Michael Fedorovsky
4/6/16
BI108 Lab D8
Escherichia coli transformation for ampicillin resistance and GFP expression using pGLO plasmid and calcium chloride transformation solution
Abstract
Within the growing field of biotechnology, genetic engineering is becoming more important than ever. To illustrate an application of genetic transformation, pGLO plasmid containing the reporter gene GFP, an arabinose operon, and a gene coding for ampicillin resistance was used to genetically transform Escherichia coli. Plates of LB/amp and LB/amp/ara containing this plasmid and controls of LB and LB/amp not containing it were set up for visual observation of transformation as well as transformation efficiency calculation. Results exemplified that transformation occurs in the LB/amp/ara plate with an efficiency of 3000 transformants per microgram of DNA. Results also show that the transformed DNA became ampicillin resistant, while the untransformed DNA was not ampicillin resistant. The results of this experiment and further experiments like this one can be used to effectively advance the use of genetic transformation in the medical and environmental fields as well as developing additional uses for GFP as a reporter and pGLO as a plasmid.
Introduction
Genetic transformation is the expression of foreign genetic material resulting in the alteration of a normal genome by the exogenous DNA. This technique was first introduced in 1944 by Avery, MacLeod, and McCarty who dealt with
In order to find transformation efficiency, the total number of colonies on the plate is divided by the total amount (µg) of DNA spread on the plate. All the factors that must be taken into account while finding the transformation efficiency include; the total amount (µg) of plasmid DNA used, the total volume (µl) of cell suspension prepared, the fraction of DNA spread on the plate and finally the total amount (µg) of DNA present on the plate. In the LB/AMPC plate the transformation efficiency was 8.2 x 103 colonies per µg of plasmid DNA while the LB/AMPlux plate the transformation efficiency was 1.07 x 104 colonies per µg of plasmid DNA. The transformation efficiency for the LBC and LBlux plates were not taken into account, even though they too transformed because they were not in a restrictive environment where they needed to express their ampicillin resistance genes in order to
E. coli HB101 was transformed with pGLO plasmid then grown on media containing ampicillin and/or arabinose and on medium containing neither (Brown, 2011). This is done for selection of transformed cells since not all cells are expected to take up the plasmid (Brown, 2011). We also expect roughly the same CFU on any plate(s) receiving samples from the same microcentrifuge tube, since they are getting the exact same
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 plasmid pGLO contains an antibiotic-resistance gene, ampR, and the GFP gene is regulated by the control region of the ara operon. Ampicillin is an antibiotic that kills E. coli, so if E. coli, so if E. coli cells contain the ampicillin-resistance gene, the cells can survive exposure to ampicillin since the ampicillin-resistance gene encodes an enzyme that inactivates the antibiotic. Thus, transformed E. coli cells containing ampicillin-resistance plasmids can easily be selected simply growing the bacteria in the presence of ampicillin-only the transformed cells survive. The ara control region regulates GFP expression by the addition of arabinose, so the GFP gene can be turned on and
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.
The purpose of this experiment is to make E.Coli competent so that it can be transformed in order to become immune to ampicillin, then we would be able to determine the transformation efficiency of the culture. We determine this by preparing 4 plates of E.coli, each labeled “LB-plasmid”, “LB+plasmid”, “LB?Amp-plasmid”, and “LB/Amp+plasmid”. This meant that either should have lacked plasmid and Ampicillin, with plasmid but lacked Ampicillin, without plasmid but with Ampicillin, or were with Ampicillin and plasmid, respectively. Then we made the bacterial cells competent by adding CaCl2 to 2 vials of the colony (one with plasmids), and incubating on ice, then heat shocking, and returning to ice. Luria Broth is then added and left to sit for 5-15
The purpose of this experiment was to show the genetic transformation of E. coli bacteria with a plasmid that codes for Green Fluorescent Protein (GFP) and contains a gene regulatory system that confers ampicillin resistance. A plasmid is a genetic structure in a cell that can replicate independently of chromosomes. In this lab, the Green Fluorescent Protein, which is typically found in the bioluminescent jellyfish Aequorea Victoria, was cloned, purified, and moved from one organism to another with the use of pGlo plasmids. It was hypothesized that if bacteria that were transformed with +pGlo plasmids are given the gene for GFP, then transformed cell colonies
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 field of biotechnology involves the concept of genetic engineering, altering the DNA/genetic material of an organism using information from a different one. The process in which bacteria can obtain this manipulated genetic information from another source is called genetic transformation. The goal of this experiment was to genetically transform Escherichia coli bacteria’s DNA by inserting the vector pGLO plasmid which codes for ampicillin resistance as well as the green fluorescent protein, GFP. For the experiment, the E. coli bacteria were separated into two groups; control and
It will also highlight how successfully integrated plasmids can affect the cell and what proteins are produced by the DNA, and how easy it is to change the genetics of cell and the future generations of that cell. The experiment also demonstrates how natural selection would work in a lab environment, and how the addition of a gene or a mutation can protect an organism from adverse conditions in the environment. This lab also illustrates the change in DNA in a visual sense. Molecular genetics is a very small scale science that cannot be seen by the human eye, however by illuminating the bacteria with the GFP it will produce the very small process can be clearly seen before and after the genetic splicing. The bacteria will produce quickly and the successful bacteria will be clearly seen by the human eye, even after generations upon generations of bacteria.
