Identifying Salmonella Choleraesuis Essay Example for Free

Identifying Salmonella Choleraesuis Essay The purpose of this study was to determine what an unknown bacteria was using several different microbiology lab techniques including an API test, an oxidase test, a gram stain, a hanging drop slide, and morphology identification. The unknown bacterium, which was contaminated with Serratia marcescens, was isolated by streaking the bacteria solution to single colonies. The isolated unknown white bacteria, had the appearance of circular form, convex elevation, entire margin, elongated cocci. The tests than showed that the bacteria was gram-negative, non-motile, and was identified as a Salmonella species bacteria, Salmonella choleraesuis. Introduction When applying biology to real world cases, it takes numerous tests to be able to identify exactly what a type of bacteria an unidentified bacterium is, whether it is a bacterium that is causing a person to be ill or a bacterium that is being studied in a laboratory. Often times a bacteria is taken from a contaminated sample that may contain more than one type of bacteria and therefore the specific bacteria that is to be identified has to be isolated. This can often be done by streaking the sample to single colonies. The individual colonies can then be put through several different tests that allow one to identify distinctive aspects of the bacteria. Some examples of these tests are a gram-stain and an API test. These tests allow one to figure out what properties a bacteria strain contains, such as gram negative or gram positive with the gram staining test, or what bacteria an unknown is based on positives and negative of the API test. The results of API tests, will show extremely accurately what a bacteria is based on previous tests performed. One such bacteria than can be identified is Salmonella choleraesuis. There have been many studies done where the particular strain of Salmonella needed to be identified so that a vaccine could be found. In one such study, the strain of Salmonella Choleraesuis had to be identified in order to then use live Salmonella choleraesuis to reduce the seroprevalence and the number of Salmonella carrier pigs at slaughter (Schwarz et al, 2011). By being able to identify the specific strain of the species Salmonella, scientists were about to prevent Salmonella from being passed on through pigs because of the Salmonella choleraesuis vaccine. Identification of a specific bacteria can help scientists make so many improvements in getting rid of deadly bacteria. Materials and Methods This lab was performed over several different days in order to utilize several different techniques in identifying the unknown bacteria. A tube that contained a red species S. marcescens and a white unknown bacteria was streaked to single colonies onto an agar plate using an inoculating loop. The plate was placed in the 37Â ° incubator for 24 hours. Once incubation had occurred the single colonies were used for the different microbiology lab techniques. The first of these techniques used was to determine what the morphology of the unknown bacteria was. The second of these tests was a gram stain. This test was done in order to determine if the unknown bacteria was gram negative or gram positive. The third technique used was a hanging drop slide, which was prepared using another single colony and a light microscope at 100x resolution, in order to observe the bacteria’s motility. The fourth test used was an oxidase test, which was also performed using another single colony of the unknown bacteria. This was done by placing the bacterial colony on filter paper and adding drops of oxidase reagent. The filter paper was then observed to see if it changed blue or not, in order to see if the bacteria produced cytochrome c oxidase. The final test used in the experiment was an API test. To begin the API test, a solution with bacteria and 5 mL of sterile saline, had to be made with a turbidity the same as the McFarland No. 3 (BaSO4) standard. This was done by adding loopfuls of bacteria to the saline solution, mixing the solution on the vortex, and then comparing the turbidity to the McFarland No. 3 standard, until the tubes were both at the same cloudiness. This created solution was then used in the API test by adding specified amounts to each of the microtubes on the API strip. For each of the microtubes whose names were not underlined or boxed, the tubes were filled to where the microtubes met the capsule. In the microtubes whose names were underlined, the microtubes were slightly underfilled, and then the capsule was filled with mineral oil in order to create and anaerobic environment. The last of the microbes were the ones whose names were boxed. In each of these the microtube and the capsule were filled all the way up with the bacteria. The API test strip was then placed in the 37Â °C incubator for 20 hours. After this time, observations were made about each of the different microtubes based on a given summary of results chart for the API test. A select number of microtubes had to have a few reagents added such as 10% ferric chloride, Barritt’s A and B solutions, Kovacs’ reagent, nitrate test reagent, zinc, and hydrogen peroxide, in order to see how the specific microtubes reacted at that time. Once the API test was performed, the negatives and positives found for each of the microtubes was used to identify the unknown bacteria using an identification table that showed the positives and negatives of many known bacterias. Results In the first part technique used in the lab, the morphology of the unknown bacteria colonies was found to be circular form, convex elevation, and entire margin. The second technique used, gram-staining, produced pink bacteria, which had the appearance of elongated cocci. The pink color indicated that the unknown bacteria was gram-negative. In the third technique, the hanging drop slip, there was not true motility and instead only Brownian movement. In the fourth technique, the oxidase test, the filter paper did not turn blue. In the final test, the API test, the results (Fig. 1) shows that the unknown bacteria being studied was Salmonella species, or more specifically, Salmonella choleraesuis. (Fig. 1) The API strip results after 20 hours of incubation at 37Â °C Discussion Through the use of the API test, the results most accurately showed that the bacteria was Salmonella species. This is what the bacteria was, however, it was a specific kind of Salmonella, S. choleraesuis. In the results of the tests, there were four different microtubes that contained different results than in the identification table. In each of the these cases, the API test showed positive results when the table showed negative results. Just because these didn’t match exactly, didn’t mean that the experiment didn’t work right. Each organism is different and because of this will have different reactions at times. In each of the cases, there was a small percentage that the results would be different than the identification table said it would be. With that, the Salmonella species all together was able to be identified better because, in general the different strains of Salmonella each come from the same species. There could also have been slight error when the mi crotubes were filled up. There may have been times when the tubes were overfilled or underfilled or air bubbles may have gotten into the tubes changing the results. Overall, the results were fairly accurate since the Salmonella species was able to be identified. The other tests used in the experiment were also useful in helping identify that S. choleraesuis was the unknown bacteria. It can be shown through previous tests that S. choleraesuis and Salmonella strains have similar characteristics to those found from the techniques used in this lab. In several cases it is shown that Salmonella strains are gram-negative (Kempf et al, 2012). The fact that S. choleraesuis fit the characteristics of previous studies helps show that bacteria was found correctly when preforming the different techniques. References Agbor, T. A., McCormick, B. A. (2011). Salmonella effectors: Imortant players modulating host cell function during infection. Cell Microbiology , 13 (12), 1858-69. Schwarz, P., Kich, J. D., Kolb, J., Cardoso, M. (2011). Use of an avirulentlive Salmonella Choleraesuis vaccine to reduce the prevalence of Salmonella carrier pigs at slaughter. Vet Rec , 21 (169), 553.

