,” a protein, ” to progerin,” a toxic form of lamin A that builds up with age.

 

 

In order to “to diminish the toxicity from the mutation of the LMNA gene that leads to accumulation of progerin inside the cell,” the Belmonte-led group used CRISPR-Cas9 to disrupt both lamin A and progerin. To do so, RNA first guides Cas9 to a spot on the DNA. Then, it makes a cut that “renders lamin A and progerin nonfunctional.”

As a result, the treated mice enjoyed a 25% longer life span and were stronger and more active. The successful treatment bodes well not only for mice, but for humans. In the future, “efforts will focus on making the therapy more effective” and compatible for humans.

 

 

Can Science Explain Love?

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On January 14, 2019

In Student Post

Sometimes it’s the greatest feeling in the world. Sometimes it hurts. Although we may never derive a fundamental recipe for it, much of love can be explained by chemistry and biology.

The brain (not the heart!) is responsible for romantic love, which, according to Dr. Helen Fisher at Rutgers University and Katherine Wu at Harvard University, can be broken down into three categories: lust, attraction, and attachment.

Credit: “Hearts” by eflon on Flickr.

Lust is our yearning for “sexual gratification.” This facet of love is grounded in our evolutionary, inherent need to reproduce. Lust is stimulated when the hypothalamus releases “sex hormones (testosterone and estrogen) from the testes and ovaries.”

Whereas lust concerns merely “sexual gratification,” another aspect of love, attraction, encompasses a variety of emotions with regard to a specific person. Attraction leads to the release of the chemicals dopamine and norepinephrine. As anyone whose ever been attracted knows, these chemicals make us “giddy, energetic, and euphoric.” Attraction also stimulates the brain’s reward center, which fires “like crazy when people are shown a photo of someone they are intensely attracted to.” Another hormone, serotonin, is found in low levels in both people with obsessive-compulsive disorder and people those who are experiencing attraction. As a result, scientists have theorized that attraction, and the ensuing low level of serotonin, is responsible for the obsessive infatuation so common in love.

The third aspect of love, attachment, is responsible for intimacy, is a key factor in long-term relationships, and is, of course, mediated by hormones.  The two hormones responsible for attachment, oxytocin and vasopressin, “are found in large quantities during sex, breastfeeding and childbirth,” all activities that are “precursors to bonding.” From this, it is easier to understand the concept of three different aspects of love: the “love” parents feel towards their children is merely the attachment aspect of it, but neither the lust nor the attraction aspect.

Although science can give us a biological basis for it, love, and all of its intricacies, can never be fully explained.

Microbiome Genes have Macro-significance

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On November 8, 2018

In Student Post

Ever been told that the little things matter in life? This same proclamation that you’ve been told by your elders rings true in your gut: one small modification to your human gut microbiome (a batch of bacteria that call your digestive tract home) can have drastic effects on your metabolism.

A. Sloan Devlin, assistant professor at Harvard medical school, carried out a study that proved the importance of the gut microbiome. She first located the gene in “an abundant gut bacterium” for an enzyme that processes bile acids. She then removed that gene from the bacterium. Next, she “colonized” “germ-free” mice with one of two types of the gut bacterium: either with the bile-processing enzyme or without the bile-processing enzyme. The results were surprising.

Credit: mcmurryjulie on pixabay

After both mice were fed the same high-fat, high-sugar diet, the mice without the bile-processing enzyme “had more fat in the liver and gained weight much more slowly than the other group. They also used proportionately less fat and more carbohydrate for energy.” Changing one single enzyme in a gut bacterium appears to change “whether the host is using [primarily] fats versus carbohydrates” for energy.

Even more staggering was the “correlation of lean body mass to energy expenditure.” Typically, in humans and mice, the more lean body mass an organism has, the more energy it expends. However, for the mice without the bile-processing enzyme, this relationship “broke down.” Devlin hypothesizes that this change could be due to a “signaling,” a process in which “physical states in the body trigger a cascade of genes to switch on or off.” Researchers can use this knowledge to treat diseases: figure out which microbiome bacteria activate which genetic switches, and better treatment for genetic problems such as, acid imbalances, metabolic disorders and obesity, may become a reality.

Devlin is sure to stress that this groundbreaking microbiome research is just her “first step.” Although this study was carried out on “germ-free” mice, Devlin dreams that one day she may use her research to improve the health of her own species: as Devlin states, her research brings her “one step closer to humans.”

 

Malevolent Personality Traits Come in a Package

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On October 10, 2018

In Student Post

Credit: emeraldschell from Flickr

Nearly a century ago, Charles Spearman found that “people who score highly in one type of intelligence test typically also score highly in other types of intelligence tests.” As a result, he concluded that there is a “general factor of intelligence.” Based on new research from “Ingo Zettler, Professor of Psychology at the University of Copenhagen, and two German colleagues, Morten Moshagen from Ulm University and Benjamin E. Hilbig from the University of Koblenz-Landau,” a similar “general factor” can be used when measuring a person’s “dark core of personality.”

The “dark personality” traits that the researches studied are egoism, machiavellianism, moral disengagement, narcissism, psychological entitlement, psychopathy, sadism, self-interest, spitefulness. To carry out their study, the researches asked more than 2,500 people to what extent they disagreed or agreed with statements such as ‘It is hard to get ahead without cutting corners here and there.,’ or ‘It is sometimes worth a little suffering on my part to see others receive the punishment they deserve.’ The study’s results painted a clear picture.

The research showed that the aforementioned “dark personality” traits are all based upon the same tendency. Therefore, a person with one “dark personality” trait will be more likely to also possesses many others. This “common denominator of all dark traits” is dubbed the “D-factor.” More specifically, the “D-factor” is “the general tendency to maximize one’s individual utility — disregarding, accepting, or malevolently provoking disutility for others — , accompanied by beliefs that serve as justifications.”

In the future, an assessment one’s “D-factor” may come in handy for everyone from therapists treating patients, to school teachers handling young children, to employers hiring for jobs.

Credit : affen ajlfe from Flickr

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