Class blog for sharing and commenting on current events in biology.

Thursday, October 31, 2013

Faulty Stem Cell Regulation May Contribute to Cognitive Deficits Associated with Down Syndrome


Brennan O'Toole
Core Biology H/D Even
Ms. Davies

Conger, Krista. "Faulty Stem Cell Regulation May Contribute to Cognitive Deficits Associated with Down Syndrome, Study Suggests." Stanford Medicine. N.p.,11 Sept. 2013. Web. 27 Oct. 2013.

"Faulty Stem Cell Regulation May Contribute to Cognitive Deficits Associated with Down Syndrome, Study Suggests"
           
Recently, researchers at the Stanford University School of Medicine have discovered that the overexpression of a specific gene, known as Usp16, on chromosome 21 may be responsible for the cognitive issues exhibited by people with Down syndrome. The researchers, namely Michael Clarke, discovered this when they noticed defects in the stem cells of both the mice and human tissues they tested. Humans with Down syndrome usually have three copies of chromosome 21 and therefore multiple copies of the Usp16 gene that accelerate the uses of stem cells in early development. Therefore, by the time people with Down syndrome reach adult hood, they have overused their stem cell pools and tissue regeneration, making them vulnerable to early onset neurodegenerative diseases. This gene also makes it harder for the skin and neural progenitor cells in humans, which are the “self-renewing cellular factories responsible for the development and maintenance of many of the cell types in the brain,” to form neurospheres more slowly; this is compared to the study of Down syndrome cases whose Usp16 expression was lessened with drugs which in turn allowed for the skin and neural progenitor cells to develop at a normal rate. And so, the researchers in this study highlighted the fact that by reducing the expression of the Usp16 gene on chromosome 21, the cognitive function in humans with Down syndrome will be significantly improved, as it will balance their stem cell levels. They proved this through the results they obtained from two mice chains: Ts65Dn, who has three copies of Usp16, and Ts1Cje, who only has two copies of the gene; Ts65Dn is more closely related to the human symptoms of Down syndrome than Ts1Cje. The study found that the cells of Ts65Dn were less able to renew themselves through cell division than Ts1Cje, proving that subjects with less copies of the Usp16 gene were to able function more normally. The researchers used this information to suggest that by blocking the expression of one copy of the gene in human cells, it will improve the cognitive function in those affected.
            This discovery has the potential to have a remarkable impact on the world, because it could allow for those with Down syndrome to enhance their intellectual and interactive skills. In the United States alone, 400,000 people have been diagnosed with Down syndrome, including another six million worldwide along with the families and loved ones of these people. This study is specifically significant because it is among the first to explain a possible explanation and solution for the poor cognitive skills in people with Down syndrome, since the physical health problems of the disorder, specifically involving the heart, are now able to be treated. In the future, it can potentially slow the aging of humans with this affliction, along with preventing early onset Alzheimer’s. On a larger scale, this study shows humans, whether or not they have Down syndrome, just how vital stem cell regeneration is to human cognitive and physical function. Also, if the therapies performed on the Ts65Dn mouse translates with similar, positive effects on humans, it has the capability to improve the quality of life of six million people throughout the world.
            This article was successful in providing the medical and biological aspects of Down syndrome, along with formulating the results of the research of the study into a solution that the researchers believe will show cause and effect: by reducing the expression of the Usp16 gene, cognitive function in people with Down syndrome will improve. However, the study failed to indicate what specific drugs will be able to perform such a task, in addition to whether or not there were any negative side effects that the Ts65Dn mouse received from hiding the expression of one of its Usp16 genes. Therefore, the article would have made a stronger argument if it included any contradictory claims from other scientists who believe that ceasing the expression of a copy of a gene in a chromosome will have unforeseen negative impacts on the subject’s health, or whether or not other scientists have supported and agreed with the results of this study. This article only expresses the reports of the researchers working with the Stanford University School of Medicine, as well. All in all, the author of this article, Krista Conger, was able to synthesize the complex biological components of a complicated disorder into a concise explanation, making it able to be understood without being too simplistic. This is important because many people reading this article will be able to perceive the possibilities that the success of this study will offer to people living with Down syndrome.



