Medical Microbiology, Chapter 1

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Medical Microbiology, Chapter 1
2013-01-29 09:48:49
Brief History Microbiology

microbes, microbiologists
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  1. Why do plants depend on MO?
    To help them obtain the nitrogen they need for survival.
  2. Why do animals such as cows and sheep need MO?
    To digest the cellulose in their plant-based diets.
  3. Why does our ecosystem rely on MO?
    To enrich soil, degrade wastes, and support life.
  4. How do "we" use MO?
    To make wine and cheese, develop vaccines and antibiotics, etc.
  5. Why are MO essential part of our lives?
    They are part of us and many keep us healthy.
  6. Do MO cause disease?
    Some do from the common cold to more serious diseases.
  7. What Greek physician wondered whether there is a link between enviornment and disease?
    Hippocrates (460-370 B.C.)
  8. What Greek historian questioned why he and other survivors of the plague could have intimate contact with the victims and not fall ill again?
    Thucydides (460-404 B.C)
  9. What Dutch tailor, merchant, and lens grinder first discovered the bacterial world?
    Antoni van Leeuwenhoek (1632-1723)
  10. Leeuwenhoek's "beasties" as he sometimes dubbed them, were called MO or as we know them today as microbes? What are MO?
    All organisms too small to be seen without a microscope.
  11. What Swedish botanist developed the taxonomic system?
    Carolus Linnaeus (1707-1778)
  12. What is the taxonomic system?
    A system for naming plants and animals and grouping similar organisms together.
  13. What are the six basic categories of MO?
    • 1. Fungi
    • 2. Protozoa
    • 3. Algae
    • 4. Bacteria
    • 5. Archaea
    • 6. Small multicellular animals
  14. What microbes are too small to be seen with a light microscope?
    Viruses, they are much smaller than the smallest prokaryote.
  15. What microbes remained hidden to Leeuwenhoek and other early microbiologists?
  16. Fungi cells are...
  17. What is a eukaryotic cell?
    A cell that contains a nucleus composed of genetic material surrounded by a distinct membrane.
  18. How are fungi different from plants?
    Because they obtain their food from other organisms (rather than making it for themselves).
  19. How do fungi differ from animals?
    By having cell walls.
  20. Are viruses MO?
    No, because they neither replicate themselves nor carry on the chemical reactions of living things.
  21. Fungi include...
    Molds and yeasts.
  22. Molds are...
    Typically multicellular that grow as long filamentous hyphae, which intertwine to make up the body of the mold.
  23. Molds reproduce by...
    Sexual and axesual spores.
  24. What are some examples of molds?
    The cottony growths on cheese, bread, and jams.
  25. What is Penicillium chrysogenum?
    A mold that produces penicillin.
  26. Yeasts are...
    Unicellular and typically oval to round.
  27. Yeasts reproduce...
    Asexually by budding, a process in which a daughter cell grows off the mother cell.

    Some yeast also produce sexual spores.
  28. What is Saccharomyces cerevisiae?
    A yeast that causes bread to rise and produces alcohol from sugar.
  29. What is Candida albicans?
    A yeast that causes most cases of yeast infections in women.
  30. What is the significance fungi have in the world?
    They are significant to the environment, food production, and are agents of human disease.
  31. Protozoa cells are...
    Single-celled eukaryotes.
  32. How are protozoa similar to animals?
    Because of their nutritional and cellular structure.
  33. What does protozoa mean in Greek?
    "First animals"
  34. Most protozoa are capable of...
  35. How do scientists categorize protozoa?
    In accordance to their locomotive structures.
  36. What are protozoa's locomotive structures?
    Cilia, Flagella, and Pseudopodia.
  37. What are pseudopodia?
    Extensions of a cell that flow in the direction of travel.
  38. What are cilia?
    Numerous, short protrusions of a cell that beat rhythmically to propel the protozoan through its enviornment.
  39. What are flagellum?
    Extentions of a cell, but are fewer, longer, and more whiplike than cilia.
  40. What is the protozoa Plasmodium?
    The malaria-causing protozoa that are non-motile in their mature forms.
