Postzygotic Isolation

Submitted by ddoyleperkin on Fri, 02/22/2019 - 09:38

Prezygotic and postzygotic are important when attempting to understand how it is possible for two species that may live in the same area to coexist without mating. If two species do happen to mate and produce offspring, isolation still occurs. Postzygotic isolation occurs after an egg has been fertilized and an offspring has been produced. There are two major forms of postzygotic isolation: hybrid inviability and hybrid sterility. Hybrid inviability refers to the extremely low fitness of an offspring from two different species. This low fitness often leads to the death of the offspring, inhibiting the continuance of this potential new species. Similar to hybrid inviability, offspring is still produced with hybrid sterility. This offspring, however may have high overall fitness, but cannot mate because of sterility. This type of isolation can be seen in mules, the offspring of a horse and a donkey. While mules can survive perfectly fine, two mules cannot create an offspring.

Prezygotic Isolation

Submitted by ddoyleperkin on Fri, 02/22/2019 - 09:38

Prezygotic and postzygotic isolation are two separate ways in which species are disallowed from mating with one another and producing a fertile offspring. Prezygotic isolation refers to the prevention of the fertilization of eggs while postzygotic isolation refers to the prevention of the production of fertile offspring. There are multiple different ways species are isolated before the egg can even be fertilized. Habitat isolation is one of the most significant forms of prezygotic isolation. If two species do not live in the same habitat, there is no chance that an egg of one species will be fertilized by another. A similar prezygotic measure is mating season isolation. A species that mates in the spring will have no chance of mating with a species that mates in the winter. Mating season isolation ties in closely with behavioral isolation. The time of year that a species mates is certainly a behavior, but behavior is not limited to mating seasons. If a species has certain pre-mating rituals, another species may not be familiar with this ritual, making it very difficult for the two species to agree to copulate. Still, two species might have similar enough behaviors and similar enough mating times that there may be a chance that the two could mate. In this event, between certain species, there is something known as mechanical isolation. Mechanical isolation refers to the physical inability of two separate species to mate. For example, spiders have penises shaped specifically for spiders of the same species, similar to a key and a lock. It would be physically impossible for a spider of one species to mate with another.

PARP Inhibition

Submitted by ewinter on Fri, 02/22/2019 - 08:15

Similarly, PARP proteins (poly (ADP-ribose) polymerase) proteins are involved in multiple DNA repair processes and have been targeted through inhibition for the treatment of ovarian cancer. The PARP inhibitors that have been approved by the FDA have been shown to prevent breaks in single-stranded DNA (which have been affected by the BRCA mutation causing the onset of cancer) so that the enzyme PAR encourages the mitochondrial release of AIF; therefore leading to apoptosis of the cells affected by the cancer mutations. This therapy has been hypothesized to be combined with Bcl-2 inhibition, which is a family of proteins involved in regulating apoptotic pathways. The therapy hypothesized therapy focuses on PARP inhibition in conjunction with the increased inhibition of anti-apoptotic proteins from the Bcl-2 family, specifically BH3. The Bcl-2 inhibition therapy currently under clinical trial is the ABT-263 monotherapy, and has shown clinically significant results in competing with BH3 proteins for binding with anti-apoptotic proteins and preventing those proteins from inactivating pro-apoptotic proteins. In vitro, the combined therapy displayed increased caspase activity and encouraged the Bax/Bak apoptosis pathway (Yokohama, 2017).

The Relation Between Pigmentation & Chloroplasts

Submitted by sharrath on Fri, 02/22/2019 - 07:55

In this experiment, we concentrate on the absorbance rate of chloroplasts that have been extracted from two different leaves; spinach(Spinacia oleracea) and kale(Brassica oleracea var. sabellica). Usually during photosynthesis, NADP+ is reduced to NADPH however, in this experiment we use an artificial electron acceptor, Dichlorophenolindophenol(DCPIP). Using the DCPIP, allows us to fully monitor the photosynthetic rates of each of the isolated chloroplasts. Both spinach and kale have very distinctly different coloration; kale which has a much darker pigmentation and spinach which takes on a lighter green. Kale will result in a lower absorbance rate in comparison to the spinach chloroplasts because of this difference in coloration. Kale has a much darker pigment than spinach, which leads us to believe that this difference in color is associated with the amount of chloroplasts found in kale resulting in a higher rate of photosynthesis. A higher concentration of chloroplasts found results in a darker pigment, lower absorption, more electrons being transferred in the ETC and a higher rate of photosynthesis.

