Sweetened diets and processed foods have become common in the American diet with many different sugary substances present in multiple food sources; however, behavioral tests comparing the preferences for these different types of sweeteners are uncommon. In this experiment we analyze behavioral preferences of planarians to 3 different types of sweeteners. The three forms of sweetener observed are pure sucrose, pure brown sugar, and pure saccharin. The chemical formula for sucrose is C12H22O11 and in a similar experiment it was found that sucrose produces a rewarding effect in planarians (Ouyang @ all, 2017). The chemical formula for brown sugar is the same as sucrose however it has molasses present in it. While we hypothesis that similar results will be seen in sucrose and brown sugar it has yet to be seen if planarians have a preference between the two. Saccharin which is commonly referred to as sweet n’ low has a chemical formula of C7H5NO3S. Saccharin offers effectively no food energy but is however approximately 300-400 times sweeter than sucrose. While no experiment was done to show if planarians prefer saccharin the group is interested to see if the planarians have a preference for the artificial sweetener.
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Our poster tested sweetener preference, specifically looking at which sweetener was most favorable amongst planarians as marked by movement. According to our data, planarians most preferred cane sugar as they spent the most time directly on top of the cane sugar area, and when presented with two other sweetener options, over half of the time they continued to spend on cane sugar. We can use this data and planarians as model organisms to demonstrate that sweeteners typically attract organisms and are therefore more likely to be consumed.
Insulin resistance is the somatic cells’ inability to respond to the insulin hormone. As a result, these cells do not take in glucose from their surrounding environment. What results is an elevated level of glucose in the blood, which signals for the pancreas to release more insulin. Due to the continuous production of insulin and the cells’ inability to respond and take in glucose, hyperglycemia and hyperinsulinemia may result. The resistance to insulin results from a mechanism error in the signaling pathway. This could be a functional error in the receptor, the proteins within the cascade, or in the bodies immune response to the receptor.
Due to Matthew’s low quality of life and frequent metabolic crises, a liver transplant is recommended, despite the risk associated with surgery. A liver transplant could come from a healthy living donor (such as a relative) or a deceased donor and would provide enough supplemental enzymes to breakdown proteins associated with an unrestricted diet. While surgery is risky, due to the potential of infection and death during surgery, a recent study showed promising results. In this study, 35 patients suffering from MSUD received liver transplants. Of the 35 patients, 100% survived and liver function was normal in all patients. In addition, amino acid levels were corrected within hours after surgery. Patient survival for all 54 documented MSUD patients undergoing liver transplant remains at an impressive 96-98%. Even though the amino acid levels were corrected, other symptoms associated with MSUD could not be rectified. 1/3 of patients entering the study were mentally impaired (IQ<70) and no improvement was noted one year post surgery. Also, the recessive allele would not be fixed and therefore, should Matthew choose to have children in the future, he will have a 100% chance of producing a child that is a carrier, and potentially producing a child that suffers from MSUD as well. In addition, 40% of patients suffered from acute rejection of the new liver. Rejection occurs due to the immune system’s white blood cells recognizing the antigens on the donated liver as a foreign substance and therefore as a potential danger to the body. In response, the B Cells, which are produced in the bone marrow, produce antibodies that lock onto the antigens. At this point, killer T cells destroy the cells marked by the antibodies, which in this case would be the donated liver. In order to reduce the chance of rejection, Matthew will be placed on immunosuppressants for the rest of his life to reduce the activity of the immune system. There are several mechanisms by which immunosuppressants could repress the immune system, but most immunosuppressants work by reducing the proliferation of T Cells and B Cells through inhibiting genes that code for cytokine. The less cytokine is produced, the fewer T Cells are produced. Unfortunately, this makes Matthew more susceptible to other diseases (such as the common cold), which the immune system would normally be able to fight off using T-cells. Despite all the risks associated with liver transplant, Matthew could lead a relatively normal life and potentially stop restricting his diet and suffering from metabolic episodes if the transplant is a success. Therefore, without the liver transplant, Matthew’s only option would be to continue his current regimen, which is clearly not working considering he suffers from metabolic crises.