A Quest For Resilient Reefs

Biology D Block Even Emma Lewis
Current Event- Ms. Davies 10/30/13

Lippsett, Lonny. "A Quest For Resilient Reefs." Whoi.edu. Oceanus Magazine, 4 Oct. 2013. Web. 25 Oct.      2013. <http://www.whoi.edu/oceanus/feature/a-quest-for-resilient-reefs>.
        This article stresses the threat that the ocean’s changing chemistry poses for coral reefs. It focuses on one specific scientist, Anne Cohen, and her thoughts on what should be done about this threat. However, first, the article goes into great detail about where coral reefs come from and their interaction with the ocean. Coral reefs come from a small organism called a coral polyp. They look very similar to a sea anemone, and are actually related to them. Thousands of these coral polyps perform one job, and its products make up the coral reef. This job is to take calcium ions and carbonate ions from the seawater, and combine these ions to make a mineral called calcium carbonate. There are different forms of calcium carbonate, coral polyps making a unique form called aragonite. Since there are thousands of them which perform the task rapidly, the aragonite crystals are combined to make massive, diverse and colorful structures. Normally, corals build the reefs at about 240 micromoles per kilogram of water. Scientists question how the coral polyps have the ability to make such structures, since each coral reef is unique.
        Consequently, the change which has started to occur in the ocean is a drop in carbonate ions. Before, when there was a stable level or carbonate ions, corals had the ability to adapt to any slight changes when building the reefs. However, the article noted that since the Industrial Revolution, the increased burning of fossil fuels has sent more carbon dioxide into the atmosphere. This gas is then diffused into ocean water, causing the water to be more acidic. This is because it reacts with the hydrogen ions, which lowers the pH in water. This ultimately causes a significant drop in carbonate ions, which is only continuing to decrease as we burn more fossil fuels. Next, the article explains why a drop in these ions is so important to the coral reefs. Its explanation was that there aren’t enough ions for the corals to build and therefore the aragonite crystals change shape and mutate. By this occurring, the reef fishes are at a higher risk of being a prey and the reef at a higher risk of being smothered by algae. On the contrary, there have been accounts of coral reefs that actually thrive in acidic conditions. Among them are the reef communities in the Palauan Rock Islands, which are still developing the unique coral structures, despite the acidic levels. Scientists have no idea how these coral reefs are going about this, but multiple tests are underway to discover the inner workings of the coral polyps.
  This article, although related to marine life, has a significant impact on myself and society. The coral reefs are a major tourist attraction; millions of people travel each year to scuba dive or snorkel to experience the greatness of these reefs. Although they make up only one percent of the ocean seafloor, they are home to about 9 million species. Among these species are coral fish, which represent 25 percent of the total fish that are consumed by humans. Thus, the depletion of these coral reefs would considerably hurt the human world, not just the maritime world. This is one of the reasons why I chose this article. It was interesting to me how tiny, small organisms could generate these enormous reefs and how these enormous reefs can even affect humans. The ties between the marine and human world are closer than I expected. Plus, it surprised me how the article mentioned that conservation organizations and the government are banding together in efforts to protect the coral reefs. This is yet another example of how the marine and human worlds are connected.
        The article was written in a factual tone and prompted the body of the article by posing questions. This gave the reader a very clear understanding of what the article was discussing; especially the cause and effect of the oceans dropping carbonate ionic levels. However, the article was almost too factual, conferring facts about science that an average reader would be confused by. For example, the article explained how aragonite crystals were made by the coral polyps and how they mutate when the carbonate ion levels drop. However, most readers do not know how the crystals form or why the crystals mutate. In addition, the article could have been shortened to avoid redundancy. In the beginning, the article mentioned the human benefits of coral reefs. Then, the article mentions the ultimate goal to preserve the coral reefs. Since both are discussing the human-side of the issue, they should have been combined to give the reader a better understanding of the article. Nevertheless, the article did a good job of explaining the cause and how effort must be made to preserve these magnificent coral reefs.

