 and images/drawings if you have them. Ensure to address all red text from protocol. For more instructions see TA notebook. SK
Objectives 1. To understand how to use a dichotomous key 2. To understand the characteristics of Algae and Protists
This lab will address the first objective through identifying different organisms on a wet mount and characterizing them from eight known organisms. The second objective will be addressed through observing our Hay Culture Infusions from the previous week by taking samples from the culture and identifying the various organisms in the sample.
Dichotomous Key 1. Make a wet mount of a sample and observe at 4x objective and then at 10x 2. Characterize the organism found in the sample, measure the organism 3. Match description with organisms from a Key
Hay Infusion Culture Observation 1. Observe smell, appearance of the culture 2. Take a few samples from two different niches, including plant matter 3. Make a wet mount with samples to observe 4. Characterize at least three different organisms in each sample 5. Measure organisms
Preparing and Plating Serial Dilutions 1. Pour 10 ml of distilled water into four tubes, labeled 2,4,6,8 2. Label four agar plates and three tetracycline plates, labeled 10^-3,-5,-7,-9 3. Mix Hay Infusion Culture and take 100 µl sample and add to first test tube 2 4. Take 100 µl from test tube 2 and pipette into test tube 4, etc. 5. Take 100 µl from 10^-2 test tube and pour onto agar plate 10^-3, spread sample. 6. Repeat for tetracycline plate
Sample from Procedure 1 was identified as paramecium. Had a long oval-shaped cell structure and smaller organisms inside.
Hay Infusion Culture Observations- Smells like moss, sour; cloudy appearance; some matter settled to the bottom; floating layer at the top (greenish, brown color); apparent reduction in mixture from the starting point.
Two niches for wet mount- Top layer, bottom layer
Organisms in top layer appear to be paramecium, might be chilomonas or some other outside organism? Looks like a large colony of cells with flagella. Paramecium are protists that have cilia for movement; have two nuclei; reproduce asexually and sexually. Organisms in bottom layer appear to be chlamydomonas cells. Small, round cells with one or two long flagella.
We were unable to identify more than one clear organism in our sample. There is a potential that one of the organisms might be bacteria of some sort.
If the Hay Infusion had been observed for another two months, we might have seen a significant growth in organisms in the sample. The composition of our samples was affected by selective pressures such as: winter conditions, animals such as squirrels.
Conclusions The structures and characteristics of various algae and protists were observed in the first part of the lab. We were able to identify multiple paramecium cells. Our Hay Infusion Culture was observed to be clearer in color than the previous week, with more settled matter. Samples were taken from two different niches (top and bottom layer) and paramecium were identified in the sample. For next week, we created serial dilutions from the Hay Infusion Culture and treated four nutrient agar plates with dilutions and four agar + tetracycline plates with the dilutions as well. For future studies, it might be helpful to have other Hay Infusion Cultures available in the case that organisms are unable to be identified.
Objectives 1. To understand the characteristics of bacteria 2. To observe antibiotic resistance 3. To understand how DNA sequences are used to identify species
The first objective will be addressed through observing the nutrient agar and agar + tetracycline plates that were made in the previous lab, and counting the colonies formed on the plates. The second objective will be addressed through observing and comparing the agar + tetracycline plates to the nutrient agar plates; tetracycline plates with growth indicate antibiotic resistance. The third objective will be addressed through PCR of antibiotic resistant bacteria and nutrient agar bacteria to amplify the rRNA gene to ob