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Microbiology PP.ppt

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Microbiology PP.ppt Powered By Docstoc
					    Chapter 20
Viruses –section 1
Bacteria –section 2
VIRUSES
                     Viruses
                Is a Virus Alive?
• A Viruse is considered NON-Living
  – Viruses are NOT cells (the basic unit of life)
  – Do NOT grow
  – Do NOT have homeostasis
                                     Influenza virus
  – Do NOT metabolize
  – Can NOT reproduce
    without a host cell
  – No scientific name,
    instead family names
                 Virus Size
• The smallest organism that have the properties
  of life (themes of biology) are prokaryotes.

• Viruses are smaller than prokaryotes and
  prokaryotes are typically smaller than
  eukaryotes.

• You would NOT be able to view a virus under a
  light microscope.

        http://www.cellsalive.com/howbig.htm
              Viral Structure
• Virus contains a nucleic acid (DNA or RNA
  but not both) within a protein coat.
• Outer protein coat is called a capsid
• Most viruses have an envelope
  surrounding the capsid which consist of
  proteins, lipids and glycoproteins.
• Glycoproteins are proteins with attached
  carbohydrate molecules.
• Shape varies – helix, bullet, round
• Some features for protection
  – Envelope, spikes, slime layers
                                        DNA or RNA



                       Protein coat
                       aka: capsid

Bacteriophages -
 Viruses that infect
                             Tail
      bacteria
                          Tail fibers
          Attaching to Cells
• Prior to replication,
  virus must enter cell
• Protein on virus
  interlock with surface
  markers on cells
• Each virus has specific
  cell to “dock” with
• EX: polio virus
  attaches to nerve cells
     Viral Replication Cycles
• Lytic                 • Lysogenic
  – Virus attaches to     – Virus attaches to cell
    cell                  – Inserts DNA
  – Inserts DNA           – DNA integrates into
  – Replication of          host DNA
    viral parts           – Cell replicates
  – Assembly of new         normally with viral
    viruses                 DNA altering protein
  – Cellular lysis          synthesis
                          – Proteins can create
                            new viruses or not
                            (latency)
Lytic Cycle
Lytic Cycle
Lytic Cycle Continued
Lysogenic Cycle
Lysogenic Cycle
 How Viruses Damage Cells
• Inhibit protein synthesis of host
• Open lysosomes
• Bind membranes together
• Create a toxic level of proteins

 The human body protects itself from
  viruses using antibodies and fever.
   Viruses prefer body temperature.
Which of these diseases is likely to be
       caused by a lytic virus?
             Characteristics of some Viral Diseases


Disease     Symptoms                                  Incubation


Measles     Rash, Fever                               9-11 days


Shingles    Pain, itching on skin                     Years


Warts       Bumpy area on skin                        Months


Influenza   Body aches, fever, runny nose             1-4 days


HIV         fatigue, weight loss, fever               2-5 years
Viral Disease
• Chicken Pox
  –   Fluid filled blisters
  –   Itching and burning
  –   Common in kids
  –   Vaccine to
      prevent
• Herpes zoster –
  shingles
  – Reactivated chicken
    pox
  – Highly contagious
  – Viral DNA remains in
    neurons, dormant
  – Pain, fever, skin lesions,
    pus filled spots
  – Can be due to sun,
    stress, fever, trauma, but
    main cause unknown
• Cold Sores
  – Herpes simplex
  – Virus lives in a nerve in
    face
  – Reactivated similar to
    shingles
  – Fever, sore throat,
    mouth pain, edema
• Herpes simplex 2
  – Genital herpes
  – Virus lives in
    bottom of the spine
  – Same reactivation
  – Congenital herpes in
    newborns
  – Tingling, pain during
    urination, thick
    discharge, fluid filled
    vesicles
  – Found in 25 mil
    Americans
  Human Immunodeficiency Virus
                      HIV
• Composed of 2 molecules of single-stranded
  RNA
• Approximately 9,000 nucleotides
• Make up 9 genes
• 3 of these genes are
  common to many
  different viruses
HIV
 – Transmitted through sexual
   contact (STD), contaminated
   blood, or contaminated
   needles

