mbp

• Microbiology


  The study of organisms and agents too small to be seen clearly by the unaided eye—that is, the study of microorganisms
• K.Lloyd: '"This is one of the biggest biomes on the planet."'
• What do microbes do?

  • Perform a huge range of functions – benign or beneficial roles
  • A 2011 study found that people with a high diversity of microbes on their skin were less attractive to mosquitoes
  • Discovery of Penicillin Antibiotics (Alexander Fleming)
  • Break down some substances in food that cannot be digested
  • Production of milk and dairy products
• STAPHYLOCOCCUS AUREUS (MRSA)


  • First documented: 1884
  • Illness caused: Pneumonia, Flesh Eating Disease
  • Antibiotic Resistance: Medium
  • Virulence: Dangerous
• Antonie van Leeuwenhoek: '"Whenever I found something remarkable, I have thought it is my duty to put down my discover on paper, so that all ingenious people be informed thereof."'
• Even before microorganisms were seen, some investigators suspected their existence and responsibility for disease
• Lucretius


  Roman philosopher (about 98 –55 B.C.) who suggested that disease was caused by invisible living creatures
• Girolamo Fracastoro


  Suggested that disease was caused by invisible living creatures
• The earliest microscopic observations appear to have been made between 1625 and 1630 on bees and weevils by the Italian Francesco Stelluti, using a microscope probably supplied by Galileo
• In 1665, the first drawing of a microorganism was published in Robert Hooke's Micrographia
• Antony van Leeuwenhoek


  The first person to publish extensive, accurate observations of microorganisms
• For the next 200 years after Leeuwenhoek's observations, the development of microbiology essentially languished due to insufficient techniques
• Techniques for isolating and culturing microbes in the laboratory were needed for the discipline of microbiology to develop
• Theory of Spontaneous Generation


  The belief that living organisms could develop from nonliving matter
• Aristotle (384–322 B.C.) thought some of the simpler invertebrates could arise by spontaneous generation
• Francesco Redi


  • Challenged the view of spontaneous generation by carrying out experiments on decaying meat and its ability to produce maggots spontaneously
  • Placed meat in three containers (uncovered, paper, fine gauze)
  • The other two pieces of meat did not produce maggots spontaneously
  • Flies were attracted to the gauze-covered container and laid their eggs on the gauze, producing maggots
  • Showed that generation of maggots by decaying meat resulted from the presence of fly eggs, not spontaneous generation
• Lazzaro Spallanzani


  • Improved on Needham's experimental design by first sealing glass flasks that contained water and seeds
  • Showed that BOILING could definitely get rid / prevents the growth
• Louis Pasteur


  • 19th Century French scientist who officially disproved spontaneous generation (thanks to "germ theory)
  • His swan-necked flask was the key
  • Thanks to Louis Pasteur we have vaccines also, as well as Pasteurization
• John Tyndall


  • Dealt a final blow to spontaneous generation in 1877 by demonstrating that dust did indeed carry germs and that if dust was absent, broth remained sterile even if directly exposed to air
• Golden Age of Microbiology

  The period from 1857–1914 when a number of disease-causing microbes were discovered, understanding of microbial metabolism were made, and techniques for isolating and characterizing microbes were improved
• Robert Koch


  • Provided the first direct demonstration of the role of bacteria in causing disease through his study of anthrax
  • His criteria for proving the causal relationship between a microorganism and a specific disease are known as Koch's postulates
• Development of Techniques for Studying Microbial Pathogens

  1. Koch cultured bacteria on sterile surfaces of cut, boiled potatoes

  2. Eventually developed culture media using meat extracts and protein digests

  3. Fannie Eilshemius Hesse suggested the use of agar as a solidifying agent

  4. Richard Petri devised the petri dish (plate) for holding solidified media
• Immunological Studies


  • Progress was made in determining how animals resisted disease and in developing techniques for protecting humans and livestock against pathogens
• Pierre Paul Émile Roux

  • During studies on chicken cholera, Pasteur and Roux discovered that incubating their cultures for long intervals between transfers would attenuate the bacteria, meaning they had lost their ability to cause the disease
• Rabies Vaccine


  1. Pasteur prepared rabies vaccine by growing the pathogen in an abnormal host, the rabbit

  2. After infected rabbits had died, their brains and spinal cords were removed and dried

  3. Joseph Meister, a nine-year-old boy who had been bitten by a rabid dog, was injected 13 times over the next 10 days with increasingly virulent preparations of the attenuated virus and survived
• Immunology


  • Emil von Behring and Shibasaburo Kitasato injected inactivated toxin into rabbits, inducing them to produce an antitoxin
  • Elie Metchnikoff discovered that some blood leukocytes could engulf disease-causing bacteria, calling the cells PHAGOCYTES and the process PHAGOCYTOSIS
• Development of Industrial Microbiology and Microbial Ecology


  1. Industrial microbiology developed from the work of Louis Pasteur and others on alcoholic fermentations

  2. Microbial ecology developed when early microbiologists studied the ecological role of microorganisms in cycles like carbon, nitrogen, and sulfur
• Martinus Beijerinck


  • Isolated the aerobic nitrogen-fixing bacterium Azotobacter, a root nodule bacterium also capable of fixing nitrogen (later named Rhizobium), and sulfate-reducing bacteria
• Divisions of Microbiology


  • Basic
  • Applied
• Basic Aspects of Microbiology

  • Bacteriology – study of bacteria
  • Mycology – study of fungi
  • Protozoology – study of protozoa
  • Phycology – study of algae
  • Parasitology – study of parasites
  • Immunology – study of immune system
  • Virology – study of viruses
  • Nematology – study of nematodes
• Applied Aspects of Microbiology

  • Concerned with practical problems such as disease, water and wastewater treatment, food spoilage and food production, and industrial uses of microbes
• Major Fields of Microbiology and Occupations

  • Medical microbiologists
  • Public health microbiology
  • Immunology
  • Agricultural microbiology
  • Microbial ecology
  • Food and dairy microbiology
  • Industrial microbiology
  • Microbial physiology and biochemistry
• Microorganisms living in the digestive tracts of ruminants such as cattle
• Microbial ecology


  Concerned with the relationships between microorganisms and the components of their living and nonliving habitats
• Microbial ecologists


  • Study the global and local contributions of microorganisms to the carbon, nitrogen, and sulfur cycles
• Scientists working in food and dairy microbiology

  • Try to prevent microbial spoilage of food and the transmission of foodborne diseases such as botulism and salmonellosis
  • Use microorganisms to make foods such as cheeses, yogurts, pickles, and beer
• Industrial microbiologists


  • Use microorganisms to make products such as antibiotics, vaccines, steroids, alcohols and other solvents, vitamins, amino acids, and enzymes
• Microbiologists working in microbial physiology and biochemistry

  • Study many aspects of the biology of microorganisms
  • Study the synthesis of antibiotics and toxins, microbial energy production, the ways in which microorganisms survive harsh environmental conditions, microbial nitrogen fixation, and the effects of chemical and physical agents on microbial growth and survival
• Microbial genetics and molecular biology

  • Focus on the nature of genetic information and how it regulates the development and function of cells and organisms
• Importance of Microbiology


  • Microbiology has an impact in the daily lives of humans
  • Some microorganisms are essential in biotechnology and a wide range of industry
  • Some microorganisms are important sources of antimicrobial agents
  • Some microorganisms act as saprophytes or decomposers of waste products and dead organisms
  • Understanding of how microorganisms produce disease
  • Relevant in other aspects (negative instances) in which science can be used