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Microbiology Viruses and Bacteria. History of Microbiology Edward Jenner (1798): 1 st Vaccine Joseph Lister (1867): Aseptic Surgery Luis Pasteur (1857-1864)

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Presentation on theme: "Microbiology Viruses and Bacteria. History of Microbiology Edward Jenner (1798): 1 st Vaccine Joseph Lister (1867): Aseptic Surgery Luis Pasteur (1857-1864)"— Presentation transcript:

1 Microbiology Viruses and Bacteria

2 History of Microbiology Edward Jenner (1798): 1 st Vaccine Joseph Lister (1867): Aseptic Surgery Luis Pasteur ( ) FermentationFermentation PasteurizationPasteurization BiogenesisBiogenesis Robert Koch Germ Theory of Disease (1876)Germ Theory of Disease (1876) Microorganism can cause disease Microorganism can cause disease Koch’s Postulates Koch’s Postulates Pure Cultures (1881)Pure Cultures (1881) Tuberculosis (1882)Tuberculosis (1882) Alexander Flemming (1928): Penicillin Jonas Salk (1955): Polio Vaccine

3 Koch’s Postulates

4 Viruses Virus: A parasitic non-living entity! Virus: A parasitic non-living entity! Must exist within a “host” Must exist within a “host” No Cellular Structure No Cellular Structure No cytoplasm, organelles, or phospholipid membranes No cytoplasm, organelles, or phospholipid membranes Capsid: Outer coat made of proteinCapsid: Outer coat made of protein Core: Central region made of nucleic acidCore: Central region made of nucleic acid DNA or RNA DNA or RNA Envelope: Made of lipids, carbo, and proteinsEnvelope: Made of lipids, carbo, and proteins Spikes: Used for attachmentSpikes: Used for attachment Carbohydrate and protein (glycoprotein) Carbohydrate and protein (glycoprotein)

5 Viruses

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7 Virus Structure

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9 Virus Shapes Rod-shaped: (helical) Rod-shaped: (helical) Tobacco mosiac virus (TMV)Tobacco mosiac virus (TMV) Spherical: (round or oval) Spherical: (round or oval) HIV or Aids virusHIV or Aids virus Polyhedral: (many sides) Polyhedral: (many sides) Polio virusPolio virus Bacteriophage Bacteriophage Infects bacterial cellsInfects bacterial cells

10 Bacteriophage A virus that infects a bacterial cell Used to study viral behavior T-4 bacteriophage is commonly studied!

11 The Lytic Cycle 1. Attachment Adsorption Adsorption 2. Entry 3. Biosynthesis Replication Replication Transcription Transcription Assembly Assembly Formation Formation 4. Lysis and release The cell explodes The cell explodes

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13 Lysogenic Cycle 1. Attachment 2. Entry 3. Integration 4. Cell division Replication Replication 5. Lysis? Provirus: A virus that becomes integrated into the host cells DNA Provirus: A virus that becomes integrated into the host cells DNA

14 Viruses can contain DNA or RNA DNA Virus Lytic cycle Attachment/Adsorption Attachment/Adsorption Entry Entry Biosynthesis Biosynthesis Lysis and release Lysis and release Lysogenic Cycle Attachment Attachment Entry Entry Integration Integration Cell division and possible lysis Cell division and possible lysis RNA Virus Lytic Cycle Similar to DNA viruses Similar to DNA viruses Viral RNA can serve as mRNA to construct proteins! Viral RNA can serve as mRNA to construct proteins! Lysogenic Cycle Retrovirus: A virus that can transcribe DNA from RNA (provirus) Retrovirus: A virus that can transcribe DNA from RNA (provirus) Reverse transcriptase: An enzyme that can reverse normal transcription (reverse transcription)!! Reverse transcriptase: An enzyme that can reverse normal transcription (reverse transcription)!! HIV is an example HIV is an example

15 HIV DNA makes RNA makes Protein A retrovirus can reverse this sequence The virus enters as RNA and then can manufacture DNA. It will integrate into the host cells DNA The virus enters as RNA and then can manufacture DNA. It will integrate into the host cells DNA HIV replicates times per day HIV replicates times per day It takes 6 weeks for HIV to become resistance to AZT (one of the most common drugs to treat HIV) It takes 6 weeks for HIV to become resistance to AZT (one of the most common drugs to treat HIV) HIV treatment options Triple drug therapy is a must! Triple drug therapy is a must! 1. Integrase inhibitors 2. Reverse transcriptase inhibitors 3. Protease inhibitors

16 Bacteria: Living!! Kingdom Archaebacteria Kingdom Eubacteria Structure Prokaryotic: Nucleoid region with a loop of chromosomal DNAProkaryotic: Nucleoid region with a loop of chromosomal DNA Cell wall (peptidoglycan)Cell wall (peptidoglycan) Capsule: (outer protective coat found on some bacteria)Capsule: (outer protective coat found on some bacteria) Flagella: One…or manyFlagella: One…or many Endospore: Protective wall that surrounds some bacteria. Allows bacteria to remain dormant for long periodsEndospore: Protective wall that surrounds some bacteria. Allows bacteria to remain dormant for long periods