Vague Descriptions in Joseph Conrads Heart of Darkness Essay examples

Vague Descriptions in Heart of Darkness       A dark, unfamiliar setting and a suspenseful plot give Heart of Darkness the characteristics of a good novel, but what really stands out is Conrad's writing. The story is full of vague imagery and descriptions that the reader must contemplate in order to fully understand. Writing so vividly was an impressive feat for Conrad, who was actually not a native English speaker. (Dintenfass) His style includes a great deal of subtlety and complexity. Although it may seem as if Conrad was trying to confuse the reader, his actual goal was to create a work of art, rather that just a novel. Several critics have put down Conrad's work because his writing is so vague; they claim that it lacks order and clarity. Conrad occasionally wrote back to these critics and explained why he chose to construct his stories in such a vague manner. Says Professor Mark Dintenfass, commenting on Conrad's own opinion about his writing: "For Conrad then, as for most modern artists, the world as we experience it is not the sort of place that can be reduced to a se...

Birth Control vs. Contraception

According to Kippley & Kippley (1996), birth control is defined as a procedure of one or more medications, devices or actions followed so as to intentionally reduce or prevent the possibility of a woman being pregnant or giving birth. The term birth control is frequently used synonymously with such terms as contraception, family planning and fertility control. However, birth control includes abortion to prevent a birth, while family planning methods clearly do not consist of abortion.Methods that are meant to reduce or lessen the possibility of the fertilization of an ovum by a spermatozoon might be more particularly be called contraception. Contraception is different from abortion in that contraception prevents fertilization whereas abortion ends an already recognized pregnancy. Procedures of birth control that might prevent the implantation of an embryo if fertilization takes place are medically considered to be contraception but typified by several adversaries as abortifacients. R iddle (1999) said that oral contraceptive pill is considered to be the most popular kind of birth control.There are various brands of the pill and they come in packs of 21 or 28 pills. One pill is taken every day. The first 21 pills have a combination of synthetic estrogen and progesterone hormones. The oral contraceptive pill stops ovulation, stopping the ovaries from releasing eggs. Moreover, the pill likewise thickens cervical mucus, making it harder for sperm to enter the uterus. Then, the hormones in the pill prevent fertilization. The pill is 92-99. 7% effective as birth control. In addition, it does not protect against reproductive tract infections, including HIV/AIDS.Meanwhile, Riddle (1999) also maintained that condoms are called barrier methods of birth control because they put up a block, or barrier, which keeps the sperm from reaching the egg. Only latex or polyurethane (because some people are allergic to latex) condoms are proven to help protect against STDs, including HIV. HIV/AIDS Greener (2002) asserted that human immunodeficiency virus or HIV is considered as a retrovirus, which causes acquired immune deficiency syndrome (AIDS). AIDS is a condition in humans wherein the immune system starts to fail causing life-threatening opportunistic infections.Infection with HIV happens by means of the transfer of semen, vaginal fluid, blood, Cowper's fluid or breast milk. Within these body fluids HIV is present as both free virus particles and virus within infected immune cells. The three primary routes of transmission are unprotected sexual intercourse, contaminated needles and transmission from an infected mother to her baby at birth or by way of breast milk. Screening of blood products for HIV in the developed world has largely get rid of transmission by means of infected blood products or blood transfusions.HIV has been discovered at low concentrations in the urine, tears, and saliva of infected humans; however, the risk of transmission by these secr etions is insignificant. At present, there is no vaccine or cure for HIV or AIDS. The only recognized means of prevention is evading exposure to the virus. Nevertheless, an antiretroviral treatment, known as post-exposure prophylaxis is said to reduce or lessen the risk of infection if started instantly after exposure. Recent treatment for HIV infection includes highly active antiretroviral therapy, or HAART.This has been extremely beneficial to numerous HIV-infected individuals since its introduction in 1996, when the protease inhibitor-based HAART initially became available. Present HAART options are combinations (or â€Å"cocktails†) consisting of at least three drugs belonging to at least two types, or â€Å"classes,† of anti-retroviral agents. According to the Joint United Nations Programme on HIV/AIDS (UNAIDS), HIV infection is now pandemic. In fact as of January 2006, UNAIDS and the World Health Organization (WHO) approximate that AIDS has killed over 25 million individuals ever since it was first identified on December 1, 1981.This makes the disease one of the most destructive pandemics in recorded history. In fact, in the year 2005, AIDS claimed a projected 2. 4 to 3. 3 million lives of which over 570,000 were children. References Greener, R. (2002). â€Å"AIDS and macroeconomic impact†, S, Forsyth (ed. ): State of The Art: AIDS and Economics, IAEN, 49-55. Kippley, John, Sheila Kippley (1996). The Art of Natural Family Planning, 4th addition, Cincinnati, OH: The Couple to Couple League, 108-111,148.

Analysis Of The Book Celia A Slave - 1267 Words

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