Neisseria gonorrhoeae Essay -- Essays Papers

Neisseria gonorrhoeae Introduction Neisseria gonorrhoeae is the obligate human pathogen that causes the sexually transmitted disease (STD) gonorrhea. This Gram-negative diplococci/gonococci does not infect other animals or experimental animals and does not survive freely in the environment. The gonococcal infection occurs in the upper or lower tract, pharynx, ophthalmic area, rectum, and bloodstream. During the 1980’s gonorrhea was also referred to as â€Å"the clap† when public awareness was quite minimal. This was one of the venereal diseases prostitutes hoped to contract since it resulted in infertility by pelvic inflammatory disease (PID). As documentation, diagnostic testing, and public awareness improved, there has been a decline in incidence reports, however, it is still considered a very common infectious disease. Encounter Sexually active men and women of all races, ages, and socioeconomic backgrounds are susceptible to the gonococcal infection. However, out of the infected population, the CDC states 80% of the females and 10% of the males are asymptomatic. After incubation of five to seven days, males tend to display symptoms of swelling in the urethra, painful and more frequent urination, and abnormal penal discharge of a thick yellow exudate (pus). Similarly, females experience chronic abdominal pain, inflammation of the cervix, painful urination, bleeding or irregular menstrual cycles, fever and increased vaginal yellow discharge. Females have a higher risk factor of 60-90% of being infected after a single sexual encounter. Both sexes experience sore throat in oral infections if they are not asymptomatic. However, this response is most commonly mistaken as a viral sore throat. Entry Neisseria gonorrhoe... ...584.doi: 10.1046/j.1462-5822.2002.t01-1- 00215.x Park, Hae-Sun Moon, Wolfgang, Matthew, van Putten, Jos P. M., Dorward, David, Hayes, Stanley F. & Koomey, Michael. Structural alterations in a type IV pilus subunit protein result in concurrent defects in multicellular behaviour and adherence to host tissue. Molecular Microbiology 42 (2), 293-307.doi: 10.1046/j.1365-2958.2001.02629.x Soper, David E, Disseminated gonococcal infection. (Protocols). Contemporary OB/GYN. June 2002 v47 i6 p135(4) Bradbury, Jane. Neisseria gonorrhoeae evades host immunity by switching off T lymphocytes. The Lancet. Feb 23, 2002 v359 i9307 p681. Senior, B.W., Steward, W., Galloway, C., Kerr, M. Cleavage of the Hormone Human Chorionic Gonadotropin, by the Type 1 IgA1 Protease of Neisseria gonorrhoeae, and Its Implications. Journal of Infectious Diseases. Oct. 1, 2001 v184 i7 p9022.

Importance of Research Essay

In sending a letter of inquiry, there are considerations that can be established to let the grantor consider the intent for research. The letter will present the main design of the research process which will use the correct psychological metrics in assessing the different attributes of characters. Basically, the first approach is to establish the reference for the identification of counseling techniques. The research will have a conclusive parameter in which the measurements will be undertaken when the actual data collection starts. This will at least create a platform in order to correlate the results of the study and the actual accepted standards used in the counseling industry. Since the main study involves counseling, there should be a standardized basis as to how to interpret client reactions. By the time the metrics are formulated, an actual data gathering will be done using the techniques of survey modeling. A random generation of respondents can be initialized using sampling methods on statistics. Depending on the scope of the study, a particular segment of the population may be used. For example, separate studies can be done according to gender, income, medical history and age. The survey will seek the impressions of selected respondents based on how counseling can influence their decision making capability. The subject will first undergo a counseling session with a designated psycho-analyst and will then be interviewed to get info about the effects of counseling to their attitude and perception in life. In terms of ethical considerations, the real approach of counseling will be used. Since the research will be looking for generative factor effects, then a credible counselor will be hired for the project. Of course, it would be unethical to provide counseling suggestions to the respondents based only on fictional approaches. It may induce them to actually modify their opinions which may create certain dilemmas in their lives. Another ethical aspect may involve the process of disclosing the research process to the respondents. It is very possible that they will provide personal details and opinions within the counseling activities hence compromising their privacy. In order to stay away from possible legal suits, the respondents may be informed of the research. Giving them the assurance of the credibility of the counseling results and their privacy will be of utmost importance. To persuade the grantor, related studies can be presented. Of course, these documents should present the positive outcomes of previous researches which have already made its way on implementing a decision based on the research results. It would be best to inform him that research establishes the technical aspect of proving or disproving a particular â€Å"guess† about a certain interest. No mater what the outcome would be, a research study will let an initiator to improve a certain goal or to divert its intention to prevent a possible contrasting scenario. Just like in the profession of counseling, a researched standard approach for specific clients can optimize the goal of assisting them in resolving their personal concerns. Practically, a research sustains the need for a good and quality knowledge. Even large scale educational institutions agree that research studies play an important role in knowledge development (IDS, 2008). A segmented report from the involved colleges and universities may be submitted to the grantor to inform him of the basic necessity for research studies. References IDS. 2008. Big Ten universities affirm research importance. Indiana Daily Student. Retrieved January 19, 2008 from http://www. idsnews. com/news/story. aspx? id=48060&comview=1

