Abstract This paper explains that the e-coli bacillus is a microbe about which much is known but has defied efforts to stamp out its unpleasant impact upon human health. The author points out that these extraordinarily tiny cells are invisible to the naked human eye and can accumulate in vast quantities in food preparation areas without individuals being aware of them. The paper relates that e-coli cells are prokaryotic and distinguished by a single, circular chromosome; such cells also contain DNA as plasmids. The author states that, in simple cases of e-coli poisoning, rehydration is essential; however, there is no evidence that antibiotics improve the course of the disease and/or expedite recovery and anti-diarrheal agents are strongly discouraged. The paper concludes that this tiny "bug" certainly seems resilient enough to cause human beings misery for some time to come.
From the Paper "The living environment and the reproductive process of the e-coli cell are also interesting. Simply put, e-coli most commonly flourish in the intestines of warm-blooded animals. In terms of reproduction, the process is simply one of binary fission, with the circular DNA chromosome replicated. The cell splits into two identical cells with each cell having the same DNA; it should be pointed out that, during the fission process, the identical chromosomal material attaches itself to different parts of the cell membrane so that "replicate" material is firmly anchored where it needs to be when the cell begins to pull apart and halve."
Abstract Sporulation has been adopted as a means of survival in the face of negative environmental conditions by a large fraction of the gram-positive bacilli. This paper examines why sporulation occurs and reviews how the process occurs in Bacillus subtilis.
From the Paper "Sporulation produces dormant endospores that can persist for thousands of years within hostile environmental conditions that would kill other forms of the bacilli. The "endospores are more resistant to extremes in temperature, dessication, solvents, ionizing radiation and detergents than quiescent fungal or other bacterial spores" (Koch, 1999). In addition, they have an endogenous metabolism rate that is 107 lower than vegetative cells (Koch, 1999)."
Abstract This study examines the importance of chromosomal location in the expression of the sporulation gene spoIIQ in Bacillus subtilis. It hypothesizes that if spoIIQ were placed in different locations of the chromosome, it would enter at different times, causing it to enter the prespore after sF activity and negating spoIIQ expression. Twelve strains of B. subtilis were transformed by an integrative plasmid so that each strain contained a lacZ gene fused to the promoter of spoIIQ, at different locations in the chromosome. This fusion was utilized to determine spoIIQ activity during sporulation conditions through simple enzyme assay. The results in the paper show differences in the levels of expression for spoIIQ-lacZ present at the various locations, suggesting that the surrounding regions are having an effect on expression. The paper concludes that these results require continued research on the determination of factors affecting spoIIQ expression.
From the Paper "The entire process of sporulation along with other functions of the bacterium is regulated using sigma factors. These sigma factors are transcription factors that bind with RNA polymerase (E) to specify which genes will be expressed based on the promoter of the gene (Stratgier 1996). Interestingly, one such sigma factor, sF, is the only sigma factor active in 1) the prespore and 2) the early stages of sporulation. As sporulation commences, a copy of the single circular bacterial chromosome is moved from the mother cell and into the developing prespore with origin entering first and the terminus last (Piggot 2000)."
Abstract This paper discusses anthrax, an acute infectious disease that came into the limelight recently due to the anthrax attacks in the United States in the weeks following the September 2001 terror attacks, causing widespread panic. The paper includes information on how the disease is caused, types of anthrax, symptoms of the disease and its treatment. The paper also presents information on the 2001 anthrax attacks in the United States and examines what makes anthrax a good bioterrorism agent.
Outline
Introduction
How is Anthrax Caused?
Bacillus Anthracis
Types of Anthrax and Ways in Which it can Infect Humans
Treatment
Anthrax as a Biological Weapon
The 2001 Anthrax Attacks
From the Paper "Anthrax is caused by the bacterium 'Bacillus anthracis' that is highly lethal in its virulent form. Anthrax most commonly occurs in wild and domestic animals, but it can also occur in humans when they are exposed to infected animals, tissue from infected animals, or high concentrations of anthrax spores. Bacillus anthracis, the bacterium which causes anthrax, is rod-shaped and about 1 by 6 micrometres in size. It was the first bacterium ever to be shown to cause disease by Robert Koch in 1877. The bacteria normally rest in spore form in the soil, and can survive for decades in this state. When ingested by a plant eating animal, the bacteria starts to multiply and eventually kills the animal. They even continue to reproduce in the carcass but eventually revert back to the dormant spore state when they run out of nutrients. ("Bacillus anthracis.")"
Abstract This paper deals with the disease anthrax and the bacterium that causes it. Included is information on history, tests, where it is found, how and who contracts it, symptoms, treatments, and uses as a biological weapon.