To do a transformation one micro test tube was labeled +pGLO and the other was labeled –pGLO, using a transfer pipette 250 µL of transformation solution was added to each tube in the foam rack. The tubes were then placed on ice for three minutes. During these three minutes, a sterile loop was used to pick up a single colony of E. Coli from the starter plate by gently running the loop over the agar. This loop was then inserted into the +pGLO tube and the loop was spun until the entire colony dispersed. Using a different sterile loop, the same procedure was used for the –pGLO tube. After both tubes had their own colony of E. Coli, they were placed on ice for another three minutes. DNA plasmid was added to the +pGLO tube by taking a new sterile loop and immersing it into the stock tube creating a film across the loop then inserting
This experiment was performed to assess the efficacy of genetic transformations on bacteria via plasmid DNA coding for ampicillin resistance and green fluorescent protein. Genetic transformation was studied by taking transformed and untransformed Escherichia Coli (E. coli) and placing them on various media to observe gene expression via growth and color under UV light. The transformed E. coli were able to grow on ampicillin while the untransformed E. coli, which lacked the plasmid genes for ampicillin resistance, only grew on nutrient broth. In the presence of arabinose, the transformed E. coli glowed green. These results support the previous scientific understanding of bacterial competency, vectors, and gene expression and support gene transformations as an effective method to transfer the desirable DNA of one organism into another organism’s DNA. These results can be applied to real world issues such as medical treatments, food production, and environmental conservation.
In 1928, Fred Griffith first discovered genetic transformation by infecting mice with unencapsulated and non-pathogenic pneumococci (Lacks 2003). This was the start that opened up the field of biotechnology. Genetic transformation is a process where foreign DNA crosses a membrane of another cell and then alters the genetic material (Encyclopædia Britannica 2015). Genetic transformation can occur in a few different ways: projectile bombardment, electroporation, and heat shock (Weedman 2015). Heat shock is defined by increasing the temperature of cells environment making the plasma membrane become more permeability allowing new DNA to transfer into the cell (Weedman 2015). The cell receiving the new DNA, also known as competent cells, can either amplify the DNA or clone the DNA (JoVE 2015). The most common type of DNA used to perform genetic transformations is plasmids: small, round DNA molecules that still contains two strands of DNA that has the ability
This was done by using DNA ligation and E.Coli transformation. We looked at agar plates to analyze which one of E.coli cell strains took up the vector alone of the vector containing the gene of interest. Four agar plates were used in this laboratory which were labeled Ligation, pGEM- T Positive Control, Competent Cells Negative Control, and Competent Cells Positive Control. Reagents were used such as DNA Ligase Buffer, SOC Media, Ampicillin, IPTG, and X-Gal. Ligation was performed using 2X ligation buffer, DNA Mix, T4 DNA Ligase and sterile dH2O. Then the transformation of E. coli occurred in which our 4 LB agar plates were prepared with the corresponding amount of IPTG, X-Gal and ampicillin gene. The next step was pipetting the content into the corresponding plates and SOC media was added.The transformation tubes consent were placed on the agar plates using a spreader. The plates were incubated at 37 Celsius and then will be stored at 4 degrees Celsius.The ligation plate was prepared by adding 100 µL of IPTG, 50 µL of X-Gal and Ampicillin. In the ligation plate, the expected color to be see was blue. However, in our ligation plate, we were seeing both blue and white colonies. Blue cells indicate that the cells take up the vector alone in the presence of IPTG and X-Gal due to Beta- Galactosidase expression. IPTG or
Bacterial transformation is the process of moving genes from a living thing to another with the help of a plasmid.The plasmid is able to help replicate the chromosomes by themselves; laboratories use these to aid in gene multiplication. Bacterial transformation is relevant in everyday lives due to the fact that almost all plasmids carry a bacterial origin of replication and an antibiotic resistance gene(“Addgene: Protocol - How to Do a Bacterial