  41. Where do protozoa live?
    Typically freely in water, but some live inside animal hosts, where they can cause disease.
  42. Protozoa reproduce...
    Most asexually, though some are sexual as well.
  43. Algae cells are...
    Unicellular or multicellular photosynthetic organisms.
  44. What does photosynthetic mean?
    Organisms that make their own food from carbon dioxide and water using energy from sunlight.
  45. How does algae differ from plants?
    From their relative simple reproductive structures.
  46. How are algae and plants similar?
    They are both photosynthetic.
  47. How are algae categorized?
    On the basis of their pigmentation and the composition of their cell walls.
  48. What are some large algae?
    Seeweeds and kelps.
  49. What MO are used for their gelatinous cell walls as thickeners and emulsifiers in many food and cosmetic products, as well as in microbiological laboratory media?
  50. Where are unicellular algae commonly found?
    In freshwater ponds, streams, and lakes, and in the oceans as well.
  51. What are the major food of small aquatic and marine animals and provide most of the world's oxygen as a by-product of photosynthesis?
  52. What MO has glasslike cell walls of diatoms that provide a grit for many polishing compounds?
  53. Bacteria and archaea cells are...
  54. What is a prokaryotic cell?
    Any unicellular MO that lacks a nucleus.
  55. What polysaccharide are bacterial cell walls composed of?
    Peptidoglycan, though some bacteria lack cell walls.
  56. Do archaea cell walls have peptidoglycan?
    No, they are instead composed of other polymers.
  57. Bacteria and archaea reproduce...
  58. Most archaea and bacteria cells are smaller than eukaryotic cells. How do they live?
    They live singly or in pairs, chains, or clusters in almost every habitat containing sufficient moisture.
  59. Archaea live in...
    Extreme enviornments.
  60. Are archaea known to cause disease?
  61. How is bacteria beneficial to us?
    Dead plants and animals are degraded by bacteria (and fungi) to release phosphorus, sulfur, nitrogen, and carbon back into the air, soil, and water to be used by new generations of organisms.
  62. How large are parasitic worms?
    From microscopic to over 7 meters (approximately 23 feet) in length.
  63. When were the first viruses discovered?
    1932, when the electron microscope was invented.
  64. All viruses are...
    Acellular (not composed of cells) obligatory parasites composed of small amounts of genetic material (either DNA or RNA) surrounded by a protein coat.
  65. When did Leeuwenhoek first report the exsistence of most types of MO?
    The late 1600's, but microbiology did not develop significantly as a field of study for almost two centuries.
  66. What were reasons why microbiology did not develop quickly?
    Leeuwenhoek was a suspicious and secretive man. No apprentice was ever trained and he never sold or let anyone peek through his little instruments (the very first microscope, a little more than a magnifying glass). It took almost 100 years for scientists to make microscopes of equivalent quality.

    Scientists in the 1700s considered microbes to be curiosities of nature and insignificant to human affairs. In the late 1800s, scientists then bagan to adopt a new philosophy, one that demanded experimental proof rather than mere acceptance of traditional knowledge.
  67. What was the "Golden Age of Microbiology"?
    When scientists and the blossoming field of microbiology were driven by the search for answers to the following four questions:

    • 1. Is spontaneous generation of microbial life possible?
    • 2. What causes fermentation?
    • 3. What causes disease?
    • 4. How can we prevent infection and disease?
  68. Many philosophers and scientists of past ages thgouht that living things arose via three processes:
    • 1. Through asexual reproduction.
    • 2. Through sexual reproduction.
    • 3. From nonliving matter (abiogenesis or spontaneous generation).
  69. Who was responsible for the theory of spontaneous generation?
    Aristotle (384-322 B.C.), it was widely accepted for over 2000 years because it seemed to explain a variety of commonly observed phenomena.
  70. What Italian physican conducted experiments where when decaying meat was kept isolated from flies, maggots never developed, and when the meat was exposed to flies, they were soon infested? 
    Francesco Redi (1626-1697), results of his experiments had scientists beginning to doubt Aristotle's theory and adopt the view that animals only come from other animals.
