bacteria: the good, the bad and the ugly anne todgham and annick gauthier university of british...
TRANSCRIPT
Bacteria: the good, the bad and the ugly
Anne Todgham and Annick Gauthier
University of British Columbia
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
Pictures of Bacteria
Anthrax
Anabena
Bacteria from Fish
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!
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
Why we should love Why we should love bacteriabacteria
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
Our bodies provide bacteria with:
We are a great home to live in!!We are a great home to live in!!
Why bacteria love us
Constant supply of nutrients Stable environment and constant temperature Protection Transportation
Interesting tidbits 1013 bacteria in/on human body, and only 1012
human cells 109 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.
More cool bacteria More cool bacteria numbersnumbers
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
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
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 37oC at UBC for 2 days Plates will be stored in fridge until October 23
when we will return to discuss results with you
Materials and MethodsObjectiveObjective: to culture bacteria from around the classroom and
your body
MaterialsMaterials: 1 LB agar plate, 4 cotton swabs, pencil and paper to take notes, marker
MethodMethod:
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
Pictorial of Procedure
Next class:
Growing Bacteria thumb mouth, nose or ear floor table phone keyboard light switch sink sink faucet toilet handle toilet
Culturing Bacteria
Identification of Bacteria
Grow bacteria on different media Different bacteria grow on
different types of plates Check for antibiotic
resistanceJessica’s expt
Use stains or antibodies Gram stain Antibodies “agglutinate”
Clump up bacteria DNA
amplify certain genes
How do we defend ourselves? Non-specific
Skin Hair Shedding cells Tears Macrophages Good bacteria!
Specific Antibodies B cells T cells
Picture of Gastrointestinal Tract
Bacteria of the mouthBacteria 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
Picture of Respiratory System
Life without bacteriaLife 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
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