Philodendron bipinnatifidum

Submitted by matjbaker on Fri, 03/10/2017 - 10:56

    There is a plant in the pond room of the Durfee Conservatory labeled

Philodendron bipinnatifidum. It is on the right hand side of the pond when entering from the Morrill entrance. I would estimate that it is about eight feet tall. It has seven stems with leaves extending from the base. The stems and leaves are both green. The base however is a light tannish color with patterns on it that are a deeper brown. These patterns are kind of eyeball shaped and each eyeball shape has a little circle with another circle inside of it. At the end of the stem at the leaf, the stem splits into three veins. The largest vein, the one supporting most of the leaf seems to always point away from the base, while the two other veins support significantly less of the leaf and both point back in the direction of the base. The base has light brown vines coming out of it that run towards the ground. All of these vines come out of one side of the tree. This plant also has two structures growing vertically out of the brown base that do not lead to any leaves. These two vertical structures are also both lighter in color than the green stems that have leaves at the end. The base of the tree does not grow straight up but rather curves, first growing almost parallel to the ground before going vertical. Also, the closer to the top of the base, the darker brown the patterns are. The darker brown parts of the base also have some things growing out them almost like eyelashes. 

Animal Behavior Research Idea

Submitted by ryip on Fri, 03/10/2017 - 10:47

For my Animal Behavior lab we needed to come up with ideas of an experiment we can conduct on animal behavior. I chose to focus my proposal on observing and experimenting on squirrels. I came up the idea with observing the efficiency of squirrels collecting food when there is some sort of inference in the way, like humans or natural obstacles. The experiment would time and test how fast the squirrels would be able to collect the food, and to see if they will be able to learn from past trails or by observing other squirrels performing the same task. 

Photorespiration journal

Submitted by ryip on Fri, 03/10/2017 - 10:46

In my plant physiology class we were discussing the process of photorespiration, which is a process in plant metabolism that take place with CO2 levels are low in plants. I was initially fascinated to learn that a component reaction in photorespiration called oxygenation was considered a very wasteful process it works at a slower rate than other metabolic processes and it requires a much higher metabolic cost. It made me wonder why plants haven’t evolve this process to be more efficient but I realize that this process still essentially does it “job”, just at a much slower rate than ideal. Another interesting component of photorespiration is its usage of an enzyme of RuBisCO. I was shocked to find out that RuBisCO is one of most abundant enzyme in the world because it was an enzyme I had never heard about until we learned about it in lecture.

Introduction Draft

Submitted by ryip on Fri, 03/10/2017 - 10:46

The overall purpose of this Methods project is to prepare a thorough and descriptive manuscript with illustrates the process of research and documentation of a common subject, such as a patch of moss. This project demonstrates the importance of descriptive writing in order for scientific readers and researchers to replicate and perform identical experiments. In order to demonstrate this, a moss plant was required to be located, described and documented. Using visual documentation, such as close-up photos and geographical map images, a multi-panel scientific figure was formed as well. The project then tasked another colleague to replicate the location, description and documentation of the plant, allowing them to create their own multi-panel scientific figure that would allow them to form a similar multi-panel figure. The results indicated that with all replicate experiments there are errors and subtle differences that can affect or change the overall outcome of the initial experiment.

Bacteriocin pp

Submitted by jdantonio on Fri, 03/10/2017 - 10:40

Bacteriocins are peptide chains  that are produced by bacteria that are lethal to other bacterial strains. They are an attractive replacement for traditional antibiotics for many reasons one of which is there potential for coevolution with bacterial strains. As they are produced by bacteria bacteriocins they benefit from the same rapid evolution as the genes for antibiotic resistance. This means they have the potential to counter the evolution of bacterial resistance by evolving themselves to get around the mechanisms of resistance. To compound this bacteriocin resistance in bacteria is rare with only a few known genes having arisen to confer resistance. Bacteriocins also have a very low toxicity, they are even given the GRAS ( generally recognised as safe) status. In addition to this bacteriocins are often narrow spectrum, meaning they affect only a small number of closely related bacterial species. This mean that bacteriocins would lack the digestive side effects associated with traditional antibiotics, as they would not affect the probiotic bacteria of the human microbiome that are associated with digestion. Bacteriocins have also been found to be produced by a number of probiotic bacteria including Fusobacterium mortiferum.It has been demonstrated that these probiotic bacteria of releasing bacteriocins in situ, meaning that they release the bacteriocin while in the intestines of humans and other mammals. Such bacteriocin release in situ has been shown to prevent and treat infection in experiments using mice as a model organism. In conjuncture all these traits give bacteriocins the potential to be the antibiotic of the future and make them one of the most attractive areas of medical study. 

Bacterial Motility

Submitted by amprovost on Fri, 03/10/2017 - 10:36

In my microbiology lab we recently experimented with bacterial motility. 

The expected result of the motility experiment was that the motile organism Proteus mirabilis would have a significant color change as the organism came into contact with tetrazolium salt, and tube containing the non-motile organism Staphylococcus aureus would show very little color change, as the organism would not move and thus not make contact with most of the salt. In the chemotaxis experiment, it was expected that S. aureus inoculated onto the water agar side would not survive, but Serratia marcscens would be able to cross the filter paper bridge from the water agar side and survive on the glycerol-yeast-extract. (GYE), as GYE is nutrient-rich.

