The Symbiotic Relationship Between a Bacteriophage and the Mucus Layer of a Metazoan Host

5 drops of chloroform were added to the mixture and incubated at room temperature for 15 minutes to kill, and lyse the bacteria cells which allows all the unadsorbed phages to be accounted for when determining the titer of unadsorbed phage with susceptible bacteria, E. Coli B. (Biology Dept.). 0.1 ml of E.coli B was added to the 10 fold dilution. Using soft agar technique, the unadsorbed phage were plated. After incubation, the titer of unadsorbed phage was determined by counting the number of plaques on the plate from the infection of single E. coli cells in the assay tube by a free phage particle before

IgA – antibodies that are secreted across mucus layer to prevent microbes from penetrating cell bodies

7. List several functions for the outer membrane in gram-negative bacteria. What is the chemical composition of the outer membrane?

Some phages infect bacteria to destroy them, which is called lysic lifestyle, while other phages infect bacteria and stay dormant inside them for a while, which is referred to as a lysogenic lifestyle. A phage infects the bacteria cell by injecting its genetic material into the bacteria’s cytoplasm. This allows the bacteria synthesis process to start making the phage’s genetic code instead of its own. Once the bacteria have made enough phages to handle, the walls will break and release all of the phage that was created. The phages that were made are now resetting the process and beginning again by infecting the other near bacteria by injecting their genetic material once again. Those phages that stay within the bacteria and not burst the bacteria will continue to reproduce the phages own genetic code. (Griffiths,

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

Most pathogens prefer to grow in pH neutral conditions; many of the cavities in the body are protected from an invasion by a high pH. An example of this is the stomach, which is very acidic and kills ingested pathogens.

When attempting to colonise mucosal surfaces of the upper respiratory tract, N. meningitidis must use adhesins such as pili and opacity proteins to interact with host cells and adhere to tissue.

These droplets enter the nasal cavity of a second host where small hairs and a mucus membrane are present. They trap microbes before they can penetrate further into the body; however some microbes evade capture and continue into the lower respiratory tract. The respiratory tract, consisting of mucus and ciliated epithelial cells, catches more foreign particles and sweeps them up and out towards the pharynx (see Figure 1), where it is swallowed in to the stomach. The gut flora within the stomach secretes chemicals such as lactic acid which lower the pH,

8. Eventually the bacteriophages will die in the intestine since there will be no more bacteria to combat and live off of.

Based on research and observation, we now know that infectious diseases are caused by microorganisms (pathogens) and that the immune system provides defense against infectious diseases.

Imagine the bacteria as robbers trying to invade a house, the body in this analogy. The immune system is the police officers in charge of the house, and the meninges are the alarms around the point of the house that the robbers want to come in through. The robbers trick the police officers into helping them rob the house. The robbers used the police officers, originally intended to do good.

Additionally, I have pushed myself to take the most rigorous courses that my high school offers, not only in attempt to prepare myself for my future, but also for my love of learning. In particular, I decided to take an independent study this year. I wished to utilize this opportunity as my first step into what I wanted to pursue in the next chapter of my life. Thus, I planned to venture into both viruses and bacteria, as well as other pathogens such as

Virulence Factors: The most important virulence factor of S. aureus is the specific surface proteins that allow the organism to attach to host proteins. The surface proteins of this bacterium allow it to attach to host proteins such as laminin and fibronectin, which form the extracellular matrix of epithelial and endothelial cells. S. aureus also produces a number of membrane damaging toxins that allow the organism to further invade and harm the host, of which the alpha- toxin is the most well studied and is the protein responsible for septic shock. The alpha- toxin is a protein that binds to a specific receptor in platelets and monocytes in humans, forming pores that eventually destroy the cell.

Distinctions in the micro-organisms structure can be pivotal to not only the function of the pathogen within the body, but also the means by which it may spread.

aureus for the same ecological niche causing the amount of S. aureus present to be kept at a manageable level for the child to handle. The two opportunistic pathogens may even be causing virulence of one another through this competition. If this is the case than non-virulent H. influenzae may be able to be used as a possible way to exclude or at least lessen the amount of the S. aureus by inhabiting the nasopharynx, but not causing any symptomatic carriage. This may lessen the ability for the S. aureus pathogenicity by inhibiting the overdevelopment of the organism in this environment. In this study we will determine if the non-virulent strain is as effective in reducing the S. aureus pathogenicity in vivo by comparing both types of H. influenzae against the S. aureus. In this experiment we will use the Chinchilla model and employ healthy flora to out-compete an opportunistic pathogen, there is prior research that suggests that N. lactamica may be able to effectively compete with other pathogens such as S.