Elevator Speech

Submitted by samihaalam on Sat, 12/09/2017 - 00:26

Planarians exhibit the rare ability to regenerate their entire heads and central nervous system after being cut off. We also knew that an excess of salt can have a harmful effect on living tissues, so we wanted to observe the effects of different salt concentrations on the regenerative abilities of planarians. We cut the heads off of planarians, and then put the tails in different concentrations of salt. The control had no added salt, the low concentration had 1 gram of salt, and the high concentration had 2 grams of salt mixed into small water bottles. There were 3 planarians for each concentration. We measured the length of each planarian 3 days a week for 2 weeks. Our hypothesis was that higher salt concentrations would lead to a slower regeneration rate of the planarian head. Unfortunately, the planarians in both the low concentration and high concentration salt water died before we returned from Thanksgiving break, so we could not observe any growth in them. So, our results were inconclusive. Further studies at a lower, more precise concentration of salt are needed to fully observe the impact. 

Topics in Plant Bio Notes - Light Perception

Submitted by samihaalam on Fri, 12/08/2017 - 23:59

The mistletoe tree can get invaded by parasitic bushes. The Vikings used to think that these were a sign of good luck, ass they would be green plants in the winter, but they are in fact parasites. About 4000 biotrophic plant species are parasites. These plants have lost their ability to perform photosynthesis, and so they parasitize. For example, the species Striga can produce up to 500,000 seeds that sense roots of other plants, and germinate and grow towards. Plants convert sunlight into energy, which is processed through photosynthesis. Certain information is considered about the sunlight, such as he quantity, quality, direction, and photocycle about the sunlight. This leads to photomorphogenesis in the plant, which is all the different types of responses in the plant to the light. 

Photomorphogenesis is light-mediated regulation of plant growth and development. This involves the proccess of de-etioation, which is the transition from dark to light grown seedlings. It is characterized with the plant having short stems and there is an initiation of green leave and internodes. On the other hand, skotomorphogenesis is the development of the characteristic growth and appearance of plants grown in the absence of light. The plants in this category are characterized by etiolation, which is when th plants have exaggerated, long, spindly growth, pale color due to a lack of chlorophyll, and stunted leaves. Photoreceptors detect light of different wavelengths. A photoreceptor is a pigment in a protein that initiates a signal-transduction cascade when exposedd to light of a specific wavelength. Cryptochromes and phototropins respond to blue light. Phytochromes respond to red and far-red light and include phyA, phyB, phyC, phyD, and phyE. They can induce a photoreversible response. This means that red light stimulates growth, while far-red light inhibits growth in plants. This can be seen in lettuce seed germination. 

SOD1 disulfide bond

Submitted by msgordon on Fri, 12/08/2017 - 21:27

Molecularly, SOD1 is unusual in that it is primarily a cytosolic and mitochondrially localized protein, but yet it contains a stable disulfide bond - such proteins are rare because the cytosol is a heavily reducing medium. This led many researchers to incorrectly postulate that mutations in the protein disrupted the disulfide bond which subsequently impacted the enzymatic activity in a negative manner, producing the ALS phenotype (Sea et al. 2014). However, the results of recent studies suggest that it is not a loss of function mutation that is responsible for ALS, but rather a toxic gain of function mutation that is independent of its normal enzymatic activity (Brujin et al. 2004).

Atlantic Salmon

Submitted by danielcosta on Fri, 12/08/2017 - 18:35

The Atlantic Salmon population in the river systems of New England, especially Maine, have declined rapidly since the 1960's. This rapid decline is due in large part to the effects that human urbanization has had on these river systems. Disturbances to the environment, like clear cutting forest patches and the construction of dams, have degraded the water quality of these rivers tremendously. Unloading of logs and sediments into the river made the chemistry balance of the rivers unfit for the salmon. Construction of dams has put physical barriers in the path of salmon migration to and from the rivers to the sea. These factors added in with the exploition of salmon for commercial use has greatly damaged the salmon population, possibly beyond repair. 

Ecology Assignment

Submitted by jgcahoon on Fri, 12/08/2017 - 15:17

 In order to have the lowest possible risk of exposure to the contaminants, a species in this food web would need to hunt those individuals in the 3rd trophic level that are older, or possibly individuals in the 4th trophic level that are generally younger. The organisms in these trophic levels contain a little bit of contamination, but not nearly as much as the organisms in the 5th trophic level. The reason I say those individuals that are older in the 3rd trophic level is because as an organism gets older, it accumulates more contamination. The older individuals in this level will contain some contamination, but still provide benefits for the consumer. The 4th trophic level on the other hand has a moderate level on containment, so consuming those that are younger in the trophic level will accumulate less contamination Of course, this individual can still eat primary producers and primary consumers (1st and 2nd trophic levels), as they possess less contamination. 

