Microbiology

Microbiology

1) What problem are associated with the use of live attenuated vaccines?

2) Many of the serological tests require a supply of antibodies against pathogens. For example, to test for Salmonella, anti-Salmonella antibodies are mixed with the unknown bacterium. How these antibodies obtained?

3) A test for antibodies against Treponema pallidum uses the antigen cardiolipin and patient’s serum (Suspected of having antibodies). Why do the antibodies react with cardiolipin? What is the disease?  Microbiology

Clinical Application Question 1-4 for Chapter 19 on page 557

1) Fungal infections such as athlete’s foot are chronic. These fungi degrade skin Keratin but are not invasive and do not produce toxins. Why do you suppose that many of the symptoms of a fungal infection are due to hypersensitivity to the fungus?

2) After working in a mushroom farm for several months, a worker develops these hives, edema, and swelling lymph node Microbiology

a) What do these symptoms indicate?

b) What mediators cause these symptoms?

c) How many sensitivities to a particular antigen be determined?

d) Other employees do not appear to have any immunological reactions. What could explain this?

(Hint: The allergen is conidiophores from molds growing in the mushroom farm)

3) Physicians administering live, attenuated mumps and measles vaccines prepared in chick embryos are instructed to have epinephrine available. Epinephrine will not treat these viral infections. What is the purpose of keeping this drug on hand? Microbiology

4) A woman with blood type A+ once received a transfusion of AB+ blood. When she carried a type B+ fetus, the developed hemolytic disease of the newborn. Explain why this fetus developed this condition even though another type B+ fetus in a different type A+ mother was normal

Micro-organisms and their activities are vitally important to virtually all processes on Earth. Micro-organisms matter because they affect every aspect of our lives – they are in us, on us and around us.

Microbiology is the study of all living organisms that are too small to be visible with the naked eye. This includes bacteria, archaea, viruses, fungi, prions, protozoa and algae, collectively known as ‘microbes’. These microbes play key roles in nutrient cycling, biodegradation/biodeterioration, climate change, food spoilage, the cause and control of disease, and biotechnology. Thanks to their versatility, microbes can be put to work in many ways: making life-saving drugs, the manufacture of biofuels, cleaning up pollution, and producing/processing food and drink. Microbiology

Microbiologists study microbes, and some of the most important discoveries that have underpinned modern society have resulted from the research of famous microbiologists, such as Jenner and his vaccine against smallpox, Fleming and the discovery of penicillin, Marshall and the identification of the link between Helicobacter pylori infection and stomach ulcers, and zur Hausen, who identified the link between papilloma virus and cervical cancer. Microbiology

Microbiology research has been, and continues to be, central to meeting many of the current global aspirations and challenges, such as maintaining food, water and energy security for a healthy population on a habitable earth. Microbiology research will also help to answer big questions such as ‘how diverse is life on Earth?’, and ‘does life exist elsewhere in the Universe’?

 

Microbiology essentially began with the development of the microscope. Although others may have seen microbes before him, it was Antonie van Leeuwenhoek, a Dutch draper whose hobby was lens grinding and making microscopes, who was the first to provide proper documentation of his observations. His descriptions and drawings included protozoans from the guts of animals and bacteria from teeth scrapings. His records were excellent because he produced magnifying lenses of exceptional quality. Leeuwenhoek conveyed his findings in a series of letters to the British Royal Society during the mid-1670s. Although his observations stimulated much interest, no one made a serious attempt either to repeat or to extend them. Leeuwenhoek’s “animalcules,” as he called them, thus remained mere oddities of nature to the scientists of his day, and enthusiasm for the study of microbes grew slowly. It was only later, during the 18th-century revival of a long-standing controversy about whether life could develop out of nonliving material, that the significance of microorganisms in the scheme of nature and in the health and welfare of humans became evident. Microbiology

Spontaneous generation versus biotic generation of life

The early Greeks believed that living things could originate from nonliving matter (abiogenesis) and that the goddess Gea could create life from stones. Aristotle discarded this notion, but he still held that animals could arise spontaneously from dissimilar organisms or from soil. His influence regarding this concept of spontaneous generation was still felt as late as the 17th century, but toward the end of that century a chain of observations, experiments, and arguments began that eventually refuted the idea. This advance in understanding was hard fought, involving series of events, with forces of personality and individual will often obscuring the facts. Microbiology

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Although Francesco Redi, an Italian physician, disproved in 1668 that higher forms of life could originate spontaneously, proponents of the concept claimed that microbes were different and did indeed arise in this way. Such illustrious names as John Needham and Lazzaro Spallanzani were adversaries in this debate during the mid-1700s. In the early half of the 1800s, Franz Schulze and Theodor Schwann were major figures in the attempt to disprove theories of abiogenesis until Louis Pasteur finally announced the results of his conclusive experiments in 1864. In a series of masterful experiments, Pasteur proved that only preexisting microbes could give rise to other microbes (biogenesis). Modern and accurate knowledge of the forms of bacteria can be attributed to German botanist Ferdinand Cohn, whose chief results were published between 1853 and 1892. Cohn’s classification of bacteria, published in 1872 and extended in 1875, dominated the study of these organisms thereafter. Microbiology

Microbes and disease

Girolamo Fracastoro, an Italian scholar, advanced the notion as early as the mid-1500s that contagion is an infection that passes from one thing to another. A description of precisely what is passed along eluded discovery until the late 1800s, when the work of many scientists, Pasteur foremost among them, determined the role of bacteria in fermentation and disease. Robert Koch, a German physician, defined the procedure (Koch’s postulates) for proving that a specific organism causes a specific disease. Microbiology

The foundation of microbiology was securely laid during the period from about 1880 to 1900. Students of Pasteur, Koch, and others discovered in rapid succession a host of bacteria capable of causing specific diseases (pathogens). They also elaborated an extensive arsenal of techniques and laboratory procedures for revealing the ubiquity, diversity, and abilities of microbes.

Progress in the 20th century

All of these developments occurred in Europe. Not until the early 1900s did microbiology become established in America. Many microbiologists who worked in America at this time had studied either under Koch or at the Pasteur Institute in Paris. Once established in America, microbiology flourished, especially with regard to such related disciplines as biochemistry and genetics. In 1923 American bacteriologist David Bergey established that science’s primary reference, updated editions of which continue to be used today. Microbiology

Since the 1940s microbiology has experienced an extremely productive period during which many disease-causing microbes have been identified and methods to control them developed. Microorganisms have also been effectively utilized in industry; their activities have been channeled to the extent that valuable products are now both vital and commonplace.

The study of microorganisms has also advanced the knowledge of all living things. Microbes are easy to work with and thus provide a simple vehicle for studying the complex processes of life; as such they have become a powerful tool for studies in genetics and metabolism at the molecular level. This intensive probing into the functions of microbes has resulted in numerous and often unexpected dividends. Knowledge of the basic metabolism and nutritional requirements of a pathogen, for example, often leads to a means of controlling disease or infection Microbiology

 

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