17 Flagella: Swimming movement Flagella: Swimming movement ProteinProtein Pili: Sex pilus Mediates DNA transfer during conjugation Pili: Sex pilus Mediates DNA transfer during conjugation ProteinProtein Common pili or fimbriae: Attachment to surfaces; protection against phagotrophic engulfmentCommon pili or fimbriae: Attachment to surfaces; protection against phagotrophic engulfment Protein Protein Capsules: (includes "slime layers" and glycocalyx) Capsules: (includes "slime layers" and glycocalyx) Attachment to surfaces; protection against phagocytic engulfment, occasionally killing or digestion; reserve of nutrients or protection against desiccationAttachment to surfaces; protection against phagocytic engulfment, occasionally killing or digestion; reserve of nutrients or protection against desiccation Usually polysaccharide; occasionally polypeptide Usually polysaccharide; occasionally polypeptide Cell wall: Cell wall: Gram-positive bacteria Prevents osmotic lysis of cell protoplast and confers rigidity and shape on cells Peptidoglycan (murein) complexed with teichoic acidsGram-positive bacteria Prevents osmotic lysis of cell protoplast and confers rigidity and shape on cells Peptidoglycan (murein) complexed with teichoic acids Gram-negative bacteriaPeptidoglycan prevents osmotic lysis and confers rigidity and shape; outer membrane is permeability barrier; associated LPS and proteins have various functions Peptidoglycan (murein) surrounded by phospholipid protein-lipopolysaccharide "outer membrane“Gram-negative bacteriaPeptidoglycan prevents osmotic lysis and confers rigidity and shape; outer membrane is permeability barrier; associated LPS and proteins have various functions Peptidoglycan (murein) surrounded by phospholipid protein-lipopolysaccharide "outer membrane“ Plasma membrane: Permeability barrier; transport of solutes; energy generation; location of numerous enzyme systems Phospholipid and protein Plasma membrane: Permeability barrier; transport of solutes; energy generation; location of numerous enzyme systems Phospholipid and protein Ribosomes: Sites of translation (protein synthesis)RNA and protein Ribosomes: Sites of translation (protein synthesis)RNA and protein Inclusions: Often storage reserves of nutrients; additional specialized functions Inclusions: Often storage reserves of nutrients; additional specialized functions Highly variable; carbohydrate, lipid, protein or inorganicHighly variable; carbohydrate, lipid, protein or inorganic Chromosome: Genetic material of cell DNA Chromosome: Genetic material of cell DNA Plasmid: Extrachromosomal genetic material DNA Plasmid: Extrachromosomal genetic material DNA

18 Bacterial Reproduction Binary Fission: A form of asexual reproduction where the cell splits into two. (DNA must replicate first) Plasmid Sharing: The process where bacterial cells exchange plasmid DNA using pili. (Linked to antibiotic resistance) Conjugation: Exchange of “nucleoid” or chromosomal DNA

19 Plasmid Sharing and Binary Fission

20 Bacterial Cell Shape Bacillus: Rod-shaped Bacillus: Rod-shaped Spirilla: Spirals Spirilla: Spirals Cocci: Round or spherical Cocci: Round or spherical Strept: Chains Strept: Chains Staph: Clusters Staph: Clusters Diplo: Two together Diplo: Two together

21 Bacterial Shapes

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23 Nutrition Heterotrophic: Obtain energy from organic matter. Parasitic: (+, -)Parasitic: (+, -) Saprophytic: Live off of dead or decaying matterSaprophytic: Live off of dead or decaying matter(chemo-heterotroph) Autotrophic: Can make their own nutrients Photoautotroph: Use sunlight for energy CO 2 for carbon Early blue green bacteria/cyanobacteria Produced oxygen for early earth’s atmosphere Chemoautotroph: Use inorganic compounds for energy Use CO 2 for carbon Found in hydrothermal vents Thrive on hydrogen sulfide

24 Ancient Bacteria (Archaebacteria) Methanogens: Produce methane Methanogens: Produce methane Swamps, marshes, digestive tracts of mammals. Breakdown decaying matterSwamps, marshes, digestive tracts of mammals. Breakdown decaying matter Halophiles: “ salt loving” Halophiles: “ salt loving” Great salt lake, dead seaGreat salt lake, dead sea Acidophiles: Thrive in acidic environments Acidophiles: Thrive in acidic environments Thermophile: Thrive at high temps Thermophile: Thrive at high temps Acidophiles and thermophiles are found in yellowstone springs, hydrothermal vents. Ph is often as low as 2.Acidophiles and thermophiles are found in yellowstone springs, hydrothermal vents. Ph is often as low as 2. Lack peptidoglycan cell walls Lack peptidoglycan cell walls Membrane lipids are different from Eubacteria Membrane lipids are different from Eubacteria DNA sequences of many archaebacteria genes are more similar to eukaryotes than to Eubacteria DNA sequences of many archaebacteria genes are more similar to eukaryotes than to Eubacteria

25 Hydrothermal Vents Giant Tube worms

26 The Gram Stain Procedure A differential stain used to separate bacteria into two groups A differential stain used to separate bacteria into two groups Based on cell wall differencesBased on cell wall differences Bacteria are separated into:Bacteria are separated into: Gram + Gram + Gram - Gram -Steps 1. Smear air dry, heat fix 2. One minute Crystal Violet RBD 3. One minute Gram’s Iodine RBD 4. Decolorize with ETOH (drops) RBD sec. Safranin RBD, AD

27 Gram (+) & Gram (-)

28 Kirby Bauer Test of antibiotic effectiveness


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