From the Paper "Since the events of September 11 shocked our nation we have become increasingly concerned with the possibility of further terrorist attacks. President Bush has already added a new member to his cabinet; Tom Ridge now serves as the Homeland Defense Secretary. Words such as anthrax and biological warfare, which are not usually seen unless you look for them, can now be found almost every time you turn on the television, pick up the newspaper or log-on to the internet. If you had taken a survey of Americans three months ago asking them "What is anthrax"? the most common response next to "I don"t know? would probably have been "Hey, isn"t that a rock band?? Now it can almost be considered a household word. Since September 25th several people in the United States have become infected with a disease called anthrax, some have even died, because of exposure to letters containing a white powder from an, as of yet, unknown mailer. When used as a biological weapon, anthrax posses a serious threat to people and the environment and therefore should not be used as such."
From the Paper "Bacillus thuringiensis
Insects are responsible for several devastating diseases. Certain entomopathogenic bacteria are useful as biological pesticides. The bacteria, Bacillus thuringiensis, produces a toxic proteinaceous crystal during sporulation. Upon this crystal's ingestion by an insect larvae, (-endotoxins are solubilized and activated. These toxins form a nonselective pore in the plasma membrane of the insect's midgut epithelium. Disruption of the membrane's transepithelial potential ultimately causes the insect's death. At present, various B. thuringiensis formulations are commercially available.
Insects such as mosquitoes and black flies transmit some of the world's most deadly diseases. Through the transmission of pathogenic microorganisms between humans and animals, these..."
Abstract This paper examines the dangers of the notorious chemical DDT and shows why it should be banned by the year 2007, as environmentalist groups have aimed to do. The paper covers issues relating to the chemical including a growing resistance to its use, effective alternatives and the extent of its environmental destruction.
From the Paper "The environmental damage that DDT causes is enough in itself to justify a total ban. DDT is a very persistent chemical and because if its molecular structure breaks down very slowly within nature. There are rough estimates that the half-life of DDT is around 12-15 years depending on the climate it is exposed to. This is partly why it is so dangerous in the environment. Another factor is that DDT is able to travel great distances, and is found every where throughout the globe. This is a strange and disturbing discovery because some places have never been sprayed before, such as Antarctica and the ocean bottoms. The spraying of DDT has unintentionally killed some main predators of the mosquito. Dragonfly larva hunt mosquito larva in puddles and stagnant ponds and also the adult dragonfly will hunt adult mosquitoes further reducing their numbers. DDT has worked in the past but as it destroyed fragile ecosystems it has now increased mosquito numbers. DDT is also the linked chemical responsible for the decline in the population of the Bald eagle and the Peregrine falcon. These two species are at the top of the food chain, thus their prey usually have been exposed to DDT."
Abstract This paper offers an explanation of the Anthrax disease. The paper begins by defining Anthrax as an acute disease that is caused by a bacteria known as bacillus anthracis. The paper then explains the various methods of contracting Anthrax which include cutaneous through the skin, inhalation and gastrointestinal through food or digesting the bacteria. The paper includes a number of references to reports on the issue by the center for disease control and the FBI. The paper makes reference to the recent Anthrax scares in the U.S., where a white powdery substance was sent via postal mail across the country.
From the Paper "The cutaneous form of anthrax occurs as an infection of the skin. This type of anthrax is caused by touching animals or animal products with an anthrax infection. The cutaneous form of anthrax is the least serious form of anthrax. The inhaled version of anthrax occurs when a person inhales anthrax spores that are present in infected animal products or in soil that has been exposed to infected animals. The inhaled version of anthrax is the most serious form of the disease. The gastrointestinal version of anthrax occurs by eating undercooked meat from animals with anthrax. This is the rarest form of anthrax that people can contract."
Abstract This paper looks at leprosy (or Hansen's disease) which, until the AIDS epidemic was the most feared infectious disease. It traces its history from Biblical times to the discovery of its cause in 1873 by Dr. Gerhard Henrik Armauer Hansen, the bacillus Mycobacterium leprae. It examines various aspects of the disease, including resistance to drugs, statistics and symptoms. The paper is illustrated with drawings and diagrams.
From the Paper "Up until the 20th century, the treatment for leprosy was the dispensation of oil extracted from the nuts from the Hydnocarpus tree through mouth, injection or ointment. However, the first breakthrough with regards to a cure came in the 1940's with the development of dapsone. Dapsone was used to arrest the disease and was a treatment that took many years, possibly a lifetime until the 1960's when, through mal-treatment, the mycobacterium developed a resistance to the only known leprosy cure. Then, in the late 1960?s, rifampicin and clofazimine were discovered, and when combined with dapsone in 1981, the leprosy patients finally received their long awaited cure called Multi-Drug-Treatment or MDT."