Wednesday, October 30, 2013

Blooming life under the Arctic ice


Emme Kerj
"Beneath Arctic Ice, Life Blooms Spectacularly." : Oceanus Magazine. N.p., 7 June 2012. Web. 30 Oct. 2013.
Life is blooming under the Arctic ice
         Phytoplanktons are microscopic organisms that use the photosynthesis. They cannot be seen with the naked eye unless they are gathered in a large number, which makes them look like a green blanket over the water. Because they obtain their energy from the photosynthesis, they must live in bright-lit areas, such as the water surface of a lake or sea. Phytoplanktons have before been thought to not be able to survive under ice until a team of scientists made a recent discovery. The team of scientists observed that the water beneath the ice contained high levels of chlorophyll that is rarely observed even in the most productive oceans (article). Chlorophyll, being crucial for photosynthetic plants, was not expected to be found in large amounts under the ice. The results that the team of scientists got was that the amount of phytoplankton produced under ice was four times larger than the amount in ice-free waters (article). The ice has worked as a magnifying glass for the sunlight, enabling the light to penetrate the thick ice layer. Emily Brownlee, a graduate student on board of the oceanographic research cruise observed that the phytoplankton was growing twice as fast under ice than on the surface of open oceans (article). Bob Pickart, WHOI physical oceanographer, explained that easterly winds churned out by wonder storm systems along the Aleutian Islands could reverse the current along the shelf break. The change is circulation drives cold, nutrient-rich water up from the abyss and refreshed the supply of nutrients available to phytoplankton growing near the surface (article).
         The discoveries made by these scientists prove that there has been a slight climate change along the Arctic Circle. Earlier studies had shown that the levels of chlorophyll, which phytoplankton contain, was minimal in water under ice. Not only was the amount of phytoplankton different but their examination of the bloom also showed that it was not caused by fallout from algae growing on the ice, but rather it contained different organisms that seized the confluence of currents, light, and nutrients (article). The nutrients in the Arctic waters have changed or been added to, which could change the whole ecosystem living in those waters.
         Overall the article explained the discovery very well and compared it to earlier studies. It made the change in phytoplankton bloom clear to the reader. I would have liked more background information about phytoplankton and chlorophyll in the article because it would have made some of the topics clearer. It made a clear point that there had been a large change in bloom but not why it was relevant to science.

Friday, October 25, 2013

How is Fukushima’s Fallout Affecting Marine Life?


Brendan Forst

How is Fukushima’s Fallout Affecting Marine Life?
By David Pacchioli

Summary:
            Following the nuclear disaster at Fukushima, cesium-137, cesium-134 and  iodine-131 were released in large quantities into the surrounding coastal waters. These radioisotopes are being spread throughout the marine food chain. The spread of these isotopes begins with the microscopic plants called phytoplankton. These plants absorb the radioactivity from their surroundings. The phytoplankton are eaten by zooplankton, which are eaten by small fish, and the trend continues along the chain. When the chain reaches the larger fish, some of the radioisotopes are actually released through excretions, which fall to the seafloor. From there the sedentary excretions are clumped together and sometimes eaten by bottom feeders. Now, the entire marine food chain has been affected with these synthesized radioactive chemicals, beginning with the tiniest phytoplankton.
            How drastically each member of the marine food chain is affected by the radiation is determined by a few other factors: the length of exposure, the size and species of the organism, the radioisotopes involved, the temperature of the water, how much salt is in the water, the amount of oxygen in the water, and a few others.
            Some radioisotopes are naturally occurring in ocean life, and present inside many marine organisms. These radioisotopes are non-lethal, for the most part, and don’t affect the fish. When radioisotopes from an outside source are added to the ocean water, that is when the problems occur. Unlike the naturally occurring radioisotopes, the added ones mutate and cause birth defects in the fish, not to mention that they last for a hundred years or more.