  71. What British investigator favored the theory of spontaneous generation?
    John T. Needham (1713-1781)
  72. What experiments did Needham conduct?
    Needham boiled beef gravy and infusions of plant materials in vials, then tightly sealed them with corks.
  73. What happened with Needham's experiment of the beef gravy and infusions?
    Days later, he observed the vials were cloudy and examination revealed an abundance of "microscopical animals of most dimensions". 

    Needham stated there must be a "life force" that causes inanimate matter to spontaneously come to life, since he had heated the vials sufficiently to kill everything.
  74. Which Italian scientist reported results that contradicted Needham's findings?
    Lazzaro Spallanzani (1729-1799)

    • He concluded three things:
    • 1. Needham either failed to heat vials sufficiently to kill all microbes, or had not sealed them tightly enough.
    • 2. MO exist in air and can contaminate experiments.
    • 3. Spontaneous generation of MO does not occur, all living things arise from other living things.
  75. What experiments did Spallanzani conduct?
    In 1799, he boiled infusions for almost an hour and sealed the vials by melting their slending necks closed. His infusions remained clear unless he broke the seal exposing them to air.
  76. Why was it difficult to dethrone the theory of spontaneous generation that had held sway for over 2000 years?
    Aristotle was a very notable man and many backed his theory. 

    • 1. His sealed vials did not allow enough air for organisms to thrive.
    • 2. His prolonged heating destroyed the "life force".
  77. What French chemist conducted experiments that finally laid the theory of spontanous generation to rest?
    Louis Pasteur (1822-1895) "Work, Will, Success, fill human existence."
  78. How did Pasteur's experiments differ from Spallanzani's?
    He boiled infusions long enough to kill everything like Spallanzani's experiments, but instead of sealed flasks, he bent their necks into an S-shape "swan-necked flasks", which allowed air to enter preventing the introduction of dust and microbes into the broth.
  79. What were the results of Pasteur's hypothesis on spontaneous generation?
    In 1861, he reported that his "swan-necked flasks" remained free of microbes even 18 months later. Since they all contained nutrients (including air) known to be required by living things, he concluded "Never will spontaneous generation recover from the mortal blow of this simple experiment".
  80. What is the scientific method?
    Questions that are answered through observations of the outcomes of carefully controlled experiments, instead of by conjecture or according to the opinions of any authority figure.
  81. What are the four basic steps of the scientific method?
    • 1. A group of observations leads a scientist to ask a question about some phenomenon.
    • 2. The scientist generates a hypothesis - that is, a potential answer to the question.
    • 3. The scientist designs and conducts an experiment to test the hypothesis.
    • 4. Based on the observed results of the experiment, the scientist either accepts, rejects, or modifies the hypothesis.
  82. Theories or Laws
    Accepted hypotheses that explain many observations and are repeatedly verified by numerous scientists over many years.
  83. What causes fermentation?
  84. What is fermentation?
    Not only the formation of alcohol from sugar, but also other chemical reactions such as the formation of lactic acid, putrefaction of meat, and the decomposition of waste.
  85. What did Pasteur discover when conducting his "grape juice" experiments with yeast cells?
    • That yeasts are facultative anaerobes (organisms that can live with or without oxygen).
    • Bacteria cells: ferment grape juice to produce acids. Yeast cells: ferment grape juice to produce alcohol.
  86. What did Pasteur develop when he discovered that anaerobic bacteria fermented grape juices into acids?
    He developed a method for preventing the spoilage of wine. Pasteurization: a process of heating the grape juice just enough to kill most contaminating bacteria without changing the juice's basic qualities, so that it could be inoculated with yeast to ensure that alcohol fermentation occurred.
  87. Who began the field of industrial microbiology or biotechnology?
    Louis Pasteur (1822-1895)
  88. What German scientist resurrected the chemical explanation by showing that fermentation does not require living cells?
    • Eduard Buchner (1860-1917)
    • In 1897, his experiments demonstrated the presence of enzymes, which are cell-produced proteins that promote chemical reactions.
  89. Who began the study of biochemistry and metabolism?
    Eduard Buchner (1860-1917)
  90. What is metabolism?
    A term that refers to the sum of all chemical reactions within an organism.
