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The epithelial to mesenchymal transition (EMT) allows cancer cells to begin the process of metastasis by unadhering to one tissue and migrating to another location. A major characteristic of this process is the loss of e-cadherin, which can result from the expression of multiple transcription factors including SNAIL, ZEB, and KLF8. EMT can also be induced by certain growth factor pathways as well as TGF beta and hypoxia. The researchers aim to target these transcription factors and signaling pathways as well as the hypoxic tumor microenvironment in order to prevent metastasis from occurring. If cancerous cells are unable to carry out EMT, the effects of metastasis should lessen. Subsequently, apoptosis-inducing therapy can be delivered to these now stationary cells. A region of interest for the researchers is aptamer-regulated exosomal therapy, where aptamers can serve as binding partners for these transcription factors and elements in these signaling pathways. This binding can inhibit the downstream effects, such as the induction of EMT. A cell suicide gene or cytokine such as TRAIL may also be incorporated into the interior of the exosome for targeted delivery.  

In the textbook and lecture, dopamine is described as a neurotransmitter involved in movement, attention, motivation, learning, and reinforcement. This article related to the motivational salience effect of dopamine as not only was the emotional pleasure of music compared to levels of dopamine, but the motivation to listen to the pleasurable music again was also measured. There is a common misconception that dopamine is the neurotransmitter responsible for pleasure. In fact, dopamine is more involved in mechanisms that can lead to these pleasures, especially motivation, learning, and reinforcement.

Although levels of dopamine have an impact on motivation and musical pleasure, I am curious as to what exactly causes this pleasure. Do the sound waves of the music stimulate a specific signaling pathway that leads to these effects? I know some music sounds “sad” and some sounds “happy;” exactly what in the music leads to us biologically establishing these connotations, and how do they affect levels of dopamine?

Dopamine is a neurotransmitter involved in pleasure, reward, and motivation. In this study, researchers manipulated dopaminergic synaptic availability through the use of three substances: levodopa, risperidone, and lactose. Levodopa is a dopamine precursor that increases dopaminergic availability. Risperidone is a dopamine antagonist that reduces dopamine signaling. Lactose was used in this study as a control. Electrodermal activity was used to measure changes in pleasure and reward while listening to music, which included the participants’ favorite songs as well as ten other singles. Participants rated songs in real time based on pleasure as well as monetary value (how much money they would pay for the song). Results showed a causal link between levels of dopamine caused by the drugs given and emotional pleasure. Participants given levodopa gave higher emotional response ratings than compared to the lactose placebo and were more likely to spend money on the music they were listening to. Those given risperidone were unable to experience chills, an emotional pleasure response, and gave lower emotional response ratings compared to the placebo. They were also less willing to spend money on the music, indicating a weaker motivation to listen to the music again.

https://neurosciencenews.com/dopamine-music-10628/

Tumors become metastatic when they leave their primary site of development and travel throughout the bloodstream to start new growths over the body. This can lead to complications in treatment as it is challenging to eradicate the tumor completely if it is mobile. Metastatic ancer cells also have the ability to modify their genomic expression patterns. This allows them to behave like stem cells, remain quiescent, and express a broader range of genes to further their survival. They are also then able to differentiate into a different cell type at any moment. This lack of consistency in cell identity renders metastatic cancer difficult to fully treat. Metastatic cancer cells can also create an environment known as the premetastatic niche, an environment where the cancer can modify to its advantage and eventually spread to. These cancer cells additionally have the ability to induce angiogenesis in other cells in order to maximize nutrient flow to their population and increase their survivability.

The overall sizes of each figure are different: Figure 1 is 1200 pixels while Figure 2 is approximately 600 pixels greater. Despite consistent orientation of panels across both figures, the dimensions of each panel differ. Letter labels are lowercase in Figure 1 and uppercase in Figure 2. The white backgrounds behind each letter also vary in size between the two figures and are smaller in Figure 1 than in Figure 2. In Figure 1, letter labels are centered within their respective white backgrounds whereas in Figure 2, the letter labels are not centered. The white backgrounds themselves also differ in shape across both figures. In Figure 1, the white backgrounds are square and in Figure 2, the white backgrounds are rectangular. Figure 2 also has green borders around each white square letter label, an element Figure 1 does not have. Image quality differs between the two figures with clearer images in Figure 1 than in Figure 2. The images in Figure 1 also take up the majority of the frame whereas in Figure 2, there is more background space in the images.

The backgrounds of Panel B in both figures differ. In Panel B of Figure 1, the individual Duck is standing on ice. In Figure 2, the individual Duck is standing on muddy terrain. The Duck in Figure 1 is oriented towards the camera whereas the Duck in Figure 2 is oriented away. In Figure 1, the Duck is set more into the foreground of the panel than the Duck in Figure 2. The length and width of Panel B in Figure 1 is longer than those of Panel B in Figure 2.

In Panel A of both figures, the individual Goose is standing on snow. However, the backgrounds of Panel A in each figure differ. In Figure 1, the snow is the only background element visible. In Figure 2, there are other Geese and a tree in the background. Additionally, the Goose in Figure 1 is looking at the camera whereas the Goose in Figure 2 is eating. In Figure 1, the individual Goose is set more into the foreground of the panel than the Goose in Figure 2. The length of Panel A in Figure 1 is also longer than the length of Panel A in Figure 2. The widths of this panel across both figures is consistent.

The imaging software used to create the figures may also account for the difference in many factors between them. Figure 1 was created through Inkscape and Figure 2 may have been created through Microsoft Word. Image size differences may be explained by software as Word limits the margin sizes to one inch by default, whereas in Inkscape, the images are not bound to any range. This also explains the letter label sizing, as font size 70 in Inkscape appears differently than font size 70 in Word. Word also does not have the same centering functions of the letter labels as Inkscape, also accounting for this difference between the two figures. Discrepancies in arrow shape and size are also explained by this software difference. In Word, arrows appear blue with a large width by default. In Inkscape, one can edit the arrow color and width. The arrowheads are also different as Inkscape offers a variety to choose from of different ang while Word has the singular arrowhead of 90 degrees. The black line in Panel C and green backgrounds of images in Figure 2 may also be remnants from Word imaging that Inkscape does not possess.

The methods section of a scientific article allows researchers to determine the validity of a study based off of replicability. When developing an experiment, certain factors that may affect the replicability of a study should be controlled in an effort to minimize discrepancies between iterations. The Spring 2019 methods project in Dr. Brewer’s Writing in Biology class at the University of Massachusetts Amherst attempts to practice and develop these skills, as well as distinguish between observation and inference through the examination and replication of a multi-panel figure illustrating an interspecific interaction.

A lack of zoom on a camera may explain the image quality differences between the original and replicate figures. Perhaps there was not enough time to borrow a camera and SD kit from the Digital Media Lab or perhaps all the cameras were already checked out at the time of replication. Ducks and geese are also mobile, unpredictable creatures. It is impossible to ensure the ducks and geese will be in the exact location they were at the time of initial imagery, or that the weather conditions will be the same. This can explain the differences in the backgrounds of each image for both the original and replicate figures.