Unknown Full Lab Report WORD VRSION

Unknown Full Lab Report WORD VRSION - Lab Report 2 Part 1...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Lab Report 2: Part 1- Unknown Gram-Negative Madison Epting Section 12 October 16, 2016 This report represents my individual effort. I did not receive or offer aid to anyone when performing this assignment, nor did I plagiarize any material. Signed: __________________________________________________________
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Results Textual Summary: Gram-Negative An unknown culture of bacteria was given along with another unknown in two separate slants. The two unknown cultures were mixed together on a slide to gram stain. Fig. 1 shows the appearance of the mixed gram stain. A Gram-positive and Gram-negative stain both appeared on the mixed gram stain. The mixture of both bacterial cultures were placed into threes types of streak plates: PEA, MAC and a blood agar plate. The outcome of the MAC plate, showed in Fig. 3, proved that the Gram-negative was not a lactose fermenter. The blood agar plate shown in Fig. 4 is the plate after 24 hours of incubation; the blood agar plate turned completely brown from its original red color. Since the MAC was selective for Gram-negative, the bacteria from this plate was put onto a slide and Gram stained another time to visualize the pure colony. The appearance of the unknown, Gram-negative pure colony can be seen in Fig. 2. In order to narrow down what the unknown Gram-negative bacteria could be, a series of 4 different biochemical tests were ran based on the morphology of the Gram- negative bacteria; this shape was found to be bacilli. The 4 tests ran for the unknown Gram-negative bacteria was the Indole, H 2 S production, and the MR-VP test. In Fig. 5 , the outcome of the indole test is shown. After incubating the unknown for 24 hours, and adding 12 drops of Kovac’s reagent to the culture, the indole test had a negative result. The H 2 S test in Fig. 6 produced a black color inside the tube; meaning the unknown Gram-negative isolate had a positive result for H 2 S production. The MR-VP test was conducted in separate tubes. One was the Methyl red test (MR) and the other was the Voges-Proskauer test (VP). The MR test concluded that after adding 4 drops of methyl red (shown in Fig. 7) the culture had a red color change immediately
Image of page 2
which is a positive result. In Fig 8, the VP test showed that no color change occurred after the reagents were added, which resulted in a negative test result. Discussion/ Identifying Unknown Gram-Stain The Gram-Staining process provided a way to know which of the two unknown cultures was positive and which was negative. Given that the negative were pink bacilli, this aided in finding a starting point for the unknown bacteria. Streak Plates The blood agar plate used turned completely brown from its original red color. There were divots in the agar which meant the bacteria were consuming the nutrients/agar on the plate. Also, since the blood agar turned such a dark brown, the the colony morphology on the plate was difficult to distinguish. The browning of the plate is described by The Journal of Bacteriology as swarming motility; “It is characterized by differentiation of short, motile, vegetative cells at the
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern