BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: mouse

If You Give A Mouse…Sight!

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On April 23, 2023

In Student Post

In a recent study published in the Journal Of Experimental Medicine, researchers in China successfully used CRISPR Gene-Editing technology to restore sight to mice with retinitis pigmentosa.

That’s a lot of vocabulary all at once, so let’s establish some definitions first and foremost.  According to the National Eye Institute, retinitis pigmentosa is a “genetic disease that people [and animals] are born with…that [affects] the retina (the light-sensitive layer of tissue in the back of the eye)”. As for CRISPR Gene-Editing technology, YG Topics defines it as, “a unique technology that enables geneticists and medical researchers to edit parts of the genome by removing, adding or altering sections of the DNA sequence”.

Most inherent forms of blindness and loss-of-vision stem from genetic mutations, and thus retinitis pigmentosa is one of many forms of genetically caused blindness.  However, through CRISPR technology, the researchers in the study successfully edited the DNA of mice who had the mutation to eliminate retinitis pigmentosa and give them the ability to see.  The results of the study are very promising, as not only does retinitis pigmentosa affect mice, but human beings.  Thus, there is evidence that CRISPR could be used to cure blindness among everyday people.  Kai Yao, a professor from the Wuhan University of Science and Technology who contributed to the study said, “The ability to edit the genome of neural retinal cells, particularly unhealthy or dying photoreceptors, would provide much more convincing evidence for the potential applications of these genome-editing tools in treating diseases such as retinitis pigmentosa”.

In AP Biology, we discussed how DNA factors into the traits of a living being.  DNA is made up of 3 base codons that form up to 20 different amino acids.  These amino acids code for specific proteins.  Through a process of DNA transcription and translation, the DNA uses various forms of RNA to code for proteins, which help tell the cell what to do.  Thus, the way the cell acts is largely determined by its DNA.  Essentially, DNA codes certain traits through various amino acid sequences.  Mutations and alternations to amino acid sequences cause different traits, such as red hair, blue eyes, or blindness.

Thus, successfully altering the DNA of mice has huge implications for the human race.  CRISPR could potentially be used to edit the DNA of humans, and thus help limit and prevent certain genetic conditions.  Many diseases are based on genetic mutations, and if CRISPR Gene Editing technology is proven successful, we could potentially eliminate genetic diseases in a few decades.  While “much work still needs to be done to establish both the safety and efficacy” of CRISPR technology, some groundbreaking scientific treatments could be coming sooner than you think (Neuroscience News).

Мышь 2

A Baby Beetle’s Nursery is.. In a Dead Mouse?!

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On January 15, 2019

In Student Post

Two Parent Burying Beetles in a Dead Rodent! Gross!

Typically, death for animals is experienced at the end of one’s life, but this is reversed for a certain species of carrion beetle, Nicrophorus vespilloides or burying beetle, in which infant beetles are born and raised within dead mice carcasses. In this mice carcass, parent beetles frequently tend to the dead animal by soaking it with their own oral and anal secretions, providing the baby beetle with a much needed dark microbial film. This bacterial goo actually closely resembles the parent beetle’s gut microbiomes, allowing for the baby beetle to truly thrive as an offspring of this beetle.

But why give these baby beetles this goo within a dead carcass? What benefit would that ever give to an insect?

In every living thing, there is sphere of personal bacteria that provide much needed life benefits as well as qualities like your own stench. Plus, bacteria can even join together through various forms of cellular communication, making an almost impenetrable microfilm biome for bacteria to live in, as seen in plaque on human teeth. This same function is what helps support infant beetles with necessary nutrients and life benefits by keeping the cadaver fresh and capable of sustaining youngster life. Plus, it even causes dead bodies to smell actually not terrible, but instead more pleasant! Crazy! “What burying beetle parents can do with a small dead animal is remarkable,” says coauthor Shantanu Shukla of the Max Planck Institute for Chemical Ecology in Jena, Germany.  “It looks different. It smells different. It’s completely transformed by the beetles.”

If these insects aren’t exposed to these microbiomes as a child, there could be some serious detrimental effects. As shown by Shukla’s lab work, larvae grown in cadavers that were swept clean of biofilm by Shukla and her colleagues used their food less efficiently and gained less weight (“roughly third less weight per gram than those who had their parents goo”).

But, the parents are not the only ones who manipulate the carcass, which can be seen here. As parent beetles and tended to their goo in the body and guarding their children, the infant beetles also add their own secretions to the dead mouse and also eat away the bacteria as well as the entire mouse body. “What will remain is the tail of the mouse,” Shukla says, “and the skull and a few pieces of skin.”

Isn’t it simply crazy how much bacteria can contribute to the growth of a baby insect as well as its impact on even a dead animal? Comment below about what YOU think about this!

Loneliness Is Bad For The Brain

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On December 2, 2018

In Student Post

This new study from the Thomas Jefferson University in Philadelphia suggests that loneliness can have quite an impact on the brain. The study is based on the effects of social isolation on mice. The mice were raised together where they could play with each other and form social ties. Then they were separated from each other for months on end. The results were quite interesting.