Relevance:
            The ongoing leakage of radioactive water into the marine habitat in Japan is affecting not only marine life close to shore, but effects are also starting to be noticed along the west coast of the U.S. Japanese fishing communities are being driven out of business because not many customers are thrilled at the prospect of radioactive fish. Not only are the Japanese fishers feeling the impact of this crisis but also, due to the ocean’s currents, the radioisotopes are being spread out across the world.

Critique:
            Although very informative, this article contained some parts that were not that straightforward. For example, the article states that radioisotopes can be “remobilized into the overlying waters through microbial and chemical processes.” Nowhere in the article does it explain what these processes are, or what they entail. Another thing I thought could have been constructed better was the title. Unlike what the title says, the article never once mentioned the affects of radioactive fallout on marine life, other than the fact that it became present in their habitat. I think a more accurate title would be, “How Is Fukushima’s Fallout Entering Marine Organisms?” This title would give the reader a clear idea of what to expect in what they read next, unlike the current title. All in all, I thought this article was a very interesting one that just needed to be explained a bit more.


Citation:
Pacchioli, David. "How is Fukushima’s Fallout Affecting Marine Life?" Oceanus Magazine. Woods Hole Oceanographic Institution, 2-5-2013. Web. 20 Oct 2013. https://www.whoi.edu/oceanus/feature/how-is-fukushimas-fallout-affecting-marine-life.

Skull Fossil Suggests Simpler Human Lineage

Lauren Gray

Wilford, John N. "Skull Fossil Suggests Simpler Human Lineage." Nytimes.com/. New York Times, 17 Oct. 2013. Web. 20 Oct. 2013.


For years, scientists have found remains of species that are believed to be part of the human’s evolutionary line. Each new skeletal piece is has been believed to be a completely different species. Now, after studying a new skull that was discovered 8 years ago, this theory appears to be inaccurate. A new theory has surfaced that, just like humans, species of hominids can each have individual bone structure and facial features. The skull was discovered in Dmanisi in Georgia along with 4 other hominid skulls. These skulls were believed to belong to the same species of hominid, the differences between them were “no more pronounced than those between any given five modern humans” (pg 1).
This new skull has “primitive features: a long, apelike face, large teeth and a tiny braincase, about one size of that of a modern human being.” (pg 1) These features were unlike those of previously discovered. The size of the braincase disproved some theories that hominids needed a large brain to get out of Africa. The 5 skulls are believed to belong to the Homo evolutionary line, possibly Homo habilis or early Homo erectus. The skull discussed in this article is the most complete early Homo skull ever found.
The circumstances under which the skulls were discovered us also gives us clues into the lives of these hominids. They were discovered in caves, believed to have been dragged there as the pray of some large animal, such as a saber-toothed cat or a giant leopard. This means that early Homos had to live in fear of these animals, as prey rather than predators.
The discovery leads to many incites into evolution and the way that scientists study new specimens. For example, these skulls were discovered together. If they had been discovered in varying locations scientists might have pronounced them as being different species, but because they were found together they have been classified as being the same. This idea of varying facial features in hominids can rewrite the entirety of human evolution. Our evolutions could be much simpler than scientists previously anticipated. This particular skull shape also provided information about the amount of intelligence for the migration of our ancestors. It is interesting how one little skull can change the entire course of years of research.

I thought that this article was a great source of facts about the progression of our understanding of evolution, but some things were a bit lacking. I would have liked to have read more about what the previous theories were and why. I also thought that this article was very jumbled and covered a lot of topics in such a short article. I had to read it more than twice to fully understand it. The author jumped between topics a lot. I think that the author could have written this article in a much more organized fashion that didn’t make me feel like I was playing mental hopscotch. I liked the concept, which is what drove me to choose this article, despite how confusing it was to read.
There was an error in this gadget