Endospore-forming Bacteria and their Role in Biodefense Essay Example for Free

Endospore-forming Bacteria and their Role in Biodefense Essay Bacteria that have the ability to produce non-reproductive structures or endospores during unfavorable environmental conditions are termed endospore-forming bacteria. Two genera of bacteria in which sporulation are predominant are Bacillus and Clostridium. Bacilli are rod-shaped bacteria, species of which are either obligate or facultative aerobes. The genera include both free-living and pathogenic species. When conditions become unfavorable, the bacterial populations thrive by producing endospores or cysts which can remain dormant and viable for prolonged periods. The genera include several species such as Bacillus anthracis, B. coagulans, B. megaterium, B. cereus, B. globigii, B. natto, B. infernus, B. licheniformis, B. subtilis, thuringiensis, B. polymyxa and B. sphaericus. Of these, the most pathogenic ones are B. anthracis and B. cereus. B. anthracis causes anthrax. B. cereus causes a foodborne illness. B. subtilis and B. coagulans are microbes that cause food spoilage. B. thuringiensis, is an insect pathogen and is therefore a potential biocontrol agent, while B. subtilis is used as model organism in research. Clostridium is a genus of Gram-positive, rod-shaped bacteria, which are obligate anaerobes. They are also capable of producing endospores under stressful or unfavorable environmental conditions. Species include Clostridium acetobutylicum, C. beijerinckii, C. aerotolerans, C. bifermentans, C. chauvoei, C. botulinum, C. butyricum, C. difficile, C. formicaceticum, C. colicanis, C. laramie, C. perfringens, C. ljungdahlii, C. novyi, C. piliforme, C. phytofermentans, C. sordellii, C. scatologenes, C. tetanie, C. tyrobutyricum and C. sporogenes. Five species of this genus are highly pathogenic. These are C. botulinum, C. perfringens, C. tetani, C. sordellii and C. difficile. C. botulinum causes botulism by producing toxin in food or wound. C. perfringens causes varied disease symptoms such as food poisoning, gas gangrene, enterotoxemia in cattle. This species also causes food spoilage. C. tetani causes tetanus. C. sordellii is a microbe associated with deaths of women post childbirth. C. difficile causes pseudo-membranous colitis. Both these genera of gram-positive bacteria are capable of producing endospores in response to nutrient depletion. According to Liu et al (2004), spores are dormant bacterial morphotypes able to endure harsh environments for decades, thus making it easier to be formulated and dispersed as a biological weapon. B. anthracis spores are highly persistent and can simply be â€Å"weaponized† for routing through air, food or water. The formulated spores are usually dry and concentrated, which can reach the human body by inhalation, ingestion, or cutaneous contact and cause anthrax. Infection is severe upon inhalation on endospores of B. anthracis. When inhaled, the spores enter lungs and reach deep into the alveolar spaces. From there they traverse into the medistinal and peribronchial lymph nodes. Once they reach the blood stream, they begin to multiply by switching on to the vegetative cycle and produce toxins that are lethal (Young and Collier, 2002). These are potential biodefense agents because, B. anthracis endospores when dispersed in the air as 1-to-5- µm particles may create a threat over a larger geographical location. In Russia, an accidental release of endospores from a military biologic-weapons facility in Sverdlovsk caused anthrax in humans as far as 4 km from the site, and cases in animals extended as far as 50 km away (Swartz, 2001). The detection of anthrax spores is also not easy and technologically also it is not realistic for rapid in-place detection to be done (Webb, 2003). Nevertheless, when diagnosed immediately the severity can be decreased, administration of oral antibiotic prophylaxis during the incubation stage has proved to be successful. However, once the fulminant stage is attained, the disease is clear of treatment and without doubt lethal (CDC, 2002). According to Inglesby et al. (2002), vaccination is supposedly effectual but the drawback is that a series of six shots over 18 months followed by annual booster shots is a pre-requisite for complete immunity. Therefore, it is obvious that when used as a biological weapon, spores of B.anthracis are capable of inflicting immeasurable torment on man and animals. This elects it to be an ideal candidate for biodefense. References CDC. (2002). Public Health Emergency Preparedness and Response (November, 2002) www. bt. cdc. gov_agent_anthrax_index. asp. Inglesby, T. V. , O’Toole, T. , Henderson, D. A. , Bartlett, J. G. , Ascher, M. S. , Eitzen, E. , Friedlander, A. M. , Gerberding, J. , Hauer, J. , Hughes, J. , et al. (2002). Anthrax as a Biological Weapon, J. Am. Med. Assoc. 287, 2236–2252. Liu, H. , Bergman, N. H. , Thomason, B. , Shallom, S. , Hazen, A. , Crossno, J. , Rasko, D. A. , Ravel, J. , Read, T. D. , Peterson, S. C. , Yates J. and Hanna, P. C. (2004). Formation and Composition of the Bacillus anthracis Endospore. Journal of Bacteriology. 186 (1), 164–178. Swartz, M. N. (2001). Recognition and management of anthrax an update. N Engl J Med. 345, 1621-1626. Webb, G. F. (2003). A silent bomb: The risk of anthrax as a weapon of mass destruction. PNAS. 100(8), 4355–4356 Young, J. A. T. and Collier, R. J. (2002) Attacking Anthrax. Sci. Am. 286, 48–59.

