MICROPARA LEC

• Microbiology


  Study of organisms and agents that are usually too small to be clearly seen by the unaided eye
• Microbiology


  Study of objects that is less than 1 mm in diameter
• Categories of microorganisms


  • Virus
  • Bacteria
  • Archaean
  • Protozoa
  • Fungi
  • Algae
• Virus


  • Noncellular entities that consist of nucleic acid core (DNA or RNA) surrounded by a protein coat
  • Nonliving organism
  • Cannot reproduce outside a host cell and cannot metabolize on their own
  • Often infest prokaryotic and eukaryotic cells causing diseases
• Bacteria


  • Unicellular organisms
  • Prokaryotic cells because they lack nucleus
  • Four major shapes: bacillus (rod shape), coccus (spherical shape), spirilla (spiral shape), vibrio (curved shape)
• Archaean


  • Differ from true bacteria in their cell structure and lack peptidoglycan
  • Prokaryotic cells with avidity to extreme environmental conditions
  • Divided into: methanogens (methane producing organism), halophiles (live in salty environment), thermophiles (live at extremely hot temperature), psychrophiles (live in cold temperature)
• Protozoa


  • Unicellular aerobic eukaryotes
  • Make up the largest group of organisms in the world in terms of numbers, biomass, and diversity
  • Cell walls are made up of cellulose
  • Divided based on mode of locomotion: flagellates, ciliates, amoeboid, sporozoans
• Fungi


  • Eukaryotic cells with true nucleus
  • Most fungi are multicellular and their cell wall is composed of chitin
  • Fungi reproduce by releasing spores
• Algae


  • Also called cyanobacteria or blue green algae
  • Unicellular or multicellular eukaryotes
  • Obtain nourishment by photosynthesis
  • Live in water, damp soil, and rocks and produce oxygen and carbohydrates used by other organisms
• Why study microbiology?


  • There is still much to learn and understand
  • It is an opportunity to study processes common to all life
  • Microorganisms are important in disease and in environmental processes
  • Involved in decomposition of dead organism
  • Decomposing industrial waste
  • Algae and bacteria serve as food for tiny animals
  • Aid in digestion
  • Produce fermented foods
  • Produce products used in manufacturing and treatment
  • As an important tool in genetic engineering (biotechnology)
• Allows humans to


  • Prevent food spoilage
  • Prevent disease occurrence
  • Led to aseptic techniques to prevent contamination in medicine and in microbiology laboratories
• Visible organisms


  • Some algae and fungi- larger (e.g. bread molds and filamentous algae)
  • Two bacteria that are visible w/o microscope (Thiomargarita, Epulopiscium)
• Techniques in microbiology


  • Sterilization
  • Use of culture media
• Pioneers in the science of microbiology

  • Anton Van Leeuwenhoek (1st to observe live microorganisms through magnifying lenses, father of microbiology, develops simple microscope)
  • Robert Hooke (with a help of crude microscope observing a thin slice of cork, reported to world the life's smallest structural units "little box" or "cells", marked the beginning of cell theory)
  • Louis Pasteur (difference microorganism produce different fermentation product, microorganisms are indeed present in the air and can contaminate sterile solution, introduced the terms aerobes and anaerobes, discovered infectious agent causing silkworm disease, developed vaccines)
• Spontaneous generation (abiogenesis theory)

  • Aristotle (thought of some smaller invertebrates could arise by spontaneous generation, proposed that life arose form nonliving material if it contained "pneuma" - vital heat)
  • John Needham (based on observations of rotting food seemingly producing living organisms, argued that life originates from a "life force")
• Conflict over spontaneous generation

  • Francesco Redi (an opponent of spontaneous generation, conducted series of experiments on decaying meat and its ability to develop maggots)
  • Lazzaro Spallanzani (modified the Needham experiment, sealed flask placed on boiling water would inhibit growth of microorganisms, also absence of air)
  • John Tyndall (milk even if pasteurized will still become spoiled, found out that there are 2 types of microorganisms - spore-resistant and vegetative, proposed tyndallization)
  • Louis Pasteur (showed that microorganisms can be present in non-living matter, disproved the theory of spontaneous generation)
• Role of microorganism in disease

