9: Creosote Bacteria Identification Continued

Continued:Creosote Bacteria Identification for "PC Sample" and "White Tank Mountain Samples"

This week I continued to perform two more tests on the creosote sample that was taken on the Phoenix College campus. The first test I performed was  Mannitol Salt Agar (MSA) which is used to identify if a bacteria can tolerate a high saline concentration. The second test performed this week was called  MacConkey Agar (MAC) which is selective for gram-negative bacteria. The inoculated plates were placed in the incubator at 37 degrees Celsius and results will be recorded by the end of the school week.
Additionally, the creosote plate samples from the White Tank Mountain area were continued to be further isolated with the goal of obtaining pure culture samples.

8: Larrea Tridentata (Creosote) Research Proposal

Retrieved from: Sonora-desert-detective

Leaf Microbiome of Larrea tridentata Grown in Urban Phoenix Versus 
Grown in Rural Phoenix

Background Information

Larrea tridentata is a species of plant common to the Mojave, Sonoran, and Chihuahan deserts. Larrea Tridentata’s unique properties allow for its shrubs not only to grow deep roots but spread out across more surface area in the which allows the shrub to dominate absorption of nutrients in the soil. Due to the chemical durability of the Larrea Tridentata species, many other organisms have adopted the Larrea Tridentata as their host environment (Schultz 1999). However, research has shown rising levels of CO2 can alter the chemical composition of leaves in Larrea tridentata. Additionally,the nutrients in the soil can be altered. (Wang 2011). Research has also indicated that environmental conditions and changes can influence adaptive traits of plant function over time (Kimball et. al 2012). It is imperative to learn more about the differences in the leaf microbiome of Larrea tridentata in urban and rural areas to gain understanding of how increasing urbanization can impact microbiome development and sustainability over time.

Research question

Is there a difference in the leaf microbiome of the Larrea tridentata species in the Phoenix urban area and surrounding desert rural area?

Hypotheses

Hypothesis 1:

The leaf microbiome of Larrea tridentata found in the urban Phoenix area is detectably different than the leaf microbiome of Larrea tridentata found in the Phoenix rural areas.

Hypothesis 2:

As a result of urban area heat islands and a greater concentration of CO2 emitting vehicles, it is hypothesized that elevated CO2 and pollution will result in different microbial communities of Larrea tridentata growing in urban areas.

7: Creosote Bacteria Identification from White Tank Mountain Area

Creosote Bacteria Identification from White Tank Mountain Area

This week was focused on completing more bacteria-identification tests on the leaf sample collected from a creosote bush here on Phoenix College's campus. The second focus of this week was to isolate bacteria samples taken from two creosote bushes located in the White Tank Mountain Area (Sample Extraction Coordinates:33⁰ 34’ 31’’ N, 112⁰ 34’ 44’’ W.

The samples obtained included taking swabs from a creosote bush's leaves and streaking them onto three TSA plates (Sample ID Label = Plate 1 C1-C7; Plate 2 C1-C6; and Plate 3 C1-C8). From an additional creosote bush, three vials of leaf samples were collected and are in the process of being streaked on TSA plates. 
Plates 1-3 were taken and observed for different colony types. Next isolation streaks on TSA were performed for each colony type observed. A total of 21 colonies were observed and streaked on TSA. After being incubated at 37 degrees Celsius, the TSA plate samples were observed for colony growth, and it was determined that the TSA plate samples for the 21 colonies should be further isolated with the goal of obtaining pure cultures. Currently, the second round of isolating the colonies is in process. Below are pictures of the three plate samples collected from the one of the creosote bushes in the White Tank Mountain area. 
     

6: Cold Case of the Flu

Cold Case of the Flu
This past week, the identification of the unknown bacteria found on the Creosote sample 1 "PC Sample" was put on hold because I came down with the Flu. Three reasons why I would have rather contracted some other virus or sprained a body part in lieu of getting the Flu:
1. Vomit makes me cry (there was a lot of vomit associated with my Flu).
2. I had the worst headache of my life, I thought I was going to die.
3. It took me like nine days to start to feel better.
It's been nine days since I came down with the flu, I still feel nauseous and have an upset stomach. Nonetheless, I am glad to be back at school and working on my S-Stem project.

5: Creosote Bacteria Identification Continued

                                                                  

Gelatin Test (Pre-incubation)

Creosote Bacteria Identification Continued
This week was focused on completing a serious of tests to gather information which will aid in the identification of the unknown bacteria sample collected from a creosote bush here on Phoenix College's campus. The test performed this week: Simmon's Citrate, Growth at 42 degrees Celsius, TSI, Gelatin, FTM, Glucose Fermentation, and Triptone.  The tests completed were the Glucose Fermentation Test and the Growth at 42 degrees Celsius. The unknown sample was negative for glucose fermentation and positive for growth at 42 degrees Celsius. I have created an excel spreadsheet to keep track of tests that were completed and their results (See table below). 