Computers, the Internet, and a Changing World :: Computer Cyberspace Technology Essays

Computers, the Internet, and a Changing World When I think about the world of writing in the year 2003, and compare it to writing, let’s say, in the year 1990, the changes that have evolved are phenomenal. Of course, a person could argue that change is the one constant in life, including people, ideas, and technology, just to name a few. How can you measure and analyze every change that’s occurred in the world, and its cultures? If you tried, you’d likely grow old and die before you could pinpoint every single one. But when it comes to writing and the writers, themselves, in the twenty-first century, no longer are the paper pages of books, magazines, and newspapers the only source of reading. The internet is a dazzling and complicated electronic world, where one human can instantly communicate with another, all with the click of a mouse. Cyberculture has taken us from an earlier world, where we used the pen, pencil, typewriter, and just a computer, to a rapid-fire electronic galaxy, that enables us to use millions of pixels to send messages to the world; the most amazing part of all, is that we can do all this without ever leaving the comfort of our homes. Let’s start at the beginning, before the information superhighway was a part of the global vernacular. Millions of people like to read the newspaper, for a variety of reasons; many, including myself, want to keep up to speed on current events, locally, and around the world. I tend to read The Detroit Free Press, The Ann Arbor News, and occasionally, The New York Times, all good and, for the most part, accurate sources of news. My parents subscribed to all three newspapers for many years, and still do to this day. After I moved out and began living on my own, I would go to the nearest store or newspaper stand to buy a copy, and at times, still do this. However, with the explosion of internet usage, I don’t have to run out to the store and spend thirty-five or fifty cents on one of those papers; rather, all I have to do is turn on my computer, get connected to the internet, type in the URL, and I am instantly at that newspaper’s site, with that day’s electronic headlines only a few inches from my face. I can read the front page news, or click a link that takes me to the sports section, or hit another link that takes me to the movie reviews. There are countless texts, long and short, to read on the internet, and newspapers are only one example. However, I believe that these