  • Joseph Lister (worked on the prevention of wound infections - antiseptic surgery, "Father of Modern Surgery")
  • Robert Koch (studied anthrax causing disease, injected healthy mice with material from disease animals and mice became ill, established Koch's Postulates)
  • Ignaz Semmelweis (demonstrated that physicians, who did not disinfect their hands, routinely transmitted infection)
• Exceptions to Koch's Postulates

  • Many healthy people carry pathogen but do not exhibit symptoms of the disease (carriers)
  • Some microbes are impossible to grow in vitro in artificial media
  • Experimental animals must be susceptible to the pathogen induced. Many pathogens are species-specific
  • Certain diseases develop only when an opportunistic pathogen invades a weakened host
• The development of techniques for studying microbial pathogens


  • Surfaces of cut boiled potatoes - bacteria do not grow well
  • Gelatin was used to solidify regular liquid media - (+) colonies but it may be digested by bacteria and liquefies at above 28 °C
  • Fannie Eilshemius Hesse (wife of Koch's assistant, introduced agar showing it was not attacked by most bacteria and do not melt even up to 100°C)
  • Julius Richard Petri (assistant of Koch, developed petri dish (plate) for solid culture media)
• Golden age of microbiology - Pasteur and R. Koch spearheaded the rapid advances in microbiology, discoveries on agents and many diseases occurred, the role of immunity in the prevention and cure of disease, studied the chemical activities of microbes, developed vaccines and surgical techniques
• Fermentation


  Is a chemical process by which molecules such as glucose are broken down anaerobically. It is a way of extracting energy from carbohydrates in the absence of oxygen (e.g. yeast converts the sugars to alcohol in the absence of air, in the presence of air and bacteria (Acetobacter) change the alcohol into vinegar)
• Pasteurization


  Pasteurization is process of applying heat to some alcohol drinks or milk just enough to kill pathogenic microorganisms without major changes to the product

  
• Julius Richard Petri


  Assistant of Koch, developed petri dish (plate) for solid culture media
• Golden Age of Microbiology


  • Pasteur and R. Koch spearheaded the rapid advances in microbiology
  • Discoveries on agents and many diseases occurred
  • The role of immunity in the prevention and cure of disease
  • Studied the chemical activities of microbes
  • Developed vaccines and surgical techniques
• Fermentation


  1. Molecules such as glucose are broken down anaerobically

  2. Yeast converts the sugars to alcohol in the absence of air (grape juice → wine)

  3. In the presence of air and bacteria (Acetobacter) change the alcohol into vinegar
• Pasteurization


  Process of applying heat to some alcohol drinks or milk just enough to kill potentially harmful bacteria to prevent spoilage

  
• Agostino Bassi


  Fungus causing silkworm disease
• Pasteur


  Protozoan causing silkworm disease
• Joseph Lister


  • Use of phenol to prevent surgical wound infection
  • Father of Aseptic Technique
  • First to introduce aseptic technique to control microbe by the use of physical and chemical agent
• Physical agent


  Process that are done physically (autoclaving, incineration, pasteurization)
• Chemical agent


  Example is alcohol
• Antiseptic


  Animate matter (tissue, skin, living things)
• Disinfectant


  Inanimate matter (nonliving things)
• Rober Koch


  Cause of anthrax destroying cattle and sheep
• Ignaz Semmelweis


  Demonstrated that washing and disinfecting hands with a solution of chlorinated lime reduced occurrence of "puerperal sepsis"
• Puerperal sepsis


  Genital tract infection that can occur from amniotic fluid rupture to six weeks after birth
• Vaccination


  Developed as treatment or preventive procedure
• Edward Jenner (1798)


  • Used cowpox virus (Vaccinia) to vaccinate people against small pox
  • He inoculated a healthy volunteer with the cowpox material by scratching the person's arm with a pox-contaminated needle
• Emil von Behring


  Developed method for producing immunity by using antitoxin against diphtheria
• Pasteur (1880)


  • He discovered why vaccination work
  • Bacteria causing fowl cholera lost its ability to cause disease after it was grown in the laboratory
  • Losing its virulence will able to induce immunity against subsequent infections by its virulent counterparts
  • Vaccine was a term used by Pasteur for cultures of avirulent microorganism
  • Vaccine would stimulate immunity to the relevant virulent strain