User:Sarah Connolly/Notebook/Biology 210 at AU
Lab 5: February 13, 2014
Identifying Algae and Protists
Lab Objective:
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Methods & Procedure:
Data:
Conclusions and Future Plans:
Lab 4: February 6, 2014
Plants and Fungi
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Lab 3: January 30, 2014
Microbiology and Identifying Bacteria with DNA
Lab Objective: The purpose of this lab will be to observe the bacteria cultures we prepared in lab 2. This will allow for identification of bacteria and/or fungi that was initially present in our hay infusion and transect. We will utilize both agar plates and agar plates with the antibiotic tetrocycline present. We will select several colonies to characterize using cell morphology, gram staining, and a wet mount. Once we have recorded the results, we will select DNA from our selected bacteria colonies and prepared for PCR testing next week.
Hypothesis/Prediction: There will be a variety of bacteria present in the hay infusion, and several types will overlap across different plates and dilations.
Methods & Procedure: We began the lab by counting the total number of bacteria colonies on each plate. We then multiplied these numbers by the conversion factor warranted by the dilution present on that particular plate. We then compared the number and types of colonies that were on plates with the antibiotic present against the plates that simply had nutrients. This included noting diverging and similar morphology and recording it. After these more general observations, we made a selection of two bacteria colonies from the nutrient agar plates and two bacteria colonies from the tetracycline plates. We made wet mounts and then observed motility, as well as the presence of cilia or flagella that would make i possible. We also viewed our selections under a microscope and recorded more detailed cell morphology to compare within the specimens. The last step in characterizing these slides was by gram staining them. o to this, we used heat from the Bunsen burner to fix the bacteria, and performed several rounds of washing and rinsing the sample with chemicals. Two of these were dyes, one of which adheres to gram positive bacteria because of the presence of the cell wall, and the other to the second layer of cell membrane (gram negative). Iodine and ionized water were also used as washes to get rid of excess dye on the plate. The final step was preparing to run PCR next lab by isolating some of the bacteria's DNA. using the centrifuge.
Data: Tables will be added once I have them on my computer and thus able to upload.
Conclusions and Future Plans:
SC
Lab 2: January 30, 2014
Identifying Algae and Protists
Lab Objective: The main objective of this lab is to observe and identify algae and protists that have grown in the hay infusion we collected over the last week. The main objective of this lab is to be able to able to identify our specimens based upon our understanding of the characteristics of protists and algae and to use the provided dichotomous key. We will also begin preparation for next week's lab.
Hypothesis/Prediction: There will be a presence of algae and protists in the culture, based upon the location of initial transect and where we took our initial sample.
Methods & Procedure: This lab began with the observation of common algae and protists under the microscope. We began with brown algae, and green algae, and then saw a variety of protists. Based upon the usage of the dichotomous key with these known samples, we moved on to the main objective of the lab: identifying those from our transect. We collected three samples, electing to use the top, middle, and bottom niches of the hay infusions. These were the most clear divisions, with the settling serving as distinct separation from the heavy dirt at the bottom, milky tones in the middle and film on the top. We created a wet mount for each niche and observed them under the microscope.
We then prepared for the next lab by creating serial dilutions from way had grown in our hay infusion. This was completed by beginning with a heavily concentration volume of the sample, and gradually diluting it through movements of small volume to another container, mixing, and moving another small sample to the next container. We then prepared agar plates using each dilution. 4 dilutions were prepared as controls, while 3 served as test plates with tetracycline present. The math needed to complete this will be uploaded.
Data:
Hay Infusion Observations: Our infusion is extremely smelly, which may be accountable to the presence of rotting leaves. The bottom niche is a deep green-brown, where a layer of dirt has settled. This color gradually lightens to a very cloudy grey as you move up the different niches. The small sticks and leaves that we collected tend to be in the middle and top of the infusion. The top niche consists of a film, that can perhaps be linked to the milk powder we added as a nutrient. Pictures will be uploaded.
Protists and Algae Observations: As noted earlier, we elected to take samples from the top, middle and bottom niches. On the top level, we identified our largest sample of Gonium (~80 micrometers). The sample had between 15 and 18 cells in the colony, with green and brown extending arms. The top layer also yielded Volvox (~400 micrometers). This was more complex than the Gonium but shared the color and arm traits previously observed. On the middle level, we observed a smaller Gonium (~60 micrometers). This could have been attributed to less direct sunlight presence or nutrients available. The second organism observed in the middle was a chilomonas protist (~20 micrometers). This protist had a more oval, or elongated shape, with a difficult to observe flagella, and was a clear color. On the bottom of the hay infusion, we identified a paramecium (~5 micrometers). It was immobile with a reddish tint to it, yet what still mostly clear. The bottom layer also yielded what appeared to be a Goniu, but we were not quite sure because of its small size (16 cells). It was green brown like our other Gonium samples and had an oval shape.
Conclusions and Future Plans: It was interesting to observe the variety of organisms in the hay infusion. Based upon my past class in infectious diseases, the next lab will be even more enlightening in terms of the response to the tetrocycline at the different dilution levels. SC
Lab 1: January 23, 2014
Initial Transect Activity
Lab Objective: The objective of this lab was to examine a transect on the grounds of American University, to gather a baseline for further observation later in the semester. During this excursion, a collection of material at the site will be collected to grow a hay infusion to serve as a source for later laboratory experimentation.
Hypothesis/Prediction: Based upon our assignment to the 'pine trees' area, I predict that the moist leaves in the transect will provide a medium to grow a variety of bacteria growth in the future.
Methods & Procedure: For this experiment, we simply observed our assigned location on campus. Once we had arrived from our trek down Massachusetts Avenue, Kaitie and I took notes and photographs of the immediate area. We identified a variety of trees in the niche, as well as a variety of low-growing vegetation. We selected an area in the center of our sector about two feet in front of the largest tree to gather our sample, in which we included ivy leaves, pine needles, soil and rotting leaves from about two inches underneath the top level.
Data:
Location: Tree area near the seminary
Topography: On a steep hill, with thick ground vegetation. Located in proximity to a brick building in the seminary. This is high potential of human impact at the site because of its proximity to Massachusetts Avenue and a public picnic area. In warmer weather, this area would be frequently visited by members of the seminary and community at large.
Abiotic components: Breeze slightly blocked by hill. Building outside of the marked area impacts the wind and water available to the root systems of the trees. There was some discarded wrapped strewn within the leaves.
Biotic components: Thick ivy on the ground, soil, pebbles, rotting leaves from surrounding trees. One pine tree, one sycamore tree and one holly tree. All were quite old due to the thickness of their stumps, though the holly was thinnest. There was a small stump, recently cut, behind the large sycamore tree that demonstrated the impact that human interaction has had on this area (beyond growing it). Full canopies on the holly and pine trees, while the birch was missing several branches and had no leaves. There were squirrels and birds in the branches, and evidence of deer based upon droppings that Laina pointed out.
Our sample was collected from a location upon my diagram of the site.
Photos and that layout will be added at a later date.
Conclusions and Future Plans: Our transect will be interesting to observe as the weather transitions to the spring because of its proximity to many other living organisms. Our hay infusion has the potential to yield some very interesting results based upon the variety of vegetation present in the transect. SC
