BioQuakes

AP Biology class blog for discussing current research in Biology

Author: jdna

More CRISPR Improvements

Crispr-Cas9 is a genome editing tool that is creating a whole lot of buzz in the science world. It is the newest faster, cheaper and more accurate way of editing DNA.  Crispr- Cas9 also has a wide range of potential applications. It is a unique technology that enables geneticists and medical researchers to edit parts of the genome by cutting out, replacing or adding parts to the DNA sequence.  The CRISPR-Cas9 system consists of two key molecules that introduce a mutation into the DNA. The first Molecule is an enzyme called Cas9. Cas9 acts as a pair of scissors that can cut the two strands of DNA at a specific location in the genome so that bits of DNA can be added or removed.  The second is a piece of RNA called guide RNA or gRNA. This consists of a small piece of pre-designed RNA sequence located within a longer RNA scaffold. The scaffold part binds to DNA and the pre-designed sequence guides Cas9 to the right part of the genome. This makes sure that the Cas9 enzyme cuts at the right point in the genome.Screen Shot 2016-04-10 at 4.50.55 PM

CRISPR-Cas9 is efficient compared to previous gene-editing techniques, but there’s still plenty of room for improvement. CRISPR is less efficient when employing the cellular process of homology-directed DNA repair, or HDR, as opposed to nonhomologous end joining.  Jacob Corn, the scientific director of the Innovative Genomics Initiative at the University of California, Berkeley, and his colleagues have come up with a way to improve the success rate of homology-directed repair following CRISPR-Cas9. “We have found that Cas9-mediated HDR frequencies can be increased by rationally designing the orientation, polarity and length of the donor ssDNA to match the properties of the Cas9-DNA complex,” the researchers wrote in their paper, “We also found that these donor designs, when paired with tiled catalytically inactive dCas9 molecules, can stimulate HDR to approximately 1%, almost 50-fold greater than donor alone.”

“Our data indicate that Cas9 breaks could be different at a molecular level from breaks generated by other targeted nucleases, such as TALENS and zinc-finger nucleases, which suggests that strategies like the ones we are using can give you more efficient repair of Cas9 breaks,” coauthor Christopher Richardson, a postdoc in Corn’s lab, said in a statement.

Original Article:

http://www.the-scientist.com/?articles.view/articleNo/45159/title/More-CRISPR-Improvements/

Other Addtional Helpful Links:

http://www.yourgenome.org/facts/what-is-crispr-cas9

 

Joint Pain? Blame it on the Gut.

That sharp pain we feel in our knees after jumping rope, the pains we feel in our elbows after shooting all of those foul shots, even the pain we feel in our fingers while typing AP Bio Blog Posts.  You all know this feeling of joint pain I’m talking about, and if you don’t right now, you will in 15-20 years… trust me.  Professionals aren’t entirely sure of the real causes regarding joint pain leading to rheumatoid arthritis, but an emerging body of research is focusing on a potential culprit: the bacteria that live in our gut.

Screen Shot 2016-01-13 at 11.17.25 PMScreen Shot 2016-01-13 at 11.22.40 PM

 

Many recent studies have found intriguing links between our gut microbes, rheumatoid arthritis, and other diseases in which the body’s immune system goes wrong and attacks its own tissue. Microbes are especially influential in the gut and as the pathway for digestion, the gastrointestinal tract must deal with a constant stream of food-related foreign microbes, which must be monitored and, if they are harmful, destroyed. To do this, our intestines have developed an extensive immune system, whose effects reach far beyond the gut. Immune cells in the gut seem to be able to activate inflammatory cells throughout the body, including in joints.  A study published in 2013 by Jose Scher, a rheumatologist at New York University, found that people with rheumatoid arthritis were much more likely to have a bug called Prevotella copri in their intestines than people that did not have the disease. In another study published in October, Scher found that patients with psoriatic arthritis, another kind of autoimmune joint disease, had significantly lower levels of other types of intestinal bacteria.

Over the past several years, scientists have collected a growing collection of evidence stating that many of these bugs may have a major effect on our well-being. Some trigger chronic, non-infectious ailments such as rheumatoid arthritis while others actually prevent against such diseases. But while many scientists are confident of the link between the microbiome and arthritis, they haven’t pinned down what particular role bacteria play in triggering the disease. Scher says Prevotella copri may stimulate an immune reaction that then targets joint tissue. Or it may crowd out beneficial microbes that keep immune-system attack cells being too aggressive.

Venna Taneja, an immunologist at the Mayo Clinic in Rochester, Minnesota, who has found clear differences in the bacterial populations of mice bred to be genetically prone to rheumatoid arthritis stats “It’s become more and more clear that these microbes can affect the immune system, even in diseases that are not in the gut.”  She has found clear differences in the bacterial populations of mice bred to be genetically prone to rheumatoid arthritis. In those more susceptible to the disease, a species of bacteria from the Clostridium family dominates. In mice without arthritis, other strains flourish, and the Clostridium strains are scarce.

As the years ago on, the study of joint pain and arthritis in correlation with the Gut Microbes will grow and one day these many scientists will figure out a way to work out the negatives of this bacteria and use it solely to a person’s benefit.

Original Article

Additional Sources and Reading:

http://www.mindbodygreen.com/0-17066/could-your-gut-be-the-cause-of-your-joint-pain.html

Global Warming can alter the shape of the planet

Climate change is an element in our world which has been around for many years. It has been believed to cause warmer oceans and erratic weather, but a new study, according to scientists, declares it also has the potential to alter the shape of the planet we live in. Global Warming is a gradual increase in the overall temperature of the earth’s atmosphere generally attributed to the greenhouse effect caused by increased levels of carbon dioxide, chlorofluorocarbons, and other pollutants. (read more about Global Warming) Michele Koppes,  assistant professor in the Department of Geography at the University of British Columbia, conducted a five year study in which she compared glaciers in Patagonia and in the Antarctic Peninsula. Koppes and her team discovered that glaciers in warmer Patagonia moved faster and caused more erosion than those in Antarctica, as warmer temperatures and melting ice helped lubricate the bed of the glaciers.

global warming

 Glaciers erode 100 to 1,000 times faster in Patagonia than they do in Antarctica.   “Antarctica is warming up, and as it moves to temperatures above 0 degrees Celsius, the glaciers are all going to start moving faster,” states Koppes. These ice sheets are apparently beginning  to move faster and should become more erosive. As a result, this will dig deeper valleys and shed more sediment into the oceans. The outcomes of this erosion add to the already complex effects of climate change in the polar regions.  “The polar continental margins in particular are hotspots of biodiversity, If you’re pumping out that much more sediment into the water, you’re changing the aquatic habitat,” Koppes states.  The Canadian Arctic, one of the most rapidly warming regions of the world, will most definitely feel these effects. These glaciers are on the verge of a major shift. The Canadian Arctic is becoming warmer in temperature more than four degrees Celsius spanning over the last 50 years. These glaciers will be flowing up to 100 times faster if the climate continues to shift and shifts above zero degrees Celsius. The findings by Koppes settle a scientific debate about when glaciers have the greatest impact on shaping landscapes and creating relief, suggesting that they do the most erosive work near the end of each cycle of glaciation, rather than at the peak of ice cover. If global warming continues to occur, change in formation of landscape due to higher water levels from melting glaciers is a strong possibility and may already be taking place. This will significantly affect all forms of life on earth.

 

Original Article:  http://www.sciencedaily.com/releases/2015/10/151001142222.htm

Citations:

http://www.whoi.edu/main/topic/global-warming

http://www.sciencedaily.com/releases/2015/10/151001142222.htm

 

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