Elevator Speech

Submitted by hamacdonald on Fri, 12/08/2017 - 12:53

 

In our experiment we tested caffeine amount on planarian regeneration. In order to have just caffeine and water without any other possible ingredients we ordered Water Joe. All of the nine planarians were measured, cut in a half, and measured again. We had a control group of planarians that had no caffeine and were placed in Nestle water. The moderate amount of caffeine had 10 mL of Water Joe and 10 mL of Nestle. The high amount of caffeine had 20 mL of Water Joe and no Nestle. We found the control group grew the most, then the moderate amount, and the high amount of caffeine killed all three planarians. These results make sense as these are freshwater planarians who likely do not come in contact with caffeine and their bodies did not know how to survive in large amounts of it.

ALS SOD1 protein

Submitted by msgordon on Fri, 12/08/2017 - 12:44

The SOD1 protein itself is a homodimer and is normally localized to the intermembrane space (IMS) between the inner and outer mitochondrial membranes as well as the cytosol. Structurally, the protein is comprised of two β-barrel subunits that each contain bonding sites for copper and zinc ions (Sea et al. 2014). When it is first trafficked into the mitochondria the protein takes on an immature form, lacking the metal ions necessary to carry out its function. After binding, it remains in the intermembrane space with aid from the copper chaperone protein CCS. The enzyme then uses the aforementioned ions to catalyze the conversion of otherwise toxic superoxide radicals into water and hydrogen peroxide - which is broken down further by catalase (Estacio et al. 2015). It has been proposed that the SOD1 protein uses the copper cation to extract the extra electron from the superoxide radical, effectively converting it into molecular oxygen. Similarly, the presence of the cations are crucial to its function as the positive charges aide in attracting the negatively charged superoxide anions.

 

Korsakoff's syndrome- #3

Submitted by jjaneiro on Fri, 12/08/2017 - 12:19

Substance abuse disorder is a categorized disorder in the Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-5), published by the American Psychiatric Association. Depending on the substance being abused, there is increased risk of developing other serious diseases. One such syndrome is Korsakoff’s syndrome, which is seen in long-term abusers of alcohol. This syndrome is categorized by individuals developing anterograde and retrograde amnesia as a result of developing lesions on the brain. These lesions arise from the depletion of B-vitamins, specifically thiamine, in the brain. Anterograde amnesia is a type of amnesia in which the individual is unable to form new memories or remember new information, yet his or her long-term memory remains intact. Retrograde amnesia, on the other hand, is just the opposite. Individuals with retrograde amnesia cannot remember long-term information, even their own identity. Because of the seriousness of this syndrome, with the inclusion of substance abuse disorder in the DSM-5, it makes it easier for people struggling with substance abuse to receive the psychiatric help to overcome their addiction. This is especially critical for preventing the development of illnesses and syndromes associated with long-term substance abuse, such as Korsakoff’s syndrome.

 

Article 6 Summary Continued

Submitted by brdougherty on Fri, 12/08/2017 - 11:25

The results of this experiment showed that the lactate concentration in the blood while basking did not change when compared to previous lab experiments. In foraging Iguanas it was found that the average blood lactate concentrations was 1.55 + 0.55 umol/m. In the forced running experiment the lactate levels were found to be similar to those found in previous lab experiments and they continued to increase even after they stopped running. When the iguanas were forced to dive their blood lactate levels increased and continued to increase even while they were cruise swimming after the dive. However, it was observed when the iguanas were not disturbed to draw blood when diving and the allowed to free swim there lactate blood concentration eventually started to decrease during swimming. Through these results Gleeson concluded that the marine iguanas were very similar to other species of lizards and usually only transition to anaerobic energy production during burst activities that may be considered stressful. 

Elevator Speech: Perfect Paragraph

Submitted by brdougherty on Fri, 12/08/2017 - 11:05

In this experiment I examined if planarians had a preferential behavior for a particular sweetener. The 3 sweeteners observed were sucrose, brown sugar, and saccharin. The way this was tested was by putting the 3 different types of sweeteners in a petri dish and allowing the planarians to move freely between the sweeteners. The results show that sucrose was the most preferred sweetener followed by saccharin, and then brown sugar. The results were rather interesting because sucrose and brown sugar have the same chemical structure besides the fact that brown sugar has molasses. At the same time saccharin offers no nutritional value yet it was more preferred than the brown sugar. This observation made the group hypothesis that molasses may have properties that deter planarians. This hypothesis should be tested farther to see if it is the reason why planarians least preferred brown sugar. 

Pages

Subscribe to Writing in Biology RSS