Matthew is currently suffering from Maple Syrup Urine Disease. MSUD is a recessive autosomal genetic disorder with mutations in the genes BCKDHA, BCKDHB, and DBT. In a non-MSUD child, the branched amino acids (BCAA) are transported into the liver cell by an L-transporter and converted into BCKA via the BCAT proteins, which is a reversible reaction (therefore they can be converted back into BCAA if necessary). It is then inside the mitochondria where the BCKAs are further metabolized and broken down by the BCKDH complex. A patient with MSUD has a dysfunctional E2 subunit of the BCKDH complex, which results in the patient not fully being able to break down the amino acids, causing a dangerous influx of BCAA in the bloodstream, which can result in neurological damage. Currently, in order to avoid high BCAA levels collecting in the body, Matthew is on a strict diet avoiding foods high in protein such as milk, eggs, and meat. Even with the restricted diet, Matthew is still suffering from metabolic crises due to elevated BCAA levels in his bloodstream, which could result in brain swelling, stroke, or sudden death.
The two hit hypothesis suggests that even though a tumor suppressor gene may undergo many mutations, most of the loss of function mutation are recessive. Therefore, individuals who may have been born with a mutation in the tumor suppressor gene only need to have 1 mutation in the other normal gene for cancer to occur (in Knudson’s experiment it was retinoblastoma). Thus, those who were not born with the mutation must acquire mutations on both genes to get cancer, which Knudson hypothesized would result in a later development of cancer. This hypothesis is supported by Knudson’s findings that those with bilateral hereditary cases were not only diagnosed at a younger age, but also showed a curve consistent with a single mutation process. Knudson also found that those who inherited a RB1 (tumor suppression gene mutation) would also have more than one tumor; however, those who did not inherit the mutation almost always only had 1 tumor.
Serial pathways are made up of single neurons connected with another neuron on the line. Serial pathways control posture and locomotion in addition to reflexes such as the knee jerk reaction. The serial pathways are used for rapid response. On the other hand, parallel processing allows an input to be spread to different neurons and therefore processed in different sections of the nervous system. Losing a pathway in a parallel processing system is less dramatic then losing a pathway in a serial pathway because the patient would not lose sensation completely, but rather lose one aspect of the sensation.
There are often many signal transduction proteins and pathways from one receptor molecule because this enables the cell to send the signal to more than one place in the cell. Also, if there are multiple pathways originating from a single receptor molecule, the cellular response can be amplified more efficiently, and a small signal can eventually turn into a large, significant response. In addition, different signal transduction pathways resulting from the binding of a single receptor molecule also allows for interactions between the pathways and what is known as “cross-talk”; when one or more parts of a signal transduction pathway affect another.
transcription factors: Transcription factors are proteins that bind to specific DNA sequences in order to regulate the expression of a given gene. . Transcription factors function through a wide variety of mechanisms. Often they are at the end of a signal transduction pathway that functions to change something about the factor, like its subcellular localization or its activity.
enhancers: Enhancers or cis-regulatory modules/elements (CRM/CRE) are non-coding DNA sequences containing multiple activator and repressor binding sites. Promoter-enhancer dichotomy provides the basis for the functional interaction between transcription factors and transcriptional core machinery to trigger RNA Pol II escape from the promoter.
Stem cells are classified as cells that can divide over and over and produce other stem cells and specialized cells; therefore, since the cells are continuously self dividing, there would be no need to continuously administer gene therapy. Gene therapy is important because it can treat the actual cause of a disease and potentially help fix genetic disorders for which we currently only have treatments that can target the effects of the disease, not the cause. Unfortunately, stem cell research continues to be a hotly debated topic as there are moral implications that raise questiosn regarding stem cell research.