            For the experiment with the motility agar, two test tubes were filled with motility agar containing tetrazolium salt and each inoculated with a different bacterial species, one motile (P. mirabilis) and one non-motile (S. aureus). Tetrazolium salt is reduced by bacteria, which results in a change of color from clear to purple. Therefore, a motile bacterium would cause the tube to change more drastically as it would come into contact with more oxidized salt than a non-motile bacteria.

            In the chemotaxis experiment, two bilaterally segmented petri dishes were used, one containing GYE on both sides (the control), and one containing GYE on one side and water agar on the other side (the experimental group). Both of these dishes had 2 bridges made of filter paper crossing the separation, each having one paper inoculated with a motile bacteria and one inoculated with a non-motile bacteria. It was expected that the motile bacteria would be able to move along the paper, and make it to the GYE when inoculated on the water agar side of the bridge. In contrast, it was expected that the non-motile bacteria would not be able to cross the bridge, and would die if inoculated on the water agar.

            In the motility agar, the tube inoculated with Proteus mirabilis showed a significant change in the color of the agar, with much of it becoming purple. The tube inoculated with S. aureus showed almost no color change, with only a slight change to purple around the puncture site of the wooden stick.

            In the chemotaxis experiment, S. aureus was observed to grow successfully when inoculated onto GYE, but showed no movement. P. mirabilis also displayed growth on GYE, and motility in the control plate (the bacteria grew on both sides of the bridge on the GYE). However, in the experimental group, the P. Mirabilis that was inoculated onto water agar did not show chemotaxis, and instead of reaching the GYE it did not grow.

taste receptor transduction

Submitted by jdantonio on Fri, 03/10/2017 - 10:23

Taste is one of our so called 5 basic senses it is the way we determine what foods we can safely eat and get a general sense of their nutritional value. Taste is considered a chemoreceptor type sense as it detects molecules which we interact with directly. There are 5 basic tastes that can be detected by chemoreceptor cells found on our taste buds. Contrary to popular belief there are not exclusive regions of taste on the tongue, all regions can sense all flavors. There are however specialized receptors responsible for the sensing of the five basic tastes. These are salty receptors activated by the presence of Na+, sour receptors activated by the presence of H+, bitter receptors activated by organic poisons(or molecules of similar shape), sweet receptors which respond to carbohydrates, and umami receptors which detect amino acids.

The conversion of the signal from the physical presence of the receptor ligand to membrane potentials that can activate neurons and transmit the sensory information to the brain occurs in two distinct ways depending on the receptor activated. Sour and salty receptors have ion channels which allow there ionized ligand to flow into the cell this depolirzes the cell membrane and eventually cause the opening of voltage gated ion channels in the cell which cause and action potential   at the basolateral membrane of the cell which triggers a synaptic event. The second type of transduction occurs for umami, bitter, and sweet receptors as their ligands are usually uncharged they require and more complex less direct method of transduction. These receptors rely on g proteins which are coupled with the receptor and activate a secondary messenger IP3. IP3 activates ligand gated sodium channels in the cell membrane causing an influx of sodium into the cell. This sodium then stimulates the release of Ca2+ from an inner cellular membrane. The Ca2+ then activates an ATP channel in the membrane. ATP transfer between the receptor and afferent nerve stimulate the neuron and conducts the signal to the brain.

 

Bear MF, Connors BW, Paradiso MA. 2016. Neuroscience: Exploring the Brain. 4th Edition. Philadelphia: Wolters Kluwer. ch. 8 The Chemical senses; p 266-278.  

Lindemann B. 2001. Receptors and transduction in taste. Nature 413: 219-225. <http://www.nature.com/nature/journal/v413/n6852/full/413219a0.html>. Accessed 2017 Mar 10.

Journal #8: Cyanobacteria in Lake Atitlan

Submitted by eriklee on Fri, 03/10/2017 - 03:32

“Without water there is no life,” by Vinny Stanzione, the Scorpion Hunter. At the center of the film, San Pedro a Laguna, Guatemala is a culturally rich town at the intersection of ancient Mayan and modern culture. It consists of the vibrant people, city, and Lake Atitlan. However, the citizens of San Pedro cannot escape the environmental crisis that is coupled with modernization and industrialization. Locals are conscious that Lake Atitlan is becoming increasingly populated, and there is a need to clean up the Lake in order for the people and cities to survive. Residents depend on the water to bathe, clean, and drink. Further, the beauty of the Lake Atitlan attracts tourists and supports the local economy. So it’s clear this areas infrastructure is built on the sustainability and health of Lake Atitlan.

            Mentioned in brief in the video, the central issue with Lake Atitlan’s pollution is the absence of a sewage plant. The previous plant was destroyed in by Hurricane Stan in 2005. Now, the locals spend much of their time cleaning sewage and bacteria from the lake. Yet, Lake Atitlan remains polluted from the local rivers and sewage pipes of the cities. And with the speed of pollution overtaking the speed of cleanup, the sewage and cyanobacteria will only build up and worsen. The most obvious solution is to have the local municipal government rebuild the sewage plant. However, any sort of top-down bureaucracy is guaranteed to be slow and ineffective. Their last mayor of San Pedro, Feliciano, was more concerned with embezzlement than saving Lake Atitlan. Luckily, the current mayor, Mariano, cares more about the people and is capable of rebuilding a sewage plant. Ultimately, it comes down to the citizens expressing enough concern to public officials to make cleaning of the lake a top priority. For now, the city is at the first stage of change, where people are aware of the problem and have begun to take action. It would be even more helpful if the local media and education system informed people about the necessity to clean Lake Atitlan. This seems very possible as the region is concerned with local issues than global issues.

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