4: Adventure of the Creosote

Positive gram stain and Cocci dipole cell morphology

Adventure of the Creosote (Larrea tridentata)
Fun fact: In Mexican culture, the Creosote is known as "The Governess."Another fun fact: The Creosote is not the most visually appealing plant to look at, but it is partially responsible for contributing to that wonderful "desert rain smell."
For the remainder of the semester, I will be working on a project that focuses on learning about the various types of bacteria present on Creosote bushes (Larrea tridentata) in urban and non-urban environments; convenience sampling was used as a result of limited access to creosote bushes. After a leaf sample was collected from a Creosote bush on the Phoenix College campus, the process of identifying microbes had begun. First, the leaf sample was mixed with Peptone water and vortexed for 20 seconds. After, I used the aseptic technique to inoculate a TSA plate with an isolation streak. Next, the TSA sample incubated for approximately twenty hours. Individual off-white, punctiform colonies were present and a Gram Stain test was performed; the bacteria tested positive for the gram stain and consisted of a cocci dipole cell morphology. The Catalase test was also positive for the catalase enzyme. After, a Glucose Fermentation test was also performed on the sample and is currently in the incubator.  Next steps for the sample are recording the results for the Glucose Fermentation test and following the next tests outlined in the identification guide.

3: Endospore Stain, Glucose Fermentation, and MSA Tests of Unknown Bacteria

Endospore Stain, Glucose Fermentation, and MSA Tests of Unknown Bacteria
Throughout my experimental process of identifying an unknown bacteria, I have so far observed that my unknown bacteria has a positive cell wall and bacillus cell morphology. To further test my unknown bacteria in hopes of identifying the Genus species, I performed an Endospore Stain, followed by a Glucose Fermentation test when the unknown bacteria tested positive for endospores. After the Glucose Fermentation test revealed that the unknown bacteria had a pH level< 7, I performed a MSA (Mannitol Salt Agar) test. The MSA test was positive. Using the Identification Flow Chart, I was able to identify the unknown bacteria as Bacillus subtilis. See below for Experimental Procedures and Results.






Smear Preparation and Endospore Stain Method Procedure:
1. Prepared two slides by drawing a nickel-sized circle on each slide and labeled slides “1” and
“2”.
2. Used micropipette to place one drop of water within each circle of the slides.
3. Placed inoculating loop in bacti-cinerator for 5 seconds (used stopwatch to keep time).
4. After, used the sterilized inoculating loop and aseptic technique to obtain a sample of the
    unknown bacteria and smeared it into the water droplets of each slide.
5. Let bacteria smear dry on each slide.
6. After each bacteria smear dried, they were heat-fixed for 5 seconds each (used stopwatch to
    keep time).
7. Brought beaker full of water to a boil using hot plate.
8. Placed slide 1 over beaker of boiling water using rack tool and covered the slide with a
    paper towel.
9. Soaked the paper towel in Malachite Green solution and timed it for five minutes using
    stopwatch. Added more Malachite Green solution as needed when paper towel dried.
10. After five minutes, rinsed slide for 40seconds with water.
11. Added Safranin Stain and timed it for 75 seconds. Blotted dry with bibulous paper.
12. Repeated steps 8-11 for slide 2.
13. Prepared both slides for oil immersion under microscope.
14. Placed coverslip on slides and focus objective to 40x lens.
15. Rotated 40x lens halfway to 100x lens and placed one drop of immersion oil on each slide.
16. Viewed slides 1 and 2 through 10x and 40x lens.
17. Unknown bacteria was positive for endospores.
Experiment errors:
Initially placed wrong coverslip on slides.
Timing for second slide was 30 seconds instead of 40.
Could not focus to 100x lens.
Glucose Test Fermentation Procedure:
1. Used Aseptic Technique and took inoculation loop and retrieved sample of unknown bacteria.
2. With the inoculating tool, placed sample of unknown bacteria in test tube.
3. Incubated test tube at 37°C for approximately 16 hours.
Results: The Glucose Fermentation test revealed a yellow liquid color indicating a positive result for a pH <7.
MSA Test Procedure:
1. Used Aseptic Technique and took inoculation loop and performed isolation streak of the microbe onto the surface of the MSA plate.
4. Incubated MSA plate at 37°C.
5. Left inoculated MSA plate in incubator for approximately 16 hours.
Results: The isolation streak revealed a yellow color indicating a positive result