Extraction and Characterization of Bacterial DNA - Free Essay Example

Sample details Pages: 6 Words: 1765 Downloads: 1 Date added: 2019/03/18 Category Analytics Essay Level High school Tags: Characterization Essay Did you like this example? ABSTRACT: In this experiment, deoxyribonucleic acid (DNA) was extracted from Micrococcus lysodeikticus, a bacteria with a high guanine and cytosine content. The standard method of chloroform-isoamyl alcohol extraction was used, and the DNA was solubilized in Tris buffer. The DNA was then quantified and qualified using UV spectrophotometry. Don’t waste time! Our writers will create an original "Extraction and Characterization of Bacterial DNA" essay for you Create order The DNA was determined to have been extracted in relatively high amounts, but the purity was lacking, especially in regards to ribonucleic acid contamination. The hyperchromic effect was utilized to gauge the purity of the DNA. Future studies will focus on the ecologically safer and more efficient methods of DNA extraction. Key Words: Ribonuclease, RNA, DNA, DNA structure, bacteria. Deoxyribonucleic acid (DNA) is the genetic material inside of a cell. The code of nucleotide base pair sequences allows for the cell to translate messages into proteins that can be used in all parts of the cell. DNA is a double helix that is composed of rungs being the base pairs that are hydrogen bonded together, and a sugar phosphate backbone that is covalently bound together1. This structure gives the DNA the strength yet flexibility it needs in order to be able to unzip so that the genetic material it holds can be accessed2. The complementarity of the DNA molecule is truly what sets the molecule apart from others. Even if the DNA is denatured and the hydrogen bonds come undone, because each base pair binds to only one specific type of other base pair, this phenomena allows the DNA to spontaneously come together again. The base pairs will line up with their respective pair due to the energetic favorability of having as many hydrogen bonds as possible2. Because of DNAs importance as a biological storage molecule, accessing the DNA trapped inside of the cells has become a main avenue of research for scientists. Depending on the organism, different solvents and methods can be used to yield the highest amounts and most pure DNA. Even within the same types of organisms, there may be different challenges that arise from a specific species. Specifically in bacteria, different strains can have higher or lower G+C content3. Because the guanine and cytosine nucleotides are bound together by three hydrogen bonds as opposed to the 2 that bind adenine and thymine together, the G+C bonds are more difficult to pull apart. This means that harsher solvents may have to be used in order to adequately extract and solubilize the DNA. When the DNA is extracted, it can be denatured as a way to assess its purity. The hyperchromic effect is a phenomena that occurs when DNA is denatured so that the two strands of the double helix come apart and assume a formation that is random and coiled4. Because there is much more surface area in the randomly coiled DNA than the uniform and compact double helix form, the DNA will absorb substantially more UV light at a wavelength of 260nm. In this experiment, the DNA of Micrococcus lysodeikticus was extracted using a chloroform-isoamyl alcohol method and was precipitated using cold ethyl alcohol. Following this partial purification of the DNA, the DNA was quantified and qualified using UV spectroscopy. The hyperchromic effect was employed to ascertain the purity of the DNA by denaturing the molecule using high tempertaures. EXPERIMENTAL PROCEDURES The experiment was conducted as described by Boyer2. To begin the experiment, a set amount of freeze dried bacterial cells of the species Micrococcus lysodeikticus were massed out and suspended in a set volume of saline-EDTA in a 50mL Erlenmeyer flask. An aliquot of 10mg/mL lysozyme was added to the bacterial solution and was incubated at 37? °C for 30 minutes. After the incubation, an aliquot of 25% sodium dodecyl sulfate was added to the mixture and was heated at 60? °C for 10 minutes, after which the mixture was cooled to room temperature. The mixture was then added to a Nalgene centrifuge tube. An aliquot of 5M sodium perchlorate solution was added to the solution, followed by a generous portion of 24:1 chloroform-isoamyl alcohol. This mixture was then gently shook for 20 minutes with gloves on so that the proteins in the mixture could be separated out. The solution was then placed in a refrigerated centrifuge at 7800rpm for 5 minutes. The aqueous upper layer of the mixture was then carefully transferred into another container, where ice cold ethyl-alcohol was gently poured over it in generous amounts in order to precipitate the DNA. The nucleic acids were then spooled and transferred to a set volume of Tris buffer. Once a sufficient amount of DNA had been spooled, the aqueous DNA mixture was split into two portions. In one sample, RNAse was added and inverted to mix. Both samples were then stored in a 4? °C refrigerator for one week, and the rest of the procedure was conducted. Both the DNA with and without RNAse were used to make separate dilutions so that the Absorbance at 260nm was approximately 0.400. From both of the dilutions, 2mL aliquots were added to microcentrifuge tubes, and the two different types of DNA solutions were treated in the same fashion. One sample was kept at room temperature, one tube was denatured in boiling water for 10 minutes and then left to cool to