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Bacteria: the good, the bad and the ugly Anne Todgham and Annick Gauthier University of British Columbia.

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Presentation on theme: "Bacteria: the good, the bad and the ugly Anne Todgham and Annick Gauthier University of British Columbia."— Presentation transcript:


2 Bacteria: the good, the bad and the ugly Anne Todgham and Annick Gauthier University of British Columbia

3 What are bacteria? Small organisms - several µm (1/1000 of a cm, can only see 1/100) They have all they need to live  DNA  Energy  Food  Can make proteins Good and bad bacteria!!!!!! Bacteria can be killed with antibiotics Viruses are different - need host to “live”  Can’t kill virus with antibiotics Rod-like Bacteria

4 Pictures of Bacteria Anthrax Anabena Bacteria from Fish

5 Where are bacteria? On our skin In our intestinal tract  Help us digest food In our mouth, throat In the soil In the ocean In the forest On plants Everywhere!

6 Good vs Bad Some bacteria cause disease  meningitis  pneumoniae  diarrhea Good bacteria too: for example E. coli  there are disease-causing strains  there are digestion-helping strains

7 Why we should love bacteria Live happily in the guts and lungs of animals  aid in digestion of food and vitamin production  stimulate the growth of some of our tissues Fight foreign disease causing bacteria and prevent them from infecting us Important in the cycling of nutrients in the environment ex. nitrogen and carbon Make up the bottom of most food webs  critical for the survival of most living organisms  thought to be the origin of multicellular organisms

8 Our bodies provide bacteria with: We are a great home to live in!! Why bacteria love us Constant supply of nutrients Stable environment and constant temperature Protection Transportation

9 Interesting tidbits 10 13 bacteria in/on human body, and only 10 12 human cells 10 9 bacteria per gram of feces (population of world) Only a very small number of “bad” bacteria We breathe in 3-4 bacteria per breath Number one infection: cavities 50% of worlds population dies of infectious diseases (20% in our society) Infectious diseases are the leading cause for taking time off of work More people died in the Civil War of infectious disease that by bullets.

10 More cool bacteria numbers Oldest fossil known is bacteria-like organisms that are 3.5 billion years old!! 100 000 bacteria in each cm2 of skin 1 billion bacteria in a teaspoon of soil 80 distinguishable species of bacteria living in the mouth alone Greater than 200 species of bacteria living on the entire body Can reproduce every 20 min

11 Uses for Bacteria Production of antibiotics like streptomycin and nocardicin Put the tang in yogurt and the sour in sour cream Vaccination (dead or weak bugs used to boost our immune system) Can be used to break down oil after an oil spill

12 Growing Bacteria All the bacteria that we will grow are normal bacteria that do not cause disease Bacteria grow in colonies on a substance called agar that contains sugars and salts We have poured these agar plates for you  CONDUCT EXPERIMENT Incubate plates at 37 o C at UBC for 2 days Plates will be stored in fridge until October 23 when we will return to discuss results with you

13 Materials and Methods Objective Objective: to culture bacteria from around the classroom and your body Materials Materials: 1 LB agar plate, 4 cotton swabs, pencil and paper to take notes, marker Method Method: 1. Using black marker, divide plate into 4 quadrants, label plate with your name and the date in small letters 2. Choose which 4 areas you will swab and record this in your science duotang 3. Label the plate with the areas you will swab  note label the bottom (i.e. agar containing part of the plate) 4. Remove one sterile swab from its packaging (do not touch it), swab area of choice by gently rubbing cotton swab on it, and then transferring this to the LB agar plate by gently rubbing the agar in the designated quadrant 5. Repeat step 4 for 3 other areas of choice 6. Clean up: put LB plate and marker into middle of your table, put all cotton swabs and wrappers into orange garbage bag

14 Pictorial of Procedure Next class:

15 Growing Bacteria thumb mouth, nose or ear floor table phone keyboard light switch sink sink faucet toilet handle toilet

16 Culturing Bacteria


18 Identification of Bacteria Grow bacteria on different media  Different bacteria grow on different types of plates  Check for antibiotic resistance  Jessica’s expt Use stains or antibodies  Gram stain  Antibodies “agglutinate”  Clump up bacteria DNA  amplify certain genes

19 How do we defend ourselves? Non-specific  Skin  Hair  Shedding cells  Tears  Macrophages  Good bacteria! Specific  Antibodies  B cells  T cells

20 Picture of Gastrointestinal Tract

21 Bacteria of the mouth Dental plaque, cavities and periodontal disease result from the actions initiated by our normal bacterial flora 60-70% of the volume of plaque is made of bacteria -- these bacteria release lactic acid that breaks down the enamel of the teeth and can cause cavities and further infection of your mouth

22 Picture of Respiratory System

23 Life without bacteria Normal bacterial flora are very important in protecting our bodies from pathogenic or disease-causing bacteria Administration of broad-spectrum antibiotics has a profound effect on our “good” bacteria and can result in “bad” antibiotic- resistant bacteria infecting our bodies Animals raised in an environment filled with bacteria are much healthier than those raised in a sterile environment Clean hypothesis  People need bacteria to live

24 How can we stay healthy? Good nutrition Low stress Age Cleanliness  but we need bacteria  antibacterial soaps Regular doctor and dental visits Vaccines up to date

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