 – Retrovirus RNA  DNA
 – Reverse transcriptase
 – Enters immune system by
   endocytosis into WBC

 – Prevents WBC from making a
   receptor (CD4) that normally
   detects pathogens
 – Symptoms treated with drug
   cocktail
HIV
Description of illness:
  – Exposure symptoms – headache,
    sore throat, occasional rash

  – Upon reactivation – rapid weight
    loss, dry cough, night sweats,
    unexplained fatigue, white spots
    in mouth, memory loss

  – Death usually from secondary
    infection – Kaposi’s sarcoma,
    candidas, Burkitt’s lymphoma
• Rabies
  – Virus lives in salivary glands
    of animal
  – Virus destroys the nerves
  – Produces Negri bodies in
    brain
  – Initial symptoms – tingling
    and cold around bite,
    nervous
  – Phase II – anxiety,
    photophobia, arrhythmia,
    pupil dilation, difficulty
    swallowing
  – Gamma globulin treatment
• Smallpox
  – Last seen in 1977
  – Eradicated by WHO due to obvious
    symptoms and short life cycle
  – CDC and Moscow
  – Self-replicating
• Mononucleosis
  – Fluid transmission
  – “kissing disease”
  – Infects WBC’s
  – Enlarged lymph
    nodes, swollen
    spleen, sore throat,
    nausea, weakness,
    fatigue
  – Can last up to 6 wks
  – Remains latent in
    nerves
  – Steroid treatment to
    boost immune
    function
• Measles
 – Highly contagious
 – Respiratory droplet
   spread
 – Nasal discharge, dry
   cough, fever,
   headache, pink eye,
   pink lesions, ear
   infection
 – Targeted for
   eradication
 – MMR vaccine
• Viral Hepatitis B
  – Initially
    asymptomatic
  – 1-3 month
    incubation
  – Fever, loss of
    appetite, pain,
    nausea, fatigue,
    jaundice, swollen
    liver
  – 3 step vaccine
• Hanta Virus
  – Deermice and
    ticks
  – No human to
    human
  – 2-3 day incubation
  – Cough, pulmonary
    edema,
    hemorrhaging,
    renal failure, achy
    muscles
  – 60% death rate
• Ebola
  – Sudan and Zaire
  – 93% death rate
  – Hemorrhagic fever
    • High temperature
    • Blood from orifices
  – Reston VA, non-human
    form
BACTERIA
                BACTERIA
• Prokaryotes
  – Small, circular DNA, ribosomes
• Kingdom Archeabacteria
  – Live in extreme environments (deep ocean,
    swamps)
  – Mostly live in environments without oxygen
  – Some are motile
• Kingdom Eubacteria
  – About 5,000 species
  – Live in most environments
  – Some are motile
          How are bacteria different from
                   eukaryotes?
         Prokaryotes             Eukaryotes
               Bacteria                    Protist - Fungi - Plants – Animals

Lack a cell nucleus & membrane-bound         Have a nucleus and membrane-
                 organelles                         bound organlles
             Smaller in size                     Typically larger in size

        Single cells: Unicellular             Unicellular and Multicelluar
                                                 Linear pieces of DNA
      Singel circular piece of DNA
                                                 Asexual Reproduction:
    Cell activities are not specialized    chromosomes are pulled to opposite
                                             poles of the cell during mitosis
        Asexually Reproduction:
         through binary fission
                                                    forming two cells
                                                  Sexual Reproduction
Metabolic diversity – both anaerobic and
             aerobic processes                 Mostly aerobic organisms
           Bacterial Structure
• Chromosome -Single circular piece of
  DNA
• Cell wall – rigid outer structure
• Capsule and spores – increases
• Pili – helps to stick to surfaces,
  aids in reproduction
• Flagellum – movement

Virulence – of a microorganism
like a bacterium or virus, is a measure
of severity of the disease it is capable
of causing
 Like ALL cells bacteria have:
• Ribosomes
• Cell Membrane
• Cytoskeleton
• Cytoplasm
• Genetic material
 Bacterial Reproduction
• Bacteria divide by binary
  fission. One bacterium can
  become ½ a million in about 6
  hours.