room temperature slowly, and the other tube was denatured in boiling water for 10 minutes and then placed in an ice bath to cool to room temperature quickly. Absorbance values were gathered from the room temperature samples at 260nm and 280nm. The absorbance for the room temperature sample at 260nm was recorded again at the end of the experiment. The sample that was heated and allowed to cool slowly had the first absorbance recorded immediately after it was taken out of the boiling water. Another 260nm absorbance value was taken after the sample had cooled down to room temperature. The sample that was heated and cooled in an ice bath had its absorbance measured after it was at room temperature. To analyze the data gathered from this experiment, the following two equations were used to determine how much DNA was isolated. Equation 1. Determining the concentration of the DNA solution. Equation 2. Determining the amount of DNA isolated. As a point of comparison, the theoretical amount of DNA that could be isolated from the mass of cells used was determined using the following. Equation 3. Determining the theoretical mass of DNA. Next, the following equation was used to determine the percent of the cells weight that is composed of DNA. Equation 4. Percentage of cell weight that is DNA Then the purity of the DNA could be determined given the ratio of absorbance at 260nm to the absorbance at 280nm.This also lends insight as to what possible impurities could be in the DNA, such as protein or RNA (ribonucleic acid). The following equation demonstrates the change in the absorbance values at 260nm to reflect what occurred in terms of the hyperchromic effect. Equation 5. Percentage of change in the absorbance values. DNA mass (g) Theoretical DNA mass (g) Percent Cell Weight (%) A260/A280 Percent Change A260 for Hot RT (%) Percent Change A260 for Hot-RT RT (%) Percent Change A260 for Hot-Ice-RT RT (%) DNA 1004 1787 0.75 2.71 12.5 -4.44 6.77 DNA with RNAse 794 4.51 31.2 -6.98 25.9 Table I. Summary of results from the spectrophotometry data collected regarding the DNA and DNA with RNAse. Equations 1 through 5 were used to determine the values listed in the table below. RESULTS The results of the experiment are listed in Table I. The calculations were performed for both the DNA samples and the DNA with RNAse samples. DISCUSSION In this experiment, various quantities surrounding the DNA sample were determined so that the amount of DNA and the purity of the DNA could be assessed. This was possible due to the scientific knowledge of the structure of DNA. The theoretical and actual masses of the DNA were very close to each other, indicating that a sufficient amount of DNA was isolated and the isolation process was performed accurately. Additionally, the percent cell weight was the same as the theoretical cell weight of 0.75%. However, the ratio of A260/A280 values lend insight as to the purity of the DNA, and the ratio is much higher than the pure DNA value of 1.90. This suggests that the RNAse was ineffective at removing an adequate amount of the RNA. However, the A280 value used seems to be skewed, so that it unnecessarily inflates the ratio. Further spectrophotometry would have to be done using the same DNA in order to determine the most accurate ratio for the sample. The hyperchromic effect took hold for both the sample that was boiled and quickly cooled and the sample that was boiled and the absorbance value was immediately taken. There appeared to be a large effect from the speed cooling versus the slow cooling, which makes logical sense considering that the more time given to the DNA to arrange itself back into its complementary sequence, the more precise and accurate job that the intermolecular forces will do. However, if the DNA is cooled quickly, it does not have time to rearrange precisely. Rather, the DNA could get stuck in tangles and therefore absorb more UV light that the normal double helix. While the chloroform isoamyl procedure that was used in this experiment was effective, it is important to always strive for more efficient and/or more ecologically friendly alternatives to hazardous chemicals. In a study by Cheng and Jiang, the researchers developed a method of DNA extraction that allowed to cut the time it takes to extract DNA from microbes in more than half, and also eliminated the need for a separate cell wall lysing agent5. Another reason to be on the lookout for different procedures for DNA extraction is due to the blossoming field of microbiome research. In a study by Knudsen et al, the choice of DNA extraction methods influenced the data that was garnered about the population in the microbiome6. Therefore, microbiome researchers must be cognizant of how experiments early on in the project could affect assumptions down the line. Reasons such as these mean that science must always be advancing into newer and better techniques. REFERENCES (1) Yakovchuk, P.; Protozanova, E.; Frank-Kamenetskii, M. D. Nucleic Acids Res. 2006, 34 (2), 564â€Å"574. (2) Boyer, R. Modern Experimental Biochemistry, 3rd ed.; Roberts, B., Lake, J., Prescott, M., Eds.; Benjamin/Cummings: San Francisco, 2000. (3) Sanders, C. A.; Yajko, D. M.; Hyun, W.; Langlois, R. G.; Nassos, P. S.; Fulwyler, M. J.; Hadley, W. K. J. Gen. Microbiol. 1990, 136 (2), 359â€Å"365. (4) Lara Castellazzi, C.; Orozco, M.; Amadei, A. J. Phys. Chem. B 2013, 117, 8697â€Å"8704. (5) Cheng, H. R.; Jiang, N. Biotechnol. Lett. 2006, 28 (1), 55â€Å"59. (6) Knudsen, B. E.; Bergmark, L.; Munk, P.; Lukjancenko, O.; Prieme, A.; Aarestrup, F. M.; Pamp, S. J. bioRxiv 2016, 1 (5), 064394.