  91. What Italian philosopher conjectured as early as 1546 that "germs of contagion" cause disease?
    Girolamo Fracastoro (1478-1553), the idea that germs might be invisible living organisms awaited Leeuwenhoek's investigations 130 years later.
  92. What led the Pasteur's hypothesis in 1857 that MO are also responsible for diseases?
    The discovery that bacteria are responsible for spoiling wine. This idea came to be known as the germ theory of disease.
  93. What diseases does the germ theory apply to?
    Only infectious diseases.
  94. Germ Theory of Disease
    A particular infectious disease is typically accompanied by the same symptoms in all affected individuals and each are caused by a specifiic germ, called a pathogen.
  95. Who was the cheif investigator in disproving spontaneous generation and determining the cause of fermentation?
    Louis Pasteur (1822-1895)
  96. What is etiology?
    The study of causation of disease.
  97. Who began the study of etiology?
    Robert Koch (1843-1910), a German doctor who began a race with Pasteur to discover the cause of anthrax.
  98. Who discovered the cause of anthrax?
    Robert Koch (1843-1910)
  99. How did Koch discover anthrax?
    He examined the blood of infected animals, and in every case he identified a rod-shaped bacterium that formed chains. He observed the formation of resting stages (endospores) within the bacterial cells and showed that the endospores always produced anthrax when they were injected into mice.
  100. Who was the first to find that a bacterium was proven to cause a disease?
    Robert Koch (1843-1910)
  101. Which scientist hypothesized that a bacterial colony arises from a single bacterial cell?
    Robert Koch (1843-1910), he inoculated samples from each colony into laboratory animals to see which caused disease.
  102. Who is responsible for the method of isolation as a standard technique in microbiological and medical labs to this day, though a gel called agar, derived from red seaweed, is used instead of gelatin or potato.
    Robert Koch (1843-1910)
  103. Koch is responsible for many other advances in laboratory microbiology, including the following...
    • Simple staining techniques for bacterial cells and flagella. (1877)
    • First photomicrograph of bacteria.
    • First photograph of bacteria in diseased tissue.
    • Techniques for estimating number of bacteria in a solution based on number of colonies that form after inoculation onto a solid surface.
    • Use of steam to sterilize growth media.
    • Use of Petri dishes to hold solid growth media.
    • Lab techniques such as transferring bacteria between media using a platinum wire that had been heat-sterilized in a flame.
    • Elucidation of bacteria as distinct species.
  104. Petri dishes
    Named for Richard Petri, Koch's assistant, who invested them in 1887.
  105. Mycobacterium tuberculosis
    A rod-shaped bacterium that causes tuberculosis.
  106. Koch's postulates
    A series of steps that must be taken to prove the cause of any infectious diseases. One of the more important contributions to microbiology.
  107. Steps of Koch's postulates
    • 1. The suspected causative agent must be found in every case of the disease and be absent from healthy hosts.
    • 2. The agent must be isolated and grown outside the host.
    • 3. When the agent is introduced to a healthy, susceptible host, the host must get the disease.
    • 4. The same agent must be found in the diseased experimental host.
  108. Dmitri Ivanowski (1864-1920) and Martinus Beijerinck (1851-1931) discovered...
    A certain disease in tobacco plants is caused by a pathogen that passes through filters with such extremely small pores that bacteria cannot pass through, recognizing this pathogen as a filterable virus or just virus now.
  109. What American physician proved in 1900 that viruses can cause such diseases as yellow fever in humans?
    Walter Reed (1851-1902)
  110. Why did scientists begin to use dyes to stain specimens?
    Because most microbes are colorless and difficult to see under the microscope.
  111. Which Danish scientist developed a more important staining technique in 1884 than Koch's simple staining technique?
    Hans Christian Gram (1853-1938)
  112. Gram Stain
    A procedure, which involves the application of a series of dyes, leaves some microbes purple and the others pink. Gram positive is purple, gram negative is pink.
  113. Nosocomial infections
    Infections acquired in the health care setting.
