Submitted by jiadam on Tue, 04/25/2017 - 11:16

How is DNA replicated?

There were three postulates as to how DNA was replicated. The first was semi-conservatively where both strands of DNA are used as template to to 2 new replicated strands. In this methods, in each new helix, one would have the parent template strand and a newly synthesized daughter strands. The conservative postulate was that both strands were used as DNA templates and as soon as replication was completed, the template strands would return to each other and the newly synthesized strands would form a new helix that has no old DNA. The last postulate was dispersive, where DNA is split into different pieces due to unwinding a double helix would cause too much supercoiling and tension at the far end, The DNA would get replicated and put back together with a mixture of parental and daughter DNA interspersed with each other. It was proven that DNA was replicated semiconservatively by Meselson-Stahl.

March for Science

Submitted by mduque on Tue, 04/25/2017 - 11:04

The March for Science was organized in response to widespread alarm regarding the attitude of President Donald Trump's administration toward science. Trump has repeatedly called global warming a “hoax” and promised to change environmental protection laws. In March, the White House released a budget proposal that included massive cuts to the Environmental Protection Agency and the National Institute of Health. Since then, many scientific societies and advocacy organizations endorsed a march. On Saturday April 22nd, tens of thousands of people gathered in Washington DC, and in at least 600 other cities around the world, making this one of the largest demonstrations in support of scientific research in history. 

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Submitted by mduque on Tue, 04/25/2017 - 10:21

Immunotherapy is a type of cancer treatment designed to boost the body's natural defenses to fight cancer. It uses substances either made by the body or in a laboratory to improve or restore immune system function. Instead of using chemotherapy to target cancer cells, immunotherapy helps the immune system work better at destroying cancer cells without affecting healthy ones. There are several types of immunotherapy including the use of monoclonal antibodies, non-specific immunotherapy, oncolytic virus therapy, and t-cell therapy.

Journal 33

Submitted by kngallant on Tue, 04/25/2017 - 09:21

    Your current social status is influencing more than just your psychological well-being, but it also has physiological effects, determining how healthy you are. Being low on the social ladder can have a negative effect on the immune system. This has long been known, however there have been many questions about the biological mechanisms underlying these effects - until now.

A team of researchers turned to social groups of female rhesus macaques to answer these questions. Rhesus macaques are monkeys that live in hierarchical social groups, and are often used as a model to study the links between social status and physiology. Experimenters manipulated social rank by introducing monkeys into a new social group, and the order in which they were introduced determined their social rank - the first monkey introduced had the highest rank, and the last introduced had the lowest.

The researchers then drew blood from each monkey, and from the blood they purified immune cells called peripheral blood mononuclear cells (PBMCs). They measured gene expression levels in these cells to determine if variation in gene activity can be explained by social rank. They found 987 such genes, 535 of these genes were more highly expressed in higher ranked monkeys, and 452 of them were expressed more highly in lower ranked monkeys. This is significant because it shows that social rank is associated with gene activity in immune cells.

Furthermore, they found that dominance rank changes genes in such a way that just looking at gene expression data alone was enough to predict the monkey’s social rank with 80% accuracy. These findings prove that it is social environment that has an effect on gene expression, and not the other way around. However, they also found that this effect isn’t permanent - when a female monkey switched ranks, her gene expression levels did as well.

These differences in gene activity require certain regulatory mechanisms. The team of researchers found that variation in the expression levels can be partly explained by differences in tissue composition of each monkey. Variation in glucocorticoid (a type of hormone) regulation is another mechanism found that may account for the relationship between social rank and gene expression levels. There were also DNA methylation differences between different social ranks, suggesting that epigenetic changes might also be at work.

These findings are important implications, because they likely apply to human beings as well. This supports the idea that having a negative social environment may increase chances of infection and disease. But again, this effect is reversible - improving your social environment will have a positive impact on your immune system and overall well-being.

Journal #35--Peer Review Fraud

Submitted by skhall on Tue, 04/25/2017 - 08:08

   On Facebook today I saw an article that someone had shared about cancer papers being retracted for fraud through peer reviews. The authors that published such research papers (107 to be exact) faked the peer review process. Apparently this isn’t the first time this journal has done this. Last year, 58 of the journal’s papers were retracted from 7 different journals…for the same reason. . "There is some evidence that so-called third-party language-editing services play a role in manipulating the reviewing process,” said a spokesperson. The argument is whether they let it go knowing the the authors most likely knew what they were doing. However some believe they can get away with it because there’s most likely nothing wrong with the research, it just hasn’t been peer reviewed. “It is unclear whether the authors of the manuscripts were aware that the agencies were proposing fabricated reviewer names/e-mail addresses.” This recent fraud was noted when there happened to be an extra screening of the journal. I find this process interesting because I would think that these journals doing the publishing and editing would notice that this group has had issues with this in the past. If they are not willing to take the time to work through their writing and make it valid for the readers and further journals, why are they doing all of this work?