• No mitosis or meiosis because
  no nucleus

• Chromosome doubles and cells
  splits in half
• Writing scientific names:
Genus:
Arrangement (prefix):
   Strepto – chains or filaments
   Staphylo – clusters
   Diplo – pairs
Shapes
   Bacillus – rod
   Coccus – round / spherical /circular shape
   Sprillum – spiral shape

Example: Streptococcus thermophilus
    Famous Microbiologists
•Hooke – named the cell
•Leewenhoek – saw first
 organism
•Erlich – Magic Bullet Theory
•Fleming – discovered
 penicillin
•Gram – staining and
 classification
  Discovery of Penicillin: First Antibiotic




   From: Time, March 31, 2003


•Fleming happened to observe that Petri dishes with
 molds had killed bacteria in rings around the mold
•He postulated that the “mold juice” had killed the
 bacteria
•The mold was Penicillium notatum and the “juice” was
 named Penicillin
                   Normal Flora
• Skin
  – Staphylococcus
• Throat
  – Streptococcus
• Mouth
  – Lactobacillus
• Large intestines
  – E. coli



  Flora – population of microbes
  inhabiting the outside or inside
  surface of people or other animals.
Beneficial Bacteria
• Clean Environment - help clean up environmental disasters
  such as petroleum and chemical spills (oil spills)
• Mining companies
• Make minerals
• Sulfur conversion – technique can be used to harvest copper
  or uranium
• Nitrogen Cycle – bacteria covert the atmospheric nitrogen
  into a usable form, ammonia (nitrogen-fixing bacteria)
• Make antibiotics
• Chemicals – acetone or butanol
• Genetic Engineering – used to produce many products such
  as drugs for medicine and complex chemicals for research
   – Can be used as a vector
• Food Production
   – Pickles, sauerkraut, cheese, yougurt, sourdough bread,
     buttermilk, olives, vinegar, some kinds of sausages
BACTERIAL DISEASES
          Bacterial Infections
• Flesh Eating Disease
  – Quick progression
  – Staphylococcus
  – Destroys muscles
  – Strong toxins
    produced that
    dehydrates
  – Tissue death
  – Requires
  debridement
• Tetanus
  – Clostridium
  – Rust entry
  – Muscle spasms, fast
    heart rate, heavy
    sweating, low fever,
    lockjaw
  – Prevent with
    vaccine
• Syphilis
  – Treponema
  – Primary symptoms:
    chancre
  – Secondary: lesions, swollen
    lymph glands, rash on palms
    of hands and soles of feet,
    anorexia, alopecia
  – Tertiary: bone lesions, gastric
    pain, palate destruction,
    personality change
  – Treat in 1 or 2 stage
• Gonorrhea
  – Neisseria
  – Enters macrophages
  – Male symptoms:
    swollen urethra, thick
    brown discharge,
    redness, itchy, scaling
  – Female symptoms:
    usually asymptomatic
  – Causes blindness in
    babies – silver nitrate
  – Some species
    showing antibiotic
    resistance
• Lymes Disease
  – Borrelia, tick bite
  – Stage 1 – bulls eye
    rash, hives, neck
    stiffness,
  – Stage 2 – facial palsy,
    swollen heart,
    neurological
    abnormalities
  – Stage 3 – dementia,
    arthritis
  – Antibiotics must be
    able to cross the BBB
• Staph Infections
  – Staphylococcus
  – Redness, warm to
    touch, red streaks
    from infection site
  – Spreads quickly
• Anthrax
  – Bacillus
  – Direct contact with
    infected animals
  – 1-15 day incubation
  – Ulcers called eschars,
    headache, fever,
    nausea
  – Endospores viable for
    decades
  – UV inactivates spores
  – Cutaneous and
    respiratory
• Cholera
  – Vibrio
  – Food or water
    contamination from
    shellfish feces
  – Gulf coast of US
  – Bacteria attach to
    walls of small
    intestines causing
    hypersecretion of
    water
  – Cramps, vomiting, 3-4
    gallons of diarrhea a
    day

				
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posted:12/9/2012
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