Microbiology power point
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Ubiquityofmicrobespresentation.pptxUbiquity of Microbes
Ubiquity of Bacteria and Fungi
Bacteria and fungi have successfully adapted to a wide range of habitats
“Ubiquitous” in nature
You can find them in soil, water, plants, animals. You name it, bacteria/fungi probably live in it
Most are not capable of causing disease
They live their life, you live yours
Often play an important role in decomposing dead organisms
Circle of life
There are microbes living all around you!
For this experiment, you and your group will pick up microbes from an environment (cell phone, shoe) using a sterile cotton swab and transfer them to nutrient-rich plates
We’ll let the microbes grow to enormous numbers at room temperature for one week
Millions of cells grow within each colony!
Here's a helpful video on swabbing technique:
Environments to test (ideas)
Kiss/tongue the plate (Do this first!)
Lightly press fingers on agar
Cough into a plate
Swab a phone (but not the touchscreen), keyboard, or mouse
Touchscreens have an electrical charge that kills microbes
Swab nostrils, armpits, or scalp skin
Swab your earbuds
Swab under fingernails
Swab bottom of your shoe
Swab bottom of your bookbag
Swab garden soil
Swab bathroom toilet seat (men and women’s)
Swab an elevator button or door handle
Lab instructions
Day 1:
Each group needs 2 nutrient-rich plates, 4 sterile cotton swabs, a sharpie/wax pencil for labelling, and a sterile water tube
With the swabs, you’ll pick up microbes living in four different environments and transfer them to your two plates
Only write on the base of the plate. Divide each plate in half with your wax pencil. Label one half with the first environment you choose, label the second with the other site
Also, put a name/symbol on the plate so you know it’s from your group
Go to the chosen environment, dunk the swab in the sterile saline solution, then rub the area with your wet swab
Why do you think the swabs are dunked in the saline?
Rub the swab over the entirety of one half of a plate
Be careful not to press too hard on the agar or you might tear it
Repeat for the second, third, and fourth environments
Bring your environmental plates to the metal pan, and place them lid-side down
Then we’ll let the microbes grow at room temperature for a week
Be sure to throw out the used swabs in the biohazard bin after using them
PART TWO. What grew on the plates?
Either bacteria or fungi grew on the plates
If the growth looks fuzzy, it’s likely a mold fungus among us
Most, non-fuzzy growth on your plates are bacteria
Environmental fungus you may find
Rhodotorula is a type of single-celled yeast (fungus) that is commonly found in soil and water environments
Distinguishable by its orange-red color
Environmental fungus you may find
Zygomycetes produce black reproductive spores that gets released to seed new environments
The black spores gives Rhizopus stolonifer, commonly known as the black bread mold, its color
Environmental fungus you may find
Penicillium is a very common environmental fungi. Are commonly blue-green or white in color
Non-pathogenic to humans
Mainly act as decomposers but some species make useful products like antibiotics (penicillin) and cheeses (blue cheese)
Environmental bacteria you may find
Streptomyces is a bacteria that is abundant in the soil. The bacteria grows as wrinkled colonies on the plate
Some species produce antibiotics that we use to treat disease
Many rod-shaped Bacillus bacteria live on plants and in the soil. Bacillus typically form large, white colonies
Some species produce antibiotics that we use to treat disease
Growth that has a spiral, webbed pattern is Bacillus mycoides, another soil bacteria
Environmental bacteria you may find
Escherichia coli are rod-shaped bacteria commonly found in the gastrointestinal tracts of mammals
Most E. coli harmlessly live in our guts, but some types (E. coli O157:H7) can cause food poisoning
It easily spreads to humans via the fecal-oral route
E. coli grow as moderately-sized, greyish colonies
Environmental bacteria you may find
Bright yellow, shiny colonies are likely Micrococcus luteus, a harmless bacteria that lives on our skin and in our mouth
The small, shiny, creamy-white (or light orange/yellow) colonies are likely Staphylococcus
This spherical bacteria lives on your skin and is commonly found on body environments and the things we commonly touch
Environmental bacteria you may find
Streptococcus are round-shaped bacteria commonly found in the mouth and throat
Some are disease-causing, like Streptococcus pyogenes (Strep throat)
Streptococcus grow as very tiny, clearish colonies
Environmental bacteria you may find
Streptococcus colonies (tiny dots)
Staphylococcus aureus (creamy-white colonies)
Lab assignment instructions (10 points)
You and your group will attempt to identify the environmental microbes present on 8 different growth plates
You’ll take a picture of the growth on each of the 8 plates and include the pictures in your assignment submission
As long as there isn’t moldy growth on the plate, its fine to remove the lid to take a better photo of the environments we tested. But be careful!
For each plate, note the environments and identify 2-3 species of microbe (bacteria or fungi). Mention the growth characteristics that led you to identification (color, shape, size, environment, etc.)
Use this lab PowerPoint to help identify the microbes based on their colony appearance and environment tested
Be sure to use arrows to point out the organisms that you have identified!
You’ll submit this assignment individually. Use Microsoft PowerPoint or Word to compile your assignment and to answer the questions below
In the “Content” menu on Brightspace, you will find a menu named “Ubiquity of microbes group lab information”. There you will find examples of previous student submissions
Be sure to put your name and class section before submitting!
Email your file to me before midnight on the date listed in the syllabus course calendar
Questions to answer with your submission
You identified bacteria by the presence of colonies. How many bacterial cells reside in a colony?
Which environment/s had the most microbial growth? Why do you think that is?
Which environment/s had the least microbial growth? Why do you think that is?
Did any of the results surprise you? Explain.
You can get a free copy of Microsoft Office, including PowerPoint and Word: http://www.ccc.edu/services/pages/get-a-copy-of-microsoft-office-for-students.aspx