Of Mice and Men Critical Evaluation Essay

Question: Write a critical evaluation of the novel â€Å"Of Mice and Men† in which you consider the setting, the plot and the author’s style as well as what you think the author was trying to get you to think about through the medium of the story. The novel, â€Å"Of Mice and Men† by John Steinbeck is one which I have read recently. The book is set in the outskirts of Soledad, California, America round about the 1930s. The two main characters of the novel are George Milton and Lennie Small. George is a small, quick thinking man and is the total opposite of Lennie whom is big built, and rather unintelligent and ‘simple minded’. When reading the book it appears as though he could possibly have a mental disability. In that particular time of the centuary is was rather peculiar for two men to be travelling around together. The two men migrate from a town called Weed, the reason for this being that Lennie touched a little girls’ dress as he liked to touch soft materials, this material being the little girls’ dress. Although the young girl claimed that Lennie had raped her and so George and Lennie fled the town. They worked as labourers and so migrated to a ranch near Soledad. At the ranch we are introduced to some other characters. One being Slim, a man who works at the ranch he appears a well respected man and is sort of looked to as the sort of leader of the group. Curley is the bosses’ son and enjoys picking fights with other men present at ranch and is rather disliked by most. Carlson is another man whom works at the ranch who becomes quite friendly with George and Lennie. Curleys wife is referred to as a tart on the ranch, she in known to have given some men the ‘eye’ without Curleys knowledge. Later in the novel Curleys wife is killed by Lennie due to her own careless actions when she flirts with him and torments him. She tells him to touch her hair as he likes to touch soft things. When she tells him to stop ‘mussing’ it up and he does not stop she reacts in a way that Lennie is startled and when she begins to scream he begins to panic and become scared and so he puts his hand round her mouth and lifts her up by the neck and shakes her. We are then told that ‘she flops like a fish’ and when Lennie drops her she land on a pile of hay and it is then we find out she is infact dead. In consequence to this incident Curley and some of the other men attempt to track Lennie down but George tells them that Lennie has gone South of Soledad but in actual fact he has given them the wrong directions because it is only George that knows where Lennie has really gone. When George finally reaches Lennie he decides that it would be better if he ended Lennies life for him rather than have Lennie being tortured and having to experience pain by the other men when they eventually hunted him down. In the novel there are lots of features which run through out the book. The features of the book which will be mainly focused on are the plot, the setting and the author’s style. The first feature which I will concentrate on is the plot. Lennie who is more like a young boy rather than a responsible adult, he likes to pet soft things for example when Slim gives him a puppy because his bitch has a litter of pups he pets it so much that he ends up killing it. An example of the plot is when Lennie is constantly petting the puppy and is warned by George who says: â€Å"‘You’ll kill him, first thing you know.'† The above example shows that Lennie was warned to stop petting the pup or it would result in its death but he is too persistent to stop. A second example of the plot occurs nearer the end of the novel when Lennie and Curleys wife are in the barn: â€Å"Then Lennie grew angry, â€Å"Now don’t,† he said. â€Å"I don’t want you to yell. You gonna get me in trouble jus’ like George says you will. Now don’t you do that.† And she continued to struggle, and her eyes were wild with terror. He shook her then, and he was angry with her. â€Å"Don’t you go yellin’,† he said, and her body flopped like a fish. And then she was still, for Lennie had broken her neck.† This example shows that Lennie was so terrified that he would go to any extent to prevent him from getting into trouble from George. Now that he had killed her he was clearly much calmer now that he had somewhat solved the problem which could have got him into trouble because Curleys wife was no longer an issue to cause any concern. These two examples both show how the plot develops through out the novel. I will now cover the setting which is one of the many other features running throughout the book. The book was set back in the 1930s at a ranch near Soledad in California, America. The first example I will direct my attention to is from the beginning of the novel and it says: â€Å"On the sandy bank under the trees the leaves lie deep and so crisp that a lizard makes a great skittering if he runs among them. Rabbits come out of the brush to sit on the sand in the evening, and the damp flats are covered with the night tracks of ‘coons, and the spread pads of dogs on the ranches, and with the split- wedge tracks of deer which come to drink in the dark.† This example descriptively tells of the surroundings in the novel. This is a good example as it describes the scenery in great detail to give a vivid image in the mind. Lastly, the authors style was another of the very many features of the novel. This style was brought to my attention many times due to the great depth of explanation. An example of this is: â€Å"The little evening breeze blew over the clearing and the leaves rustled and the wind waves flowed up the green pool.† This last example is effective as it describes how the wind blew across the pool. Most writers try their best to show great depth in their description, whereas Steinbeck shows his remarkable and impressive ability to create a descriptive atmosphere. In conclusion after reading the book I think the message that Steinbeck is trying to get across is that people who needed more help than others in those days were treated just the same as any other person. Also I think that Steinbeck would like people to know that America is not always the perfect place to be, as in the novel it shows some examples of racism, unfairness to women and inequality and many more issues. After all everyone has the right to an equal life and Steinbeck is trying to say that no matter how good people think America is its not always a fair society. I found the book very enjoyable but in some parts a little sad and it is most unusual to any other book which I have read. Towards the end I found myself empathizing with Lennie as I did not agree with the way in which his life was ‘stolen’ from him when it was not his fault that he had a somewhat mental disability.

Heroes Are Rare For A Reason - 1868 Words

Heroes are rare for a reason. One cannot simply deem themselves heroic, but must possess an array of qualities that juxtapose with their humanity and set them apart from the fearful and apprehensive predispositions so innate to the majority of humankind. In reality, true heroism is scarce. Men and women are highlighted and praised in modern media for acts of bravado, and rightly so, but only in literature can we find characters who so easily epitomize triumph through fantastical feats, who transform themselves and the world around them, and whose very names are synonymous with daring. The Greeks were particularly famous for depicting larger-than-life figures both real and unreal in their mythic lore that arguably defines the idea of epics in the minds of the Western world. To emerge victorious in their endeavors, these figures wielded arsenals of strong qualities to turn the tides of their unbelievable stories in their favor. In Homer’s The Odyssey, it is undying tenacity, eff ortless cunning and tempered humility that enable Odysseus to survive his perilous quest, to overcome all adversities to return to his homeland safely and regain his status as king of Ithaca. For a man destined for a decade-long venture to his homeland, patience and tenacity are truly invaluable virtues. These two traits are quintessential for the unique circumstances of Odysseus’s quest. Before Homer even reveals Odysseus’s whereabouts in Book V, Odysseus’s vengeance, purchased by his endurance, isShow MoreRelatedThe Old Man and the Sea: Analysis of Santiago841 Words   |  4 Pageswere called the Hemingway Code Heroes. Hemingway Code Heroes followed a strict code of behaviors which allowed them to live their life to the fullest. These Heroes lived simple lives without all the luxuries that others had. They concentrate on the problem at hand and do not get swayed by outside events. 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