BH3 mimetics

Submitted by ewinter on Fri, 02/22/2019 - 07:27

Anti-apoptotic Bcl-2 family proteins have been the subject and target of multiple ovarian cancer therapies. BH3 mimetics, small molecule inhibitors, have been designed over the years for the inhibition of anti-apoptotic proteins in an effort to induce apoptosis of cancer cells. The most potent of these inhibitors that have been successfully used are Bad-like BH3 mimetics such as ABT-737 and ABT-263. These antagonist drugs bind with high affinity to Bcl-2 and Bcl-xL in order to upregulate apoptosis.


Draft: Methods Results

Submitted by aspark on Fri, 02/22/2019 - 05:04

There were some photographic differences between the two figures. Figure 2A showed more of the tree and foreground than shown in figure 1A. Figure 2B also showed more bark than in figure 1B, and the lichen in figure 1B occupied half of the photographed space, while the lichen in figure 2B occupied only one tenth of the space. Figure 2C also showed the full width and more length of the tree trunk compared to figure 1C. Additionally, in figure 1C the lichen is centered horizontally and vertically, while in figure 2C the lichen is located in the lower right region of the photograph. Figure 2C also has a red car in the background, along with an overall blue tint throughout the whole photo.


In terms of the figure layout, the dimensions and relative locations of the photos are identical. The white boxes in the upper left corners of each photo are also identical, except for a difference in font between the letters.


PP: Activation Energy

Submitted by aspark on Fri, 02/22/2019 - 04:46

Exergonic reactions are spontaneous, while endergonic reactions are not; however, it is not the free energy change that determines the rate of a reaction. The rate of a reaction is determined by the activation energy, which is the energy needed to reach the transition state between reactants and products. Reactions with higher activation energies have slower rates because fewer molecules have enough energy to reach the transition state. When the activation energy is lower, more molecules can easily reach the transition state, accelerating the reaction. Enzymes speed up reactions by lowering activation energies. They do so by stabilizing the structure of the transition state, which then requires less energy to be reached. Enzymes do not affect the free energies of the substrates or products, and they do not alter the equilibrium of a reaction. They simply allow equilibrium to be reached faster. Enzymes can enhance the rate of a reaction in many ways: forming favorable interactions in its active site, orienting two substrates to react, directly participating in the reaction, or strain the substrate bonds. Enzymes usually use more than one of these strategies to stabilize the transition state, lower the activation energy, and speed up a mechanism.


Draft: Methods Introduction

Submitted by aspark on Fri, 02/22/2019 - 04:36

The Methods Project has three goals: to practice writing the Methods section of a research paper, which is used by scientists to replicate the research described, to differentiate observations from inferences by writing the Results and Discussion sections, and to identify controls needed for an experiment. For my figure, I will depict the interspecific interaction between a tree and a lichen, an example of commensalism that is often overlooked in everyday life. The specific tree and lichen I will portray are on a busy street in Amherst Center, one that is walked past by students frequently.


In order to maintain strict consistency between the photos in both the original and replicated figures, I will have to set several controls described in the methods. I will control the time at which the photos are taken, in order to keep the lighting uniform, and the relative distance at which the photos are taken. I will also control the instructions for combining and labeling the photos to create the final multi-panel figure, specifying dimensions and coordinates.


Introduction Methods

Submitted by cbbailey on Fri, 02/22/2019 - 00:44

The goals of this project was to be able to construct a methods section was to be able to create our own multipanel figure on our own, to be able to create a methods section to explain how the figure was created, and compare our create figure with another figure created by somebody else following our methods. By analysing the differences between the two figures created from the methods we will be able determine what parts of the methods are unclear and require more detail to create an accurate replica. The subjects that I chose for my figure were the trees covered in Ivy branches. I chose this interaction since because both were plant species there was very little chance for there to be a significant change in a two week period resulting in the same specimen not being able to be photographed for the replicate figure. Also even if there had been some sort of problem resulting in the specimen not being usable for the replicate, there were many other examples alongside the road that could also be used. When selecting my specimen, I wanted to make sure that it had a thick layer of Ivy that covered a large area of the tree to make sure it was very noticeable in the figure.

Meaning of Home

Submitted by tokiokobayas on Fri, 02/22/2019 - 00:30

    For everyone, the meaning of home changes as they get older. As a child, home is where your parents and siblings are. As a young adult, it becomes the place where your significant other lies--and when you get older, the definition can lie basically anywhere. It doesn’t matter where or who or what, but inevitably we all have a place we can go back to. Yet what dictates the feeling of home? Why is it that we have that saying, but there isn’t a single word emotionally that can describe what that feeling of home is? Sure it’s warm, it’s happy, it’s safe, but most importantly none of these words completely encompass its feeling. Its location changes as we get older, and the people or person that it involves changes over time as well. Is it possible to have a home that doesn’t change, to the point where it’s stable and no matter who it is, can look at this said hypothetical thing and say “yes that is a home”.


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