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The Microbial World. Microbiology , Microbes, infections
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- 2. BEST FOR You OR G A N I C S C O M P A N Y 2 A Glimpse of History The Origin of Microorganisms
- 3. BEST FOR You OR G A N I C S C O M P A N Y 3 • Antony van Leeuwenhoek – Microbiology as a science – 1674 – lake water through a glass lens – carefully ground • Robert Hooke – Observed first microorganism in 1665 – microfungus, which he called microscopic mushroom • He also described how to make the kind of microscope that van Leeuwenhoek made almost 10 years later
- 4. BEST FOR You OR G A N I C S C O M P A N Y 4 The Origin of Microorganisms
- 5. • Microorganisms haveexisted on earth for about 3.5 billion years – may be over this time. • Where did these microscopic forms originate? • Spontaneous? • Non-spontaneous? Some Famous Experiments • Francesco Redi – worms originated from the eggs of flies • John Needham – 1749 (boiled infusions + sealed with cork) • Father Spallanzani – 1776 (boiled for longer time + melted necks) • Destruction of “Vital Force” by heating
- 6. BEST FOR You OR G A N I C S C O M P A N Y 6 LouisPasteur-1861 » Giant in Science » Father of modern microbiology 1. Air is filled with microorganisms • Air filtration through a cotton plug • Examination under microscope • Growth in infusions 2. Specially constructed Swan necked flasks
- 7. BEST FOR You OR G A N I C S C O M P A N Y 7
- 8. BEST FOR You OR G A N I C S C O M P A N Y 8 JohnTyndall » English physicist-1876 » Different infusions required different boiling times to be sterilized » 5 minutes to 5 hours in the case of hay infusions » Hay in the lab can enhance the sterilization time. Why? How? » Two forms: A cell that is readily killed by boiling, and one that is heat resistant
- 9. • Ferdinand Cohn– 1876 – A botanist – Also found the heat resistant forms – endospore • Anthrax – Bacillus anthracis – resistant spores
- 12. BEST FOR You OR G A N I C S C O M P A N Y 12 Microbiology–AHumanProspective Life can not exist without microbes Pathogens…? Beneficial Impacts…? • Bacteria • Archaea • Protozoa • Algae • Fungi • Multicellular parasites • Non-living agents i.e. viruses, viroids, and prions
- 13. • Diversity amongmicroorganisms • Far different from one another –than plants and animals • Microbes –the most abundant form of life on earth as well as the oldest • 500-1000 species live on a healthy human • True contribution and biological role –underestimated (1% cultivated) Important Roles • Nitrogen fixation • Carbon recycling • Supplying the O2
- 14. • Cellulose breakdown–cellulase –in environment as well as in digestive tracts of cattle, sheep, deer, and other ruminants • Degradation of materials in sewage water Applications of Microbiology • Food Production • Bioremediation • Useful Products • Medical Microbiology
- 15. Food Production • EgyptianBakers (2100BC) –Yeast • Beer production in Egypt –Fermentation • Milk fermentation – Yogurt cheeses, and buttermilk • Probiotics Bioremediation • Polychlorinated biphenyls (PCBs) • Dichloro diphenyl trichloro ethane (DDT) • Trichloro ethylene • Degrade oil • Radioactive wastes • A bacterium was discovered that can live on trinitrotoluene (TNT)
- 16. Other Useful Products •Cellulose –used in stereo headsets • Hydroxybutyric acid used in the manufacture of disposable diapers and plastics • Ethanol, as a substitute for gasoline—a “biofuel” • Chemicals poisonous to insects • Antibiotics used in the treatment of disease • Amino acids, used as dietary supplements
- 17. Medical Microbiology • Sinisterrole –influenza in 1918–1919 • Smallpox, bubonic plague, and influenza
- 18. BEST FOR You OR G A N I C S C O M P A N Y 18 MicroorganismsAsModelOrganisms Model Organisms –same metabolic and genetic properties • All cells are composed of same elements • Synthesize their cell structures by the same basic mechanisms • Duplicate their DNA by similar processes • Degrade food materials to harvest energy via the same metabolic pathways The study of microorganisms has many advantages i. Results can be obtained quickly –Microbes grow rapidly ii. Can be grown on –simple inexpensive media Understanding of life have come through the study of microorganisms
- 19. BEST FOR You OR G A N I C S C O M P A N Y 19 Membersof TheMicrobialWorld Three domains of the life; • Bacteria (Eubacteria) • Archaea (Archaebacteria –ancient bacteria) • Eucarya Microscopically similar • Prokaryotic cell • Nucleoid • Genetically quite different
- 20. BEST FOR You OR G A N I C S C O M P A N Y 20 Bacteria a) They are all single-celled prokaryotes b) Specific shapes i.e. cylindrical, spherical, spiral. c) Rigid cell wall –peptidoglycan d) Binary fission –Identical to the original cells e) Flagella for movement
- 21. BEST FOR You OR G A N I C S C O M P A N Y 21 Archaea a) Same shape and size b) Also multiply with Binary fission –Identical to the original cells c) No peptidoglycan in cell wall d) Can grow in extreme environments e) Great Salt Lake and the Dead Sea f) Boiling hot springs at Yellowstone National Park g) Cold waters of Antarctica and Alaska
- 22. BEST FOR You OR G A N I C S C O M P A N Y 22 Nomenclature a) The first word –genus –first letter capitalized b) The second indicates the species –not capitalized c) Both words are always italicized or underlined d) Escherichia coli e) Specie VS Strain, E. coli strain B
- 24. BEST FOR You OR G A N I C S C O M P A N Y 24 Viruses,Viroids,andPrions Viruses are; a) Obligate intracellular parasites b) All forms of life including members of the Bacteria, Archaea, and Eucarya can be infected by viruses
- 26. BEST FOR You OR G A N I C S C O M P A N Y 26 Identification and Classification of Microbes
- 27. BEST FOR You OR G A N I C S C O M P A N Y 27 GroupingCriteria a)Would you group them according to shape? b)Or would it make more sense to group them according to their motility? c) According to their medical significance? d)But then, how would you classify two apparently identical bacteria that differed in their disease-causing potential?
