Pglo Lab Report

The pGLO plasmid is engineered to express green fluorescent protein (GFP) in the presence of the sugar arabinose as well as the ampicillin resistance gene β-lactamase (bla) (Brown, 2011). Original E. coli HB101 do not have ampicillin resistance or the GFP gene allowing them to glow under UV light. In this experiment, we transformed E. coli HB101 with the pGLO plasmid by heat shock to make the bacterial cells competent, allowing the plasmid to enter the cell (Brown, 2011). The mixture of bacteria with pGLO plasmid were given recovery time after heat shock, then spread on LB/amp and LB/amp/ara agar plates. The bacteria mixture with no plasmid added were spread on LB and LB/amp agar plates and all four plates were incubated at 37°C for

The purpose of the PGLO lab was to be able to perform a procedure known as a genetic transformation. We used a procedure to transform bacteria with the gene that codes for a Green Fluorescent Protein (GFP). The actual source of the GFP gene that we used in this complicated experiment is the bioluminescent jellyfish Aequorea victoria. This protein causes the jellyfish to glow under a UV light that was provided in the dark. After the transformation procedure, the bacteria showed their newly acquired gene from a jellyfish and produced the fluorescent protein, which as a result, causes it to glow. If the bacteria glowed in the dark, that was the initial sign that the experiment was successful.

This experiment was designed to test and observe the transformation efficacy of the pUC18 and lux plasmids in making E. coli resistant to ampicillin. Both plasmids code for ampicillin resistance, however, the lux plasmid codes for a bioluminescence gene that is expressed if properly introduced into the bacteria’s genome. The E. coli cultures were mixed with a calcium chloride solution and then heat shocked, allowing the plasmids to enter the bacteria and assimilate into the bacterial DNA. The plasmids and the bacteria were then mixed in different test tubes and then evenly spread onto petri dishes using a bacterial spreader, heating the spreader between each sample to make sure there is no cross contamination. Each of the dishes was labeled and then incubated for a period of 24 hours. The results were rather odd because every single one of the samples grew. Several errors could have occurred here, cross contamination or possibly an error in preparation as every single sample in the class grew, meaning all samples of the bacteria transformed and became ampicillin resistant.

The experimental part of the lab consists of setting up the materials needed. A sample of E.coli and a solution of calcium chloride are first obtained and placed in different test tubes. 630µL of Calcium Chloride (CaCl2) are then removed from the test tube and inserted into the test tube containing E.coli cells (Alberte et al., 2012). The newly formed substance of Calcium Chloride and E.coli is then mixed and incubated in ice for 10 minutes, making the cells more competent. Two test tubes are obtained and labeled; the first test tube is labeled with pUC18 and the second one with “Lux” to represent the plasmids being used. These two test tubes are then incubated in ice. 3µl of the set plasmid are added to each of the two test tubes. The test tubes are tapped to guarantee the cells are well

In the pGLO Bacterial Transformation lab, Escherichia coli is transformed with a gene encoding green fluorescent protein by inserting a plasmid containing the GFP gene, beta-lactamase, and arabinose into the bacterium. Successfully transformed bacteria will grow in the presence of ampicillin and glow a bright green color under ultraviolet light. The sugar arabinose is responsible for switching on the GFP gene in the transformed cells, without it, the gene will not be expressed.

Spin the two tubes in a centrifuge for 5 minutes on opposite side of the centrifuge. The bacterium will collect at the bottom of the tube, so pour out the extraneous supinate. Then, add 250 microliters of buffer. The Ca2+ cation of the buffer neutralizes the repulsive negative charges of the phosphate backbone of the DNA and the phospholipids of the cell membrane allowing the DNA to pass through the cell wall and enter the cells. Place both tubes on ice. Then add 10 microliters of water into one tube and 10 microliters of plasmid DNA into another tube labeling the one with DNA with a + and the one with water -, and place on ice for 10 minutes.

The pGLO plasmid will transform the E. coli bacteria with a gene called GFP that codes for the Green Fluorescent Protein in the genetic code. GFP was discovered in the jellyfish, Aequorea victoria as a green fluorescent light emitted from the jellyfish. It was typically seen in the dark upon its activation and since then has been used in studies relating to genetic transformation. (Chalfie and Tu 1994) The majority of the studies test the many different factors that are required in the transformation of pGLO which will determine the functionality of GFP in the E.coli bacterium. The first experiment in transforming GFP and E. coli was completed in 1994 by Chalfie and was further refined the same year. The experiment proved the importance of using restriction enzymes, and DNA ligase in the process of transforming GFP to identify arabinose as the primary activator, and to identify the ampicillin

The petri plate with the +pGLO LB/amp/ara will allow for the E. coli who have accepted the plasmid to glow and express the GFP. The E. coli will only express GFP if they are exposed to the arabinose sugar, and the bacteria also have to be exposed to the pGLO. Also the bacteria that are exposed to the ampicillin, but are not exposed to the pGLO will perish. Other plates may grow, but not express the protein.

