Bacterial Lawns

As predicted the E. coli colony transformed with either the PUC18 or the lux plasmid developed an ampicillin resistance. Which made it easier for them to not only survive but also replicate in both the LB agar plates and the LB ampicillin rich agar plate. However the E. coli colony not treated with the plasmids could not survive and colonize in the LB ampicillin rich agar plates. The plate that had no ampicillin in its environment and no plasmid treated E. coli served as a positive control for this experiment because it demonstrated how the E. coli would colonize and grow in a normal setting. The cells in the positive control plate grew into lawn colonies because they were not placed into a selective environment or transformed, so they had no need to acquire ampicillin resistance. Two plates in the experiment contained E. coli cells that were transformed with either the PUC18 or the lux plasmid but were placed in an ampicillin free environment. These two colonies grew

The Gram stain was used to determine if the bacteria was gram positive or negative. A negative test shows a pink color and a positive test is a purple color. When a bacterium is negative it is because it has an outer membrane and a thin layer of peptidoglycan that is much harder to stain. A positive bacterium has a thick layer of peptidoglycan and no outer membrane that can be penetrated by crystal violet.

The next step of the project included preparing a Gram stain to discover the cell shape, arrangement, and if the bacteria is gram positive or

In the LB (pGLO negative), it is expected to not see any colonies growing. As a result of this experiment, it shown any growth colonies but this only had shown a large number of white, circular colonies that were found across the surface of the agar. In the LB/Amp (pGLO negative), it is expected to see any growth colonies. In the experiment, the resulted was no growth colonies because this has Ampicillin and no pGLO. Now, the LB/Amp (pGLO positive), it is expected to have growth colonies in the agar plate. As a result, it was shown growth colonies in the agar plate because has positive pGLO regardless having Ampicillin. In the other hand, both positive pGLO have the same components but in one plate was added Arabinose. The LB/Amp/Ara (pGLO

Next I performed a KOH test to further confirm that my organism was a Gram-negative species. For the KOH test, I added 3 drops of 10% potassium hydroxide (KOH) to a small drop of distilled water onto a clean microscope slide, transferred a visible clump of organism to the KOH solution using my inoculating loop. I than mixed the cells into the solution using small, circular motions for 60 seconds and then lifted up the loop to look for what appears to be a “stringing” affect which means it’s confirmed that it is gram- negative species. Next, I created a streak plate using nutrient agar so that I could see pure culture of my organism. I aseptically obtained a loop full of my organism and gently inoculated one quarter of the nutrient agar plate by running the loop back and forth across the surface. I then flame sterilized the inoculating loop, allowing it to cool for 10 seconds, and then streaked the organism from quadrant I into quadrant II using a zigzag motion technique. I repeated those steps streaking from quadrant II to quadrant III and then streaking from quadrant III to quadrant IV. Once completed, I put the streak plate in the incubator at 37° for 24-48 hours. 48 hours later, I check my streak plate and it had a lot of growth on it. I was able to determine that the organism was definitely an off white color, opaque. The IV quadrant was the quadrant that best

This experiment was conducted to find the genus and species of an unknown bacteria prescribed by the lab teacher, which was unknown bacteria GA3 in my case. Identification of unknown bacteria techniques are used on an every day basis to figure out what type of bacteria it is and to find the best method of how to treat a patient with this bacteria (1). All five “I’s” of Microbiology were used in the testing for the unknown culture. Inoculation was used several times to put the unknown culture into agar plates or into biochemical test tubes. After Inoculation of these tubes or plates, they always were placed into the incubator for further growth and development. Isolation was used to make sure we got the correct bacteria we were testing for. After each further isolation, we gram stained the culture and inspected the culture under a microscope to further help in the identification process of the unknown bacteria. Multiple tests were done on the unknown culture to make sure we were confident in what kind of bacteria the unknown was.

This experiment was given to us to utilized previous knowledge learned throughout the semester to identify a gram negative unknown bacterium. We had to first learn the difference between a gram negative and a gram positive organism. We started off with doing gram stains to determine whether it was positive or negative. Based on the gram stains, a gram positive stains purple and a gram negative stains pink. A gram positive stains purple because the cell walls is made of a thick peptidoglycan layer and doesn’t

20. The -DNA/LB/AMP plate had many transformed colonies of bacteria and they appeared white. The 2nd plate listed had the same except it looked white and exposed to room light and green with a UV light.

The aim of this investigation was to find out which antiseptics were most effective at preventing the growth of bacteria.

In the world of microbiology it is vitally important to be able to discern the identities of microorganisms. Not only is it important in a lab setting but as well as in healthcare in general. Properly identify what strain of bacteria a person has will aid in the proper medicine and dose given. Throughout the semester we have learned about different types of bacteria and certain test that can clearly identify them. The purpose of this lab report is to identify a Gram-positive or Gram-negative bacterium. Using all the knowledge of procedures and lab techniques identify the unknown and discuss all the tests you performed.

The objective of this experiment was to identify two unknown bacteria from a mixed culture. Which was done by using the aseptic technique which was very important to avoid any contamination and keeping the workspace clean while culturing bacteria for different tests. To start, I chose a tube which had a solution of mixed culture. I used the flame to sterilize the inoculating loop and dipped it into the tube and streaked for isolation on 2 TSA plates and placed them in an incubator at 37 for 24 hours. Next day I observed the growth of 2 different types of colonies one for each unknown on the two plates. So I picked the best one and labeled it as master plate and discarded the other plate. From the master plate, I subcultured each type of colony

For this experiment, I utilized unknown number three which I later identified as Staphylococcus epidermis. I concluded that the unknown organism was Staphylococcus epidermis based on numerous tests performed in the laboratory which I will discuss in detail throughout this paper. One of the first tests performed was the Gram Stain. The Gram Stain

Flow Diagram Homework Assignment Name: Preetam Ganti Using the table below, explain the purpose of each of the steps of the Experimental Flow Diagram (Figure 1 from your lab manual – it is provided on the next page) for answering the two research questions guiding this laboratory investigation: 1. Is the bacterial contamination at these three farms due to the same plasmid or different plasmids? 2. What is the frequency of tetracycline resistant bacteria in the beef farm cultures?

I knew what the results meant and what test I needed to do next, but when I went to get my new media I asked for the wrong one and did not realize it until I was back at my table. This time I performed a lawn technique instead of a streak isolation using aseptic technique. I didn’t use a swab this time I used an inoculating loop to perform the test and the bacteria came from the T-soy plate inoculated on the first day. This test was performed using aseptic and proper disposal techniques. The plate was placed inverted in the incubation rack.

a. LB+plasmid and LB-plasmid: Both of these plates had a lawn of bacteria. This proves