  114. What four health care practitioners were especially instrumental in changing the way health care is delivered?
    Semmelweis, Lister, Nightingale, and Snow
  115. What physician was responsible for the drop in mortality rate of women giving birth?
    Ignaz Semmelweis (1818-1865), he hypothesized that medical students carried "cadaver particles" from their autopsy studies into the delivery rooms, and that these "particles" resulted in puerperal fever.
  116. What bacterium is the primary cause of puerperal fever?
    Streptococcus, it is usually harmless on skin or in mouth, but causes severe complications when it enters the blood.
  117. What English physician modified and advanced the idea of antisepsis in health care settings?
    Joseph Lister (1827-1912), he began spraying wounds, surgical incisions, and dressings with carbolic acid (phenol), a chemical that had previously proven effective in reducing odor and decay in sewage.
  118. Who became the founder of antiseptic surgery and opened new fields of research into antisepsis and disinfection?
    Joseph Lister (1827-1912), he vindicated Semmelweis.
  119. What English nurse succeeded in introducing cleanliness and other antiseptic techniques into nursing practice?
    Florence Nightingale (1820-1910)
  120. Who is the founder of modern nursing?
    Florence Nightingale (1820-1910)
  121. What English physician played a key role in setting standards for good public hygiene to prevent the spread of infectious diseases?
    John Snow (1813-1858), his careful documentation of the cholera epidemic highlightened the critical need for adequate sewage treatment and pure water supply.
  122. What two branches of microbiology did John Snow set a foundation for?
    Infection Control and Epidemiology, which is the study of the occurrence, distribution, and spread of disease in humans.
  123. What English physician tested the hypothesis that a mild disease called cowpox provided protection against potentially fatal smallpox?
    Edward Jenner (1749-1823)
  124. What field of study did Jenner play a role in establishing?
    Immunology, the study of the body's specific defenses against pathogens.
  125. Vaccination
    Jenner named vaccination after Vaccinia virus, that causes cowpox.
  126. Vaccine
    Pastuer capitalized on Jenner's work by producing weakened strains of various pathogens for use in preventing the serious diseases they cause. He used the term vaccine to refer to all weakened, protective strains of pathogens and subsequently developed successful vaccines against fowl cholera, anthrax, and rabies.
  127. "Magic Bullets"
    Germain microbiologist Paul Ehrlich (1854-1915) suggested that since Gram's discovery that stained bacteria could be differentiated into two types, that chemicals could be used to kill MO differently. He wanted to find a "magic bullet" that would destroy pathogens while remaining nontoxic to humans.
  128. What "magic bullets" did Erlich discover?
    By 1908, he had discovered chemicals active against the protozoan parasites that cause sleeping sicknesses and against the causative agent of syphilis.
  129. What branch of medical microbiology did Ehrlich's discoveries begin?
  130. What are the four major questions that drive microbiological investigations today in the Modern Age of Microbiology?
    • 1. What are the basic chemical reactions of life?
    • 2. How do genes work?
    • 3. What role do MO play in the enviornment?
    • 4. How do we defend against disease?
  131. Biochemistry
    The study of metabolism-that is, the chemical reactions that occur in living organisms.
  132. How did biochemistry begin?
    With Pasteur's work on fermentation by yeast and bacteria, and with Buchner's discovery of enzymes in yeast extract.
  133. What did microbiologists, Albert Kluyver (1888-1956) and his student C.B. van Niel (1897-1985) propose?
    That basic biochemical reactions are shared by all living things, that these reactions are relatively few in number, and that their primary feature is the transfer of electrons and hydrogen ions.
  134. What are some basic biochemical research practical applications?
    The design of herbicides and pesticides; diagnosis of illnesses and monitoring of patient's responses to treatment; treatment of metabolic diseases; and the design of drugs to treat diseases.
  135. Genetics
    The scientific study of inheritance. They manipulate genes in microbes, plants, and animals for practical applications.
  136. Who determined that genes are contained in molecules of DNA while working with the bacterium Streptococcus pneumoniae?
    • Oswald Avery (1877-1955)
    • Colin MacLeod (1909-1972)
    • Maclyn McCarty (1911-2005)
  137. Who established that a gene's activity is related to the function of the specifiv protein coded by that gene while working with the bread mold Neurospora crassa in 1958?