Landscape Ecology

Submitted by kmichaud on Tue, 04/25/2017 - 01:03

When examining natural landscapes that I am familiar with, the patch of conservation land designated as the Mount Pisgah Conservation Area in my hometown of Northborough, Massachusetts comes to mind. This particular patch spans 83 acres across the towns of Northborough, Berlin, and Boylston. As designated conservation area, the patch is free of roads for car traffic while roads outline the edges of the conservation area on most sides. The patch is irregularly shaped with rather pointed edges in an overall rectangular shape. Though it is bordered by relatively forested areas, surrounding patches of woods are speckled with housing developments and farmland properties resulting in a loss of overall connectivity between patches. The Eastern edge has a relatively steep slope compared to the surrounding patches, but is not nearly steep enough to restrict passage of most terrestrial organisms. The vegetation is predominantly deciduous forest with smaller patches within monopolized by low hanging conifers. These patches are directly East of the steepest sloping areas where the major wetland areas can also be found.

Meet your new coworker:

Submitted by eriklee on Mon, 04/24/2017 - 22:52

Baxter is a $25,000 humanoid robot designed by Rethink Robotics. The company’s goal is to design robots that combine human psychology and robotic engineering together. By doing this, the company intends to create smarter robots with the ability to learn from humans and complete repetitively mind-numbing tasks. Baxter is described as a female robot named after female bakers. John Bohannon tested Baxter by instructing her to move objects from a crate to a conveyor belt. To do this, John had to grab the robots hand a transfer an item from the crate to the conveyor belt. Additionally, he had to outline boundaries for the starting and stopping destinations. Baxter is capable of repeating the task after the first demonstration with one drop.

            Beyond completing repetitive tasks, Baxter is programmed to display six emotions ranging from tiredness to surprise. These facial expressions are shown on a monitor displaying digital eyes. The robotic arms and body shift to match the expression. The designers hope to improve safety and improvisation within robots to make them behave like humans. There are several monitors and switches that protect the robot from accidentally or intentionally harming a human nearby.  However, the improvisation has been limited as there needs to be more work on what psychologists call the Theory of Mind. Furthermore, Baxter and many other robots have limited mobility, especially upstairs.

Link to Article:

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Submitted by kngallant on Mon, 04/24/2017 - 18:41

    Gray bees are unique because they exhibit a mating behavior that is not seen in most other species of bees. Female grey bees burrow in the ground to build nests for their offspring. The males will then search for these nests, and dig into them to find emerging virgin females to mate with. This is unique in comparison to other species, because normally the male bees search for mates while visiting flowers. The reason gray bees exhibit this behavior is because female gray bees can only reproduce once in her lifetime. After this, she is no longer sexually receptive. Therefore, male gray bees must find virgins in order to pass their genes along, which is most easily done at nesting sites, where young females first emerge.

Journal 32

Submitted by kngallant on Mon, 04/24/2017 - 18:40

    Lemmings are small mammals that live in the Arctic. Lemmings often kill themselves by jumping off cliffs. It was originally thought that they do this to regulate population size when there is overcrowding. This is a group selection hypothesis. Group selection is the idea that groups or species have individuals that self-sacrifice in order for the survival of the species. However, this is unlikely, because individuals do not exhibit behavior that is costly. It was eventually found that the lemmings are doing this for their own benefit, not to regulate population size. When populations get dense, some lemmings will leave their group to seek more food and reduced competition. Sometimes, they accidentally kill themselves when leaving the group by going off of a cliff. So, the suicidal behavior is not done on purpose, it is an accident resulting from leaving the group to seek new resources.

Immunology PP

Submitted by amprovost on Mon, 04/24/2017 - 15:14

When an infection is spread, it is initally attacked by macrophages, which are also known as guard cells. These huge cells are the first to respond to an infection, and operate by using phagocytosis to ingest enemy organisms. These cells are larger than most human cells, and on average can ingest roughly one hundred bacteria per cell. Once ingested, these invaders are stored in a membrane until they can be degraded by enzymes from the macrophage. Macrophages also cause an influx of water from the bloodstream, which results in the swelling that we see around an infection. If the macrophages are unable to destroy the infection alone, they release messanger signals into the blood stream calling for backup. The next line of defense is the neutrophil. These cells are so deadly that they are saved for serious infection, as their attacks are somewhat indiscriminate that they also damage host cells. These cells also only have a lifespan of 5 days, as if they accumulate they can cause serious damage to the host. 


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