File:Coronal section of a mouse brain stained with Hematoxylin & LFB.jpg

Cross Section of Mouse Brain

After about a month of isolation, the mice developed more “spines” on their dendrites. This is peculiar because this development would usually happen as a response to a positive stimulus. The researchers theorize that the brain is trying to save itself from the loneliness. But this effort is not long lived. After three months of isolation, the brain returns to baseline levels of neural activity. The brain also has reduced amounts of a protein called BDNF, responsible for neural growth. They also found increased amounts of the stress hormone cortisol. Lonely mice also had more broken DNA than their socialite counterparts.

Although it is not known how the results of this study can relate to the brains of humans it may shed some light into the lesser known effects of loneliness on the brain. It also brings into question the effect incarceration could have on a person long term and whether or not it could be more harmful than rehabilitating. What do you think about this study? What could the results of a similar test on humans yield?

CRISPR used to treat diabetes, kidney disease, muscular dystrophy

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On March 11, 2018

In Student Post

Scientists have now created a new method of using CRISPR genome editing, which would allow them to activate genetics without breaking the DNA. It could potentially be a major improvement in using gene editing techniques to treat human diseases. Currently, most of the CRISPR systems work by creating DSBs or Double strand Breaks in regions of the genome targeted for editing. Many scientists and researchers have opposed creating breaks in the DNA of living humans. So the Salk group tried their new method to treat diseases such as diabetes, kidney disease, and muscular dystrophy in the mouse models.

CRISPR has proved to be a powerful tool for gene therapy, but there are still many concerns regarding some mutations generated by the DSBs though the Salk group is able to get around that concern. Originally, Cas9 enzyme couples with guide RNA to create DSBs. But just recently, researchers have used a dead form of dcas9 to stop the cutting of DNA. DCas9 would couple with transcriptional activation domains, that turn on targeted genes. But it is still difficult to be used in clinical applications.

Salk group team combined dcas9 with bunch of activator switches to uncover a combination that would work even when the proteins are not fused with one another. These components all work together to influence endogenous genes. It would influence genetic activities without having to change the DNA sequence.

In order to prove the usefulness of this method, scientists used mouse models of acute kidney disease, type 1 diabetes, and a form of muscular dystrophy. They engineered their new CRISPR system to boost the expression of an endogenous gene that would reverse the symptoms of the disease. In all three cases, they reversed disease symptoms.

To understand more, click here.

 

Photo credit: Martyn Fletcher

 

#EpigeneticInheritance

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On March 8, 2015

In Student Post

Professor Marcus Pembrey of the University College of London transcribes the complexity of epigenetics into an understandable definition, simply put as “a change in our genetic activity without changing our genetic code.” The study of “epigenetic/transgenerational inheritance” has been a field of increasing popularity within the last decade, as studies and further research are beginning to show evidence of lifestyle stresses carrying over in the genome of each generation. Now, this is not to say that our grandparents way of living changed our DNA coding but rather potentially altered the way certain genetic information is or is not expressed.

 

To further explore the possibility of epigenetic inheritance, a laboratory in Boston conducted an experiment on three generations of mice.  A pregnant mouse was ill-fed in the late stages of pregnancy and as expected the offspring were born relatively small and later in life developed diabetes. However, the F2 generation experienced a high risk of acquiring diabetes, despite being well nourished. Another study on mice showed similar results; after a father was artificially taught to fear a particular smell, the offspring of that mouse also demonstrated a fear to the same smell.

 

Although the excitement over the groundbreaking research of epigenetics seems promising, researchers are still working to compile a stronger foundation of evidence to prove that this phenomena actually occurs in mammals. Professor Azim Surani of the University of Cambridge fully supports the idea of epigenetic inheritance in plants and worms, but has yet to commit to the same notion in mammals, as their biological processes differ greatly.

 

You Are What You Eat

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On December 11, 2014

In Student Post

Mouse

Whenever a person consumes healthier meals and therefore less calories, according to a new study on mice at the NYU Langone Medical Center, they could be lengthening their lives.

Using female mice, scientists fed one group of mice a diet of pellets containing a high amount of calories, while feeding another group of mice a diet of pellets containing 30% less calories. The hippocampus and the region surrounding it in the brains of the mice were then examined for expression of aging-genes throughout various stages of maturity. The results of the study, while not entirely applicable to humans, has shown that the mice that ate the lower calorie diets had less expression of aging genes and had less risk of chronic illnesses such as hypertension and stroke.

“The study does not mean calorie restriction is the ‘fountain of youth,’ but that it does add evidence for the role of diet in delaying the effects of aging and age-related disease.” Stated Stephen D. Ginsberg, a researcher involved with the study. The study examined more than 10,000 genes related to aging, which is a much larger amount than that previously studied by researchers. While the study was performed on mice, the results could be similar in humans, and the researched performed by Dr. Ginsberg and others should serve as a warning for our ever-indulgent world of fast food and high caloric intake.

Article:  http://www.sciencedaily.com/releases/2014/11/141117110650.htm

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