Phage Lab Report

6. Humans should not be concerned about the bacteriophages infecting other cells because each bacteriophage is particular to a certain bacteria. If the bacterial cell exhibits traits that are desirable to the certain bacteriophage, then the phage will chose to bind and infect it, otherwise people have nothing to worry about.

There are many reasons for identifying an unknown bacterium. The reasons range from medical purposes, such as determining if the unknown could cause ailments in living things or knowing what microorganisms are needed to make antibiotics. The experiment was done by applying methods in order to identify an unknown bacterium.

After precisely conducting the experiment and tabulating the results, data for Paraquat toxicity upon P. vulgaris plants can be interpreted over several different parameters. The parameters by which Paraquat toxicity was examined within this experiment involve visual observations, x-ray diffraction, chlorophyll concentrations, protein concentrations, and lastly malondialdehyde (MDA) concentrations on a per mg of protein basis. As stated before Paraquat is very widely used herbicide known to produce superoxide anions leading to chloroplast membrane damage and ultimately a variety of adverse effects upon the host organism, in this case P. vulgaris (Chia et al., 1982).

Titer of the Bacterial virus, the Measurement of the Recombination and the Reversion Rate, and the Gene Map Distance (Phage Recombination)

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

Citrobacter Freundii is a species of bacteria that can be potentially harmful to humans. It is known to cause meningitis by protruding into the brain and replicating itself (1). The Citrobacter species has also been found as a cause of some urinary tract infections, diarrhea, and even gastrointestinal diseases and symptoms (3). C. Freundii can be located in a wide variety of soils and water (3). Lastly, it is also the cause of many nosocomial infections due to its presence in water (1).

Bacteriophages were first discovered about 100 years ago by Frederick Twort and Felix D'Herelle. Bacteriophages or commonly known as “phages” are viruses that infect bacterial hosts. Bacteriophages come in multiple shapes and sizes. But a good amount of them are tailed viruses that contain double stranded DNA. The head of the bacteriophages has a protein shell which is attached to the tail. Some phages differ as some don’t have double stranded DNA they may be single stranded. Phages are incapable of reproducing on their own. In fact, they need a bacterial host to reproduce. Like any virus, bacteriophages are very fixed to discrete hosts. The host bacteria that we are using is called arthrobacter. Arthrobacter is a genus of bacteria found in soil (Pope et al 2016). Arthrobacter can help reduce hexavalent chromium which can cause some symptoms such as irritations to humans. Hexavalent chromium may also cause lung cancer if inhaled. The SEA PHAGE project was broken down into two parts. The first part which we are currently doing is isolating, purifying and amplifying the bacteria from our soil samples that we collected in the beginning of the year.

The main objectives of this experiment included making dilutions of solutions, plating phage or bacteria, and determining the number of bacterial viruses or phage in a suspension. It was also conducted to demonstrate that two different mutants of phage T4 can exchange genetic material to give rise to wild-type phage. The experiment was used to distinguish mutants from wild-type by their host specificity. The recombination in bacteriophage was performed to determine the concentration of unadsorbed phage from the U series plates, total concentration from B series, and concentration of

The bases of this experiment was to discover the identify of the unknown from three possible specimens: Klebsiella pneumonia, Escherichia coli, and Enterobacter aerogenes. Utilizaing the T streak technique, the bacteria was isolated into pure colonies for further study. The Gram Stain method was used to identity the morhphology of the bacteria such as the shape and whether the bacteria was Gram positive or Gram negative. Biochemical test were also used to help identify the unknown bacteria. The biochemical test used was the Triple Sugar Iron Agar, Sulfur Indole Motility test, Methyl Red test, Voges-Proskauer test, Citrate test, Urease test, and the Gelatin test. After observing the morphology of the bacteria using the Gram Stain method and utilizing all the possible biochemical test, the bacteria was identified to be Enterobacter aerogenes.

Escherichia coli, or E. coli, is a common bacterium that can be found in diverse environments all over the planet, including the gastrointestinal tracts of animals and humans. Many of these strains of E. Coli are essential mechanisms in the digestive tract, while others are pathogens that can cause complications in urinary and intestinal tracts. (Payne & Sparks) In research, E. Coli is commonly used as a model organism, meaning they are widely studied by scientists for a variety of purposes due to their experimental advantages. E. Coli is comparatively simple, and there are many advantages to studying these prokaryotic cells in the fields of biochemistry and molecular biology. E. Coli has this simplicity and is relatively easy to propagate in a lab environment. Their genome has been completely sequenced and many things we know about DNA, protein synthesis, and gene linkage have been derived from studies regarding this particular organism. (Cooper)

E. coli or Escherichia coli is a prokaryotic cell found the in lower digestive track of mammals and other warm blooded animals. E. coli is an easy bacteria to work with as it doubles quickly and is relatively easy to grow, millions of cells can be grown in several hours. E. coli is an ideal bacteria in the lab because it does not require its temperature to be too hot, too cold, or too precise. A general warm temperature is perfect for this bacteria. E. coli is also easy to care for it does not need a specific type of nutrient, in a lab setting it can be feed any agar, making the bacteria over all cheaper to care for. Strains of E. coli can also operate in aerobic or anaerobic environments.

In our experiment we are using one of three methods to inject the E.coli bacteria with

A highly conserved gene will be used to identify a prokaryotic species isolated from the body. Fundamental lab techniques will be also explored and utilized, such as amplifying using PCR, cloning, and transforming the gene into a host cell. DNA electrophoresis and specific substrate plating will serve as analysis check points. The final product will be sequenced and compared to similar species to observe phylogenetic relationships.

It was not until about a century ago that microbiologist Félix d’Herelle, discovered that phages can indeed help fight diseases; his experiment, isolating phages by passing feces through a filter, was used to help cure patients with dysentery (Kirby and Barr, 2013). The clear fluid was mixed with some bacteria named Shigell (Zimmer, 34). Little did he know that his work is the ground work for modern phage therapies (Kirby and Barr, 2013). d’Herelle had a probable thought that the phages do not kill their host (Kirby and Barr, 2013). To test the safety of phages, d’Herelle ingested them and injected them into his skin and confirmed no sicknesses occurred (Zimmer, 36). He was correct because today it is known that phages turn into prophages, which simply allows changes the host cells genome (Kirby and Barr, 2013); virus and host combine (Zimmer, 36). However, with recent research, uncertainty in the impacts of phage and host interaction have be discovered. It is not known how outside variables effect these interactions and that is why phage therapy should be taken with

In this lab experiment, students had to create a growth curve for E. coli. The E. coli growth curve would illustrate the progression of the population of E. coli a set time period. In this case, the growth curve depicted the population of E. coli over a 12-hour period. The growth curve for E. coli was created from the absorbance levels, the optical density(OD), recorded from the spectrophotometer.