Abstract This paper discusses the threat posed by anthrax as a biological weapon. The paper describes the use and manufacturing of anthrax as a biological weapon. The paper examines the physical properties of anthrax and describes the effects it has on human beings and animals. The available treatment for an anthrax infection is presented in the paper.
From the Paper "The scientific name of anthrax, bacillus anthracis, is derived from anthrakis, the Greek word for coal. The reason for this is that the disease caused by the substance is associated with black, lesions that look like coal in some cases. The cellular appearance of anthrax can be identified with fair certainty by experienced microbiologists. The problem is however that few of these professionals not working in the veterinary community have had the opportunity to either work with or see the cellular or colonial appearance of anthrax. This makes it difficult to identify and prevent the effects of the weapon in practice."
Abstract This paper examines how the discovery of germs and more particularly Robert Koch's discovery of the tubercle bacillus and consequent germ theory changed the way in which the world viewed the white plague and its victims. It also looks at how the discovery of the germ theory and the tuberculosis prevention education campaign that evolved, changed the private and public lives of both the people living with tuberculosis and the lives of those around them.
From the Paper "With the isolation of tuberculin proving useless in the synthesis of any kind of vaccine or treatment, it remained imperative to avoid contracting the disease in any way possible. The Germ Theory explains the transmission of disease by way of microbes or bacilli that travel through the air on a person's breath or in bodily fluids, the most dangerous of which was saliva, with the common practice of spitting in the streets proving just as dangerous as kissing. The public were advised to avoid physical contact with any person infected with the tubercle bacillus, they were not to shake his hand, and mothers must take particular care not to let them kiss their children lest he infect them with the deadly consumption. "
Abstract Anthrax, which is caused by a spore-forming bacterium called Bacillus anthracis, actually occurs as an acute and infectious disease, and is generally found in animals, both wild and domestic. This paper examines how the disease spreads, its different forms, its symptoms and its prevention. In particular, it looks at how it is used as part of bioterrorism.
From the Paper "Anthrax is termed a zoonotic disease (meaning that it is acquired by people from animals) (Brachman & Friedlander, 1994). The earliest accounts of humans getting this disease are thought to be caused by anthrax dating from the Fifth Egyptian Plague, which was 3500 years ago (Brachman & Friedlander, 1994). During the Middle Ages, anthrax, which was then called "The Black Bane," actually killed very large numbers of people and animals over in Europe. At that time, there was no understanding of the disease, and there was no vaccine (Brachman & Friedlander, 1994). Much like the bubonic plague, people simply did not seem to understand how the disease worked or how they should prevent it."
Abstract The paper relates that the Black Death of the Middle Ages was the bubonic plague, a form of plague that is spread by rats. The paper describes the virulence of the plague that was seen as an evil force over which human beings had no control. The paper examines the mechanism of the disease. The paper reveals that the plague is not only a disease of the past; there is concern that the bubonic plague could be employed as a weapon by a rogue state or a terrorist organization.
From the Paper "The organism that causes bubonic plague is well known today. The plague is caused by a bacillus called Yersinia pestis that is transmitted by the flea. The plague is primarily a disease of rodents, and epidemics with human begins begin with contact with the fleas of infected rodents. The two primary forms of the disease in the human being are the bubonic plague, the most common form in the Middle Ages, and which is characterized by the swelling of the lymph nodes, and pneumonic plague, with the extensive involvement of the lungs. The plague is spread from rodents to human beings in crowded urban areas. In the fourteenth century, the disease was known as the Black Death, and some plague infections were bubonic and some were pneumonic."
Abstract This paper discusses the impact of the Black Death (bubonic plague) in the Middle East and North Africa. It begins by giving a brief overview of the plague, its symptoms and how it spread. In particular, the paper focuses on the social and economic effects of the plague and emphasizes the plague's effects on North Africa and the Middle East in the 13th Century.
From the Paper "The Black Death, also known as the plague, was, in effect, what we now call an epidemic. The plague was considered a pandemic because it covered such a wide area. The plague is an infectious fever caused by a bacillus with the scientific name Bacillus Pasteurella. High fevers, chills and then dilirium characterize the bubonic plague. The lymph nodes swell and become painful. The swellings are called buboes, hence the name bubonic plague. Death from this form usually came in about a week. Wild rodents carried the disease, the black rat in particular, and later the larger and stronger relative, known as the brown, or Norway rat. A connection is mentioned between the rats and the plague in the Hindu Holy Book, Bhagavata Purana."