- 28. BEST FOR You OR G A N I C S C O M P A N Y 28 Initialefforts a) Ferdinand Cohn –classification based on shape –too many kinds but too few shapes. b) 2nd attempt by Sigurd Orla-Jensen –physiological properties rather than morphology c) Albert Kluyver and C. B. van Niel –evolutionary relationship –distinguished b/w resemblance and relatedness d) 1970, Roger Stanier –gene products can be compared –was assumed that all microbes are similar e) Many features –chemical nature of cell wall/membrane, rRNA f) Carl Woese –rRNA sequence
- 29. BEST FOR You OR G A N I C S C O M P A N Y 29 Principlesof Taxonomy a) Identification b) Classification c) Nomenclature Strategies used for the Identification • Microscopic examination • Culture characteristics • Biochemical tests • Nucleic acid analysis
- 30. Strategies used forthe classification Taxonomic Hierarchies • Specie –prokaryotes VS eukaryotes, not identical, stains VS specie • Genus • Family • Order • Class • Phyla • Kingdom • Domain –characteristics of a cell that makeup an organism
- 32. Bergey’s Manual ofSystematic Bacteriology All known species are described there. The new edition is published based on genetic relatedness Information on; o The ecology o Methods of enrichment o Culture o Isolation of the organisms o Methods for their maintenance and preservation
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- 37. BEST FOR You OR G A N I C S C O M P A N Y 37 Nomenclature • International Code for the Nomenclature of Bacteria • Bacterial names may originate from any language –Latin suffix • Lactococcus lactis –Streptococcus –Lactococcus (Streptococcus) lactis
- 38. BEST FOR You OR G A N I C S C O M P A N Y 38 Principlesof Taxonomy a) Identification b) Classification c) Nomenclature Strategies used for the Identification • Microscopic examination • Culture characteristics • Biochemical tests • Nucleic acid analysis
- 39. BEST FOR You OR G A N I C S C O M P A N Y 39 Microscopicexamination a) Size and Shape –wet mount –Bacteria, fungus, protozoa b) Clinical diagnosis Gram staining c) Differentiate between Gram +ve and –ve d) Have limitations i.e. can not identify the Streptococcus pyogenes e) Can not differentiate between Salmonella and E.coli of stool samples Acid Fast Strain Mycobacterium –Tuberculosis
- 43. Metabolic capabilities • Culturecharacteristics o Serratia marcescens –red pigment at 22 o C o Pseudomonas auroginosa – green pigment o Streptococcus pyogenes –Blood agar –β hemolysis o E.coli –UTI –Pink colonies on MacConkey agar –lactose fermentation • Biochemical tests –for conclusive identification Catalase –present in all aerobes
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- 51. BEST FOR You OR G A N I C S C O M P A N Y 51 OtherMethods a) Serology b) FAME Serology Identification of the molecules that make up the surface structures i.e. cell wall, capsule, flagella, and pili. This method rely on the specificity of interaction between antibodies and antigens FAME Cellular fatty acid composition can be used for the identification Gram negative – cytoplasmic and outer membrane Cells grown –treated – sodium hydroxide and methanol –fatty acids and volatile methyl esters –GC-MS
- 52. BEST FOR You OR G A N I C S C O M P A N Y 52 GenotypicCharacteristicsforthe Identification a) DNA probe and PCR b) Probe-Single-stranded piece of nucleic acid, usually DNA, Labelled with a dye/radioisotope c) Complementary to the sequence of interest d) Fluorescence in situ hybridization (FISH)-16sRNA e) PCR of specific DNA f) Sequencing Ribosomal RNA Genes-16s, SSU g) Using rDNA to identify Uncultivated Organisms- Whipple’s disease- Tropheryma whipplei
- 54. BEST FOR You OR G A N I C S C O M P A N Y 54 CharacterizingStrainDifferences a) Salmonella enterica serotype Enteritidis b) Biochemical typing -biovar or a biotype c) Vibrio cholera-Eltor A group of strains that have a characteristic biochemical pattern
- 60. BEST FOR You OR G A N I C S C O M P A N Y 60 ClassifyingtheMicrobes a) Stromatolites b) General Principles –draw backs
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- 65. BEST FOR You OR G A N I C S C O M P A N Y 65 CustomizethisTemplate Template Editing Instructions and Feedback