In our hypothesis we stated that only the container containing all of the components +pGLO, LB broth, ampicillin, and arabinose would be the one that genetically transformed. In order for the bacteria to grow at a rapid pace all it needed was LB broth but when you added ampicillin, an antibiotic, it killed off all of the bacteria. +pGLO has the gene to resist the antibiotic so when that was added it was allowed to grow but there was no sugar to turn on the glowing protein. Finally, after arabinose, a sugar, was added it turned on the switch located in the +pGLO for the fluorescence and enabled to grow and glow.

Genetic transformation occurs when genes are inserted into another gene to change the organism’s trait (Weedman2016). In this experiment, we proceeded to transform the E. coli bacteria with a gene that contained green fluorescent protein. The green fluorescent protein is used in experiments because it beams a green color under a UV light (Chalfie2008). Typically, it is used to mark the expression of genes, which is why it serves as the symbol for all gene expressions (Tsien1998). In the experiment, we will be using pGLO as the organisms that will transmit the disease, otherwise known as a vector. The pGLO in the experiment

As expected the higher growth was seen in the E.coli cells growing outside ampicillin environments, this is because they grow freely with only minor risk, such as contamination. Possible errors in the experiment can have included the difference in the amount of liquid broth added to the E.coli sample that contained no plasmid and that which contained a plasmid. The sample containing no plasmid received half the amount of liquid broth (150µl) as that of the other two samples (300µl). Liquid broth can have incremented the growth in the plates containing plasmid twice as much as on the rest of the plates. Another artifact which can have affected the results was the time each solution spent in both the ice and hot water bath. Uneven sharing may have also taken place within the E.coli used for each plasmid leading to different amounts of colonial growth in the different agar plates used. More accurate results would have been possible if there had been more variation in both E.coli and plasmid

The objective of this experiment was to genetically transform E.coli cells to express ampicillin resistance and to produce the green fluorescent protein by using the pGLO plasmid. It was hypothesized that only the cells with pGLO DNA added to the solution would be able to survive in the same environment as the ampicillin, and that only the cells grown in the plate with arabinose would fluoresce bright green. The results supported the hypothesis, showing that the +pGLO LB/amp/ara plate was the only plate that had fluorescent cells and grew. Additionally, that +pGLO cells were the only ones that grew on an LB/amp plate.

In two weeks of genetic transformation, we were able to successfully complete the objectives of the lab by correctly performing a transformation of bacterial cells. During the lab, we were able to successfully complete the components that were necessary for a transformation of bacterial cells. Viable cells were transformed, able to grow, and were put in a sterile environment conducive to growth. With the exception of the plate labeled LB/Amp: -pGLO, our results followed the lines of a successful experiment. The LB/Amp: -pGLO plate was contaminated and had colony growth in it. In order for the transformation to be completely successful the LB/Amp: -pGLO plate would have had zero colony growth. As stated in the laboratory manual, biotechnologists

Transformation was discovered by Frederick Griffith in 1928 in his classic experiment on Streptococcus pneumoniae. Unknown to him, his “transforming factor” which changed the non-pathogenic strains into pathogens was DNA. This was discovered in 1944 by Avery, MacLeod, and McCarty who, using isolated DNA from S. pneumoniae, were able to again cause virulence in a previously harmless strain.

This experiment was performed to test the hypothesis if LB nutrient broth, +pGLO and -pGLO Ampicillin, and Arabinose was placed in the E. coli plates, then there will be a significant growth in the newly transformed bacteria and it will possess the ability to glow under UV light. The measurements were recorded from the bent glass tube in each glass test tube. The transformation protocol tested for the newly possessed traits in E.coli bacteria. Throughout the experiment there were many probable reasons for failure. If the pipettes and sterile loop were not thrown out in between each use, a cross contamination could cause a miscalculation in the experiment causing the data results to fail. The hypothesis that was tested was validated due to the positive results with each experiment stating that newly transformed organisms due in fact pass on traits.