    • George Beadle (1903-1989)
    • Edward Tatum (1909-1975)
  138. What new disciplines developed during the advances of microbial genetics over the past 40 years?
    • Molecular Biology
    • Recombinant DNA technology
    • Gene Therapy
  139. Molecular Biology
    Combines aspects of biochemistry, cell biology, and genetics to explain cell function at the molecular level. Molecular biologists are particularly concerned with genome sequencing.
  140. Genome
    The total genetic information of an organism.
  141. What are the goals of molecular microbiologists today?
    To get a fuller understanding of the genomes of organisms that will result in practical ways to limit disease, repair genetic defects, and enhance agricultural yield.
  142. What Americal Nobel laureate proposed in 1965 that gene sequences could provide a means of understanding evolutionary relationships and processes, establishing taxonomic categories that more closely reflect these relationships, and indentifying the existence of microbes that have never been cultured in a laboratory?
    Linus Pauling (1901-1994)
  143. Who discovered in the 1970's that significant differences in nucleic acid sequences among organisms clearly reveal that cells belong to one of three major groups-bacteria, archaea, or eukaryotes-and not merely two groups (prokaryotes and eukaryotes) as previously thought?
    Carl Woese (1928- )
  144. Recombinant DNA technology
    Molecular biology is applied in recombinant DNA technology, and is commonly called genetic engineering, which was first developed using microbial models.
  145. Gene Therapy
    The use of recombinant DNA technology to start a process that involves inserting a missing gene or repairing a defective one in human cells. (when researchers insert a desired gene into host cells, where it is incorporated into a chromosome and begins to function normally)
  146. Bioremediation
    The use of living bacteria, fungi, and algae to detoxify polluted enviornments.
  147. Who discovered a bacteria capable of converting nitrogen gas (N2) from the air into nitrate (NO3), the form of nitrogen used by plants?
    Martinus Beijerinck (1851-1931)
  148. What essential role do microbial communities play in the enviornment?
    They play a role in the decay of dead organisms and the recycling of checmicals such as carbon, nitrogen, and sulfur.
  149. What Russian microbiologist elucidated the role of MO in the recycling of sulfur?
    Sergei Winogradsky (1856-1953)
  150. What two microbiologists developed laboratory techniques for isolating and growing enviornmentally important microbes?
    Beijerinck and Winogradsy
  151. How can we limit the microbes in the enviornment that play in the causation of disease?
    We can take steps to limit their abundance and control their spread in the enviornment, such as sewage treatments, water purification, disinfection, pasteurization, and sterilization.
  152. What scientists played a role into developing fields of serology and immunology?
    German bacteriologist Emil von Behring (1854-1917) and Japanese microbiologist Shibasabura Kitasato (1852-1931) that worked in Koch's laboratory.
  153. What dis Behring and Kitasato report in their findings?
    That there is an existence in the blood of chemicals and cells that fight infection, which developed into the study of serology (the study of blood serum) and that the checmicals in the liquid portion of blood can fight disease, which developed into the study of immunology (the study of the body's defense against specific pathogens).
  154. Who discovered penicillin in 1929?
    Alexander Fleming (1881-1955)
  155. Who discovered sulfa drugs in 1935?
    Gerhard Domagk (1895-1964)
  156. What will microbiologist discover in the next 50 years?
    • There are many questions such as:
    • 1.What is it about the physiology of life forms known only by their nucleic acid sequences that prevents those life forms from being grown in the laboratory?
    • 2. Can bacteria and archaea be used in ultraminiature technologies such as living computer circuit boards?
    • 3. How can an understanding of microbial communities help us understand the positive aspects of microbial action in preventing and curing diseases, recycling nutrients, degrading pollutants, and moderating climiate changes?
    • 4. What genetic sequences make some microbes pathogenic and what can we do at a genetic level to defend against these pathogens?
    • 5. How can we reduce the threat from microbes resistant to antimicrobial drugs as well as conquer emerging and reemerging infectious diseases?
  157. Zone of Inhibition
    The clear area surrounding a MO colony, which is producing the antibiotic and preventing growth of the specific MO.