Relevance and History ofMicrobiologyGeneral MicrobiologyBIO 211Dr. Miller
ObjectivesIntroduction to Microbiology• Learn the scope and range of microbiology study(ubiquity and diversity)• Describe broad taxonomic classifications ofmicroorganisms• Understand the importance of microorganismsand the effect they have on human populations• Describe the advent of the microbiology fieldfrom a historical perspective
What is microbiology?1. Micro: too small to be seen with the nakedeye2. Bio: life3. Logy: study ofIn general microbiology is the study ofmicroorganisms
Microorganisms are DIVERSE!!!• Microorganisms are found across everytaxonomic group– Bacteria (Bacteria and Archaea)– Fungi (Fungi/Myceteae)– Protozoa (Protista)– Algae (Protista)– Parasites (Animalia)– Viruses ( ? )
System of Classification• Five Kingdom systemhttp://www.davidlnelson.md/Cazadero/CazImages/FiveKingdoms%20Animals2.jpg
System of ClassificationDomainKingdomPhylumClassOrderFamilyGenusSpeciesHumans E. coli (6 Kingdom)Eukarya Bacteria/EubacteriaAnimalia Bacteria/EubacteriaChordata ProteobacteriaMammalia Gama ProteobacteriaPrimates EnterobacterialesHominidae EnterobacteriaceaeHomo EscherichiaH. sapiens E. coli
Microorganisms are UBIQUITIOUS!!!• Microorganisms are found nearly everywhere– On/in bodies– On surfaces– In the air– In water– In extreme environments: deep sea thermalvents, polar ice caps, sulfur and salty lakes
Microorganisms are IMPORTANT!!!(positive)1. Nutrient production and energy flow– Engage in photosynthesis– Produce oxygen– Food chain2. Decomposition and nutrient recycling– Recycle chemical elements and direct them back to naturalcycles of living organisms.3. Biotechnology/Genetic Engineering– Can be manipulated to produce proteins for our use (i.e.insulin, human growth hormone)– Used as a genetic model organism4. Bioremediation– Used to restore stability or clean up pollutants
Microorganisms are IMPORTANT!!!(negative)Impact on Human Health• Only 1% of known bacteria cause human disease• Annual world wide death toll from infections is 12million people– 3 million from malaria alone
• Notice how many deaths are caused by microorganisms• Notice the difference between the US and worldwideToday we understand the impact microorganisms have on ourlife. Historically their importance was not recognized!
Historical Perspective• 400 B.C. Hippocrates– Medicine is distinct from theology and philosophy– Set forth ethical standards for the practice of medicine• 100 B.C. Roman scholars– Proposed that tiny animals entered the mouth and noseto cause disease• Disease, infection, and death was recognized ascontagious and perhaps even caused by “minutebodies” or “foul foreign earthly bodies” however, theirstudy was inhibited due to a lack of scientific tools.– 542-1650 A.D. The Black Death (bubonic plague) killed 10sof millions of people in the Mediterranean and Europe.Jewish population less affected due to Hebrew sanitationlaws
Spontaneous Generation• Existed ~300B.C. through the mid 1800s• Theory that microorganisms arose from non-living things (seeing is believing)– Maggots from dead meat– Bacteria from old broth• As long as people believed that living couldarise from non-living there was no need tounderstand how diseases were transmittedand controlled!!!
Beginning of Microbiology• Scientists (and others) began to changetraditional ideas about disease andmicroorganisms in the mid 1600s1. Tools• Anton van Leeuwenhoek (Dutch merchant): 1670s. 1stlenses and later the 1st to examine/document livingmicroorganisms• Robert Hooke (English scientist): Used a compoundmicroscope . Coined the term cell.2. New hypothesis (theory): Germ Theory of Disease• Microorganisms can invade other organisms and causedisease• Met with lots of resistance from the scientific community(previous theory lasted for 2100 years)
Germ Theory of DiseaseProponents• Francesco Redi (Italian physician): 1688http://biology.clc.uc.edu/graphics/bio104/redi.jpghttp://www.rmutphysics.com/CHARUD/scibook/bio2/chapter6/image/spallanzani-experiment.jpg• John Needham(English priest): 1748• Lazzaro Spallanzani(Italian priest): 1760s• Challenges spontaneous generation• Tested decaying meat’s ability to producemaggots• Challenges spontaneous generation• Boiled broth and sealed it
Germ Theory of DiseaseProponents• Ignaz Philipp Semmelweis (Austrianphysician): 1847– Introduced hand washing practices– Childbed fever• (decrease the mortality rate from 35% to 1%)– Largely ignored during his lifetime• Joseph Lister (English surgeon): 1867– Introduced phenol as a disinfectant– Decrease post-operative infections
Germ Theory of DiseaseProponents-The Final Blowhttp://3.bp.blogspot.com/_wYOqE4H4V6U/Rdo8-Y1pj8I/AAAAAAAAACQ/hsehi4O0DV0/s200/1_6.gif• John Tyndall (Englishphysicist): 1860s• Louis Pasteur (Frenchchemist): 1861• Swan neck flasks• Placed sealed flasks of boiled infusions inan airtight box. After the dust settledhe removed the covers from the flasks.The flasks remained sterile.First evidence against spontaneousgeneration was in 1688. Wasn’tfinally accepted by the scientificcommunity until 1861.
Other Significant Events inMicrobiology History• 1796: Edward Jenner introduces cowpoxvaccination for smallpox• 1838 & 1839: Schwann and Schleidenpropose cell theory– Plants and animals are made up of cells– These cells are essential to the structure andfunction of organisms• 1884: Hans Christian Gram develops theGram stain technique
Other Significant Events inMicrobiology History1876: Identifies Bacillusanthracis as the causative agentof anthrax1882: IdentifiesMycobacterium tuberculosis asthe causative agent oftuberculosis1884: Develops Koch’spostulates. Still used today inidentifying causative agents ofdisease1857: Developed pasteurization1861: Refuted spontaneousgeneration1881: Developed anthrax vaccine1885: Developed rabies vaccineLouis PasteurRobert Koch
Other Significant Events inMicrobiology History• 1903: Wright and others discover antibodies• 1929: Alexander Fleming discovers the first antibiotic(penicillin)• 1953: Watson and Crick propose DNA double helix• 1954: Jonas Salk develops polio vaccine• 1976: First whole genome to be sequenced (RNA virus)• 1979: Smallpox is officially declared eradicated• 1983: HIV is isolated and identified• 1990: First human gene therapy• 1995: First bacterial genome is sequenced• 2002: Infectious poliovirus is made from basic chemicalsSIGNIFICANT findings are still being made today!
Conclusions• Microorganisms span all taxonomic kingdoms• Microorganisms can be found everywhere• Microorganisms have vast impact on the environment,the ecosystem, and human life (give examples)• Our current understanding of microbiology is the resultof the work of thousands of microbiologists overhundreds of years• The advent of the microscope is what really began thestudy of microbiology• The Golden Era of Microbiology resulted in hugeadvancements in this field• Great achievements are still being reached today