User:Rachel Mary Jones/Notebook/Biology 210 at AU

1/15/2016

Transect 3

Description: This transect is located in the garden area at american university. It contains both abiotic and biotic life. The area has 3 sections of garden with 2 walkways and 3 benches throughout

abiotic life: Trees: 8 tall trees, 7 short trees Bushes: 16 long grassy brown bushes shrubs: 14 short interwoven bushes throughout no rocks

Biotic life -1 birds nest in a tree -1 squirel on the ground

See photo for transect diagram

After observing the transect various samples of nature were collected and used to form a hay infusion, this hay infusion was left to process over the course of a week

1/29/16

Note: all images for this lab are available at https://www.instagram.com/rjbio210/

Instagram: RJBIO210

In this week’s lab, we used the Agar plates to identify and study bacteria.

Hay Infusion observation: The water in the hay infusion is a stagnant murky brown. It has a bit of a musty smell. Sediment has settled around the sides of the infusion as well as at the bottom. I suspect that the smell has worsened due to the growth of the bacteria in the infusion.

Agar plate observations: As I was in a different lab last week, I am catching up on observing the Agar plates. There appears to be bacterial growth on most of the plates (except 10^-7), even with the antibiotics. Two of the plates have dark black growth, however this is due to them being created on blood agar plates. The rest of the Agar plates have yellow and white clusters of bacteria. When the lid of the agar plates are removed, there is a very foul smell coming from the bacteria.

Some different observations: -On the 10^-3 plate, there are spiral colonies and a lot of development -On the 10^-5 plate there are the yellow and white bacteria as on other plates, but there is also what appears to be blue colored bacteria which is unusual.

There are different clusters and colonies of bacteria on the agar plates. The most on the 10^-3 without tet plate. As the dilution gets stronger, we see less and less colonies. We can also see that plates with the antibiotic had significantly fewer colonies, indicting that the antibiotic has an effect. The fact that bacteria still grew all the way up to 10^-5 dilution with tetracycline, indicts this is bacteria that is somewhat resistant to antibiotics.

Determine the mechanisms of action for tetracycline and the types of bacteria that are sensitive to this tetracycline. Cite your sources! Tetracylines are inexpensive antiobiotics often used in humans and animals. It works by going through the cell membrane and attacking the bacteria. Bacteria that have become resistant to tetracyline have often aquired new genes and a coding for a protien which blocks, the Tet from being able to get through the membrane.

Source: Chopra, I., & Roberts, M. (2001). Tetracycline Antibiotics: Mode of Action, Applications, Molecular Biology, and Epidemiology of Bacterial Resistance. Microbiology and Molecular Biology Reviews, 65(2), 232–260. http://doi.org/10.1128/MMBR.65.2.232-260.2001

Wet mount observations (see images) there were smaller clusers of bacteria in the wet mounts. https://www.instagram.com/p/BBaEY-tIoKp/?taken-by=rjbio210 https://www.instagram.com/p/BBaEb0HIoKr/?taken-by=rjbio210

Gram Stain observations: Samples from 10^-3 with tete, 10^-7 , 10^-5 with tet and 10^-7 with tet were created and observed under the microscope. All of these slides showed different types of bacteria growth. In the 10^-3 plate at 40x it looked like muscle tissue but when enhanced, there were small clusters of tightly grouped bacterial colonies. In the 10^-7 without tet, there was a flowing river of bacteria in the middle of the plate. (see images)