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G-force and C. elegans

Posted on Jun 14, 2019

c elegans
C. elegans

Could life have existed on other worlds in the distant past? Could that life have somehow managed to survive traveling through space on a meteorite or similar object? If so, could that life have colonized other planets, possibly even earth? This idea, that life could have traveled throughout the early solar system on interplanetary debris, is called ballistic panspermia.

The idea of ballistic panspermia can be traced back as far as the 18th century to the French diplomat and historian Benoît de Maillet. The idea gained more traction in 1984, when scientists found a Martian meteorite in Antarctica that appeared to contain what was thought to be fossilized nanobacteria. Most experts now believe that these structures are not strong evidence of extraterrestrial life, and likely either formed abiotically or were contaminated by contact with the Antarctic ice. However, this has not stopped scientists from testing hypotheses related to how life may be able to travel between planets.

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Gene Therapy and Usher Syndrome

Posted on Apr 18, 2019

adeno associate virus
Structure of an adeno-associated virus

It is almost like science fiction: the ability to manipulate the human genome to cure diseases by correcting genetic errors. Since the late twentieth century, scientists have been working towards making gene therapy a reality. Gene therapy offers a chance to treat genetic diseases at their source. It involves introducing therapeutic sections of DNA into a patient’s cells, with the aim of either having that DNA translate into proteins, interfere with faulty gene expression, or even correct genetic mutations.

Typical treatment involves encoding a functional, therapeutic gene as a polymer molecule that is packaged inside a “vector” to carry the polymer into the target cells. Most of the vectors chosen are viruses, since even harmless viruses are good at infecting cells. Some viruses are even able to have their genetic material copied into the host’s cell, which scientists can exploit as a method to deliver therapeutic DNA and integrate it into the patient’s genome. Since the treatment is focused on correcting individual genetic errors, research has been focused on diseases caused by single-gene defects, such as cystic fibrosis, hemophilia, muscular dystrophy, and sickle cell anemia.

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Testing Gene Drives in Mosquitos

Posted on Dec 19, 2018

mosquito

According to the World Health Organization (WHO), over half of the world’s population is at risk for malaria. In 2015 alone, the WHO recorded over 200 million cases of malaria worldwide and more than 400,000 deaths. Sub-Saharan Africa shoulders a large part of the burden of this disease. The main parasite responsible for transmitting malaria in Africa is the Anopheles gambiae mosquito. Scientists are looking into ways to curb the A. gambiae population as a means of preventing the spread of malaria.

One of the ways scientists are looking to control mosquito populations involves genetic engineering: gene drives. Gene drives result when researchers can modify a gene (e.g. using CRISPR/Cas-9) that also disrupts the normal processes of inheritance so that all offspring end up with the modified gene as well. This allows the gene drives to rapidly spread throughout a population. If, for example, the genetic modifications result in organisms that are sterile, a gene drive can rapidly crash or even exterminate a population. This could result in a local eradication of a disease-carrying parasite, such as A. gambiae.

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New Technique to Turn on Mouse Genes

Posted on Nov 5, 2018

CRISPR/Cas9

Over the last several years, the prospect of precision gene editing as a method of treating diseases has greatly increased. A major part of the increase in interest was the development of CRISPR/Cas9. CRISPR/Cas9 is a tool for modifying genes using technology borrowed from bacteria. This system uses a strand of RNA that is designed to only match up to a specific spot in the genome. This “guide” RNA leads the Cas9 enzyme to the target segment, where the enzyme cuts the DNA. Scientists can use the cell’s own repair mechanisms to add or delete pieces of genetic material at the location of the cut, allowing precise control of genetic mutation.

As this technology has developed, scientists have made different modifications to the tool. Many of these involve changing the Cas9 enzyme so that it attaches to a gene and activates it, instead of cutting it. Initially, these modifications created molecules too big to fit inside the viruses used to deliver them to their targets. However, earlier this year, Science News reported that researchers had developed a way to shrink the guide RNA by over 25%: from 20 units to 14-15 units. This new tool, which is known as CRISPRa, attaches to a gene and attracts proteins that turn the gene on. The researchers released a study last December detailing several experiments they performed on mice aimed at treating different genetic diseases.

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Fungi in Antarctica

Posted on Sep 27, 2018

Shackleton's hut

Shackleton’s hut

In the late nineteenth and early twentieth centuries, 17 expeditions were launched by 10 different countries to explore Antarctica. Ernest Shackleton and other adventurers traveled to the largely unexplored frozen continent to advance cartography, oceanography, and meteorology, as well as to seek the glory of being the first explorers to reach the south pole. In addition to the many scientific advances of these expeditions, they also left another legacy: wood buildings created for shelter, in an otherwise woodless environment. Now, a recent article in Scientific American talks about how scientists are finding fungi growing on these century-old wood structures.

Fungi have been crucial for the development of modern medicine. In addition to being the basis for penicillin, they are also critical for the immunosuppressant cyclosporine and the cholesterol drug lovastatin. With the ever-increasing threat of antibiotic-resistant pathogens, scientists are always on the lookout for new antimicrobial compounds.

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